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Sample records for pancreatic beta-cell homeostasis

  1. Redox Homeostasis in Pancreatic beta Cells

    Czech Academy of Sciences Publication Activity Database

    Ježek, Petr; Dlasková, Andrea; Plecitá-Hlavatá, Lydie

    2012-01-01

    Roč. 2012, č. 2012 (2012), s. 932838 ISSN 1942-0900 R&D Projects: GA ČR(CZ) GAP302/10/0346; GA ČR(CZ) GPP304/10/P204 Institutional support: RVO:67985823 Keywords : beta cells * reactive oxygen species homeostasis * mitochondria Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 3.393, year: 2012

  2. Planar Cell Polarity Controls Pancreatic Beta Cell Differentiation and Glucose Homeostasis

    Directory of Open Access Journals (Sweden)

    Cedric Cortijo

    2012-12-01

    Full Text Available Planar cell polarity (PCP refers to the collective orientation of cells within the epithelial plane. We show that progenitor cells forming the ducts of the embryonic pancreas express PCP proteins and exhibit an active PCP pathway. Planar polarity proteins are acquired at embryonic day 11.5 synchronously to apicobasal polarization of pancreas progenitors. Loss of function of the two PCP core components Celsr2 and Celsr3 shows that they control the differentiation of endocrine cells from polarized progenitors, with a prevalent effect on insulin-producing beta cells. This results in a decreased glucose clearance. Loss of Celsr2 and 3 leads to a reduction of Jun phosphorylation in progenitors, which, in turn, reduces beta cell differentiation from endocrine progenitors. These results highlight the importance of the PCP pathway in cell differentiation in vertebrates. In addition, they reveal that tridimensional organization and collective communication of cells are needed in the pancreatic epithelium in order to generate appropriate numbers of endocrine cells.

  3. Measuring phospholipase D activity in insulin-secreting pancreatic beta-cells and insulin-responsive muscle cells and adipocytes.

    Science.gov (United States)

    Cazzolli, Rosanna; Huang, Ping; Teng, Shuzhi; Hughes, William E

    2009-01-01

    Phospholipase D (PLD) is an enzyme producing phosphatidic acid and choline through hydrolysis of phosphatidylcholine. The enzyme has been identified as a member of a variety of signal transduction cascades and as a key regulator of numerous intracellular vesicle trafficking processes. A role for PLD in regulating glucose homeostasis is emerging as the enzyme has recently been identified in events regulating exocytosis of insulin from pancreatic beta-cells and also in insulin-stimulated glucose uptake through controlling GLUT4 vesicle exocytosis in muscle and adipose tissue. We present methodologies for assessing cellular PLD activity in secretagogue-stimulated insulin-secreting pancreatic beta-cells and also insulin-stimulated adipocyte and muscle cells, two of the principal insulin-responsive cell types controlling blood glucose levels.

  4. Ins1 Cre knock-in mice for beta cell-specific gene recombination

    OpenAIRE

    Thorens Bernard; Tarussio David; Maestro Miguel Angel; Maestro Miguel Angel; Rovira Meritxell; Rovira Meritxell; Heikkilä Eija; Ferrer Jorge; Ferrer Jorge; Ferrer Jorge

    2013-01-01

    Aims/hypothesis Pancreatic beta cells play a central role in the control of glucose homeostasis by secreting insulin to stimulate glucose uptake by peripheral tissues. Understanding the molecular mechanisms that control beta cell function and plasticity has critical implications for the pathophysiology and therapy of major forms of diabetes. Selective gene inactivation in pancreatic beta cells, using the Cre-lox system, is a powerful approach to assess the role of particular genes in beta cel...

  5. The expression of dominant negative TCF7L2 in pancreatic beta cells during the embryonic stage causes impaired glucose homeostasis

    Directory of Open Access Journals (Sweden)

    Weijuan Shao

    2015-04-01

    Conclusions: Our observations support a cell autonomous role for TCF7L2 in pancreatic β-cells suggested by most, though not all, investigations. βTCFDN is a novel model for further exploring the role of TCF7L2 in β-cell genesis and metabolic homeostasis.

  6. Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death.

    Science.gov (United States)

    Clark, Amy L; Kanekura, Kohsuke; Lavagnino, Zeno; Spears, Larry D; Abreu, Damien; Mahadevan, Jana; Yagi, Takuya; Semenkovich, Clay F; Piston, David W; Urano, Fumihiko

    2017-07-17

    Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca 2+ -ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.

  7. Lysosome associated membrane proteins maintain pancreatic acinar cell homeostasis: LAMP-2 deficient mice develop pancreatitis.

    Science.gov (United States)

    Mareninova, Olga A; Sendler, Matthias; Malla, Sudarshan Ravi; Yakubov, Iskandar; French, Samuel W; Tokhtaeva, Elmira; Vagin, Olga; Oorschot, Viola; Lüllmann-Rauch, Renate; Blanz, Judith; Dawson, David; Klumperman, Judith; Lerch, Markus M; Mayerle, Julia; Gukovsky, Ilya; Gukovskaya, Anna S

    2015-11-01

    The pathogenic mechanism of pancreatitis is poorly understood. Recent evidence implicates defective autophagy in pancreatitis responses; however, the pathways mediating impaired autophagy in pancreas remain largely unknown. Here, we investigate the role of lysosome associated membrane proteins (LAMPs) in pancreatitis. We analyzed changes in LAMPs in experimental models and human pancreatitis, and the underlying mechanisms: LAMP de-glycosylation and degradation. LAMP cleavage by cathepsin B (CatB) was analyzed by mass spectrometry. We used mice deficient in LAMP-2 to assess its role in pancreatitis. Pancreatic levels of LAMP-1 and LAMP-2 greatly decrease across various pancreatitis models and in human disease. Pancreatitis does not trigger LAMPs' bulk de-glycosylation, but induces their degradation via CatB-mediated cleavage of LAMP molecule close to the boundary between luminal and transmembrane domains. LAMP-2 null mice spontaneously develop pancreatitis that begins with acinar cell vacuolization due to impaired autophagic flux, and progresses to severe pancreas damage characterized by trypsinogen activation, macrophage-driven inflammation, and acinar cell death. LAMP-2 deficiency causes a decrease in pancreatic digestive enzymes content, stimulates the basal and inhibits CCK-induced amylase secretion by acinar cells. The effects of LAMP-2 knockout and acute cerulein pancreatitis overlap, which corroborates the pathogenic role of LAMP decrease in experimental pancreatitis models. The results indicate a critical role for LAMPs, particularly LAMP-2, in maintaining pancreatic acinar cell homeostasis, and provide evidence that defective lysosomal function, resulting in impaired autophagy, leads to pancreatitis. Mice with LAMP-2 deficiency present a novel genetic model of human pancreatitis caused by lysosomal/autophagic dysfunction.

  8. Proton microprobe analysis of pancreatic. beta. cells

    Energy Technology Data Exchange (ETDEWEB)

    Lindh, U [Uppsala Univ. (Sweden). Gustaf Werner Inst.; Juntti-Berggren, L; Berggren, P O; Hellman, B [Uppsala Univ. (Sweden)

    1985-01-01

    Freeze-dried pancreas sections from obese hyperglycemic mice were subjected to proton bombardment and the elemental contents in the ..beta.. cells and the exocrine part were obtained from the characteristic X-rays emitted. Quantitative data were provided for 18 different elements. The mole ratio between K and Na exceeded 10, implying that neither the sample preparation nor the irradiation had induced significant diffuse changes. With the demonstration of this high K/Na ratio it seems likely that also the ..beta.. cells are equipped with an efficient Na/sup +//K/sup +/ pump. The ..beta.. cells contained about 70 mmoles Cl per litre cell water. Observed amounts of Ca and Mg were equivalent to those previously recorded by electrothermal atomic absorption spectroscopy. The significant role of Zn for the storage of insulin was emphasized by the demonstration of 3 times as much of this element in the ..beta.. cells as compared with the exocrine pancreas. In addition, the sensitivity of the proton microprobe enabled measurements of various trace elements such as Rb, Cr, Cu, Al and Pb not previously demonstrated in the pancreatic ..beta.. cells.

  9. Planar Cell Polarity Controls Pancreatic Beta Cell Differentiation and Glucose Homeostasis

    DEFF Research Database (Denmark)

    Cortijo, Cedric; Gouzi, Mathieu; Tissir, Fadel

    2012-01-01

    glucose clearance. Loss of Celsr2 and 3 leads to a reduction of Jun phosphorylation in progenitors, which, in turn, reduces beta cell differentiation from endocrine progenitors. These results highlight the importance of the PCP pathway in cell differentiation in vertebrates. In addition, they reveal.......5 synchronously to apicobasal polarization of pancreas progenitors. Loss of function of the two PCP core components Celsr2 and Celsr3 shows that they control the differentiation of endocrine cells from polarized progenitors, with a prevalent effect on insulin-producing beta cells. This results in a decreased...

  10. ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function

    International Nuclear Information System (INIS)

    Pi Jingbo; Zhang Qiang; Fu Jingqi; Woods, Courtney G.; Hou Yongyong; Corkey, Barbara E.; Collins, Sheila; Andersen, Melvin E.

    2010-01-01

    This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H 2 O 2 , act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function.

  11. Hypothyroidism in utero stimulates pancreatic beta cell proliferation and hyperinsulinaemia in the ovine fetus during late gestation.

    Science.gov (United States)

    Harris, Shelley E; De Blasio, Miles J; Davis, Melissa A; Kelly, Amy C; Davenport, Hailey M; Wooding, F B Peter; Blache, Dominique; Meredith, David; Anderson, Miranda; Fowden, Abigail L; Limesand, Sean W; Forhead, Alison J

    2017-06-01

    Thyroid hormones are important regulators of growth and maturation before birth, although the extent to which their actions are mediated by insulin and the development of pancreatic beta cell mass is unknown. Hypothyroidism in fetal sheep induced by removal of the thyroid gland caused asymmetric organ growth, increased pancreatic beta cell mass and proliferation, and was associated with increased circulating concentrations of insulin and leptin. In isolated fetal sheep islets studied in vitro, thyroid hormones inhibited beta cell proliferation in a dose-dependent manner, while high concentrations of insulin and leptin stimulated proliferation. The developing pancreatic beta cell is therefore sensitive to thyroid hormone, insulin and leptin before birth, with possible consequences for pancreatic function in fetal and later life. The findings of this study highlight the importance of thyroid hormones during pregnancy for normal development of the fetal pancreas. Development of pancreatic beta cell mass before birth is essential for normal growth of the fetus and for long-term control of carbohydrate metabolism in postnatal life. Thyroid hormones are also important regulators of fetal growth, and the present study tested the hypotheses that thyroid hormones promote beta cell proliferation in the fetal ovine pancreatic islets, and that growth retardation in hypothyroid fetal sheep is associated with reductions in pancreatic beta cell mass and circulating insulin concentration in utero. Organ growth and pancreatic islet cell proliferation and mass were examined in sheep fetuses following removal of the thyroid gland in utero. The effects of triiodothyronine (T 3 ), insulin and leptin on beta cell proliferation rates were determined in isolated fetal ovine pancreatic islets in vitro. Hypothyroidism in the sheep fetus resulted in an asymmetric pattern of organ growth, pancreatic beta cell hyperplasia, and elevated plasma insulin and leptin concentrations. In pancreatic

  12. Biotin uptake by mouse and human pancreatic beta cells/islets: a regulated, lipopolysaccharide-sensitive carrier-mediated process

    Science.gov (United States)

    Ghosal, Abhisek; Sekar, Thillai V.

    2014-01-01

    Biotin is essential for the normal function of pancreatic beta cells. These cells obtain biotin from their surroundings via transport across their cell membrane. Little is known about the uptake mechanism involved, how it is regulated, and how it is affected by internal and external factors. We addressed these issues using the mouse-derived pancreatic beta-TC-6 cells and freshly isolated mouse and human primary pancreatic beta cells as models. The results showed biotin uptake by pancreatic beta-TC-6 cells occurs via a Na+-dependent, carrier-mediated process, that is sensitive to desthiobiotin, as well as to pantothenic acid and lipoate; the process is also saturable as a function of concentration (apparent Km = 22.24 ± 5.5 μM). These cells express the sodium-dependent multivitamin transporter (SMVT), whose knockdown (with doxycycline-inducible shRNA) led to a sever inhibition in biotin uptake. Similarly, uptake of biotin by mouse and human primary pancreatic islets is Na+-dependent and carrier-mediated, and both cell types express SMVT. Biotin uptake by pancreatic beta-TC-6 cells is also adaptively regulated (via transcriptional mechanism) by extracellular substrate level. Chronic treatment of pancreatic beta-TC-6 cells with bacterial lipopolysaccharides (LPS) leads to inhibition in biotin uptake. This inhibition is mediated via a Toll-Like receptor 4-mediated process and involves a decrease in membrane expression of SMVT. These findings show, for the first time, that pancreatic beta cells/islets take up biotin via a specific and regulated carrier-mediated process, and that the process is sensitive to the effect of LPS. PMID:24904078

  13. SIRT1 inhibits proliferation of pancreatic cancer cells expressing pancreatic adenocarcinoma up-regulated factor (PAUF), a novel oncogene, by suppression of {beta}-catenin

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Il-Rae [WCU, Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Koh, Sang Seok [Immunotherapy Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-333 (Korea, Republic of); Department of Functional Genomics, University of Science and Technology, Daejeon 305-333 (Korea, Republic of); Malilas, Waraporn; Srisuttee, Ratakorn; Moon, Jeong [WCU, Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Choi, Young-Whan [Department of Horticultural Bioscience, Pusan National University, Miryang 627-706 (Korea, Republic of); Horio, Yoshiyuki [Department of Pharmacology, Sapporo Medical University, Sapporo 060-8556 (Japan); Oh, Sangtaek [Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seoul 136-702 (Korea, Republic of); Chung, Young-Hwa, E-mail: younghc@pusan.ac.kr [WCU, Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2012-06-29

    Highlights: Black-Right-Pointing-Pointer SIRT1 inhibits protein levels of {beta}-catenin and its transcriptional activity. Black-Right-Pointing-Pointer Nuclear localization of SIRT1 is not required for the decrease of {beta}-catenin expression. Black-Right-Pointing-Pointer SIRT1-mediated degradation of {beta}-catenin is not required for GSK-3{beta} and Siah-1 but for proteosome. Black-Right-Pointing-Pointer SIRT1 activation inhibits proliferation of pancreatic cancer cells expressing PAUF. -- Abstract: Because we found in a recent study that pancreatic adenocarcinoma up-regulated factor (PAUF), a novel oncogene, induces a rapid proliferation of pancreatic cells by up-regulation of {beta}-catenin, we postulated that {beta}-catenin might be a target molecule for pancreatic cancer treatment. We thus speculated whether SIRT1, known to target {beta}-catenin in a colon cancer model, suppresses {beta}-catenin in those pancreatic cancer cells that express PAUF (Panc-PAUF). We further evaluated whether such suppression would lead to inhibition of the proliferation of these cells. The ectopic expression of either SIRT1 or resveratrol (an activator of SIRT1) suppressed levels of {beta}-catenin protein and its transcriptional activity in Panc-PAUF cells. Conversely, suppression of SIRT1 expression by siRNA enhanced {beta}-catenin expression and transcriptional activity. SIRT1 mutant analysis showed that nuclear localization of SIRT1 is not required for reduction of {beta}-catenin. Treatment with MG132, a proteasomal inhibitor, restored {beta}-catenin protein levels, suggesting that SIRT1-mediated degradation of {beta}-catenin requires proteasomal activity. It was reported that inhibition of GSK-3{beta} or Siah-1 stabilizes {beta}-catenin in colon cancer cells, but suppression of GSK-3{beta} or Siah-1 using siRNA in the presence of resveratrol instead diminished {beta}-catenin protein levels in Panc-PAUF cells. This suggests that GSK-3{beta} and Siah-1 are not involved in SIRT1

  14. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic {beta} cells

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Mirshahi, Faridoddin [Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Grider, John R. [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Murthy, Karnam S., E-mail: skarnam@vcu.edu [Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA (United States); Sanyal, Arun J., E-mail: asanyal@mcvh-vcu.edu [Division of Gastroenterology, Hepatology and Nutrition, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA (United States)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer G protein coupled receptor TGR5 is expressed in mouse and human islets. Black-Right-Pointing-Pointer TGR5 is coupled to activation of Gs and Ca{sup 2+} release via cAMP/Epac/PLC-{epsilon} pathway. Black-Right-Pointing-Pointer Activation of TGR5 by bile salts and selective ligands causes insulin secretion. Black-Right-Pointing-Pointer TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic {beta} cells. In the present study, we have identified the expression of TGR5 in pancreatic {beta} cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated G{alpha}{sub s} and caused an increase in intracellular cAMP and Ca{sup 2+}. OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective G{alpha}{sub s} inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G{sub s}/cAMP/Ca{sup 2+} pathway. 8-pCPT-2 Prime -O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic {beta} cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  15. Regulation of pancreatic beta-cell mass and proliferation by SOCS-3

    DEFF Research Database (Denmark)

    Lindberg, K; Rønn, S G; Tornehave, D

    2005-01-01

    Growth hormone and prolactin are important growth factors for pancreatic beta-cells. The effects exerted by these hormones on proliferation and on insulin synthesis and secretion in beta-cells are largely mediated through the Janus kinase (JAK)/signal transducer and activator of transcription (ST...

  16. Influence and timing of arrival of murine neural crest on pancreatic beta cell development and maturation.

    Science.gov (United States)

    Plank, Jennifer L; Mundell, Nathan A; Frist, Audrey Y; LeGrone, Alison W; Kim, Thomas; Musser, Melissa A; Walter, Teagan J; Labosky, Patricia A

    2011-01-15

    Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of insulin-expressing cells and insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic insulin granules and the presence of abnormal granules in insulin-expressing cells from mutant embryos. Together, these data demonstrate that

  17. Re-exposure to beta cell autoantigens in pancreatic allograft recipients with preexisting beta cell autoantibodies.

    Science.gov (United States)

    Mujtaba, Muhammad Ahmad; Fridell, Jonathan; Book, Benita; Faiz, Sara; Sharfuddin, Asif; Wiebke, Eric; Rigby, Mark; Taber, Tim

    2015-11-01

    Re-exposure to beta cell autoantigens and its relevance in the presence of donor-specific antibodies (DSA) in pancreatic allograft recipients is not well known. Thirty-three patients requiring a pancreas transplant were enrolled in an IRB approved study. They underwent prospective monitoring for DSA and beta cell autoantibody (BCAA) levels to GAD65, insulinoma-associated antigen 2 (IA-2), insulin (micro-IAA [mIAA]), and islet-specific zinc transporter isoform-8 (ZnT8). Twenty-five (75.7%) had pre-transplant BCAA. Twenty had a single antibody (mIAA n = 15, GAD65 n = 5); five had two or more BCAA (GAD65 + mIAA n = 2, GAD65 + mIAA+IA-2 n = 2, GA65 + mIAA+IA-2 + ZnT8 = 1). No changes in GAD65 (p > 0.29), IA-2 (>0.16), and ZnT8 (p > 0.07) were observed between pre-transplant and post-transplant at 6 or 12 months. A decrease in mIAA from pre- to post-6 months (p BCAA was observed at one yr. Seven (21.0%) developed de novo DSA. The incidence of DSA was 24% in patients with BCAA vs. 25% in patients without BCAA (p = 0.69). Pancreatic allograft function of patients with vs. without BCAA, and with and without BCAA + DSA was comparable until last follow-up (three yr). Re-exposure to beta cell autoantigens by pancreas transplant may not lead to increased levels or development of new BCAA or pancreatic allograft dysfunction. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. The Fas pathway is involved in pancreatic beta cell secretory function

    DEFF Research Database (Denmark)

    Schumann, Desiree M; Maedler, Kathrin; Franklin, Isobel

    2007-01-01

    Pancreatic beta cell mass and function increase in conditions of enhanced insulin demand such as obesity. Failure to adapt leads to diabetes. The molecular mechanisms controlling this adaptive process are unclear. Fas is a death receptor involved in beta cell apoptosis or proliferation, depending...... on the activity of the caspase-8 inhibitor FLIP. Here we show that the Fas pathway also regulates beta cell secretory function. We observed impaired glucose tolerance in Fas-deficient mice due to a delayed and decreased insulin secretory pattern. Expression of PDX-1, a beta cell-specific transcription factor...... regulating insulin gene expression and mitochondrial metabolism, was decreased in Fas-deficient beta cells. As a consequence, insulin and ATP production were severely reduced and only partly compensated for by increased beta cell mass. Up-regulation of FLIP enhanced NF-kappaB activity via NF...

  19. The potential role of SOCS-3 in the interleukin-1beta-induced desensitization of insulin signaling in pancreatic beta-cells

    DEFF Research Database (Denmark)

    Emanuelli, Brice; Glondu, Murielle; Filloux, Chantal

    2004-01-01

    insulin signaling is required for the optimal beta-cell function, we assessed the effect of IL-1beta on the insulin pathway in a rat pancreatic beta-cell line. We show that IL-1beta decreases insulin-induced tyrosine phosphorylation of the insulin receptor (IR) and insulin receptor substrate (IRS...

  20. Pancreatic Beta-Cell Purification by Altering FAD and NAD(PH Metabolism

    Directory of Open Access Journals (Sweden)

    P. de Vos

    2008-07-01

    Full Text Available Isolation of primary beta cells from other cells within in the pancreatic islets is of importance for many fields of islet research. However, up to now, no satisfactory method has been developed that gained high numbers of viable beta cells, without considerable alpha-cell contamination. In this study, we investigated whether rat beta cells can be isolated from nonbeta endocrine cells by manipulating the flavin adenine dinucleotide (FAD and nicotinamide-adenine dinucleotide phosphate (NAD(PH autofluorescence. Beta cells were isolated from dispersed islets by flow cytometry, based on their high FAD and NAD(PH fluorescence. To improve beta cell yield and purity, the cellular FAD and NAD(PH contents were altered by preincubation in culture media containing varying amounts of D-glucose and amino acids. Manipulation of the cellular FAD and NAD(PH fluorescence improves beta cell yield and purity after sorting. This method is also a fast and reliable method to measure beta cell functional viability. A conceivable application is assessing beta cell viability before transplantation.

  1. Growth hormone is a growth factor for the differentiated pancreatic beta-cell

    DEFF Research Database (Denmark)

    Linde, S; Welinder, B S; Billestrup, N

    1989-01-01

    The regulation of the growth of the pancreatic beta-cell is poorly understood. There are previous indications of a role of GH in the growth and insulin production of the pancreatic islets. In the present study we present evidence for a direct long-term effect of GH on proliferation and insulin...

  2. Reduced Expression of the Liver/Beta-Cell Glucose Transporter Isoform in Glucose-Insensitive Pancreatic Beta Cells of Diabetic Rats

    Science.gov (United States)

    Thorens, Bernard; Weir, Gordon C.; Leahy, John L.; Lodish, Harvey F.; Bonner-Weir, Susan

    1990-09-01

    Rats injected with a single dose of streptozocin at 2 days of age develop non-insulin-dependent diabetes 6 weeks later. The pancreatic beta islet cells of these diabetic rats display a loss of glucose-induced insulin secretion while maintaining sensitivity to other secretagogues such as arginine. We analyzed the level of expression of the liver/beta-cell glucose transporter isoform in diabetic islets by immunofluorescence staining of pancreas sections and by Western blotting of islet lysates. Islets from diabetic animals have a reduced expression of this beta-cell-specific glucose transporter isoform and the extent of reduction is correlated with the severity of hyperglycemia. In contrast, expression of this transporter isoform in liver is minimally modified by the diabetes. Thus a decreased expression of the liver/beta-cell glucose transporter isoform in beta cells is associated with the impaired glucose sensing characteristic of diabetic islets; our data suggest that this glucose transporter may be part of the beta-cell glucose sensor.

  3. Glucose-induced lipogenesis in pancreatic beta-cells is dependent on SREBP-1

    DEFF Research Database (Denmark)

    Sandberg, Maria B; Fridriksson, Jakob; Madsen, Lise

    2005-01-01

    High concentrations of glucose induce de novo fatty acid synthesis in pancreatic beta-cells and chronic exposure of elevated glucose and fatty acids synergize to induce accumulation of triglycerides, a phenomenon termed glucolipotoxicity. Here we investigate the role of sterol-regulatory element......, de novo fatty acid synthesis and lipid accumulation are induced primarily through sterol-regulatory elements (SREs) and not E-Boxes. Adenoviral expression of a dominant negative SREBP compromises glucose induction of some lipogenic genes and significantly reduces glucose-induction of de novo fatty...... acid synthesis. Thus, we demonstrate for the first time that SREBP activity is necessary for full glucose induction of de novo fatty acid synthesis in pancreatic beta-cells....

  4. Effect on pancreatic beta cells and nerve cells by low let x-ray

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kwang Hun [Dept. of Nuclear Medicine, Kyungbuk National University Hospital, Daegu (Korea, Republic of); Kim, Kgu Hwan [Dept. of Radiological Technology, Daegu health College, Daegu (Korea, Republic of)

    2014-03-15

    Cultured pancreatic beta cells and nerve cells, it is given normal condition of 10% FBS (fetal bovine serum), 11.1 mM glucose and hyperglycemia condition of 1% FBS, 30 mM glucose. For low LET X-ray irradiated with 0.5 Gy/hr dose-rate(total dose: 0.5 to 5 Gy). Survival rates were measured by MTT assay. When non irradiated, differentiated in the pancreatic beta cells experiment is hyperglycemia conditions survival rate compared to normal conditions survival rate seemed a small reduction. However increasing the total dose of X-ray, the survival rate of normal conditions decreased slightly compared to the survival rate of hyperglycemia conditions, the synergistic effect was drastically reduced. When non irradiated, undifferentiated in the nerve cells experiment is hyperglycemia conditions survival rate compared to normal conditions survival rate seemed a large reduction. As the cumulative dose of X-ray normal conditions and hyperglycemia were all relatively rapid cell death. But the rate of decreased survivals by almost parallel to the reduction proceed and it didn't show synergistic effect.

  5. Pancreatic beta-cell overexpression of the glucagon receptor gene results in enhanced beta-cell function and mass

    DEFF Research Database (Denmark)

    Gelling, Richard W; Vuguin, Patricia M; Du, Xiu Quan

    2009-01-01

    in vivo, we generated mice overexpressing the Gcgr specifically on pancreatic beta-cells (RIP-Gcgr). In vivo and in vitro insulin secretion in response to glucagon and glucose was increased 1.7- to 3.9-fold in RIP-Gcgr mice compared with controls. Consistent with the observed increase in insulin release...

  6. Lysosome-Associated Membrane Proteins (LAMP Maintain Pancreatic Acinar Cell Homeostasis: LAMP-2–Deficient Mice Develop PancreatitisSummary

    Directory of Open Access Journals (Sweden)

    Olga A. Mareninova

    2015-11-01

    Full Text Available Background & Aims: The pathogenic mechanism of pancreatitis is poorly understood. Recent evidence implicates defective autophagy in pancreatitis responses; however, the pathways mediating impaired autophagy in pancreas remain largely unknown. Here, we investigate the role of lysosome associated membrane proteins (LAMPs in pancreatitis. Methods: We analyzed changes in LAMPs in experimental models and human pancreatitis, and the underlying mechanisms: LAMP deglycosylation and degradation. LAMP cleavage by cathepsin B (CatB was analyzed by mass spectrometry. We used mice deficient in LAMP-2 to assess its role in pancreatitis. Results: Pancreatic levels of LAMP-1 and LAMP-2 greatly decrease across various pancreatitis models and in human disease. Pancreatitis does not trigger the LAMPs’ bulk deglycosylation but induces their degradation via CatB-mediated cleavage of the LAMP molecule close to the boundary between luminal and transmembrane domains. LAMP-2 null mice spontaneously develop pancreatitis that begins with acinar cell vacuolization due to impaired autophagic flux, and progresses to severe pancreas damage characterized by trypsinogen activation, macrophage-driven inflammation, and acinar cell death. LAMP-2 deficiency causes a decrease in pancreatic digestive enzymes content, and stimulates the basal and inhibits cholecystokinin-induced amylase secretion by acinar cells. The effects of LAMP-2 knockout and acute cerulein pancreatitis overlap, which corroborates the pathogenic role of LAMP decrease in experimental pancreatitis models. Conclusions: The results indicate a critical role for LAMPs, particularly LAMP-2, in maintaining pancreatic acinar cell homeostasis and provide evidence that defective lysosomal function, resulting in impaired autophagy, leads to pancreatitis. Mice with LAMP-2 deficiency present a novel genetic model of human pancreatitis caused by lysosomal/autophagic dysfunction. Keywords: Amylase Secretion, Autophagy

  7. Trans fatty acids increase nitric oxide levels and pancreatic beta-cell necrosis in rats

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    Kusmiyati Tjahjono DK

    2013-04-01

    Full Text Available Background The prevalence of diabetes in Indonesia is increasing due to various factors, including life style changes such as trans fatty acid (TFA intake. High TFA intake is known to be related to blood lipid profile changes resulting in cardiovascular disorders. This study was to identify the effect of TFA on nitric oxide (NO production and on necrosis of pancreatic beta cells. Methods A study of randomized pre-test post–test design with control group. Thirty Sprague Dawley rats were divided into 3 groups, i.e. group K (control, group P1 receiving a diet with 5% TFA, and P2 receiving 10% TFA. The intervention was performed for 8 weeks. NO level and pancreatic beta-cell necrosis were analyzed using Pearson’s chi square test. Results After 4 weeks of treatment there was no change in NO levels in group K, but increased NO in P2 (2.6-3.8 ìM. At 8 weeks after treatment, NO levels in groups P1 and P2 increased to 2.6-3.4 ìM and 4.2-14.3 ìM, respectively, while in group K only 2 rats had increased NO levels of 2.8-2.9 ìM. With Pearson’s chi-square test, there was a signifant difference in the proportions of necrotic pancreatic beta cells after 4 weeks and 8 weeks (p=0.000. No necrosis of beta cells was found in group K, mild necrosis in group P1 (1-25% and moderate necrosis in group P2 (26-50%. Conclusion TFA consumption significantly increases NO levels in Sprague Dawley rats and also results in moderate grades of necrosis of pancreatic beta cells.

  8. Trans fatty acids increase nitric oxide levels and pancreatic beta-cell necrosis in rats

    Directory of Open Access Journals (Sweden)

    Kusmiyati Tjahjono DK

    2015-12-01

    Full Text Available BACKGROUND The prevalence of diabetes in Indonesia is increasing due to various factors, including life style changes such as trans fatty acid (TFA intake. High TFA intake is known to be related to blood lipid profile changes resulting in cardiovascular disorders. This study was to identify the effect of TFA on nitric oxide (NO production and on necrosis of pancreatic beta cells. METHODS A study of randomized pre-test post–test design with control group. Thirty Sprague Dawley rats were divided into 3 groups, i.e. group K (control, group P1 receiving a diet with 5% TFA, and P2 receiving 10% TFA. The intervention was performed for 8 weeks. NO level and pancreatic beta-cell necrosis were analyzed using Pearson’s chi square test. RESULTS After 4 weeks of treatment there was no change in NO levels in group K, but increased NO in P2 (2.6-3.8 ìM. At 8 weeks after treatment, NO levels in groups P1 and P2 increased to 2.6-3.4 ìM and 4.2-14.3 ìM, respectively, while in group K only 2 rats had increased NO levels of 2.8-2.9 ìM. With Pearson’s chi-square test, there was a signifant difference in the proportions of necrotic pancreatic beta cells after 4 weeks and 8 weeks (p= 0.000. No necrosis of beta cells was found in group K, mild necrosis in group P1 (1-25% and moderate necrosis in group P2 (26-50%. CONCLUSION TFA consumption significantly increases NO levels in Sprague Dawley rats and also results in moderate grades of necrosis of pancreatic beta cells

  9. Role of growth factors in control of pancreatic beta cell mass: focus on betatrophin.

    Science.gov (United States)

    Levitsky, Lynne L; Ardestani, Goli; Rhoads, David B

    2014-08-01

    Betatrophin is a newly described hormone, which potently stimulates beta cell replication in mice. This discovery has engendered great hope that it could prove clinically important in the treatment of type 1 and type 2 diabetes. Betatrophin, a 198-amino acid protein secreted by liver and adipose tissue, stimulates growth of pancreatic beta cell mass in insulin-resistant mice. Betatrophin has previously been named RIFL, lipasin, and ANGPLT8, and its salutory effects on lipid metabolism have been described in mouse and human studies. Serum betatrophin levels in humans correlate with improved adipose tissue lipid storage and lower serum triglyceride levels in the fed state, but do not correlate with insulin resistance or carbohydrate tolerance in humans. Betatrophin has not yet been shown to have an effect on beta cell replication in human pancreatic islets. Many endocrine and paracrine factors, of which betatrophin is the newest described, increase beta cell mass in murine models. None of these factors, including betatrophin, have displayed the same activity in clinical studies. This may reflect a profound species difference in beta cell regeneration pathways in mice and humans.

  10. Expression of transient receptor potential ankyrin 1 (TRPA1 and its role in insulin release from rat pancreatic beta cells.

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    De-Shou Cao

    Full Text Available Several transient receptor potential (TRP channels are expressed in pancreatic beta cells and have been proposed to be involved in insulin secretion. However, the endogenous ligands for these channels are far from clear. Here, we demonstrate the expression of the transient receptor potential ankyrin 1 (TRPA1 ion channel in the pancreatic beta cells and its role in insulin release. TRPA1 is an attractive candidate for inducing insulin release because it is calcium permeable and is activated by molecules that are produced during oxidative glycolysis.Immunohistochemistry, RT-PCR, and Western blot techniques were used to determine the expression of TRPA1 channel. Ca²⁺ fluorescence imaging and electrophysiology (voltage- and current-clamp techniques were used to study the channel properties. TRPA1-mediated insulin release was determined using ELISA.TRPA1 is abundantly expressed in a rat pancreatic beta cell line and freshly isolated rat pancreatic beta cells, but not in pancreatic alpha cells. Activation of TRPA1 by allyl isothiocyanate (AITC, hydrogen peroxide (H₂O₂, 4-hydroxynonenal (4-HNE, and cyclopentenone prostaglandins (PGJ₂ and a novel agonist methylglyoxal (MG induces membrane current, depolarization, and Ca²⁺ influx leading to generation of action potentials in a pancreatic beta cell line and primary cultured pancreatic beta cells. Activation of TRPA1 by agonists stimulates insulin release in pancreatic beta cells that can be inhibited by TRPA1 antagonists such as HC030031 or AP-18 and by RNA interference. TRPA1-mediated insulin release is also observed in conditions of voltage-gated Na⁺ and Ca²⁺ channel blockade as well as ATP sensitive potassium (K(ATP channel activation.We propose that endogenous and exogenous ligands of TRPA1 cause Ca²⁺ influx and induce basal insulin release and that TRPA1-mediated depolarization acts synergistically with K(ATP channel blockade to facilitate insulin release.

  11. Activation of the transcription factor carbohydrate-responsive element-binding protein by glucose leads to increased pancreatic beta cell differentiation in rats.

    Science.gov (United States)

    Soggia, A; Flosseau, K; Ravassard, P; Szinnai, G; Scharfmann, R; Guillemain, G

    2012-10-01

    Pancreatic cell development is a tightly controlled process. Although information is available regarding the mesodermal signals that control pancreatic development, little is known about the role of environmental factors such as nutrients, including glucose, on pancreatic development. We previously showed that glucose and its metabolism through the hexosamine biosynthesis pathway (HBP) promote pancreatic endocrine cell differentiation. Here, we analysed the role of the transcription factor carbohydrate-responsive element-binding protein (ChREBP) in this process. This transcription factor is activated by glucose, and has been recently described as a target of the HBP. We used an in vitro bioassay in which pancreatic endocrine and exocrine cells develop from rat embryonic pancreas in a way that mimics in vivo pancreatic development. Using this model, gain-of-function and loss-of-function experiments were undertaken. ChREBP was produced in the endocrine lineage during pancreatic development, its abundance increasing with differentiation. When rat embryonic pancreases were cultured in the presence of glucose or xylitol, the production of ChREBP targets was induced. Concomitantly, beta cell differentiation was enhanced. On the other hand, when embryonic pancreases were cultured with inhibitors decreasing ChREBP activity or an adenovirus producing a dominant-negative ChREBP, beta cell differentiation was reduced, indicating that ChREBP activity was necessary for proper beta cell differentiation. Interestingly, adenovirus producing a dominant-negative ChREBP also reduced the positive effect of N-acetylglucosamine, a substrate of the HBP acting on beta cell differentiation. Our work supports the idea that glucose, through the transcription factor ChREBP, controls beta cell differentiation from pancreatic progenitors.

  12. CISH has no non-redundant functions in glucose homeostasis or beta cell proliferation during pregnancy in mice.

    Science.gov (United States)

    Jiao, Yang; Rieck, Sebastian; Le Lay, John; Kaestner, Klaus H

    2013-11-01

    Increased beta cell proliferation during pregnancy is mediated by the Janus kinase 2/signal transducer and activator of transcription 5 (JAK2/STAT5) signalling pathway in response to increased lactogen levels. Activation of the pathway leads to transcriptional upregulation of Cish (encoding cytokine-inducible SH2 domain-containing protein), a member of the suppressor of cytokine signalling (SOCS) family of genes, forming a negative-feedback loop. Here, we examined whether conditional gene ablation of Cish in the pancreas improves beta cell proliferation and beta cell function during pregnancy in mice. We derived mice with a novel, conditional loxP allele for Cish. Pancreas-specific ablation of Cish was achieved by crossing Cish (loxP/loxP) mice with Pdx1-Cre (Early) mice. Beta cell proliferation was quantified by BrdU labelling. Glucose homeostasis was examined with glucose tolerance tests and determination of plasma insulin levels. The expression of other Socs genes and target genes of p-STAT5 related to beta cell function and beta cell proliferation was determined by quantitative PCR. There was no difference in beta cell proliferation or glucose homeostasis between the Cish mutant group and the control group. The p-STAT5 protein level was the same in Cish mutant and control mice. Socs2 gene expression was higher in Cish mutant than control mice at pregnancy day 9.5. The expression of other Socs genes was the same between control and mutant mice. Our results show that CISH has no non-redundant functions in beta cell proliferation or glucose homeostasis during pregnancy in mice. Socs2 might compensate for the loss of Cish during pregnancy.

  13. Enhancing pancreatic Beta-cell regeneration in vivo with pioglitazone and alogliptin.

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    Hao Yin

    Full Text Available Pancreatic beta-cells retain limited ability to regenerate and proliferate after various physiologic triggers. Identifying therapies that are able to enhance beta-cell regeneration may therefore be useful for the treatment of both type 1 and type 2 diabetes.In this study we investigated endogenous and transplanted beta-cell regeneration by serially quantifying changes in bioluminescence from beta-cells from transgenic mice expressing firefly luciferase under the control of the mouse insulin I promoter. We tested the ability of pioglitazone and alogliptin, two drugs developed for the treatment of type 2 diabetes, to enhance beta-cell regeneration, and also defined the effect of the immunosuppression with rapamycin and tacrolimus on transplanted islet beta mass.Pioglitazone is a stimulator of nuclear receptor peroxisome proliferator-activated receptor gamma while alogliptin is a selective dipeptidyl peptidase IV inhibitor. Pioglitazone alone, or in combination with alogliptin, enhanced endogenous beta-cell regeneration in streptozotocin-treated mice, while alogliptin alone had modest effects. In a model of syngeneic islet transplantation, immunosuppression with rapamycin and tacrolimus induced an early loss of beta-cell mass, while treatment with insulin implants to maintain normoglycemia and pioglitazone plus alogliptin was able to partially promote beta-cell mass recovery.These data highlight the utility of bioluminescence for serially quantifying functional beta-cell mass in living mice. They also demonstrate the ability of pioglitazone, used either alone or in combination with alogliptin, to enhance regeneration of endogenous islet beta-cells as well as transplanted islets into recipients treated with rapamycin and tacrolimus.

  14. A Simple Matter of Life and Death—The Trials of Postnatal Beta-Cell Mass Regulation

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    Elena Tarabra

    2012-01-01

    Full Text Available Pancreatic beta-cells, which secrete the hormone insulin, are the key arbiters of glucose homeostasis. Defective beta-cell numbers and/or function underlie essentially all major forms of diabetes and must be restored if diabetes is to be cured. Thus, the identification of the molecular regulators of beta-cell mass and a better understanding of the processes of beta-cell differentiation and proliferation may provide further insight for the development of new therapeutic targets for diabetes. This review will focus on the principal hormones and nutrients, as well as downstream signalling pathways regulating beta-cell mass in the adult. Furthermore, we will also address more recently appreciated regulators of beta-cell mass, such as microRNAs.

  15. Restoring Mitochondrial Function: A Small Molecule-mediated Approach to Enhance Glucose Stimulated Insulin Secretion in Cholesterol Accumulated Pancreatic beta cells

    Science.gov (United States)

    Asalla, Suman; Girada, Shravan Babu; Kuna, Ramya S.; Chowdhury, Debabrata; Kandagatla, Bhaskar; Oruganti, Srinivas; Bhadra, Utpal; Bhadra, Manika Pal; Kalivendi, Shasi Vardhan; Rao, Swetha Pavani; Row, Anupama; Ibrahim, A.; Ghosh, Partha Pratim; Mitra, Prasenjit

    2016-06-01

    Dyslipidemia, particularly the elevated serum cholesterol levels, aggravate the pathophysiology of type 2 diabetes. In the present study we explored the relationship between fasting blood sugar and serum lipid parameters in human volunteers which revealed a significant linear effect of serum cholesterol on fasting blood glucose. Short term feeding of cholesterol enriched diet to rodent model resulted in elevated serum cholesterol levels, cholesterol accumulation in pancreatic islets and hyperinsulinemia with modest increase in plasma glucose level. To explore the mechanism, we treated cultured BRIN-BD11 pancreatic beta cells with soluble cholesterol. Our data shows that cholesterol treatment of cultured pancreatic beta cells enhances total cellular cholesterol. While one hour cholesterol exposure enhances insulin exocytosis, overnight cholesterol accumulation in cultured pancreatic beta cells affects cellular respiration, and inhibits Glucose stimulated insulin secretion. We further report that (E)-4-Chloro-2-(1-(2-(2,4,6-trichlorophenyl) hydrazono) ethyl) phenol (small molecule M1) prevents the cholesterol mediated blunting of cellular respiration and potentiates Glucose stimulated insulin secretion which was abolished in pancreatic beta cells on cholesterol accumulation.

  16. EPConDB: a web resource for gene expression related to pancreatic development, beta-cell function and diabetes.

    Science.gov (United States)

    Mazzarelli, Joan M; Brestelli, John; Gorski, Regina K; Liu, Junmin; Manduchi, Elisabetta; Pinney, Deborah F; Schug, Jonathan; White, Peter; Kaestner, Klaus H; Stoeckert, Christian J

    2007-01-01

    EPConDB (http://www.cbil.upenn.edu/EPConDB) is a public web site that supports research in diabetes, pancreatic development and beta-cell function by providing information about genes expressed in cells of the pancreas. EPConDB displays expression profiles for individual genes and information about transcripts, promoter elements and transcription factor binding sites. Gene expression results are obtained from studies examining tissue expression, pancreatic development and growth, differentiation of insulin-producing cells, islet or beta-cell injury, and genetic models of impaired beta-cell function. The expression datasets are derived using different microarray platforms, including the BCBC PancChips and Affymetrix gene expression arrays. Other datasets include semi-quantitative RT-PCR and MPSS expression studies. For selected microarray studies, lists of differentially expressed genes, derived from PaGE analysis, are displayed on the site. EPConDB provides database queries and tools to examine the relationship between a gene, its transcriptional regulation, protein function and expression in pancreatic tissues.

  17. The expression of dominant negative TCF7L2 in pancreatic beta cells during the embryonic stage causes impaired glucose homeostasis.

    Science.gov (United States)

    Shao, Weijuan; Xiong, Xiaoquan; Ip, Wilfred; Xu, Fenghao; Song, Zhuolun; Zeng, Kejing; Hernandez, Marcela; Liang, Tao; Weng, Jianping; Gaisano, Herbert; Nostro, M Cristina; Jin, Tianru

    2015-04-01

    Disruption of TCF7L2 in mouse pancreatic β-cells has generated different outcomes in several investigations. Here we aim to clarify role of β-cell TCF7L2 and Wnt signaling using a functional-knockdown approach. Adenovirus-mediated dominant negative TCF7L2 (TCF7L2DN) expression was conducted in Ins-1 cells. The fusion gene in which TCF7L2DN expression is driven by P TRE3G was utilized to generate the transgenic mouse line TCF7L2DN Tet . The double transgenic line was created by mating TCF7L2DN Tet with Ins2-rtTA, designated as βTCFDN. β-cell specific TCF7L2DN expression was induced in βTCFDN by doxycycline feeding. TCF7L2DN expression in Ins-1 cells reduced GSIS, cell proliferation and expression of a battery of genes including incretin receptors and β-cell transcription factors. Inducing TCF7L2DN expression in βTCFDN during adulthood or immediately after weaning generated no or very modest metabolic defect, while its expression during embryonic development by doxycycline feeding in pregnant mothers resulted in significant glucose intolerance associated with altered β-cell gene expression and reduced β-cell mass. Our observations support a cell autonomous role for TCF7L2 in pancreatic β-cells suggested by most, though not all, investigations. βTCFDN is a novel model for further exploring the role of TCF7L2 in β-cell genesis and metabolic homeostasis.

  18. Effect of iron on pancreatic beta cell function and insulin resistance ...

    African Journals Online (AJOL)

    Background: Increase in total body iron store has been reported in the aetiology and development of diabetes mellitus. The effect of iron supplementation in female with respect to the incidence of diabetes mellitus was investigated on the pancreatic beta cell function and insulin resistance in normal female rats. Methods: ...

  19. Transgenic overexpression of active calcineurin in beta-cells results in decreased beta-cell mass and hyperglycemia.

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    Ernesto Bernal-Mizrachi

    2010-08-01

    Full Text Available Glucose modulates beta-cell mass and function through an initial depolarization and Ca(2+ influx, which then triggers a number of growth regulating signaling pathways. One of the most important downstream effectors in Ca(2+ signaling is the calcium/Calmodulin activated serine threonine phosphatase, calcineurin. Recent evidence suggests that calcineurin/NFAT is essential for beta-cell proliferation, and that in its absence loss of beta-cells results in diabetes. We hypothesized that in contrast, activation of calcineurin might result in expansion of beta-cell mass and resistance to diabetes.To determine the role of activation of calcineurin signaling in the regulation of pancreatic beta-cell mass and proliferation, we created mice that expressed a constitutively active form of calcineurin under the insulin gene promoter (caCn(RIP. To our surprise, these mice exhibited glucose intolerance. In vitro studies demonstrated that while the second phase of Insulin secretion is enhanced, the overall insulin secretory response was conserved. Islet morphometric studies demonstrated decreased beta-cell mass suggesting that this was a major component responsible for altered Insulin secretion and glucose intolerance in caCn(RIP mice. The reduced beta-cell mass was accompanied by decreased proliferation and enhanced apoptosis.Our studies identify calcineurin as an important factor in controlling glucose homeostasis and indicate that chronic depolarization leading to increased calcineurin activity may contribute, along with other genetic and environmental factors, to beta-cell dysfunction and diabetes.

  20. SIRT6-mediated transcriptional suppression of Txnip is critical for pancreatic beta cell function and survival in mice.

    Science.gov (United States)

    Qin, Kunhua; Zhang, Ning; Zhang, Zhao; Nipper, Michael; Zhu, Zhenxin; Leighton, Jake; Xu, Kexin; Musi, Nicolas; Wang, Pei

    2018-04-01

    Better understanding of how genetic and epigenetic components control beta cell differentiation and function is key to the discovery of novel therapeutic approaches to prevent beta cell dysfunction and failure in the progression of type 2 diabetes. Our goal was to elucidate the role of histone deacetylase sirtuin 6 (SIRT6) in beta cell development and homeostasis. Sirt6 endocrine progenitor cell conditional knockout and beta cell-specific knockout mice were generated using the Cre-loxP system. Mice were assayed for islet morphology, glucose tolerance, glucose-stimulated insulin secretion and susceptibility to streptozotocin. Transcriptional regulatory functions of SIRT6 in primary islets were evaluated by RNA-Seq analysis. Reverse transcription-quantitative (RT-q)PCR and immunoblot were used to verify and investigate the gene expression changes. Chromatin occupancies of SIRT6, H3K9Ac, H3K56Ac and active RNA polymerase II were evaluated by chromatin immunoprecipitation. Deletion of Sirt6 in pancreatic endocrine progenitor cells did not affect endocrine morphology, beta cell mass or insulin production but did result in glucose intolerance and defective glucose-stimulated insulin secretion in mice. Conditional deletion of Sirt6 in adult beta cells reproduced the insulin secretion defect. Loss of Sirt6 resulted in aberrant upregulation of thioredoxin-interacting protein (TXNIP) in beta cells. SIRT6 deficiency led to increased acetylation of histone H3 lysine residue at 9 (H3K9Ac), acetylation of histone H3 lysine residue at 56 (H3K56Ac) and active RNA polymerase II at the promoter region of Txnip. SIRT6-deficient beta cells exhibited a time-dependent increase in H3K9Ac, H3K56Ac and TXNIP levels. Finally, beta cell-specific SIRT6-deficient mice showed increased sensitivity to streptozotocin. Our results reveal that SIRT6 suppresses Txnip expression in beta cells via deacetylation of histone H3 and plays a critical role in maintaining beta cell function and viability

  1. Maternal obesity accelerates fetal pancreatic beta-cell but not alpha-cell development in sheep: prenatal consequences.

    Science.gov (United States)

    Ford, Stephen P; Zhang, Liren; Zhu, Meijun; Miller, Myrna M; Smith, Derek T; Hess, Bret W; Moss, Gary E; Nathanielsz, Peter W; Nijland, Mark J

    2009-09-01

    Maternal obesity affects offspring weight, body composition, and organ function, increasing diabetes and metabolic syndrome risk. We determined effects of maternal obesity and a high-energy diet on fetal pancreatic development. Sixty days prior to breeding, ewes were assigned to control [100% of National Research Council (NRC) recommendations] or obesogenic (OB; 150% NRC) diets. At 75 days gestation, OB ewes exhibited elevated insulin-to-glucose ratios at rest and during a glucose tolerance test, demonstrating insulin resistance compared with control ewes. In fetal studies, ewes ate their respective diets from 60 days before to 75 days after conception when animals were euthanized under general anesthesia. OB and control ewes increased in body weight by approximately 43% and approximately 6%, respectively, from diet initiation until necropsy. Although all organs were heavier in fetuses from OB ewes, only pancreatic weight increased as a percentage of fetal weight. Blood glucose, insulin, and cortisol were elevated in OB ewes and fetuses on day 75. Insulin-positive cells per unit pancreatic area were 50% greater in fetuses from OB ewes as a result of increased beta-cell mitoses rather than decreased programmed cell death. Lambs of OB ewes were born earlier but weighed the same as control lambs; however, their crown-to-rump length was reduced, and their fat mass was increased. We conclude that increased systemic insulin in fetuses from OB ewes results from increased glucose exposure and/or cortisol-induced accelerated fetal beta-cell maturation and may contribute to premature beta-cell function loss and predisposition to obesity and metabolic disease in offspring.

  2. The effect of smoking cessation pharmacotherapies on pancreatic beta cell function

    International Nuclear Information System (INIS)

    Woynillowicz, Amanda K.; Raha, Sandeep; Nicholson, Catherine J.; Holloway, Alison C.

    2012-01-01

    The goal of our study was to evaluate whether drugs currently used for smoking cessation (i.e., nicotine replacement therapy, varenicline [a partial agonist at nicotinic acetylcholine receptors (nAChR)] and bupropion [which acts in part as a nAChR antagonist]) can affect beta cell function and determine the mechanism(s) of this effect. INS-1E cells, a rat beta cell line, were treated with nicotine, varenicline and bupropion to determine their effects on beta cell function, mitochondrial electron transport chain enzyme activity and cellular/oxidative stress. Treatment of INS-1E cells with equimolar concentrations (1 μM) of three test compounds resulted in an ablation of normal glucose-stimulated insulin secretion by the cells. This disruption of normal beta cell function was associated with mitochondrial dysfunction since all three compounds tested significantly decreased the activity of mitochondrial electron transport chain enzyme activity. These results raise the possibility that the currently available smoking cessation pharmacotherapies may also have adverse effects on beta cell function and thus glycemic control in vivo. Therefore whether or not the use of nicotine replacement therapy, varenicline and bupropion can cause endocrine changes which are consistent with impaired pancreatic function warrants further investigation. -- Highlights: ► Smoking cessation drugs have the potential to disrupt beta cell function in vitro. ► The effects of nicotine, varenicline and bupropion are similar. ► The impaired beta cell function is mediated by mitochondrial dysfunction. ► If similar effects are seen in vivo, these drugs may increase the risk of diabetes.

  3. The effect of smoking cessation pharmacotherapies on pancreatic beta cell function

    Energy Technology Data Exchange (ETDEWEB)

    Woynillowicz, Amanda K. [Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada); Raha, Sandeep [Department of Pediatrics, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada); Nicholson, Catherine J. [Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada); Holloway, Alison C., E-mail: hollow@mcmaster.ca [Department of Obstetrics and Gynecology, McMaster University, Hamilton, ON, Canada L8N 3Z5 (Canada)

    2012-11-15

    The goal of our study was to evaluate whether drugs currently used for smoking cessation (i.e., nicotine replacement therapy, varenicline [a partial agonist at nicotinic acetylcholine receptors (nAChR)] and bupropion [which acts in part as a nAChR antagonist]) can affect beta cell function and determine the mechanism(s) of this effect. INS-1E cells, a rat beta cell line, were treated with nicotine, varenicline and bupropion to determine their effects on beta cell function, mitochondrial electron transport chain enzyme activity and cellular/oxidative stress. Treatment of INS-1E cells with equimolar concentrations (1 μM) of three test compounds resulted in an ablation of normal glucose-stimulated insulin secretion by the cells. This disruption of normal beta cell function was associated with mitochondrial dysfunction since all three compounds tested significantly decreased the activity of mitochondrial electron transport chain enzyme activity. These results raise the possibility that the currently available smoking cessation pharmacotherapies may also have adverse effects on beta cell function and thus glycemic control in vivo. Therefore whether or not the use of nicotine replacement therapy, varenicline and bupropion can cause endocrine changes which are consistent with impaired pancreatic function warrants further investigation. -- Highlights: ► Smoking cessation drugs have the potential to disrupt beta cell function in vitro. ► The effects of nicotine, varenicline and bupropion are similar. ► The impaired beta cell function is mediated by mitochondrial dysfunction. ► If similar effects are seen in vivo, these drugs may increase the risk of diabetes.

  4. Regulation of Pancreatic Beta Cell Stimulus-Secretion Coupling by microRNAs

    Directory of Open Access Journals (Sweden)

    Jonathan L. S. Esguerra

    2014-11-01

    Full Text Available Increased blood glucose after a meal is countered by the subsequent increased release of the hypoglycemic hormone insulin from the pancreatic beta cells. The cascade of molecular events encompassing the initial sensing and transport of glucose into the beta cell, culminating with the exocytosis of the insulin large dense core granules (LDCVs is termed “stimulus-secretion coupling.” Impairment in any of the relevant processes leads to insufficient insulin release, which contributes to the development of type 2 diabetes (T2D. The fate of the beta cell, when exposed to environmental triggers of the disease, is determined by the possibility to adapt to the new situation by regulation of gene expression. As established factors of post-transcriptional regulation, microRNAs (miRNAs are well-recognized mediators of beta cell plasticity and adaptation. Here, we put focus on the importance of comprehending the transcriptional regulation of miRNAs, and how miRNAs are implicated in stimulus-secretion coupling, specifically those influencing the late stages of insulin secretion. We suggest that efficient beta cell adaptation requires an optimal balance between transcriptional regulation of miRNAs themselves, and miRNA-dependent gene regulation. The increased knowledge of the beta cell transcriptional network inclusive of non-coding RNAs such as miRNAs is essential in identifying novel targets for the treatment of T2D.

  5. Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

    Energy Technology Data Exchange (ETDEWEB)

    Pavlikova, Nela, E-mail: nela.pavlikova@lf3.cuni.cz [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Smetana, Pavel [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic); Halada, Petr [Laboratory of Molecular Structure Characterization, Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague (Czech Republic); Kovar, Jan [Department of Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Prague (Czech Republic)

    2015-10-15

    Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

  6. Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells

    International Nuclear Information System (INIS)

    Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

    2015-01-01

    Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. - Highlights: • Epidemiologic studies connect pollution with incidence of diabetes mellitus. • We explored the effect of DDT and DDE on protein expression in the NES2Y pancreatic beta cell line. • One month exposure to three sublethal concentrations of DDT and DDE was employed. • Expression of alpha-enolase, actin

  7. Chronic antidiabetic sulfonylureas in vivo: reversible effects on mouse pancreatic beta-cells.

    Directory of Open Access Journals (Sweden)

    Maria Sara Remedi

    2008-10-01

    Full Text Available Pancreatic beta-cell ATP-sensitive potassium (K ATP channels are critical links between nutrient metabolism and insulin secretion. In humans, reduced or absent beta-cell K ATP channel activity resulting from loss-of-function K ATP mutations induces insulin hypersecretion. Mice with reduced K ATP channel activity also demonstrate hyperinsulinism, but mice with complete loss of K ATP channels (K ATP knockout mice show an unexpected insulin undersecretory phenotype. Therefore we have proposed an "inverse U" hypothesis to explain the response to enhanced excitability, in which excessive hyperexcitability drives beta-cells to insulin secretory failure without cell death. Many patients with type 2 diabetes treated with antidiabetic sulfonylureas (which inhibit K ATP activity and thereby enhance insulin secretion show long-term insulin secretory failure, which we further suggest might reflect a similar progression.To test the above hypotheses, and to mechanistically investigate the consequences of prolonged hyperexcitability in vivo, we used a novel approach of implanting mice with slow-release sulfonylurea (glibenclamide pellets, to chronically inhibit beta-cell K ATP channels. Glibenclamide-implanted wild-type mice became progressively and consistently diabetic, with significantly (p < 0.05 reduced insulin secretion in response to glucose. After 1 wk of treatment, these mice were as glucose intolerant as adult K ATP knockout mice, and reduction of secretory capacity in freshly isolated islets from implanted animals was as significant (p < 0.05 as those from K ATP knockout animals. However, secretory capacity was fully restored in islets from sulfonylurea-treated mice within hours of drug washout and in vivo within 1 mo after glibenclamide treatment was terminated. Pancreatic immunostaining showed normal islet size and alpha-/beta-cell distribution within the islet, and TUNEL staining showed no evidence of apoptosis.These results demonstrate that

  8. Effect of atorvastatin on pancreatic Beta-cell function and insulin resistance in type 2 diabetes mellitus patients: a randomized pilot study.

    Science.gov (United States)

    Goyal, Aman; Singh, Surender; Tandon, Nikhil; Gupta, Nandita; Gupta, Yogendra Kumar

    2014-12-01

    Statins are commonly used for the management of dyslipidemia in type 2 diabetes mellitus patients. We hypothesized that atorvastatin could modulate the beta-cell function by altering the levels of proapoptotic and antiapoptotic lipoproteins and could also have an effect on insulin resistance. The aim of the present pilot study was to assess the effect of atorvastatin 10 mg on pancreatic beta-cell function and insulin resistance in patients with hyperlipidemia and type 2 diabetes by using the homeostasis model assessment-2 (HOMA2) index. Fifty-one type 2 diabetes patients receiving oral antidiabetes drugs, not taking statins, with baseline low-density lipoprotein cholesterol between 2.6 mmol/L and 4.1 mmol/L were included. Forty-three patients (21 in placebo group and 22 in atorvastatin group) completed the study and were taken up for final analysis. Fasting blood samples were obtained at baseline and at 12 weeks to determine levels of blood glucose, lipid profile, insulin, C-peptide and glycosylated hemoglobin (A1C). Atorvastatin nonsignificantly increased fasting serum insulin (+14.29%, p=0.18), accompanied by marginal nonsignificant increases in fasting plasma glucose and A1C. There was a decrease in HOMA2 percent beta-cell function (-2.9%, p=0.72) and increase in HOMA2 insulin resistance (+14%, p=0.16) in the atorvastatin group as compared with baseline, but the difference was not statistically significant. Atorvastatin in the dose used failed to produce significant change in pancreatic beta-cell function and insulin resistance in type 2 diabetes patients as assessed by the HOMA2 index. The possible explanations include absence of lipotoxicity at prevailing levels of dyslipidemia at baseline or inadequacy of statin dose used in the study. (Clinical Trials Registry-India: CTRI/2008/091/000099). Copyright © 2014 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

  9. The zinc transporter ZNT3 co-localizes with insulin in INS-1E pancreatic beta cells and influences cell survival, insulin secretion capacity, and ZNT8 expression

    DEFF Research Database (Denmark)

    Smidt, Kamille; Larsen, Agnete; Brønden, Andreas

    2016-01-01

    Zinc trafficking in pancreatic beta cells is tightly regulated by zinc transporting (ZNTs) proteins. The role of different ZNTs in the beta cells is currently being clarified. ZNT8 transports zinc into insulin granules and is critical for a correct insulin crystallization and storage in the granu......Zinc trafficking in pancreatic beta cells is tightly regulated by zinc transporting (ZNTs) proteins. The role of different ZNTs in the beta cells is currently being clarified. ZNT8 transports zinc into insulin granules and is critical for a correct insulin crystallization and storage...

  10. Effect of prolonged exposure to sublethal concentrations of DDT and DDE on protein expression in human pancreatic beta cells.

    Science.gov (United States)

    Pavlikova, Nela; Smetana, Pavel; Halada, Petr; Kovar, Jan

    2015-10-01

    Pollution of the environment represents one of less explored potential reasons for the worldwide epidemic of type 2 diabetes. One of the most prevalent organochlorine pollutants remains the pesticide DDT and its degradation product DDE. Despite some epidemiologic correlations between levels of DDT and DDE in human organism and the prevalence of diabetes, there is almost no information about the exact targets of these compounds inside pancreatic beta cells. To detect functional areas of pancreatic beta cells that could be affected by exposure to DDT and DDE, we analyzed changes in protein expression in the NES2Y human pancreatic beta cell line exposed to three sublethal concentrations (0.1 μM, 1 μM, 10 μM) of DDT and DDE for 1 month. Protein separation and identification was achieved using high-resolution 2D-electrophoresis, computer analysis and mass spectrometry. With these techniques, four proteins were found downregulated after exposure to 10 μM DDT: three cytoskeletal proteins (cytokeratin 8, cytokeratin 18 and actin) and one protein involved in glycolysis (alpha-enolase). Two proteins were downregulated after exposure to 10 μM DDE: cytokeratin 18 and heterogenous nuclear ribonucleoprotein H1 (HNRH1). These changes correlate with previously described effects of other stress conditions (e.g. exposure to palmitate, hyperglycemia, imidazoline derivative, and cytokines) on protein expression in pancreatic beta cells. We conclude that cytoskeletal proteins and their processing, glucose metabolism, and mRNA processing may represent targets affected by exposure to conditions hostile to pancreatic beta cells, including exposure to DDT and DDE. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Genetic models rule out a major role of beta cell glycogen in the control of glucose homeostasis.

    Science.gov (United States)

    Mir-Coll, Joan; Duran, Jordi; Slebe, Felipe; García-Rocha, Mar; Gomis, Ramon; Gasa, Rosa; Guinovart, Joan J

    2016-05-01

    Glycogen accumulation occurs in beta cells of diabetic patients and has been proposed to partly mediate glucotoxicity-induced beta cell dysfunction. However, the role of glycogen metabolism in beta cell function and its contribution to diabetes pathophysiology remain poorly understood. We investigated the function of beta cell glycogen by studying glucose homeostasis in mice with (1) defective glycogen synthesis in the pancreas; and (2) excessive glycogen accumulation in beta cells. Conditional deletion of the Gys1 gene and overexpression of protein targeting to glycogen (PTG) was accomplished by Cre-lox recombination using pancreas-specific Cre lines. Glucose homeostasis was assessed by determining fasting glycaemia, insulinaemia and glucose tolerance. Beta cell mass was determined by morphometry. Glycogen was detected histologically by periodic acid-Schiff's reagent staining. Isolated islets were used for the determination of glycogen and insulin content, insulin secretion, immunoblots and gene expression assays. Gys1 knockout (Gys1 (KO)) mice did not exhibit differences in glucose tolerance or basal glycaemia and insulinaemia relative to controls. Insulin secretion and gene expression in isolated islets was also indistinguishable between Gys1 (KO) and controls. Conversely, despite effective glycogen overaccumulation in islets, mice with PTG overexpression (PTG(OE)) presented similar glucose tolerance to controls. However, under fasting conditions they exhibited lower glycaemia and higher insulinaemia. Importantly, neither young nor aged PTG(OE) mice showed differences in beta cell mass relative to age-matched controls. Finally, a high-fat diet did not reveal a beta cell-autonomous phenotype in either model. Glycogen metabolism is not required for the maintenance of beta cell function. Glycogen accumulation in beta cells alone is not sufficient to trigger the dysfunction or loss of these cells, or progression to diabetes.

  12. Drp1 guarding of the mitochondrial network is important for glucose-stimulated insulin secretion in pancreatic beta cells

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Florian; Schultz, Julia; Waterstradt, Rica; Baltrusch, Simone, E-mail: simone.baltrusch@med.uni-rostock.de

    2016-06-10

    Mitochondria form a tubular network in mammalian cells, and the mitochondrial life cycle is determined by fission, fusion and autophagy. Dynamin-related protein 1 (Drp1) has a pivotal role in these processes because it alone is able to constrict mitochondria. However, the regulation and function of Drp1 have been shown to vary between cell types. Mitochondrial morphology affects mitochondrial metabolism and function. In pancreatic beta cells mitochondrial metabolism is a key component of the glucose-induced cascade of insulin secretion. The goal of the present study was to investigate the action of Drp1 in pancreatic beta cells. For this purpose Drp1 was down-regulated by means of shDrp1 in insulin-secreting INS1 cells and mouse pancreatic islets. In INS1 cells reduced Drp1 expression resulted in diminished expression of proteins regulating mitochondrial fusion, namely mitofusin 1 and 2, and optic atrophy protein 1. Diminished mitochondrial dynamics can therefore be assumed. After down-regulation of Drp1 in INS1 cells and spread mouse islets the initially homogenous mitochondrial network characterised by a moderate level of interconnections shifted towards high heterogeneity with elongated, clustered and looped mitochondria. These morphological changes were found to correlate directly with functional alterations. Mitochondrial membrane potential and ATP generation were significantly reduced in INS1 cells after Drp1down-regulation. Finally, a significant loss of glucose-stimulated insulin secretion was demonstrated in INS1 cells and mouse pancreatic islets. In conclusion, Drp1 expression is important in pancreatic beta cells to maintain the regulation of insulin secretion. -- Highlights: •Down-regulation of Drp1 in INS1 cells reduces mitochondrial fusion protein expression. •Mitochondrial membrane potential in INS1 cells is diminished after Drp1 down-regulation. •Mitochondria become elongated after down-regulation of Drp1 in beta cells. •Down-regulation of

  13. Intracellular serotonin modulates insulin secretion from pancreatic beta-cells by protein serotonylation.

    Directory of Open Access Journals (Sweden)

    Nils Paulmann

    2009-10-01

    Full Text Available While serotonin (5-HT co-localization with insulin in granules of pancreatic beta-cells was demonstrated more than three decades ago, its physiological role in the etiology of diabetes is still unclear. We combined biochemical and electrophysiological analyses of mice selectively deficient in peripheral tryptophan hydroxylase (Tph1-/- and 5-HT to show that intracellular 5-HT regulates insulin secretion. We found that these mice are diabetic and have an impaired insulin secretion due to the lack of 5-HT in the pancreas. The pharmacological restoration of peripheral 5-HT levels rescued the impaired insulin secretion in vivo. These findings were further evidenced by patch clamp experiments with isolated Tph1-/- beta-cells, which clearly showed that the secretory defect is downstream of Ca(2+-signaling and can be rescued by direct intracellular application of 5-HT via the clamp pipette. In elucidating the underlying mechanism further, we demonstrate the covalent coupling of 5-HT by transglutaminases during insulin exocytosis to two key players in insulin secretion, the small GTPases Rab3a and Rab27a. This renders them constitutively active in a receptor-independent signaling mechanism we have recently termed serotonylation. Concordantly, an inhibition of such activating serotonylation in beta-cells abates insulin secretion. We also observed inactivation of serotonylated Rab3a by enhanced proteasomal degradation, which is in line with the inactivation of other serotonylated GTPases. Our results demonstrate that 5-HT regulates insulin secretion by serotonylation of GTPases within pancreatic beta-cells and suggest that intracellular 5-HT functions in various microenvironments via this mechanism in concert with the known receptor-mediated signaling.

  14. Activation of the Wnt/β-catenin pathway in pancreatic beta cells during the compensatory islet hyperplasia in prediabetic mice

    International Nuclear Information System (INIS)

    Maschio, D.A.; Oliveira, R.B.; Santos, M.R.; Carvalho, C.P.F.; Barbosa-Sampaio, H.C.L.; Collares-Buzato, C.B.

    2016-01-01

    The Wnt/β-catenin signaling pathway, also known as the canonical Wnt pathway, plays a role in cell proliferation and differentiation in several tissues/organs. It has been recently described in humans a relationship between type 2 diabetes (T2DM) and mutation in the gene encoding the transcription factor TCF7L2 associated to the Wnt/β-catenin pathway. In the present study, we demonstrated that hyperplastic pancreatic islets from prediabetic mice fed a high-fat diet (HFD) for 60 d displayed nuclear translocation of active β-catenin associated with significant increases in protein content and gene expression of β-catenin as well as of cyclins D1, D2 and c-Myc (target genes of the Wnt pathway) but not of Tcf7l2 (the transcription factor). Meanwhile, these alterations were not observed in pancreatic islets from 30 d HFD-fed mice, that do not display significant beta cell hyperplasia. These data suggest that the Wnt/β-catenin pathway is activated in pancreatic islets during prediabetes and may play a role in the induction of the compensatory beta cell hyperplasia observed at early phase of T2DM. - Highlights: • Exposure to high-fat diet for 60 days induced prediabetes and beta cell mass expansion. • Hyperplastic pancreatic islets displayed nuclear translocation of active β-catenin. • Hyperplastic islets showed increased expression of target genes of the Wnt/β-catenin pathway. • Wnt/β-catenin pathway is activated during compensatory beta cell hyperplasia in mice.

  15. In silico identification of NF-kappaB-regulated genes in pancreatic beta-cells

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    Eizirik Decio L

    2007-02-01

    Full Text Available Abstract Background Pancreatic beta-cells are the target of an autoimmune attack in type 1 diabetes mellitus (T1DM. This is mediated in part by cytokines, such as interleukin (IL-1β and interferon (IFN-γ. These cytokines modify the expression of hundreds of genes, leading to beta-cell dysfunction and death by apoptosis. Several of these cytokine-induced genes are potentially regulated by the IL-1β-activated transcription factor (TF nuclear factor (NF-κB, and previous studies by our group have shown that cytokine-induced NF-κB activation is pro-apoptotic in beta-cells. To identify NF-κB-regulated gene networks in beta-cells we presently used a discriminant analysis-based approach to predict NF-κB responding genes on the basis of putative regulatory elements. Results The performance of linear and quadratic discriminant analysis (LDA, QDA in identifying NF-κB-responding genes was examined on a dataset of 240 positive and negative examples of NF-κB regulation, using stratified cross-validation with an internal leave-one-out cross-validation (LOOCV loop for automated feature selection and noise reduction. LDA performed slightly better than QDA, achieving 61% sensitivity, 91% specificity and 87% positive predictive value, and allowing the identification of 231, 251 and 580 NF-κB putative target genes in insulin-producing INS-1E cells, primary rat beta-cells and human pancreatic islets, respectively. Predicted NF-κB targets had a significant enrichment in genes regulated by cytokines (IL-1β or IL-1β + IFN-γ and double stranded RNA (dsRNA, as compared to genes not regulated by these NF-κB-dependent stimuli. We increased the confidence of the predictions by selecting only evolutionary stable genes, i.e. genes with homologs predicted as NF-κB targets in rat, mouse, human and chimpanzee. Conclusion The present in silico analysis allowed us to identify novel regulatory targets of NF-κB using a supervised classification method based on

  16. PARP-1 and YY1 are important novel regulators of CXCL12 gene transcription in rat pancreatic beta cells.

    Directory of Open Access Journals (Sweden)

    Jelena Marković

    Full Text Available Despite significant progress, the molecular mechanisms responsible for pancreatic beta cell depletion and development of diabetes remain poorly defined. At present, there is no preventive measure against diabetes. The positive impact of CXCL12 expression on the pancreatic beta cell prosurvival phenotype initiated this study. Our aim was to provide novel insight into the regulation of rat CXCL12 gene (Cxcl12 transcription. The roles of poly(ADP-ribose polymerase-1 (PARP-1 and transcription factor Yin Yang 1 (YY1 in Cxcl12 transcription were studied by examining their in vitro and in vivo binding affinities for the Cxcl12 promoter in a pancreatic beta cell line by the electrophoretic mobility shift assay and chromatin immunoprecipitation. The regulatory activities of PARP-1 and YY1 were assessed in transfection experiments using a reporter vector with a Cxcl12 promoter sequence driving luciferase gene expression. Experimental evidence for PARP-1 and YY1 revealed their trans-acting potential, wherein PARP-1 displayed an inhibitory, and YY1 a strong activating effect on Cxcl12 transcription. Streptozotocin (STZ-induced general toxicity in pancreatic beta cells was followed by changes in Cxcl12 promoter regulation. PARP-1 binding to the Cxcl12 promoter during basal and in STZ-compromised conditions led us to conclude that PARP-1 regulates constitutive Cxcl12 expression. During the early stage of oxidative stress, YY1 exhibited less affinity toward the Cxcl12 promoter while PARP-1 displayed strong binding. These interactions were accompanied by Cxcl12 downregulation. In the later stages of oxidative stress and intensive pancreatic beta cell injury, YY1 was highly expressed and firmly bound to Cxcl12 promoter in contrast to PARP-1. These interactions resulted in higher Cxcl12 expression. The observed ability of PARP-1 to downregulate, and of YY1 to upregulate Cxcl12 promoter activity anticipates corresponding effects in the natural context where the

  17. Nuclear import of glucokinase in pancreatic beta-cells is mediated by a nuclear localization signal and modulated by SUMOylation.

    Science.gov (United States)

    Johansson, Bente Berg; Fjeld, Karianne; Solheim, Marie Holm; Shirakawa, Jun; Zhang, Enming; Keindl, Magdalena; Hu, Jiang; Lindqvist, Andreas; Døskeland, Anne; Mellgren, Gunnar; Flatmark, Torgeir; Njølstad, Pål Rasmus; Kulkarni, Rohit N; Wierup, Nils; Aukrust, Ingvild; Bjørkhaug, Lise

    2017-10-15

    The localization of glucokinase in pancreatic beta-cell nuclei is a controversial issue. Although previous reports suggest such a localization, the mechanism for its import has so far not been identified. Using immunofluorescence, subcellular fractionation and mass spectrometry, we present evidence in support of glucokinase localization in beta-cell nuclei of human and mouse pancreatic sections, as well as in human and mouse isolated islets, and murine MIN6 cells. We have identified a conserved, seven-residue nuclear localization signal ( 30 LKKVMRR 36 ) in the human enzyme. Substituting the residues KK 31,32 and RR 35,36 with AA led to a loss of its nuclear localization in transfected cells. Furthermore, our data indicates that SUMOylation of glucokinase modulates its nuclear import, while high glucose concentrations do not significantly alter the enzyme nuclear/cytosolic ratio. Thus, for the first time, we provide data in support of a nuclear import of glucokinase mediated by a redundant mechanism, involving a nuclear localization signal, and which is modulated by its SUMOylation. These findings add new knowledge to the functional role of glucokinase in the pancreatic beta-cell. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Is serum zinc associated with pancreatic beta cell function and insulin sensitivity in pre-diabetic and normal individuals? Findings from the Hunter Community Study.

    Directory of Open Access Journals (Sweden)

    Khanrin P Vashum

    Full Text Available AIM: To determine if there is a difference in serum zinc concentration between normoglycaemic, pre-diabetic and type-2 diabetic groups and if this is associated with pancreatic beta cell function and insulin sensitivity in the former 2 groups. METHOD: Cross sectional study of a random sample of older community-dwelling men and women in Newcastle, New South Wales, Australia. Beta cell function, insulin sensitivity and insulin resistance were calculated for normoglycaemic and prediabetes participants using the Homeostasis Model Assessment (HOMA-2 calculator. RESULT: A total of 452 participants were recruited for this study. Approximately 33% (N = 149 had diabetes, 33% (N = 151 had prediabetes and 34% (N = 152 were normoglycaemic. Homeostasis Model Assessment (HOMA parameters were found to be significantly different between normoglycaemic and prediabetes groups (p<0.001. In adjusted linear regression, higher serum zinc concentration was associated with increased insulin sensitivity (p = 0.01 in the prediabetic group. There was also a significant association between smoking and worse insulin sensitivity. CONCLUSION: Higher serum zinc concentration is associated with increased insulin sensitivity. Longitudinal studies are required to determine if low serum zinc concentration plays a role in progression from pre-diabetes to diabetes.

  19. Deletion of glutamate dehydrogenase in beta-cells abolishes part of the insulin secretory response not required for glucose homeostasis

    DEFF Research Database (Denmark)

    Carobbio, Stefania; Frigerio, Francesca; Rubi, Blanca

    2009-01-01

    Insulin exocytosis is regulated in pancreatic ss-cells by a cascade of intracellular signals translating glucose levels into corresponding secretory responses. The mitochondrial enzyme glutamate dehydrogenase (GDH) is regarded as a major player in this process, although its abrogation has not been...... tested yet in animal models. Here, we generated transgenic mice, named betaGlud1(-/-), with ss-cell-specific GDH deletion. Our results show that GDH plays an essential role in the full development of the insulin secretory response. In situ pancreatic perfusion revealed that glucose-stimulated insulin...... secretion was reduced by 37% in betaGlud1(-/-). Furthermore, isolated islets with either constitutive or acute adenovirus-mediated knock-out of GDH showed a 49 and 38% reduction in glucose-induced insulin release, respectively. Adenovirus-mediated re-expression of GDH in betaGlud1(-/-) islets fully restored...

  20. Islet-selectivity of G-protein coupled receptor ligands evaluated for PET imaging of pancreatic {beta}-cell mass

    Energy Technology Data Exchange (ETDEWEB)

    Cline, Gary W., E-mail: gary.cline@yale.edu [Yale University School of Medicine (United States); Zhao, Xiaojian [Yale University School of Medicine (United States); Jakowski, Amy B.; Soeller, Walter C.; Treadway, Judith L. [Pfizer Global Research and Development, Pfizer Inc., Groton CT (United States)

    2011-09-02

    Highlights: {yields} We screened G-protein coupled receptors for imaging pancreatic. {yields} Database mining and immunohistochemistry identified GPCRs enriched in {beta}-cells. {yields} In vitro and in vivo assays were used to determine exocrine vs endocrine specificity. {yields} GPCR candidates for imaging of {beta}-cell mass are Prokineticin-1R, mGluR5, and GLP-1R. -- Abstract: A critical unmet need exists for methods to quantitatively measure endogenous pancreatic {beta}-cell mass (BCM) for the clinical evaluation of therapies to prevent or reverse loss of BCM and diabetes progression. Our objective was to identify G-protein coupled receptors (GPCRs) that are expressed with a high degree of specificity to islet {beta}-cells for receptor-targeted imaging of BCM. GPCRs enriched in pancreatic islets relative to pancreas acinar and hepatic tissue were identified using a database screen. Islet-specific expression was confirmed by human pancreas immunohistochemistry (IHC). In vitro selectivity assessment was determined from the binding and uptake of radiolabeled ligands to the rat insulinoma INS-1 832/13 cell line and isolated rat islets relative to the exocrine pancreas cell-type, PANC-1. Tail-vein injections of radioligands into rats were used to determine favorable image criteria of in vivo biodistribution to the pancreas relative to other internal organs (i.e., liver, spleen, stomach, and lungs). Database and IHC screening identified four candidate receptors for further in vitro and in vivo evaluation for PET imaging of BCM: prokineticin-1 receptor (PK-1R), metabotropic glutamate receptor type-5 (mGluR5), neuropeptide Y-2 receptor (NPY-2R), and glucagon-like peptide 1 receptor (GLP-1R). In vitro specificity ratios gave the following receptor rank order: PK-1R > GLP-1R > NPY-2R > mGluR5. The biodistribution rank order of selectivity to the pancreas was found to be PK-1R > VMAT2 {approx} GLP-1R > mGluR5. Favorable islet selectivity and biodistribution

  1. Development of biomarker specific of pancreatic beta cells (incretin radiolabelled) for image of beta functional mass in diabetic and obese: study in animal model

    International Nuclear Information System (INIS)

    Seo, Daniele

    2017-01-01

    Increased prevalence of obesity worldwide, has become a vast concern, stimulating investigations focusing prevention and therapy of this condition. The association of type 2 diabetes or insulin resistance aggravates the prognosis of obesity. Even patients successfully submitted to bariatric or metabolic surgery, may not be cured of diabetes, as improvement of circulating values of glucose and insulin not necessarily reflects recovery of pancreatic beta cell mass. There is no consensus about how to estimate beta cell mass in vivo. Available tools suffer from low sensitivity and specificity, often being as well cumbersome and expensive. Radiolabeled incretins, such as glucagon-like-peptide 1 (GLP-1) analogs, seem to be promising options for the measurement of beta cell mass in diabetes and insulinoma. The objective of this study was the development of two conjugates of GLP-1 analog, radiolabeled with 99m Technetium, as a noninvasive imaging method for the estimation of pancreatic beta cell mass, in the presence of obesity. Animal models were selected, including hyperlipidic diet-induced obesity, diet restricted obesity, and as controls, alloxan diabetes. Results indicated that both radiotracers achieved over 97% radiochemical yield. The most successful product was 99m Tc-HYNIC-βAla-Exendin-4. Low beta cell mass uptake occurred in diet-induced obesity. Diet-restricted obesity, with substantial shedding of excess body weight, was followed by remarkable decrease of fasting blood glucose, however beta cell mass uptake was only mildly improved. Future studies are recommended in obesity, type 2 diabetes, and dieting, including bariatric and metabolic operations. (author)

  2. Increased androgen levels in rats impair glucose-stimulated insulin secretion through disruption of pancreatic beta cell mitochondrial function.

    Science.gov (United States)

    Wang, Hongdong; Wang, Xiaping; Zhu, Yunxia; Chen, Fang; Sun, Yujie; Han, Xiao

    2015-11-01

    Although insulin resistance is recognized to contribute to the reproductive and metabolic phenotypes of polycystic ovary syndrome (PCOS), pancreatic beta cell dysfunction plays an essential role in the progression from PCOS to the development of type 2 diabetes. However, the role of insulin secretory abnormalities in PCOS has received little attention. In addition, the precise changes in beta cells and the underlying mechanisms remain unclear. In this study, we therefore attempted to elucidate potential mechanisms involved in beta cell alterations in a rat model of PCOS. Glucose-induced insulin secretion was measured in islets isolated from DHT-treated and control rats. Oxygen consumption rate (OCR), ATP production, and mitochondrial copy number were assayed to evaluate mitochondrial function. Glucose-stimulated insulin secretion is significantly decreased in islets from DHT-treated rats. On the other hand, significant reductions are observed in the expression levels of several key genes involved in mitochondrial biogenesis and in mitochondrial OCR and ATP production in DHT-treated rat islets. Meanwhile, we found that androgens can directly impair beta cell function by inducing mitochondrial dysfunction in vitro in an androgen receptor dependent manner. For the first time, our study demonstrates that increased androgens in female rats can impair glucose-stimulated insulin secretion partly through disruption of pancreatic beta cell mitochondrial function. This work has significance for hyperandrogenic women with PCOS: excess activation of the androgen receptor by androgens may provoke beta cell dysfunction via mitochondrial dysfunction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Clusters of conserved beta cell marker genes for assessment of beta cell phenotype

    DEFF Research Database (Denmark)

    Martens, Geert A; Jiang, Lei; Hellemans, Karine H

    2011-01-01

    The aim of this study was to establish a gene expression blueprint of pancreatic beta cells conserved from rodents to humans and to evaluate its applicability to assess shifts in the beta cell differentiated state. Genome-wide mRNA expression profiles of isolated beta cells were compared to those...... of a large panel of other tissue and cell types, and transcripts with beta cell-abundant and -selective expression were identified. Iteration of this analysis in mouse, rat and human tissues generated a panel of conserved beta cell biomarkers. This panel was then used to compare isolated versus laser capture...... microdissected beta cells, monitor adaptations of the beta cell phenotype to fasting, and retrieve possible conserved transcriptional regulators....

  4. Vanadyl Sulfate Treatment Stimulates Proliferation and Regeneration of Beta Cells in Pancreatic Islets

    Directory of Open Access Journals (Sweden)

    Samira Missaoui

    2014-01-01

    Full Text Available We examined the effects of vanadium sulfate (VOSO4 treatment at 5 and 10 mg/kg for 30 days on endocrine pancreas activity and histology in nondiabetic and STZ-induced diabetic rats. In diabetic group, blood glucose levels significantly increased while insulinemia level markedly decreased. At the end of treatment, VOSO4 at a dose of 10 mg/Kg normalized blood glucose level in diabetic group, restored insulinemia, and significantly improved insulin sensitivity. VOSO4 also increased in a dose-dependent manner the number of insulin immunopositive beta cells in pancreatic islets of nondiabetic rats. Furthermore, in the STZ-diabetic group, the decrease in the number of insulin immunopositive beta cells was corrected to reach the control level mainly with the higher dose of vanadium. Therefore, VOSO4 treatment normalized plasma glucose and insulin levels and improved insulin sensitivity in STZ-experimental diabetes and induced beta cells proliferation and/or regeneration in normal or diabetic rats.

  5. Clusters of conserved beta cell marker genes for assessment of beta cell phenotype

    DEFF Research Database (Denmark)

    Martens, Geert A; Jiang, Lei; Hellemans, Karine H

    2011-01-01

    The aim of this study was to establish a gene expression blueprint of pancreatic beta cells conserved from rodents to humans and to evaluate its applicability to assess shifts in the beta cell differentiated state. Genome-wide mRNA expression profiles of isolated beta cells were compared to those...... of a large panel of other tissue and cell types, and transcripts with beta cell-abundant and -selective expression were identified. Iteration of this analysis in mouse, rat and human tissues generated a panel of conserved beta cell biomarkers. This panel was then used to compare isolated versus laser capture...

  6. STAT5 activity in pancreatic beta-cells influences the severity of diabetes in animal models of type 1 and 2 diabetes

    DEFF Research Database (Denmark)

    Jackerott, Malene; Møldrup, Annette; Thams, Peter

    2006-01-01

    Pancreatic beta-cell growth and survival and insulin production are stimulated by growth hormone and prolactin through activation of the transcription factor signal transducer and activator of transcription (STAT)5. To assess the role of STAT5 activity in beta-cells in vivo, we generated transgen...... and type 2 diabetes....... reduced beta-cell proliferation at 6 months of age. The inhibitory effect of high-fat diet or leptin on insulin secretion was diminished in isolated islets from RIP-DNSTAT5 mice compared with wild-type islets. Upon multiple low-dose streptozotocin treatment, RIP-DNSTAT5 mice exhibited higher plasma...... of glucose tolerance, whereas RIP-CASTAT5 mice were more glucose tolerant and less hyperleptinemic than wild-type mice. Although the pancreatic insulin content and relative beta-cell area were increased in high-fat diet-fed RIP-DNSTAT5 mice compared with wild-type or RIP-CASTAT5 mice, RIP-DNSTAT5 mice showed...

  7. Effects of ethanol on pancreatic beta-cell death: interaction with glucose and fatty acids.

    Science.gov (United States)

    Dembele, Korami; Nguyen, K Hoa; Hernandez, Tiffany A; Nyomba, B L Grégoire

    2009-04-01

    Western lifestyle plays an important role in the prevalence of type 2 diabetes by causing insulin resistance and pancreatic beta-cell dysfunction, a prerequisite for the development of diabetes. High fat diet and alcohol are major components of the western diet. The aim of the present study was to investigate the effects of ethanol and fatty acids on beta-cell survival and metabolism. We treated the rat beta-cell line RINm5F with ethanol, a mixture of palmitic and oleic acids, or both. Reactive oxygen species (ROS) were determined by (5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate) (CM-H2DCFDA) fluorescence assay, and mitochondrial activity was assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) reduction assay and by determining ATP production. Cell viability was assessed with a cell counter and trypan blue exclusion, and the mode of cell death by Hoechst33342 and propidium iodide staining. With both ethanol and fatty acid treatments, MTT reduction and ATP production decreased, whereas ROS production increased. Ethanol treatment had no effect on cell number, whereas fatty acid treatment reduced the cell number. Cell incubation with ethanol, fatty acids, or both increased the number of Hoechst 33342-positive nuclei. However, the majority of nuclei from fatty acid-treated cells were stained with propidium iodide, indicating a loss of plasma membrane integrity. We conclude that both ethanol and fatty acids generate cellular oxidative stress, and affect mitochondrial function in RINm5F beta-cells. However, ethanol causes beta-cell death by apoptosis, whereas fatty acids cause cell death predominantly by necrosis. It is not known whether these results are applicable to human beta-cells.

  8. Involvement of interleukin 1 and interleukin 1 antagonist in pancreatic beta-cell destruction in insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Mandrup-Poulsen, T; Zumsteg, U; Reimers, J

    1993-01-01

    In this review we propose that the balance between the action of interleukin 1 (IL-1) and its natural antagonist IL-1ra on the level of the insulin-producing pancreatic beta-cell may play a decisive role in the pathogenesis of insulin-dependent diabetes mellitus (IDDM). We argue that IL-1...... potentiated by other cytokines (tumor necrosis factor alpha, interferon gamma) is an important effector molecule involved in both early and late events in the immune-mediated process that leads to beta-cell destruction and IDDM. We also point out that surprisingly high molar excesses of IL-1ra over IL-1...... are necessary to block the action of IL-1 on islet beta-cells compared to islet alpha-cells in vitro and in animals. We suggest that the selectivity of beta-cell destruction in IDDM may be conferred on several levels: (1) homing of beta-cell antigen specific T cells, (2) targeted delivery of cytokines...

  9. Pathway decision-making strategies for generating pancreatic beta-cells: systems biology or hit and miss?

    Science.gov (United States)

    Jensen, Jan

    2007-08-01

    Method selection strategies to achieve beta-cell differentiation from human embryonic stem cells are reviewed. Expectations are high for an embryonic stem cell derived cellular replacement method to cure diabetes, and recent observations indicate that mature beta-cells can be derived from human embryonic stem cells. In terms of the translational setting, however, we are not there yet; conversion of embryonic stem cells to fully mature beta-cells is not effective and does not provide an exclusive beta-cell population as the end-product. Studies emphasize that expecting development of a 'magic media bullet' that promotes endocrine fate is rather optimistic; consecutive administration of signaling inducers, carefully provided to mimic normal development, is more likely to succeed. To accomplish this task we need better understanding of the extracellular signaling pathways that drive progressive endodermal fate choices throughout development. Knowledge of cell-intrinsic control of fate assignments in pancreas is growing rapidly. Nevertheless, insufficient information regarding morphogen codes that operate in endoderm and pancreas is hindering development of better, directed differentiation schema of uncommitted embryonic stem cells toward endodermal, pancreatic, and subsequent endocrine specific fates. A systematic approach to defining morphogen codes in developing endoderm and pancreas appears timely and justified.

  10. Antioxidant and regulatory role of mitochondrial uncoupling protein UCP2 in pancreatic beta-cells

    Czech Academy of Sciences Publication Activity Database

    Ježek, Petr; Olejár, Tomáš; Smolková, Katarína; Ježek, Jan; Dlasková, Andrea; Plecitá-Hlavatá, Lydie; Zelenka, Jaroslav; Špaček, Tomáš; Engstová, Hana; Reguera Pajuelo, David; Jabůrek, Martin

    2014-01-01

    Roč. 63, Suppl.1 (2014), S73-S91 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GAP302/10/0346; GA ČR(CZ) GAP305/12/1247; GA ČR(CZ) GPP304/10/P204; GA MŠk(CZ) EE2.3.30.0025 Institutional support: RVO:67985823 Keywords : mitochondria * uncoupling protein UCP2 * pancreatic beta-cells * reactive oxygen species * glucose-stimulated insulin secretion Subject RIV: EA - Cell Biology Impact factor: 1.293, year: 2014

  11. EX4 stabilizes and activates Nrf2 via PKCδ, contributing to the prevention of oxidative stress-induced pancreatic beta cell damage

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi-Hwi; Kim, Eung-Hwi [College of Pharmacy, Gachon Institute of Pharmaceutical Science, Gachon University, Yeonsu-ku, Incheon (Korea, Republic of); Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Yeonsu-ku, Incheon (Korea, Republic of); Jung, Hye Seung [Department of Internal Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Yang, Dongki [Department of Physiology, Gachon University College of Medicine, Incheon (Korea, Republic of); Park, Eun-Young, E-mail: parkey@mokpo.ac.kr [College of Pharmacy, Natural Medicine Research Institute, Mokpo National University, Muan-gun, Jeonnam (Korea, Republic of); Jun, Hee-Sook, E-mail: hsjun@gachon.ac.kr [College of Pharmacy, Gachon Institute of Pharmaceutical Science, Gachon University, Yeonsu-ku, Incheon (Korea, Republic of); Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Yeonsu-ku, Incheon (Korea, Republic of); Gachon Medical Research Institute, Gil Hospital, Incheon (Korea, Republic of)

    2017-01-15

    Oxidative stress in pancreatic beta cells can inhibit insulin secretion and promote apoptotic cell death. Exendin-4 (EX4), a glucagon-like peptide-1 receptor agonist, can suppress beta cell apoptosis, improve beta cell function and protect against oxidative damage. In this study, we investigated the molecular mechanisms for antioxidative effects of EX4 in pancreatic beta cells. INS-1 cells, a rat insulinoma cell line, were pretreated with EX4 and exposed to palmitate or H{sub 2}O{sub 2}. Reactive oxygen species (ROS) production, and glutathione and insulin secretion were measured. The mRNA and protein expression levels of antioxidant genes were examined. The level of nuclear factor erythroid 2-related factor 2 (Nrf2), its binding to antioxidant response element (ARE), and its ubiquination in the presence of EX4 were determined. The Nrf2 signaling pathway was determined using rottlerin (protein kinase [PK]Cδ inhibitor), H89 (PKA inhibitor) and LY294002 (phosphatidylinositide 3-kinase [PI3K] inhibitor). EX4 treatment decreased ROS production, recovered cellular glutathione levels and insulin secretion in the presence of oxidative stress in INS-1 cells. The expression levels of glutamate-cysteine ligase catalytic subunit and heme oxygenase-1 were increased by EX4 treatment. EX4 promoted Nrf2 translocation, ARE binding activity and enhanced stabilization of Nrf2 by inhibition of ubiquitination. Knockdown of Nrf2 abolished the effect of EX4 on increased insulin secretion. Inhibition of PKCδ attenuated Nrf2 translocation and antioxidative gene expression by EX4 treatment. We suggest that EX4 activates and stabilizes Nrf2 through PKCδ activation, contributing to the increase of antioxidant gene expression and consequently improving beta cell function in the presence of oxidative stress. - Highlights: • EX4 protects against oxidative stress-induced pancreatic beta cell dysfunction. • EX4 increases antioxidant gene expression. • Antioxidative effect of EX4 is

  12. EX4 stabilizes and activates Nrf2 via PKCδ, contributing to the prevention of oxidative stress-induced pancreatic beta cell damage

    International Nuclear Information System (INIS)

    Kim, Mi-Hwi; Kim, Eung-Hwi; Jung, Hye Seung; Yang, Dongki; Park, Eun-Young; Jun, Hee-Sook

    2017-01-01

    Oxidative stress in pancreatic beta cells can inhibit insulin secretion and promote apoptotic cell death. Exendin-4 (EX4), a glucagon-like peptide-1 receptor agonist, can suppress beta cell apoptosis, improve beta cell function and protect against oxidative damage. In this study, we investigated the molecular mechanisms for antioxidative effects of EX4 in pancreatic beta cells. INS-1 cells, a rat insulinoma cell line, were pretreated with EX4 and exposed to palmitate or H 2 O 2 . Reactive oxygen species (ROS) production, and glutathione and insulin secretion were measured. The mRNA and protein expression levels of antioxidant genes were examined. The level of nuclear factor erythroid 2-related factor 2 (Nrf2), its binding to antioxidant response element (ARE), and its ubiquination in the presence of EX4 were determined. The Nrf2 signaling pathway was determined using rottlerin (protein kinase [PK]Cδ inhibitor), H89 (PKA inhibitor) and LY294002 (phosphatidylinositide 3-kinase [PI3K] inhibitor). EX4 treatment decreased ROS production, recovered cellular glutathione levels and insulin secretion in the presence of oxidative stress in INS-1 cells. The expression levels of glutamate-cysteine ligase catalytic subunit and heme oxygenase-1 were increased by EX4 treatment. EX4 promoted Nrf2 translocation, ARE binding activity and enhanced stabilization of Nrf2 by inhibition of ubiquitination. Knockdown of Nrf2 abolished the effect of EX4 on increased insulin secretion. Inhibition of PKCδ attenuated Nrf2 translocation and antioxidative gene expression by EX4 treatment. We suggest that EX4 activates and stabilizes Nrf2 through PKCδ activation, contributing to the increase of antioxidant gene expression and consequently improving beta cell function in the presence of oxidative stress. - Highlights: • EX4 protects against oxidative stress-induced pancreatic beta cell dysfunction. • EX4 increases antioxidant gene expression. • Antioxidative effect of EX4 is mediated by

  13. Inter-domain tagging implicates caveolin-1 in insulin receptor trafficking and Erk signaling bias in pancreatic beta-cells

    Directory of Open Access Journals (Sweden)

    Tobias Boothe

    2016-05-01

    Full Text Available Objective: The role and mechanisms of insulin receptor internalization remain incompletely understood. Previous trafficking studies of insulin receptors involved fluorescent protein tagging at their termini, manipulations that may be expected to result in dysfunctional receptors. Our objective was to determine the trafficking route and molecular mechanisms of functional tagged insulin receptors and endogenous insulin receptors in pancreatic beta-cells. Methods: We generated functional insulin receptors tagged with pH-resistant fluorescent proteins between domains. Confocal, TIRF and STED imaging revealed a trafficking pattern of inter-domain tagged insulin receptors and endogenous insulin receptors detected with antibodies. Results: Surprisingly, interdomain-tagged and endogenous insulin receptors in beta-cells bypassed classical Rab5a- or Rab7-mediated endocytic routes. Instead, we found that removal of insulin receptors from the plasma membrane involved tyrosine-phosphorylated caveolin-1, prior to trafficking within flotillin-1-positive structures to lysosomes. Multiple methods of inhibiting caveolin-1 significantly reduced Erk activation in vitro or in vivo, while leaving Akt signaling mostly intact. Conclusions: We conclude that phosphorylated caveolin-1 plays a role in insulin receptor internalization towards lysosomes through flotillin-1-positive structures and that caveolin-1 helps bias physiological beta-cell insulin signaling towards Erk activation. Author Video: Author Video Watch what authors say about their articles Keywords: Insulin receptor internalization, Insulin resistance, Pancreatic islet beta-cells, Autocrine insulin signaling

  14. Sirt1 regulates insulin secretion by repressing UCP2 in pancreatic beta cells.

    Directory of Open Access Journals (Sweden)

    Laura Bordone

    2006-02-01

    Full Text Available Sir2 and insulin/IGF-1 are the major pathways that impinge upon aging in lower organisms. In Caenorhabditis elegans a possible genetic link between Sir2 and the insulin/IGF-1 pathway has been reported. Here we investigate such a link in mammals. We show that Sirt1 positively regulates insulin secretion in pancreatic beta cells. Sirt1 represses the uncoupling protein (UCP gene UCP2 by binding directly to the UCP2 promoter. In beta cell lines in which Sirt1 is reduced by SiRNA, UCP2 levels are elevated and insulin secretion is blunted. The up-regulation of UCP2 is associated with a failure of cells to increase ATP levels after glucose stimulation. Knockdown of UCP2 restores the ability to secrete insulin in cells with reduced Sirt1, showing that UCP2 causes the defect in glucose-stimulated insulin secretion. Food deprivation induces UCP2 in mouse pancreas, which may occur via a reduction in NAD (a derivative of niacin levels in the pancreas and down-regulation of Sirt1. Sirt1 knockout mice display constitutively high UCP2 expression. Our findings show that Sirt1 regulates UCP2 in beta cells to affect insulin secretion.

  15. Rising intracellular zinc by membrane depolarization and glucose in insulin-secreting clonal HIT-T15 beta cells.

    Science.gov (United States)

    Slepchenko, Kira G; Li, Yang V

    2012-01-01

    Zinc (Zn(2+)) appears to be intimately involved in insulin metabolism since insulin secretion is correlated with zinc secretion in response to glucose stimulation, but little is known about the regulation of zinc homeostasis in pancreatic beta-cells. This study set out to identify the intracellular zinc transient by imaging free cytosolic zinc in HIT-T15 beta-cells with fluorescent zinc indicators. We observed that membrane depolarization by KCl (30-60 mM) was able to induce a rapid increase in cytosolic concentration of zinc. Multiple zinc transients of similar magnitude were elicited during repeated stimulations. The amplitude of zinc responses was not affected by the removal of extracellular calcium or zinc. However, the half-time of the rising slope was significantly slower after removing extracellular zinc with zinc chelator CaEDTA, suggesting that extracellular zinc affect the initial rising phase of zinc response. Glucose (10 mM) induced substantial and progressive increases in intracellular zinc concentration in a similar way as KCl, with variation in the onset and the duration of zinc mobilization. It is known that the depolarization of beta-cell membrane is coupled with the secretion of insulin. Rising intracellular zinc concentration may act as a critical signaling factor in insulin metabolism of pancreatic beta-cells.

  16. The Role of Oxidative Stress and Hypoxia in Pancreatic Beta-Cell Dysfunction in Diabetes Mellitus.

    Science.gov (United States)

    Gerber, Philipp A; Rutter, Guy A

    2017-04-01

    Metabolic syndrome is a frequent precursor of type 2 diabetes mellitus (T2D), a disease that currently affects ∼8% of the adult population worldwide. Pancreatic beta-cell dysfunction and loss are central to the disease process, although understanding of the underlying molecular mechanisms is still fragmentary. Recent Advances: Oversupply of nutrients, including glucose and fatty acids, and the subsequent overstimulation of beta cells, are believed to be an important contributor to insulin secretory failure in T2D. Hypoxia has also recently been implicated in beta-cell damage. Accumulating evidence points to a role for oxidative stress in both processes. Although the production of reactive oxygen species (ROS) results from enhanced mitochondrial respiration during stimulation with glucose and other fuels, the expression of antioxidant defense genes is unusually low (or disallowed) in beta cells. Not all subjects with metabolic syndrome and hyperglycemia go on to develop full-blown diabetes, implying an important role in disease risk for gene-environment interactions. Possession of common risk alleles at the SLC30A8 locus, encoding the beta-cell granule zinc transporter ZnT8, may affect cytosolic Zn 2+ concentrations and thus susceptibility to hypoxia and oxidative stress. Loss of normal beta-cell function, rather than total mass, is increasingly considered to be the major driver for impaired insulin secretion in diabetes. Better understanding of the role of oxidative changes, its modulation by genes involved in disease risk, and effects on beta-cell identity may facilitate the development of new therapeutic strategies to this disease. Antioxid. Redox Signal. 26, 501-518.

  17. Islet Cells Serve as Cells of Origin of Pancreatic Gastrin-Positive Endocrine Tumors.

    Science.gov (United States)

    Bonnavion, Rémy; Teinturier, Romain; Jaafar, Rami; Ripoche, Doriane; Leteurtre, Emmanuelle; Chen, Yuan-Jia; Rehfeld, Jens F; Lepinasse, Florian; Hervieu, Valérie; Pattou, François; Vantyghem, Marie-Christine; Scoazec, Jean-Yves; Bertolino, Philippe; Zhang, Chang Xian

    2015-10-01

    The cells of origin of pancreatic gastrinomas remain an enigma, since no gastrin-expressing cells are found in the normal adult pancreas. It was proposed that the cellular origin of pancreatic gastrinomas may come from either the pancreatic cells themselves or gastrin-expressing cells which have migrated from the duodenum. In the current study, we further characterized previously described transient pancreatic gastrin-expressing cells using cell lineage tracing in a pan-pancreatic progenitor and a pancreatic endocrine progenitor model. We provide evidence showing that pancreatic gastrin-expressing cells, found from embryonic day 12.5 until postnatal day 7, are derived from pancreatic Ptf1a(+) and neurogenin 3-expressing (Ngn3(+)) progenitors. Importantly, the majority of them coexpress glucagon, with 4% coexpressing insulin, indicating that they are a temporary subpopulation of both alpha and beta cells. Interestingly, Men1 disruption in both Ngn3 progenitors and beta and alpha cells resulted in the development of pancreatic gastrin-expressing tumors, suggesting that the latter developed from islet cells. Finally, we detected gastrin expression using three human cohorts with pancreatic endocrine tumors (pNETs) that have not been diagnosed as gastrinomas (in 9/34 pNETs from 6/14 patients with multiple endocrine neoplasia type 1, in 5/35 sporadic nonfunctioning pNETs, and in 2/20 sporadic insulinomas), consistent with observations made in mouse models. Our work provides insight into the histogenesis of pancreatic gastrin-expressing tumors. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  18. Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

    Energy Technology Data Exchange (ETDEWEB)

    Perl, S; Kushner, J A; Buchholz, B A; Meeker, A K; Stein, G M; Hsieh, M; Kirby, M; Pechhold, S; Liu, E H; Harlan, D M; Tisdale, J F

    2010-03-15

    Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 ({sup 14}C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). {sup 14}C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA {sup 14}C content relative to a well-established {sup 14}C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with the BrdU/IdU turnover data, beta-cell DNA {sup 14}C content indicated the cells 'birth date' occurred within the subject's first 30 years of life. Under typical circumstances, adult human beta-cells and their cellular precursors are established by young adulthood.

  19. ATP release, generation and hydrolysis in exocrine pancreatic duct cells

    DEFF Research Database (Denmark)

    Kowal, Justyna Magdalena; Yegutkin, G.G.; Novak, Ivana

    2015-01-01

    Extracellular adenosine triphosphate (ATP) regulates pancreatic duct function via P2Y and P2X receptors. It is well known that ATP is released from upstream pancreatic acinar cells. The ATP homeostasis in pancreatic ducts, which secrete bicarbonate-rich fluid, has not yet been examined. First, ou...... may be important in pancreas physiology and potentially in pancreas pathophysiology....... aim was to reveal whether pancreatic duct cells release ATP locally and whether they enzymatically modify extracellular nucleotides/sides. Second, we wished to explore which physiological and pathophysiological factors may be important in these processes. Using a human pancreatic duct cell line, Capan...

  20. Pancreatic beta cell function increases in a linear dose-response manner following exercise training in adults with prediabetes

    DEFF Research Database (Denmark)

    Malin, Steven K; Solomon, Thomas; Blaszczak, Alecia

    2013-01-01

    While some studies suggest that a linear dose-response relationship exists between exercise and insulin sensitivity, the exercise dose required to enhance pancreatic beta-cell function is unknown. Thirty-five older, obese adults with prediabetes underwent a progressive 12-week supervised exercise...

  1. Glucocorticoids Inhibit Basal and Hormone-Induced Serotonin Synthesis in Pancreatic Beta Cells.

    Directory of Open Access Journals (Sweden)

    Moina Hasni Ebou

    Full Text Available Diabetes is a major complication of chronic Glucocorticoids (GCs treatment. GCs induce insulin resistance and also inhibit insulin secretion from pancreatic beta cells. Yet, a full understanding of this negative regulation remains to be deciphered. In the present study, we investigated whether GCs could inhibit serotonin synthesis in beta cell since this neurotransmitter has been shown to be involved in the regulation of insulin secretion. To this aim, serotonin synthesis was evaluated in vitro after treatment with GCs of either islets from CD1 mice or MIN6 cells, a beta-cell line. We also explored the effect of GCs on the stimulation of serotonin synthesis by several hormones such as prolactin and GLP 1. We finally studied this regulation in islet in two in vivo models: mice treated with GCs and with liraglutide, a GLP1 analog, and mice deleted for the glucocorticoid receptor in the pancreas. We showed in isolated islets and MIN6 cells that GCs decreased expression and activity of the two key enzymes of serotonin synthesis, Tryptophan Hydroxylase 1 (Tph1 and 2 (Tph2, leading to reduced serotonin contents. GCs also blocked the induction of serotonin synthesis by prolactin or by a previously unknown serotonin activator, the GLP-1 analog exendin-4. In vivo, activation of the Glucagon-like-Peptide-1 receptor with liraglutide during 4 weeks increased islet serotonin contents and GCs treatment prevented this increase. Finally, islets from mice deleted for the GR in the pancreas displayed an increased expression of Tph1 and Tph2 and a strong increased serotonin content per islet. In conclusion, our results demonstrate an original inhibition of serotonin synthesis by GCs, both in basal condition and after stimulation by prolactin or activators of the GLP-1 receptor. This regulation may contribute to the deleterious effects of GCs on beta cells.

  2. Early peroxisome proliferator-activated receptor gamma regulated genes involved in expansion of pancreatic beta cell mass

    Directory of Open Access Journals (Sweden)

    Vivas Yurena

    2011-12-01

    Full Text Available Abstract Background The progression towards type 2 diabetes depends on the allostatic response of pancreatic beta cells to synthesise and secrete enough insulin to compensate for insulin resistance. The endocrine pancreas is a plastic tissue able to expand or regress in response to the requirements imposed by physiological and pathophysiological states associated to insulin resistance such as pregnancy, obesity or ageing, but the mechanisms mediating beta cell mass expansion in these scenarios are not well defined. We have recently shown that ob/ob mice with genetic ablation of PPARγ2, a mouse model known as the POKO mouse failed to expand its beta cell mass. This phenotype contrasted with the appropriate expansion of the beta cell mass observed in their obese littermate ob/ob mice. Thus, comparison of these models islets particularly at early ages could provide some new insights on early PPARγ dependent transcriptional responses involved in the process of beta cell mass expansion Results Here we have investigated PPARγ dependent transcriptional responses occurring during the early stages of beta cell adaptation to insulin resistance in wild type, ob/ob, PPARγ2 KO and POKO mice. We have identified genes known to regulate both the rate of proliferation and the survival signals of beta cells. Moreover we have also identified new pathways induced in ob/ob islets that remained unchanged in POKO islets, suggesting an important role for PPARγ in maintenance/activation of mechanisms essential for the continued function of the beta cell. Conclusions Our data suggest that the expansion of beta cell mass observed in ob/ob islets is associated with the activation of an immune response that fails to occur in POKO islets. We have also indentified other PPARγ dependent differentially regulated pathways including cholesterol biosynthesis, apoptosis through TGF-β signaling and decreased oxidative phosphorylation.

  3. Effects of methyl mercury exposure on pancreatic beta cell development and function.

    Science.gov (United States)

    Schumacher, Lauren; Abbott, Louise C

    2017-01-01

    Methyl mercury is an environmental contaminant of worldwide concern. Since the discovery of methyl mercury exposure due to eating contaminated fish as the underlying cause of the Minamata disaster, the scientific community has known about the sensitivity of the developing central nervous system to mercury toxicity. Warnings are given to pregnant women and young children to limit consumption of foods containing methyl mercury to protect the embryonic, fetal and postnatally developing central nervous system. However, evidence also suggests that exposure to methyl mercury or various forms of inorganic mercury may also affect development and function of other organs. Numerous reports indicate a worldwide increase in diabetes, particularly type 2 diabetes. Quite recently, methyl mercury has been shown to have adverse effects on pancreatic beta (β) cell development and function, resulting in insulin resistance and hyperglycemia and may even lead to the development of diabetes. This review discusses possible mechanisms by which methyl mercury exposure may adversely affect pancreatic β cell development and function, and the role that methyl mercury exposure may have in the reported worldwide increase in diabetes, particularly type 2 diabetes. While additional information is needed regarding associations between mercury exposure and specific mechanisms of the pathogenesis of diabetes in the human population, methyl mercury's adverse effects on the body's natural sources of antioxidants suggest that one possible therapeutic strategy could involve supplementation with antioxidants. Thus, it is important that additional investigation be undertaken into the role of methyl mercury exposure and reduced pancreatic β cell function. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Calcium Co-regulates Oxidative Metabolism and ATP Synthase-dependent Respiration in Pancreatic Beta Cells

    Science.gov (United States)

    De Marchi, Umberto; Thevenet, Jonathan; Hermant, Aurelie; Dioum, Elhadji; Wiederkehr, Andreas

    2014-01-01

    Mitochondrial energy metabolism is essential for glucose-induced calcium signaling and, therefore, insulin granule exocytosis in pancreatic beta cells. Calcium signals are sensed by mitochondria acting in concert with mitochondrial substrates for the full activation of the organelle. Here we have studied glucose-induced calcium signaling and energy metabolism in INS-1E insulinoma cells and human islet beta cells. In insulin secreting cells a surprisingly large fraction of total respiration under resting conditions is ATP synthase-independent. We observe that ATP synthase-dependent respiration is markedly increased after glucose stimulation. Glucose also causes a very rapid elevation of oxidative metabolism as was followed by NAD(P)H autofluorescence. However, neither the rate of the glucose-induced increase nor the new steady-state NAD(P)H levels are significantly affected by calcium. Our findings challenge the current view, which has focused mainly on calcium-sensitive dehydrogenases as the target for the activation of mitochondrial energy metabolism. We propose a model of tight calcium-dependent regulation of oxidative metabolism and ATP synthase-dependent respiration in beta cell mitochondria. Coordinated activation of matrix dehydrogenases and respiratory chain activity by calcium allows the respiratory rate to change severalfold with only small or no alterations of the NAD(P)H/NAD(P)+ ratio. PMID:24554722

  5. Intermittent fasting preserves beta-cell mass in obesity-induced diabetes via the autophagy-lysosome pathway.

    Science.gov (United States)

    Liu, Haiyan; Javaheri, Ali; Godar, Rebecca J; Murphy, John; Ma, Xiucui; Rohatgi, Nidhi; Mahadevan, Jana; Hyrc, Krzysztof; Saftig, Paul; Marshall, Connie; McDaniel, Michael L; Remedi, Maria S; Razani, Babak; Urano, Fumihiko; Diwan, Abhinav

    2017-01-01

    Obesity-induced diabetes is characterized by hyperglycemia, insulin resistance, and progressive beta cell failure. In islets of mice with obesity-induced diabetes, we observe increased beta cell death and impaired autophagic flux. We hypothesized that intermittent fasting, a clinically sustainable therapeutic strategy, stimulates autophagic flux to ameliorate obesity-induced diabetes. Our data show that despite continued high-fat intake, intermittent fasting restores autophagic flux in islets and improves glucose tolerance by enhancing glucose-stimulated insulin secretion, beta cell survival, and nuclear expression of NEUROG3, a marker of pancreatic regeneration. In contrast, intermittent fasting does not rescue beta-cell death or induce NEUROG3 expression in obese mice with lysosomal dysfunction secondary to deficiency of the lysosomal membrane protein, LAMP2 or haplo-insufficiency of BECN1/Beclin 1, a protein critical for autophagosome formation. Moreover, intermittent fasting is sufficient to provoke beta cell death in nonobese lamp2 null mice, attesting to a critical role for lysosome function in beta cell homeostasis under fasting conditions. Beta cells in intermittently-fasted LAMP2- or BECN1-deficient mice exhibit markers of autophagic failure with accumulation of damaged mitochondria and upregulation of oxidative stress. Thus, intermittent fasting preserves organelle quality via the autophagy-lysosome pathway to enhance beta cell survival and stimulates markers of regeneration in obesity-induced diabetes.

  6. Glucagon-like peptide-1 counteracts the detrimental effects of Advanced Glycation End-Products in the pancreatic beta cell line HIT-T 15

    International Nuclear Information System (INIS)

    Puddu, A.; Storace, D.; Durante, A.; Odetti, P.; Viviani, G.L.

    2010-01-01

    Research highlights: → GLP-1 prevents AGEs-induced cell death. → GLP-1 prevents AGEs-induced oxidative stress. → GLP-1 ameliorated AGEs-induced cell dysfunction. → GLP-1 attenuates AGEs-induced RAGE increment. → GLP-1 counteracts AGEs-induced pancreatic cell death and dysfunction. -- Abstract: Advanced Glycation End-Products (AGEs), a group of compounds resulting from the non-enzymatic reaction of reducing sugars with the free amino group of proteins, are implicated in diabetic complications. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T 15 to high concentrations of AGEs significantly decreases cell proliferation and insulin secretion, and affects transcription factors regulating insulin gene transcription. The glucagon-like peptide-1 (GLP-1) is an incretin hormone that increases proinsulin biosynthesis, stimulates insulin secretion, and improves pancreatic beta-cell viability. The aim of this work was to investigate the effects of GLP-1 on the function and viability of HIT-T 15 cells cultured with AGEs. HIT-T 15 cells were cultured for 5 days in presence of AGEs alone, or supplemented with 10 nmol/l GLP-1. Cell viability, insulin secretion, redox balance, and expression of the AGEs receptor (RAGE) were then determined. The results showed that GLP-1 protected beta cell against AGEs-induced cell death preventing both apoptosis and necrosis. Moreover, addition of GLP-1 to the AGEs culture medium restored the redox balance, improved the responsiveness to glucose, and attenuated AGEs-induced RAGE expression. These findings provide evidence that GLP-1 protects beta cells from the dangerous effects of AGEs.

  7. What are the potential benefits of clinical beta-cell imaging in diabetes mellitus?

    Science.gov (United States)

    Göke, Burkhard

    2010-05-01

    Previously, studies of the endocrine pancreatic beta-cell were mainly performed ex vivo by morphological means. This data supported the analysis of pathophysiological changes in the pancreatic islet during insults such as diabetes mellitus. Metabolic testing of the pancreatic islet by assaying hormone parameters such als plasma insulin or C-peptide combined with more or less sophisticated calculations allowed conclusions about states of insulin resistance or secretory failure. It also allowed certain correlations of endocrine function with beta-cell mass. Today, with firmer pathophysiological concepts about beta-cell failure, modern protocols of islet transplantation, and drugs on the market coming with promises of preservation or even expansion of beta-cell mass in diabetes mellitus it has become very attractive to search for tools measuring beta-cell mass, if possible even repeatingly in the same organism in vivo. From a clinical point of view, the potential of pancreatic beta-cell mass imaging technologies is looked upon with high expectations. Methodologically, the decisive question is whether it is likely that future beta-cell imaging will provide significant advantages over the metabolic methods already in hand. With new in vivo tools, studies of beta-cell mass and function may offer even new approaches stratifying patients to anti-diabetic therapies.

  8. Rising Intracellular Zinc by Membrane Depolarization and Glucose in Insulin-Secreting Clonal HIT-T15 Beta Cells

    Directory of Open Access Journals (Sweden)

    Kira G. Slepchenko

    2012-01-01

    Full Text Available Zinc (Zn2+ appears to be intimately involved in insulin metabolism since insulin secretion is correlated with zinc secretion in response to glucose stimulation, but little is known about the regulation of zinc homeostasis in pancreatic beta-cells. This study set out to identify the intracellular zinc transient by imaging free cytosolic zinc in HIT-T15 beta-cells with fluorescent zinc indicators. We observed that membrane depolarization by KCl (30–60 mM was able to induce a rapid increase in cytosolic concentration of zinc. Multiple zinc transients of similar magnitude were elicited during repeated stimulations. The amplitude of zinc responses was not affected by the removal of extracellular calcium or zinc. However, the half-time of the rising slope was significantly slower after removing extracellular zinc with zinc chelator CaEDTA, suggesting that extracellular zinc affect the initial rising phase of zinc response. Glucose (10 mM induced substantial and progressive increases in intracellular zinc concentration in a similar way as KCl, with variation in the onset and the duration of zinc mobilization. It is known that the depolarization of beta-cell membrane is coupled with the secretion of insulin. Rising intracellular zinc concentration may act as a critical signaling factor in insulin metabolism of pancreatic beta-cells.

  9. Role of transcription factor KLF11 and its diabetes-associated gene variants in pancreatic beta cell function

    Science.gov (United States)

    Neve, Bernadette; Fernandez-Zapico, Martin E.; Ashkenazi-Katalan, Vered; Dina, Christian; Hamid, Yasmin H.; Joly, Erik; Vaillant, Emmanuel; Benmezroua, Yamina; Durand, Emmanuelle; Bakaher, Nicolas; Delannoy, Valerie; Vaxillaire, Martine; Cook, Tiffany; Dallinga-Thie, Geesje M.; Jansen, Hans; Charles, Marie-Aline; Clément, Karine; Galan, Pilar; Hercberg, Serge; Helbecque, Nicole; Charpentier, Guillaume; Prentki, Marc; Hansen, Torben; Pedersen, Oluf; Urrutia, Raul; Melloul, Danielle; Froguel, Philippe

    2005-01-01

    KLF11 (TIEG2) is a pancreas-enriched transcription factor that has elicited significant attention because of its role as negative regulator of exocrine cell growth in vitro and in vivo. However, its functional role in the endocrine pancreas remains to be established. Here, we report, for the first time, to our knowledge, the characterization of KLF11 as a glucose-inducible regulator of the insulin gene. A combination of random oligonucleotide binding, EMSA, luciferase reporter, and chromatin immunoprecipitation assays shows that KLF11 binds to the insulin promoter and regulates its activity in beta cells. Genetic analysis of the KLF11 gene revealed two rare variants (Ala347Ser and Thr220Met) that segregate with diabetes in families with early-onset type 2 diabetes, and significantly impair its transcriptional activity. In addition, analysis of 1,696 type 2 diabetes mellitus and 1,776 normoglycemic subjects show a frequent polymorphic Gln62Arg variant that significantly associates with type 2 diabetes mellitus in North European populations (OR = 1.29, P = 0.00033). Moreover, this variant alters the corepressor mSin3A-binding activity of KLF11, impairs the activation of the insulin promoter and shows lower levels of insulin expression in pancreatic beta cells. In addition, subjects carrying the Gln62Arg allele show decreased plasma insulin after an oral glucose challenge. Interestingly, all three nonsynonymous KLF11 variants show increased repression of the catalase 1 promoter, suggesting a role in free radical clearance that may render beta cells more sensitive to oxidative stress. Thus, both functional and genetic analyses reveal that KLF11 plays a role in the regulation of pancreatic beta cell physiology, and its variants may contribute to the development of diabetes. PMID:15774581

  10. Cocoa Phenolic Extract Protects Pancreatic Beta Cells against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Laura Bravo

    2013-07-01

    Full Text Available Diabetes mellitus is associated with reductions in glutathione, supporting the critical role of oxidative stress in its pathogenesis. Antioxidant food components such as flavonoids have a protective role against oxidative stress-induced degenerative and age-related diseases. Flavonoids constitute an important part of the human diet; they can be found in most plant foods, including green tea, grapes or cocoa and possess multiple biological activities. This study investigates the chemo-protective effect of a cocoa phenolic extract (CPE containing mainly flavonoids against oxidative stress induced by tert-butylhydroperoxide (t-BOOH on Ins-1E pancreatic beta cells. Cell viability and oxidative status were evaluated. Ins-1E cells treatment with 5–20 μg/mL CPE for 20 h evoked no cell damage and did not alter ROS production. Addition of 50 μM t-BOOH for 2 h increased ROS and carbonyl groups content and decreased reduced glutathione level. Pre-treatment of cells with CPE significantly prevented the t-BOOH-induced ROS and carbonyl groups and returned antioxidant defences to adequate levels. Thus, Ins-1E cells treated with CPE showed a remarkable recovery of cell viability damaged by t-BOOH, indicating that integrity of surviving machineries in the CPE-treated cells was notably protected against the oxidative insult.

  11. Stevioside improves pancreatic beta-cell function during glucotoxicity via regulation of acetyl-CoA carboxylase.

    Science.gov (United States)

    Chen, Jianguo; Jeppesen, Per Bendix; Nordentoft, Iver; Hermansen, Kjeld

    2007-06-01

    Chronic hyperglycemia is detrimental to pancreatic beta-cells, causing impaired insulin secretion and beta-cell turnover. The characteristic secretory defects are increased basal insulin secretion (BIS) and a selective loss of glucose-stimulated insulin secretion (GSIS). Several recent studies support the view that the acetyl-CoA carboxylase (ACC) plays a pivotal role for GSIS. We have shown that stevioside (SVS) enhances insulin secretion and ACC gene expression. Whether glucotoxicity influences ACC and whether this action can be counteracted by SVS are not known. To investigate this, we exposed isolated mouse islets as well as clonal INS-1E beta-cells for 48 h to 27 or 16.7 mM glucose, respectively. We found that 48-h exposure to high glucose impairs GSIS from mouse islets and INS-1E cells, an effect that is partly counteracted by SVS. The ACC dephosphorylation inhibitor okadaic acid (OKA, 10(-8) M), and 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR, 10(-4) M), an activator of 5'-AMP protein kinase that phosphorylates ACC, eliminated the beneficial effect of SVS. 5-Tetrade-cyloxy-2-furancarboxylic acid (TOFA), the specific ACC inhibitor, blocked the effect of SVS as well. During glucotoxity, ACC gene expression, ACC protein, and phosphorylated ACC protein were increased in INS-1E beta-cells. SVS pretreatment further increased ACC gene expression with strikingly elevated ACC activity and increased glucose uptake accompanied by enhanced GSIS. Our studies show that glucose is a potent stimulator of ACC and that SVS to some extent counteracts glucotoxicity via increased ACC activity. SVS possesses the potential to alleviate negative effects of glucotoxicity in beta-cells via a unique mechanism of action.

  12. Bone morphogenetic proteins in inflammation, glucose homeostasis and adipose tissue energy metabolism

    DEFF Research Database (Denmark)

    Grgurevic, Lovorka; Christensen, Gitte Lund; Schulz, Tim J

    2016-01-01

    implicated in pancreas development as well as control of adult glucose homeostasis. Lastly, we review the recently recognized role of BMPs in brown adipose tissue formation and their consequences for energy expenditure and adiposity. In summary, BMPs play a pivotal role in metabolism beyond their role...... homeostasis (anaemia, hemochromatosis) and oxidative damage. The second and third parts of this review focus on BMPs in the development of metabolic pathologies such as type-2 diabetes mellitus and obesity. The pancreatic beta cells are the sole source of the hormone insulin and BMPs have recently been...

  13. PED/PEA-15 inhibits hydrogen peroxide-induced apoptosis in Ins-1E pancreatic beta-cells via PLD-1.

    Directory of Open Access Journals (Sweden)

    Francesca Fiory

    Full Text Available The small scaffold protein PED/PEA-15 is involved in several different physiologic and pathologic processes, such as cell proliferation and survival, diabetes and cancer. PED/PEA-15 exerts an anti-apoptotic function due to its ability to interfere with both extrinsic and intrinsic apoptotic pathways in different cell types. Recent evidence shows that mice overexpressing PED/PEA-15 present larger pancreatic islets and increased beta-cells mass. In the present work we investigated PED/PEA-15 role in hydrogen peroxide-induced apoptosis in Ins-1E beta-cells. In pancreatic islets isolated from Tg(PED/PEA-15 mice hydrogen peroxide-induced DNA fragmentation was lower compared to WT islets. TUNEL analysis showed that PED/PEA-15 overexpression increases the viability of Ins-1E beta-cells and enhances their resistance to apoptosis induced by hydrogen peroxide exposure. The activity of caspase-3 and the cleavage of PARP-1 were markedly reduced in Ins-1E cells overexpressing PED/PEA-15 (Ins-1E(PED/PEA-15. In parallel, we observed a decrease of the mRNA levels of pro-apoptotic genes Bcl-xS and Bad. In contrast, the expression of the anti-apoptotic gene Bcl-xL was enhanced. Accordingly, DNA fragmentation was higher in control cells compared to Ins-1E(PED/PEA-15 cells. Interestingly, the preincubation with propranolol, an inhibitor of the pathway of PLD-1, a known interactor of PED/PEA-15, responsible for its deleterious effects on glucose tolerance, abolishes the antiapoptotic effects of PED/PEA-15 overexpression in Ins-1E beta-cells. The same results have been obtained by inhibiting PED/PEA-15 interaction with PLD-1 in Ins-1E(PED/PEA-15. These results show that PED/PEA-15 overexpression is sufficient to block hydrogen peroxide-induced apoptosis in Ins-1E cells through a PLD-1 mediated mechanism.

  14. Characterization of the distal promoter of the human pyruvate carboxylase gene in pancreatic beta cells.

    Directory of Open Access Journals (Sweden)

    Ansaya Thonpho

    Full Text Available Pyruvate carboxylase (PC is an enzyme that plays a crucial role in many biosynthetic pathways in various tissues including glucose-stimulated insulin secretion. In the present study, we identify promoter usage of the human PC gene in pancreatic beta cells. The data show that in the human, two alternative promoters, proximal and distal, are responsible for the production of multiple mRNA isoforms as in the rat and mouse. RT-PCR analysis performed with cDNA prepared from human liver and islets showed that the distal promoter, but not the proximal promoter, of the human PC gene is active in pancreatic beta cells. A 1108 bp fragment of the human PC distal promoter was cloned and analyzed. It contains no TATA box but possesses two CCAAT boxes, and other putative transcription factor binding sites, similar to those of the distal promoter of rat PC gene. To localize the positive regulatory region in the human PC distal promoter, 5'-truncated and the 25-bp and 15-bp internal deletion mutants of the human PC distal promoter were generated and used in transient transfections in INS-1 832/13 insulinoma and HEK293T (kidney cell lines. The results indicated that positions -340 to -315 of the human PC distal promoter serve as (an activator element(s for cell-specific transcription factor, while the CCAAT box at -71/-67, a binding site for nuclear factor Y (NF-Y, as well as a GC box at -54/-39 of the human PC distal promoter act as activator sequences for basal transcription.

  15. Are genetic variants in the platelet-derived growth factor [beta] gene associated with chronic pancreatitis?

    Science.gov (United States)

    Muddana, Venkata; Park, James; Lamb, Janette; Yadav, Dhiraj; Papachristou, Georgios I; Hawes, Robert H; Brand, Randall; Slivka, Adam; Whitcomb, David C

    2010-11-01

    Platelet-derived growth factor [beta] (PDGF-[beta]) is a major signal in proliferation and matrix synthesis through activated pancreatic stellate cells, leading to fibrosis of the pancreas. Recurrent acute pancreatitis (RAP) seems to predispose to chronic pancreatitis (CP) in some patients but not others. We tested the hypothesis that 2 known PDGF-[beta] polymorphisms are associated with progression from RAP to CP. We also tested the hypothesis that PDGF-[beta] polymorphisms in combination with environmental risk factors such as alcohol and smoking are associated with CP. Three hundred eighty-two patients with CP (n = 176) and RAP (n = 206) and 251 controls were evaluated. Platelet-derived growth factor [beta] polymorphisms +286 A/G (rs#1800818) seen in 5'-UTR and +1135 A/C (rs#1800817) in first intron were genotyped using single-nucleotide polymorphism polymerase chain reaction approach and confirmed by DNA sequencing. The genotypic frequencies for PDGF-[beta] polymorphisms in positions +286 and +1135 were found to be similar in controls and patients with RAP and CP. There was no difference in genotypic frequencies among RAP, CP, and controls in subjects in the alcohol and smoking subgroups. Known variations in the PDGF-[beta] gene do not have a significant effect on promoting or preventing fibrogenesis in pancreatitis. Further evaluation of this important pathway is warranted.

  16. Activation of PPAR{delta} up-regulates fatty acid oxidation and energy uncoupling genes of mitochondria and reduces palmitate-induced apoptosis in pancreatic {beta}-cells

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Jun; Jiang, Li; Lue, Qingguo; Ke, Linqiu [Department of Endocrinology, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu, Sichuan 610041 (China); Li, Xiaoyu [State Key Laboratory of Oral Diseases, Sichuan University, No. 14, 3rd Section, Renmin South Road, Chengdu, Sichuan 610041 (China); Tong, Nanwei, E-mail: buddyjun@hotmail.com [Department of Endocrinology, West China Hospital of Sichuan University, 37 Guoxue Lane, Chengdu, Sichuan 610041 (China)

    2010-01-15

    Recent evidence indicates that decreased oxidative capacity, lipotoxicity, and mitochondrial aberrations contribute to the development of insulin resistance and type 2 diabetes. The goal of this study was to investigate the effects of peroxisome proliferator-activated receptor {delta} (PPAR{delta}) activation on lipid oxidation, mitochondrial function, and insulin secretion in pancreatic {beta}-cells. After HIT-T15 cells (a {beta}-cell line) were exposed to high concentrations of palmitate and GW501516 (GW; a selective agonist of PPAR{delta}), we found that administration of GW increased the expression of PPAR{delta} mRNA. GW-induced activation of PPAR{delta} up-regulated carnitine palmitoyltransferase 1 (CPT1), long-chain acyl-CoA dehydrogenase (LCAD), pyruvate dehydrogenase kinase 4 (PDK4), and uncoupling protein 2 (UCP2); alleviated mitochondrial swelling; attenuated apoptosis; and reduced basal insulin secretion induced by increased palmitate in HIT cells. These results suggest that activation of PPAR{delta} plays an important role in protecting pancreatic {beta}-cells against aberrations caused by lipotoxicity in metabolic syndrome and diabetes.

  17. Enrichment of putative pancreatic progenitor cells from mice by sorting for prominin1 (CD133) and platelet-derived growth factor receptor beta.

    Science.gov (United States)

    Hori, Yuichi; Fukumoto, Miki; Kuroda, Yoshikazu

    2008-11-01

    Success in islet transplantation-based therapies for type 1 diabetes mellitus and an extreme shortage of pancreatic islets have motivated recent efforts to develop renewable sources of islet-replacement tissue. Although pancreatic progenitor cells hold a promising potential, only a few attempts have been made at the prospective isolation of pancreatic stem/progenitor cells, because of the lack of specific markers and the development of effective cell culture methods. We found that prominin1 (also known as CD133) recognized the undifferentiated epithelial cells, whereas platelet-derived growth factor receptor beta (PDGFRbeta) was expressed on the mesenchymal cells in the mouse embryonic pancreas. We then developed an isolation method for putative stem/progenitor cells by flow cytometric cell sorting and characterized their potential for differentiation to pancreatic tissue using both in vitro and in vivo protocols. Flow cytometry and the subsequent reverse transcription-polymerase chain reaction and microarray analysis revealed pancreatic epithelial progenitor cells to be highly enriched in the prominin1(high)PDGFRbeta(-) cell population. During in vivo differentiation, these cell populations were able to differentiate into endocrine, exocrine, and ductal tissues, including the formation of an insulin-producing cell cluster. We established the prospective isolation of putative pancreatic epithelial progenitor cells by sorting for prominin1 and PDGFRbeta. Since this strategy is based on the cell surface markers common to human and rodents, these findings may lead to the development of new strategies to derive transplantable islet-replacement tissues from human pancreatic stem/progenitor cells. Disclosure of potential conflicts of interest is found at the end of this article.

  18. Production of pancreatic hormone-expressing endocrine cells from human embryonic stem cells.

    Science.gov (United States)

    D'Amour, Kevin A; Bang, Anne G; Eliazer, Susan; Kelly, Olivia G; Agulnick, Alan D; Smart, Nora G; Moorman, Mark A; Kroon, Evert; Carpenter, Melissa K; Baetge, Emmanuel E

    2006-11-01

    Of paramount importance for the development of cell therapies to treat diabetes is the production of sufficient numbers of pancreatic endocrine cells that function similarly to primary islets. We have developed a differentiation process that converts human embryonic stem (hES) cells to endocrine cells capable of synthesizing the pancreatic hormones insulin, glucagon, somatostatin, pancreatic polypeptide and ghrelin. This process mimics in vivo pancreatic organogenesis by directing cells through stages resembling definitive endoderm, gut-tube endoderm, pancreatic endoderm and endocrine precursor--en route to cells that express endocrine hormones. The hES cell-derived insulin-expressing cells have an insulin content approaching that of adult islets. Similar to fetal beta-cells, they release C-peptide in response to multiple secretory stimuli, but only minimally to glucose. Production of these hES cell-derived endocrine cells may represent a critical step in the development of a renewable source of cells for diabetes cell therapy.

  19. Progenitor potential of nkx6.1-expressing cells throughout zebrafish life and during beta cell regeneration.

    Science.gov (United States)

    Ghaye, Aurélie P; Bergemann, David; Tarifeño-Saldivia, Estefania; Flasse, Lydie C; Von Berg, Virginie; Peers, Bernard; Voz, Marianne L; Manfroid, Isabelle

    2015-09-02

    In contrast to mammals, the zebrafish has the remarkable capacity to regenerate its pancreatic beta cells very efficiently. Understanding the mechanisms of regeneration in the zebrafish and the differences with mammals will be fundamental to discovering molecules able to stimulate the regeneration process in mammals. To identify the pancreatic cells able to give rise to new beta cells in the zebrafish, we generated new transgenic lines allowing the tracing of multipotent pancreatic progenitors and endocrine precursors. Using novel bacterial artificial chromosome transgenic nkx6.1 and ascl1b reporter lines, we established that nkx6.1-positive cells give rise to all the pancreatic cell types and ascl1b-positive cells give rise to all the endocrine cell types in the zebrafish embryo. These two genes are initially co-expressed in the pancreatic primordium and their domains segregate, not as a result of mutual repression, but through the opposite effects of Notch signaling, maintaining nkx6.1 expression while repressing ascl1b in progenitors. In the adult zebrafish, nkx6.1 expression persists exclusively in the ductal tree at the tip of which its expression coincides with Notch active signaling in centroacinar/terminal end duct cells. Tracing these cells reveals that they are able to differentiate into other ductal cells and into insulin-expressing cells in normal (non-diabetic) animals. This capacity of ductal cells to generate endocrine cells is supported by the detection of ascl1b in the nkx6.1:GFP ductal cell transcriptome. This transcriptome also reveals, besides actors of the Notch and Wnt pathways, several novel markers such as id2a. Finally, we show that beta cell ablation in the adult zebrafish triggers proliferation of ductal cells and their differentiation into insulin-expressing cells. We have shown that, in the zebrafish embryo, nkx6.1+ cells are bona fide multipotent pancreatic progenitors, while ascl1b+ cells represent committed endocrine precursors. In

  20. Mechanisms of pancreatic beta-cell growth and regeneration

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis

    1989-01-01

    Information about the mechanism of beta-cell growth and regeneration may be obtained by studies of insulinoma cells. In the present study the growth and function of the rat insulinoma cell lines RINm5F and 5AH were evaluated by addition of serum, hormones, and growth factors. It was found...... of insulin mRNA content showed that the insulinoma cells only contained about 2% of that of normal rat beta-cells. These results are discussed in relation to the role of growth factors, oncogenes, and differentiation in the growth and regeneration of beta-cells....... that transferrin is the only obligatory factor whereas growth hormone, epidermal growth factor, fibroblast growth factor, and TRH had modulating effects. A heat-labile heparin binding serum factor which stimulated thymidine incorporation but not cell proliferation was demonstrated in human serum. Measurements...

  1. Insulin-like Growth Factor 1 Regulates the Expression of ATP-Binding Cassette Transporter A1 in Pancreatic Beta Cells.

    Science.gov (United States)

    Lyu, J; Imachi, H; Iwama, H; Zhang, H; Murao, K

    2016-05-01

    ATP-binding cassette transporter A1 (ABCA1) in pancreatic beta cells influences insulin secretion and cholesterol homeostasis. The present study investigates whether insulin-like growth factor 1 (IGF-1), which mediates stimulation of ABCA1 gene expression, could also interfere with the phosphatidylinositol 3-kinase (PI3-K) cascade.ABCA1 expression was examined by real-time polymerase chain reaction (PCR), Western blot analysis, and a reporter gene assay in rat insulin-secreting INS-1 cells incubated with IGF-1. The binding of forkhead box O1 (FoxO1) protein to the ABCA1 promoter was assessed by a chromatin immunoprecipitation (ChIP) assay. ABCA1 protein levels increased in response to rising concentrations of IGF-1. Real-time PCR analysis showed a significant increase in ABCA1 mRNA expression. However, both effects were suppressed after silencing the IGF-1 receptor. In parallel with its effect on endogenous ABCA1 mRNA levels, IGF-1 induced the activity of a reporter construct containing the ABCA1 promoter, while it was abrogated by LY294002, a specific inhibitor of PI3-K. Constitutively active Akt stimulated activity of the ABCA1 promoter, and a dominant-negative mutant of Akt or mutagenesis of the FoxO1 response element in the ABCA1 promoter abolished the ability of IGF-1 to stimulate promoter activity. A ChIP assay showed that FoxO1 mediated its transcriptional activity by directly binding to the ABCA1 promoter region. The knockdown of FoxO1 disrupted the effect of IGF-1 on ABCA1 expression. Furthermore, IGF-1 promoted cholesterol efflux and reduced the pancreatic lipotoxicity. These results demonstrate that the PI3-K/Akt/FoxO1 pathway contributes to the regulation of ABCA1 expression in response to IGF-1 stimulation. © Georg Thieme Verlag KG Stuttgart · New York.

  2. Positron emission tomography study on pancreatic somatostatin receptors in normal and diabetic rats with {sup 68}Ga-DOTA-octreotide: A potential PET tracer for beta cell mass measurement

    Energy Technology Data Exchange (ETDEWEB)

    Sako, Takeo [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Division of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Hasegawa, Koki; Nishimura, Mie; Kanayama, Yousuke; Wada, Yasuhiro; Hayashinaka, Emi; Cui, Yilong; Kataoka, Yosky [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Senda, Michio [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Division of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Watanabe, Yasuyoshi, E-mail: yywata@riken.jp [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan)

    2013-12-06

    Highlights: •PET images showed high uptake of {sup 68}Ga-DOTA-octreotide in the normal pancreas. •{sup 68}Ga-DOTA-octreotide specifically binds to somatostatin receptors in the pancreas. •The pancreatic uptake of {sup 68}Ga-DOTA-octreotide was decreased in the diabetic rats. •{sup 68}Ga-DOTA-octreotide could be a candidate PET probe to measure the beta cell mass. -- Abstract: Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia, and the loss or dysfunction of pancreatic beta cells has been reported before the appearance of clinical symptoms and hyperglycemia. To evaluate beta cell mass (BCM) for improving the detection and treatment of DM at earlier stages, we focused on somatostatin receptors that are highly expressed in the pancreatic beta cells, and developed a positron emission tomography (PET) probe derived from octreotide, a metabolically stable somatostatin analog. Octreotide was conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), a chelating agent, and labeled with {sup 68}Gallium ({sup 68}Ga). After intravenous injection of {sup 68}Ga-DOTA-octreotide, a 90-min emission scan of the abdomen was performed in normal and DM model rats. The PET studies showed that {sup 68}Ga-DOTA-octreotide radioactivity was highly accumulated in the pancreas of normal rats and that the pancreatic accumulation was significantly reduced in the rats administered with an excess amount of unlabeled octreotide or after treatment with streptozotocin, which was used for the chemical induction of DM in rats. These results were in good agreement with the ex vivo biodistribution data. These results indicated that the pancreatic accumulation of {sup 68}Ga-DOTA-octreotide represented specific binding to the somatostatin receptors and reflected BCM. Therefore, PET imaging with {sup 68}Ga-DOTA-octreotide could be a potential tool for evaluating BCM.

  3. Pancreatic beta cells express two autoantigenic forms of glutamic acid decarboxylase, a 65-kDa hydrophilic form and a 64-kDa amphiphilic form which can be both membrane-bound and soluble

    DEFF Research Database (Denmark)

    Christgau, S; Schierbeck, H; Aanstoot, H J

    1991-01-01

    The 64-kDa pancreatic beta-cell autoantigen, which is a target of autoantibodies associated with early as well as progressive stages of beta-cell destruction, resulting in insulin-dependent diabetes (IDDM) in humans, has been identified as the gamma-aminobutyric acid-synthesizing enzyme glutamic...... acid decarboxylase. We have identified two autoantigenic forms of this protein in rat pancreatic beta-cells, a Mr 65,000 (GAD65) hydrophilic and soluble form of pI 6.9-7.1 and a Mr 64,000 (GAD64) component of pI 6.7. GAD64 is more abundant than GAD65 and has three distinct forms with regard to cellular...

  4. In Vivo Imaging of Transplanted Pancreatic Islets

    Directory of Open Access Journals (Sweden)

    Donghee Kim

    2018-01-01

    Full Text Available The beta-cells in the islets of Langerhans in the pancreas secrete insulin and play an important role in glucose homeostasis. Diabetes, characterized by hyperglycemia, results from an absolute or a relative deficiency of the pancreatic beta-cell mass. Islet transplantation has been considered to be a useful therapeutic approach, but it is largely unsuccessful because most of the transplanted islets are lost in the early stage of transplantation. To evaluate the efficacy of intervention methods for the improvement of islet survival, monitoring of the functional islet mass is needed. Various techniques to image and track transplanted islets have been investigated to assess islets after transplantation. In this review, recent progresses in imaging methods to visualize islets are discussed.

  5. The putative imidazoline receptor agonist, harmane, promotes intracellular calcium mobilisation in pancreatic beta-cells.

    Science.gov (United States)

    Squires, Paul E; Hills, Claire E; Rogers, Gareth J; Garland, Patrick; Farley, Sophia R; Morgan, Noel G

    2004-10-06

    beta-Carbolines (including harmane and pinoline) stimulate insulin secretion by a mechanism that may involve interaction with imidazoline I(3)-receptors but which also appears to be mediated by actions that are additional to imidazoline receptor agonism. Using the MIN6 beta-cell line, we now show that both the imidazoline I(3)-receptor agonist, efaroxan, and the beta-carboline, harmane, directly elevate cytosolic Ca(2+) and increase insulin secretion but that these responses display different characteristics. In the case of efaroxan, the increase in cytosolic Ca(2+) was readily reversible, whereas, with harmane, the effect persisted beyond removal of the agonist and resulted in the development of a repetitive train of Ca(2+)-oscillations whose frequency, but not amplitude, was concentration-dependent. Initiation of the Ca(2+)-oscillations by harmane was independent of extracellular calcium but was sensitive to both dantrolene and high levels (20 mM) of caffeine, suggesting the involvement of ryanodine receptor-gated Ca(2+)-release. The expression of ryanodine receptor-1 and ryanodine receptor-2 mRNA in MIN6 cells was confirmed using reverse transcription-polymerase chain reaction (RT-PCR) and, since low concentrations of caffeine (1 mM) or thimerosal (10 microM) stimulated increases in [Ca(2+)](i), we conclude that ryanodine receptors are functional in these cells. Furthermore, the increase in insulin secretion induced by harmane was attenuated by dantrolene, consistent with the involvement of ryanodine receptors in mediating this response. By contrast, the smaller insulin secretory response to efaroxan was unaffected by dantrolene. Harmane-evoked changes in cytosolic Ca(2+) were maintained by nifedipine-sensitive Ca(2+)-influx, suggesting the involvement of L-type voltage-gated Ca(2+)-channels. Taken together, these data imply that harmane may interact with ryanodine receptors to generate sustained Ca(2+)-oscillations in pancreatic beta-cells and that this effect

  6. Impact of Perturbed Pancreatic β-Cell Cholesterol Homeostasis on Adipose Tissue and Skeletal Muscle Metabolism

    Science.gov (United States)

    Cochran, Blake J.; Hou, Liming; Manavalan, Anil Paul Chirackal; Moore, Benjamin M.; Tabet, Fatiha; Sultana, Afroza; Cuesta Torres, Luisa; Tang, Shudi; Shrestha, Sudichhya; Senanayake, Praween; Patel, Mili; Ryder, William J.; Bongers, Andre; Maraninchi, Marie; Wasinger, Valerie C.; Westerterp, Marit; Tall, Alan R.; Barter, Philip J.

    2016-01-01

    Elevated pancreatic β-cell cholesterol levels impair insulin secretion and reduce plasma insulin levels. This study establishes that low plasma insulin levels have a detrimental effect on two major insulin target tissues: adipose tissue and skeletal muscle. Mice with increased β-cell cholesterol levels were generated by conditional deletion of the ATP-binding cassette transporters, ABCA1 and ABCG1, in β-cells (β-DKO mice). Insulin secretion was impaired in these mice under basal and high-glucose conditions, and glucose disposal was shifted from skeletal muscle to adipose tissue. The β-DKO mice also had increased body fat and adipose tissue macrophage content, elevated plasma interleukin-6 and MCP-1 levels, and decreased skeletal muscle mass. They were not, however, insulin resistant. The adipose tissue expansion and reduced skeletal muscle mass, but not the systemic inflammation or increased adipose tissue macrophage content, were reversed when plasma insulin levels were normalized by insulin supplementation. These studies identify a mechanism by which perturbation of β-cell cholesterol homeostasis and impaired insulin secretion increase adiposity, reduce skeletal muscle mass, and cause systemic inflammation. They further identify β-cell dysfunction as a potential therapeutic target in people at increased risk of developing type 2 diabetes. PMID:27702832

  7. Leucine metabolism in regulation of insulin secretion from pancreatic beta cells

    OpenAIRE

    Yang, Jichun; Chi, Yujing; Burkhardt, Brant R.; Guan, Youfei; Wolf, Bryan A

    2010-01-01

    Leucine, a the branched-chain amino acids that must be supplied in daily diet, plays an important role in controlling protein synthesis and regulating cell metabolism in various cell types. In pancreatic β cells, leucine acutely stimulates insulin secretion by serving as both metabolic fuel and allosteric activator of glutamate dehydrogenase to enhance glutaminolysis. Leucine has also been shown to regulate gene transcription and protein synthesis in pancreatic islet β cells via both mTOR-dep...

  8. Progress in molecular nuclear medicine imaging of pancreatic beta cells

    International Nuclear Information System (INIS)

    Wu Haifei; Yin Hongyan; Liu Shuai; Zhang Yifan

    2010-01-01

    Diabetes mellitus is a common and frequently occurring disease which seriously threaten the health of human beings. Type 1 and type 2 diabetes respectively results from being destroyed and insufficient beta-cell mass. The associated symptoms appear until 50%-60% decrease of beta-cell mass. Because pancreas is deeply located in the body, with few beta-cell mass, the current methods of clinical diagnosis are invasive and late. So diagnosis of metabolism disease of beta-cell early non-invasively becomes more and more popular, imaging diagnosis of diabetes mellitus becomes the focus of researches, but how to estimate the mass of beta-cell still an important subject in imaging technology. (authors)

  9. The islet beta-cell: fuel responsive and vulnerable.

    Science.gov (United States)

    Nolan, Christopher J; Prentki, Marc

    2008-10-01

    The pancreatic beta-cell senses blood nutrient levels and is modulated by neurohormonal signals so that it secretes insulin according to the need of the organism. Nutrient sensing involves marked metabolic activation, resulting in the production of coupling signals that promote insulin biosynthesis and secretion. The beta-cell's high capacity for nutrient sensing, however, necessitates reduced protection to nutrient toxicity. This potentially explains why in susceptible individuals, chronic fuel surfeit results in beta-cell failure and type 2 diabetes. Here we discuss recent insights into first, the biochemical basis of beta-cell signaling in response to glucose, amino acids and fatty acids, and second, beta-cell nutrient detoxification. We emphasize the emerging role of glycerolipid/fatty acid cycling in these processes.

  10. Fetal pancreatic beta-cell function in pregnancies complicated by maternal diabetes mellitus: relationship to fetal acidemia and macrosomia.

    Science.gov (United States)

    Salvesen, D R; Brudenell, J M; Proudler, A J; Crook, D; Nicolaides, K H

    1993-05-01

    Our purpose was to investigate the relationship between fetal pancreatic beta-cell function and fetal acidemia and macrosomia in pregnancies complicated by maternal diabetes mellitus. A cross-sectional study at the Harris Birthright Research Centre for Fetal Medicine, London, was performed. In 32 pregnancies complicated by maternal diabetes mellitus cordocentesis was performed at 36 to 39 weeks' gestation for the measurement of umbilical venous blood pH, PO2, PCO2, lactate, and glucose concentration; plasma insulin immunoreactivity; and insulin/glucose ratio. A reference range for plasma insulin and insulin/glucose ratio was constructed by studying fetal blood samples from 80 women who did not have diabetes mellitus. Mean umbilical venous blood pH was significantly lower and plasma insulin immunoreactivity and insulin/glucose ratio were significantly higher than the appropriate normal mean for gestation. There were significant associations between (1) maternal and fetal blood glucose concentrations (r = 0.95, p < 0.0001), (2) fetal blood glucose and plasma insulin immunoreactivity (r = 0.57, p < 0.01), (3) fetal plasma insulin immunoreactivity and blood pH (r = -0.39, p < 0.05), and (4) fetal insulin/glucose ratio and degree of macrosomia (r = 0.76, p < 0.0001). Fetal pancreatic beta-cell hyperplasia is implicated in the pathogenesis of both fetal acidemia and macrosomia.

  11. Positron emission tomography study on pancreatic somatostatin receptors in normal and diabetic rats with 68Ga-DOTA-octreotide: a potential PET tracer for beta cell mass measurement.

    Science.gov (United States)

    Sako, Takeo; Hasegawa, Koki; Nishimura, Mie; Kanayama, Yousuke; Wada, Yasuhiro; Hayashinaka, Emi; Cui, Yilong; Kataoka, Yosky; Senda, Michio; Watanabe, Yasuyoshi

    2013-12-06

    Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia, and the loss or dysfunction of pancreatic beta cells has been reported before the appearance of clinical symptoms and hyperglycemia. To evaluate beta cell mass (BCM) for improving the detection and treatment of DM at earlier stages, we focused on somatostatin receptors that are highly expressed in the pancreatic beta cells, and developed a positron emission tomography (PET) probe derived from octreotide, a metabolically stable somatostatin analog. Octreotide was conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), a chelating agent, and labeled with (68)Gallium ((68)Ga). After intravenous injection of (68)Ga-DOTA-octreotide, a 90-min emission scan of the abdomen was performed in normal and DM model rats. The PET studies showed that (68)Ga-DOTA-octreotide radioactivity was highly accumulated in the pancreas of normal rats and that the pancreatic accumulation was significantly reduced in the rats administered with an excess amount of unlabeled octreotide or after treatment with streptozotocin, which was used for the chemical induction of DM in rats. These results were in good agreement with the ex vivo biodistribution data. These results indicated that the pancreatic accumulation of (68)Ga-DOTA-octreotide represented specific binding to the somatostatin receptors and reflected BCM. Therefore, PET imaging with (68)Ga-DOTA-octreotide could be a potential tool for evaluating BCM. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Role of transcription factor KLF11 and its diabetes-associated gene variants in pancreatic beta cell function

    DEFF Research Database (Denmark)

    Neve, Bernadette; Fernandez-Zapico, Martin E; Ashkenazi-Katalan, Vered

    2005-01-01

    in beta cells. Genetic analysis of the KLF11 gene revealed two rare variants (Ala347Ser and Thr220Met) that segregate with diabetes in families with early-onset type 2 diabetes, and significantly impair its transcriptional activity. In addition, analysis of 1,696 type 2 diabetes mellitus and 1......,776 normoglycemic subjects show a frequent polymorphic Gln62Arg variant that significantly associates with type 2 diabetes mellitus in North European populations (OR = 1.29, P = 0.00033). Moreover, this variant alters the corepressor mSin3A-binding activity of KLF11, impairs the activation of the insulin promoter...... and shows lower levels of insulin expression in pancreatic beta cells. In addition, subjects carrying the Gln62Arg allele show decreased plasma insulin after an oral glucose challenge. Interestingly, all three nonsynonymous KLF11 variants show increased repression of the catalase 1 promoter, suggesting...

  13. Pancreatic differentiation of Pdx1-GFP reporter mouse induced pluripotent stem cells.

    Science.gov (United States)

    Porciuncula, Angelo; Kumar, Anujith; Rodriguez, Saray; Atari, Maher; Araña, Miriam; Martin, Franz; Soria, Bernat; Prosper, Felipe; Verfaillie, Catherine; Barajas, Miguel

    2016-12-01

    Efficient induction of defined lineages in pluripotent stem cells constitutes the determinant step for the generation of therapeutically relevant replacement cells to potentially treat a wide range of diseases, including diabetes. Pancreatic differentiation has remained an important challenge in large part because of the need to differentiate uncommitted pluripotent stem cells into highly specialized hormone-secreting cells, which has been shown to require a developmentally informed step-by-step induction procedure. Here, in the framework of using induced pluripotent stem cells (iPSCs) to generate pancreatic cells for pancreatic diseases, we have generated and characterized iPSCs from Pdx1-GFP transgenic mice. The use of a GFP reporter knocked into the endogenous Pdx1 promoter allowed us to monitor pancreatic induction based on the expression of Pdx1, a pancreatic master transcription factor, and to isolate a pure Pdx1-GFP + population for downstream applications. Differentiated cultures timely expressed markers specific to each stage and end-stage progenies acquired a rather immature beta-cell phenotype, characterized by polyhormonal expression even among cells highly expressing the Pdx1-GFP reporter. Our findings highlight the utility of employing a fluorescent protein reporter under the control of a master developmental gene in order to devise novel differentiation protocols for relevant cell types for degenerative diseases such as pancreatic beta cells for diabetes. Copyright © 2016 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  14. On the coherent behavior of pancreatic beta cell clusters

    Energy Technology Data Exchange (ETDEWEB)

    Loppini, Alessandro, E-mail: a.loppini@unicampus.it [Nonlinear Physics and Mathematical Modeling Lab, University Campus Bio-Medico, Via A. del Portillo 21, I-00128 Rome (Italy); Capolupo, Antonio, E-mail: capolupo@sa.infn.it [Physics Department, University of Salerno, Fisciano, 84084 (Italy); Cherubini, Christian, E-mail: c.cherubini@unicampus.it [Nonlinear Physics and Mathematical Modeling Lab, University Campus Bio-Medico, Via A. del Portillo 21, I-00128 Rome (Italy); International Center for Relativistic Astrophysics, University Campus Bio-Medico, Via A. del Portillo 21, I-00128, Rome (Italy); Gizzi, Alessio, E-mail: a.gizzi@unicampus.it [Nonlinear Physics and Mathematical Modeling Lab, University Campus Bio-Medico, Via A. del Portillo 21, I-00128 Rome (Italy); Bertolaso, Marta, E-mail: m.bertolaso@unicampus.it [Faculty of Engineering and Institute of Philosophy of Scientific and Technological Practice, University Campus Bio-Medico, Via A. del Portillo 21, I-00128 Rome (Italy); Filippi, Simonetta, E-mail: s.filippi@unicampus.it [Nonlinear Physics and Mathematical Modeling Lab, University Campus Bio-Medico, Via A. del Portillo 21, I-00128 Rome (Italy); International Center for Relativistic Astrophysics, University Campus Bio-Medico, Via A. del Portillo 21, I-00128, Rome (Italy); Vitiello, Giuseppe, E-mail: vitiello@sa.infn.it [Physics Department, University of Salerno, Fisciano, 84084 (Italy)

    2014-09-12

    Beta cells in pancreas represent an example of coupled biological oscillators which via communication pathways, are able to synchronize their electrical activity, giving rise to pulsatile insulin release. In this work we numerically analyze scale free self-similarity features of membrane voltage signal power density spectrum, through a stochastic dynamical model for beta cells in the islets of Langerhans fine tuned on mouse experimental data. Adopting the algebraic approach of coherent state formalism, we show how coherent molecular domains can arise from proper functional conditions leading to a parallelism with “phase transition” phenomena of field theory. - Highlights: • Beta cells in pancreas are coupled oscillators able to synchronize their activity. • We analyze scale free self-similarity features for beta cells. • We adopt the algebraic approach of coherent state formalism. • We show that coherent molecular domains arise from functional conditions.

  15. The Importance of REST for Development and Function of Beta Cells

    DEFF Research Database (Denmark)

    Martin, David; Grapin-Botton, Anne

    2017-01-01

    that are crucial for both neuronal and pancreatic endocrine function, through the recruitment of multiple transcriptional and epigenetic co-regulators. REST targets include genes encoding transcription factors, proteins involved in exocytosis, synaptic transmission or ion channeling, and non-coding RNAs. REST......Beta cells are defined by the genes they express, many of which are specific to this cell type, and ensure a specific set of functions. Beta cells are also defined by a set of genes they should not express (in order to function properly), and these genes have been called forbidden genes. Among...... these, the transcriptional repressor RE-1 Silencing Transcription factor (REST) is expressed in most cells of the body, excluding most populations of neurons, as well as pancreatic beta and alpha cells. In the cell types where it is expressed, REST represses the expression of hundreds of genes...

  16. Role of bone marrow cells in the development of pancreatic fibrosis in a rat model of pancreatitis induced by a choline-deficient/ethionine-supplemented diet

    Energy Technology Data Exchange (ETDEWEB)

    Akita, Shingo; Kubota, Koji [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Kobayashi, Akira, E-mail: kbys@shinshu-u.ac.jp [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Misawa, Ryosuke; Shimizu, Akira; Nakata, Takenari; Yokoyama, Takahide [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Takahashi, Masafumi [Center for Molecular Medicine Division of Bioimaging Sciences, Jichi Medical University, 3311-1 Yakushiji, Shimono, Tochigi 329-0498 (Japan); Miyagawa, Shinichi [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

    2012-04-20

    Highlights: Black-Right-Pointing-Pointer BMC-derived PSCs play a role in a rat CDE diet-induced pancreatitis model. Black-Right-Pointing-Pointer BMC-derived PSCs contribute mainly to the early stage of pancreatic fibrosis. Black-Right-Pointing-Pointer BMC-derived activated PSCs can produce PDGF and TGF {beta}1. -- Abstract: Bone marrow cell (BMC)-derived myofibroblast-like cells have been reported in various organs, including the pancreas. However, the contribution of these cells to pancreatic fibrosis has not been fully discussed. The present study examined the possible involvement of pancreatic stellate cells (PSCs) originating from BMCs in the development of pancreatic fibrosis in a clinically relevant rat model of acute pancreatitis induced by a choline-deficient/ethionine-supplemented (CDE) diet. BMCs from female transgenic mice ubiquitously expressing green fluorescent protein (GFP) were transplanted into lethally irradiated male rats. Once chimerism was established, acute pancreatitis was induced by a CDE diet. Chronological changes in the number of PSCs originating from the donor BMCs were examined using double immunofluorescence for GFP and markers for PSCs, such as desmin and alpha smooth muscle actin ({alpha}SMA), 1, 3 and 8 weeks after the initiation of CDE feeding. We also used immunohistochemical staining to evaluate whether the PSCs from the BMCs produce growth factors, such as platelet-derived growth factor (PDGF) and transforming growth factor (TGF) {beta}1. The percentage of BMC-derived activated PSCs increased significantly, peaking after 1 week of CDE treatment (accounting for 23.3 {+-} 0.9% of the total population of activated PSCs) and then decreasing. These cells produced both PDGF and TGF{beta}1 during the early stage of pancreatic fibrosis. Our results suggest that PSCs originating from BMCs contribute mainly to the early stage of pancreatic injury, at least in part, by producing growth factors in a rat CDE diet-induced pancreatitis model.

  17. Beta-cell lines derived from transgenic mice expressing a hybrid insulin gene-oncogene

    DEFF Research Database (Denmark)

    Efrat, S; Linde, S; Kofod, Hans

    1988-01-01

    Three pancreatic beta-cell lines have been established from insulinomas derived from transgenic mice carrying a hybrid insulin-promoted simian virus 40 tumor antigen gene. The beta tumor cell (beta TC) lines maintain the features of differentiated beta cells for about 50 passages in culture. The ...... both to immortalize a rare cell type and to provide a selection for the maintenance of its differentiated phenotype....

  18. Chronology of endocrine differentiation and beta-cell neogenesis.

    Science.gov (United States)

    Miyatsuka, Takeshi

    2016-01-01

    Diabetes is a chronic and incurable disease, which results from absolute or relative insulin insufficiency. Therefore, pancreatic beta cells, which are the only type of cell that expresses insulin, is considered to be a potential target for the cure of diabetes. Although the findings regarding beta-cell neogenesis during pancreas development have been exploited to induce insulin-producing cells from non-beta cells, there are still many hurdles towards generating fully functional beta cells that can produce high levels of insulin and respond to physiological signals. To overcome these problems, a solid understanding of pancreas development and beta-cell formation is required, and several mouse models have been developed to reveal the unique features of each endocrine cell type at distinct developmental time points. Here I review our understanding of pancreas development and endocrine differentiation focusing on recent progresses in improving temporal cell labeling in vivo.

  19. Insulin-producing cells generated from dedifferentiated human pancreatic beta cells expanded in vitro.

    Directory of Open Access Journals (Sweden)

    Holger A Russ

    Full Text Available Expansion of beta cells from the limited number of adult human islet donors is an attractive prospect for increasing cell availability for cell therapy of diabetes. However, attempts at expanding human islet cells in tissue culture result in loss of beta-cell phenotype. Using a lineage-tracing approach we provided evidence for massive proliferation of beta-cell-derived (BCD cells within these cultures. Expansion involves dedifferentiation resembling epithelial-mesenchymal transition (EMT. Epigenetic analyses indicate that key beta-cell genes maintain open chromatin structure in expanded BCD cells, although they are not transcribed. Here we investigated whether BCD cells can be redifferentiated into beta-like cells.Redifferentiation conditions were screened by following activation of an insulin-DsRed2 reporter gene. Redifferentiated cells were characterized for gene expression, insulin content and secretion assays, and presence of secretory vesicles by electron microscopy. BCD cells were induced to redifferentiate by a combination of soluble factors. The redifferentiated cells expressed beta-cell genes, stored insulin in typical secretory vesicles, and released it in response to glucose. The redifferentiation process involved mesenchymal-epithelial transition, as judged by changes in gene expression. Moreover, inhibition of the EMT effector SLUG (SNAI2 using shRNA resulted in stimulation of redifferentiation. Lineage-traced cells also gave rise at a low rate to cells expressing other islet hormones, suggesting transition of BCD cells through an islet progenitor-like stage during redifferentiation.These findings demonstrate for the first time that expanded dedifferentiated beta cells can be induced to redifferentiate in culture. The findings suggest that ex-vivo expansion of adult human islet cells is a promising approach for generation of insulin-producing cells for transplantation, as well as basic research, toxicology studies, and drug

  20. Fetal and neonatal nicotine exposure in Wistar rats causes progressive pancreatic mitochondrial damage and beta cell dysfunction.

    Directory of Open Access Journals (Sweden)

    Jennifer E Bruin

    Full Text Available Nicotine replacement therapy (NRT is currently recommended as a safe smoking cessation aid for pregnant women. However, fetal and neonatal nicotine exposure in rats causes mitochondrial-mediated beta cell apoptosis at weaning, and adult-onset dysglycemia, which we hypothesize is related to progressive mitochondrial dysfunction in the pancreas. Therefore in this study we examined the effect of fetal and neonatal exposure to nicotine on pancreatic mitochondrial structure and function during postnatal development. Female Wistar rats were given saline (vehicle control or nicotine bitartrate (1 mg/kg/d via subcutaneous injection for 2 weeks prior to mating until weaning. At 3-4, 15 and 26 weeks of age, oral glucose tolerance tests were performed, and pancreas tissue was collected for electron microscopy, enzyme activity assays and islet isolation. Following nicotine exposure mitochondrial structural abnormalities were observed beginning at 3 weeks and worsened with advancing age. Importantly the appearance of these structural defects in nicotine-exposed animals preceded the onset of glucose intolerance. Nicotine exposure also resulted in significantly reduced pancreatic respiratory chain enzyme activity, degranulation of beta cells, elevated islet oxidative stress and impaired glucose-stimulated insulin secretion compared to saline controls at 26 weeks of age. Taken together, these data suggest that maternal nicotine use during pregnancy results in postnatal mitochondrial dysfunction that may explain, in part, the dysglycemia observed in the offspring from this animal model. These results clearly indicate that further investigation into the safety of NRT use during pregnancy is warranted.

  1. Transplantation of Human Pancreatic Endoderm Cells Reverses Diabetes Post Transplantation in a Prevascularized Subcutaneous Site

    Directory of Open Access Journals (Sweden)

    Andrew R. Pepper

    2017-06-01

    Full Text Available Beta-cell replacement therapy is an effective means to restore glucose homeostasis in select humans with autoimmune diabetes. The scarcity of “healthy” human donor pancreata restricts the broader application of this effective curative therapy. “β-Like” cells derived from human embryonic stem cells (hESC, with the capacity to secrete insulin in a glucose-regulated manner, have been developed in vitro, with limitless capacity for expansion. Here we report long-term diabetes correction in mice transplanted with hESC-derived pancreatic endoderm cells (PECs in a prevascularized subcutaneous site. This advancement mitigates chronic foreign-body response, utilizes a device- and growth factor-free approach, facilitates in vivo differentiation of PECs into glucose-responsive insulin-producing cells, and reliably restores glycemic control. Basal and stimulated human C-peptide secretion was detected throughout the study, which was abolished upon graft removal. Recipient mice demonstrated physiological clearance of glucose in response to metabolic challenge and safely retrieved grafts contained viable glucose regulatory cells.

  2. Regulation of Pancreatic β Cell Mass by Cross-Interaction between CCAAT Enhancer Binding Protein β Induced by Endoplasmic Reticulum Stress and AMP-Activated Protein Kinase Activity.

    Directory of Open Access Journals (Sweden)

    Tomokazu Matsuda

    Full Text Available During the development of type 2 diabetes, endoplasmic reticulum (ER stress leads to not only insulin resistance but also to pancreatic beta cell failure. Conversely, cell function under various stressed conditions can be restored by reducing ER stress by activating AMP-activated protein kinase (AMPK. However, the details of this mechanism are still obscure. Therefore, the current study aims to elucidate the role of AMPK activity during ER stress-associated pancreatic beta cell failure. MIN6 cells were loaded with 5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide (AICAR and metformin to assess the relationship between AMPK activity and CCAAT enhancer binding protein β (C/EBPβ expression levels. The effect of C/EBPβ phosphorylation on expression levels was also investigated. Vildagliptin and metformin were administered to pancreatic beta cell-specific C/EBPβ transgenic mice to investigate the relationship between C/EBPβ expression levels and AMPK activity in the pancreatic islets. When pancreatic beta cells are exposed to ER stress, the accumulation of the transcription factor C/EBPβ lowers the AMP/ATP ratio, thereby decreasing AMPK activity. In an opposite manner, incubation of MIN6 cells with AICAR or metformin activated AMPK, which suppressed C/EBPβ expression. In addition, administration of the dipeptidyl peptidase-4 inhibitor vildagliptin and metformin to pancreatic beta cell-specific C/EBPβ transgenic mice decreased C/EBPβ expression levels and enhanced pancreatic beta cell mass in proportion to the recovery of AMPK activity. Enhanced C/EBPβ expression and decreased AMPK activity act synergistically to induce ER stress-associated pancreatic beta cell failure.

  3. [Relationship between the expression of beta-cat, cyclin D1 and c-myc and the occurance and biological behavior of pancreatic cancer].

    Science.gov (United States)

    Li, Yu-jun; Ji, Xiang-rui

    2003-06-01

    To study the relationship between the abnormal expression of beta-catenin (beta-cat) and the high expressions of cyclin D1 and c-myc and the occurance, proliferation, infiltration, metastasis and prognosis of pancreatic cancer, and to provide rational basis for the clinical diagnosis and treatment. Immunohistochemical PicTure trade mark was used to examine the expressions of beta-cat, cyclin D1 and c-myc in 47 cases of the cancerous tissue of pancreas, 12 cases of the pancreatic intraepithelial neoplasia and 10 cases of normal tissue of pancreas, respectively. Pancreatic cancer proliferation cell nuclear antigen (PCNA) was also tested as the index of the extent of proliferation of the pancreatic cancer. beta-cat was expressed normally in the 10 cases of the normal pancreatic tissue, while cyclin D1 and c-myc were negative. The expression rates of beta-cat, cyclin D1 and c-myc in the tissues of the pancreatic intraepithelial neoplasia and the pancreatic cancer had no significant difference [6/12 and 68.1% (32/47), 6/12 and 74.5% (35/47), 5/12 and 70.2% (33/47) respectively;P values were all more than 0.05]. The abnormal expression rate of beta-cat was significantly correlated to the metastasis of the pancreatic cancer and the one-year survival rate (both P 0.05). The expression rate of cyclin D1 was correlated with the proliferation of the pancreatic cancer and the extent of differentiation (both P 0.05). The expression rate of c-myc was not correlated with the size, the extent of proliferation, infiltration, metastasis, or one-year survival rate (both P > 0.05), but closely with the proliferation activity of the cancerous tissue of pancreas (P < 0.05). The abnormal expression of beta-cat and the high expressions of cyclin D1 and c-myc had a parallel relationship with the pancreatic intraepithelial neoplasia and pancreatic cancer (both P < 0.05, gamma = 1.000, 0.845, 0.437, 0.452). The abnormal expression of beta-cat activates cyclin D1 and c-myc, and results in the

  4. Transforming growth factor beta-activated kinase 1 (TAK1)-dependent checkpoint in the survival of dendritic cells promotes immune homeostasis and function.

    Science.gov (United States)

    Wang, Yanyan; Huang, Gonghua; Vogel, Peter; Neale, Geoffrey; Reizis, Boris; Chi, Hongbo

    2012-02-07

    Homeostatic control of dendritic cell (DC) survival is crucial for adaptive immunity, but the molecular mechanism is not well defined. Moreover, how DCs influence immune homeostasis under steady state remains unclear. Combining DC-specific and -inducible deletion systems, we report that transforming growth factor beta-activated kinase 1 (TAK1) is an essential regulator of DC survival and immune system homeostasis and function. Deficiency of TAK1 in CD11c(+) cells induced markedly elevated apoptosis, leading to the depletion of DC populations, especially the CD8(+) and CD103(+) DC subsets in lymphoid and nonlymphoid tissues, respectively. TAK1 also contributed to DC development by promoting the generation of DC precursors. Prosurvival signals from Toll-like receptors, CD40 and receptor activator of nuclear factor-κB (RANK) are integrated by TAK1 in DCs, which in turn mediated activation of downstream NF-κB and AKT-Foxo pathways and established a gene-expression program. TAK1 deficiency in DCs caused a myeloid proliferative disorder characterized by expansion of neutrophils and inflammatory monocytes, disrupted T-cell homeostasis, and prevented effective T-cell priming and generation of regulatory T cells. Moreover, TAK1 signaling in DCs was required to prevent myeloid proliferation even in the absence of lymphocytes, indicating a previously unappreciated regulatory mechanism of DC-mediated control of myeloid cell-dependent inflammation. Therefore, TAK1 orchestrates a prosurvival checkpoint in DCs that affects the homeostasis and function of the immune system.

  5. Pancreatic stellate cells enhance stem cell-like phenotypes in pancreatic cancer cells

    International Nuclear Information System (INIS)

    Hamada, Shin; Masamune, Atsushi; Takikawa, Tetsuya; Suzuki, Noriaki; Kikuta, Kazuhiro; Hirota, Morihisa; Hamada, Hirofumi; Kobune, Masayoshi; Satoh, Kennichi; Shimosegawa, Tooru

    2012-01-01

    Highlights: ► Pancreatic stellate cells (PSCs) promote the progression of pancreatic cancer. ► Pancreatic cancer cells co-cultured with PSCs showed enhanced spheroid formation. ► Expression of stem cell-related genes ABCG2, Nestin and LIN28 was increased. ► Co-injection of PSCs enhanced tumorigenicity of pancreatic cancer cells in vivo. ► This study suggested a novel role of PSCs as a part of the cancer stem cell niche. -- Abstract: The interaction between pancreatic cancer cells and pancreatic stellate cells (PSCs), a major profibrogenic cell type in the pancreas, is receiving increasing attention. There is accumulating evidence that PSCs promote the progression of pancreatic cancer by increasing cancer cell proliferation and invasion as well as by protecting them from radiation- and gemcitabine-induced apoptosis. Recent studies have identified that a portion of cancer cells, called “cancer stem cells”, within the entire cancer tissue harbor highly tumorigenic and chemo-resistant phenotypes, which lead to the recurrence after surgery or re-growth of the tumor. The mechanisms that maintain the “stemness” of these cells remain largely unknown. We hypothesized that PSCs might enhance the cancer stem cell-like phenotypes in pancreatic cancer cells. Indirect co-culture of pancreatic cancer cells with PSCs enhanced the spheroid-forming ability of cancer cells and induced the expression of cancer stem cell-related genes ABCG2, Nestin and LIN28. In addition, co-injection of PSCs enhanced tumorigenicity of pancreatic cancer cells in vivo. These results suggested a novel role of PSCs as a part of the cancer stem cell niche.

  6. Chaperones ameliorate beta cell dysfunction associated with human islet amyloid polypeptide overexpression.

    Directory of Open Access Journals (Sweden)

    Lisa Cadavez

    Full Text Available In type 2 diabetes, beta-cell dysfunction is thought to be due to several causes, one being the formation of toxic protein aggregates called islet amyloid, formed by accumulations of misfolded human islet amyloid polypeptide (hIAPP. The process of hIAPP misfolding and aggregation is one of the factors that may activate the unfolded protein response (UPR, perturbing endoplasmic reticulum (ER homeostasis. Molecular chaperones have been described to be important in regulating ER response to ER stress. In the present work, we evaluate the role of chaperones in a stressed cellular model of hIAPP overexpression. A rat pancreatic beta-cell line expressing hIAPP exposed to thapsigargin or treated with high glucose and palmitic acid, both of which are known ER stress inducers, showed an increase in ER stress genes when compared to INS1E cells expressing rat IAPP or INS1E control cells. Treatment with molecular chaperone glucose-regulated protein 78 kDa (GRP78, also known as BiP or protein disulfite isomerase (PDI, and chemical chaperones taurine-conjugated ursodeoxycholic acid (TUDCA or 4-phenylbutyrate (PBA, alleviated ER stress and increased insulin secretion in hIAPP-expressing cells. Our results suggest that the overexpression of hIAPP induces a stronger response of ER stress markers. Moreover, endogenous and chemical chaperones are able to ameliorate induced ER stress and increase insulin secretion, suggesting that improving chaperone capacity can play an important role in improving beta-cell function in type 2 diabetes.

  7. Lysine deacetylase inhibition prevents diabetes by chromatin-independent immunoregulation and beta-cell protection

    NARCIS (Netherlands)

    Christensen, D.P.; Gysemans, C.; Lundh, M.; Dahllof, M.S.; Noesgaard, D.; Schmidt, S.F.; Mandrup, S; Birkbak, N.; Workman, C.T.; Piemonti, L.; Blaabjerg, L.; Monzani, V.; Fossati, G.; Mascagni, P.; Paraskevas, S.; Aikin, R.A.; Billestrup, N.; Grunnet, L.G.; Dinarello, C.A.; Mathieu, C.; Mandrup-Poulsen, T.

    2014-01-01

    Type 1 diabetes is due to destruction of pancreatic beta-cells. Lysine deacetylase inhibitors (KDACi) protect beta-cells from inflammatory destruction in vitro and are promising immunomodulators. Here we demonstrate that the clinically well-tolerated KDACi vorinostat and givinostat revert diabetes

  8. Development of biomarker specific of pancreatic beta cells (incretin radiolabelled) for image of beta functional mass in diabetic and obese: study in animal model; Desenvolvimento de biomarcador específico de células beta pancreáticas (incretina radiomarcada) para imagem da massa beta funcional em diabéticos e obesos: estudo em modelo animal

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Daniele

    2017-07-01

    Increased prevalence of obesity worldwide, has become a vast concern, stimulating investigations focusing prevention and therapy of this condition. The association of type 2 diabetes or insulin resistance aggravates the prognosis of obesity. Even patients successfully submitted to bariatric or metabolic surgery, may not be cured of diabetes, as improvement of circulating values of glucose and insulin not necessarily reflects recovery of pancreatic beta cell mass. There is no consensus about how to estimate beta cell mass in vivo. Available tools suffer from low sensitivity and specificity, often being as well cumbersome and expensive. Radiolabeled incretins, such as glucagon-like-peptide 1 (GLP-1) analogs, seem to be promising options for the measurement of beta cell mass in diabetes and insulinoma. The objective of this study was the development of two conjugates of GLP-1 analog, radiolabeled with {sup 99m} Technetium, as a noninvasive imaging method for the estimation of pancreatic beta cell mass, in the presence of obesity. Animal models were selected, including hyperlipidic diet-induced obesity, diet restricted obesity, and as controls, alloxan diabetes. Results indicated that both radiotracers achieved over 97% radiochemical yield. The most successful product was {sup 99m}Tc-HYNIC-βAla-Exendin-4. Low beta cell mass uptake occurred in diet-induced obesity. Diet-restricted obesity, with substantial shedding of excess body weight, was followed by remarkable decrease of fasting blood glucose, however beta cell mass uptake was only mildly improved. Future studies are recommended in obesity, type 2 diabetes, and dieting, including bariatric and metabolic operations. (author)

  9. Carriers of loss-of-function mutations in EXT display impaired pancreatic beta-cell reserve due to smaller pancreas volume.

    Directory of Open Access Journals (Sweden)

    Sophie J Bernelot Moens

    Full Text Available Exotosin (EXT proteins are involved in the chain elongation step of heparan sulfate (HS biosynthesis, which is intricately involved in organ development. Loss of function mutations (LOF in EXT1 and EXT2 result in hereditary exostoses (HME. Interestingly, HS plays a role in pancreas development and beta-cell function, and genetic variations in EXT2 are associated with an increased risk for type 2 diabetes mellitus. We hypothesized that loss of function of EXT1 or EXT2 in subjects with hereditary multiple exostoses (HME affects pancreatic insulin secretion capacity and development. We performed an oral glucose tolerance test (OGTT followed by hyperglycemic clamps to investigate first-phase glucose-stimulated insulin secretion (GSIS in HME patients and age and gender matched non-affected relatives. Pancreas volume was assessed with magnetic resonance imaging (MRI. OGTT did not reveal significant differences in glucose disposal, but there was a markedly lower GSIS in HME subjects during hyperglycemic clamp (iAUC HME: 0.72 [0.46-1.16] vs. controls 1.53 [0.69-3.36] nmol·l-1·min-1, p<0.05. Maximal insulin response following arginine challenge was also significantly attenuated (iAUC HME: 7.14 [4.22-10.5] vs. controls 10.2 [7.91-12.70] nmol·l-1·min-1 p<0.05, indicative of an impaired beta-cell reserve. MRI revealed a significantly smaller pancreatic volume in HME subjects (HME: 72.0±15.8 vs. controls 96.5±26.0 cm3 p = 0.04. In conclusion, loss of function of EXT proteins may affect beta-cell mass and insulin secretion capacity in humans, and render subjects at a higher risk of developing type 2 diabetes when exposed to environmental risk factors.

  10. Transcriptomic profiling of pancreatic alpha, beta and delta cell populations identifies delta cells as a principal target for ghrelin in mouse islets

    DEFF Research Database (Denmark)

    Adriaenssens, Alice E; Svendsen, Berit; Lam, Brian Y H

    2016-01-01

    cytometry and analysed by RNA sequencing. The role of the ghrelin receptor was validated by imaging delta cell calcium concentrations using islets with delta cell restricted expression of the calcium reporter GCaMP3, and in perfused mouse pancreases. RESULTS: A database was constructed of all genes...... expressed in alpha, beta and delta cells. The gene encoding the ghrelin receptor, Ghsr, was highlighted as being highly expressed and enriched in delta cells. Activation of the ghrelin receptor raised cytosolic calcium levels in primary pancreatic delta cells and enhanced somatostatin secretion in perfused...... pancreases, correlating with a decrease in insulin and glucagon release. The inhibition of insulin secretion by ghrelin was prevented by somatostatin receptor antagonism. CONCLUSIONS/INTERPRETATION: Our transcriptomic database of genes expressed in the principal islet cell populations will facilitate...

  11. Pancreatic stellate cells promote epithelial-mesenchymal transition in pancreatic cancer cells

    International Nuclear Information System (INIS)

    Kikuta, Kazuhiro; Masamune, Atsushi; Watanabe, Takashi; Ariga, Hiroyuki; Itoh, Hiromichi; Hamada, Shin; Satoh, Kennichi; Egawa, Shinichi; Unno, Michiaki; Shimosegawa, Tooru

    2010-01-01

    Research highlights: → Recent studies have shown that pancreatic stellate cells (PSCs) promote the progression of pancreatic cancer. → Pancreatic cancer cells co-cultured with PSCs showed loose cell contacts and scattered, fibroblast-like appearance. → PSCs decreased the expression of epithelial markers but increased that of mesenchymal markers, along with increased migration. → This study suggests epithelial-mesenchymal transition as a novel mechanism by which PSCs contribute to the aggressive behavior of pancreatic cancer cells. -- Abstract: The interaction between pancreatic cancer cells and pancreatic stellate cells (PSCs), a major profibrogenic cell type in the pancreas, is receiving increasing attention. There is accumulating evidence that PSCs promote the progression of pancreatic cancer by increasing cancer cell proliferation and invasion as well as by protecting them from radiation- and gemcitabine-induced apoptosis. Because epithelial-mesenchymal transition (EMT) plays a critical role in the progression of pancreatic cancer, we hypothesized that PSCs promote EMT in pancreatic cancer cells. Panc-1 and SUIT-2 pancreatic cancer cells were indirectly co-cultured with human PSCs isolated from patients undergoing operation for pancreatic cancer. The expression of epithelial and mesenchymal markers was examined by real-time PCR and immunofluorescent staining. The migration of pancreatic cancer cells was examined by scratch and two-chamber assays. Pancreatic cancer cells co-cultured with PSCs showed loose cell contacts and a scattered, fibroblast-like appearance. The expression of E-cadherin, cytokeratin 19, and membrane-associated β-catenin was decreased, whereas vimentin and Snail (Snai-1) expression was increased more in cancer cells co-cultured with PSCs than in mono-cultured cells. The migration of pancreatic cancer cells was increased by co-culture with PSCs. The PSC-induced decrease of E-cadherin expression was not altered by treatment with anti

  12. Central effects of beta-endorphins on glucose homeostasis in the conscious dog

    International Nuclear Information System (INIS)

    Radosevich, P.M.; Lacy, D.B.; Brown, L.L.; Williams, P.E.; Abumrad, N.N.

    1989-01-01

    The effects of centrally administered beta-endorphins on glucose homeostasis in the conscious dog were studied. Intracerebroventricular administration of beta-endorphin (0.2 mg/h) caused a 70% increase in plasma glucose. The mechanism of the hyperglycemia was twofold: there was an early increase in glucose production and a late inhibition of glucose clearance. These changes are explained by marked increases in plasma epinephrine (30-fold) and norepinephrine (6-fold) that occurred during infusion of beta-endorphin. Central administration of beta-endorphin also resulted in increased levels of adrenocorticotropic hormone and cortisol. In addition there was an increase in plasma insulin but no increase in plasma glucagon. Intravenous administration of beta-endorphin did not alter glucose homeostasis. Intracerebroventricular administration of acetylated beta-endorphin did not perturb glucose kinetics or any of the hormones that changed during infusion of the unacetylated peptide. We conclude that beta-endorphin acts centrally to cause hyperglycemia by stimulating sympathetic outflow and the pituitary-adrenal axis. Acetylation of beta-endorphin abolishes the in vivo activity of the peptide

  13. Central effects of beta-endorphins on glucose homeostasis in the conscious dog

    Energy Technology Data Exchange (ETDEWEB)

    Radosevich, P.M.; Lacy, D.B.; Brown, L.L.; Williams, P.E.; Abumrad, N.N.

    1989-02-01

    The effects of centrally administered beta-endorphins on glucose homeostasis in the conscious dog were studied. Intracerebroventricular administration of beta-endorphin (0.2 mg/h) caused a 70% increase in plasma glucose. The mechanism of the hyperglycemia was twofold: there was an early increase in glucose production and a late inhibition of glucose clearance. These changes are explained by marked increases in plasma epinephrine (30-fold) and norepinephrine (6-fold) that occurred during infusion of beta-endorphin. Central administration of beta-endorphin also resulted in increased levels of adrenocorticotropic hormone and cortisol. In addition there was an increase in plasma insulin but no increase in plasma glucagon. Intravenous administration of beta-endorphin did not alter glucose homeostasis. Intracerebroventricular administration of acetylated beta-endorphin did not perturb glucose kinetics or any of the hormones that changed during infusion of the unacetylated peptide. We conclude that beta-endorphin acts centrally to cause hyperglycemia by stimulating sympathetic outflow and the pituitary-adrenal axis. Acetylation of beta-endorphin abolishes the in vivo activity of the peptide.

  14. Characterization of primary cilia and Hedgehog signaling during development of the human pancreas and in human pancreatic duct cancer cell lines

    DEFF Research Database (Denmark)

    Nielsen, Sonja K; Møllgård, Kjeld; Clement, Christian A

    2008-01-01

    Hedgehog (Hh) signaling controls pancreatic development and homeostasis; aberrant Hh signaling is associated with several pancreatic diseases. Here we investigated the link between Hh signaling and primary cilia in the human developing pancreatic ducts and in cultures of human pancreatic duct...... adenocarcinoma cell lines, PANC-1 and CFPAC-1. We show that the onset of Hh signaling from human embryogenesis to fetal development is associated with accumulation of Hh signaling components Smo and Gli2 in duct primary cilia and a reduction of Gli3 in the duct epithelium. Smo, Ptc, and Gli2 localized to primary...... cilia of PANC-1 and CFPAC-1 cells, which may maintain high levels of nonstimulated Hh pathway activity. These findings indicate that primary cilia are involved in pancreatic development and postnatal tissue homeostasis....

  15. The physiology of rodent beta-cells in pancreas slices.

    Science.gov (United States)

    Rupnik, M

    2009-01-01

    Beta-cells in pancreatic islets form complex syncytia. Sufficient cell-to-cell electrical coupling seems to ensure coordinated depolarization pattern and insulin release that can be further modulated by rich innervation. The complex structure and coordinated action develop after birth during fast proliferation of the endocrine tissue. These emergent properties can be lost due to various reasons later in life and can lead to glucose intolerance and diabetes mellitus. Pancreas slice is a novel method of choice to study the physiology of beta-cells still embedded in their normal cellulo-social context. I present major advantages, list drawbacks and provide an overview on recent advances in our understanding of the physiology of beta-cells using the pancreas slice approach.

  16. AMP-activated protein kinase (AMPK mediates nutrient regulation of thioredoxin-interacting protein (TXNIP in pancreatic beta-cells.

    Directory of Open Access Journals (Sweden)

    Maayan Shaked

    Full Text Available Thioredoxin-interacting protein (TXNIP regulates critical biological processes including inflammation, stress and apoptosis. TXNIP is upregulated by glucose and is a critical mediator of hyperglycemia-induced beta-cell apoptosis in diabetes. In contrast, the saturated long-chain fatty acid palmitate, although toxic to the beta-cell, inhibits TXNIP expression. The mechanisms involved in the opposing effects of glucose and fatty acids on TXNIP expression are unknown. We found that both palmitate and oleate inhibited TXNIP in a rat beta-cell line and islets. Palmitate inhibition of TXNIP was independent of fatty acid beta-oxidation or esterification. AMP-activated protein kinase (AMPK has an important role in cellular energy sensing and control of metabolic homeostasis; therefore we investigated its involvement in nutrient regulation of TXNIP. As expected, glucose inhibited whereas palmitate stimulated AMPK. Pharmacologic activators of AMPK mimicked fatty acids by inhibiting TXNIP. AMPK knockdown increased TXNIP expression in presence of high glucose with and without palmitate, indicating that nutrient (glucose and fatty acids effects on TXNIP are mediated in part via modulation of AMPK activity. TXNIP is transcriptionally regulated by carbohydrate response element-binding protein (ChREBP. Palmitate inhibited glucose-stimulated ChREBP nuclear entry and recruitment to the Txnip promoter, thereby inhibiting Txnip transcription. We conclude that AMPK is an important regulator of Txnip transcription via modulation of ChREBP activity. The divergent effects of glucose and fatty acids on TXNIP expression result in part from their opposing effects on AMPK activity. In light of the important role of TXNIP in beta-cell apoptosis, its inhibition by fatty acids can be regarded as an adaptive/protective response to glucolipotoxicity. The finding that AMPK mediates nutrient regulation of TXNIP may have important implications for the pathophysiology and treatment

  17. Protein-Mediated Interactions of Pancreatic Islet Cells

    Directory of Open Access Journals (Sweden)

    Paolo Meda

    2013-01-01

    Full Text Available The islets of Langerhans collectively form the endocrine pancreas, the organ that is soley responsible for insulin secretion in mammals, and which plays a prominent role in the control of circulating glucose and metabolism. Normal function of these islets implies the coordination of different types of endocrine cells, noticeably of the beta cells which produce insulin. Given that an appropriate secretion of this hormone is vital to the organism, a number of mechanisms have been selected during evolution, which now converge to coordinate beta cell functions. Among these, several mechanisms depend on different families of integral membrane proteins, which ensure direct (cadherins, N-CAM, occludin, and claudins and paracrine communications (pannexins between beta cells, and between these cells and the other islet cell types. Also, other proteins (integrins provide communication of the different islet cell types with the materials that form the islet basal laminae and extracellular matrix. Here, we review what is known about these proteins and their signaling in pancreatic β-cells, with particular emphasis on the signaling provided by Cx36, given that this is the integral membrane protein involved in cell-to-cell communication, which has so far been mostly investigated for effects on beta cell functions.

  18. Cdk5 inhibitory peptide (CIP inhibits Cdk5/p25 activity induced by high glucose in pancreatic beta cells and recovers insulin secretion from p25 damage.

    Directory of Open Access Journals (Sweden)

    Ya-Li Zheng

    Full Text Available Cdk5/p25 hyperactivity has been demonstrated to lead to neuron apoptosis and degenerations. Chronic exposure to high glucose (HG results in hyperactivity of Cdk5 and reduced insulin secretion. Here, we set out to determine whether abnormal upregulation of Cdk5/p25 activity may be induced in a pancreatic beta cell line, Min6 cells. We first confirmed that p25 were induced in overexpressed p35 cells treated with HG and increased time course dependence. Next, we showed that no p25 was detected under short time HG stimulation (4-12 hrs, however was detectable in the long exposure in HG cells (24 hrs and 48 hrs. Cdk5 activity in the above cells was much higher than low glucose treated cells and resulted in more than 50% inhibition of insulin secretion. We confirmed these results by overexpression of p25 in Min6 cells. As in cortical neurons, CIP, a small peptide, inhibited Cdk5/p25 activity and restored insulin secretion. The same results were detected in co-infection of dominant negative Cdk5 (DNCdk5 with p25. CIP also reduced beta cells apoptosis induced by Cdk5/p25. These studies indicate that Cdk5/p25 hyperactivation deregulates insulin secretion and induces cell death in pancreatic beta cells and suggests that CIP may serve as a therapeutic agent for type 2 diabetes.

  19. Ethanol exerts dual effects on calcium homeostasis in CCK-8-stimulated mouse pancreatic acinar cells.

    Science.gov (United States)

    Fernández-Sánchez, Marcela; del Castillo-Vaquero, Angel; Salido, Ginés M; González, Antonio

    2009-10-30

    A significant percentage of patients with pancreatitis often presents a history of excessive alcohol consumption. Nevertheless, the patho-physiological effect of ethanol on pancreatitis remains poorly understood. In the present study, we have investigated the early effects of acute ethanol exposure on CCK-8-evoked Ca2+ signals in mouse pancreatic acinar cells. Changes in [Ca2+]i and ROS production were analyzed employing fluorescence techniques after loading cells with fura-2 or CM-H2DCFDA, respectively. Ethanol, in the concentration range from 1 to 50 mM, evoked an oscillatory pattern in [Ca2+]i. In addition, ethanol evoked reactive oxygen species generation (ROS) production. Stimulation of cells with 1 nM or 20 pM CCK-8, respectively led to a transient change and oscillations in [Ca2+]i. In the presence of ethanol a transformation of 20 pM CCK-8-evoked physiological oscillations into a single transient increase in [Ca2+]i in the majority of cells was observed. Whereas, in response to 1 nM CCK-8, the total Ca2+ mobilization was significantly increased by ethanol pre-treatment. Preincubation of cells with 1 mM 4-MP, an inhibitor of alcohol dehydrogenase, or 10 microM of the antioxidant cinnamtannin B-1, reverted the effect of ethanol on total Ca2+ mobilization evoked by 1 nM CCK-8. Cinnamtannin B-1 blocked ethanol-evoked ROS production. ethanol may lead, either directly or through ROS generation, to an over stimulation of pancreatic acinar cells in response to CCK-8, resulting in a higher Ca2+ mobilization compared to normal conditions. The actions of ethanol on CCK-8-stimulation of cells create a situation potentially leading to Ca2+ overload, which is a common pathological precursor that mediates pancreatitis.

  20. Ethanol exerts dual effects on calcium homeostasis in CCK-8-stimulated mouse pancreatic acinar cells

    Directory of Open Access Journals (Sweden)

    Salido Ginés M

    2009-10-01

    Full Text Available Abstract Background A significant percentage of patients with pancreatitis often presents a history of excessive alcohol consumption. Nevertheless, the patho-physiological effect of ethanol on pancreatitis remains poorly understood. In the present study, we have investigated the early effects of acute ethanol exposure on CCK-8-evoked Ca2+ signals in mouse pancreatic acinar cells. Changes in [Ca2+]i and ROS production were analyzed employing fluorescence techniques after loading cells with fura-2 or CM-H2DCFDA, respectively. Results Ethanol, in the concentration range from 1 to 50 mM, evoked an oscillatory pattern in [Ca2+]i. In addition, ethanol evoked reactive oxygen species generation (ROS production. Stimulation of cells with 1 nM or 20 pM CCK-8, respectively led to a transient change and oscillations in [Ca2+]i. In the presence of ethanol a transformation of 20 pM CCK-8-evoked physiological oscillations into a single transient increase in [Ca2+]i in the majority of cells was observed. Whereas, in response to 1 nM CCK-8, the total Ca2+ mobilization was significantly increased by ethanol pre-treatment. Preincubation of cells with 1 mM 4-MP, an inhibitor of alcohol dehydrogenase, or 10 μM of the antioxidant cinnamtannin B-1, reverted the effect of ethanol on total Ca2+ mobilization evoked by 1 nM CCK-8. Cinnamtannin B-1 blocked ethanol-evoked ROS production. Conclusion ethanol may lead, either directly or through ROS generation, to an over stimulation of pancreatic acinar cells in response to CCK-8, resulting in a higher Ca2+ mobilization compared to normal conditions. The actions of ethanol on CCK-8-stimulation of cells create a situation potentially leading to Ca2+ overload, which is a common pathological precursor that mediates pancreatitis.

  1. Knowledge Gaps in Rodent Pancreas Biology: Taking Human Pluripotent Stem Cell-Derived Pancreatic Beta Cells into Our Own Hands.

    Science.gov (United States)

    Santosa, Munirah Mohamad; Low, Blaise Su Jun; Pek, Nicole Min Qian; Teo, Adrian Kee Keong

    2015-01-01

    In the field of stem cell biology and diabetes, we and others seek to derive mature and functional human pancreatic β cells for disease modeling and cell replacement therapy. Traditionally, knowledge gathered from rodents is extended to human pancreas developmental biology research involving human pluripotent stem cells (hPSCs). While much has been learnt from rodent pancreas biology in the early steps toward Pdx1(+) pancreatic progenitors, much less is known about the transition toward Ngn3(+) pancreatic endocrine progenitors. Essentially, the later steps of pancreatic β cell development and maturation remain elusive to date. As a result, the most recent advances in the stem cell and diabetes field have relied upon combinatorial testing of numerous growth factors and chemical compounds in an arbitrary trial-and-error fashion to derive mature and functional human pancreatic β cells from hPSCs. Although this hit-or-miss approach appears to have made some headway in maturing human pancreatic β cells in vitro, its underlying biology is vaguely understood. Therefore, in this mini-review, we discuss some of these late-stage signaling pathways that are involved in human pancreatic β cell differentiation and highlight our current understanding of their relevance in rodent pancreas biology. Our efforts here unravel several novel signaling pathways that can be further studied to shed light on unexplored aspects of rodent pancreas biology. New investigations into these signaling pathways are expected to advance our knowledge in human pancreas developmental biology and to aid in the translation of stem cell biology in the context of diabetes treatments.

  2. The voltage-gated proton channel Hv1 is expressed in pancreatic islet β-cells and regulates insulin secretion

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Qing [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China); Che, Yongzhe [School of Medicine, Nankai University, Tianjin 300071 (China); Li, Qiang; Zhang, Shangrong [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China); Gao, Ying-Tang [Key Laboratory of Artificial Cell, Third Central Clinical College of Tianjin Medical University, Tianjin 300170 (China); Wang, Yifan; Wang, Xudong; Xi, Wang; Zuo, Weiyan [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China); Li, Shu Jie, E-mail: shujieli@nankai.edu.cn [Department of Biophysics, School of Physics Science, The Key Laboratory of Bioactive Materials, Ministry of Education, Nankai University, Tianjin 300071 (China)

    2015-12-25

    The voltage-gated proton channel Hv1 is a potent acid extruder that participates in the extrusion of the intracellular acid. Here, we showed for the first time, Hv1 is highly expressed in mouse and human pancreatic islet β-cells, as well as β-cell lines. Imaging studies demonstrated that Hv1 resides in insulin-containing granules in β-cells. Knockdown of Hv1 with RNA interference significantly reduces glucose- and K{sup +}-induced insulin secretion in isolated islets and INS-1 (832/13) β-cells and has an impairment on glucose- and K{sup +}-induced intracellular Ca{sup 2+} homeostasis. Our data demonstrated that the expression of Hv1 in pancreatic islet β-cells regulates insulin secretion through regulating Ca{sup 2+} homeostasis.

  3. β-Cell regeneration through the transdifferentiation of pancreatic cells: Pancreatic progenitor cells in the pancreas.

    Science.gov (United States)

    Kim, Hyo-Sup; Lee, Moon-Kyu

    2016-05-01

    Pancreatic progenitor cell research has been in the spotlight, as these cells have the potential to replace pancreatic β-cells for the treatment of type 1 and 2 diabetic patients with the absence or reduction of pancreatic β-cells. During the past few decades, the successful treatment of diabetes through transplantation of the whole pancreas or isolated islets has nearly been achieved. However, novel sources of pancreatic islets or insulin-producing cells are required to provide sufficient amounts of donor tissues. To overcome this limitation, the use of pancreatic progenitor cells is gaining more attention. In particular, pancreatic exocrine cells, such as duct epithelial cells and acinar cells, are attractive candidates for β-cell regeneration because of their differentiation potential and pancreatic lineage characteristics. It has been assumed that β-cell neogenesis from pancreatic progenitor cells could occur in pancreatic ducts in the postnatal stage. Several studies have shown that insulin-producing cells can arise in the duct tissue of the adult pancreas. Acinar cells also might have the potential to differentiate into insulin-producing cells. The present review summarizes recent progress in research on the transdifferentiation of pancreatic exocrine cells into insulin-producing cells, especially duct and acinar cells.

  4. Glucose activates prenyltransferases in pancreatic islet {beta}-cells

    Energy Technology Data Exchange (ETDEWEB)

    Goalstone, Marc [Department of Medicine, University of Colorado, VA Medical Center, Denver, CO 80220 (United States); Kamath, Vasudeva [Department of Pharmaceutical Sciences, Wayne State University, VA Medical Center, Detroit, MI 48201 (United States); Kowluru, Anjaneyulu, E-mail: akowluru@med.wayne.edu [Department of Pharmaceutical Sciences, Wayne State University, VA Medical Center, Detroit, MI 48201 (United States)

    2010-01-01

    A growing body of evidence implicates small G-proteins [e.g., Cdc42 and Rac1] in glucose-stimulated insulin secretion [GSIS] in the islet {beta}-cell. These signaling proteins undergo post-translational modifications [e.g., prenylation] at their C-terminal cysteine residue and appear to be essential for the transport and fusion of insulin-containing secretory granules with the plasma membrane and the exocytotic secretion of insulin. However, potential regulation of the prenylating enzymes by physiological insulin secretogues [e.g., glucose] has not been investigated thus far. Herein, we report immunological localization, sub-cellular distribution and regulation of farnesyltransferases [FTases] and geranylgeranyltransferase [GGTase] by glucose in insulin-secreting INS 832/13 {beta}-cells and normal rat islets. Our findings suggest that an insulinotropic concentration of glucose [20 mM] markedly stimulated the expression of the {alpha}-subunits of FTase/GGTase-1, but not the {beta}-subunits of FTase or GGTase-1 without significantly affecting the predominantly cytosolic distribution of these holoenzymes in INS 832/13 cells and rodent islets. Under these conditions, glucose significantly stimulated [2.5- to 4.0-fold over basal] the activities of both FTase and GGTase-1 in both cell types. Together, these findings provide the first evidence to suggest that GSIS involves activation of the endogenous islet prenyltransferases by glucose, culminating in the activation of their respective G-protein substrates, which is necessary for cytoskeletal rearrangement, vesicular transport, fusion and secretion of insulin.

  5. Pancreatic beta-cell lipotoxicity induced by overexpression of hormone-sensitive lipase

    DEFF Research Database (Denmark)

    Winzell, Maria Sörhede; Svensson, Håkan; Enerbäck, Sven

    2003-01-01

    Lipid perturbations associated with triglyceride overstorage in beta-cells impair insulin secretion, a process termed lipotoxicity. To assess the role of hormone-sensitive lipase, which is expressed and enzymatically active in beta-cells, in the development of lipotoxicity, we generated transgenic...... mice overexpressing hormone-sensitive lipase specifically in beta-cells. Transgenic mice developed glucose intolerance and severely blunted glucose-stimulated insulin secretion when challenged with a high-fat diet. As expected, both lipase activity and forskolin-stimulated lipolysis was increased...

  6. Osteocalcin protects pancreatic beta cell function and survival under high glucose conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kover, Karen, E-mail: kkover@cmh.edu [Division of Endocrine/Diabetes, Children' s Mercy Hospital & Clinics, Kansas City, MO 64108 (United States); University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108 (United States); Yan, Yun; Tong, Pei Ying; Watkins, Dara; Li, Xiaoyu [Division of Endocrine/Diabetes, Children' s Mercy Hospital & Clinics, Kansas City, MO 64108 (United States); University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108 (United States); Tasch, James; Hager, Melissa [Kansas City University Medical Biosciences, Kansas City, MO (United States); Clements, Mark; Moore, Wayne V. [Division of Endocrine/Diabetes, Children' s Mercy Hospital & Clinics, Kansas City, MO 64108 (United States); University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108 (United States)

    2015-06-19

    Diabetes is characterized by progressive beta cell dysfunction and loss due in part to oxidative stress that occurs from gluco/lipotoxicity. Treatments that directly protect beta cell function and survival in the diabetic milieu are of particular interest. A growing body of evidence suggests that osteocalcin, an abundant non-collagenous protein of bone, supports beta cell function and proliferation. Based on previous gene expression data by microarray, we hypothesized that osteocalcin protects beta cells from glucose-induced oxidative stress. To test our hypothesis we cultured isolated rat islets and INS-1E cells in the presence of normal, high, or high glucose ± osteocalcin for up to 72 h. Oxidative stress and viability/mitochondrial function were measured by H{sub 2}O{sub 2} assay and Alamar Blue assay, respectively. Caspase 3/7 activity was also measured as a marker of apoptosis. A functional test, glucose stimulated insulin release, was conducted and expression of genes/protein was measured by qRT-PCR/western blot/ELISA. Osteocalcin treatment significantly reduced high glucose-induced H{sub 2}O{sub 2} levels while maintaining viability/mitochondrial function. Osteocalcin also significantly improved glucose stimulated insulin secretion and insulin content in rat islets after 48 h of high glucose exposure compared to untreated islets. As expected sustained high glucose down-regulated gene/protein expression of INS1 and BCL2 while increasing TXNIP expression. Interestingly, osteocalcin treatment reversed the effects of high glucose on gene/protein expression. We conclude that osteocalcin can protect beta cells from the negative effects of glucose-induced oxidative stress, in part, by reducing TXNIP expression, thereby preserving beta cell function and survival. - Highlights: • Osteocalcin reduces glucose-induced oxidative stress in beta cells. • Osteocalcin preserves beta cell function and survival under stress conditions. • Osteocalcin reduces glucose

  7. Osteocalcin protects pancreatic beta cell function and survival under high glucose conditions

    International Nuclear Information System (INIS)

    Kover, Karen; Yan, Yun; Tong, Pei Ying; Watkins, Dara; Li, Xiaoyu; Tasch, James; Hager, Melissa; Clements, Mark; Moore, Wayne V.

    2015-01-01

    Diabetes is characterized by progressive beta cell dysfunction and loss due in part to oxidative stress that occurs from gluco/lipotoxicity. Treatments that directly protect beta cell function and survival in the diabetic milieu are of particular interest. A growing body of evidence suggests that osteocalcin, an abundant non-collagenous protein of bone, supports beta cell function and proliferation. Based on previous gene expression data by microarray, we hypothesized that osteocalcin protects beta cells from glucose-induced oxidative stress. To test our hypothesis we cultured isolated rat islets and INS-1E cells in the presence of normal, high, or high glucose ± osteocalcin for up to 72 h. Oxidative stress and viability/mitochondrial function were measured by H 2 O 2 assay and Alamar Blue assay, respectively. Caspase 3/7 activity was also measured as a marker of apoptosis. A functional test, glucose stimulated insulin release, was conducted and expression of genes/protein was measured by qRT-PCR/western blot/ELISA. Osteocalcin treatment significantly reduced high glucose-induced H 2 O 2 levels while maintaining viability/mitochondrial function. Osteocalcin also significantly improved glucose stimulated insulin secretion and insulin content in rat islets after 48 h of high glucose exposure compared to untreated islets. As expected sustained high glucose down-regulated gene/protein expression of INS1 and BCL2 while increasing TXNIP expression. Interestingly, osteocalcin treatment reversed the effects of high glucose on gene/protein expression. We conclude that osteocalcin can protect beta cells from the negative effects of glucose-induced oxidative stress, in part, by reducing TXNIP expression, thereby preserving beta cell function and survival. - Highlights: • Osteocalcin reduces glucose-induced oxidative stress in beta cells. • Osteocalcin preserves beta cell function and survival under stress conditions. • Osteocalcin reduces glucose-induced TXNIP

  8. Hypoglycemic and beta cell protective effects of andrographolide analogue for diabetes treatment

    Directory of Open Access Journals (Sweden)

    Larrick James W

    2009-07-01

    Full Text Available Abstract Background While all anti-diabetic agents can decrease blood glucose level directly or indirectly, few are able to protect and preserve both pancreatic beta cell mass and their insulin-secreting functions. Thus, there is an urgent need to find an agent or combination of agents that can lower blood glucose and preserve pancreatic beta cells at the same time. Herein, we report a dual-functional andrographolide-lipoic acid conjugate (AL-1. The anti-diabetic and beta cell protective activities of this novel andrographolide-lipoic acid conjugate were investigated. Methods In alloxan-treated mice (a model of type 1 diabetes, drugs were administered orally once daily for 6 days post-alloxan treatment. Fasting blood glucose and serum insulin were determined. Pathologic and immunohistochemical analysis of pancreatic islets were performed. Translocation of glucose transporter subtype 4 in soleus muscle was detected by western blot. In RIN-m cells in vitro, the effect of AL-1 on H2O2-induced damage and reactive oxidative species production stimulated by high glucose and glibenclamide were measured. Inhibition of nuclear factor kappa B (NF-κB activation induced by IL-1β and IFN-γ was investigated. Results In alloxan-induced diabetic mouse model, AL-1 lowered blood glucose, increased insulin and prevented loss of beta cells and their dysfunction, stimulated glucose transport protein subtype 4 (GLUT4 membrane translocation in soleus muscles. Pretreatment of RIN-m cells with AL-1 prevented H2O2-induced cellular damage, quenched glucose and glibenclamide-stimulated reactive oxidative species production, and inhibited cytokine-stimulated NF-κB activation. Conclusion We have demonstrated that AL-1 had both hypoglycemic and beta cell protective effects which translated into antioxidant and NF-κB inhibitory activity. AL-1 is a potential new anti-diabetic agent.

  9. Dynamics and Synchrony of Pancreatic beta-cells and Islets

    DEFF Research Database (Denmark)

    Pedersen, Morten Gram

    2006-01-01

    description of these processes and their interactions would provide important input in the search for a better treatment of the disease. The thesis describes several aspects of mathematical modeling of beta-cells relevant for the understanding of glucose stimulated insulin secretion. It consists...... and the synchronized behavior of many coupled beta-cells as well as to the synchrony of islets. Rather than developing new biophysical models, the thesis investigates existing models, their integration and simplifications, and analyzed the corresponding dynamics, in order to use these models for investigating...

  10. Intermittent Hypoxia Impairs Glucose Homeostasis in C57BL6/J Mice: Partial Improvement with Cessation of the Exposure

    Science.gov (United States)

    Polak, Jan; Shimoda, Larissa A.; Drager, Luciano F.; Undem, Clark; McHugh, Holly; Polotsky, Vsevolod Y.; Punjabi, Naresh M.

    2013-01-01

    Objectives: Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued. Interventions: C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed. Results: Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted. Conclusions: Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism. Citation: Polak J; Shimoda LA; Drager LF; Undem C; McHugh H; Polotsky VY; Punjabi NM

  11. Imaging of beta-Cell Mass and Insulitis in Insulin-Dependent (Type 1) Diabetes Mellitus

    NARCIS (Netherlands)

    Di Gialleonardo, Valentina; de Vries, Erik F. J.; Di Girolamo, Marco; Quintero, Ana M.; Dierckx, Rudi A. J. O.; Signore, Alberto

    2012-01-01

    Insulin-dependent (type 1) diabetes mellitus is a metabolic disease with a complex multifactorial etiology and a poorly understood pathogenesis. Genetic and environmental factors cause an autoimmune reaction against pancreatic beta-cells, called insulitis, confirmed in pancreatic samples obtained at

  12. Profile of blood glucose and ultrastucture of beta cells pancreatic islet in alloxan compound induced rats

    Directory of Open Access Journals (Sweden)

    I Nyoman Suarsana

    2010-06-01

    Full Text Available Diabetes is marked by elevated levels of blood glucose, and progressive changes of the structure of pancreatic islet histopathology. The objective of this research was to analyse the glucose level and histophatological feature in pancreatic islet in alloxan compound induced rats. A total of ten male Spraque Dawley rats of 2 months old were used in this study. The rats were divided into two groups: (1 negative control group (K-, and (2 positif induced alloxan group (diabetic group =DM. The rats were induced by a single dose intraperitonial injection of alloxan compound 120 mg/kg of body weight. The treatment was conducted for 28 days. Blood glucose levels of rats were analysed at 0, 4, 7, 14, 21, and 28 days following treatment. At the end of the experiment, rats were sacrificed by cervical dislocation. Pancreas was collected for analysis of histopathological study by Immunohistochemical technique, and ultrastructural study using transmission electron microscope (TEM. The result showed that Langerhans islet of diabetic rat (rat of DM group showed a marked reduction of size, number of Langerhans islet of diabetic rat decrease, and characterized by hyperglycemic condition. By using TEM, beta cells of DM group showed the rupture of mitochondrial membrane, the lost of cisternal structure of inner membrane of mitocondria, reduction of insulin secretory granules, linkage between cells acinar with free Langerhans islet, and the caryopicnotic of nucleus.

  13. Alterations in integrin expression modulates invasion of pancreatic cancer cells.

    LENUS (Irish Health Repository)

    Walsh, Naomi

    2009-01-01

    BACKGROUND: Factors mediating the invasion of pancreatic cancer cells through the extracellular matrix (ECM) are not fully understood. METHODS: In this study, sub-populations of the human pancreatic cancer cell line, MiaPaCa-2 were established which displayed differences in invasion, adhesion, anoikis, anchorage-independent growth and integrin expression. RESULTS: Clone #3 displayed higher invasion with less adhesion, while Clone #8 was less invasive with increased adhesion to ECM proteins compared to MiaPaCa-2. Clone #8 was more sensitive to anoikis than Clone #3 and MiaPaCa-2, and displayed low colony-forming efficiency in an anchorage-independent growth assay. Integrins beta 1, alpha 5 and alpha 6 were over-expressed in Clone #8. Using small interfering RNA (siRNA), integrin beta1 knockdown in Clone #8 cells increased invasion through matrigel and fibronectin, increased motility, decreased adhesion and anoikis. Integrin alpha 5 and alpha 6 knockdown also resulted in increased motility, invasion through matrigel and decreased adhesion. CONCLUSION: Our results suggest that altered expression of integrins interacting with different extracellular matrixes may play a significant role in suppressing the aggressive invasive phenotype. Analysis of these clonal populations of MiaPaCa-2 provides a model for investigations into the invasive properties of pancreatic carcinoma.

  14. [Associations of insulin resistance and pancreatic beta-cell function with plasma glucose level in type 2 diabetes].

    Science.gov (United States)

    Nian, Xiaoping; Sun, Gaisheng; Dou, Chunmei; Hou, Hongbo; Fan, Xiuping; Yu, Hongmei; Ma, Ling; He, Bingxian

    2002-06-10

    To investigate the influence of insulin resistance and pancreatic beta-cell function on plasma glucose level in type 2 diabetes so as to provide theoretical basis for reasonable selection of hypoglycemic agents. The plasma non-specific insulin (NSINS), true insulin (TI) and glucose in eight-one type 2 diabetics, 38 males and 43 females, with a mean age of 53 years, were examined 0, 30, 60 and 120 minutes after they had 75 grams of instant noodles. The patients were divided into two groups according to their fasting plasma glucose (FPG): group A (FPG = 8.89 mmol/L). The insulin resistance was evaluated by HOMA-IR, the beta-cell function was evaluated by HOMA-beta formula and the formula deltaI(30)/deltaG(30) = (deltaI(30)-deltaI(0))/(deltaG(30)-deltaG(0)). The insulin area under curve (INSAUC) was evaluated by the formula INSAUC=FINS/2+INS(30)+INS(60)+INS(120)/2. The mean FPG was 6.23 mmol/L in group A and 12.6 mmol/L in group B. PG2H was 11.7 mmol/L in group A and 19.2 mmol/L in group B. The TI levels in group B at 0, 30, 60, 120 min during standard meal test were significantly higher than those in group A: 6.15 +/- 1.06 vs 4.77 +/- 1.06, 9.76 +/- 1.1 vs 5.88 +/- 1.1,14.68 +/- 1.11 vs 6.87 +/- 1.1 and 17.13 +/- 1.12 vs 8.0 +/- 1.1 microU/dl (all P< 0.01). The NSINS showed the same trend. The insulin resistance in group B was 1.5 times that in group A. With the insulin resistance adjusted, the beta cell function in group A was 5 to 6 times that in group B. The INSAUC in group A was 1.66 times larger than that in group B, especially the INSAUC for true insulin (2 times larger). The contribution of insulin resistance and beta cell function to PG2H was half by half in group A and 1:8 in group B. beta cell function calculated by insulin (Homa-beta) explained 41% of the plasma glucose changes in group A and 54% of the plasma glucose changes in group B. The contribution of insulin deficiency to plasma glocose was 3.3.times that of insulin resistance in group A and was 9

  15. Visualizing pancreatic {beta}-cell mass with [{sup 11}C]DTBZ

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Norman Ray [Department of Radiology, Columbia University Medical School, New York, NY 10032 (United States); Souza, Fabiola [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States); Witkowski, Piotr [Department of Medicine, Columbia University Medical School, New York, NY 10032 (United States); Maffei, Antonella [Institute of Genetics and Biophysics ' Adriano Buzzati-Traverso' , CNR, Naples 80131 (Italy); Raffo, Anthony [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States); Herron, Alan [Center for Comparative Medicine and The Department of Pathology, Baylor College of Medicine, Houston, TX 77030 (United States); Kilbourn, Michael [Department of Radiology, University of Michigan, Ann Arbor, MI 48109-0638 (United States); Jurewicz, Agata [Department of Radiology, Columbia University Medical School, New York, NY 10032 (United States); Herold, Kevan [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States); Liu, Eric [Diabetes Branch, NIDDK, National Institutes of Health, Bethesda, MD 20854 (United States); Hardy, Mark Adam [Department of Medicine, Columbia University Medical School, New York, NY 10032 (United States); Van Heertum, Ronald [Department of Radiology, Columbia University Medical School, New York, NY 10032 (United States); Harris, Paul Emerson [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States)]. E-mail: peh1@columbia.edu

    2006-10-15

    {beta}-Cell mass (BCM) influences the total amount of insulin secreted, varies by individual and by the degree of insulin resistance, and is affected by physiologic and pathologic conditions. The islets of Langerhans, however, appear to have a reserve capacity of insulin secretion and, overall, assessments of insulin and blood glucose levels remain poor measures of BCM, {beta}-cell function and progression of diabetes. Thus, novel noninvasive determinations of BCM are needed to provide a quantitative endpoint for novel therapies of diabetes, islet regeneration and transplantation. Built on previous gene expression studies, we tested the hypothesis that the targeting of vesicular monoamine transporter 2 (VMAT2), which is expressed by {beta} cells, with [{sup 11}C]dihydrotetrabenazine ([{sup 11}C]DTBZ), a radioligand specific for VMAT2, and the use of positron emission tomography (PET) can provide a measure of BCM. In this report, we demonstrate decreased radioligand uptake within the pancreas of Lewis rats with streptozotocin-induced diabetes relative to their euglycemic historical controls. These studies suggest that quantitation of VMAT2 expression in {beta} cells with the use of [{sup 11}C]DTBZ and PET represents a method for noninvasive longitudinal estimates of changes in BCM that may be useful in the study and treatment of diabetes.

  16. TGF-{beta}1 increases invasiveness of SW1990 cells through Rac1/ROS/NF-{kappa}B/IL-6/MMP-2

    Energy Technology Data Exchange (ETDEWEB)

    Binker, Marcelo G. [Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8 (Canada); CBRHC Research Center, Buenos Aires (Argentina); Binker-Cosen, Andres A. [CBRHC Research Center, Buenos Aires (Argentina); Gaisano, Herbert Y. [Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8 (Canada); Cosen, Rodica H. de [CBRHC Research Center, Buenos Aires (Argentina); Cosen-Binker, Laura I., E-mail: laura.cosen.binker@utoronto.ca [Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8 (Canada); CBRHC Research Center, Buenos Aires (Argentina)

    2011-02-04

    Research highlights: {yields} Rac1 mediates TGF-{beta}1-induced SW1990 invasion through MMP-2 secretion and activation. {yields} NADPH-generated ROS act downstream of Rac1 in TGF-{beta}1-challenged SW1990 cells. {yields} TGF-{beta}1-stimulated ROS activate NF-{kappa}B in SW1990 cells. {yields} NF{kappa}B-induced IL-6 release is required for secretion and activation of MMP-2 in SW1990 cells. -- Abstract: Human pancreatic cancer invasion and metastasis have been found to correlate with increased levels of active matrix metalloproteinase 2 (MMP-2). The multifunctional cytokine transforming growth factor beta 1 (TGF-{beta}1) has been shown to increase both secretion of MMP-2 and invasion by several pancreatic cancer cell types. In the present study, we investigated the signaling pathway involved in TGF-{beta}1-promoted MMP-2 secretion and invasion by human pancreatic cancer cells SW1990. Using specific inhibitors, we found that stimulation of these tumor cells with TGF-{beta}1 induced secretion and activation of the collagenase MMP-2, which was required for TGF-{beta}1-stimulated invasion. Our results also indicate that signaling events involved in TGF-{beta}1-enhanced SW1990 invasiveness comprehend activation of Rac1 followed by generation of reactive oxygen species through nicotinamide adenine dinucleotide phosphate-oxidase, activation of nuclear factor-kappa beta, release of interleukin-6, and secretion and activation of MMP-2.

  17. [Factors causing damage and destruction of beta-cells of the islets of Langerhans in the pancreas].

    Science.gov (United States)

    Anděl, Michal; Němcová, Vlasta; Pavlíková, Nela; Urbanová, Jana; Cecháková, Marie; Havlová, Andrea; Straková, Radka; Večeřová, Livia; Mandys, Václav; Kovář, Jan; Heneberg, Petr; Trnka, Jan; Polák, Jan

    2014-09-01

    Insulin secretion in patients with manifested diabetes mellitus tends to disappear months to decades after the diagnosis, which is a clear sign of a gradual loss of pancreatic islet beta-cells. In our sample of 30 type 2 diabetic patients, whose disease manifested between 30 and 45 years of age, about a half have retained or even increased insulin secretion 30 years later, while the other half exhibit a much diminished or lost insulin secretion. Factors that can damage or destroy beta-cells can be divided into the following groups: Metabolic factors: hyperglycemia and glucotoxicity, lipotoxicity, hypoxia, reactive oxygen species; Pharmacological factors: antimicrobial medication pentamidine, SSRI antidepressants; Factors related to impaired insulin secretion: MODY type diabetes; Environmental toxic factors: rat poison Vacor, streptozotocin, polychlorinated and polybrominated hydrocarbons; Disorders of the exocrine pancreas: tumor infiltration, fibrous infiltration, chronic pancreatitis, cystic fibrosis; Infections, inflammation, autoimmunity, viral factors: Coxsackie viruses, H1N1 influenza, enteroviruses. We are currently working on finding other factors leading to beta-cell damage, studying their effect on apoptosis and necrosis and looking for possible protective factors to prevent this damage. We our increasing knowledge about the mechanisms of beta-cell damage and destruction we come ever closer to suggest measures for their prevention. In this review we offer a brief and simplified summary of some of the findings related to this area.Key words: pancreatic islet beta-cells of Langerhans - factors damaging or destroying beta-cells - insulin secretion.

  18. Intermittent hypoxia impairs glucose homeostasis in C57BL6/J mice: partial improvement with cessation of the exposure.

    Science.gov (United States)

    Polak, Jan; Shimoda, Larissa A; Drager, Luciano F; Undem, Clark; McHugh, Holly; Polotsky, Vsevolod Y; Punjabi, Naresh M

    2013-10-01

    Obstructive sleep apnea is associated with insulin resistance, glucose intolerance, and type 2 diabetes mellitus. Although several studies have suggested that intermittent hypoxia in obstructive sleep apnea may induce abnormalities in glucose homeostasis, it remains to be determined whether these abnormalities improve after discontinuation of the exposure. The objective of this study was to delineate the effects of intermittent hypoxia on glucose homeostasis, beta cell function, and liver glucose metabolism and to investigate whether the impairments improve after the hypoxic exposure is discontinued. C57BL6/J mice were exposed to 14 days of intermittent hypoxia, 14 days of intermittent air, or 7 days of intermittent hypoxia followed by 7 days of intermittent air (recovery paradigm). Glucose and insulin tolerance tests were performed to estimate whole-body insulin sensitivity and calculate measures of beta cell function. Oxidative stress in pancreatic tissue and glucose output from isolated hepatocytes were also assessed. Intermittent hypoxia increased fasting glucose levels and worsened glucose tolerance by 67% and 27%, respectively. Furthermore, intermittent hypoxia exposure was associated with impairments in insulin sensitivity and beta cell function, an increase in liver glycogen, higher hepatocyte glucose output, and an increase in oxidative stress in the pancreas. While fasting glucose levels and hepatic glucose output normalized after discontinuation of the hypoxic exposure, glucose intolerance, insulin resistance, and impairments in beta cell function persisted. Intermittent hypoxia induces insulin resistance, impairs beta cell function, enhances hepatocyte glucose output, and increases oxidative stress in the pancreas. Cessation of the hypoxic exposure does not fully reverse the observed changes in glucose metabolism.

  19. Wolfram syndrome 1 gene (WFS1) product localizes to secretory granules and determines granule acidification in pancreatic beta-cells.

    Science.gov (United States)

    Hatanaka, Masayuki; Tanabe, Katsuya; Yanai, Akie; Ohta, Yasuharu; Kondo, Manabu; Akiyama, Masaru; Shinoda, Koh; Oka, Yoshitomo; Tanizawa, Yukio

    2011-04-01

    Wolfram syndrome is an autosomal recessive disorder characterized by juvenile-onset insulin-dependent diabetes mellitus and optic atrophy. The gene responsible for the syndrome (WFS1) encodes an endoplasmic reticulum (ER) resident transmembrane protein. The Wfs1-null mouse exhibits progressive insulin deficiency causing diabetes. Previous work suggested that the function of the WFS1 protein is connected to unfolded protein response and to intracellular Ca(2+) homeostasis. However, its precise molecular function in pancreatic β-cells remains elusive. In our present study, immunofluorescent and electron-microscopic analyses revealed that WFS1 localizes not only to ER but also to secretory granules in pancreatic β-cells. Intragranular acidification was assessed by measuring intracellular fluorescence intensity raised by the acidotrophic agent, 3-[2,4-dinitroanilino]-3'-amino-N-methyldipropyramine. Compared with wild-type β-cells, there was a 32% reduction in the intensity in WFS1-deficient β-cells, indicating the impairment of granular acidification. This phenotype may, at least partly, account for the evidence that Wfs1-null islets have impaired proinsulin processing, resulting in an increased circulating proinsulin level. Morphometric analysis using electron microscopy evidenced that the density of secretory granules attached to the plasma membrane was significantly reduced in Wfs1-null β-cells relative to that in wild-type β-cells. This may be relevant to the recent finding that granular acidification is required for the priming of secretory granules preceding exocytosis and may partly explain the fact that glucose-induced insulin secretion is profoundly impaired in young prediabetic Wfs1-null mice. These results thus provide new insights into the molecular mechanisms of β-cell dysfunction in patients with Wolfram syndrome.

  20. Repeated Gene Transfection Impairs the Engraftment of Transplanted Porcine Neonatal Pancreatic Cells

    Directory of Open Access Journals (Sweden)

    Min Koo Seo

    2011-02-01

    Full Text Available BackgroundPreviously, we reported that neonatal porcine pancreatic cells transfected with hepatocyte growth factor (HGF gene in an Epstein-Barr virus (EBV-based plasmid (pEBVHGF showed improved proliferation and differentiation compared to those of the control. In this study, we examined if pancreatic cells transfected repeatedly with pEBVHGF can be successfully grafted to control blood glucose in a diabetes mouse model.MethodsNeonatal porcine pancreatic cells were cultured as a monolayer and were transfected with pEBVHGF every other day for a total of three transfections. The transfected pancreatic cells were re-aggregated and transplanted into kidney capsules of diabetic nude mice or normal nude mice. Blood glucose level and body weight were measured every other day after transplantation. The engraftment of the transplanted cells and differentiation into beta cells were assessed using immunohistochemistry.ResultsRe-aggregation of the pancreatic cells before transplantation improved engraftment of the cells and facilitated neovascularization of the graft. Right before transplantation, pancreatic cells that were transfected with pEBVHGF and then re-aggregated showed ductal cell marker expression. However, ductal cells disappeared and the cells underwent fibrosis in a diabetes mouse model two to five weeks after transplantation; these mice also did not show controlled blood glucose levels. Furthermore, pancreatic cells transplanted into nude mice with normal blood glucose showed poor graft survival regardless of the type of transfected plasmid (pCEP4, pHGF, or pEBVHGF.ConclusionFor clinical application of transfected neonatal porcine pancreatic cells, further studies are required to develop methods of overcoming the damage for the cells caused by repeated transfection and to re-aggregate them into islet-like structures.

  1. TGF-beta3 is expressed in taste buds and inhibits proliferation of primary cultured taste epithelial cells.

    Science.gov (United States)

    Nakamura, Shin-ichi; Kawai, Takayuki; Kamakura, Takashi; Ookura, Tetsuya

    2010-01-01

    Transforming growth factor-betas (TGF-betas), expressed in various tissues, play important roles in embryonic development and adult tissue homeostasis through their effects on cell proliferation, cell differentiation, cell death, and cell motility. However, expression of TGF-beta signaling components and their biological effect on taste epithelia has not been elucidated. We performed expression analysis of TGF-beta signaling components in taste epithelia and found that the TGF-beta3 mRNA was specifically expressed in taste buds. Type II TGF-betas receptor (TbetaR-II) mRNA was specifically expressed in the tongue epithelia including the taste epithelia. To elucidate the biological function of TGF-beta3 in taste epithelia, we performed proliferation assay with primary cultured taste epithelial cells. In the presence of TGF-beta3, percentage of BrdU-labeled cells decreased significantly, suggesting that the TGF-beta3 inhibited the proliferation of cultured taste epithelial cells through inhibiting cell-cycle entry into S phase. By quantitative reverse transcription-polymerase chain reaction assay, we found that the TGF-beta3 resulted in an increased level of expression of p15Ink4b and p21Cip1, suggesting that the TGF-beta3 inhibited the taste epithelial cell proliferation through inhibiting G1cyclin-Cdk complexes. Taken together, these results suggested that the TGF-beta3 may regulate taste epithelial cell homeostasis through controlling cell proliferation.

  2. Calcium has a permissive role in interleukin-1beta-induced c-jun N-terminal kinase activation in insulin-secreting cells

    DEFF Research Database (Denmark)

    Størling, Joachim; Zaitsev, Sergei V; Kapelioukh, Iouri L

    2005-01-01

    The c-jun N-terminal kinase (JNK) signaling pathway mediates IL-1beta-induced apoptosis in insulin-secreting cells, a mechanism relevant to the destruction of pancreatic beta-cells in type 1 and 2 diabetes. However, the mechanisms that contribute to IL-1beta activation of JNK in beta-cells are la...

  3. Response gene to complement-32 enhances metastatic phenotype by mediating transforming growth factor beta-induced epithelial-mesenchymal transition in human pancreatic cancer cell line BxPC-3

    Directory of Open Access Journals (Sweden)

    Zhu Liang

    2012-03-01

    Full Text Available Abstract Background Response gene to complement-32 (RGC-32 is comprehensively expressed in many kinds of tissues and has been reported to be expressed abnormally in different kinds of human tumors. However, the role of RGC-32 in cancer remains controversial and no reports have described the effect of RGC-32 in pancreatic cancer. The present study investigated the expression of RGC-32 in pancreatic cancer tissues and explored the role of RGC-32 in transforming growth factor-beta (TGF-β-induced epithelial-mesenchymal transition (EMT in human pancreatic cancer cell line BxPC-3. Methods Immunohistochemical staining of RGC-32 and E-cadherin was performed on specimens from 42 patients with pancreatic cancer, 12 with chronic pancreatitis and 8 with normal pancreas. To evaluate the role of RGC-32 in TGF-β-induced EMT in pancreatic cancer cells, BxPC-3 cells were treated with TGF-β1, and RGC-32 siRNA silencing and gene overexpression were performed as well. The mRNA expression and protein expression of RGC-32 and EMT markers such E-cadherin and vimentin were determined by quantitative reverse transcription-PCR (qRT-PCR and western blot respectively. Finally, migration ability of BxPC-3 cells treated with TGF-β and RGC-32 siRNA transfection was examined by transwell cell migration assay. Results We found stronger expression of RGC-32 and higher abnormal expression rate of E-cadherin in pancreatic cancer tissues than those in chronic pancreatitis tissues and normal pancreatic tissues. Immunohistochemical analysis revealed that both RGC-32 positive expression and E-cadherin abnormal expression in pancreatic cancer were correlated with lymph node metastasis and TNM staging. In addition, a significant and positive correlation was found between positive expression of RGC-32 and abnormal expression of E-cadherin. Furthermore, in vitro, we found sustained TGF-β stimuli induced EMT and up-regulated RGC-32 expression in BxPC-3 cells. By means of si

  4. Towards consistent generation of pancreatic lineage progenitors from human pluripotent stem cells.

    Science.gov (United States)

    Rostovskaya, Maria; Bredenkamp, Nicholas; Smith, Austin

    2015-10-19

    Human pluripotent stem cells can in principle be used as a source of any differentiated cell type for disease modelling, drug screening, toxicology testing or cell replacement therapy. Type I diabetes is considered a major target for stem cell applications due to the shortage of primary human beta cells. Several protocols have been reported for generating pancreatic progenitors by in vitro differentiation of human pluripotent stem cells. Here we first assessed one of these protocols on a panel of pluripotent stem cell lines for capacity to engender glucose sensitive insulin-producing cells after engraftment in immunocompromised mice. We observed variable outcomes with only one cell line showing a low level of glucose response. We, therefore, undertook a systematic comparison of different methods for inducing definitive endoderm and subsequently pancreatic differentiation. Of several protocols tested, we identified a combined approach that robustly generated pancreatic progenitors in vitro from both embryo-derived and induced pluripotent stem cells. These findings suggest that, although there are intrinsic differences in lineage specification propensity between pluripotent stem cell lines, optimal differentiation procedures may consistently direct a substantial fraction of cells into pancreatic specification. © 2015 The Authors.

  5. A post-translational balancing act: the good and the bad of SUMOylation in pancreatic islets.

    Science.gov (United States)

    MacDonald, Patrick E

    2018-04-01

    Post-translational modification of proteins contributes to the control of cell function and survival. The balance of these in insulin-producing pancreatic beta cells is important for the maintenance of glucose homeostasis. Protection from the damaging effects of reactive oxygen species is required for beta cell survival, but if this happens at the expense of insulin secretory function then the ability of islets to respond to changing metabolic conditions may be compromised. In this issue of Diabetologia, He et al ( https://doi.org/10.1007/s00125-017-4523-9 ) show that post-translational attachment of small ubiquitin-like modifier (SUMO) to target lysine residues (SUMOylation) strikes an important balance between the protection of beta cells from oxidative stress and the maintenance of insulin secretory function. They show that SUMOylation is required to stabilise nuclear factor erythroid 2-related factor 2 (NRF2) and increase antioxidant gene expression. Decreasing SUMOylation in beta cells impairs their antioxidant capacity, causes cell death, hyperglycaemia, and increased sensitivity to streptozotocin-induced diabetes, while increasing SUMOylation is protective. However, this protection from overt diabetes occurs in concert with glucose intolerance due to impaired beta cell function. A possible role for SUMOylation as a key factor balancing beta cell protection vs beta cell responsiveness to metabolic cues is discussed in this Commentary.

  6. Alkali pH directly activates ATP-sensitive K+ channels and inhibits insulin secretion in beta-cells.

    Science.gov (United States)

    Manning Fox, Jocelyn E; Karaman, Gunce; Wheeler, Michael B

    2006-11-17

    Glucose stimulation of pancreatic beta-cells is reported to lead to sustained alkalization, while extracellular application of weak bases is reported to inhibit electrical activity and decrease insulin secretion. We hypothesize that beta-cell K(ATP) channel activity is modulated by alkaline pH. Using the excised patch-clamp technique, we demonstrate a direct stimulatory action of alkali pH on recombinant SUR1/Kir6.2 channels due to increased open probability. Bath application of alkali pH similarly activates native islet beta-cell K(ATP) channels, leading to an inhibition of action potentials, and hyperpolarization of membrane potential. In situ pancreatic perfusion confirms that these cellular effects of alkali pH are observable at a functional level, resulting in decreases in both phase 1 and phase 2 glucose-stimulated insulin secretion. Our data are the first to report a stimulatory effect of a range of alkali pH on K(ATP) channel activity and link this to downstream effects on islet beta-cell function.

  7. Basal metabolic state governs AIF-dependent growth support in pancreatic cancer cells

    International Nuclear Information System (INIS)

    Scott, Andrew J.; Wilkinson, Amanda S.; Wilkinson, John C.

    2016-01-01

    Apoptosis-inducing factor (AIF), named for its involvement in cell death pathways, is a mitochondrial protein that regulates metabolic homeostasis. In addition to supporting the survival of healthy cells, AIF also plays a contributory role to the development of cancer through its enzymatic activity, and we have previously shown that AIF preferentially supports advanced-stage prostate cancer cells. Here we further evaluated the role of AIF in tumorigenesis by exploring its function in pancreatic cancer, a disease setting that most often presents at an advanced stage by the time of diagnosis. A bioinformatics approach was first employed to investigate AIF mRNA transcript levels in pancreatic tumor specimens vs. normal tissues. AIF-deficient pancreatic cancer cell lines were then established via lentiviral infection. Immunoblot analysis was used to determine relative protein quantities within cells. Cell viability was measured by flow cytometry; in vitro and Matrigel™ growth/survival using Coulter™ counting and phase contrast microscopy; and glucose consumption in the absence and presence of Matrigel™ using spectrophotometric methods. Archival gene expression data revealed a modest elevation of AIF transcript levels in subsets of pancreatic tumor specimens, suggesting a possible role in disease progression. AIF expression was then suppressed in a panel of five pancreatic cancer cell lines that display diverse metabolic phenotypes. AIF ablation selectively crippled the growth of cells in vitro in a manner that directly correlated with the loss of mitochondrial respiratory chain subunits and altered glucose metabolism, and these effects were exacerbated in the presence of Matrigel™ substrate. This suggests a critical metabolic role for AIF to pancreatic tumorigenesis, while the spectrum of sensitivities to AIF ablation depends on basal cellular metabolic phenotypes. Altogether these data indicate that AIF supports the growth and survival of metabolically defined

  8. Endocrine and exocrine pancreatic insufficiency after acute pancreatitis: long-term follow-up study.

    Science.gov (United States)

    Tu, Jianfeng; Zhang, Jingzhu; Ke, Lu; Yang, Yue; Yang, Qi; Lu, Guotao; Li, Baiqiang; Tong, Zhihui; Li, Weiqin; Li, Jieshou

    2017-10-27

    Patients could develop endocrine and exocrine pancreatic insufficiency after acute pancreatitis (AP), but the morbidity, risk factors and outcome remain unclear. The aim of the present study was to evaluate the incidence of endocrine and exocrine pancreatic insufficiency after AP and the risk factors of endocrine pancreatic insufficiency through a long-term follow-up investigation. Follow-up assessment of the endocrine and exocrine function was conducted for the discharged patients with AP episodes. Oral Glucose Tolerance Test (OGTT) and faecal elastase-1(FE-1) test were used as primary parameters. Fasting blood-glucose (FBG), fasting insulin (FINS), glycosylated hemoglobin HBA1c, 2-h postprandial blood glucose (2hPG), Homa beta cell function index (HOMA-β), homeostasis model assessment of insulin resistance (HOMA-IR) and FE-1 were collected. Abdominal contrast-enhanced computed tomography (CECT) was performed to investigate the pancreatic morphology and the other related data during hospitalization was also collected. One hundred thirteen patients were included in this study and 34 of whom (30.1%) developed diabetes mellitus (DM), 33 (29.2%) suffered impaired glucose tolerance (IGT). Moreover, 33 patients (29.2%) developed mild to moderate exocrine pancreatic insufficiency with 100μg/gpancreatic insufficiency with FE-1pancreatic necrosis was significant higher than that in the non-pancreatic necrosis group (X 2  = 13.442,P = 0.001). The multiple logistic regression analysis showed that extent of pancreatic necrosisendocrine pancreatic insufficiency. HOMA-IR (P = 0.002, OR = 6.626), Wall-off necrosis (WON) (P = 0.013, OR = 184.772) were the risk factors. The integrated morbidity of DM and IGT after AP was 59.25%, which was higher than exocrine pancreatic insufficiency. 6.2% and 29.2% of patients developed severe and mild to moderate exocrine pancreatic insufficiency, respectively. The extent of pancreatic necrosis>50%, WON and insulin resistance were

  9. Suppressor of cytokine signalling (SOCS)-3 protects beta cells against IL-1beta-mediated toxicity through inhibition of multiple nuclear factor-kappaB-regulated proapoptotic pathways

    DEFF Research Database (Denmark)

    Karlsen, Allan Ertman; Heding, P E; Frobøse, H

    2004-01-01

    The proinflammatory cytokine IL-1beta induces apoptosis in pancreatic beta cells via pathways dependent on nuclear factor-kappaB (NF-kappaB), mitogen-activated protein kinase, and protein kinase C. We recently showed suppressor of cytokine signalling (SOCS)-3 to be a natural negative feedback reg...... regulator of IL-1beta- and IFN-gamma-mediated signalling in rat islets and beta cell lines, preventing their deleterious effects. However, the mechanisms underlying SOCS-3 inhibition of IL-1beta signalling and prevention against apoptosis remain unknown....

  10. Distinct changes in pulmonary surfactant homeostasis in common beta-chain-and GM-CSF-deficient mice

    NARCIS (Netherlands)

    Reed, JA; Ikegami, M; Robb, L; Begley, CG; Ross, G; Whitsett, JA

    Pulmonary alveolar proteinosis (PAP) is caused by inactivation of either granulocyte-macrophage colony-stimulating factor (GMCSF) or GM receptor common beta-chain (beta(c)) genes in mice [GM(-/-), beta(c)(-/-)], demonstrating a critical role of GM-CSF signaling in surfactant homeostasis. To

  11. Reprogramming of various cell types to a beta-like state by Pdx1, Ngn3 and MafA.

    Directory of Open Access Journals (Sweden)

    Ersin Akinci

    Full Text Available The three transcription factors, PDX1, NGN3 and MAFA, are very important in pancreatic development. Overexpression of these three factors can reprogram both pancreatic exocrine cells and SOX9-positive cells of the liver into cells resembling pancreatic beta cells. In this study we investigate whether other cell types can be reprogrammed. Eight cell types are compared and the results are consistent with the idea that reprogramming occurs to a greater degree for developmentally related cells (pancreas, liver than for other types, such as fibroblasts. Using a line of mouse hepatocyte-derived cells we screened 13 compounds for the ability to increase the yield of reprogrammed cells. Three are active and when used in combination they can increase the yield of insulin-immunopositive cells by a factor of six. These results should contribute to the eventual ability to develop a new cure for diabetes based on the ability to reprogram other cells in the body to a beta cell phenotype.

  12. PDX1, Neurogenin-3, and MAFA: critical transcription regulators for beta cell development and regeneration

    Directory of Open Access Journals (Sweden)

    Yaxi Zhu

    2017-11-01

    Full Text Available Abstract Transcription factors regulate gene expression through binding to specific enhancer sequences. Pancreas/duodenum homeobox protein 1 (PDX1, Neurogenin-3 (NEUROG3, and V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MAFA are transcription factors critical for beta cell development and maturation. NEUROG3 is expressed in endocrine progenitor cells and controls islet differentiation and regeneration. PDX1 is essential for the development of pancreatic exocrine and endocrine cells including beta cells. PDX1 also binds to the regulatory elements and increases insulin gene transcription. Likewise, MAFA binds to the enhancer/promoter region of the insulin gene and drives insulin expression in response to glucose. In addition to those natural roles in beta cell development and maturation, ectopic expression of PDX1, NEUROG3, and/or MAFA has been successfully used to reprogram various cell types into insulin-producing cells in vitro and in vivo, such as pancreatic exocrine cells, hepatocytes, and pluripotent stem cells. Here, we review biological properties of PDX1, NEUROG3, and MAFA, and their applications and limitations for beta cell regenerative approaches. The primary source literature for this review was acquired using a PubMed search for articles published between 1990 and 2017. Search terms include diabetes, insulin, trans-differentiation, stem cells, and regenerative medicine.

  13. Can pancreatic duct-derived progenitors be a source of islet regeneration?

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Bing [Department of Endocrinology, First Hospital of Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China); Zhan, Xiao-Rong, E-mail: xiaorongzhan@sina.com [Department of Endocrinology, First Hospital of Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China); Yi, Ran [Department of Endocrinology, First Hospital of Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China); Yang, Baofeng [Department of Pharmacology, State Key Laboratory of Biomedicine and Pharmacology, Harbin Medical University, Harbin, Hei Long Jiang Province 150001 (China)

    2009-06-12

    The regenerative process of the pancreas is of interest because the main pathogenesis of diabetes mellitus is an inadequate number of insulin-producing {beta}-cells. The functional mass of {beta}-cells is decreased in type 1 diabetes, so replacing missing {beta}-cells or triggering their regeneration may allow for improved type 1 diabetes treatment. Therefore, expansion of the {beta}-cell mass from endogenous sources, either in vivo or in vitro, represents an area of increasing interest. The mechanism of islet regeneration remains poorly understood, but the identification of islet progenitor sources is critical for understanding {beta}-cell regeneration. One potential source is the islet proper, via the dedifferentiation, proliferation, and redifferentiation of facultative progenitors residing within the islet. Neogenesis, or that the new pancreatic islets can derive from progenitor cells present within the ducts has been reported, but the existence and identity of the progenitor cells have been debated. In this review, we focus on pancreatic ductal cells, which are islet progenitors capable of differentiating into islet {beta}-cells. Islet neogenesis, seen as budding of hormone-positive cells from the ductal epithelium, is considered to be one mechanism for normal islet growth after birth and in regeneration, and has suggested the presence of pancreatic stem cells. Numerous results support the neogenesis hypothesis, the evidence for the hypothesis in the adult comes primarily from morphological studies that have in common the production of damage to all or part of the pancreas, with consequent inflammation and repair. Although numerous studies support a ductal origin for new islets after birth, lineage-tracing experiments are considered the 'gold standard' of proof. Lineage-tracing experiments show that pancreatic duct cells act as progenitors, giving rise to new islets after birth and after injury. The identification of differentiated pancreatic ductal

  14. Foodborne cereulide causes beta-cell dysfunction and apoptosis.

    Directory of Open Access Journals (Sweden)

    Roman Vangoitsenhoven

    Full Text Available To study the effects of cereulide, a food toxin often found at low concentrations in take-away meals, on beta-cell survival and function.Cell death was quantified by Hoechst/Propidium Iodide in mouse (MIN6 and rat (INS-1E beta-cell lines, whole mouse islets and control cell lines (HepG2 and COS-1. Beta-cell function was studied by glucose-stimulated insulin secretion (GSIS. Mechanisms of toxicity were evaluated in MIN6 cells by mRNA profiling, electron microscopy and mitochondrial function tests.24 h exposure to 5 ng/ml cereulide rendered almost all MIN6, INS-1E and pancreatic islets apoptotic, whereas cell death did not increase in the control cell lines. In MIN6 cells and murine islets, GSIS capacity was lost following 24 h exposure to 0.5 ng/ml cereulide (P<0.05. Cereulide exposure induced markers of mitochondrial stress including Puma (p53 up-regulated modulator of apoptosis, P<0.05 and general pro-apoptotic signals as Chop (CCAAT/-enhancer-binding protein homologous protein. Mitochondria appeared swollen upon transmission electron microscopy, basal respiration rate was reduced by 52% (P<0.05 and reactive oxygen species increased by more than twofold (P<0.05 following 24 h exposure to 0.25 and 0.50 ng/ml cereulide, respectively.Cereulide causes apoptotic beta-cell death at low concentrations and impairs beta-cell function at even lower concentrations, with mitochondrial dysfunction underlying these defects. Thus, exposure to cereulide even at concentrations too low to cause systemic effects appears deleterious to the beta-cell.

  15. GTP- and GDP-Dependent Rab27a Effectors in Pancreatic Beta-Cells.

    Science.gov (United States)

    Yamaoka, Mami; Ishizaki, Toshimasa; Kimura, Toshihide

    2015-01-01

    Small guanosine triphosphatases (GTPases) participate in a wide variety of cellular functions including proliferation, differentiation, adhesion, and intracellular transport. Conventionally, only the guanosine 5'-triphosphate (GTP)-bound small GTPase interacts with effector proteins, and the resulting downstream signals control specific cellular functions. Therefore, the GTP-bound form is regarded as active, and the focus has been on searching for proteins that bind the GTP form to look for their effectors. The Rab family small GTPase Rab27a is highly expressed in some secretory cells and is involved in the control of membrane traffic. The present study reviews recent progress in our understanding of the roles of Rab27a and its effectors in pancreatic beta-cells. In the basal state, GTP-bound Rab27a controls insulin secretion at pre-exocytic stages via its GTP-dependent effectors. We previously identified novel guanosine 5'-diphosphate (GDP)-bound Rab27-interacting proteins. Interestingly, GDP-bound Rab27a controls endocytosis of the secretory membrane via its interaction with these proteins. We also demonstrated that the insulin secretagogue glucose converts Rab27a from its GTP- to GDP-bound forms. Thus, GTP- and GDP-bound Rab27a regulate pre-exocytic and endocytic stages in membrane traffic, respectively. Since the physiological importance of GDP-bound GTPases has been largely overlooked, we consider that the investigation of GDP-dependent effectors for other GTPases is necessary for further understanding of cellular function.

  16. Implications for the offspring of circulating factors involved in beta cell adaptation in pregnancy

    DEFF Research Database (Denmark)

    Nalla, Amarnadh; Ringholm, Lene; Søstrup, Birgitte

    2014-01-01

    is able to stimulate proliferation of rat beta cells. We have identified several circulating factors that may contribute to beta cell adaptation to pregnancy. Further studies are needed to elucidate their possible role in glucose homeostasis in the mother and her offspring.......OBJECTIVE: Several studies have shown an increase in beta cell mass during pregnancy. Somatolactogenic hormones are known to stimulate the proliferation of existing beta cells in rodents whereas the mechanism in humans is still unclear. We hypothesize that in addition to somatolactogenic hormones...... there are other circulating factors involved in beta cell adaptation to pregnancy. This study aimed at screening for potential pregnancy-associated circulating beta cell growth factors. SAMPLES: Serum samples from nonpregnant and pregnant women. METHODS: The effect of serum from pregnant women...

  17. Paracrine GABA and insulin regulate pancreatic alpha cell proliferation in a mouse model of type 1 diabetes.

    Science.gov (United States)

    Feng, Allen L; Xiang, Yun-Yan; Gui, Le; Kaltsidis, Gesthika; Feng, Qingping; Lu, Wei-Yang

    2017-06-01

    This study aimed to elucidate the mechanism of increased proliferation of alpha cells in recent-onset type 1 diabetes. Pancreatic beta cells express GAD and produce γ-aminobutyric acid (GABA), which inhibits alpha cell secretion of glucagon. We explored the roles of GABA in alpha cell proliferation in conditions corresponding to type 1 diabetes in a mouse model and in vitro. Type 1 diabetes was induced by injecting the mice with streptozotocin (STZ). Some of the STZ-injected mice were treated with GABA (10 mg/kg daily) for 12 days. Isolated pancreatic islets were treated with STZ or STZ together with GABA for 2 days. The effects of GABA treatment on STZ-induced alpha cell proliferation in vivo and in vitro were assessed. The effect of muscimol, a GABA receptor agonist, on αTC1-6 cell proliferation was also examined. STZ injection substantially decreased levels of GAD, GABA and insulin in pancreatic beta cells 12 h after injection; this was followed by an upsurge of phosphorylated mechanistic target of rapamycin (p-mTOR) in the alpha cells at day 1, and a significant increase in alpha cell mass at day 3. Treating STZ-injected mice with GABA largely restored the immunodetectable levels of insulin and GAD in the beta cells and significantly decreased the number of aldehyde dehydrogenase 1 family, member A3 (ALDH1a3)-positive cells, alpha cell mass and hyperglucagonaemia. STZ treatment also increased alpha cell proliferation in isolated islets, which was reversed by co-treatment with GABA. Muscimol, together with insulin, significantly lowered the level of cytosolic Ca 2+ and p-mTOR, and decreased the proliferation rate of αTC1-6 cells. GABA signalling critically controls the alpha cell population in pancreatic islets. Low intraislet GABA may contribute to alpha cell hyperplasia in early type 1 diabetes.

  18. Antibody Response to Serpin B13 Induces Adaptive Changes in Mouse Pancreatic Islets and Slows Down the Decline in the Residual Beta Cell Function in Children with Recent Onset of Type 1 Diabetes Mellitus.

    Science.gov (United States)

    Kryvalap, Yury; Lo, Chi-Wen; Manuylova, Ekaterina; Baldzizhar, Raman; Jospe, Nicholas; Czyzyk, Jan

    2016-01-01

    Type 1 diabetes mellitus (T1D) is characterized by a heightened antibody (Ab) response to pancreatic islet self-antigens, which is a biomarker of progressive islet pathology. We recently identified a novel antibody to clade B serpin that reduces islet-associated T cell accumulation and is linked to the delayed onset of T1D. As natural immunity to clade B arises early in life, we hypothesized that it may influence islet development during that time. To test this possibility healthy young Balb/c male mice were injected with serpin B13 mAb or IgG control and examined for the number and cellularity of pancreatic islets by immunofluorescence and FACS. Beta cell proliferation was assessed by measuring nucleotide analog 5-ethynyl-2'-deoxyuridine (5-EdU) incorporation into the DNA and islet Reg gene expression was measured by real time PCR. Human studies involved measuring anti-serpin B13 autoantibodies by Luminex. We found that injecting anti-serpin B13 monoclonal Ab enhanced beta cell proliferation and Reg gene expression, induced the generation of ∼80 pancreatic islets per animal, and ultimately led to increase in the beta cell mass. These findings are relevant to human T1D because our analysis of subjects just diagnosed with T1D revealed an association between baseline anti-serpin activity and slower residual beta cell function decline in the first year after the onset of diabetes. Our findings reveal a new role for the anti-serpin immunological response in promoting adaptive changes in the endocrine pancreas and suggests that enhancement of this response could potentially help impede the progression of T1D in humans. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Lysosome associated membrane proteins maintain pancreatic acinar cell homeostasis : LAMP-2 deficient mice develop pancreatitis

    NARCIS (Netherlands)

    Mareninova, Olga A; Sendler, Matthias; Malla, Sudarshan Ravi; Yakubov, Iskandar; French, Samuel W; Tokhtaeva, Elmira; Vagin, Olga; Oorschot, Viola; Lüllmann-Rauch, Renate; Blanz, Judith; Dawson, David; Klumperman, Judith; Lerch, Markus M; Mayerle, Julia; Gukovsky, Ilya; Gukovskaya, Anna S

    2015-01-01

    BACKGROUND & AIMS: The pathogenic mechanism of pancreatitis is poorly understood. Recent evidence implicates defective autophagy in pancreatitis responses; however, the pathways mediating impaired autophagy in pancreas remain largely unknown. Here, we investigate the role of lysosome associated

  20. Co-culture of neural crest stem cells (NCSC and insulin producing beta-TC6 cells results in cadherin junctions and protection against cytokine-induced beta-cell death.

    Directory of Open Access Journals (Sweden)

    Anongnad Ngamjariyawat

    Full Text Available PURPOSE: Transplantation of pancreatic islets to Type 1 diabetes patients is hampered by inflammatory reactions at the transplantation site leading to dysfunction and death of insulin producing beta-cells. Recently we have shown that co-transplantation of neural crest stem cells (NCSCs together with the islet cells improves transplantation outcome. The aim of the present investigation was to describe in vitro interactions between NCSCs and insulin producing beta-TC6 cells that may mediate protection against cytokine-induced beta-cell death. PROCEDURES: Beta-TC6 and NCSC cells were cultured either alone or together, and either with or without cell culture inserts. The cultures were then exposed to the pro-inflammatory cytokines IL-1β and IFN-γ for 48 hours followed by analysis of cell death rates (flow cytometry, nitrite production (Griess reagent, protein localization (immunofluorescence and protein phosphorylation (flow cytometry. RESULTS: We observed that beta-TC6 cells co-cultured with NCSCs were protected against cytokine-induced cell death, but not when separated by cell culture inserts. This occurred in parallel with (i augmented production of nitrite from beta-TC6 cells, indicating that increased cell survival allows a sustained production of nitric oxide; (ii NCSC-derived laminin production; (iii decreased phospho-FAK staining in beta-TC6 cell focal adhesions, and (iv decreased beta-TC6 cell phosphorylation of ERK(T202/Y204, FAK(Y397 and FAK(Y576. Furthermore, co-culture also resulted in cadherin and beta-catenin accumulations at the NCSC/beta-TC6 cell junctions. Finally, the gap junction inhibitor carbenoxolone did not affect cytokine-induced beta-cell death during co-culture with NCSCs. CONCLUSION: In summary, direct contacts, but not soluble factors, promote improved beta-TC6 viability when co-cultured with NCSCs. We hypothesize that cadherin junctions between NCSC and beta-TC6 cells promote powerful signals that maintain beta-cell

  1. Rewiring carbohydrate catabolism differentially affects survival of pancreatic cancer cell lines with diverse metabolic profiles

    Science.gov (United States)

    Tataranni, Tiziana; Agriesti, Francesca; Ruggieri, Vitalba; Mazzoccoli, Carmela; Simeon, Vittorio; Laurenzana, Ilaria; Scrima, Rosella; Pazienza, Valerio; Capitanio, Nazzareno; Piccoli, Claudia

    2017-01-01

    An increasing body of evidence suggests that targeting cellular metabolism represents a promising effective approach to treat pancreatic cancer, overcome chemoresistance and ameliorate patient's prognosis and survival. In this study, following whole-genome expression analysis, we selected two pancreatic cancer cell lines, PANC-1 and BXPC-3, hallmarked by distinct metabolic profiles with specific concern to carbohydrate metabolism. Functional comparative analysis showed that BXPC-3 displayed a marked deficit of the mitochondrial respiratory and oxidative phosphorylation activity and a higher production of reactive oxygen species and a reduced NAD+/NADH ratio, indicating their bioenergetic reliance on glycolysis and a different redox homeostasis as compared to PANC-1. Both cell lines were challenged to rewire their metabolism by substituting glucose with galactose as carbon source, a condition inhibiting the glycolytic flux and fostering full oxidation of the sugar carbons. The obtained data strikingly show that the mitochondrial respiration-impaired-BXPC-3 cell line was unable to sustain the metabolic adaptation required by glucose deprivation/substitution, thereby resulting in a G2\\M cell cycle shift, unbalance of the redox homeostasis, apoptosis induction. Conversely, the mitochondrial respiration-competent-PANC-1 cell line did not show clear evidence of cell sufferance. Our findings provide a strong rationale to candidate metabolism as a promising target for cancer therapy. Defining the metabolic features at time of pancreatic cancer diagnosis and likely of other tumors, appears to be crucial to predict the responsiveness to therapeutic approaches or coadjuvant interventions affecting metabolism. PMID:28476035

  2. Diabetes mellitus in Tropical Chronic Pancreatitis Is Not Just a Secondary Type of Diabetes

    OpenAIRE

    Rossi, L.; Parvin, S.; Hassan, Z.; Hildebrand, P.; Keller, U.; Ali, L.; Beglinger, C.; Azad Khan, A. K.; Whitcomb, David C.; Gyr, N.

    2004-01-01

    AIMS: In chronic calcific pancreatitis of the tropics, etiology and relationship to developing diabetes mellitus are unknown. Some consider these cases a straightforward secondary type of diabetes, while others suggest selective beta-cell impairment. Testing pancreatic function, we investigated whether selective beta-cell impairment triggers diabetes associated with tropical pancreatitis. METHODS: At a Bangladeshi research institute, 8 chronic tropical pancreatitis and no diabetes mellitus su...

  3. The enteroinsular axis and endocrine pancreatic function in chronic alcohol consumers: evidence for early beta-cell hypofunction.

    Science.gov (United States)

    Patto, R J; Russo, E K; Borges, D R; Neves, M M

    1993-09-01

    Chronic alcohol consumers may have, as judged by functional criteria, exocrine as well as endocrine pancreatic dysfunction, the latter represented by a decreased insulin response to an oral glucose load. To investigate whether this decreased insulin response was due to an ethanol-induced beta-cell dysfunction or to an ethanol-induced dysfunction of the enteroinsular axis, we determined glucose, insulin, and C-peptide plasma concentrations following an oral and an intravenous glucose load in 16 healthy volunteer nonalcohol consumers and in 10 chronic alcohol consumers. In each group, total integrated response for glucose did not significantly change whether glucose was given orally or intravenously, indicating isoglycemic glucose loads. The total integrated response values for insulin in the alcoholic group following both glucose loads as well as C-peptide plasma concentrations were significantly lower than in the control group. Moreover, in both groups the insulin TIR values following the oral glucose load were significantly greater than the values obtained following the intravenous glucose load, indicating an incretin effect. These results indicate that the decreased insulin response observed in alcoholics was not caused by a dysfunction of the enteroinsular axis because it also occurred following an intravenous glucose load, but by an ethanol-induced beta-cell dysfunction because C-peptide and insulin were proportionally decreased in this group.

  4. Small amounts of tissue preserve pancreatic function: Long-term follow-up study of middle-segment preserving pancreatectomy.

    Science.gov (United States)

    Lu, Zipeng; Yin, Jie; Wei, Jishu; Dai, Cuncai; Wu, Junli; Gao, Wentao; Xu, Qing; Dai, Hao; Li, Qiang; Guo, Feng; Chen, Jianmin; Xi, Chunhua; Wu, Pengfei; Zhang, Kai; Jiang, Kuirong; Miao, Yi

    2016-11-01

    Middle-segment preserving pancreatectomy (MPP) is a novel procedure for treating multifocal lesions of the pancreas while preserving pancreatic function. However, long-term pancreatic function after this procedure remains unclear.The aims of this current study are to investigate short- and long-term outcomes, especially long-term pancreatic endocrine function, after MPP.From September 2011 to December 2015, 7 patients underwent MPP in our institution, and 5 cases with long-term outcomes were further analyzed in a retrospective manner. Percentage of tissue preservation was calculated using computed tomography volumetry. Serum insulin and C-peptide levels after oral glucose challenge were evaluated in 5 patients. Beta-cell secreting function including modified homeostasis model assessment of beta-cell function (HOMA2-beta), area under the curve (AUC) for C-peptide, and C-peptide index were evaluated and compared with those after pancreaticoduodenectomy (PD) and total pancreatectomy. Exocrine function was assessed based on questionnaires.Our case series included 3 women and 2 men, with median age of 50 (37-81) years. Four patients underwent pylorus-preserving PD together with distal pancreatectomy (DP), including 1 with spleen preserved. The remaining patient underwent Beger procedure and spleen-preserving DP. Median operation time and estimated intraoperative blood loss were 330 (250-615) min and 800 (400-5500) mL, respectively. Histological examination revealed 3 cases of metastatic lesion to the pancreas, 1 case of chronic pancreatitis, and 1 neuroendocrine tumor. Major postoperative complications included 3 cases of delayed gastric emptying and 2 cases of postoperative pancreatic fistula. Imaging studies showed that segments representing 18.2% to 39.5% of the pancreas with good blood supply had been preserved. With a median 35.0 months of follow-ups on pancreatic functions, only 1 patient developed new-onset diabetes mellitus of the 4 preoperatively euglycemic

  5. Role of MicroRNAs in Islet Beta-Cell Compensation and Failure during Diabetes

    Directory of Open Access Journals (Sweden)

    Valérie Plaisance

    2014-01-01

    Full Text Available Pancreatic beta-cell function and mass are markedly adaptive to compensate for the changes in insulin requirement observed during several situations such as pregnancy, obesity, glucocorticoids excess, or administration. This requires a beta-cell compensation which is achieved through a gain of beta-cell mass and function. Elucidating the physiological mechanisms that promote functional beta-cell mass expansion and that protect cells against death, is a key therapeutic target for diabetes. In this respect, several recent studies have emphasized the instrumental role of microRNAs in the control of beta-cell function. MicroRNAs are negative regulators of gene expression, and are pivotal for the control of beta-cell proliferation, function, and survival. On the one hand, changes in specific microRNA levels have been associated with beta-cell compensation and are triggered by hormones or bioactive peptides that promote beta-cell survival and function. Conversely, modifications in the expression of other specific microRNAs contribute to beta-cell dysfunction and death elicited by diabetogenic factors including, cytokines, chronic hyperlipidemia, hyperglycemia, and oxidized LDL. This review underlines the importance of targeting the microRNA network for future innovative therapies aiming at preventing the beta-cell decline in diabetes.

  6. Exosomes Derived From Pancreatic Stellate Cells: MicroRNA Signature and Effects on Pancreatic Cancer Cells.

    Science.gov (United States)

    Takikawa, Tetsuya; Masamune, Atsushi; Yoshida, Naoki; Hamada, Shin; Kogure, Takayuki; Shimosegawa, Tooru

    2017-01-01

    Pancreatic stellate cells (PSCs) interact with pancreatic cancer cells in the tumor microenvironment. Cell constituents including microRNAs may be exported from cells within membranous nanovesicles termed exosomes. Exosomes might play a pivotal role in intercellular communication. This study aimed to clarify the microRNA signature of PSC-derived exosomes and their effects on pancreatic cancer cells. Exosomes were prepared from the conditioned medium of immortalized human PSCs. MicroRNAs were prepared from the exosomes and their source PSCs, and the microRNA expression profiles were compared by microarray. The effects of PSC-derived exosomes on proliferation, migration, and the mRNA expression profiles were examined in pancreatic cancer cells. Pancreatic stellate cell-derived exosomes contained a variety of microRNAs including miR-21-5p. Several microRNAs such as miR-451a were enriched in exosomes compared to their source PSCs. Pancreatic stellate cell-derived exosomes stimulated the proliferation, migration and expression of mRNAs for chemokine (C - X - C motif) ligands 1 and 2 in pancreatic cancer cells. The stimulation of proliferation, migration, and chemokine gene expression by the conditioned medium of PSCs was suppressed by GW4869, an exosome inhibitor. We clarified the microRNA expression profile in PSC-derived exosomes. Pancreatic stellate cell-derived exosomes might play a role in the interactions between PSCs and pancreatic cancer cells.

  7. Endocrine pancreatic function changes after acute pancreatitis.

    Science.gov (United States)

    Wu, Deqing; Xu, Yaping; Zeng, Yue; Wang, Xingpeng

    2011-10-01

    This study aimed to investigate the impairment of pancreatic endocrine function and the associated risk factors after acute pancreatitis (AP). Fifty-nine patients were subjected to tests of pancreatic function after an attack of pancreatitis. The mean time after the event was 3.5 years. Pancreatic endocrine function was evaluated by fasting blood glucose (FBG), glycosylated hemoglobin, fasting blood insulin, and C-peptide. Homeostasis model assessment was used to evaluate insulin resistance and islet β-cell function. Pancreatic exocrine function was evaluated by fecal elastase 1. Factors that could influence endocrine function were also investigated. Nineteen patients (32%) were found to have elevated FBG, whereas 5 (8%) had abnormal glycosylated hemoglobin levels. The levels of FBG, fasting blood insulin, and C-peptide were higher in patients than in controls (P endocrine insufficiency. Pancreatic exocrine functional impairment was found at the same time. Endocrine functional impairment with insulin resistance was found in patients after AP. Obesity, hyperlipidemia, and diabetes-related symptoms increased the likelihood of developing functional impairment after AP.

  8. In vitro modeling of human pancreatic duct epithelial cell transformation defines gene expression changes induced by K-ras oncogenic activation in pancreatic carcinogenesis.

    Science.gov (United States)

    Qian, Jiaying; Niu, Jiangong; Li, Ming; Chiao, Paul J; Tsao, Ming-Sound

    2005-06-15

    Genetic analysis of pancreatic ductal adenocarcinomas and their putative precursor lesions, pancreatic intraepithelial neoplasias (PanIN), has shown a multistep molecular paradigm for duct cell carcinogenesis. Mutational activation or inactivation of the K-ras, p16(INK4A), Smad4, and p53 genes occur at progressive and high frequencies in these lesions. Oncogenic activation of the K-ras gene occurs in >90% of pancreatic ductal carcinoma and is found early in the PanIN-carcinoma sequence, but its functional roles remain poorly understood. We show here that the expression of K-ras(G12V) oncogene in a near diploid HPV16-E6E7 gene immortalized human pancreatic duct epithelial cell line originally derived from normal pancreas induced the formation of carcinoma in 50% of severe combined immunodeficient mice implanted with these cells. A tumor cell line established from one of these tumors formed ductal cancer when implanted orthotopically. These cells also showed increased activation of the mitogen-activated protein kinase, AKT, and nuclear factor-kappaB pathways. Microarray expression profiling studies identified 584 genes whose expression seemed specifically up-regulated by the K-ras oncogene expression. Forty-two of these genes have been reported previously as differentially overexpressed in pancreatic cancer cell lines or primary tumors. Real-time PCR confirmed the overexpression of a large number of these genes. Immunohistochemistry done on tissue microarrays constructed from PanIN and pancreatic cancer samples showed laminin beta3 overexpression starting in high-grade PanINs and occurring in >90% of pancreatic ductal carcinoma. The in vitro modeling of human pancreatic duct epithelial cell transformation may provide mechanistic insights on gene expression changes that occur during multistage pancreatic duct cell carcinogenesis.

  9. Selective destruction of mouse islet beta cells by human T lymphocytes in a newly-established humanized type 1 diabetic model

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yong, E-mail: yongzhao@uic.edu [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Guo, Chengshan; Hwang, David; Lin, Brian; Dingeldein, Michael; Mihailescu, Dan; Sam, Susan; Sidhwani, Seema [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Zhang, Yongkang [Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Jain, Sumit [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Skidgel, Randal A. [Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Prabhakar, Bellur S. [Department of Immunology and Microbiology, University of Illinois at Chicago, Chicago, IL 60612 (United States); Mazzone, Theodore [Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612 (United States); Holterman, Mark J. [Department of Surgery, University of Illinois at Chicago, Chicago, IL 60612 (United States)

    2010-09-03

    Research highlights: {yields} Establish a human immune-mediated type 1 diabetic model in NOD-scid IL2r{gamma}{sup null} mice. {yields} Using the irradiated diabetic NOD mouse spleen mononuclear cells as trigger. {yields} The islet {beta} cells were selectively destroyed by infiltrated human T cells. {yields} The model can facilitate translational research to find a cure for type 1 diabetes. -- Abstract: Type 1 diabetes (T1D) is caused by a T cell-mediated autoimmune response that leads to the loss of insulin-producing {beta} cells. The optimal preclinical testing of promising therapies would be aided by a humanized immune-mediated T1D model. We develop this model in NOD-scid IL2r{gamma}{sup null} mice. The selective destruction of pancreatic islet {beta} cells was mediated by human T lymphocytes after an initial trigger was supplied by the injection of irradiated spleen mononuclear cells (SMC) from diabetic nonobese diabetic (NOD) mice. This resulted in severe insulitis, a marked loss of total {beta}-cell mass, and other related phenotypes of T1D. The migration of human T cells to pancreatic islets was controlled by the {beta} cell-produced highly conserved chemokine stromal cell-derived factor 1 (SDF-1) and its receptor C-X-C chemokine receptor (CXCR) 4, as demonstrated by in vivo blocking experiments using antibody to CXCR4. The specificity of humanized T cell-mediated immune responses against islet {beta} cells was generated by the local inflammatory microenvironment in pancreatic islets including human CD4{sup +} T cell infiltration and clonal expansion, and the mouse islet {beta}-cell-derived CD1d-mediated human iNKT activation. The selective destruction of mouse islet {beta} cells by a human T cell-mediated immune response in this humanized T1D model can mimic those observed in T1D patients. This model can provide a valuable tool for translational research into T1D.

  10. Expansion of Adult Human Pancreatic Tissue Yields Organoids Harboring Progenitor Cells with Endocrine Differentiation Potential

    Directory of Open Access Journals (Sweden)

    Cindy J.M. Loomans

    2018-03-01

    Full Text Available Summary: Generating an unlimited source of human insulin-producing cells is a prerequisite to advance β cell replacement therapy for diabetes. Here, we describe a 3D culture system that supports the expansion of adult human pancreatic tissue and the generation of a cell subpopulation with progenitor characteristics. These cells display high aldehyde dehydrogenase activity (ALDHhi, express pancreatic progenitors markers (PDX1, PTF1A, CPA1, and MYC, and can form new organoids in contrast to ALDHlo cells. Interestingly, gene expression profiling revealed that ALDHhi cells are closer to human fetal pancreatic tissue compared with adult pancreatic tissue. Endocrine lineage markers were detected upon in vitro differentiation. Engrafted organoids differentiated toward insulin-positive (INS+ cells, and circulating human C-peptide was detected upon glucose challenge 1 month after transplantation. Engrafted ALDHhi cells formed INS+ cells. We conclude that adult human pancreatic tissue has potential for expansion into 3D structures harboring progenitor cells with endocrine differentiation potential. : In the context of β cell replacement therapy for diabetes, de Koning and colleagues describe a 3D culture platform that supports ex vivo expansion of human pancreatic tissue as organoids. These organoids harbor a subpopulation of ALDHhi cells that display proliferative capacity and can differentiate to an endocrine fate. Keywords: pancreas, organoid, human, ALDH, endocrine differentiation, beta cells, insulin, progenitor, fetal, diabetes

  11. D-saccharic acid-1,4-lactone ameliorates alloxan-induced diabetes mellitus and oxidative stress in rats through inhibiting pancreatic beta-cells from apoptosis via mitochondrial dependent pathway

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Semantee [Department of Life Sciences and Biotechnology, Jadavpur University, 188, Raja S C Mullick Road, Kolkata 700 032 (India); Manna, Prasenjit [Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata-700054 (India); Gachhui, Ratan [Department of Life Sciences and Biotechnology, Jadavpur University, 188, Raja S C Mullick Road, Kolkata 700 032 (India); Sil, Parames C., E-mail: parames@bosemain.boseinst.ac.in [Division of Molecular Medicine, Bose Institute, P-1/12, CIT Scheme VII M, Kolkata-700054 (India)

    2011-12-15

    Oxidative stress plays a vital role in diabetic complications. To suppress the oxidative stress mediated damage in diabetic pathophysiology, a special focus has been given on naturally occurring antioxidants present in normal diet. D-saccharic acid 1,4-lactone (DSL), a derivative of D-glucaric acid, is present in many dietary plants and is known for its detoxifying and antioxidant properties. The aim of the present study was to evaluate the beneficial role of DSL against alloxan (ALX) induced diabetes in the pancreas tissue of Swiss albino rats. A dose-dependent study for DSL (20-120 mg/kg body weight) was carried out to find the effective dose of the compound in ALX-induced diabetic rats. ALX exposure elevated the blood glucose, glycosylated Hb, decreased the plasma insulin and disturbed the intra-cellular antioxidant machineries whereas oral administration of DSL at a dose of 80 mg/kg body weight restored these alterations close to normal. Investigating the mechanism of the protective activity of DSL we observed that it prevented the pancreatic {beta}-cell apoptosis via mitochondria-dependent pathway. Results showed decreased mitochondrial membrane potential, enhanced cytochrome c release in the cytosol and reciprocal regulation of Bcl-2 family proteins in the diabetic rats. These events were also found to be associated with increased level of Apaf-1, caspase 9, and caspase 3 that ultimately led to pancreatic {beta}-cell apoptosis. DSL treatment, however, counteracted these changes. In conclusion, DSL possesses the capability of ameliorating the oxidative stress in ALX-induced diabetes and thus could be a promising approach in lessening diabetic complications. Highlights: Black-Right-Pointing-Pointer Oxidative stress is suggested as a key event in the pathogenesis of diabetes. Black-Right-Pointing-Pointer D-saccharic acid 1,4-lactone (DSL) reduces the alloxan-induced diabetes mellitus. Black-Right-Pointing-Pointer DSL normalizes cellular antioxidant machineries

  12. Central infusion of leptin improves insulin resistance and suppresses beta-cell function, but not beta-cell mass, primarily through the sympathetic nervous system in a type 2 diabetic rat model.

    Science.gov (United States)

    Park, Sunmin; Ahn, Il Sung; Kim, Da Sol

    2010-06-05

    We investigated whether hypothalamic leptin alters beta-cell function and mass directly via the sympathetic nervous system (SNS) or indirectly as the result of altered insulin resistant states. The 90% pancreatectomized male Sprague Dawley rats had sympathectomy into the pancreas by applying phenol into the descending aorta (SNSX) or its sham operation (Sham). Each group was divided into two sections, receiving either leptin at 300ng/kgbw/h or artificial cerebrospinal fluid (aCSF) via intracerebroventricular (ICV) infusion for 3h as a short-term study. After finishing the infusion study, ICV leptin (3mug/kg bw/day) or ICV aCSF (control) was infused in rats fed 30 energy % fat diets by osmotic pump for 4weeks. At the end of the long-term study, glucose-stimulated insulin secretion and islet morphometry were analyzed. Acute ICV leptin administration in Sham rats, but not in SNSX rats, suppressed the first- and second-phase insulin secretion at hyperglycemic clamp by about 48% compared to the control. Regardless of SNSX, the 4-week administration of ICV leptin improved glucose tolerance during oral glucose tolerance tests and insulin sensitivity at hyperglycemic clamp, compared to the control, while it suppressed second-phase insulin secretion in Sham rats but not in SNSX rats. However, the pancreatic beta-cell area and mass were not affected by leptin and SNSX, though ICV leptin decreased individual beta-cell size and concomitantly increased beta-cell apoptosis in Sham rats. Leptin directly decreases insulin secretion capacity mainly through the activation of SNS without modulating pancreatic beta-cell mass.

  13. Sleep apnea predicts distinct alterations in glucose homeostasis and biomarkers in obese adults with normal and impaired glucose metabolism

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    Hill Nathan R

    2010-12-01

    Full Text Available Abstract Background Notwithstanding previous studies supporting independent associations between obstructive sleep apnea (OSA and prevalence of diabetes, the underlying pathogenesis of impaired glucose regulation in OSA remains unclear. We explored mechanisms linking OSA with prediabetes/diabetes and associated biomarker profiles. We hypothesized that OSA is associated with distinct alterations in glucose homeostasis and biomarker profiles in subjects with normal (NGM and impaired glucose metabolism (IGM. Methods Forty-five severely obese adults (36 women without certain comorbidities/medications underwent anthropometric measurements, polysomnography, and blood tests. We measured fasting serum glucose, insulin, selected cytokines, and calculated homeostasis model assessment estimates of insulin sensitivity (HOMA-IS and pancreatic beta-cell function (HOMA-B. Results Both increases in apnea-hypopnea index (AHI and the presence of prediabetes/diabetes were associated with reductions in HOMA-IS in the entire cohort even after adjustment for sex, race, age, and BMI (P = 0.003. In subjects with NGM (n = 30, OSA severity was associated with significantly increased HOMA-B (a trend towards decreased HOMA-IS independent of sex and adiposity. OSA-related oxyhemoglobin desaturations correlated with TNF-α (r=-0.76; P = 0.001 in women with NGM and with IL-6 (rho=-0.55; P = 0.035 in women with IGM (n = 15 matched individually for age, adiposity, and AHI. Conclusions OSA is independently associated with altered glucose homeostasis and increased basal beta-cell function in severely obese adults with NGM. The findings suggest that moderate to severe OSA imposes an excessive functional demand on pancreatic beta-cells, which may lead to their exhaustion and impaired secretory capacity over time. The two distinct biomarker profiles linking sleep apnea with NGM and IGM via TNF-α and IL-6 have been discerned in our study to suggest that sleep apnea and particularly

  14. Insulin Resistance and Impaired Pancreatic β-Cell Function in Adult Offspring of Women With Diabetes in Pregnancy

    DEFF Research Database (Denmark)

    Kelstrup, Louise; Damm, Peter; Mathiesen, Elisabeth R

    2013-01-01

    Context:Offspring of women with diabetes during pregnancy have increased risk of glucose intolerance in adulthood, but the underlying mechanisms are unknown.Objective:We aimed to investigate effects of intrauterine hyperglycemia on insulin secretion and - action in adult offspring of mothers...... a standard oral glucose tolerance test (120 minutes, 75 gram glucose). Pancreatic beta-cell function taking the prevailing insulin sensitivity into account was estimated by disposition indices.Results:Both groups of offspring exposed during pregnancy to either maternal gestational diabetes or type 1 diabetes.......005).Conclusion:Reduced insulin sensitivity as well as impaired pancreatic beta cell function may contribute to the increased risk of glucose intolerance among adult offspring born to women with diabetes during pregnancy....

  15. Oxidative Metabolism Genes Are Not Responsive to Oxidative Stress in Rodent Beta Cell Lines

    Directory of Open Access Journals (Sweden)

    Faer Morrison

    2012-01-01

    Full Text Available Altered expression of oxidative metabolism genes has been described in the skeletal muscle of individuals with type 2 diabetes. Pancreatic beta cells contain low levels of antioxidant enzymes and are particularly susceptible to oxidative stress. In this study, we explored the effect of hyperglycemia-induced oxidative stress on a panel of oxidative metabolism genes in a rodent beta cell line. We exposed INS-1 rodent beta cells to low (5.6 mmol/L, ambient (11 mmol/L, and high (28 mmol/L glucose conditions for 48 hours. Increases in oxidative stress were measured using the fluorescent probe dihydrorhodamine 123. We then measured the expression levels of a panel of 90 oxidative metabolism genes by real-time PCR. Elevated reactive oxygen species (ROS production was evident in INS-1 cells after 48 hours (P<0.05. TLDA analysis revealed a significant (P<0.05 upregulation of 16 of the 90 genes under hyperglycemic conditions, although these expression differences did not reflect differences in ROS. We conclude that although altered glycemia may influence the expression of some oxidative metabolism genes, this effect is probably not mediated by increased ROS production. The alterations to the expression of oxidative metabolism genes previously observed in human diabetic skeletal muscle do not appear to be mirrored in rodent pancreatic beta cells.

  16. Pancreas-Specific Sirt1-Deficiency in Mice Compromises Beta-Cell Function without Development of Hyperglycemia.

    Science.gov (United States)

    Pinho, Andreia V; Bensellam, Mohammed; Wauters, Elke; Rees, Maxine; Giry-Laterriere, Marc; Mawson, Amanda; Ly, Le Quan; Biankin, Andrew V; Wu, Jianmin; Laybutt, D Ross; Rooman, Ilse

    2015-01-01

    Sirtuin 1 (Sirt1) has been reported to be a critical positive regulator of glucose-stimulated insulin secretion in pancreatic beta-cells. The effects on islet cells and blood glucose levels when Sirt1 is deleted specifically in the pancreas are still unclear. This study examined islet glucose responsiveness, blood glucose levels, pancreatic islet histology and gene expression in Pdx1Cre; Sirt1ex4F/F mice that have loss of function and loss of expression of Sirt1 specifically in the pancreas. We found that in the Pdx1Cre; Sirt1ex4F/F mice, the relative insulin positive area and the islet size distribution were unchanged. However, beta-cells were functionally impaired, presenting with lower glucose-stimulated insulin secretion. This defect was not due to a reduced expression of insulin but was associated with a decreased expression of the glucose transporter Slc2a2/Glut2 and of the Glucagon like peptide-1 receptor (Glp1r) as well as a marked down regulation of endoplasmic reticulum (ER) chaperones that participate in the Unfolded Protein Response (UPR) pathway. Counter intuitively, the Sirt1-deficient mice did not develop hyperglycemia. Pancreatic polypeptide (PP) cells were the only other islet cells affected, with reduced numbers in the Sirt1-deficient pancreas. This study provides new mechanistic insights showing that beta-cell function in Sirt1-deficient pancreas is affected due to altered glucose sensing and deregulation of the UPR pathway. Interestingly, we uncovered a context in which impaired beta-cell function is not accompanied by increased glycemia. This points to a unique compensatory mechanism. Given the reduction in PP, investigation of its role in the control of blood glucose is warranted.

  17. Pancreas-Specific Sirt1-Deficiency in Mice Compromises Beta-Cell Function without Development of Hyperglycemia.

    Directory of Open Access Journals (Sweden)

    Andreia V Pinho

    Full Text Available Sirtuin 1 (Sirt1 has been reported to be a critical positive regulator of glucose-stimulated insulin secretion in pancreatic beta-cells. The effects on islet cells and blood glucose levels when Sirt1 is deleted specifically in the pancreas are still unclear.This study examined islet glucose responsiveness, blood glucose levels, pancreatic islet histology and gene expression in Pdx1Cre; Sirt1ex4F/F mice that have loss of function and loss of expression of Sirt1 specifically in the pancreas.We found that in the Pdx1Cre; Sirt1ex4F/F mice, the relative insulin positive area and the islet size distribution were unchanged. However, beta-cells were functionally impaired, presenting with lower glucose-stimulated insulin secretion. This defect was not due to a reduced expression of insulin but was associated with a decreased expression of the glucose transporter Slc2a2/Glut2 and of the Glucagon like peptide-1 receptor (Glp1r as well as a marked down regulation of endoplasmic reticulum (ER chaperones that participate in the Unfolded Protein Response (UPR pathway. Counter intuitively, the Sirt1-deficient mice did not develop hyperglycemia. Pancreatic polypeptide (PP cells were the only other islet cells affected, with reduced numbers in the Sirt1-deficient pancreas.This study provides new mechanistic insights showing that beta-cell function in Sirt1-deficient pancreas is affected due to altered glucose sensing and deregulation of the UPR pathway. Interestingly, we uncovered a context in which impaired beta-cell function is not accompanied by increased glycemia. This points to a unique compensatory mechanism. Given the reduction in PP, investigation of its role in the control of blood glucose is warranted.

  18. Efficient Generation of Glucose-Responsive Beta Cells from Isolated GP2+ Human Pancreatic Progenitors

    Directory of Open Access Journals (Sweden)

    Jacqueline Ameri

    2017-04-01

    Full Text Available Stem cell-based therapy for type 1 diabetes would benefit from implementation of a cell purification step at the pancreatic endoderm stage. This would increase the safety of the final cell product, allow the establishment of an intermediate-stage stem cell bank, and provide a means for upscaling β cell manufacturing. Comparative gene expression analysis revealed glycoprotein 2 (GP2 as a specific cell surface marker for isolating pancreatic endoderm cells (PECs from differentiated hESCs and human fetal pancreas. Isolated GP2+ PECs efficiently differentiated into glucose responsive insulin-producing cells in vitro. We found that in vitro PEC proliferation declines due to enhanced expression of the cyclin-dependent kinase (CDK inhibitors CDKN1A and CDKN2A. However, we identified a time window when reducing CDKN1A or CDKN2A expression increased proliferation and yield of GP2+ PECs. Altogether, our results contribute tools and concepts toward the isolation and use of PECs as a source for the safe production of hPSC-derived β cells.

  19. Pancreatic beta-cell function is a stronger predictor of changes in glycemic control after an aerobic exercise intervention than insulin sensitivity

    DEFF Research Database (Denmark)

    Solomon, Thomas; Malin, Steven K; Karstoft, Kristian

    2013-01-01

    glucose-stimulated insulin secretion (GSIS), and disposition index (DI) were measured following 12-16-weeks of aerobic exercise training. Regression analyses were used to identify relationships between variables.ResultsFollowing training, 86% of subjects increased VO2max and lost weight. HbA1c, fasting......ContextUnderstanding inter-subject variability in glycemic control following exercise training will help individualize treatment.ObjectiveTo determine whether this variability is related to training-induced changes in insulin sensitivity or pancreatic beta-cell function.Design, Setting....... Training increased first- and second-phase DI in 83% and 74% of subjects. Training-induced changes in glycemic control were related to changes in GSIS (P...

  20. Lactate overrides central nervous but not beta-cell glucose sensing in humans.

    Science.gov (United States)

    Schmid, Sebastian M; Jauch-Chara, Kamila; Hallschmid, Manfred; Oltmanns, Kerstin M; Peters, Achim; Born, Jan; Schultes, Bernd

    2008-12-01

    Lactate has been shown to serve as an alternative energy substrate in the central nervous system and to interact with hypothalamic glucose sensors. On the background of marked similarities between central nervous and beta-cell glucose sensing, we examined whether lactate also interacts with pancreatic glucose-sensing mechanisms in vivo. The effects of intravenously infused lactate vs placebo (saline) on central nervous and pancreatic glucose sensing were assessed during euglycemic and hypoglycemic clamp experiments in 10 healthy men. The release of neuroendocrine counterregulatory hormones during hypoglycemia was considered to reflect central nervous glucose sensing, whereas endogenous insulin secretion as assessed by serum C-peptide levels served as an indicator of pancreatic beta-cell glucose sensing. Lactate infusion blunted the counterregulatory hormonal responses to hypoglycemia, in particular, the release of epinephrine (P = .007) and growth hormone (P = .004), so that higher glucose infusion rates (P = .012) were required to maintain the target blood glucose levels. In contrast, the decrease in C-peptide concentrations during the hypoglycemic clamp remained completely unaffected by lactate (P = .60). During euglycemic clamp conditions, lactate infusion did not affect the concentrations of C-peptide and of counterregulatory hormones, with the exception of norepinephrine levels that were lower during lactate than saline infusion (P = .049) independently of the glycemic condition. Data indicate that glucose sensing of beta-cells is specific to glucose, whereas glucose sensing at the central nervous level can be overridden by lactate, reflecting the brain's ability to rely on lactate as an alternative major energy source.

  1. Disruption of growth hormone receptor gene causes diminished pancreatic islet size and increased insulin sensitivity in mice.

    Science.gov (United States)

    Liu, Jun-Li; Coschigano, Karen T; Robertson, Katie; Lipsett, Mark; Guo, Yubin; Kopchick, John J; Kumar, Ujendra; Liu, Ye Lauren

    2004-09-01

    Growth hormone, acting through its receptor (GHR), plays an important role in carbohydrate metabolism and in promoting postnatal growth. GHR gene-deficient (GHR(-/-)) mice exhibit severe growth retardation and proportionate dwarfism. To assess the physiological relevance of growth hormone actions, GHR(-/-) mice were used to investigate their phenotype in glucose metabolism and pancreatic islet function. Adult GHR(-/-) mice exhibited significant reductions in the levels of blood glucose and insulin, as well as insulin mRNA accumulation. Immunohistochemical analysis of pancreatic sections revealed normal distribution of the islets despite a significantly smaller size. The average size of the islets found in GHR(-/-) mice was only one-third of that in wild-type littermates. Total beta-cell mass was reduced 4.5-fold in GHR(-/-) mice, significantly more than their body size reduction. This reduction in pancreatic islet mass appears to be related to decreases in proliferation and cell growth. GHR(-/-) mice were different from the human Laron syndrome in serum insulin level, insulin responsiveness, and obesity. We conclude that growth hormone signaling is essential for maintaining pancreatic islet size, stimulating islet hormone production, and maintaining normal insulin sensitivity and glucose homeostasis.

  2. Glucose Homeostasis, Pancreatic Endocrine Function, and Outcomes in Advanced Heart Failure.

    Science.gov (United States)

    Melenovsky, Vojtech; Benes, Jan; Franekova, Janka; Kovar, Jan; Borlaug, Barry A; Segetova, Marketa; Tura, Andrea; Pelikanova, Tereza

    2017-08-07

    The mechanisms and relevance of impaired glucose homeostasis in advanced heart failure (HF) are poorly understood. The study goals were to examine glucose regulation, pancreatic endocrine function, and metabolic factors related to prognosis in patients with nondiabetic advanced HF. In total, 140 advanced HF patients without known diabetes mellitus and 21 sex-, age-, and body mass index-matched controls underwent body composition assessment, oral glucose tolerance testing, and measurement of glucose-regulating hormones to model pancreatic β-cell secretory response. Compared with controls, HF patients had similar fasting glucose and insulin levels but higher levels after oral glucose tolerance testing. Insulin secretion was not impaired, but with increasing HF severity, there was a reduction in glucose, insulin, and insulin/glucagon ratio-a signature of starvation. The insulin/C-peptide ratio was decreased in HF, indicating enhanced insulin clearance, and this was correlated with lower cardiac output, hepatic insufficiency, right ventricular dysfunction, and body wasting. After a median of 449 days, 41% of patients experienced an adverse event (death, urgent transplant, or assist device). Increased glucagon and, paradoxically, low fasting plasma glucose displayed the strongest relations to outcome ( P =0.01). Patients in the lowest quartile of fasting plasma glucose (3.8-5.1 mmol·L -1 , 68-101 mg·dL -1 ) had 3-times higher event risk than in the top quartile (6.0-7.9 mmol·L -1 , 108-142 mg·dL -1 ; relative risk: 3.05 [95% confidence interval, 1.46-6.77]; P =0.002). Low fasting plasma glucose and increased glucagon are robust metabolic predictors of adverse events in advanced HF. Pancreatic insulin secretion is preserved in advanced HF, but levels decrease with increasing HF severity due to enhanced insulin clearance that is coupled with right heart failure and cardiac cachexia. © 2017 The Authors. Published on behalf of the American Heart Association, Inc

  3. Interactions between the metabolism of L-leucine and D-glucose in the pancreatic. beta. -cells

    Energy Technology Data Exchange (ETDEWEB)

    Gylfe, E; Sehlin, J [Umeaa Univ. (Sweden). Dept. of Histology

    1976-01-01

    ..beta..-cell-rich pancreatic islets microdissected from obese-hyperglycemic mice were used to study interactions between the metabolism of L-leucine and D-glucose. L-leucine reduced the islet content of aspartic acid whereas D-glucose, when added to L-leucine-incubated islets, increased the contents of aspartic acid and ..gamma..-aminobutyric acid (GABA). D-glucose also increased the incorporation of L-leucine carbon into aspartic acid, GABA and glutamic acid, suggesting stimulation of a malate shuttle mechanism. When expressed per mole of the individual amino acids, the incorporation of L-leucine carbon into GABA was 2.5 - 4 times higher than into glutamic acid indicating intracellular compartmentation of the latter amino acid. Both L-leucine and D-leucine stimulated /sup 14/CO/sub 2/ production from /sup 14/C-labelled D-glucose. L-leucine did not affect /sup 3/H/sub 2/O production from tritiated D-glucose. The present data do not indicate a role of other amino acids or D-glucose in L-leucine-stimulated insulin release.

  4. Role of nutrients and mTOR signaling in the regulation of pancreatic progenitors development

    Directory of Open Access Journals (Sweden)

    Lynda Elghazi

    2017-06-01

    Full Text Available Objective: Poor fetal nutrition increases the risk of type 2 diabetes in the offspring at least in part by reduced embryonic β-cell growth and impaired function. However, it is not entirely clear how fetal nutrients and growth factors impact β-cells during development to alter glucose homeostasis and metabolism later in life. The current experiments aimed to test the impact of fetal nutrients and growth factors on endocrine development and how these signals acting on mTOR signaling regulate β-cell mass and glucose homeostasis. Method: Pancreatic rudiments in culture were used to study the role of glucose, growth factors, and amino acids on β-cell development. The number and proliferation of pancreatic and endocrine progenitor were assessed in the presence or absence of rapamycin. The impact of mTOR signaling in vivo on pancreas development and glucose homeostasis was assessed in models deficient for mTOR or Raptor in Pdx1 expressing pancreatic progenitors. Results: We found that amino acid concentrations, and leucine in particular, enhance the number of pancreatic and endocrine progenitors and are essential for growth factor induced proliferation. Rapamycin, an mTORC1 complex inhibitor, reduced the number and proliferation of pancreatic and endocrine progenitors. Mice lacking mTOR in pancreatic progenitors exhibited hyperglycemia in neonates, hypoinsulinemia and pancreatic agenesis/hypoplasia with pancreas rudiments containing ductal structures lacking differentiated acinar and endocrine cells. In addition, loss of mTORC1 by deletion of raptor in pancreatic progenitors reduced pancreas size with reduced number of β-cells. Conclusion: Together, these results suggest that amino acids concentrations and in particular leucine modulates growth responses of pancreatic and endocrine progenitors and that mTOR signaling is critical for these responses. Inactivation of mTOR and raptor in pancreatic progenitors suggested that alterations in some of

  5. T Cell-Mediated Beta Cell Destruction: Autoimmunity and Alloimmunity in the Context of Type 1 Diabetes

    Directory of Open Access Journals (Sweden)

    Adam L. Burrack

    2017-12-01

    Full Text Available Type 1 diabetes (T1D results from destruction of pancreatic beta cells by T cells of the immune system. Despite improvements in insulin analogs and continuous blood glucose level monitoring, there is no cure for T1D, and some individuals develop life-threatening complications. Pancreas and islet transplantation have been attractive therapeutic approaches; however, transplants containing insulin-producing cells are vulnerable to both recurrent autoimmunity and conventional allograft rejection. Current immune suppression treatments subdue the immune system, but not without complications. Ideally a successful approach would target only the destructive immune cells and leave the remaining immune system intact to fight foreign pathogens. This review discusses the autoimmune diabetes disease process, diabetic complications that warrant a transplant, and alloimmunity. First, we describe the current understanding of autoimmune destruction of beta cells including the roles of CD4 and CD8 T cells and several possibilities for antigen-specific tolerance induction. Second, we outline diabetic complications necessitating beta cell replacement. Third, we discuss transplant recognition, potential sources for beta cell replacement, and tolerance-promoting therapies under development. We hypothesize that a better understanding of autoreactive T cell targets during disease pathogenesis and alloimmunity following transplant destruction could enhance attempts to re-establish tolerance to beta cells.

  6. Targeting Apoptosis Signaling in Pancreatic Cancer

    International Nuclear Information System (INIS)

    Fulda, Simone

    2011-01-01

    The ability to escape apoptosis or programmed cell death is a hallmark of human cancers, for example pancreatic cancer. This can promote tumorigenesis, since too little cell death by apoptosis disturbs tissue homeostasis. Additionally, defective apoptosis signaling is the underlying cause of failure to respond to current treatment approaches, since therapy-mediated antitumor activity requires the intactness of apoptosis signaling pathways in cancer cells. Thus, the elucidation of defects in the regulation of apoptosis in pancreatic carcinoma can result in the identification of novel targets for therapeutic interference and for exploitation for cancer drug discovery

  7. Targeting Apoptosis Signaling in Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Fulda, Simone [Institute for Experimental Cancer Research in Pediatrics, Goethe-University Frankfurt, Komturstr. 3a, 60528 Frankfurt (Germany)

    2011-01-11

    The ability to escape apoptosis or programmed cell death is a hallmark of human cancers, for example pancreatic cancer. This can promote tumorigenesis, since too little cell death by apoptosis disturbs tissue homeostasis. Additionally, defective apoptosis signaling is the underlying cause of failure to respond to current treatment approaches, since therapy-mediated antitumor activity requires the intactness of apoptosis signaling pathways in cancer cells. Thus, the elucidation of defects in the regulation of apoptosis in pancreatic carcinoma can result in the identification of novel targets for therapeutic interference and for exploitation for cancer drug discovery.

  8. Plasticity of adult human pancreatic duct cells by neurogenin3-mediated reprogramming.

    Directory of Open Access Journals (Sweden)

    Nathalie Swales

    Full Text Available AIMS/HYPOTHESIS: Duct cells isolated from adult human pancreas can be reprogrammed to express islet beta cell genes by adenoviral transduction of the developmental transcription factor neurogenin3 (Ngn3. In this study we aimed to fully characterize the extent of this reprogramming and intended to improve it. METHODS: The extent of the Ngn3-mediated duct-to-endocrine cell reprogramming was measured employing genome wide mRNA profiling. By modulation of the Delta-Notch signaling or addition of pancreatic endocrine transcription factors Myt1, MafA and Pdx1 we intended to improve the reprogramming. RESULTS: Ngn3 stimulates duct cells to express a focused set of genes that are characteristic for islet endocrine cells and/or neural tissues. This neuro-endocrine shift however, is incomplete with less than 10% of full duct-to-endocrine reprogramming achieved. Transduction of exogenous Ngn3 activates endogenous Ngn3 suggesting auto-activation of this gene. Furthermore, pancreatic endocrine reprogramming of human duct cells can be moderately enhanced by inhibition of Delta-Notch signaling as well as by co-expressing the transcription factor Myt1, but not MafA and Pdx1. CONCLUSIONS/INTERPRETATION: The results provide further insight into the plasticity of adult human duct cells and suggest measurable routes to enhance Ngn3-mediated in vitro reprogramming protocols for regenerative beta cell therapy in diabetes.

  9. Pancreatic Fat Is Associated With Metabolic Syndrome and Visceral Fat but Not Beta-Cell Function or Body Mass Index in Pediatric Obesity.

    Science.gov (United States)

    Staaf, Johan; Labmayr, Viktor; Paulmichl, Katharina; Manell, Hannes; Cen, Jing; Ciba, Iris; Dahlbom, Marie; Roomp, Kirsten; Anderwald, Christian-Heinz; Meissnitzer, Matthias; Schneider, Reinhard; Forslund, Anders; Widhalm, Kurt; Bergquist, Jonas; Ahlström, Håkan; Bergsten, Peter; Weghuber, Daniel; Kullberg, Joel

    2017-03-01

    Adolescents with obesity have increased risk of type 2 diabetes and metabolic syndrome (MetS). Pancreatic fat has been related to these conditions; however, little is known about associations in pediatric obesity. The present study was designed to explore these associations further. We examined 116 subjects, 90 with obesity. Anthropometry, MetS, blood samples, and oral glucose tolerance tests were assessed using standard techniques. Pancreatic fat fraction (PFF) and other fat depots were quantified using magnetic resonance imaging. The PFF was elevated in subjects with obesity. No association between PFF and body mass index-standard deviation score (BMI-SDS) was found in the obesity subcohort. Pancreatic fat fraction correlated to Insulin Secretion Sensitivity Index-2 and Homeostatic Model Assessment of Insulin Resistance in simple regression; however, when using adjusted regression and correcting for BMI-SDS and other fat compartments, PFF correlated only to visceral adipose tissue and fasting glucose. Highest levels of PFF were found in subjects with obesity and MetS. In adolescents with obesity, PFF is elevated and associated to MetS, fasting glucose, and visceral adipose tissue but not to beta-cell function, glucose tolerance, or BMI-SDS. This study demonstrates that conclusions regarding PFF and its associations depend on the body mass features of the cohort.

  10. Efficient Generation of NKX6-1+ Pancreatic Progenitors from Multiple Human Pluripotent Stem Cell Lines

    Directory of Open Access Journals (Sweden)

    M. Cristina Nostro

    2015-04-01

    Full Text Available Human pluripotent stem cells (hPSCs represent a renewable source of pancreatic beta cells for both basic research and therapeutic applications. Given this outstanding potential, significant efforts have been made to identify the signaling pathways that regulate pancreatic development in hPSC differentiation cultures. In this study, we demonstrate that the combination of epidermal growth factor (EGF and nicotinamide signaling induces the generation of NKX6-1+ progenitors from all hPSC lines tested. Furthermore, we show that the size of the NKX6-1+ population is regulated by the duration of treatment with retinoic acid, fibroblast growth factor 10 (FGF10, and inhibitors of bone morphogenetic protein (BMP and hedgehog signaling pathways. When transplanted into NOD scid gamma (NSG recipients, these progenitors differentiate to give rise to exocrine and endocrine cells, including monohormonal insulin+ cells. Together, these findings provide an efficient and reproducible strategy for generating highly enriched populations of hPSC-derived beta cell progenitors for studies aimed at further characterizing their developmental potential in vivo and deciphering the pathways that regulate their maturation in vitro.

  11. Three-component homeostasis control

    Science.gov (United States)

    Xu, Jin; Hong, Hyunsuk; Jo, Junghyo

    2014-03-01

    Two reciprocal components seem to be sufficient to maintain a control variable constant. However, pancreatic islets adapt three components to control glucose homeostasis. They are α (secreting glucagon), β (insulin), and δ (somatostatin) cells. Glucagon and insulin are the reciprocal hormones for increasing and decreasing blood glucose levels, while the role of somatostatin is unknown. However, it has been known how each hormone affects other cell types. Based on the pulsatile hormone secretion and the cellular interactions, this system can be described as coupled oscillators. In particular, we used the Landau-Stuart model to consider both amplitudes and phases of hormone oscillations. We found that the presence of the third component, δ cell, was effective to resist under glucose perturbations, and to quickly return to the normal glucose level once perturbed. Our analysis suggested that three components are necessary for advanced homeostasis control.

  12. cPLA2alpha-evoked formation of arachidonic acid and lysophospholipids is required for exocytosis in mouse pancreatic beta-cells

    DEFF Research Database (Denmark)

    Juhl, Kirstine; Høy, Marianne; Olsen, Hervør L

    2003-01-01

    Using capacitance measurements, we investigated the effects of intracellularly applied recombinant human cytosolic phospholipase A2 (cPLA2alpha) and its lipolytic products arachidonic acid and lysophosphatidylcholine on Ca2+-dependent exocytosis in single mouse pancreatic beta-cells. cPLA2alpha...... from 70-80 to 280-300. cPLA2alpha-stimulated exocytosis was antagonized by the specific cPLA2 inhibitor AACOCF3. Ca2+-evoked exocytosis was reduced by 40% in cells treated with AACOCF3 or an antisense oligonucleotide against cPLA2alpha. The action of cPLA2alpha was mimicked by a combination...... of arachidonic acid and lysophosphatidylcholine (470% stimulation) in which each compound alone doubled the exocytotic response. Priming of insulin-containing secretory granules has been reported to involve Cl- uptake through ClC-3 Cl- channels. Accordingly, the stimulatory action of cPLA2alpha was inhibited...

  13. A Yin-Yang 1/miR-30a regulatory circuit modulates autophagy in pancreatic cancer cells.

    Science.gov (United States)

    Yang, Chuang; Zhang, Jing-Jing; Peng, Yun-Peng; Zhu, Yi; Yin, Ling-Di; Wei, Ji-Shu; Gao, Wen-Tao; Jiang, Kui-Rong; Miao, Yi

    2017-10-19

    Autophagy is a highly regulated biological process that mediates the degradation of intracellular components. It is required for tumor cell metabolism and homeostasis. Yin-Yang 1 (YY1) has been reported to be involved in autophagy in several carcinomas. However, its role in autophagy in pancreatic cancer, one of the deadliest human malignancies, is unknown. Here, we investigated the function of YY1 in pancreatic cancer cells autophagy and its mechanisms of action. The activity of cells undergoing autophagy was assessed using transmission electron microscopy, immunofluorescence, and Western blotting. A luciferase activity assay, real-time quantitative polymerase chain reaction (RT-qPCR), and chromatin immunoprecipitation (ChIP) were also used to identify putative downstream targets of YY1. YY1 was confirmed to regulate autophagy in pancreatic cancer cells. It was found to directly regulate the expression of miR-30a, a known modulator of autophagy-associated genes. Furthermore, overexpression of miR-30a attenuated the pro-autophagic effects of YY1. Cumulatively, our data suggest that miR-30a acts in a feedback loop to modulate the pro-autophagic activities of YY1. Thus, autophagy in pancreatic cancer cells may be regulated, in part, by a tightly coordinated YY1/miR-30a regulatory circuit. These findings provide a potential druggable target for the development of treatments for pancreatic cancer.

  14. Beta1 integrin-mediated adhesion signalling is essential for epidermal progenitor cell expansion

    DEFF Research Database (Denmark)

    Piwko-Czuchra, Aleksandra; Koegel, Heidi; Meyer, Hannelore

    2009-01-01

    BACKGROUND: There is a major discrepancy between the in vitro and in vivo results regarding the role of beta1 integrins in the maintenance of epidermal stem/progenitor cells. Studies of mice with skin-specific ablation of beta1 integrins suggested that epidermis can form and be maintained in thei...... of increased keratinocyte proliferation such as wound healing. CONCLUSIONS/SIGNIFICANCE: These data demonstrate that expression of beta1 integrins is critically important for the expansion of epidermal progenitor cells to maintain epidermal homeostasis....... that developed similar, but less severe defects than mice with beta1-deficient keratinocytes. Surprisingly we found that upon aging these abnormalities attenuated due to a rapid expansion of cells, which escaped or compensated for the down-regulation of beta1 integrin expression. A similar phenomenon...... was observed in aged mice with a complete, skin-specific ablation of the beta1 integrin gene, where cells that escaped Cre-mediated recombination repopulated the mutant skin in a very short time period. The expansion of beta1 integrin expressing keratinocytes was even further accelerated in situations...

  15. Human beta-cell precursors mature into functional insulin-producing cells in an immunoisolation device: implications for diabetes cell therapies.

    Science.gov (United States)

    Lee, Seung-Hee; Hao, Ergeng; Savinov, Alexei Y; Geron, Ifat; Strongin, Alex Y; Itkin-Ansari, Pamela

    2009-04-15

    Islet transplantation is limited by the need for chronic immunosuppression and the paucity of donor tissue. As new sources of human beta-cells are developed (e.g., stem cell-derived tissue), transplanting them in a durable device could obviate the need for immunosuppression, while also protecting the patient from any risk of tumorigenicity. Here, we studied (1) the survival and function of encapsulated human beta-cells and their progenitors and (2) the engraftment of encapsulated murine beta-cells in allo- and autoimmune settings. Human islets and human fetal pancreatic islet-like cell clusters were encapsulated in polytetrafluorethylene devices (TheraCyte) and transplanted into immunodeficient mice. Graft survival and function was measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets. Encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to ameliorate hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term allograft survival. Further, in the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary beta-cells ameliorated diabetes without stimulating a detectable T-cell response. We demonstrate for the first time that human beta-cells function is compatible with encapsulation in a durable, immunoprotective device. Moreover, our study suggests that encapsulation of beta-cells before terminal differentiation will be a successful approach for new cell-based therapies for diabetes, such as those derived from stem cells.

  16. Dendritic Cells Promote Pancreatic Viability in Mice with Acute Pancreatitis

    Science.gov (United States)

    Bedrosian, Andrea S.; Nguyen, Andrew H.; Hackman, Michael; Connolly, Michael K.; Malhotra, Ashim; Ibrahim, Junaid; Cieza-Rubio, Napoleon E.; Henning, Justin R.; Barilla, Rocky; Rehman, Adeel; Pachter, H. Leon; Medina-Zea, Marco V.; Cohen, Steven M.; Frey, Alan B.; Acehan, Devrim; Miller, George

    2011-01-01

    Background & Aims Acute pancreatitis increases morbidity and mortality from organ necrosis by mechanisms that are incompletely understood. Dendritic cells (DCs) can promote or suppress inflammation, depending on their subtype and context. We investigated the roles of DC in development of acute pancreatitis. Methods Acute pancreatitis was induced in CD11c.DTR mice using caerulein or L-arginine; DCs were depleted by administration of diphtheria toxin. Survival was analyzed using Kaplan-Meier analysis. Results Numbers of MHC II+CD11c+DC increased 100-fold in pancreas of mice with acute pancreatitis, to account for nearly 15% of intra-pancreatic leukocytes. Intra-pancreatic DC acquired an immune phenotype in mice with acute pancreatitis; they expressed higher levels of MHC II and CD86 and increased production of interleukin-6, membrane cofactor protein (MCP)-1, and tumor necrosis factor (TNF)-α. However, rather than inducing an organ-destructive inflammatory process, DC were required for pancreatic viability; the exocrine pancreas died in mice that were depleted of DC and challenged with caerulein or L-arginine. All mice with pancreatitis that were depleted of DC died from acinar cell death within 4 days. Depletion of DC from mice with pancreatitis resulted in neutrophil infiltration and increased levels of systemic markers of inflammation. However, the organ necrosis associated with depletion of DC did not require infiltrating neutrophils, activation of NF-κB, or signaling by mitogen-activated protein kinase or TNF-α. Conclusions DC are required for pancreatic viability in mice with acute pancreatitis and might protect organs against cell stress. PMID:21801698

  17. Bone morphogenetic protein 4 inhibits insulin secretion from rodent beta cells through regulation of calbindin1 expression and reduced voltage-dependent calcium currents

    DEFF Research Database (Denmark)

    Christensen, Gitte L.; Jacobsen, Maria L. B.; Wendt, Anna

    2015-01-01

    AIMS/HYPOTHESIS: Type 2 diabetes is characterised by progressive loss of pancreatic beta cell mass and function. Therefore, it is of therapeutic interest to identify factors with the potential to improve beta cell proliferation and insulin secretion. Bone morphogenetic protein 4 (BMP4) expression...

  18. Pancreatic effect of andrographolide isolated from Andrographis paniculata (Burm. f.) Nees.

    Science.gov (United States)

    Nugroho, Agung Endro; Rais, Ichwan Ridwan; Setiawan, Iwan; Pratiwi, Pramita Yuli; Hadibarata, Tony; Tegar, Maulana; Pramono, Suwidjiyo

    2014-01-01

    Andrographis paniculata (Burm. f.) Nees is a plant that originates from India and grows widely to Southeast which used for several purposes mainly as treatment of diabetes mellitus so the aim of this study was evaluate andrographolide for its pancreatic effect in neonatal streptozotocin (STZ)-induced diabetic rats, a model of type 2 diabetic rats. Diabetic condition was induced with an intraperitoneal injection of 90 mg kg(-1) streptozotocin in two-day-old rats. After three months, the neonatal STZ-induced diabetic rats were treated with andrographolide or andrographolide-enriched extract of A. paniculata (AEEAP) for 8 consecutive days. Pancreatic effect was evaluated by estimating mainly the preprandial and postprandial blood glucose levels and other parameters such as morphology of pancreatic islet, beta cells density and morphology and immunohistochemically pancreatic insulin. Andrographolide significantly (p < 0.05) decreased the levels of blood glucose and improved diabetic rat islet and beta cells. However, AEEAP exhibited moderate hypoglycaemic effects on the blood glucose levels. Moderate changes in beta cells were observed after AEEAP treatment. They could restore decreasing of pancreatic insulin contents. Based on these results andrographolide and AEEAP exhibited pancreatic actions in neonatal STZ-induced diabetic rats. The activity of andrographolide was more effective than this of AEEAP.

  19. Zinc as a paracrine effector in pancreatic islet cell death.

    Science.gov (United States)

    Kim, B J; Kim, Y H; Kim, S; Kim, J W; Koh, J Y; Oh, S H; Lee, M K; Kim, K W; Lee, M S

    2000-03-01

    Because of a huge amount of Zn2+ in secretory granules of pancreatic islet beta-cells, Zn2+ released in certain conditions might affect the function or survival of islet cells. We studied potential paracrine effects of endogenous Zn2+ on beta-cell death. Zn2+ induced insulinoma/islet cell death in a dose-dependent manner. Chelation of released endogenous Zn2+ by CaEDTA significantly decreased streptozotocin (STZ)-induced islet cell death in an in vitro culture system simulating in vivo circumstances but not in the conventional culture system. Zn2+ chelation in vivo by continuous CaEDTA infusion significantly decreased the incidence of diabetes after STZ administration. N-(6-methoxy-quinolyl)-para-toluene-sulfonamide staining revealed that Zn2+ was densely deposited in degenerating islet cells 24 h after STZ treatment, which was decreased by CaEDTA infusion. We show here that Zn2+ is not a passive element for insulin storage but an active participant in islet cell death in certain conditions, which in time might contribute to the development of diabetes in aged people.

  20. Effect of long-term transfusion therapy on the glycometabolic status and pancreatic beta cell function in patients with beta Thalassemia major

    Directory of Open Access Journals (Sweden)

    Kamalakshi G Bhat

    2014-01-01

    Full Text Available Background: Diabetes mellitus is a major complication of iron overload in patients with beta thalassemia major. Design: This is a descriptive study conducted in a Tertiary Care Teaching Hospital to analyze beta cell function and insulin resistance, and their relation to iron overload status in beta thalassemia major. Fasting glucose, two-hour post load glucose, fasting insulin, alanine amino transaminase (ALT, and ferritin were used as outcome measures. The homeostatic model assessment (HOMA model was used to calculate the beta cell function and insulin resistance index. Results: Of the 30 cases, 20% had impaired fasting glucose, 3.3% had impaired glucose tolerance, and none had diabetes. Fasting glucose was not significant between the cases and controls (P = 0.113. Fasting insulin (P = 0.001, ferritin (P = 0.001, and ALT (P = 0.001 levels were significantly high in the cases. Insulin resistance index was significantly higher in the cases (P = 0.001 as also the beta cell function (P = 0.001. With increase in age and the number of units transfused there is a decline in beta cell function, fasting insulin, and insulin resistance after attaining the maximum level. This suggests that initial insulin resistance is followed by insulin depletion due to loss of beta cell function, leading to diabetes mellitus. Conclusion: Impaired glucose tolerance (IGT and insulin resistance precede the onset of insulin-dependent diabetes and adequate chelation therapy is essential for delaying the onset or for prevention of diabetes.

  1. Pancreatic adenocarcinoma, chronic pancreatitis, and MODY-8 diabetes: is bile salt-dependent lipase (or carboxyl ester lipase) at the crossroads of pancreatic pathologies?

    Science.gov (United States)

    Lombardo, Dominique; Silvy, Françoise; Crenon, Isabelle; Martinez, Emmanuelle; Collignon, Aurélie; Beraud, Evelyne; Mas, Eric

    2018-02-23

    Pancreatic adenocarcinomas and diabetes mellitus are responsible for the deaths of around two million people each year worldwide. Patients with chronic pancreatitis do not die directly of this disease, except where the pathology is hereditary. Much current literature supports the involvement of bile salt-dependent lipase (BSDL), also known as carboxyl ester lipase (CEL), in the pathophysiology of these pancreatic diseases. The purpose of this review is to shed light on connections between chronic pancreatitis, diabetes, and pancreatic adenocarcinomas by gaining an insight into BSDL and its variants. This enzyme is normally secreted by the exocrine pancreas, and is diverted within the intestinal lumen to participate in the hydrolysis of dietary lipids. However, BSDL is also expressed by other cells and tissues, where it participates in lipid homeostasis. Variants of BSDL resulting from germline and/or somatic mutations (nucleotide insertion/deletion or nonallelic homologous recombination) are expressed in the pancreas of patients with pancreatic pathologies such as chronic pancreatitis, MODY-8, and pancreatic adenocarcinomas. We discuss the possible link between the expression of BSDL variants and these dramatic pancreatic pathologies, putting forward the suggestion that BSDL and its variants are implicated in the cell lipid metabolism/reprogramming that leads to the dyslipidemia observed in chronic pancreatitis, MODY-8, and pancreatic adenocarcinomas. We also propose potential strategies for translation to therapeutic applications.

  2. Role of pancreatic polypeptide as a market of transplanted insulin-producing fetal pig cells.

    Science.gov (United States)

    Tuch, B E; Tabiin, M T; Casamento, F M; Yao, M; Georges, P; Amaratunga, A; Pinto, A N

    2001-01-01

    Transplantation of insulin-producing fetal pancreatic tissue into diabetic recipients has been shown to normalize blood glucose levels after several months. This time period is required for the growth and maturation of the fetal tissue so insulin levels cannot be used as a marker of graft function while the beta-cell is immature. Therefore, we have examined the use of another pancreatic endocrine hormone, pancreatic polypeptide (PP), to monitor graft function. The cell that produces this hormone has been shown to be the first mature endocrine cell in the fetal pancreas. Fetal pig pancreatic tissue, both in the form of 1 mm3 explants and islet-like cell clusters (ICCs), was transplanted into immunodeficient SCID mice and the levels of PP and insulin were measured in plasma and in the graft for up to 12 weeks. PP was detected in the untransplanted explants (0.58 pmol/mg) and ICCs (0.06 pmol/ICC) and the PP to insulin ratio was 2.7% and 5.8%, respectively. PP (but not porcine C-peptide, a marker of insulin secretion) was detectable in the plasma of SCID mice from 4 days to 3 weeks after transplantation, but not thereafter. The highest values were obtained at 4 days to 1 week. In the grafted tissue PP and insulin were present at all time points and the ratio of PP to insulin was 59%, 87%, 75%, 56%, 7%, 8%, and 7% at 4 days, 1, 2, 3, 6, 9, and 12 weeks, respectively. The decline in PP levels 3 weeks after transplantation was associated with beta-cell development in the graft. PP was also secreted by fetal pig pancreatic explants transplanted into diabetic NOD/SCID mice, with plasma levels measurable in the first week after the tissue was grafted. In immunocompetent BALB/c mice transplanted with the tissue, PP was detectable in plasma for 2 days after transplantation but not at 4 days, when cellular rejection commenced, or thereafter. We conclude that plasma PP levels can be used as a marker of the viability of fetal porcine pancreatic tissue in the first 3 weeks after

  3. Dclk1 Defines Quiescent Pancreatic Progenitors that Promote Injury-Induced Regeneration and Tumorigenesis | Office of Cancer Genomics

    Science.gov (United States)

    The existence of adult pancreatic progenitor cells has been debated. While some favor the concept of facultative progenitors involved in homeostasis and repair, neither a location nor markers for such cells have been defined. Using genetic lineage tracing, we show that Doublecortin-like kinase-1 (Dclk1) labels a rare population of long-lived, quiescent pancreatic cells. In vitro, Dclk1+ cells proliferate readily and sustain pancreatic organoid growth. In vivo, Dclk1+ cells are necessary for pancreatic regeneration following injury and chronic inflammation.

  4. An Abbreviated Protocol for In Vitro Generation of Functional Human Embryonic Stem Cell-Derived Beta-Like Cells

    DEFF Research Database (Denmark)

    Massumi, Mohammad; Pourasgari, Farzaneh; Nalla, Amarnadh

    2016-01-01

    developed an abbreviated five-stage protocol (25-30 days) to generate human Embryonic Stem Cell-Derived Beta-like Cells (ES-DBCs). We showed that Geltrex, as an extracellular matrix, could support the generation of ES-DBCs more efficiently than that of the previously described culture systems......The ability to yield glucose-responsive pancreatic beta-cells from human pluripotent stem cells in vitro will facilitate the development of the cell replacement therapies for the treatment of Type 1 Diabetes. Here, through the sequential in vitro targeting of selected signaling pathways, we have...... positive cells, 1% insulin and glucagon positive cells and 30% insulin and NKX6.1 co-expressing cells. Functionally, ES-DBCs were responsive to high glucose in static incubation and perifusion studies, and could secrete insulin in response to successive glucose stimulations. Mitochondrial metabolic flux...

  5. Inflammatory stress of pancreatic beta cells drives release of extracellular heat-shock protein 90α.

    Science.gov (United States)

    Ocaña, Gail J; Pérez, Liliana; Guindon, Lynette; Deffit, Sarah N; Evans-Molina, Carmella; Thurmond, Debbie C; Blum, Janice S

    2017-06-01

    A major obstacle in predicting and preventing the development of autoimmune type 1 diabetes (T1D) in at-risk individuals is the lack of well-established early biomarkers indicative of ongoing beta cell stress during the pre-clinical phase of disease. Recently, serum levels of the α cytoplasmic isoform of heat-shock protein 90 (hsp90) were shown to be elevated in individuals with new-onset T1D. We therefore hypothesized that hsp90α could be released from beta cells in response to cellular stress and inflammation associated with the earliest stages of T1D. Here, human beta cell lines and cadaveric islets released hsp90α in response to stress induced by treatment with a combination of pro-inflammatory cytokines including interleukin-1β, tumour necrosis factor-α and interferon-γ. Mechanistically, hsp90α release was found to be driven by cytokine-induced endoplasmic reticulum stress mediated by c-Jun N-terminal kinase (JNK), a pathway that can eventually lead to beta cell apoptosis. Cytokine-induced beta cell hsp90α release and JNK activation were significantly reduced by pre-treating cells with the endoplasmic reticulum stress-mitigating chemical chaperone tauroursodeoxycholic acid. The hsp90α release by cells may therefore be a sensitive indicator of stress during inflammation and a useful tool in assessing therapeutic mitigation of cytokine-induced cell damage linked to autoimmunity. © 2017 John Wiley & Sons Ltd.

  6. Sodium arsenite impairs insulin secretion and transcription in pancreatic β-cells

    International Nuclear Information System (INIS)

    Diaz-Villasenor, Andrea; Sanchez-Soto, M. Carmen; Cebrian, Mariano E.; Ostrosky-Wegman, Patricia; Hiriart, Marcia

    2006-01-01

    Human studies have shown that chronic inorganic arsenic (iAs) exposure is associated with a high prevalence and incidence of type 2 diabetes. However, the mechanism(s) underlying this effect are not well understood, and practically, there is no information available on the effects of arsenic on pancreatic β-cells functions. Thus, since insulin secreted by the pancreas plays a crucial role in maintaining glucose homeostasis, our aim was to determine if sodium arsenite impairs insulin secretion and mRNA expression in single adult rat pancreatic β-cells. Cells were treated with 0.5, 1, 2, 5 and 10 μM sodium arsenite and incubated for 72 and 144 h. The highest dose tested (10 μM) decreased β-cell viability, by 33% and 83%, respectively. Insulin secretion and mRNA expression were evaluated in the presence of 1 and 5 μM sodium arsenite. Basal insulin secretion, in 5.6 mM glucose, was not significantly affected by 1 or 5 μM treatment for 72 h, but basal secretion was reduced when cells were exposed to 5 μM sodium arsenite for 144 h. On the other hand, insulin secretion in response to 15.6 mM glucose decreased with sodium arsenite in a dose-dependent manner in such a way that cells were no longer able to distinguish between different glucose concentrations. We also showed a significant decrease in insulin mRNA expression of cells exposed to 5 μM sodium arsenite during 72 h. Our data suggest that arsenic may contribute to the development of diabetes mellitus by impairing pancreatic β-cell functions, particularly insulin synthesis and secretion

  7. The role of polyunsaturated fatty acids (n-3 PUFAs) on the pancreatic β-cells and insulin action.

    Science.gov (United States)

    Baynes, Habtamu Wondifraw; Mideksa, Seifu; Ambachew, Sintayehu

    2018-03-14

    Polyunsaturated Fatty acids have multiple effects in peripheral tissues and pancreatic beta cell function. The n-3 Polyunsaturated Fatty acids prevent and reverse high-fat-diet induced adipose tissue inflammation and insulin resistance. Insulin secretion is stimulated by glucose, amino acids, and glucagon- like peptide-1 in tissue containing high levels of n-3 Polyunsaturated Fatty acids than lower level of n-3 Polyunsaturated Fatty acids. Also, n-3 Polyunsaturated Fatty acids led to decreased production of prostaglandin, which in turn contributed to the elevation of insulin secretion. N-3 polyunsaturated fatty acids prevent cytokine-induced cell death in pancreatic islets. Supplementation of n-3 Polyunsaturated Fatty acids for human subjects prevent beta cell destruction and insulin resistance. It also enhances insulin secretion, reduction in lipid profiles and glucose concentration particularly in type II diabetes patients. Therefore there should be a focus on the treatment mechanism of insulin related obesity and diabetes by n-3 polyunsaturated fatty acids.

  8. B cell depletion reduces T cell activation in pancreatic islets in a murine autoimmune diabetes model.

    Science.gov (United States)

    Da Rosa, Larissa C; Boldison, Joanne; De Leenheer, Evy; Davies, Joanne; Wen, Li; Wong, F Susan

    2018-06-01

    Type 1 diabetes is a T cell-mediated autoimmune disease characterised by the destruction of beta cells in the islets of Langerhans, resulting in deficient insulin production. B cell depletion therapy has proved successful in preventing diabetes and restoring euglycaemia in animal models of diabetes, as well as in preserving beta cell function in clinical trials in the short term. We aimed to report a full characterisation of B cell kinetics post B cell depletion, with a focus on pancreatic islets. Transgenic NOD mice with a human CD20 transgene expressed on B cells were injected with an anti-CD20 depleting antibody. B cells were analysed using multivariable flow cytometry. There was a 10 week delay in the onset of diabetes when comparing control and experimental groups, although the final difference in the diabetes incidence, following prolonged observation, was not statistically significant (p = 0.07). The co-stimulatory molecules CD80 and CD86 were reduced on stimulation of B cells during B cell depletion and repopulation. IL-10-producing regulatory B cells were not induced in repopulated B cells in the periphery, post anti-CD20 depletion. However, the early depletion of B cells had a marked effect on T cells in the local islet infiltrate. We demonstrated a lack of T cell activation, specifically with reduced CD44 expression and effector function, including IFN-γ production from both CD4 + and CD8 + T cells. These CD8 + T cells remained altered in the pancreatic islets long after B cell depletion and repopulation. Our findings suggest that B cell depletion can have an impact on T cell regulation, inducing a durable effect that is present long after repopulation. We suggest that this local effect of reducing autoimmune T cell activity contributes to delay in the onset of autoimmune diabetes.

  9. Assessment of Toxicological Perturbations and Variants of Pancreatic Islet Development in the Zebrafish Model

    Directory of Open Access Journals (Sweden)

    Karilyn E. Sant

    2016-09-01

    Full Text Available The pancreatic islets, largely comprised of insulin-producing beta cells, play a critical role in endocrine signaling and glucose homeostasis. Because they have low levels of antioxidant defenses and a high perfusion rate, the endocrine islets may be a highly susceptible target tissue of chemical exposures. However, this endpoint, as well as the integrity of the surrounding exocrine pancreas, is often overlooked in studies of developmental toxicology. Disruption of development by toxicants can alter cell fate and migration, resulting in structural alterations that are difficult to detect in mammalian embryo systems, but that are easily observed in the zebrafish embryo model (Danio rerio. Using endogenously expressed fluorescent protein markers for developing zebrafish beta cells and exocrine pancreas tissue, we documented differences in islet area and incidence rates of islet morphological variants in zebrafish embryos between 48 and 96 h post fertilization (hpf, raised under control conditions commonly used in embryotoxicity assays. We identified critical windows for chemical exposures during which increased incidences of endocrine pancreas abnormalities were observed following exposure to cyclopamine (2–12 hpf, Mono-2-ethylhexyl phthalate (MEHP (3–48 hpf, and Perfluorooctanesulfonic acid (PFOS (3–48 hpf. Both islet area and length of the exocrine pancreas were sensitive to oxidative stress from exposure to the oxidant tert-butyl hydroperoxide during a highly proliferative critical window (72 hpf. Finally, pancreatic dysmorphogenesis following developmental exposures is discussed with respect to human disease.

  10. Rac1-NADPH oxidase signaling promotes CD36 activation under glucotoxic conditions in pancreatic beta cells.

    Science.gov (United States)

    Elumalai, Suma; Karunakaran, Udayakumar; Lee, In Kyu; Moon, Jun Sung; Won, Kyu Chang

    2017-04-01

    We recently reported that cluster determinant 36 (CD36), a fatty acid transporter, plays a pivotal role in glucotoxicity-induced β-cell dysfunction. However, little is known about how glucotoxicity influences CD36 expression. Emerging evidence suggests that the small GTPase Rac1 is involved in the pathogenesis of beta cell dysfunction in type 2 diabetes (T2D). The primary objective of the current study was to determine the role of Rac1 in CD36 activation and its impact on β-cell dysfunction in diabetes mellitus. To address this question, we subjected INS-1 cells and human beta cells (1.1B4) to high glucose conditions (30mM) in the presence or absence of Rac1 inhibition either by NSC23766 (Rac1 GTPase inhibitor) or small interfering RNA. High glucose exposure in INS-1 and human beta cells (1.1b4) resulted in the activation of Rac1 and induced cell apoptosis. Rac1 activation mediates NADPH oxidase (NOX) activation leading to elevated ROS production in both cells. Activation of the Rac1-NOX complex by high glucose levels enhanced CD36 expression in INS-1 and human 1.1b4 beta cell membrane fractions. The inhibition of Rac1 by NSC23766 inhibited NADPH oxidase activity and ROS generation induced by high glucose concentrations in INS-1 & human 1.1b4 beta cells. Inhibition of Rac1-NOX complex activation by NSC23766 significantly reduced CD36 expression in INS-1 and human 1.1b4 beta cell membrane fractions. In addition, Rac1 inhibition by NSC23766 significantly reduced high glucose-induced mitochondrial dysfunction. Furthermore, NADPH oxidase inhibition by VAS2870 also attenuated high glucose-induced ROS generation and cell apoptosis. These results suggest that Rac1-NADPH oxidase dependent CD36 expression contributes to high glucose-induced beta cell dysfunction and cell death. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  11. A human beta cell line with drug inducible excision of immortalizing transgenes

    Science.gov (United States)

    Benazra, Marion; Lecomte, Marie-José; Colace, Claire; Müller, Andreas; Machado, Cécile; Pechberty, Severine; Bricout-Neveu, Emilie; Grenier-Godard, Maud; Solimena, Michele; Scharfmann, Raphaël; Czernichow, Paul; Ravassard, Philippe

    2015-01-01

    Objectives Access to immortalized human pancreatic beta cell lines that are phenotypically close to genuine adult beta cells, represent a major tool to better understand human beta cell physiology and develop new therapeutics for Diabetes. Here we derived a new conditionally immortalized human beta cell line, EndoC-βH3 in which immortalizing transgene can be efficiently removed by simple addition of tamoxifen. Methods We used lentiviral mediated gene transfer to stably integrate a tamoxifen inducible form of CRE (CRE-ERT2) into the recently developed conditionally immortalized EndoC βH2 line. The resulting EndoC-βH3 line was characterized before and after tamoxifen treatment for cell proliferation, insulin content and insulin secretion. Results We showed that EndoC-βH3 expressing CRE-ERT2 can be massively amplified in culture. We established an optimized tamoxifen treatment to efficiently excise the immortalizing transgenes resulting in proliferation arrest. In addition, insulin expression raised by 12 fold and insulin content increased by 23 fold reaching 2 μg of insulin per million cells. Such massive increase was accompanied by enhanced insulin secretion upon glucose stimulation. We further observed that tamoxifen treated cells maintained a stable function for 5 weeks in culture. Conclusions EndoC βH3 cell line represents a powerful tool that allows, using a simple and efficient procedure, the massive production of functional non-proliferative human beta cells. Such cells are close to genuine human beta cells and maintain a stable phenotype for 5 weeks in culture. PMID:26909308

  12. Free fatty acid receptors act as nutrient sensors to regulate energy homeostasis.

    Science.gov (United States)

    Ichimura, Atsuhiko; Hirasawa, Akira; Hara, Takafumi; Tsujimoto, Gozoh

    2009-09-01

    Free fatty acids (FFAs) have been demonstrated to act as ligands of several G-protein-coupled receptors (GPCRs) (FFAR1, FFAR2, FFAR3, GPR84, and GPR120). These fatty acid receptors are proposed to play critical roles in a variety of types of physiological homeostasis. FFAR1 and GPR120 are activated by medium- and long-chain FFAs. GPR84 is activated by medium-chain, but not long-chain, FFAs. In contrast, FFAR2 and FFAR3 are activated by short-chain FFAs. FFAR1 is expressed mainly in pancreatic beta-cells and mediates insulin secretion, whereas GPR120 is expressed abundantly in the intestine and promotes the secretion of glucagon-like peptide-1 (GLP-1). FFAR3 is expressed in enteroendocrine cells and regulates host energy balance through effects that are dependent upon the gut microbiota. In this review, we summarize the identification, structure, and pharmacology of these receptors and present an essential overview of the current understanding of their physiological roles.

  13. COPII-Dependent ER Export: A Critical Component of Insulin Biogenesis and β-Cell ER Homeostasis.

    Science.gov (United States)

    Fang, Jingye; Liu, Ming; Zhang, Xuebao; Sakamoto, Takeshi; Taatjes, Douglas J; Jena, Bhanu P; Sun, Fei; Woods, James; Bryson, Tim; Kowluru, Anjaneyulu; Zhang, Kezhong; Chen, Xuequn

    2015-08-01

    Pancreatic β-cells possess a highly active protein synthetic and export machinery in the endoplasmic reticulum (ER) to accommodate the massive production of proinsulin. ER homeostasis is vital for β-cell functions and is maintained by the delicate balance between protein synthesis, folding, export, and degradation. Disruption of ER homeostasis by diabetes-causing factors leads to β-cell death. Among the 4 components to maintain ER homeostasis in β-cells, the role of ER export in insulin biogenesis is the least understood. To address this knowledge gap, the present study investigated the molecular mechanism of proinsulin ER export in MIN6 cells and primary islets. Two inhibitory mutants of the secretion-associated RAS-related protein (Sar)1 small GTPase, known to specifically block coat protein complex II (COPII)-dependent ER export, were overexpressed in β-cells using recombinant adenoviruses. Results from this approach, as well as small interfering RNA-mediated Sar1 knockdown, demonstrated that defective Sar1 function blocked proinsulin ER export and abolished its conversion to mature insulin in MIN6 cells, isolated mouse, and human islets. It is further revealed, using an in vitro vesicle formation assay, that proinsulin was packaged into COPII vesicles in a GTP- and Sar1-dependent manner. Blockage of COPII-dependent ER exit by Sar1 mutants strongly induced ER morphology change, ER stress response, and β-cell apoptosis. These responses were mediated by the PKR (double-stranded RNA-dependent kinase)-like ER kinase (PERK)/eukaryotic translation initiation factor 2α (p-eIF2α) and inositol-requiring protein 1 (IRE1)/x-box binding protein 1 (Xbp1) pathways but not via activating transcription factor 6 (ATF6). Collectively, results from the study demonstrate that COPII-dependent ER export plays a vital role in insulin biogenesis, ER homeostasis, and β-cell survival.

  14. LGR5 and Nanog identify stem cell signature of pancreas beta cells which initiate pancreatic cancer.

    Science.gov (United States)

    Amsterdam, Abraham; Raanan, Calanit; Schreiber, Letizia; Polin, Nava; Givol, David

    2013-04-05

    Pancreas cancer, is the fourth leading cause of cancer death but its cell of origin is controversial. We compared the localization of stem cells in normal and cancerous pancreas using antibodies to the stem cell markers Nanog and LGR5. Here we show, for the first time, that LGR5 is expressed in normal pancreas, exclusively in the islets of Langerhans and it is co-localized, surprisingly, with Nanog and insulin in clusters of beta cells. In cancerous pancreas Nanog and LGR5 are expressed in the remaining islets and in all ductal cancer cells. We observed insulin staining among the ductal cancer cells, but not in metastases. This indicates that the islet's beta cells, expressing LGR5 and Nanog markers are the initiating cells of pancreas cancer, which migrated from the islets to form the ductal cancerous tissue, probably after mutation and de-differentiation. This discovery may facilitate treatment of this devastating cancer. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Developmental programming of polycystic ovary syndrome (PCOS): prenatal androgens establish pancreatic islet α/β cell ratio and subsequent insulin secretion.

    Science.gov (United States)

    Ramaswamy, S; Grace, C; Mattei, A A; Siemienowicz, K; Brownlee, W; MacCallum, J; McNeilly, A S; Duncan, W C; Rae, M T

    2016-06-06

    Exogenous androgenic steroids applied to pregnant sheep programmes a PCOS-like phenotype in female offspring. Via ultrasound guidance we applied steroids directly to ovine fetuses at d62 and d82 of gestation, and examined fetal (day 90 gestation) and postnatal (11 months old) pancreatic structure and function. Of three classes of steroid agonists applied (androgen - Testosterone propionate (TP), estrogen - Diethystilbesterol (DES) and glucocorticoid - Dexamethasone (DEX)), only androgens (TP) caused altered pancreatic development. Beta cell numbers were significantly elevated in prenatally androgenised female fetuses (P = 0.03) (to approximately the higher numbers found in male fetuses), whereas alpha cell counts were unaffected, precipitating decreased alpha:beta cell ratios in the developing fetal pancreas (P = 0.001), sustained into adolescence (P = 0.0004). In adolescence basal insulin secretion was significantly higher in female offspring from androgen-excess pregnancies (P = 0.045), and an exaggerated, hyperinsulinaemic response to glucose challenge (P = 0.0007) observed, whereas prenatal DES or DEX treatment had no effects upon insulin secretion. Postnatal insulin secretion correlated with beta cell numbers (P = 0.03). We conclude that the pancreas is a primary locus of androgenic stimulation during development, giving rise to postnatal offspring whose pancreas secreted excess insulin due to excess beta cells in the presence of a normal number of alpha cells.

  16. Lysine deacetylases are produced in pancreatic beta cells and are differentially regulated by proinflammatory cytokines

    DEFF Research Database (Denmark)

    Lundh, M; Christensen, D P; Rasmussen, D N

    2010-01-01

    Cytokine-induced beta cell toxicity is abrogated by non-selective inhibitors of lysine deacetylases (KDACs). The KDAC family consists of 11 members, namely histone deacetylases HDAC1 to HDAC11, but it is not known which KDAC members play a role in cytokine-mediated beta cell death. The aim...

  17. Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

    International Nuclear Information System (INIS)

    Lubaczeuski, C.; Balbo, S.L.; Ribeiro, R.A.; Vettorazzi, J.F.; Santos-Silva, J.C.; Carneiro, E.M.; Bonfleur, M.L.

    2015-01-01

    The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca 2+ mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca 2+ mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats

  18. Simultaneous characterization of pancreatic stellate cells and other pancreatic components within three-dimensional tissue environment during chronic pancreatitis

    Science.gov (United States)

    Hu, Wenyan; Fu, Ling

    2013-05-01

    Pancreatic stellate cells (PSCs) and other pancreatic components that play a critical role in exocrine pancreatic diseases are generally identified separately by conventional studies, which provide indirect links between these components. Here, nonlinear optical microscopy was evaluated for simultaneous characterization of these components within a three-dimensional (3-D) tissue environment, primarily based on multichannel detection of intrinsic optical emissions and cell morphology. Fresh rat pancreatic tissues harvested at 1 day, 7 days, and 28 days after induction of chronic pancreatitis were imaged, respectively. PSCs, inflammatory cells, blood vessels, and collagen fibers were identified simultaneously. The PSCs at day 1 of chronic pancreatitis showed significant enlargement compared with those in normal pancreas (ppancreatic components coincidently within 3-D pancreatic tissues. It is a prospect for intravital observation of dynamic events under natural physiological conditions, and might help uncover the key mechanisms of exocrine pancreatic diseases, leading to more effective treatments.

  19. Pancreatic Islet Cell Transplantation

    Science.gov (United States)

    Warnock, Garth L.; Rajotte, Ray V.

    1992-01-01

    Transplantation of insulin-producing tissue offers a physiologic approach to restoration of glycemic control. Whereas transplantation of vascularized pancreatic grafts has recently achieved encouraging results, pancreatic islet cell transplantation holds the promise of low morbidity and reduced requirements for agressive immunosuppression for recipients. Islet cell transplantation was recently demonstrated to induce euglycemia with insulin independence. Imagesp1656-a PMID:21221366

  20. Palmitate activates autophagy in INS-1E β-cells and in isolated rat and human pancreatic islets.

    Directory of Open Access Journals (Sweden)

    Luisa Martino

    Full Text Available We have investigated the in vitro effects of increased levels of glucose and free fatty acids on autophagy activation in pancreatic beta cells. INS-1E cells and isolated rat and human pancreatic islets were incubated for various times (from 2 to 24 h at different concentrations of glucose and/or palmitic acid. Then, cell survival was evaluated and autophagy activation was explored by using various biochemical and morphological techniques. In INS-1E cells as well as in rat and human islets, 0.5 and 1.0 mM palmitate markedly increased autophagic vacuole formation, whereas high glucose was ineffective alone and caused little additional change when combined with palmitate. Furthermore, LC3-II immunofluorescence co-localized with that of cathepsin D, a lysosomal marker, showing that the autophagic flux was not hampered in PA-treated cells. These effects were maintained up to 18-24 h incubation and were associated with a significant decline of cell survival correlated with both palmitate concentration and incubation time. Ultrastructural analysis showed that autophagy activation, as evidenced by the occurrence of many autophagic vacuoles in the cytoplasm of beta cells, was associated with a diffuse and remarkable swelling of the endoplasmic reticulum. Our results indicate that among the metabolic alterations typically associated with type 2 diabetes, high free fatty acids levels could play a role in the activation of autophagy in beta cells, through a mechanism that might involve the induction of endoplasmic reticulum stress.

  1. Stabilization of beta-catenin induces pancreas tumor formation.

    Science.gov (United States)

    Heiser, Patrick W; Cano, David A; Landsman, Limor; Kim, Grace E; Kench, James G; Klimstra, David S; Taketo, Maketo M; Biankin, Andrew V; Hebrok, Matthias

    2008-10-01

    beta-Catenin signaling within the canonical Wnt pathway is essential for pancreas development. However, the pathway is normally down-regulated in the adult organ. Increased cytoplasmic and nuclear localization of beta-catenin can be detected in nearly all human solid pseudopapillary neoplasms (SPN), a rare tumor with low malignant potential. Conversely, pancreatic ductal adenocarcinoma (PDA) accounts for the majority of pancreatic tumors and is among the leading causes of cancer death. Whereas activating mutations within beta-catenin and other members of the canonical Wnt pathway are rare, recent reports have implicated Wnt signaling in the development and progression of human PDA. Here, we sought to address the role of beta-catenin signaling in pancreas tumorigenesis. Using Cre/lox technology, we conditionally activated beta-catenin in a subset of murine pancreatic cells in vivo. Activation of beta-catenin results in the formation of large pancreatic tumors at a high frequency in adult mice. These tumors resemble human SPN based on morphologic and immunohistochemical comparisons. Interestingly, stabilization of beta-catenin blocks the formation of pancreatic intraepithelial neoplasia (PanIN) in the presence of an activating mutation in Kras that is known to predispose individuals to PDA. Instead, mice in which beta-catenin and Kras are concurrently activated develop distinct ductal neoplasms that do not resemble PanIN lesions. These results demonstrate that activation of beta-catenin is sufficient to induce pancreas tumorigenesis. Moreover, they indicate that the sequence in which oncogenic mutations are acquired has profound consequences on the phenotype of the resulting tumor.

  2. Beta1 integrin-mediated adhesion signalling is essential for epidermal progenitor cell expansion.

    Directory of Open Access Journals (Sweden)

    Aleksandra Piwko-Czuchra

    Full Text Available BACKGROUND: There is a major discrepancy between the in vitro and in vivo results regarding the role of beta1 integrins in the maintenance of epidermal stem/progenitor cells. Studies of mice with skin-specific ablation of beta1 integrins suggested that epidermis can form and be maintained in their absence, while in vitro data have shown a fundamental role for these adhesion receptors in stem/progenitor cell expansion and differentiation. METHODOLOGY/PRINCIPAL FINDINGS: To elucidate this discrepancy we generated hypomorphic mice expressing reduced beta1 integrin levels on keratinocytes that developed similar, but less severe defects than mice with beta1-deficient keratinocytes. Surprisingly we found that upon aging these abnormalities attenuated due to a rapid expansion of cells, which escaped or compensated for the down-regulation of beta1 integrin expression. A similar phenomenon was observed in aged mice with a complete, skin-specific ablation of the beta1 integrin gene, where cells that escaped Cre-mediated recombination repopulated the mutant skin in a very short time period. The expansion of beta1 integrin expressing keratinocytes was even further accelerated in situations of increased keratinocyte proliferation such as wound healing. CONCLUSIONS/SIGNIFICANCE: These data demonstrate that expression of beta1 integrins is critically important for the expansion of epidermal progenitor cells to maintain epidermal homeostasis.

  3. Adipose tissue-derived stem cells promote pancreatic cancer cell proliferation and invasion

    International Nuclear Information System (INIS)

    Ji, S.Q.; Cao, J.; Zhang, Q.Y.; Li, Y.Y.; Yan, Y.Q.; Yu, F.X.

    2013-01-01

    To explore the effects of adipose tissue-derived stem cells (ADSCs) on the proliferation and invasion of pancreatic cancer cells in vitro and the possible mechanism involved, ADSCs were cocultured with pancreatic cancer cells, and a cell counting kit (CCK-8) was used to detect the proliferation of pancreatic cancer cells. ELISA was used to determine the concentration of stromal cell-derived factor-1 (SDF-1) in the supernatants. RT-PCR was performed to detect the expression of the chemokine receptor CXCR4 in pancreatic cancer cells and ADSCs. An in vitro invasion assay was used to measure invasion of pancreatic cancer cells. SDF-1 was detected in the supernatants of ADSCs, but not in pancreatic cancer cells. Higher CXCR4 mRNA levels were detected in the pancreatic cancer cell lines compared with ADSCs (109.3±10.7 and 97.6±7.6 vs 18.3±1.7, respectively; P<0.01). In addition, conditioned medium from ADSCs promoted the proliferation and invasion of pancreatic cancer cells, and AMD3100, a CXCR4 antagonist, significantly downregulated these growth-promoting effects. We conclude that ADSCs can promote the proliferation and invasion of pancreatic cancer cells, which may involve the SDF-1/CXCR4 axis

  4. Adipose tissue-derived stem cells promote pancreatic cancer cell proliferation and invasion

    Energy Technology Data Exchange (ETDEWEB)

    Ji, S.Q.; Cao, J. [Department of Liver Surgery I, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai (China); Zhang, Q.Y.; Li, Y.Y. [Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Wenzhou Medical College, Wenzhou (China); Yan, Y.Q. [Department of Liver Surgery I, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai (China); Yu, F.X. [Department of Hepatobiliary and Pancreatic Surgery, The First Affiliated Hospital, Wenzhou Medical College, Wenzhou (China)

    2013-09-27

    To explore the effects of adipose tissue-derived stem cells (ADSCs) on the proliferation and invasion of pancreatic cancer cells in vitro and the possible mechanism involved, ADSCs were cocultured with pancreatic cancer cells, and a cell counting kit (CCK-8) was used to detect the proliferation of pancreatic cancer cells. ELISA was used to determine the concentration of stromal cell-derived factor-1 (SDF-1) in the supernatants. RT-PCR was performed to detect the expression of the chemokine receptor CXCR4 in pancreatic cancer cells and ADSCs. An in vitro invasion assay was used to measure invasion of pancreatic cancer cells. SDF-1 was detected in the supernatants of ADSCs, but not in pancreatic cancer cells. Higher CXCR4 mRNA levels were detected in the pancreatic cancer cell lines compared with ADSCs (109.3±10.7 and 97.6±7.6 vs 18.3±1.7, respectively; P<0.01). In addition, conditioned medium from ADSCs promoted the proliferation and invasion of pancreatic cancer cells, and AMD3100, a CXCR4 antagonist, significantly downregulated these growth-promoting effects. We conclude that ADSCs can promote the proliferation and invasion of pancreatic cancer cells, which may involve the SDF-1/CXCR4 axis.

  5. Prion protein modulates glucose homeostasis by altering intracellular iron.

    Science.gov (United States)

    Ashok, Ajay; Singh, Neena

    2018-04-26

    The prion protein (PrP C ), a mainly neuronal protein, is known to modulate glucose homeostasis in mouse models. We explored the underlying mechanism in mouse models and the human pancreatic β-cell line 1.1B4. We report expression of PrP C on mouse pancreatic β-cells, where it promoted uptake of iron through divalent-metal-transporters. Accordingly, pancreatic iron stores in PrP knockout mice (PrP -/- ) were significantly lower than wild type (PrP +/+ ) controls. Silencing of PrP C in 1.1B4 cells resulted in significant depletion of intracellular (IC) iron, and remarkably, upregulation of glucose transporter GLUT2 and insulin. Iron overloading, on the other hand, resulted in downregulation of GLUT2 and insulin in a PrP C -dependent manner. Similar observations were noted in the brain, liver, and neuroretina of iron overloaded PrP +/+ but not PrP -/- mice, indicating PrP C -mediated modulation of insulin and glucose homeostasis through iron. Peripheral challenge with glucose and insulin revealed blunting of the response in iron-overloaded PrP +/+ relative to PrP -/- mice, suggesting that PrP C -mediated modulation of IC iron influences both secretion and sensitivity of peripheral organs to insulin. These observations have implications for Alzheimer's disease and diabetic retinopathy, known complications of type-2-diabetes associated with brain and ocular iron-dyshomeostasis.

  6. Pancreatic Cancer-Derived Exosomes Cause Paraneoplastic β-cell Dysfunction.

    Science.gov (United States)

    Javeed, Naureen; Sagar, Gunisha; Dutta, Shamit K; Smyrk, Thomas C; Lau, Julie S; Bhattacharya, Santanu; Truty, Mark; Petersen, Gloria M; Kaufman, Randal J; Chari, Suresh T; Mukhopadhyay, Debabrata

    2015-04-01

    Pancreatic cancer frequently causes diabetes. We recently proposed adrenomedullin as a candidate mediator of pancreatic β-cell dysfunction in pancreatic cancer. How pancreatic cancer-derived adrenomedullin reaches β cells remote from the cancer to induce β-cell dysfunction is unknown. We tested a novel hypothesis that pancreatic cancer sheds adrenomedullin-containing exosomes into circulation, which are transported to β cells and impair insulin secretion. We characterized exosomes from conditioned media of pancreatic cancer cell lines (n = 5) and portal/peripheral venous blood of patients with pancreatic cancer (n = 20). Western blot analysis showed the presence of adrenomedullin in pancreatic cancer-exosomes. We determined the effect of adrenomedullin-containing pancreatic cancer exosomes on insulin secretion from INS-1 β cells and human islets, and demonstrated the mechanism of exosome internalization into β cells. We studied the interaction between β-cell adrenomedullin receptors and adrenomedullin present in pancreatic cancer-exosomes. In addition, the effect of adrenomedullin on endoplasmic reticulum (ER) stress response genes and reactive oxygen/nitrogen species generation in β cells was shown. Exosomes were found to be the predominant extracellular vesicles secreted by pancreatic cancer into culture media and patient plasma. Pancreatic cancer-exosomes contained adrenomedullin and CA19-9, readily entered β cells through caveolin-mediated endocytosis or macropinocytosis, and inhibited insulin secretion. Adrenomedullin in pancreatic cancer exosomes interacted with its receptor on β cells. Adrenomedullin receptor blockade abrogated the inhibitory effect of exosomes on insulin secretion. β cells exposed to adrenomedullin or pancreatic cancer exosomes showed upregulation of ER stress genes and increased reactive oxygen/nitrogen species. Pancreatic cancer causes paraneoplastic β-cell dysfunction by shedding adrenomedullin(+)/CA19-9(+) exosomes into

  7. Impact of fetal and neonatal environment on beta cell function and development of diabetes

    DEFF Research Database (Denmark)

    Nielsen, Jens H; Haase, Tobias N; Jaksch, Caroline

    2014-01-01

    on the beta cells in both the mother and the fetus and how various conditions like diabetes, obesity, overnutrition and undernutrition during and after pregnancy may influence the ability of the offspring to adapt to changes in insulin demand later in life. The influence of environmental factors including...... that the intrauterine environment during pregnancy has an impact on the gene expression that may persist until adulthood and cause metabolic diseases like obesity and type 2 diabetes. As the pancreatic beta cells are crucial in the regulation of metabolism this article will describe the influence of normal pregnancy...... nutrients and gut microbiota on appetite regulation, mitochondrial activity and the immune system that may affect beta cell growth and function directly and indirectly is discussed. The possible role of epigenetic changes in the transgenerational transmission of the adverse programming may be the most...

  8. Pancreatic islet regeneration: Therapeutic potential, unknowns and controversy

    Directory of Open Access Journals (Sweden)

    Ingrid L. Cockburn

    2015-07-01

    Full Text Available Glucose homeostasis in mammals is primarily maintained by the insulin-secreting β-cells contained within pancreas-resident islets of Langerhans. Gross disruption of this glucose regulation as a result of pancreatic dysfunction frequently results in diabetes, which is currently a major health concern in South Africa, as well as globally. For many years, researchers have realised that the pancreas, and specifically the islets of Langerhans, have a regenerative capacity, as islet mass has frequently been shown to increase following induced pancreatic injury. Given that gross β-cell loss contributes significantly to the pathogenesis of both type 1 and type 2 diabetes, endogenous pancreatic islet regeneration has been investigated extensively as a potential β-cell replacement therapy for diabetes. From the extensive research conducted on pancreatic regeneration, opposing findings and opinions have arisen as to how, and more recently even if, pancreatic regeneration occurs following induced injury. In this review, we outline and discuss the three primary mechanisms by which pancreatic regeneration is proposed to occur: neogenesis, β-cell replication and transdifferentiation. We further explain some of the advanced techniques used in pancreatic regeneration research, and conclude that despite the technologically advanced research tools available to researchers today, the mechanisms governing pancreatic regeneration may remain elusive until more powerful techniques are developed to allow for real-time, live-cell assessment of morphology and gene expression within the pancreas.

  9. Curcumin Modulates Pancreatic Adenocarcinoma Cell-Derived Exosomal Function

    Science.gov (United States)

    Osterman, Carlos J. Diaz; Lynch, James C.; Leaf, Patrick; Gonda, Amber; Ferguson Bennit, Heather R.; Griffiths, Duncan; Wall, Nathan R.

    2015-01-01

    Pancreatic cancer has the highest mortality rates of all cancer types. One potential explanation for the aggressiveness of this disease is that cancer cells have been found to communicate with one another using membrane-bound vesicles known as exosomes. These exosomes carry pro-survival molecules and increase the proliferation, survival, and metastatic potential of recipient cells, suggesting that tumor-derived exosomes are powerful drivers of tumor progression. Thus, to successfully address and eradicate pancreatic cancer, it is imperative to develop therapeutic strategies that neutralize cancer cells and exosomes simultaneously. Curcumin, a turmeric root derivative, has been shown to have potent anti-cancer and anti-inflammatory effects in vitro and in vivo. Recent studies have suggested that exosomal curcumin exerts anti-inflammatory properties on recipient cells. However, curcumin’s effects on exosomal pro-tumor function have yet to be determined. We hypothesize that curcumin will alter the pro-survival role of exosomes from pancreatic cancer cells toward a pro-death role, resulting in reduced cell viability of recipient pancreatic cancer cells. The main objective of this study was to determine the functional alterations of exosomes released by pancreatic cancer cells exposed to curcumin compared to exosomes from untreated pancreatic cancer cells. We demonstrate, using an in vitro cell culture model involving pancreatic adenocarcinoma cell lines PANC-1 and MIA PaCa-2, that curcumin is incorporated into exosomes isolated from curcumin-treated pancreatic cancer cells as observed by spectral studies and fluorescence microscopy. Furthermore, curcumin is delivered to recipient pancreatic cancer cells via exosomes, promoting cytotoxicity as demonstrated by Hoffman modulation contrast microscopy as well as AlamarBlue and Trypan blue exclusion assays. Collectively, these data suggest that the efficacy of curcumin may be enhanced in pancreatic cancer cells through

  10. Urtica Dioica Distillate Regenerates Pancreatic Beta Cells in Streptozotocin-Induced Diabetic Rats

    Science.gov (United States)

    Gohari, Ali; Noorafshan, Ali; Akmali, Masoumeh; Zamani-Garmsiri, Fahimeh; Seghatoleslam, Atefeh

    2018-01-01

    Background Urtica dioica is known as an anti-hyperglycemic plant. Urtica dioica distillate (UD) is a traditional Iranian drink, locally known as “aragh gazaneh”. In spite of its widespread consumption in Iran, according to traditional Iranian medicine, there is no scientific report on the usefulness of UD for diabetic patients. This survey was designed to evaluate its protective effects for the recovery from diabetes by determining the serum insulin, blood glucose, volume of pancreatic islets, and the number and volume of β-cells in diabetic rats. Methods A total of 48 Sprague-Dawley male rats (200-250 g) were randomly distributed into 6 groups (n=8), including non-diabetic plus distilled water (DW), non-diabetic plus UD, diabetic plus DW, diabetic plus UD, diabetic plus insulin, and diabetic plus glibenclamide. DW, UD, and glibenclamide were administered via intragastric gavage and insulin was injected subcutaneously. After four weeks of experiments, blood samples were collected for serum insulin and blood glucose assay. Pancreas was also evaluated using stereological method. The SPSS software was used for statistical analysis. Kruskal-Wallis, repeated measurements, and Mann-Whitney U test were applied for comparisons between the groups. Results The treatment of diabetic rats with UD reduced the blood glucose dramatically (P<0.001) and increased serum insulin levels significantly (P=0.03) in comparison to the diabetic plus DW rats. Treatment with UD did not affect the mean β-cell volumes in the diabetic rats when compared to the diabetic plus DW rats, but the islet volumes and β-cell numbers were significantly recovered. Conclusion UD treatment in diabetic rats improves hyperglycemia by partially restoring plasma insulin levels. The data suggest that UD prevents islet atrophy and/or regenerate pancreatic β-cells. PMID:29749986

  11. Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

    Energy Technology Data Exchange (ETDEWEB)

    Lubaczeuski, C.; Balbo, S.L. [Laboratório de Fisiologia Endócrina e Metabolismo, Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Cascavel, PR (Brazil); Ribeiro, R.A. [Universidade Federal do Rio de Janeiro, Macaé, RJ (Brazil); Vettorazzi, J.F.; Santos-Silva, J.C.; Carneiro, E.M. [Laboratório de Pâncreas Endócrino e Metabolismo, Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP (Brazil); Bonfleur, M.L. [Laboratório de Fisiologia Endócrina e Metabolismo, Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Cascavel, PR (Brazil)

    2015-02-24

    The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca{sup 2+} mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca{sup 2+} mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats.

  12. RAS/ERK modulates TGFbeta-regulated PTEN expression in human pancreatic adenocarcinoma cells.

    Science.gov (United States)

    Chow, Jimmy Y C; Quach, Khai T; Cabrera, Betty L; Cabral, Jennifer A; Beck, Stayce E; Carethers, John M

    2007-11-01

    Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is rarely mutated in pancreatic cancers, but its regulation by transforming growth factor (TGF)-beta might mediate growth suppression and other oncogenic actions. Here, we examined the role of TGFbeta and the effects of oncogenic K-RAS/ERK upon PTEN expression in the absence of SMAD4. We utilized two SMAD4-null pancreatic cell lines, CAPAN-1 (K-RAS mutant) and BxPc-3 (WT-K-RAS), both of which express TGFbeta surface receptors. Cells were treated with TGFbeta1 and separated into cytosolic/nuclear fractions for western blotting with phospho-SMAD2, SMAD 2, 4 phospho-ATP-dependent tyrosine kinases (Akt), Akt and PTEN antibodies. PTEN mRNA levels were assessed by reverse transcriptase-polymerase chain reaction. The MEK1 inhibitor, PD98059, was used to block the downstream action of oncogenic K-RAS/ERK, as was a dominant-negative (DN) K-RAS construct. TGFbeta increased phospho-SMAD2 in both cytosolic and nuclear fractions. PD98059 treatment further increased phospho-SMAD2 in the nucleus of both pancreatic cell lines, and DN-K-RAS further improved SMAD translocation in K-RAS mutant CAPAN cells. TGFbeta treatment significantly suppressed PTEN protein levels concomitant with activation of Akt by 48 h through transcriptional reduction of PTEN mRNA that was evident by 6 h. TGFbeta-induced PTEN suppression was reversed by PD98059 and DN-K-RAS compared with treatments without TGFbeta. TGFbeta-induced PTEN expression was inversely related to cellular proliferation. Thus, oncogenic K-RAS/ERK in pancreatic adenocarcinoma facilitates TGFbeta-induced transcriptional down-regulation of the tumor suppressor PTEN in a SMAD4-independent manner and could constitute a signaling switch mechanism from growth suppression to growth promotion in pancreatic cancers.

  13. Pancreatic HIF2α Stabilization Leads to Chronic Pancreatitis and Predisposes to Mucinous Cystic Neoplasm

    Directory of Open Access Journals (Sweden)

    Heather K. Schofield

    2018-01-01

    Conclusions: We show that pancreatic HIF2α stabilization disrupts pancreatic homeostasis, leading to chronic pancreatitis, and, in the context of oncogenic Kras, MCN formation. These findings provide new mouse models of both chronic pancreatitis and MCN, as well as illustrate the importance of hypoxia signaling in the pancreas.

  14. Influence of High Aspect Ratio Vessel Cell Culture on TNF-Alpha, Insulin Secretion and Glucose Homeostasis in Pancreatic Islets of Langerhans from Wistar Furth Rats

    Science.gov (United States)

    Tobin, Brian W.a; Leeper-Woodford, Sandra K.

    1999-01-01

    The present studies were carried out to determine the influence of a ground based microgravity paradigm, utilizing the High Aspect Ratio Vessel (HARV) cell culture upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF-alpha) production of pancreatic islets of Langerhans. An additional aim was to elucidate alterations in insulin secretion and glucose utilization using the HARV low shear, gravity averaged vector, cell culture technique. Islets were isolated (1726 +/- 117, 150 micron islet equivalent units) from Wistar Furth rats and assigned to four treatment groups: 1) HARV, 2) HARV plus LPS, 3) static culture, 4) static culture plus LPS. Following 48 hours of culture, insulin concentration was increased in both HARV and static cultures (palpha (L929 cytotoxicity assay) and was measured at selected time points for 48 hours. TNF-alpha was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (palpha is associated with a decreased insulin secretion is intriguing, both as it relates to in-flight investigations, and as it may provide insight into the pathophysiology of Type I and Type 11 diabetes. Glucose concentration in islet medium was lesser throughout the experiment in static cultures, suggesting a decreased reliance upon glucose as a metabolic substrate in the islets cultured in HARVS. In conclusion, the present studies demonstrate alterations in LPS induced TNF-alpha production of pancreatic islets of Langerhans, favoring a lesser TNF production in the microgravity HARV paradigm. Additionally, alterations in fuel homeostasis may be promulgated by HARV culture. The clinical and physiological significance of these observations remains to be determined.

  15. Dimethyl amiloride improves glucose homeostasis in mouse models of type 2 diabetes.

    Science.gov (United States)

    Gunawardana, Subhadra C; Head, W Steven; Piston, David W

    2008-06-01

    Dimethyl amiloride (DMA) enhances insulin secretion in the pancreatic beta-cell. DMA also enhances time-dependent potentiation (TDP) and enables TDP to occur in situations where it is normally absent. As we have demonstrated before, these effects are mediated in part through inhibition of neuronal nitric oxide synthase (nNOS), resulting in increased availability of arginine. Thus both DMA and arginine have the potential to correct the secretory defect in diabetes by enabling or enhancing TDP. In the current study we have demonstrated the ability of these agents to improve blood glucose homeostasis in three mouse models of type 2 diabetes. The pattern of TDP under different conditions indicates that inhibition of NOS is not the only mechanism through which DMA exerts its positive effects. Thus we also have explored another possible mechanism through which DMA enables/enhances TDP, via the activation of mitochondrial alpha-ketoglutarate dehydrogenase.

  16. Distinct Internalization Pathways of Human Amylin Monomers and Its Cytotoxic Oligomers in Pancreatic Cells

    Science.gov (United States)

    Trikha, Saurabh; Jeremic, Aleksandar M.

    2013-01-01

    Toxic human amylin oligomers and aggregates are implicated in the pathogenesis of type 2 diabetes mellitus (TTDM). Although recent studies have shown that pancreatic cells can recycle amylin monomers and toxic oligomers, the exact uptake mechanism and trafficking routes of these molecular forms and their significance for amylin toxicity are yet to be determined. Using pancreatic rat insulinoma (RIN-m5F) beta (β)-cells and human islets as model systems we show that monomers and oligomers cross the plasma membrane (PM) through both endocytotic and non-endocytotic (translocation) mechanisms, the predominance of which is dependent on amylin concentrations and incubation times. At low (≤100 nM) concentrations, internalization of amylin monomers in pancreatic cells is completely blocked by the selective amylin-receptor (AM-R) antagonist, AC-187, indicating an AM-R dependent mechanism. In contrast at cytotoxic (µM) concentrations monomers initially (1 hour) enter pancreatic cells by two distinct mechanisms: translocation and macropinocytosis. However, during the late stage (24 hours) monomers internalize by a clathrin-dependent but AM-R and macropinocytotic independent pathway. Like monomers a small fraction of the oligomers initially enter cells by a non-endocytotic mechanism. In contrast a majority of the oligomers at both early (1 hour) and late times (24 hours) traffic with a fluid-phase marker, dextran, to the same endocytotic compartments, the uptake of which is blocked by potent macropinocytotic inhibitors. This led to a significant increase in extra-cellular PM accumulation, in turn potentiating amylin toxicity in pancreatic cells. Our studies suggest that macropinocytosis is a major but not the only clearance mechanism for both amylin’s molecular forms, thereby serving a cyto-protective role in these cells. PMID:24019897

  17. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells.

    Science.gov (United States)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Elevated androgen levels induce hyperinsulinemia through increase in Ins1 transcription in pancreatic beta cells in female rats.

    Science.gov (United States)

    Mishra, Jay S; More, Amar S; Kumar, Sathish

    2018-01-22

    Hyperandrogenism is associated with hyperinsulinemia and insulin resistance in adult females. We tested whether androgens dysregulate pancreatic beta cell function to induce hyperinsulinemia through transcriptional regulation of insulin gene (Ins) in the islets. Adult female Wistar rats implanted with dihydrotestosterone (DHT; 7.5-mg, 90-d release) or placebo pellets were examined after 10 weeks. DHT exposure increased plasma DHT levels by 2-fold similar to that in polycystic ovary syndrome in women. DHT exposure induced hyperinsulinemia with increased HOMA-IR index in fasting state and glucose intolerance and exaggerated insulin responses following glucose tolerance test. DHT females had no change in islet number, size and beta cell proliferation/apoptosis but exhibited significant mitochondrial dysfunction (higher ADP/ATP ratio, decreased mtDNA copy number, increased reactive oxygen production and downregulation of mitochondrial biogenesis) and enhanced glucose-stimulated insulin secretion. Ins expression was increased in DHT islets. In vitro incubation of control islets with DHT dose-dependently stimulated Ins transcription. Analysis of Ins1 gene revealed a putative androgen responsive element in the promoter. Chromatin-immunoprecipitation assays showed that androgen receptors bind to this element in response to DHT stimulation. Furthermore, reporter assays showed that the promoter element is highly responsive to androgens. Insulin stimulated glucose uptake in skeletal muscle was decreased with associated decrease in IRβ expression in DHT females. Our studies identified a novel androgen-mediated mechanism for the control of Ins expression via transcriptional regulation providing a molecular mechanism linking elevated androgens and hyperinsulemia. Decreased IRβ expression in the skeletal muscles may contribute, in part, to glucose intolerance in this model. © The Author(s) 2018. Published by Oxford University Press on behalf of Society for the Study of

  19. Enterovirus strain and type-specific differences in growth kinetics and virus-induced cell destruction in human pancreatic duct epithelial HPDE cells.

    Science.gov (United States)

    Smura, Teemu; Natri, Olli; Ylipaasto, Petri; Hellman, Marika; Al-Hello, Haider; Piemonti, Lorenzo; Roivainen, Merja

    2015-12-02

    Enterovirus infections have been suspected to be involved in the development of type 1 diabetes. However, the pathogenetic mechanism of enterovirus-induced type 1 diabetes is not known. Pancreatic ductal cells are closely associated with pancreatic islets. Therefore, enterovirus infections in ductal cells may also affect beta-cells and be involved in the induction of type 1 diabetes. The aim of this study was to assess the ability of different enterovirus strains to infect, replicate and produce cytopathic effect in human pancreatic ductal cells. Furthermore, the viral factors that affect these capabilities were studied. The pancreatic ductal cells were highly susceptible to enterovirus infections. Both viral growth and cytolysis were detected for several enterovirus serotypes. However, the viral growth and capability to induce cytopathic effect (cpe) did not correlate completely. Some of the virus strains replicated in ductal cells without apparent cpe. Furthermore, there were strain-specific differences in the growth kinetics and the ability to cause cpe within some serotypes. Viral adaptation experiments were carried out to study the potential genetic determinants behind these phenotypic differences. The blind-passage of non-lytic CV-B6-Schmitt strain in HPDE-cells resulted in lytic phenotype and increased progeny production. This was associated with the substitution of a single amino acid (K257E) in the virus capsid protein VP1 and the viral ability to use decay accelerating factor (DAF) as a receptor. This study demonstrates considerable plasticity in the cell tropism, receptor usage and cytolytic properties of enteroviruses and underlines the strong effect of single or few amino acid substitutions in cell tropism and lytic capabilities of a given enterovirus. Since ductal cells are anatomically close to pancreatic islets, the capability of enteroviruses to infect and destroy pancreatic ductal cells may also implicate in respect to enterovirus induced type 1

  20. Sustained beta-cell dysfunction but normalized islet mass in aged thrombospondin-1 deficient mice.

    Directory of Open Access Journals (Sweden)

    Carl Johan Drott

    Full Text Available Pancreatic islet endothelial cells have in recent years been shown to support beta-cell mass and function by paracrine interactions. Recently, we identified an islets endothelial-specific glycoprotein, thrombospondin-1 (TSP-1, that showed to be of importance for islet angiogenesis and beta-cell function in young mice. The present study aimed to investigate long-term consequences for islet morphology and beta-cell function of TSP-1 deficiency. Islet and beta-cell mass were observed increased at 10-12 weeks of age in TSP-1 deficient mice, but were normalized before 16 weeks of age when compared to wild-type controls. Islet vascularity was normal in 10-12 and 16-week-old TSP-1 deficient animals, whereas islets of one-year-old animals lacking TSP-1 were hypervascular. Beta-cell dysfunction in TSP-1 deficient animals was present at similar magnitudes between 10-12 and 52 weeks of age, as evaluated by glucose tolerance tests. The insulin secretion capacity in vivo of islets in one-year-old TSP-1 deficient animals was only ∼15% of that in wild-type animals. Using a transplantation model, we reconstituted TSP-1 in adult TSP-deficient islets. In contrast to neonatal TSP-1 deficient islets that we previously reported to regain function after TSP-1 reconstitution, adult islets failed to recover. We conclude that TSP-1 deficiency in islets causes changing vascular and endocrine morphological alterations postnatally, but is coupled to a chronic beta-cell dysfunction. The beta-cell dysfunction induced by TSP-1 deficiency is irreversible if not substituted early in life.

  1. Primary cilia and coordination of signaling pathways in heart development and tissue Homeostasis

    DEFF Research Database (Denmark)

    Clement, Christian Alexandro

    of primary cilia in coordinating Hh signaling in human pancreatic development and postnatal tissue homeostasis. In cultures of human pancreatic duct adenocarcinoma cell lines PANC-1 and CFPAC-1, Ptc in addition to Gli2 and Smo localize to primary cilia. These findings are consistent with the idea...... that the primary cilium continues to coordinate Hh signaling in cells derived from the mature pancreas. The fact that the Hh signaling pathway is active in the CFPAC-1 and PANC-1 cell lines without Hh stimulation suggests that ciliary Hh signaling plays a potential role in tumorigenesis. In conclusion, this thesis...

  2. Relationship of visfatin level to pancreatic endocrine hormone level, HOMA-IR index, and HOMA β-cell index in overweight women who performed hydraulic resistance exercise

    OpenAIRE

    Ha, Chang Ho; Swearingin, Brenda; Jeon, Yong Kyun

    2015-01-01

    [Purpose] This study aimed to examine the correlation of visfatin level to pancreatic endocrine hormone level, homeostasis model assessment of insulin resistance (HOMA-IR) index, and HOMA β-cell index in hydraulic resistance exercise. Furthermore, it investigated the relationship between visfatin level and other variables affected by exercise in overweight women. [Subjects and Methods] The exercise group trained for 12 weeks, 70 minutes/day, 5 days/week. Visfatin level, pancreatic endocrine h...

  3. In vivo and in vitro characterization of [18F]-FE-(+)-DTBZ as a tracer for beta-cell mass

    International Nuclear Information System (INIS)

    Eriksson, Olof; Jahan, Mahabuba; Johnstroem, Peter; Korsgren, Olle; Sundin, Anders; Halldin, Christer; Johansson, Lars

    2010-01-01

    Introduction: The positron emission tomography (PET) tracer 9-[ 18 F]fluoroethyl-(+)-dihydrotetrabenazine ([ 18 F]-FE-(+)-DTBZ) is a potential candidate for quantifying beta-cell mass in vivo. The purpose was to investigate in vitro and in vivo utility of this tracer for the assessment of beta-cell mass. Methods: Three pigs were intravenously administered [ 18 F]-FE-(+)-DTBZ and examined by PET/computed tomography. Binding parameters were estimated by kinetic modeling. In vitro k D and B max were determined by saturation binding studies of endocrine and exocrine human tissue homogenates. In vitro pancreatic uptake was determined by tissue autoradiography with pancreases from patients with types 1 (T1DM) and 2 diabetes mellitus (T2DM) and healthy controls. Results: [ 18 F]-FE-(+)-DTBZ had a k D of 3.5±1.0 nM, a B max of 382±108 fmol/mg protein and a specificity of 89±1.8% in islet homogenates. The total exocrine uptake was lower and 65% was nondisplaceable. No uptake difference was observed in pancreatic tissue slices from patients with T1DM, T2DM or healthy controls. The in vivo porcine pancreatic uptake reached a peak of standardized uptake value (SUV) of 2.8 with a low distribution volume ratio in all animals. Moderate to high tracer uptake was identified in the bile system and in bone. Conclusions: [ 18 F]-FE-(+)-DTBZ binds to vesicular monoamine transporter 2 (VMAT2) with high specificity in pure islet tissue in vitro. However, there is high nondisplaceable binding to exocrine tissue. In addition, in vivo tracer metabolism and dehalogenation result in severe underestimation of porcine pancreatic VMAT2 expression and BCM. The results do not support [ 18 F]-FE-(+)-DTBZ as a suitable tracer for in vivo beta-cell imaging.

  4. Chemical strategies for pancreatic β cell differentiation, reprogramming, and regeneration.

    Science.gov (United States)

    Ma, Xiaojie; Zhu, Saiyong

    2017-04-01

    Generation of unlimited functional pancreatic β cells is critical for the study of pancreatic biology and treatment of diabetes mellitus. Recent advances have suggested several promising directions, including directed differentiation of pancreatic β cells from pluripotent stem cells, reprogramming of pancreatic β cells from other types of somatic cells, and stimulated proliferation and enhanced functions of existing pancreatic β cells. Small molecules are useful in generating unlimited numbers of functional pancreatic cells in vitro and could be further developed as drugs to stimulate endogenous pancreatic regeneration. Here, we provide an updated summary of recent major achievements in pancreatic β cell differentiation, reprogramming, proliferation, and function. These studies will eventually lead to significant advances in the field of pancreatic biology and regeneration. © The Author 2017. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Cancer Stem Cells in Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Qi; Zhao, Yue; Renner, Andrea; Niess, Hanno; Seeliger, Hendrik; Jauch, Karl-Walter; Bruns, Christiane J., E-mail: christiane.bruns@med.uni-muenchen.de [Department of Surgery, Ludwig Maximilian University of Munich, Klinikum Grosshadern, Marchioninistr. 15, D-81377, Munich (Germany)

    2010-08-19

    Pancreatic cancer is an aggressive malignant solid tumor well-known by early metastasis, local invasion, resistance to standard chemo- and radiotherapy and poor prognosis. Increasing evidence indicates that pancreatic cancer is initiated and propagated by cancer stem cells (CSCs). Here we review the current research results regarding CSCs in pancreatic cancer and discuss the different markers identifying pancreatic CSCs. This review will focus on metastasis, microRNA regulation and anti-CSC therapy in pancreatic cancer.

  6. Osmotic homeostasis and NKLy lymphoma cells radiosensitivity

    International Nuclear Information System (INIS)

    Tishchenko, V.V.; Magda, I.N.

    1992-01-01

    In experiments with cells of ascites NKLy lymphoma differing in ploidy and position in the cell cycle, a study was made of the radiosensitivity, osmotic homeostasis peculiarities and thermoradiation changes in potassium content. It was shown that the resistance of osmotic homeostasis of NKLy cells to thermoradiation correlated with their radioresistance

  7. Clostridium butyricum CGMCC0313.1 Protects against Autoimmune Diabetes by Modulating Intestinal Immune Homeostasis and Inducing Pancreatic Regulatory T Cells

    Directory of Open Access Journals (Sweden)

    Lingling Jia

    2017-10-01

    Full Text Available Recent evidence indicates that indigenous Clostridium species induce colonic regulatory T cells (Tregs, and gut lymphocytes are able to migrate to pancreatic islets in an inflammatory environment. Thus, we speculate that supplementation with the well-characterized probiotics Clostridium butyricum CGMCC0313.1 (CB0313.1 may induce pancreatic Tregs and consequently inhibit the diabetes incidence in non-obese diabetic (NOD mice. CB0313.1 was administered daily to female NOD mice from 3 to 45 weeks of age. The control group received an equal volume of sterile water. Fasting glucose was measured twice a week. Pyrosequencing of the gut microbiota and flow cytometry of mesenteric lymph node (MLN, pancreatic lymph node (PLN, pancreatic and splenic immune cells were performed to investigate the effect of CB0313.1 treatment. Early oral administration of CB0313.1 mitigated insulitis, delayed the onset of diabetes, and improved energy metabolic dysfunction. Protection may involve increased Tregs, rebalanced Th1/Th2/Th17 cells and changes to a less proinflammatory immunological milieu in the gut, PLN, and pancreas. An increase of α4β7+ (the gut homing receptor Tregs in the PLN suggests that the mechanism may involve increased migration of gut-primed Tregs to the pancreas. Furthermore, 16S rRNA gene sequencing revealed that CB0313.1 enhanced the Firmicutes/Bacteroidetes ratio, enriched Clostridium-subgroups and butyrate-producing bacteria subgroups. Our results provide the basis for future clinical investigations in preventing type 1 diabetes by oral CB0313.1 administration.

  8. Ubiquitin fold modifier 1 (UFM1 and its target UFBP1 protect pancreatic beta cells from ER stress-induced apoptosis.

    Directory of Open Access Journals (Sweden)

    Katleen Lemaire

    Full Text Available UFM1 is a member of the ubiquitin like protein family. While the enzymatic cascade of UFM1 conjugation has been elucidated in recent years, the biological function remains largely unknown. In this report we demonstrate that the recently identified C20orf116, which we name UFM1-binding protein 1 containing a PCI domain (UFBP1, and CDK5RAP3 interact with UFM1. Components of the UFM1 conjugation pathway (UFM1, UFBP1, UFL1 and CDK5RAP3 are highly expressed in pancreatic islets of Langerhans and some other secretory tissues. Co-localization of UFM1 with UFBP1 in the endoplasmic reticulum (ER depends on UFBP1. We demonstrate that ER stress, which is common in secretory cells, induces expression of Ufm1, Ufbp1 and Ufl1 in the beta-cell line INS-1E. siRNA-mediated Ufm1 or Ufbp1 knockdown enhances apoptosis upon ER stress. Silencing the E3 enzyme UFL1, results in similar outcomes, suggesting that UFM1-UFBP1 conjugation is required to prevent ER stress-induced apoptosis. Together, our data suggest that UFM1-UFBP1 participate in preventing ER stress-induced apoptosis in protein secretory cells.

  9. Cancer Stem Cells in Pancreatic Cancer

    Science.gov (United States)

    Bao, Qi; Zhao, Yue; Renner, Andrea; Niess, Hanno; Seeliger, Hendrik; Jauch, Karl-Walter; Bruns, Christiane J.

    2010-01-01

    Pancreatic cancer is an aggressive malignant solid tumor well-known by early metastasis, local invasion, resistance to standard chemo- and radiotherapy and poor prognosis. Increasing evidence indicates that pancreatic cancer is initiated and propagated by cancer stem cells (CSCs). Here we review the current research results regarding CSCs in pancreatic cancer and discuss the different markers identifying pancreatic CSCs. This review will focus on metastasis, microRNA regulation and anti-CSC therapy in pancreatic cancer. PMID:24281178

  10. Cancer Stem Cells in Pancreatic Cancer

    Directory of Open Access Journals (Sweden)

    Karl-Walter Jauch

    2010-08-01

    Full Text Available Pancreatic cancer is an aggressive malignant solid tumor well-known by early metastasis, local invasion, resistance to standard chemo- and radiotherapy and poor prognosis. Increasing evidence indicates that pancreatic cancer is initiated and propagated by cancer stem cells (CSCs. Here we review the current research results regarding CSCs in pancreatic cancer and discuss the different markers identifying pancreatic CSCs. This review will focus on metastasis, microRNA regulation and anti-CSC therapy in pancreatic cancer.

  11. Engineered T cells for pancreatic cancer treatment

    Science.gov (United States)

    Katari, Usha L; Keirnan, Jacqueline M; Worth, Anna C; Hodges, Sally E; Leen, Ann M; Fisher, William E; Vera, Juan F

    2011-01-01

    Objective Conventional chemotherapy and radiotherapy produce marginal survival benefits in pancreatic cancer, underscoring the need for novel therapies. The aim of this study is to develop an adoptive T cell transfer approach to target tumours expressing prostate stem cell antigen (PSCA), a tumour-associated antigen that is frequently expressed by pancreatic cancer cells. Methods Expression of PSCA on cell lines and primary tumour samples was confirmed by immunohistochemistry. Healthy donor- and patient-derived T cells were isolated, activated in vitro using CD3/CD28, and transduced with a retroviral vector encoding a chimeric antigen receptor (CAR) targeting PSCA. The ability of these cells to kill tumour cells was analysed by chromium-51 (Cr51) release. Results Prostate stem cell antigen was expressed on >70% of the primary tumour samples screened. Activated, CAR-modified T cells could be readily generated in clinically relevant numbers and were specifically able to kill PSCA-expressing pancreatic cancer cell lines with no non-specific killing of PSCA-negative target cells, thus indicating the potential efficacy and safety of this approach. Conclusions Prostate stem cell antigen is frequently expressed on pancreatic cancer cells and can be targeted for immune-mediated destruction using CAR-modified, adoptively transferred T cells. The safety and efficacy of this approach indicate that it deserves further study and may represent a promising novel treatment for patients with pancreatic cancer. PMID:21843265

  12. CRFR1 is expressed on pancreatic beta cells, promotes beta cell proliferation, and potentiates insulin secretion in a glucose-dependent manner

    DEFF Research Database (Denmark)

    Huising, Mark O; van der Meulen, Talitha; Vaughan, Joan M

    2009-01-01

    Corticotropin-releasing factor (CRF), originally characterized as the principal neuroregulator of the hypothalamus-pituitary-adrenal axis, has broad central and peripheral distribution and actions. We demonstrate the presence of CRF receptor type 1 (CRFR1) on primary beta cells and show that acti...

  13. Enhanced Glucose Tolerance and Pancreatic Beta Cell Function by Low Dose Aspirin in Hyperglycemic Insulin-Resistant Type 2 Diabetic Goto-Kakizaki (GK Rats

    Directory of Open Access Journals (Sweden)

    Layla Amiri

    2015-07-01

    Full Text Available Background/Aim: Type 2 diabetes is the most common metabolic disorder, characterized by insulin resistance and pancreatic islet beta-cell failure. The most common complications associated with type 2 diabetes are hyperinsulinemia, hyperglycemia, hyperlipidemia, increased inflammatory and reduced insulin response. Aspirin (ASA and other non-steroidal anti-inflammatory drugs (NSAIDs have been associated with the prevention of diabetes, obesity and related cardiovascular disorders. Aspirin has been used in many clinical and experimental trials for the prevention of diabetes and associated complications. Methods: In this study, five month old Goto-Kakizaki (GK rats, which showed signs of mild hyperglycemia (fasting blood glucose 80-95 mg/dl vs 55-60 mg/dl Wistar control rats were used. Two subgroups of GK and Wistar control rats were injected intraperitoneally with 100 mg aspirin/kg body weight/ day for 5 weeks. Animals were sacrificed and blood and tissues were collected after performing glucose tolerance (2 h post 2g IP glucose ingestion tests in experimental and control groups. Results: Aspirin caused a moderate decrease in hyperglycemia. However, we observed a significant improvement in glucose tolerance after ASA treatment in GK rats compared to the nondiabetic Wistar rats. Also, the ASA treated GK rats exhibited a significant decrease in insulinemia. ASA treatment also caused a marked reduction in the pro-inflammatory prostaglandin, PGE2, which was significantly higher in GK rats. On the other hand, no significant organ toxicity was observed after ASA treatment at this dose and time period. However, the total cholesterol and lipoprotein levels were significantly increased in GK rats, which decreased after ASA treatment. Immunofluorescence staining for insulin/glucagon secreting pancreatic cells showed improved beta-cell structural and functional integrity in ASA-treated rats which was also confirmed by SDS-PAGE and Western blot analysis

  14. Phosphorylation events implicating p38 and PI3K mediate tungstate-effects in MIN6 beta cells

    International Nuclear Information System (INIS)

    Piquer, Sandra; Barcelo-Batllori, Silvia; Julia, Marta; Marzo, Nuria; Nadal, Belen; Guinovart, Joan J.; Gomis, Ramon

    2007-01-01

    Oral administration of sodium tungstate is an effective treatment for diabetes in animal models. Several lines of evidence indicate the pancreatic beta cell as one of the targets of tungstate action. Here, we examined the molecular mechanism by which this compound exerts its effects on the beta cell line MIN6. Tungstate treatment induced phosphorylation and subsequent activation of p38 and PI3K which in turn are implicated in tungstate PDX-1 nuclear localization and activation. Although no effect was observed in glucose-induced insulin secretion we found that tungstate activates basal insulin release, a process driven, at least in part, by activation of p38. These results show a direct involvement of p38 and PI3K phosphorylation in the mechanism of action of tungstate in the beta cell

  15. In vivo and in vitro characterization of [{sup 18}F]-FE-(+)-DTBZ as a tracer for beta-cell mass

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, Olof [Division of Radiology, Department of Oncology, Radiology and Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden)], E-mail: olof.eriksson@radiol.uu.se; Jahan, Mahabuba [Department of Clinical Neuroscience, Karolinska Institute, Section of Psychiatry, Karolinska Hospital, 171 76, Stockholm (Sweden); Johnstroem, Peter [Department of Clinical Neuroscience, Karolinska Institute, Section of Psychiatry, Karolinska Hospital, 171 76, Stockholm (Sweden); CNS and Pain Control, AstraZeneca R and D, 151 36, Soedertaelje (Sweden); Korsgren, Olle [Department of Oncology, Radiology and Clinical Immunology, Division of Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden); Sundin, Anders [Division of Radiology, Department of Oncology, Radiology and Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden); Department of Radiology, Karolinska University Hospital, 171 76, Stockholm (Sweden); Halldin, Christer [Department of Clinical Neuroscience, Karolinska Institute, Section of Psychiatry, Karolinska Hospital, 171 76, Stockholm (Sweden); Johansson, Lars [Division of Radiology, Department of Oncology, Radiology and Clinical Immunology, University Hospital, 751 87 Uppsala (Sweden); AstraZeneca R and D, 431 50, Moelndal (Sweden)

    2010-04-15

    Introduction: The positron emission tomography (PET) tracer 9-[{sup 18}F]fluoroethyl-(+)-dihydrotetrabenazine ([{sup 18}F]-FE-(+)-DTBZ) is a potential candidate for quantifying beta-cell mass in vivo. The purpose was to investigate in vitro and in vivo utility of this tracer for the assessment of beta-cell mass. Methods: Three pigs were intravenously administered [{sup 18}F]-FE-(+)-DTBZ and examined by PET/computed tomography. Binding parameters were estimated by kinetic modeling. In vitro k{sub D} and B{sub max} were determined by saturation binding studies of endocrine and exocrine human tissue homogenates. In vitro pancreatic uptake was determined by tissue autoradiography with pancreases from patients with types 1 (T1DM) and 2 diabetes mellitus (T2DM) and healthy controls. Results: [{sup 18}F]-FE-(+)-DTBZ had a k{sub D} of 3.5{+-}1.0 nM, a B{sub max} of 382{+-}108 fmol/mg protein and a specificity of 89{+-}1.8% in islet homogenates. The total exocrine uptake was lower and 65% was nondisplaceable. No uptake difference was observed in pancreatic tissue slices from patients with T1DM, T2DM or healthy controls. The in vivo porcine pancreatic uptake reached a peak of standardized uptake value (SUV) of 2.8 with a low distribution volume ratio in all animals. Moderate to high tracer uptake was identified in the bile system and in bone. Conclusions: [{sup 18}F]-FE-(+)-DTBZ binds to vesicular monoamine transporter 2 (VMAT2) with high specificity in pure islet tissue in vitro. However, there is high nondisplaceable binding to exocrine tissue. In addition, in vivo tracer metabolism and dehalogenation result in severe underestimation of porcine pancreatic VMAT2 expression and BCM. The results do not support [{sup 18}F]-FE-(+)-DTBZ as a suitable tracer for in vivo beta-cell imaging.

  16. Do immunotherapy and beta cell replacement play a synergistic role in the treatment of type 1 diabetes?

    Science.gov (United States)

    Li, Dong-Sheng; Warnock, Garth L; Tu, Han-Jun; Ao, Ziliang; He, Zehua; Lu, Hong; Dai, Long-Jun

    2009-10-07

    Type 1 diabetes (T1D) is the result of the autoimmune response against pancreatic insulin-producing ss-cells. Its ultimate consequence is beta-cell insufficiency-mediated dysregulation of blood glucose control. In terms of T1D treatment, immunotherapy addresses the cause of T1D, mainly through re-setting the balance between autoimmunity and regulatory mechanisms. Regulatory T cells play an important role in this immune intervention. An alternative T1D treatment is beta-cell replacement, which can reverse the consequence of the disease by replacing destroyed beta-cells in the diabetic pancreas. The applicable insulin-producing cells can be directly obtained from islet transplantation or generated from other cell sources such as autologous adult stem cells, embryonic stem cells, and induced pluripotent stem cells. In this review, we summarize the recent research progress and analyze the possible advantages and disadvantages of these two therapeutic options especially focusing on the potential synergistic effect on T1D treatment. Exploring the optimal combination of immunotherapy and beta-cell replacement will pave the way to the most effective cure for this devastating disease.

  17. Beta cell adaptation in pregnancy

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis

    2016-01-01

    Pregnancy is associated with a compensatory increase in beta cell mass. It is well established that somatolactogenic hormones contribute to the expansion both indirectly by their insulin antagonistic effects and directly by their mitogenic effects on the beta cells via receptors for prolactin...... and growth hormone expressed in rodent beta cells. However, the beta cell expansion in human pregnancy seems to occur by neogenesis of beta cells from putative progenitor cells rather than by proliferation of existing beta cells. Claes Hellerström has pioneered the research on beta cell growth for decades...... in the expansion of the beta cell mass in human pregnancy, and the relative roles of endocrine factors and nutrients....

  18. Silencing of NRF2 Reduces the Expression of ALDH1A1 and ALDH3A1 and Sensitizes to 5-FU in Pancreatic Cancer Cells

    Directory of Open Access Journals (Sweden)

    Hong-Quan Duong

    2017-07-01

    Full Text Available Pancreatic cancer remains an intractable cancer with a poor five-year survival rate, which requires new therapeutic modalities based on the biology of pancreatic oncogenesis. Nuclear factor E2 related factor-2 (NRF2, a key cytoprotective nuclear transcription factor, regulates antioxidant production, reduction, detoxification and drug efflux proteins. It also plays an essential role in cell homeostasis, cell proliferation and resistance to chemotherapy. We aimed to evaluate the possibility that modulation of NRF2 expression could be effective in the treatment of pancreatic cancer cells. We investigated whether the depletion of NRF2 by using small interfering RNAs (siRNAs is effective in the expression of biomarkers of pancreatic cancer stemness such as aldehyde dehydrogenase 1 family, member A1 (ALDH1A1 and aldehyde dehydrogenase 3 family, member A1 (ALDH3A1. NRF2 knockdown markedly reduced the expression of NRF2 and glutamate-cysteine ligase catalytic subunit (GCLC in cell lines established from pancreatic cancers. NRF2 silencing also decreased the ALDH1A1 and ALDH3A1 expression. Furthermore, this NRF2 depletion enhanced the antiproliferative effects of the chemotherapeutic agent, 5-fluorouracil (5-FU in pancreatic cancer cells.

  19. Regulation of beta cell replication

    DEFF Research Database (Denmark)

    Lee, Ying C; Nielsen, Jens Høiriis

    2008-01-01

    Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

  20. Islet Cells Serve as Cells of Origin of Pancreatic Gastrin-Positive Endocrine Tumors

    DEFF Research Database (Denmark)

    Bonnavion, Rémy; Teinturier, Romain; Jaafar, Rami

    2015-01-01

    The cells of origin of pancreatic gastrinomas remain an enigma, since no gastrin-expressing cells are found in the normal adult pancreas. It was proposed that the cellular origin of pancreatic gastrinomas may come from either the pancreatic cells themselves or gastrin-expressing cells which have ...

  1. Immune-mediated beta-cell destruction in vitro and in vivo-A pivotal role for galectin-3

    DEFF Research Database (Denmark)

    Karlsen, Allan E; Størling, Zenia M; Sparre, Thomas

    2006-01-01

    Pro-apoptotic cytokines are toxic to the pancreatic beta-cells and have been associated with the pathogenesis of Type 1 diabetes (T1D). Proteome analysis of IL-1beta exposed isolated rat islets identified galectin-3 (gal-3) as the most up-regulated protein. Here analysis of human and rat islets a....... In summary, combined proteome-transcriptome-genome and functional analyses identify gal-3 as a candidate gene/protein in T1D susceptibility that may prove valuable in future intervention/prevention strategies....

  2. Susceptibility of ATM-deficient pancreatic cancer cells to radiation.

    Science.gov (United States)

    Ayars, Michael; Eshleman, James; Goggins, Michael

    2017-05-19

    Ataxia telangiectasia mutated (ATM) is inactivated in a significant minority of pancreatic ductal adenocarcinomas and may be predictor of treatment response. We determined if ATM deficiency renders pancreatic cancer cells more sensitive to fractionated radiation or commonly used chemotherapeutics. ATM expression was knocked down in three pancreatic cancer cell lines using ATM-targeting shRNA. Isogenic cell lines were tested for sensitivity to several chemotherapeutic agents and radiation. DNA repair kinetics were analyzed in irradiated cells using the comet assay. We find that while rendering pancreatic cancer cells ATM-deficient did not significantly change their sensitivity to several chemotherapeutics, it did render them exquisitely sensitized to radiation. Pancreatic cancer ATM status may help predict response to radiotherapy.

  3. Specifying pancreatic endocrine cell fates.

    Science.gov (United States)

    Collombat, Patrick; Hecksher-Sørensen, Jacob; Serup, Palle; Mansouri, Ahmed

    2006-07-01

    Cell replacement therapy could represent an attractive alternative to insulin injections for the treatment of diabetes. However, this approach requires a thorough understanding of the molecular switches controlling the specification of the different pancreatic cell-types in vivo. These are derived from an apparently identical pool of cells originating from the early gut endoderm, which are successively specified towards the pancreatic, endocrine, and hormone-expressing cell lineages. Numerous studies have outlined the crucial roles exerted by transcription factors in promoting the cell destiny, defining the cell identity and maintaining a particular cell fate. This review focuses on the mechanisms regulating the morphogenesis of the pancreas with particular emphasis on recent findings concerning the transcription factor hierarchy orchestrating endocrine cell fate allocation.

  4. Bone mineral metabolism, bone mineral density, and body composition in patients with chronic pancreatitis and pancreatic exocrine insufficiency

    DEFF Research Database (Denmark)

    Haaber, Anne Birgitte; Rosenfalck, A M; Hansen, B

    2000-01-01

    Calcium and vitamin D homeostasis seem to be abnormal in patients with exocrine pancreatic dysfunction resulting from cystic fibrosis. Only a few studies have evaluated and described bone mineral metabolism in patients with chronic pancreatitis and pancreatic insufficiency....

  5. α-Ketoglutarate Promotes Pancreatic Progenitor-Like Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Jing Song

    2018-03-01

    Full Text Available A major source of β cell generation is pancreatic progenitor-like cell differentiation. Multiple studies have confirmed that stem cell metabolism plays important roles in self-renewal and proliferation. In the absence of glucose, glutamine provides the energy for cell division and growth. Furthermore, α-ketoglutarate (αKG, a precursor for glutamine synthesis, is sufficient for enabling glutamine-independent cell proliferation. We have demonstrated that αKG contributes to the large-scale proliferation of pancreatic progenitor-like cells that can provide an ample amount of clinically relevant β cells. We compared the mRNA expression of a subset of genes, the abundance of ATP, reactive oxide species, mitochondrial number, and the colony-forming frequency between mouse pancreatic CD133+ and CD133− cells. We employed Real-Time PCR, immunostaining and passage assays to investigate self-renewal and proliferation of pancreatic progenitor-like cells in a 3D culture system in the presence and absence of αKG. The energy metabolism of CD133+ cells was more prone to oxidative phosphorylation. However, in the 3D culture system, when αKG was supplemented to the culture medium, the proliferation of the pancreatic progenitor-like cells was significantly elevated. We confirmed that the presence of αKG correlated with the up-regulation of Ten-Eleven Translocation (Tet. αKG can promote the proliferation of pancreatic progenitor-like cells via the up-regulation of Tet.

  6. α-Ketoglutarate Promotes Pancreatic Progenitor-Like Cell Proliferation.

    Science.gov (United States)

    Song, Jing; Ma, Dongshen; Xing, Yun; Tang, Shanshan; Alahdal, Murad; Guo, Jiamin; Pan, Yi; Zhang, Yanfeng; Shen, Yumeng; Wu, Qiong; Lu, Zhou; Jin, Liang

    2018-03-22

    A major source of β cell generation is pancreatic progenitor-like cell differentiation. Multiple studies have confirmed that stem cell metabolism plays important roles in self-renewal and proliferation. In the absence of glucose, glutamine provides the energy for cell division and growth. Furthermore, α-ketoglutarate (αKG), a precursor for glutamine synthesis, is sufficient for enabling glutamine-independent cell proliferation. We have demonstrated that αKG contributes to the large-scale proliferation of pancreatic progenitor-like cells that can provide an ample amount of clinically relevant β cells. We compared the mRNA expression of a subset of genes, the abundance of ATP, reactive oxide species, mitochondrial number, and the colony-forming frequency between mouse pancreatic CD133⁺ and CD133 - cells. We employed Real-Time PCR, immunostaining and passage assays to investigate self-renewal and proliferation of pancreatic progenitor-like cells in a 3D culture system in the presence and absence of αKG. The energy metabolism of CD133⁺ cells was more prone to oxidative phosphorylation. However, in the 3D culture system, when αKG was supplemented to the culture medium, the proliferation of the pancreatic progenitor-like cells was significantly elevated. We confirmed that the presence of αKG correlated with the up-regulation of Ten-Eleven Translocation (Tet). αKG can promote the proliferation of pancreatic progenitor-like cells via the up-regulation of Tet.

  7. The functional performance of microencapsulated human pancreatic islet-derived precursor cells.

    Science.gov (United States)

    Montanucci, Pia; Pennoni, Ilaria; Pescara, Teresa; Blasi, Paolo; Bistoni, Giovanni; Basta, Giuseppe; Calafiore, Riccardo

    2011-12-01

    We have examined long-term cultured, human islet-derived stem/precursor cells (hIPC). Whole human islets (HI) were obtained by multi-enzymatic digestion of cadaveric donor pancreases, plated on tissue flasks, and allowed to adhere and expand for several in vitro passages, in order to obtain hIPC. We detected specific stem cell markers (Oct-4, Sox-2, Nanog, ABCG2, Klf-4, CD117) in both intact HI and hIPC. Moreover, hIPC while retaining the expression of Glut-2, Pdx-1, CK-19, and ICA-512, started re-expressing Ngn3, thereby indicating acquisition of a specific pancreatic islet beta cell-oriented phenotype identity. The intrinsic plasticity of hIPC was documented by their ability to differentiate into various germ layer-derived cell phenotypes (ie, osteocytic, adipocytic and neural), including endocrine cells associated with insulin secretory capacity. To render hIPC suitable for transplantation we have enveloped them within our highly purified, alginate-based microcapsules. Upon intraperitoneal graft in NOD/SCID mice we have observed that the microcapsules acted as three-dimensional niches favouring post-transplant hIPC differentiation and acquisition of beta cell-like functional competence. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Positive association of free triiodothyronine with pancreatic β-cell function in people with prediabetes.

    Science.gov (United States)

    Oda, T; Taneichi, H; Takahashi, K; Togashi, H; Hangai, M; Nakagawa, R; Ono, M; Matsui, M; Sasai, T; Nagasawa, K; Honma, H; Kajiwara, T; Takahashi, Y; Takebe, N; Ishigaki, Y; Satoh, J

    2015-02-01

    To analyse the effects of thyroid hormones on β-cell function and glucose metabolism in people with prediabetes who are euthyroid. A total of 111 people who were euthyroid underwent 75-g oral glucose tolerance tests, of whom 52 were assigned to the normal glucose tolerance and 59 to the prediabetes groups. Homeostatic model assessment of β-cell function, insulinogenic index and areas under the curve for insulin and glucose were evaluated as indices of pancreatic β-cell function. In both groups, BMI, fasting insulin, homeostasis model assessment ratio and HDL cholesterol correlated significantly with all indices of pancreatic β-cell function. Free triiodothyronine correlated positively with all insulin secretion indices in the prediabetes group. Multiple linear regression analysis showed that free triiodothyronine was an independent variable that had a positive correlation with all indices of β-cell function in the prediabetes group. By contrast, no such correlation was found in the normal glucose tolerance group. Free triiodothyronine is associated with both basal and glucose-stimulated insulin secretion in people with prediabetes who are euthyroid; therefore, the regulation of insulin secretion by thyroid hormones is a potentially novel therapeutic target for the treatment of diabetes. © 2014 The Authors. Diabetic Medicine © 2014 Diabetes UK.

  9. Divergent Effects of Dendritic Cells on Pancreatitis

    Science.gov (United States)

    2015-09-01

    role of dendritic cells in pancreatitis. Dendritic cells are professional antigen presenting cells which initiate innate and adaptive immune... Lymphoid -tissue-specific homing of bone- marrow-derived dendritic cells . Blood. 113:6638–6647. http://dx.doi .org/10.1182/blood-2009-02-204321 Dapito...Award Number: W81XWH-12-1-0313 TITLE: Divergent Effects of Dendritic Cells on Pancreatitis PRINCIPAL INVESTIGATOR: Dr. George Miller

  10. Beta-endorphin Cell Therapy for Cancer Prevention

    OpenAIRE

    Zhang, Changqing; Murugan, Sengottuvelan; Boyadjieva, Nadka; Jabbar, Shaima; Shrivastava, Pallavi; Sarkar, Dipak K.

    2014-01-01

    Beta-endorphin (BEP) producing neuron in the hypothalamus plays a key role in brining the stress axis to a state of homeostasis and maintaining body immune defense system. Long-term delivery of BEP to obtain beneficial effect on chemoprevention is challenging, since the peptide rapidly develop tolerance. Using rats as animal model, we show here that transplantation of beta-endorphin neurons into the hypothalamus suppressed carcinogens- and hormone-induced cancers in various tissues and preven...

  11. Mesenchymal Stromal Cell Therapy for Pancreatitis: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Sara M. Ahmed

    2018-01-01

    Full Text Available Background. Based on animal studies, adult mesenchymal stromal cells (MSCs are promising for the treatment of pancreatitis. However, the best type of this form of cell therapy and its mechanism of action remain unclear. Methods. We searched the PubMed, Web of Science, Scopus, Google Scholar, and Clinical Trials.gov websites for studies using MSCs as a therapy for both acute and chronic pancreatitis published until September 2017. Results. We identified 276 publications; of these publications, 18 met our inclusion criteria. In animal studies, stem cell therapy was applied more frequently for acute pancreatitis than for chronic pancreatitis. No clinical trials were identified. MSC therapy ameliorated pancreatic inflammation in acute pancreatitis and pancreatic fibrosis in chronic pancreatitis. Bone marrow and umbilical cord MSCs were the most frequently administered cell types. Due to the substantial heterogeneity among the studies regarding the type, source, and dose of MSCs used, conducting a meta-analysis was not feasible to determine the best type of MSCs. Conclusion. The available data were insufficient for determining the best type of MSCs for the treatment of acute or chronic pancreatitis; therefore, clinical trials investigating the use of MSCs as therapy for pancreatitis are not warranted.

  12. Characterization of Phospholipids in Insulin Secretory Granules and Mitochondria in Pancreatic Beta Cells and Their Changes with Glucose Stimulation*

    Science.gov (United States)

    MacDonald, Michael J.; Ade, Lacmbouh; Ntambi, James M.; Ansari, Israr-Ul H.; Stoker, Scott W.

    2015-01-01

    The lipid composition of insulin secretory granules (ISG) has never previously been thoroughly characterized. We characterized the phospholipid composition of ISG and mitochondria in pancreatic beta cells without and with glucose stimulation. The phospholipid/protein ratios of most phospholipids containing unsaturated fatty acids were higher in ISG than in whole cells and in mitochondria. The concentrations of negatively charged phospholipids, phosphatidylserine, and phosphatidylinositol in ISG were 5-fold higher than in the whole cell. In ISG phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, and sphingomyelin, fatty acids 12:0 and 14:0 were high, as were phosphatidylserine and phosphatidylinositol containing 18-carbon unsaturated FA. With glucose stimulation, the concentration of many ISG phosphatidylserines and phosphatidylinositols increased; unsaturated fatty acids in phosphatidylserine increased; and most phosphatidylethanolamines, phosphatidylcholines, sphingomyelins, and lysophosphatidylcholines were unchanged. Unsaturation and shorter fatty acid length in phospholipids facilitate curvature and fluidity of membranes, which favors fusion of membranes. Recent evidence suggests that negatively charged phospholipids, such as phosphatidylserine, act as coupling factors enhancing the interaction of positively charged regions in SNARE proteins in synaptic or secretory vesicle membrane lipid bilayers with positively charged regions in SNARE proteins in the plasma membrane lipid bilayer to facilitate docking of vesicles to the plasma membrane during exocytosis. The results indicate that ISG phospholipids are in a dynamic state and are consistent with the idea that changes in ISG phospholipids facilitate fusion of ISG with the plasma membrane-enhancing glucose-stimulated insulin exocytosis. PMID:25762724

  13. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells

    International Nuclear Information System (INIS)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng

    2015-01-01

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes. - Highlights: • TLX overexpression in MIN6 cell causes significant expression changes of 225 genes. • TLX overexpression promotes MIN6 cell proliferation and decreases cell apoptosis. • TLX overexpression does not cause impairment of insulin secretion.

  14. Nuclear orphan receptor TLX affects gene expression, proliferation and cell apoptosis in beta cells

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xiaoli; Xiong, Xiaokan; Dai, Zhe; Deng, Haohua; Sun, Li; Hu, Xuemei; Zhou, Feng; Xu, Yancheng, E-mail: oxyccc@163.com

    2015-12-04

    Nuclear orphan receptor TLX is an essential regulator of the growth of neural stem cells. However, its exact function in pancreatic islet cells is still unknown. In the present study, gene expression profiling analysis revealed that overexpression of TLX in beta cell line MIN6 causes suppression of 176 genes and upregulation of 49 genes, including a cadre of cell cycle, cell proliferation and cell death control genes, such as Btg2, Ddit3 and Gadd45a. We next examined the effects of TLX overexpression on proliferation, apoptosis and insulin secretion in MIN6 cells. Proliferation analysis using EdU assay showed that overexpression of TLX increased percentage of EdU-positive cells. Cell cycle and apoptosis analysis revealed that overexpression of TLX in MIN6 cells resulted in higher percentage of cells exiting G1 into S-phase, and a 58.8% decrease of cell apoptosis induced by 0.5 mM palmitate. Moreover, TLX overexpression did not cause impairment of insulin secretion. Together, we conclude that TLX is among factors capable of controlling beta cell proliferation and survival, which may serve as a target for the development of novel therapies for diabetes. - Highlights: • TLX overexpression in MIN6 cell causes significant expression changes of 225 genes. • TLX overexpression promotes MIN6 cell proliferation and decreases cell apoptosis. • TLX overexpression does not cause impairment of insulin secretion.

  15. An Abbreviated Protocol for In Vitro Generation of Functional Human Embryonic Stem Cell-Derived Beta-Like Cells.

    Directory of Open Access Journals (Sweden)

    Mohammad Massumi

    Full Text Available The ability to yield glucose-responsive pancreatic beta-cells from human pluripotent stem cells in vitro will facilitate the development of the cell replacement therapies for the treatment of Type 1 Diabetes. Here, through the sequential in vitro targeting of selected signaling pathways, we have developed an abbreviated five-stage protocol (25-30 days to generate human Embryonic Stem Cell-Derived Beta-like Cells (ES-DBCs. We showed that Geltrex, as an extracellular matrix, could support the generation of ES-DBCs more efficiently than that of the previously described culture systems. The activation of FGF and Retinoic Acid along with the inhibition of BMP, SHH and TGF-beta led to the generation of 75% NKX6.1+/NGN3+ Endocrine Progenitors. The inhibition of Notch and tyrosine kinase receptor AXL, and the treatment with Exendin-4 and T3 in the final stage resulted in 35% mono-hormonal insulin positive cells, 1% insulin and glucagon positive cells and 30% insulin and NKX6.1 co-expressing cells. Functionally, ES-DBCs were responsive to high glucose in static incubation and perifusion studies, and could secrete insulin in response to successive glucose stimulations. Mitochondrial metabolic flux analyses using Seahorse demonstrated that the ES-DBCs could efficiently metabolize glucose and generate intracellular signals to trigger insulin secretion. In conclusion, targeting selected signaling pathways for 25-30 days was sufficient to generate ES-DBCs in vitro. The ability of ES-DBCs to secrete insulin in response to glucose renders them a promising model for the in vitro screening of drugs, small molecules or genes that may have potential to influence beta-cell function.

  16. Apoptosis: Targets in Pancreatic Cancer

    Directory of Open Access Journals (Sweden)

    Kalthoff Holger

    2003-01-01

    Full Text Available Abstract Pancreatic adenocarcinoma is characterized by poor prognosis, because of late diagnosis and lack of response to chemo- and/or radiation therapies. Resistance to apoptosis mainly causes this insensitivity to conventional therapies. Apoptosis or programmed cell death is a central regulator of tissue homeostasis. Certain genetic disturbances of apoptotic signaling pathways have been found in carcinomas leading to tumor development and progression. In the past few years, the knowledge about the complex pathways of apoptosis has strongly increased and new therapeutic approaches based on this knowledge are being developed. This review will focus on the role of apoptotic proteins contributing to pancreatic cancer development and progression and will demonstrate possible targets to influence this deadly disease.

  17. ENDOCRINE PANCREATIC FUNCTION IN ACUTE PANCREATITIS

    Directory of Open Access Journals (Sweden)

    P. V. Novokhatny

    2014-02-01

    Full Text Available Introduction Among the organs of internal secretion pancreas has a special place thanks to active exocrine function and a wide range of physiological actions of produced hormones. Violations of endocrine pancreas arises in 6.5-38 % of patients with acute pancreatitis. However, there is still no clear understanding of the pathogenetic mechanisms of hormonal dysfunction of the pancreas in acute pancreatitis, there is no uniform algorithms for its correction. Aim of the research was to study the endocrine function of pancreas in acute pancreatitis. To define the role of endocrine pancreatic function in the etiology and pathogenesis of the acute pancreatitis. To assess the prospects of the use of pancreatic hormones in the treatment and predicting the outcomes of acute pancreatitis. Materials and methods of the research Survey of publications in specialized periodical medical journals, PubMed sources developed by the National Center for Biotechnology Information. Search in PubMed was carried out in the following databases: MEDLINE, Pre MEDLINE. Results of the research. In a significant proportion of patients who recovered from acute pancreatitis, exocrine and endocrine functional impairments were found. This finding was not detected only in patients after severe acute pancreatitis. Routine evaluation of pancreatic function after acute pancreatitis should be considered. The comparative analysis of the synthetic analogues (somatostatin, calcitonin, leu-enkefalin-dalargin influence on the glucose metabolism of rats in acute pancreatitis of was made. Physiological reaction of beta-cells is preserved in infusion of somatostatin. However, infusion of calcitonin results in the distortion of counterregulatory action of insulin and glucagon. It was detected that pancreatic renin-angiotensin system is markedly activated in the experimental rat models of chronic hypoxia and acute pancreatitis. The activation of the pancreatic renin-angiotensin system by

  18. Beta Lactamase Producing Clostridium perfringens Bacteremia in an Elderly Man with Acute Pancreatitis

    Directory of Open Access Journals (Sweden)

    Rashmi Mishra

    2016-01-01

    Full Text Available Clostridium perfringens bacteremia is associated with adverse outcomes. Known risk factors include chronic kidney disease, malignancy, diabetes mellitus, and gastrointestinal disease. We present a 74-year-old man admitted with confusion, vomiting, and abdominal pain. Exam revealed tachycardia, hypotension, lethargy, distended abdomen, and cold extremities. He required intubation and aggressive resuscitation for septic shock. Laboratory data showed leukocytosis, metabolic acidosis, acute kidney injury, and elevated lipase. CT scan of abdomen revealed acute pancreatitis and small bowel ileus. He was started on vancomycin and piperacillin-tazobactam. Initial blood cultures were positive for C. perfringens on day five. Metronidazole and clindamycin were added to the regimen. Repeat CT (day 7 revealed pancreatic necrosis. The patient developed profound circulatory shock requiring multiple vasopressors, renal failure requiring dialysis, and bacteremia with vancomycin-resistant enterococci. Hemodynamic instability precluded surgical intervention and he succumbed to multiorgan failure. Interestingly, our isolate was beta lactamase producing. We review the epidemiology, risk factors, presentation, and management of C. perfringens bacteremia. This case indicates a need for high clinical suspicion for clostridial sepsis and that extended spectrum beta lactam antibiotic coverage may be inadequate and should be supplemented with use of clindamycin or metronidazole if culture is positive, until sensitivities are known.

  19. Reference intervals for glucose, beta-cell polypeptides and counterregulatory factors during prolonged fasting

    DEFF Research Database (Denmark)

    Højlund, Kurt; Wildner-Christensen, M; Eshøj, O

    2001-01-01

    To establish reference intervals for the pancreatic beta-cell response and the counterregulatory hormone response to prolonged fasting, we studied 33 healthy subjects (16 males, 17 females) during a 72-h fast. Glucose, insulin, C-peptide, and proinsulin levels decreased (P ... of counterregulatory factors increased during the fast [P fasting (P ... decreased from the second to third day of fasting (P = 0.03). Males had higher glucose and glucagon levels and lower FFA levels during the fast (P

  20. Expression of transforming growth factor beta (TGF beta) receptors and expression of TGF beta 1, TGF beta 2 and TGF beta 3 in human small cell lung cancer cell lines

    DEFF Research Database (Denmark)

    Damstrup, L; Rygaard, K; Spang-Thomsen, M

    1993-01-01

    A panel of 21 small cell lung cancer cell (SCLC) lines were examined for the presence of Transforming growth factor beta receptors (TGF beta-r) and the expression of TGF beta mRNAs. By the radioreceptor assay we found high affinity receptors to be expressed in six cell lines. scatchard analysis......(r) = 65,000 and 90,000 and the betaglycan (type III) with M(r) = 280,000. Northern blotting showed expression of TGF beta 1 mRNA in ten, TGF beta 2 mRNA in two and TGF beta 3 mRNA in seven cell lines. Our results provide, for the first time, evidence that a large proportion of a broad panel of SCLC cell...... lines express TGF beta-receptors and also produce TGF beta mRNAs....

  1. Pancreatic β-Cell Electrical Activity and Insulin Secretion: of Mice and Men

    Science.gov (United States)

    Rorsman, Patrik; Ashcroft, Frances M

    2018-01-01

    The pancreatic β-cell plays a key role in glucose homeostasis by secreting insulin, the only hormone capable of lowering the blood glucose concentration. Impaired insulin secretion results in the chronic hyperglycaemia that characterizes type 2 diabetes (T2DM), which currently afflicts >450 million people worldwide. The healthy β-cell acts as a glucose sensor matching its output to the circulating glucose concentration. It does so via metabolically induced changes in electrical activity, which culminate in an increase in the cytoplasmic Ca2+ concentration and initiation of Ca2+-dependent exocytosis of insulin-containing secretory granules. Here, we review recent advances in our understanding of the β-cell transcriptome, electrical activity and insulin exocytosis. We highlight salient differences between mouse and human β-cells, provide models of how the different ion channels contribute to their electrical activity and insulin secretion, and conclude by discussing how these processes become perturbed in T2DM. PMID:29212789

  2. Atypical antipsychotics and glucose homeostasis.

    Science.gov (United States)

    Bergman, Richard N; Ader, Marilyn

    2005-04-01

    needed. A major problem in assessing drug effects is that psychiatric disease itself can cause many of the manifestations leading to diabetes, including weight gain and sedentary lifestyle. While studies in healthy subjects are limited and inconclusive, studies in animal models are more revealing. In the conscious canine model, some atypical antipsychotics cause adiposity, including visceral obesity, a strong risk factor for the metabolic syndrome. Furthermore, while few studies have examined effects of antipsychotics on pancreatic beta-cell function, canine studies demonstrate that expected beta-cell compensation for insulin resistance may be reduced or even eliminated with these agents. Atypical antipsychotics have been shown to contribute to weight gain, which may well reflect increased body fat deposition. Such increased fat is known to cause resistance to insulin action, although more information regarding effect on insulin action is needed. The effect of these drugs on fat distribution has been clearly shown in animal models. It is known that the normal response to insulin resistance is compensatory hyperinsulinemia, which may prevent diabetes. In animals, there is evidence that the hyperinsulinemic compensation is inadequate in the face of atypical antipsychotic agents. It remains to be examined whether failure of adequate pancreatic beta-cell compensation for insulin resistance plays a central role in the pathogenesis of diabetes associated with this class of drugs.

  3. Pancreatic β-cell regeneration: Facultative or dedicated progenitors?

    Science.gov (United States)

    Afelik, Solomon; Rovira, Meritxell

    2017-04-15

    The adult pancreas is only capable of limited regeneration. Unlike highly regenerative tissues such as the skin, intestinal crypts and hematopoietic system, no dedicated adult stem cells or stem cell niche have so far been identified within the adult pancreas. New β cells have been shown to form in the adult pancreas, in response to high physiological demand or experimental β-cell ablation, mostly by replication of existing β cells. The possibility that new β cells are formed from other sources is currently a point of major controversy. Under particular injury conditions, fully differentiated pancreatic duct and acinar cells have been shown to dedifferentiate into a progenitor-like state, however the extent, to which ductal, acinar or other endocrine cells contribute to restoring pancreatic β-cell mass remains to be resolved. In this review we focus on regenerative events in the pancreas with emphasis on the restoration of β-cell mass. We present an overview of regenerative responses noted within the different pancreatic lineages, following injury. We also highlight the intrinsic plasticity of the adult pancreas that allows for inter-conversion of fully differentiated pancreatic lineages through manipulation of few genes or growth factors. Taken together, evidence from a number of studies suggest that differentiated pancreatic lineages could act as facultative progenitor cells, but the extent to which these contribute to β-cell regeneration in vivo is still a matter of contention. Copyright © 2016. Published by Elsevier B.V.

  4. Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

    International Nuclear Information System (INIS)

    Rashid, Kahkashan; Sil, Parames C.

    2015-01-01

    The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65 mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100 mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus. - Highlights: • STZ induced cellular stress plays a vital role in pancreatic dysfunction. • Cellular stress causes inflammation, pancreatic islet cell death and diabetes. • Deregulation of Nrf-2

  5. Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Kahkashan; Sil, Parames C., E-mail: parames@jcbose.ac.in

    2015-02-01

    The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65 mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100 mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus. - Highlights: • STZ induced cellular stress plays a vital role in pancreatic dysfunction. • Cellular stress causes inflammation, pancreatic islet cell death and diabetes. • Deregulation of Nrf-2

  6. FGF7 and cell density are required for final differentiation of pancreatic amylase-positive cells from human ES cells.

    Science.gov (United States)

    Takizawa-Shirasawa, Sakiko; Yoshie, Susumu; Yue, Fengming; Mogi, Akimi; Yokoyama, Tadayuki; Tomotsune, Daihachiro; Sasaki, Katsunori

    2013-12-01

    The major molecular signals of pancreatic exocrine development are largely unknown. We examine the role of fibroblast growth factor 7 (FGF7) in the final induction of pancreatic amylase-containing exocrine cells from induced-pancreatic progenitor cells derived from human embryonic stem (hES) cells. Our protocol consisted in three steps: Step I, differentiation of definitive endoderm (DE) by activin A treatment of hES cell colonies; Step II, differentiation of pancreatic progenitor cells by re-plating of the cells of Step I onto 24-well plates at high density and stimulation with all-trans retinoic acid; Step III, differentiation of pancreatic exocrine cells with a combination of FGF7, glucagon-like peptide 1 and nicotinamide. The expression levels of pancreatic endodermal markers such as Foxa2, Sox17 and gut tube endoderm marker HNF1β were up-regulated in both Step I and II. Moreover, in Step III, the induced cells expressed pancreatic markers such as amylase, carboxypeptidase A and chymotrypsinogen B, which were similar to those in normal human pancreas. From day 8 in Step III, cells immunohistochemically positive for amylase and for carboxypeptidase A, a pancreatic exocrine cell product, were induced by FGF7. Pancreatic progenitor Pdx1-positive cells were localized in proximity to the amylase-positive cells. In the absence of FGF7, few amylase-positive cells were identified. Thus, our three-step culture protocol for human ES cells effectively induces the differentiation of amylase- and carboxypeptidase-A-containing pancreatic exocrine cells.

  7. Characterization of stimulus-secretion coupling in the human pancreatic EndoC-βH1 beta cell line.

    Directory of Open Access Journals (Sweden)

    Lotta E Andersson

    Full Text Available Studies on beta cell metabolism are often conducted in rodent beta cell lines due to the lack of stable human beta cell lines. Recently, a human cell line, EndoC-βH1, was generated. Here we investigate stimulus-secretion coupling in this cell line, and compare it with that in the rat beta cell line, INS-1 832/13, and human islets.Cells were exposed to glucose and pyruvate. Insulin secretion and content (radioimmunoassay, gene expression (Gene Chip array, metabolite levels (GC/MS, respiration (Seahorse XF24 Extracellular Flux Analyzer, glucose utilization (radiometric, lactate release (enzymatic colorimetric, ATP levels (enzymatic bioluminescence and plasma membrane potential and cytoplasmic Ca2+ responses (microfluorometry were measured. Metabolite levels, respiration and insulin secretion were examined in human islets.Glucose increased insulin release, glucose utilization, raised ATP production and respiratory rates in both lines, and pyruvate increased insulin secretion and respiration. EndoC-βH1 cells exhibited higher insulin secretion, while plasma membrane depolarization was attenuated, and neither glucose nor pyruvate induced oscillations in intracellular calcium concentration or plasma membrane potential. Metabolite profiling revealed that glycolytic and TCA-cycle intermediate levels increased in response to glucose in both cell lines, but responses were weaker in EndoC-βH1 cells, similar to those observed in human islets. Respiration in EndoC-βH1 cells was more similar to that in human islets than in INS-1 832/13 cells.Functions associated with early stimulus-secretion coupling, with the exception of plasma membrane potential and Ca2+ oscillations, were similar in the two cell lines; insulin secretion, respiration and metabolite responses were similar in EndoC-βH1 cells and human islets. While both cell lines are suitable in vitro models, with the caveat of replicating key findings in isolated islets, EndoC-βH1 cells have the

  8. Clinical characteristics and beta cell function in Chinese patients with newly diagnosed type 2 diabetes mellitus with different levels of serum triglyceride.

    Science.gov (United States)

    Zheng, Shuang; Zhou, Huan; Han, Tingting; Li, Yangxue; Zhang, Yao; Liu, Wei; Hu, Yaomin

    2015-04-29

    To explore clinical characteristics and beta cell function in Chinese patients with newly diagnosed drug naive type 2 diabetes mellitus (T2DM) with different levels of serum triglyceride (TG). Patients with newly diagnosed T2DM (n = 624) were enrolled and divided into different groups according to levels of serum TG. All patients underwent oral glucose tolerance tests and insulin releasing tests. Demographic data, lipid profiles, glucose levels, and insulin profiles were compared between different groups. Basic insulin secretion function index (homeostasis model assessment for beta cell function index, HOMA-β), modified beta cell function index (MBCI), glucose disposition indices (DI), and early insulin secretion function index (insulinogenic index, IGI) were used to evaluate the beta cell function. Patients of newly diagnosed T2DM with hypertriglyceridemia were younger, fatter and had worse lipid profiles, glucose profiles, and high insulin levels than those with normal TG. There is no difference in early phase insulin secretion among groups of newly diagnosed T2DM patients with different TG levels. The basal beta cell function (HOMA-β and MBCI) initially increased along rising TG levels and then decreased as the TG levels rose further. The insulin sensitivity was relatively high in patients with a low level of TG and low with a high level of TG. Hypertriglyceridemia influences clinical characteristics and β cell function of Chinese patients with newly diagnosed T2DM. A better management of dyslipidemia may, to some extent, reduce the effect of lipotoxicity, thereby improving glucose homeostasis in patients with newly diagnosed T2DM.

  9. miR-146a Suppresses Invasion of Pancreatic Cancer Cells

    Science.gov (United States)

    Li, Yiwei; VandenBoom, Timothy G.; Wang, Zhiwei; Kong, Dejuan; Ali, Shadan; Philip, Philip A.; Sarkar, Fazlul H.

    2010-01-01

    The aggressive course of pancreatic cancer is believed to reflect its unusually invasive and metastatic nature, which is associated with epidermal growth factor receptor (EGFR) overexpression and NF-κB activation. MicroRNAs (miRNA) have been implicated in the regulation of various pathobiological processes in cancer, including metastasis in pancreatic cancer and in other human malignancies. In this study, we report lower expression of miR-146a in pancreatic cancer cells compared with normal human pancreatic duct epithelial cells. Reexpression of miR-146a inhibited the invasive capacity of pancreatic cancer cells with concomitant downregulation of EGFR and the NF-κB regulatory kinase interleukin 1 receptor–associated kinase 1 (IRAK-1). Cellular mechanism studies revealed crosstalk between EGFR, IRAK-1, IκBα, NF-κB, and MTA-2, a transcription factor that regulates metastasis. Treatment of pancreatic cancer cells with the natural products 3,3′-diinodolylmethane (DIM) or isoflavone, which increased miR-146a expression, caused a downregulation of EGFR, MTA-2, IRAK-1, and NF-κB, resulting in an inhibition of pancreatic cancer cell invasion. Our findings reveal DIM and isoflavone as nontoxic activators of a miRNA that can block pancreatic cancer cell invasion and metastasis, offering starting points to design novel anticancer agents. PMID:20124483

  10. Stem cell-based approach in diabetes and pancreatic cancer management

    Directory of Open Access Journals (Sweden)

    Yi-Zhou Jiang

    2017-01-01

    Full Text Available Stem cell-mediated therapy is a promising strategy for treating pancreatic diseases such as Type-1 diabetes (T1D and pancreatic cancers. Although islet transplantation has been reported to be an effective diabetes therapy, its worldwide application is extremely limited due to the shortage of donor islets and immune rejection problems. Stem cell-based approach for islet neogenesis in vivo could provide a promising alternative source of islets for treating diabetes. On the other hand, targeting the cancer stem cells could be very effective for the treatment of pancreatic cancers. In this review, we focused on the present progress in the field of adult pancreatic stem cells, stem cell-mediated strategies for treating T1D, and pancreatic cancer stem cells, while discussing of the possible challenges involved in them.

  11. Effects of the hypoglycaemic drugs repaglinide and glibenclamide on ATP-sensitive potassium-channels and cytosolic calcium levels in beta TC3 cells and rat pancreatic beta cells

    DEFF Research Database (Denmark)

    Gromada, J; Dissing, S; Kofod, Hans

    1995-01-01

    The present study demonstrates the action of the hypoglycaemic drugs repaglinide and glibenclamide in cultured newborn rat islet cells and mouse beta TC3 cells. In cell-attached membrane patches of newborn rat islet cells repaglinide (10 nmol/l) and glibenclamide (20 nmol/l) decrease the open pro...

  12. Characterization of phospholipids in insulin secretory granules and mitochondria in pancreatic beta cells and their changes with glucose stimulation.

    Science.gov (United States)

    MacDonald, Michael J; Ade, Lacmbouh; Ntambi, James M; Ansari, Israr-Ul H; Stoker, Scott W

    2015-04-24

    The lipid composition of insulin secretory granules (ISG) has never previously been thoroughly characterized. We characterized the phospholipid composition of ISG and mitochondria in pancreatic beta cells without and with glucose stimulation. The phospholipid/protein ratios of most phospholipids containing unsaturated fatty acids were higher in ISG than in whole cells and in mitochondria. The concentrations of negatively charged phospholipids, phosphatidylserine, and phosphatidylinositol in ISG were 5-fold higher than in the whole cell. In ISG phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, and sphingomyelin, fatty acids 12:0 and 14:0 were high, as were phosphatidylserine and phosphatidylinositol containing 18-carbon unsaturated FA. With glucose stimulation, the concentration of many ISG phosphatidylserines and phosphatidylinositols increased; unsaturated fatty acids in phosphatidylserine increased; and most phosphatidylethanolamines, phosphatidylcholines, sphingomyelins, and lysophosphatidylcholines were unchanged. Unsaturation and shorter fatty acid length in phospholipids facilitate curvature and fluidity of membranes, which favors fusion of membranes. Recent evidence suggests that negatively charged phospholipids, such as phosphatidylserine, act as coupling factors enhancing the interaction of positively charged regions in SNARE proteins in synaptic or secretory vesicle membrane lipid bilayers with positively charged regions in SNARE proteins in the plasma membrane lipid bilayer to facilitate docking of vesicles to the plasma membrane during exocytosis. The results indicate that ISG phospholipids are in a dynamic state and are consistent with the idea that changes in ISG phospholipids facilitate fusion of ISG with the plasma membrane-enhancing glucose-stimulated insulin exocytosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Echovirus 6 Infects Human Exocrine and Endocrine Pancreatic Cells and Induces Pro-Inflammatory Innate Immune Response

    Directory of Open Access Journals (Sweden)

    Luis Sarmiento

    2017-01-01

    Full Text Available Human enteroviruses (HEV, especially coxsackievirus serotype B (CVB and echovirus (E, have been associated with diseases of both the exocrine and endocrine pancreas, but so far evidence on HEV infection in human pancreas has been reported only in islets and ductal cells. This study aimed to investigate the capability of echovirus strains to infect human exocrine and endocrine pancreatic cells. Infection of explanted human islets and exocrine cells with seven field strains of E6 caused cytopathic effect, virus titer increase and production of HEV protein VP1 in both cell types. Virus particles were found in islets and acinar cells infected with E6. No cytopathic effect or infectious progeny production was observed in exocrine cells exposed to the beta cell-tropic strains of E16 and E30. Endocrine cells responded to E6, E16 and E30 by upregulating the transcription of interferon-induced with helicase C domain 1 (IF1H1, 2'-5'-oligoadenylate synthetase 1 (OAS1, interferon-β (IFN-β, chemokine (C–X–C motif ligand 10 (CXCL10 and chemokine (C–C motif ligand 5 (CCL5. Echovirus 6, but not E16 or E30, led to increased transcription of these genes in exocrine cells. These data demonstrate for the first time that human exocrine cells represent a target for E6 infection and suggest that certain HEV serotypes can replicate in human pancreatic exocrine cells, while the pancreatic endocrine cells are permissive to a wider range of HEV.

  14. Tissue-specific methylation of human insulin gene and PCR assay for monitoring beta cell death.

    Directory of Open Access Journals (Sweden)

    Mohamed I Husseiny

    Full Text Available The onset of metabolic dysregulation in type 1 diabetes (T1D occurs after autoimmune destruction of the majority of pancreatic insulin-producing beta cells. We previously demonstrated that the DNA encoding the insulin gene is uniquely unmethylated in these cells and then developed a methylation-specific PCR (MSP assay to identify circulating beta cell DNA in streptozotocin-treated mice prior to the rise in blood glucose. The current study extends to autoimmune non-obese diabetic (NOD mice and humans, showing in NOD mice that beta cell death occurs six weeks before the rise in blood sugar and coincides with the onset of islet infiltration by immune cells, demonstrating the utility of MSP for monitoring T1D. We previously reported unique patterns of methylation of the human insulin gene, and now extend this to other human tissues. The methylation patterns of the human insulin promoter, intron 1, exon 2, and intron 2 were determined in several normal human tissues. Similar to our previous report, the human insulin promoter was unmethylated in beta cells, but methylated in all other tissues tested. In contrast, intron 1, exon 2 and intron 2 did not exhibit any tissue-specific DNA methylation pattern. Subsequently, a human MSP assay was developed based on the methylation pattern of the insulin promoter and human islet DNA was successfully detected in circulation of T1D patients after islet transplantation therapy. Signal levels of normal controls and pre-transplant samples were shown to be similar, but increased dramatically after islet transplantation. In plasma the signal declines with time but in whole blood remains elevated for at least two weeks, indicating that association of beta cell DNA with blood cells prolongs the signal. This assay provides an effective method to monitor beta cell destruction in early T1D and in islet transplantation therapy.

  15. Pancreatic iron stores assessed by magnetic resonance imaging (MRI) in beta thalassemic patients

    International Nuclear Information System (INIS)

    Feitosa de Assis, Reijâne Alves; Ribeiro, Andreza Alice; Kay, Fernando Uliana; Rosemberg, Laércio Alberto; Nomura, Cesar Higa; Loggetto, Sandra Regina; Araujo, Aderson S.; Fabron Junior, Antonio; Pinheiro de Almeida Veríssimo, Mônica; Baldanzi, Giorgio Roberto; Espósito, Breno Pannia; Baroni, Ronaldo Hueb; Wood, John C.; Hamerschlak, Nelson

    2012-01-01

    Purpose: To assess the correlation between MRI findings of the pancreas with those of the heart and liver in patients with beta thalassemia; to compare the pancreas T2* MRI results with glucose and ferritin levels and labile plasma iron (LPI). Materials and methods: We retrospectively evaluated chronically transfused patients, testing glucose with enzymatic tests, serum ferritin with chemiluminescence, LPI with cellular fluorescence, and T2* MRI to assess iron content in the heart, liver, and pancreas. MRI results were compared with one another and with serum glucose, ferritin, and LPI. Liver iron concentration (LIC) was determined in 11 patients’ liver biopsies by atomic absorption spectrometry. Results: 289 MRI studies were available from 115 patients during the period studied. 9.4% of patients had overt diabetes and an additional 16% of patients had impaired fasting glucose. Both pancreatic and cardiac R2* had predictive power (p 2 = 0.20, p 2 = 0.09, p 2 = 0.14, p 2 = 0.03, p 2 of 0.91. Conclusions: Pancreatic iron overload can be assessed by MRI, but siderosis in other organs did not correlate significantly with pancreatic hemosiderosis.

  16. Computed tomography findings of pancreatic metastases from renal cell carcinoma

    International Nuclear Information System (INIS)

    Prando, Adilson

    2008-01-01

    Objective: To present computed tomography findings observed in four patients submitted to radical nephrectomy for renal cell carcinoma who developed pancreatic metastases afterwards. Materials and methods: The four patients underwent radical nephrectomy for stage Tz1 (n=2) and stage T3a (n=2) renal cell carcinoma. The mean interval between nephrectomy and detection of pancreatic metastases was eight years. Two asymptomatic patients presented with solitary pancreatic metastases (confined to the pancreas). Two symptomatic patients presented with single and multiple pancreatic metastases, both with tumor recurrence in the contralateral kidney. Results: Computed tomography studies demonstrated pancreatic metastases as solitary (n=2), single (n=1) or multiple (n=1) hypervascular lesions. Partial pancreatectomy was performed in two patients with solitary pancreatic metastases and both are free of disease at four and two years after surgery. Conclusion: Pancreatic metastases from renal cell carcinoma are rare and can occur many years after the primary tumor presentation. Multiple pancreatic metastases and pancreatic metastases associated with tumor recurrence in the contralateral kidney are uncommon. Usually, on computed tomography images pancreatic metastases are visualized as solitary hypervascular lesions, simulating isletcell tumors. Surgical management should be considered for patients with solitary pancreatic lesions. (author)

  17. Computed tomography findings of pancreatic metastases from renal cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Prando, Adilson [Hospital Vera Cruz, Campinas, SP (Brazil). Dept. of Radiology and Imaging Diagnosis]. E-mail: adilson.prando@gmail.com

    2008-07-15

    Objective: To present computed tomography findings observed in four patients submitted to radical nephrectomy for renal cell carcinoma who developed pancreatic metastases afterwards. Materials and methods: The four patients underwent radical nephrectomy for stage Tz1 (n=2) and stage T3a (n=2) renal cell carcinoma. The mean interval between nephrectomy and detection of pancreatic metastases was eight years. Two asymptomatic patients presented with solitary pancreatic metastases (confined to the pancreas). Two symptomatic patients presented with single and multiple pancreatic metastases, both with tumor recurrence in the contralateral kidney. Results: Computed tomography studies demonstrated pancreatic metastases as solitary (n=2), single (n=1) or multiple (n=1) hypervascular lesions. Partial pancreatectomy was performed in two patients with solitary pancreatic metastases and both are free of disease at four and two years after surgery. Conclusion: Pancreatic metastases from renal cell carcinoma are rare and can occur many years after the primary tumor presentation. Multiple pancreatic metastases and pancreatic metastases associated with tumor recurrence in the contralateral kidney are uncommon. Usually, on computed tomography images pancreatic metastases are visualized as solitary hypervascular lesions, simulating isletcell tumors. Surgical management should be considered for patients with solitary pancreatic lesions. (author)

  18. Secondary pancreatic involvement by a diffuse large B-cell lymphoma presenting as acute pancreatitis

    Institute of Scientific and Technical Information of China (English)

    M Wasif Saif; Sapna Khubchandani; Marek Walczak

    2007-01-01

    Diffuse large B-cell lymphoma is the most common type of non-Hodgkin's lymphoma. More than 50% of patients have some site of extra-nodal involvement at diagnosis,including the gastrointestinal tract and bone marrow.However, a diffuse large B-cell lymphoma presenting as acute pancreatitis is rare. A 57-year-old female presented with abdominal pain and matted lymph nodes in her axilla. She was admitted with a diagnosis of acute pancreatitis. Abdominal computed tomography (CT) scan showed diffusely enlarged pancreas due to infiltrative neoplasm and peripancreatic lymphadenopathy. Biopsy of the axillary mass revealed a large B-cell lymphoma.The patient was classified as stage Ⅳ, based on the Ann Arbor Classification, and as having a high-risk lymphoma,based on the International Prognostic Index. She was started on chemotherapy with CHOP (cyclophosphamide,doxorubicin, vincristine and prednisone). Within a week after chemotherapy, the patient's abdominal pain resolved. Follow-up CT scan of the abdomen revealed a marked decrease in the size of the pancreas and peripancreatic lymphadenopathy. A literature search revealed only seven cases of primary involvement of the pancreas in B-cell lymphoma presenting as acute pancreatitis. However, only one case of secondary pancreatic involvement by B-cell lymphoma presenting as acute pancreatitis has been published. Our case appears to be the second report of such a manifestation.Both cases responded well to chemotherapy.

  19. Simulated Microgravity Reduces TNF-Alpha Activity, Suppresses Glucose Uptake and Enhances Arginine Flux in Pancreatic Islets of Langerhans

    Science.gov (United States)

    Tobin, Brian W.; Leeper-Woodford, Sandra K.; Hashemi, Brian B.; Smith, Scott M.; Sams, Clarence F.; Paloski, W. H. (Technical Monitor)

    2000-01-01

    The present studies were designed to determine effects of microgravity upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF - alpha) activity and indices of insulin and fuel homeostasis of pancreatic islets of Langerhans. Islets (1726+/-117,150 u IEU) from Wistar Furth rats were treated as: 1) HARV (High Aspect Ratio Vessel cell culture) , 2) HARV plus LPS 3) static culture, 4) static culture plus LPS TNF-alpha (L929 cytotoxicity assay) was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (palpha production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV paradigm. These alterations in fuel homeostasis may be promulgated by gravity averaged cell culture methods or by three dimensional cell assembly.

  20. Pancreatic Stellate Cells : A Starring Role in Normal and Diseased Pancreas

    Directory of Open Access Journals (Sweden)

    Minoti eApte

    2012-08-01

    Full Text Available While the morphology and function of cells of the exocrine and endocrine pancreas have been studied over several centuries, one important cell type in the gland, the pancreatic stellate cell (PSC, had remained undiscovered until as recently as twenty years ago. Even after its first description in 1982, it was to be another 16 years before its biology could begin to be studied, because it was only in 1998 that methods were developed to isolate and culture PSCs from rodent and human pancreas. PSCs are now known to play a critical role in pancreatic fibrosis, a consistent histological feature of two major diseases of the pancreas - chronic pancreatitis and pancreatic cancer. In health, PSCs maintain normal tissue architecture via regulation of the synthesis and degradation of extracellular matrix (ECM proteins. Recent studies have also implied other additional functions for PSCs as progenitor cells, immune cells or intermediaries in exocrine pancreatic secretion in humans.During pancreatic injury, PSCs transform from their quiescent phase into an activated, myofibroblast-like phenotype that secretes excessive amounts of ECM proteins leading to the fibrosis of chronic pancreatitis and pancreatic cancer. An ever increasing number of factors that stimulate and/or inhibit PSC activation via paracrine and autocrine pathways are being identified and characterized. It is also now established that PSCs interact closely with pancreatic cancer cells to facilitate cancer progression. Based on these findings, several therapeutic strategies have been examined in experimental models of chronic pancreatitis as well as pancreatic cancer, in a bid to inhibit/retard PSC activation and thereby alleviate chronic pancreatitis or reduce tumour growth in pancreatic cancer. The challenge that remains is to translate these pre-clinical developments into clinically applicable treatments for patients with chronic pancreatitis and pancreatic cancer.

  1. Acinar-to-Ductal Metaplasia Induced by Transforming Growth Factor Beta Facilitates KRASG12D-driven Pancreatic TumorigenesisSummary

    Directory of Open Access Journals (Sweden)

    Nicolas Chuvin

    2017-09-01

    Full Text Available Background & Aims: Transforming growth factor beta (TGFβ acts either as a tumor suppressor or as an oncogene, depending on the cellular context and time of activation. TGFβ activates the canonical SMAD pathway through its interaction with the serine/threonine kinase type I and II heterotetrameric receptors. Previous studies investigating TGFβ-mediated signaling in the pancreas relied either on loss-of-function approaches or on ligand overexpression, and its effects on acinar cells have so far remained elusive. Methods: We developed a transgenic mouse model allowing tamoxifen-inducible and Cre-mediated conditional activation of a constitutively active type I TGFβ receptor (TβRICA in the pancreatic acinar compartment. Results: We observed that TβRICA expression induced acinar-to-ductal metaplasia (ADM reprogramming, eventually facilitating the onset of KRASG12D-induced pre-cancerous pancreatic intraepithelial neoplasia. This phenotype was characterized by the cellular activation of apoptosis and dedifferentiation, two hallmarks of ADM, whereas at the molecular level, we evidenced a modulation in the expression of transcription factors such as Hnf1β, Sox9, and Hes1. Conclusions: We demonstrate that TGFβ pathway activation plays a crucial role in pancreatic tumor initiation through its capacity to induce ADM, providing a favorable environment for KRASG12D-dependent carcinogenesis. Such findings are highly relevant for the development of early detection markers and of potentially novel treatments for pancreatic cancer patients. Keywords: Pancreas, Cancer, TGFβ, Acinar-to-Ductal Metaplasia, KRASG12D

  2. Ginkgo Biloba Extract Kaempferol Inhibits Cell Proliferation and Induces Apoptosis in Pancreatic Cancer Cells

    Science.gov (United States)

    Zhang, Yuqing; Chen, Aaron Y.; Li, Min; Chen, Changyi; Yao, Qizhi

    2010-01-01

    Background Kaempferol is one of the most important constituents in ginkgo flavonoids. Recent studies indicate kaempferol may have anti-tumor activities. The objective in this study was to determine the effect and mechanisms of kaempferol on pancreatic cancer cell proliferation and apoptosis. Materials and Methods Pancreatic cancer cell lines MIA PaCa-2 and Panc-1 were treated with Kampferol, and the inhibitory effects of kaempferol on pancreatic cancer cell proliferation were examined by direct cell counting, 3H-thymidine incorporation and MTS assay. Lactate dehydrogenase (LDH) release from cells was determined as an index of cytotoxicity. Apoptosis was analyzed by TUNEL assay. Results Upon the treatment with 70 μM kaempferol for 4 days, MIA PaCa-2 cell proliferation was significantly inhibited by 79% and 45.7% as determined by direct cell counting and MTS assay, respectively, compared with control cells (Pkaempferol significantly inhibited Panc-1 cell proliferation. Kaempferol treatment also significantly reduced 3H-thymidine incorporation in both MIA PaCa-2 and Panc-1 cells. Combination treatment of low concentrations of kaempferol and 5-fluorouracil (5-FU) showed an additive effect on the inhibition of MIA PaCa-2 cell proliferation. Furthermore, kaempferol had a significantly less cytotoxicity than 5-FU in normal human pancreatic ductal epithelial cells (P=0.029). In both MIA PaCa-2 and Panc-1 cells, apoptotic cell population was increased when treated with kaempferol in a concentration-dependent manner. Conclusions Ginkgo biloba extract kaempferol effectively inhibits pancreatic cancer cell proliferation and induces cancer cell apoptosis, which may sensitize pancreatic tumor cells to chemotherapy. Kaempferol may have clinical applications as adjuvant therapy in the treatment of pancreatic cancer. PMID:18570926

  3. In vivo and in vitro evaluation of the effects of Urtica dioica and swimming activity on diabetic factors and pancreatic beta cells.

    Science.gov (United States)

    Ranjbari, Abbas; Azarbayjani, Mohammad Ali; Yusof, Ashril; Halim Mokhtar, Abdul; Akbarzadeh, Samad; Ibrahim, Mohamed Yousif; Tarverdizadeh, Bahman; Farzadinia, Parviz; Hajiaghaee, Reza; Dehghan, Firouzeh

    2016-03-15

    Urtica dioica (UD) has been identified as a traditional herbal medicine. This study aimed to investigate the effect of UD extract and swimming activity on diabetic parameters through in vivo and in vitro experiments. Adult WKY male rats were randomly distributed in nine groups: intact control, diabetic control, diabetic + 625 mg/kg, 1.25 g/kg UD, diabetic + 100 mg/kg Metformin, diabetic + swimming, diabetic + swimming 625 mg/kg, 1.25 g/kg UD, and diabetic +100 mg/kg Metformin + swimming. The hearts of the animals were punctured, and blood samples were collected for biochemical analysis. The entire pancreas was exposed for histologic examination. The effect of UD on insulin secretion by RIN-5F cells in 6.25 or 12.5 mM glucose dose was examined. Glucose uptake by cultured L6 myotubes was determined. The serum glucose concentration decreased, the insulin resistance and insulin sensitivity significantly increased in treated groups. These changes were more pronounced in the group that received UD extract and swimming training. Regeneration and less beta cell damage of Langerhans islets were observed in the treated groups. UD treatment increased insulin secretion in the RIN-5F cells and glucose uptake in the L6 myotubes cells. Swimming exercises accompanied by consuming UD aqueous extracts effectively improved diabetic parameters, repaired pancreatic tissues in streptozotocin-induced diabetics in vivo, and increased glucose uptake or insulin in UD-treated cells in vitro.

  4. Pancreatic acinar cells-derived cyclophilin A promotes pancreatic damage by activating NF-κB pathway in experimental pancreatitis

    International Nuclear Information System (INIS)

    Yu, Ge; Wan, Rong; Hu, Yanling; Ni, Jianbo; Yin, Guojian; Xing, Miao; Shen, Jie; Tang, Maochun; Chen, Congying; Fan, Yuting; Xiao, Wenqin; Zhao, Yan; Wang, Xingpeng

    2014-01-01

    Highlights: • CypA is upregulated in experimental pancreatitis. • CCK induces expression and release of CypA in acinar cell in vitro. • rCypA aggravates CCK-induced acinar cell death and inflammatory cytokine production. • rCypA activates the NF-κB pathway in acinar cells in vitro. - Abstract: Inflammation triggered by necrotic acinar cells contributes to the pathophysiology of acute pancreatitis (AP), but its precise mechanism remains unclear. Recent studies have shown that Cyclophilin A (CypA) released from necrotic cells is involved in the pathogenesis of several inflammatory diseases. We therefore investigated the role of CypA in experimental AP induced by administration of sodium taurocholate (STC). CypA was markedly upregulated and widely expressed in disrupted acinar cells, infiltrated inflammatory cells, and tubular complexes. In vitro, it was released from damaged acinar cells by cholecystokinin (CCK) induction. rCypA (recombinant CypA) aggravated CCK-induced acinar cell necrosis, promoted nuclear factor (NF)-κB p65 activation, and increased cytokine production. In conclusion, CypA promotes pancreatic damage by upregulating expression of inflammatory cytokines of acinar cells via the NF-κB pathway

  5. Pancreatic acinar cells-derived cyclophilin A promotes pancreatic damage by activating NF-κB pathway in experimental pancreatitis

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ge [Department of Gastroenterology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai (China); Wan, Rong [Department of Gastroenterology, Shanghai First People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Hu, Yanling [Department of Gastroenterology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai (China); Ni, Jianbo [Department of Gastroenterology, Shanghai First People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Yin, Guojian; Xing, Miao [Department of Gastroenterology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai (China); Shen, Jie [Department of Gastroenterology, Shanghai First People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Tang, Maochun [Department of Gastroenterology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai (China); Chen, Congying [Department of Gastroenterology, Shanghai First People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Fan, Yuting; Xiao, Wenqin; Zhao, Yan [Department of Gastroenterology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai (China); Wang, Xingpeng, E-mail: wangxingpeng@hotmail.com [Department of Gastroenterology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai (China); Department of Gastroenterology, Shanghai First People’s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); and others

    2014-01-31

    Highlights: • CypA is upregulated in experimental pancreatitis. • CCK induces expression and release of CypA in acinar cell in vitro. • rCypA aggravates CCK-induced acinar cell death and inflammatory cytokine production. • rCypA activates the NF-κB pathway in acinar cells in vitro. - Abstract: Inflammation triggered by necrotic acinar cells contributes to the pathophysiology of acute pancreatitis (AP), but its precise mechanism remains unclear. Recent studies have shown that Cyclophilin A (CypA) released from necrotic cells is involved in the pathogenesis of several inflammatory diseases. We therefore investigated the role of CypA in experimental AP induced by administration of sodium taurocholate (STC). CypA was markedly upregulated and widely expressed in disrupted acinar cells, infiltrated inflammatory cells, and tubular complexes. In vitro, it was released from damaged acinar cells by cholecystokinin (CCK) induction. rCypA (recombinant CypA) aggravated CCK-induced acinar cell necrosis, promoted nuclear factor (NF)-κB p65 activation, and increased cytokine production. In conclusion, CypA promotes pancreatic damage by upregulating expression of inflammatory cytokines of acinar cells via the NF-κB pathway.

  6. Strategies to improve outcome after islet transplantation using the GLP-1 receptor agonist, extendin-4

    OpenAIRE

    Sharma, Amit

    2007-01-01

    Transplantation of pancreatic islets into the liver via the portal vein has emerged as a treatment option for patients with type I diabetes mellitus. However, loss of functional beta cell mass during isolation and following implantation is a major obstacle in obtaining good long-term results. Exendin-4, a glucagonlike peptide-1 (GLP-1) receptor agonist, improves glucose homeostasis in patients with diabetes. It also has anti-apoptotic and beta cell proliferative properties t...

  7. Mitochondrial oxidative stress contributes differently to rat pancreatic islet cell apoptosis and insulin secretory defects after prolonged culture in a low non-stimulating glucose concentration.

    Science.gov (United States)

    Roma, L P; Pascal, S M; Duprez, J; Jonas, J-C

    2012-08-01

    Pancreatic beta cells chronically exposed to low glucose concentrations show signs of oxidative stress, loss of glucose-stimulated insulin secretion (GSIS) and increased apoptosis. Our aim was to confirm the role of mitochondrial oxidative stress in rat islet cell apoptosis under these culture conditions and to evaluate whether its reduction similarly improves survival and GSIS. Apoptosis, oxidative stress-response gene mRNA expression and glucose-induced stimulation of mitochondrial metabolism, intracellular Ca(2+) concentration and insulin secretion were measured in male Wistar rat islets cultured for 1 week in RPMI medium containing 5-10 mmol/l glucose with or without manganese(III)tetrakis(4-benzoic acid)porphyrin (MnTBAP) or N-acetyl-L-: cysteine (NAC). Oxidative stress was measured in islet cell clusters cultured under similar conditions using cytosolic and mitochondrial redox-sensitive green fluorescent protein (roGFP1/mt-roGFP1). Prolonged culture in 5 vs 10 mmol/l glucose increased mt-roGFP1 (but not roGFP1) oxidation followed by beta cell apoptosis and loss of GSIS resulting from reduced insulin content, mitochondrial metabolism, Ca(2+) influx and Ca(2+)-induced secretion. Tolbutamide-induced, but not high K(+)-induced, Ca(2+) influx was also suppressed. Under these conditions, MnTBAP, but not NAC, triggered parallel ~50-70% reductions in mt-roGFP1 oxidation and beta cell apoptosis, but failed to protect against the loss of GSIS despite significant improvement in glucose-induced and tolbutamide-induced Ca(2+) influx. Mitochondrial oxidative stress contributes differently to rat pancreatic islet cell apoptosis and insulin secretory defects during culture in a low glucose concentration. Thus, targeting beta cell survival may not be sufficient to restore insulin secretion when beta cells suffer from prolonged mitochondrial oxidative stress, e.g. in the context of reduced glucose metabolism.

  8. Serum levels of pancreatic stone protein (PSP/reg1A as an indicator of beta-cell apoptosis suggest an increased apoptosis rate in hepatocyte nuclear factor 1 alpha (HNF1A-MODY carriers from the third decade of life onward

    Directory of Open Access Journals (Sweden)

    Bacon Siobhan

    2012-07-01

    Full Text Available Abstract Background Mutations in the transcription factor hepatocyte nuclear factor-1-alpha (HNF1A result in the commonest type of maturity onset diabetes of the young (MODY. HNF1A-MODY carriers have reduced pancreatic beta cell mass, partially due to an increased rate of apoptosis. To date, it has not been possible to determine when apoptosis is occurring in HNF1A-MODY.We have recently demonstrated that beta cell apoptosis stimulates the expression of the pancreatic stone protein/regenerating (PSP/reg gene in surviving neighbour cells, and that PSP/reg1A protein is subsequently secreted from these cells. The objective of this study was to determine whether serum levels of PSP/reg1A are elevated during disease progression in HNF1A-MODY carriers, and whether it may provide information regarding the onset of beta-cell apoptosis. Methods We analysed serum PSP/reg1A levels and correlated with clinical and biochemical parameters in subjects with HNF1A-MODY, glucokinase (GCK-MODY, and type 1 diabetes mellitus. A control group of normoglycaemic subjects was also analysed. Results PSP/reg1A serum levels were significantly elevated in HNF1A-MODY (n = 37 subjects compared to controls (n = 60 (median = 12.50 ng/ml, IQR = 10.61-17.87 ng/ml versus median = 10.72 ng/ml, IQR = 8.94-12.54 ng/ml, p = 0.0008. PSP/reg1A correlated negatively with insulin levels during OGTT, (rho = −0.40, p = 0.02. Interestingly we noted a significant positive correlation of PSP/reg1A with age of the HNF1A-MODY carriers (rho = 0.40 p = 0.02 with an age of 25 years separating carriers with low and high PSP/reg1A levels. Patients with type 1 diabetes mellitus also had elevated serum levels of PSP/reg1A compared to controls, however this was independent of the duration of diabetes. Conclusion Our data suggest that beta cell apoptosis contributes increasingly to the pathophysiology of HNF1A-MODY in patients 25 years and over

  9. Serum levels of pancreatic stone protein (PSP)/reg1A as an indicator of beta-cell apoptosis suggest an increased apoptosis rate in hepatocyte nuclear factor 1 alpha (HNF1A-MODY) carriers from the third decade of life onward

    LENUS (Irish Health Repository)

    Bacon, Siobhan

    2012-07-18

    AbstractBackgroundMutations in the transcription factor hepatocyte nuclear factor-1-alpha (HNF1A) result in the commonest type of maturity onset diabetes of the young (MODY). HNF1A-MODY carriers have reduced pancreatic beta cell mass, partially due to an increased rate of apoptosis. To date, it has not been possible to determine when apoptosis is occurring in HNF1A-MODY.We have recently demonstrated that beta cell apoptosis stimulates the expression of the pancreatic stone protein\\/regenerating (PSP\\/reg) gene in surviving neighbour cells, and that PSP\\/reg1A protein is subsequently secreted from these cells. The objective of this study was to determine whether serum levels of PSP\\/reg1A are elevated during disease progression in HNF1A-MODY carriers, and whether it may provide information regarding the onset of beta-cell apoptosis.MethodsWe analysed serum PSP\\/reg1A levels and correlated with clinical and biochemical parameters in subjects with HNF1A-MODY, glucokinase (GCK-MODY), and type 1 diabetes mellitus. A control group of normoglycaemic subjects was also analysed.ResultsPSP\\/reg1A serum levels were significantly elevated in HNF1A-MODY (n = 37) subjects compared to controls (n = 60) (median = 12.50 ng\\/ml, IQR = 10.61-17.87 ng\\/ml versus median = 10.72 ng\\/ml, IQR = 8.94-12.54 ng\\/ml, p = 0.0008). PSP\\/reg1A correlated negatively with insulin levels during OGTT, (rho = −0.40, p = 0.02). Interestingly we noted a significant positive correlation of PSP\\/reg1A with age of the HNF1A-MODY carriers (rho = 0.40 p = 0.02) with an age of 25 years separating carriers with low and high PSP\\/reg1A levels. Patients with type 1 diabetes mellitus also had elevated serum levels of PSP\\/reg1A compared to controls, however this was independent of the duration of diabetes.ConclusionOur data suggest that beta cell apoptosis contributes increasingly to the pathophysiology of HNF1A-MODY in patients 25 years and

  10. Interaction of Stellate Cells with Pancreatic Carcinoma Cells

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    Marco Siech

    2010-09-01

    Full Text Available Pancreatic cancer is characterized by its late detection, aggressive growth, intense infiltration into adjacent tissue, early metastasis, resistance to chemo- and radiotherapy and a strong “desmoplastic reaction”. The dense stroma surrounding carcinoma cells is composed of fibroblasts, activated stellate cells (myofibroblast-like cells, various inflammatory cells, proliferating vascular structures, collagens and fibronectin. In particular the cellular components of the stroma produce the tumor microenvironment, which plays a critical role in tumor growth, invasion, spreading, metastasis, angiogenesis, inhibition of anoikis, and chemoresistance. Fibroblasts, myofibroblasts and activated stellate cells produce the extracellular matrix components and are thought to interact actively with tumor cells, thereby promoting cancer progression. In this review, we discuss our current understanding of the role of pancreatic stellate cells (PSC in the desmoplastic response of pancreas cancer and the effects of PSC on tumor progression, metastasis and drug resistance. Finally we present some novel ideas for tumor therapy by interfering with the cancer cell-host interaction.

  11. Exosomes derived from pancreatic cancer cells induce activation and profibrogenic activities in pancreatic stellate cells.

    Science.gov (United States)

    Masamune, Atsushi; Yoshida, Naoki; Hamada, Shin; Takikawa, Tetsuya; Nabeshima, Tatsuhide; Shimosegawa, Tooru

    2018-01-01

    Pancreatic cancer cells (PCCs) interact with pancreatic stellate cells (PSCs), which play a pivotal role in pancreatic fibrogenesis, to develop the cancer-conditioned tumor microenvironment. Exosomes are membrane-enclosed nanovesicles, and have been increasingly recognized as important mediators of cell-to-cell communications. The aim of this study was to clarify the effects of PCC-derived exosomes on cell functions in PSCs. Exosomes were isolated from the conditioned medium of Panc-1 and SUIT-2 PCCs. Human primary PSCs were treated with PCC-derived exosomes. PCC-derived exosomes stimulated the proliferation, migration, activation of ERK and Akt, the mRNA expression of α-smooth muscle actin (ACTA2) and fibrosis-related genes, and procollagen type I C-peptide production in PSCs. Ingenuity pathway analysis of the microarray data identified transforming growth factor β1 and tumor necrosis factor as top upstream regulators. PCCs increased the expression of miR-1246 and miR-1290, abundantly contained in PCC-derived exosomes, in PSCs. Overexpression of miR-1290 induced the expression of ACTA2 and fibrosis-related genes in PSCs. In conclusion, PCC-derived exosomes stimulate activation and profibrogenic activities in PSCs. Exosome-mediated interactions between PSCs and PCCs might play a role in the development of the tumor microenvironment. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Role of the mitochondria in immune-mediated apoptotic death of the human pancreatic β cell line βLox5.

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    Yaíma L Lightfoot

    Full Text Available Mitochondria are indispensable in the life and death of many types of eukaryotic cells. In pancreatic beta cells, mitochondria play an essential role in the secretion of insulin, a hormone that regulates blood glucose levels. Unregulated blood glucose is a hallmark symptom of diabetes. The onset of Type 1 diabetes is preceded by autoimmune-mediated destruction of beta cells. However, the exact role of mitochondria has not been assessed in beta cell death. In this study, we examine the role of mitochondria in both Fas- and proinflammatory cytokine-mediated destruction of the human beta cell line, βLox5. IFNγ primed βLox5 cells for apoptosis by elevating cell surface Fas. Consequently, βLox5 cells were killed by caspase-dependent apoptosis by agonistic activation of Fas, but only after priming with IFNγ. This beta cell line undergoes both apoptotic and necrotic cell death after incubation with the combination of the proinflammatory cytokines IFNγ and TNFα. Additionally, both caspase-dependent and -independent mechanisms that require proper mitochondrial function are involved. Mitochondrial contributions to βLox5 cell death were analyzed using mitochondrial DNA (mtDNA depleted βLox5 cells, or βLox5 ρ(0 cells. βLox5 ρ(0 cells are not sensitive to IFNγ and TNFα killing, indicating a direct role for the mitochondria in cytokine-induced cell death of the parental cell line. However, βLox5 ρ(0 cells are susceptible to Fas killing, implicating caspase-dependent extrinsic apoptotic death is the mechanism by which these human beta cells die after Fas ligation. These data support the hypothesis that immune mediators kill βLox5 cells by both mitochondrial-dependent intrinsic and caspase-dependent extrinsic pathways.

  13. Endothelial Cells Control Pancreatic Cell Fate at Defined Stages through EGFL7 Signaling

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    Der-I Kao

    2015-02-01

    Full Text Available Although endothelial cells have been shown to affect mouse pancreatic development, their precise function in human development remains unclear. Using a coculture system containing human embryonic stem cell (hESC-derived progenitors and endothelial cells, we found that endothelial cells play a stage-dependent role in pancreatic development, in which they maintain pancreatic progenitor (PP self-renewal and impair further differentiation into hormone-expressing cells. The mechanistic studies suggest that the endothelial cells act through the secretion of EGFL7. Consistently, endothelial overexpression of EGFL7 in vivo using a transgenic mouse model resulted in an increase of PP proliferation rate and a decrease of differentiation toward endocrine cells. These studies not only identified the role of EGFL7 as the molecular handle involved in the crosstalk between endothelium and pancreatic epithelium, but also provide a paradigm for using hESC stepwise differentiation to dissect the stage-dependent roles of signals controlling organogenesis.

  14. Partial ablation of adult Drosophila insulin-producing neurons modulates glucose homeostasis and extends life span without insulin resistance.

    Science.gov (United States)

    Haselton, Aaron; Sharmin, Effat; Schrader, Janel; Sah, Megha; Poon, Peter; Fridell, Yih-Woei C

    2010-08-01

    In Drosophila melanogaster (D. melanogaster), neurosecretory insulin-like peptide-producing cells (IPCs), analogous to mammalian pancreatic beta cells are involved in glucose homeostasis. Extending those findings, we have developed in the adult fly an oral glucose tolerance test and demonstrated that IPCs indeed are responsible for executing an acute glucose clearance response. To further develop D. melanogaster as a relevant system for studying age-associated metabolic disorders, we set out to determine the impact of adult-specific partial ablation of IPCs (IPC knockdown) on insulin-like peptide (ILP) action, metabolic outcomes and longevity. Interestingly, while IPC knockdown flies are hyperglycemic and glucose intolerant, these flies remain insulin sensitive as measured by peripheral glucose disposal upon insulin injection and serine phosphorylation of a key insulin-signaling molecule, Akt. Significant increases in stored glycogen and triglyceride levels as well as an elevated level of circulating lipid measured in adult IPC knockdown flies suggest profound modulation in energy metabolism. Additional physiological outcomes measured in those flies include increased resistance to starvation and impaired female fecundity. Finally, increased life span and decreased mortality rates measured in IPC knockdown flies demonstrate that it is possible to modulate ILP action in adult flies to achieve life span extension without insulin resistance. Taken together, we have established and validated an invertebrate genetic system to further investigate insulin action, metabolic homeostasis and regulation of aging regulated by adult IPCs.

  15. Timing of Ca2+ response in pancreatic beta-cells is related to mitochondrial mass

    DEFF Research Database (Denmark)

    Gustavsson, N; Abedi, G; Larsson-Nyrén, G

    2006-01-01

    timing are disturbed in beta-cells from hyperglycemic mice and one of the causes is likely to be an altered mitochondrial metabolism. Mitochondria play a key role in the control of nutrient-induced insulin secretion. Here, we used confocal microscopy with the fluorescent probe MitoTracker Red CMXRos...

  16. Glucose intolerance in a xenotransplantation model

    DEFF Research Database (Denmark)

    Dahl, Kirsten; Buschard, Karsten; Gram, Dorte X.

    2006-01-01

    Xenotransplantation holds the promise of replacing failing human organs with organs of animal origin. Transplantation of pancreatic islets from pigs to humans might restore glucose homeostasis and offer diabetic patients considerable improvement in their quality of life. The alpha-gal epitope...... beta-cell function (p islet xenotransplantation....

  17. Inhibitors of ORAI1 Prevent Cytosolic Calcium-Associated Injury of Human Pancreatic Acinar Cells and Acute Pancreatitis in 3 Mouse Models

    Science.gov (United States)

    Wen, Li; Voronina, Svetlana; Javed, Muhammad A.; Awais, Muhammad; Szatmary, Peter; Latawiec, Diane; Chvanov, Michael; Collier, David; Huang, Wei; Barrett, John; Begg, Malcolm; Stauderman, Ken; Roos, Jack; Grigoryev, Sergey; Ramos, Stephanie; Rogers, Evan; Whitten, Jeff; Velicelebi, Gonul; Dunn, Michael; Tepikin, Alexei V.; Criddle, David N.; Sutton, Robert

    2015-01-01

    Background & Aims Sustained activation of the cytosolic calcium concentration induces injury to pancreatic acinar cells and necrosis. The calcium release–activated calcium modulator ORAI1 is the most abundant Ca2+ entry channel in pancreatic acinar cells; it sustains calcium overload in mice exposed to toxins that induce pancreatitis. We investigated the roles of ORAI1 in pancreatic acinar cell injury and the development of acute pancreatitis in mice. Methods Mouse and human acinar cells, as well as HEK 293 cells transfected to express human ORAI1 with human stromal interaction molecule 1, were hyperstimulated or incubated with human bile acid, thapsigargin, or cyclopiazonic acid to induce calcium entry. GSK-7975A or CM_128 were added to some cells, which were analyzed by confocal and video microscopy and patch clamp recordings. Acute pancreatitis was induced in C57BL/6J mice by ductal injection of taurolithocholic acid 3-sulfate or intravenous' administration of cerulein or ethanol and palmitoleic acid. Some mice then were given GSK-7975A or CM_128, which inhibit ORAI1, at different time points to assess local and systemic effects. Results GSK-7975A and CM_128 each separately inhibited toxin-induced activation of ORAI1 and/or activation of Ca2+ currents after Ca2+ release, in a concentration-dependent manner, in mouse and human pancreatic acinar cells (inhibition >90% of the levels observed in control cells). The ORAI1 inhibitors also prevented activation of the necrotic cell death pathway in mouse and human pancreatic acinar cells. GSK-7975A and CM_128 each inhibited all local and systemic features of acute pancreatitis in all 3 models, in dose- and time-dependent manners. The agents were significantly more effective, in a range of parameters, when given at 1 vs 6 hours after induction of pancreatitis. Conclusions Cytosolic calcium overload, mediated via ORAI1, contributes to the pathogenesis of acute pancreatitis. ORAI1 inhibitors might be developed

  18. SEC23B is required for pancreatic acinar cell function in adult mice

    Science.gov (United States)

    Khoriaty, Rami; Vogel, Nancy; Hoenerhoff, Mark J.; Sans, M. Dolors; Zhu, Guojing; Everett, Lesley; Nelson, Bradley; Durairaj, Haritha; McKnight, Brooke; Zhang, Bin; Ernst, Stephen A.; Ginsburg, David; Williams, John A.

    2017-01-01

    Mice with germline absence of SEC23B die perinatally, exhibiting massive pancreatic degeneration. We generated mice with tamoxifen-inducible, pancreatic acinar cell–specific Sec23b deletion. Inactivation of Sec23b exclusively in the pancreatic acinar cells of adult mice results in decreased overall pancreatic weights from pancreatic cell loss (decreased pancreatic DNA, RNA, and total protein content), as well as degeneration of exocrine cells, decreased zymogen granules, and alterations in the endoplasmic reticulum (ER), ranging from vesicular ER to markedly expanded cisternae with accumulation of moderate-density content or intracisternal granules. Acinar Sec23b deletion results in induction of ER stress and increased apoptosis in the pancreas, potentially explaining the loss of pancreatic cells and decreased pancreatic weight. These findings demonstrate that SEC23B is required for normal function of pancreatic acinar cells in adult mice. PMID:28539403

  19. Histone deacetylases 1 and 3 but not 2 mediate cytokine-induced beta cell apoptosis in INS-1 cells and dispersed primary islets from rats and are differentially regulated in the islets of type 1 diabetic children

    DEFF Research Database (Denmark)

    Lundh, M; Christensen, D P; Damgaard Nielsen, M

    2012-01-01

    onset, HDAC1 was upregulated in beta cells whereas HDAC2 and -3 were downregulated in comparison with five paediatric controls. CONCLUSIONS/INTERPRETATION: These data demonstrate non-redundant functions of islet class I HDACs and suggest that targeting HDAC1 and HDAC3 would provide optimal protection......AIMS/HYPOTHESIS: Histone deacetylases (HDACs) are promising pharmacological targets in cancer and autoimmune diseases. All 11 classical HDACs (HDAC1-11) are found in the pancreatic beta cell, and HDAC inhibitors (HDACi) protect beta cells from inflammatory insults. We investigated which HDACs...... of HDAC1, -2 and -3 rescued INS-1 cells from inflammatory damage. Small hairpin RNAs against HDAC1 and -3, but not HDAC2, reduced pro-inflammatory cytokine-induced beta cell apoptosis in INS-1 and primary rat islets. The protective properties of specific HDAC knock-down correlated with attenuated cytokine...

  20. Adipose Stem Cell Therapy Mitigates Chronic Pancreatitis via Differentiation into Acinar-like Cells in Mice.

    Science.gov (United States)

    Sun, Zhen; Gou, Wenyu; Kim, Do-Sung; Dong, Xiao; Strange, Charlie; Tan, Yu; Adams, David B; Wang, Hongjun

    2017-11-01

    The objective of this study was to assess the capacity of adipose-derived mesenchymal stem cells (ASCs) to mitigate disease progression in an experimental chronic pancreatitis mouse model. Chronic pancreatitis (CP) was induced in C57BL/6 mice by repeated ethanol and cerulein injection, and mice were then infused with 4 × 10 5 or 1 × 10 6 GFP + ASCs. Pancreas morphology, fibrosis, inflammation, and presence of GFP + ASCs in pancreases were assessed 2 weeks after treatment. We found that ASC infusion attenuated pancreatic damage, preserved pancreas morphology, and reduced pancreatic fibrosis and cell death. GFP + ASCs migrated to pancreas and differentiated into amylase + cells. In further confirmation of the plasticity of ASCs, ASCs co-cultured with acinar cells in a Transwell system differentiated into amylase + cells with increased expression of acinar cell-specific genes including amylase and chymoB1. Furthermore, culture of acinar or pancreatic stellate cell lines in ASC-conditioned medium attenuated ethanol and cerulein-induced pro-inflammatory cytokine production in vitro. Our data show that a single intravenous injection of ASCs ameliorated CP progression, likely by directly differentiating into acinar-like cells and by suppressing inflammation, fibrosis, and pancreatic tissue damage. These results suggest that ASC cell therapy has the potential to be a valuable treatment for patients with pancreatitis. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

  1. The nuclear hormone receptor family member NR5A2 controls aspects of multipotent progenitor cell formation and acinar differentiation during pancreatic organogenesis.

    Science.gov (United States)

    Hale, Michael A; Swift, Galvin H; Hoang, Chinh Q; Deering, Tye G; Masui, Toshi; Lee, Youn-Kyoung; Xue, Jumin; MacDonald, Raymond J

    2014-08-01

    The orphan nuclear receptor NR5A2 is necessary for the stem-like properties of the epiblast of the pre-gastrulation embryo and for cellular and physiological homeostasis of endoderm-derived organs postnatally. Using conditional gene inactivation, we show that Nr5a2 also plays crucial regulatory roles during organogenesis. During the formation of the pancreas, Nr5a2 is necessary for the expansion of the nascent pancreatic epithelium, for the subsequent formation of the multipotent progenitor cell (MPC) population that gives rise to pre-acinar cells and bipotent cells with ductal and islet endocrine potential, and for the formation and differentiation of acinar cells. At birth, the NR5A2-deficient pancreas has defects in all three epithelial tissues: a partial loss of endocrine cells, a disrupted ductal tree and a >90% deficit of acini. The acinar defects are due to a combination of fewer MPCs, deficient allocation of those MPCs to pre-acinar fate, disruption of acinar morphogenesis and incomplete acinar cell differentiation. NR5A2 controls these developmental processes directly as well as through regulatory interactions with other pancreatic transcriptional regulators, including PTF1A, MYC, GATA4, FOXA2, RBPJL and MIST1 (BHLHA15). In particular, Nr5a2 and Ptf1a establish mutually reinforcing regulatory interactions and collaborate to control developmentally regulated pancreatic genes by binding to shared transcriptional regulatory regions. At the final stage of acinar cell development, the absence of NR5A2 affects the expression of Ptf1a and its acinar specific partner Rbpjl, so that the few acinar cells that form do not complete differentiation. Nr5a2 controls several temporally distinct stages of pancreatic development that involve regulatory mechanisms relevant to pancreatic oncogenesis and the maintenance of the exocrine phenotype. © 2014. Published by The Company of Biologists Ltd.

  2. Beta cell 5'-shifted isomiRs are candidate regulatory hubs in type 2 diabetes.

    Directory of Open Access Journals (Sweden)

    Jeanette Baran-Gale

    Full Text Available Next-generation deep sequencing of small RNAs has unveiled the complexity of the microRNA (miRNA transcriptome, which is in large part due to the diversity of miRNA sequence variants ("isomiRs". Changes to a miRNA's seed sequence (nucleotides 2-8, including shifted start positions, can redirect targeting to a dramatically different set of RNAs and alter biological function. We performed deep sequencing of small RNA from mouse insulinoma (MIN6 cells (widely used as a surrogate for the study of pancreatic beta cells and developed a bioinformatic analysis pipeline to profile isomiR diversity. Additionally, we applied the pipeline to recently published small RNA-seq data from primary human beta cells and whole islets and compared the miRNA profiles with that of MIN6. We found that: (1 the miRNA expression profile in MIN6 cells is highly correlated with those of primary human beta cells and whole islets; (2 miRNA loci can generate multiple highly expressed isomiRs with different 5'-start positions (5'-isomiRs; (3 isomiRs with shifted start positions (5'-shifted isomiRs are highly expressed, and can be as abundant as their unshifted counterparts (5'-reference miRNAs. Finally, we identified 10 beta cell miRNA families as candidate regulatory hubs in a type 2 diabetes (T2D gene network. The most significant candidate hub was miR-29, which we demonstrated regulates the mRNA levels of several genes critical to beta cell function and implicated in T2D. Three of the candidate miRNA hubs were novel 5'-shifted isomiRs: miR-375+1, miR-375-1 and miR-183-5p+1. We showed by in silico target prediction and in vitro transfection studies that both miR-375+1 and miR-375-1 are likely to target an overlapping, but distinct suite of beta cell genes compared to canonical miR-375. In summary, this study characterizes the isomiR profile in beta cells for the first time, and also highlights the potential functional relevance of 5'-shifted isomiRs to T2D.

  3. High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients

    Science.gov (United States)

    Madsen, Søren Møller; Thorup, Anne Cathrine; Overgaard, Kristian; Jeppesen, Per Bendix

    2015-01-01

    Physical activity improves the regulation of glucose homeostasis in both type 2 diabetes (T2D) patients and healthy individuals, but the effect on pancreatic β cell function is unknown. We investigated glycaemic control, pancreatic function and total fat mass before and after 8 weeks of low volume high intensity interval training (HIIT) on cycle ergometer in T2D patients and matched healthy control individuals. Study design/method: Elderly (56 yrs±2), non-active T2D patients (n = 10) and matched (52 yrs±2) healthy controls (CON) (n = 13) exercised 3 times (10×60 sec. HIIT) a week over an 8 week period on a cycle ergometer. Participants underwent a 2-hour oral glucose tolerance test (OGTT). On a separate day, resting blood pressure measurement was conducted followed by an incremental maximal oxygen uptake (V˙O2max) cycle ergometer test. Finally, a whole body dual X-ray absorptiometry (DXA) was performed. After 8 weeks of training, the same measurements were performed. Results: in the T2D-group, glycaemic control as determined by average fasting venous glucose concentration (p = 0.01), end point 2-hour OGTT (p = 0.04) and glycosylated haemoglobin (p = 0.04) were significantly reduced. Pancreatic homeostasis as determined by homeostatic model assessment of insulin resistance (HOMA-IR) and HOMA β cell function (HOMA-%β) were both significantly ameliorated (p = 0.03 and p = 0.03, respectively). Whole body insulin sensitivity as determined by the disposition index (DI) was significantly increased (p = 0.03). During OGTT, the glucose continuum was significantly reduced at -15 (p = 0.03), 30 (p = 0.03) and 120 min (p = 0.03) and at -10 (p = 0.003) and 0 min (p = 0.003) with an additional improvement (p = 0.03) of its 1st phase (30 min) area under curve (AUC). Significant abdominal fat mass losses were seen in both groups (T2D: p = 0.004 and CON: p = 0.02) corresponding to a percentage change of -17.84%±5.02 and -9.66%±3.07, respectively. Conclusion: these results

  4. High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients.

    Directory of Open Access Journals (Sweden)

    Søren Møller Madsen

    Full Text Available Physical activity improves the regulation of glucose homeostasis in both type 2 diabetes (T2D patients and healthy individuals, but the effect on pancreatic β cell function is unknown. We investigated glycaemic control, pancreatic function and total fat mass before and after 8 weeks of low volume high intensity interval training (HIIT on cycle ergometer in T2D patients and matched healthy control individuals. Study design/method: Elderly (56 yrs±2, non-active T2D patients (n = 10 and matched (52 yrs±2 healthy controls (CON (n = 13 exercised 3 times (10×60 sec. HIIT a week over an 8 week period on a cycle ergometer. Participants underwent a 2-hour oral glucose tolerance test (OGTT. On a separate day, resting blood pressure measurement was conducted followed by an incremental maximal oxygen uptake (VO2max cycle ergometer test. Finally, a whole body dual X-ray absorptiometry (DXA was performed. After 8 weeks of training, the same measurements were performed. Results: in the T2D-group, glycaemic control as determined by average fasting venous glucose concentration (p = 0.01, end point 2-hour OGTT (p = 0.04 and glycosylated haemoglobin (p = 0.04 were significantly reduced. Pancreatic homeostasis as determined by homeostatic model assessment of insulin resistance (HOMA-IR and HOMA β cell function (HOMA-%β were both significantly ameliorated (p = 0.03 and p = 0.03, respectively. Whole body insulin sensitivity as determined by the disposition index (DI was significantly increased (p = 0.03. During OGTT, the glucose continuum was significantly reduced at -15 (p = 0.03, 30 (p = 0.03 and 120 min (p = 0.03 and at -10 (p = 0.003 and 0 min (p = 0.003 with an additional improvement (p = 0.03 of its 1st phase (30 min area under curve (AUC. Significant abdominal fat mass losses were seen in both groups (T2D: p = 0.004 and CON: p = 0.02 corresponding to a percentage change of -17.84%±5.02 and -9.66%±3.07, respectively. Conclusion: these results

  5. Activation of transmembrane bile acid receptor TGR5 stimulates insulin secretion in pancreatic β cells

    International Nuclear Information System (INIS)

    Kumar, Divya P.; Rajagopal, Senthilkumar; Mahavadi, Sunila; Mirshahi, Faridoddin; Grider, John R.; Murthy, Karnam S.; Sanyal, Arun J.

    2012-01-01

    Highlights: ► G protein coupled receptor TGR5 is expressed in mouse and human islets. ► TGR5 is coupled to activation of Gs and Ca 2+ release via cAMP/Epac/PLC-ε pathway. ► Activation of TGR5 by bile salts and selective ligands causes insulin secretion. ► TGR5 could be a potential therapeutic target to treat diabetes. -- Abstract: Bile acids act as signaling molecules and stimulate the G protein coupled receptor, TGR5, in addition to nuclear farnesoid X receptor to regulate lipid, glucose and energy metabolism. Bile acid induced activation of TGR5 in the enteroendocrine cells promotes glucagon like peptide-1 (GLP-1) release, which has insulinotropic effect in the pancreatic β cells. In the present study, we have identified the expression of TGR5 in pancreatic β cell line MIN6 and also in mouse and human pancreatic islets. TGR5 selective ligands, oleanolic acid (OA) and INT-777 selectively activated Gα s and caused an increase in intracellular cAMP and Ca 2+ . OA and INT-777 also increased phosphoinositide (PI) hydrolysis and the increase was blocked by NF449 (a selective Gα s inhibitor) or (U73122) (PI hydrolysis inhibitor). OA, INT-777 and lithocholic acid increased insulin release in MIN6 and human islets and the increase was inhibited by treatment with NF449, (U73122) or BAPTA-AM (chelator of calcium), but not with myristoylated PKI (PKA inhibitor), suggesting that the release is dependent on G s /cAMP/Ca 2+ pathway. 8-pCPT-2′-O-Me-cAMP, a cAMP analog, which activates Epac, but not PKA also stimulated PI hydrolysis. In conclusion, our study demonstrates that the TGR5 expressed in the pancreatic β cells regulates insulin secretion and highlights the importance of ongoing therapeutic strategies targeting TGR5 in the control of glucose homeostasis.

  6. Studies of insulin secretory responses and of arachidonic acid incorporation into phospholipids of stably transfected insulinoma cells that overexpress group VIA phospholipase A2 (iPLA2beta ) indicate a signaling rather than a housekeeping role for iPLA2beta.

    Science.gov (United States)

    Ma, Z; Ramanadham, S; Wohltmann, M; Bohrer, A; Hsu, F F; Turk, J

    2001-04-20

    A cytosolic 84-kDa group VIA phospholipase A(2) (iPLA(2)beta) that does not require Ca(2+) for catalysis has been cloned from several sources, including rat and human pancreatic islet beta-cells and murine P388D1 cells. Many potential iPLA(2)beta functions have been proposed, including a signaling role in beta-cell insulin secretion and a role in generating lysophosphatidylcholine acceptors for arachidonic acid incorporation into P388D1 cell phosphatidylcholine (PC). Proposals for iPLA(2)beta function rest in part on effects of inhibiting iPLA(2)beta activity with a bromoenol lactone (BEL) suicide substrate, but BEL also inhibits phosphatidate phosphohydrolase-1 and a group VIB phospholipase A(2). Manipulation of iPLA(2)beta expression by molecular biologic means is an alternative approach to study iPLA(2)beta functions, and we have used a retroviral construct containing iPLA(2)beta cDNA to prepare two INS-1 insulinoma cell clonal lines that stably overexpress iPLA(2)beta. Compared with parental INS-1 cells or cells transfected with empty vector, both iPLA(2)beta-overexpressing lines exhibit amplified insulin secretory responses to glucose and cAMP-elevating agents, and BEL substantially attenuates stimulated secretion. Electrospray ionization mass spectrometric analyses of arachidonic acid incorporation into INS-1 cell PC indicate that neither overexpression nor inhibition of iPLA(2)beta affects the rate or extent of this process in INS-1 cells. Immunocytofluorescence studies with antibodies directed against iPLA(2)beta indicate that cAMP-elevating agents increase perinuclear fluorescence in INS-1 cells, suggesting that iPLA(2)beta associates with nuclei. These studies are more consistent with a signaling than with a housekeeping role for iPLA(2)beta in insulin-secreting beta-cells.

  7. Spontaneous Pancreatitis Caused by Tissue-Specific Gene Ablation of Hhex in MiceSummary

    Directory of Open Access Journals (Sweden)

    Mark J. Ferreira

    2015-09-01

    Full Text Available Background & Aims: Perturbations in pancreatic ductal bicarbonate secretion cause chronic pancreatitis. The physiologic mechanism of ductal secretion is known, but its transcriptional control is not. We determine the role of the transcription factor hematopoietically expressed homeobox protein (Hhex in ductal secretion and pancreatitis. Methods: We derived mice with pancreas-specific, Cre-mediated Hhex gene ablation to determine the requirement of Hhex in the pancreatic duct in early life and in adult stages. Histologic and immunostaining analyses were used to detect the presence of pathology. Pancreatic primary ductal cells were isolated to discover differentially expressed transcripts upon acute Hhex ablation on a cell autonomous level. Results: Hhex protein was detected throughout the embryonic and adult ductal trees. Ablation of Hhex in pancreatic progenitors resulted in postnatal ductal ectasia associated with acinar-to-ductal metaplasia, a progressive phenotype that ultimately resulted in chronic pancreatitis. Hhex ablation in adult mice, however, did not cause any detectable pathology. Ductal ectasia in young mice did not result from perturbation of expression of Hnf6, Hnf1β, or the primary cilia genes. RNA-seq analysis of Hhex-ablated pancreatic primary ductal cells showed mRNA levels of the G-protein coupled receptor natriuretic peptide receptor 3 (Npr3, implicated in paracrine signaling, up-regulated by 4.70-fold. Conclusions: Although Hhex is dispensable for ductal cell function in the adult, ablation of Hhex in pancreatic progenitors results in pancreatitis. Our data highlight the critical role of Hhex in maintaining ductal homeostasis in early life and support ductal hypersecretion as a novel etiology of pediatric chronic pancreatitis. Keywords: Npr3, Pancreatic Ducts, Primary Cilia

  8. H2O2-Activated Mitochondrial Phospholipase iPLA2 gamma Prevents Lipotoxic Oxidative Stress in Synergy with UCP2, Amplifies Signaling via G-Protein-Coupled Receptor GPR40, and Regulates Insulin Secretion in Pancreatic beta-Cells

    Czech Academy of Sciences Publication Activity Database

    Ježek, Jan; Dlasková, Andrea; Zelenka, Jaroslav; Jabůrek, Martin; Ježek, Petr

    2015-01-01

    Roč. 23, č. 12 (2015), s. 958-972 ISSN 1523-0864 R&D Projects: GA ČR(CZ) GPP303/11/P320; GA ČR(CZ) GA13-02033S; GA ČR(CZ) GA13-06666S; GA ČR GA15-02051S Institutional support: RVO:67985823 Keywords : mitochondrial phospholipase iPLA2 gamma * uncoupling protein UCP2 * G-protein coupled receptor - 40 * glucose-stimulated insulin secretion * pancreatic beta cells Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 7.093, year: 2015

  9. In vitro proliferation of adult human beta-cells.

    Directory of Open Access Journals (Sweden)

    Sabine Rutti

    Full Text Available A decrease in functional beta-cell mass is a key feature of type 2 diabetes. Glucagon-like peptide 1 (GLP-1 analogues induce proliferation of rodent beta-cells. However, the proliferative capacity of human beta-cells and its modulation by GLP-1 analogues remain to be fully investigated. We therefore sought to quantify adult human beta-cell proliferation in vitro and whether this is affected by the GLP-1 analogue liraglutide.Human islets from 7 adult cadaveric organ donors were dispersed into single cells. Beta-cells were purified by FACS. Non-sorted cells and the beta-cell enriched ("beta-cells" population were plated on extracellular matrix from rat (804G and human bladder carcinoma cells (HTB9 or bovine corneal endothelial ECM (BCEC. Cells were maintained in culture+/-liraglutide for 4 days in the presence of BrdU.Rare human beta-cell proliferation could be observed either in the purified beta-cell population (0.051±0.020%; 22 beta-cells proliferating out of 84'283 beta-cells counted or in the non-sorted cell population (0.055±0.011%; 104 proliferating beta-cells out of 232'826 beta-cells counted, independently of the matrix or the culture conditions. Liraglutide increased human beta-cell proliferation on BCEC in the non-sorted cell population (0.082±0.034% proliferating beta-cells vs. 0.017±0.008% in control, p<0.05.These results indicate that adult human beta-cell proliferation can occur in vitro but remains an extremely rare event with these donors and particular culture conditions. Liraglutide increases beta-cell proliferation only in the non-sorted cell population and only on BCEC. However, it cannot be excluded that human beta-cells may proliferate to a greater extent in situ in response to natural stimuli.

  10. Imaging of gene expression in live pancreatic islet cell lines using dual-isotope SPECT.

    Science.gov (United States)

    Tai, Joo Ho; Nguyen, Binh; Wells, R Glenn; Kovacs, Michael S; McGirr, Rebecca; Prato, Frank S; Morgan, Timothy G; Dhanvantari, Savita

    2008-01-01

    We are combining nuclear medicine with molecular biology to establish a sensitive, quantitative, and tomographic method with which to detect gene expression in pancreatic islet cells in vivo. Dual-isotope SPECT can be used to image multiple molecular events simultaneously, and coregistration of SPECT and CT images enables visualization of reporter gene expression in the correct anatomic context. We have engineered pancreatic islet cell lines for imaging with SPECT/CT after transplantation under the kidney capsule. INS-1 832/13 and alphaTC1-6 cells were stably transfected with a herpes simplex virus type 1-thymidine kinase-green fluorescent protein (HSV1-thymidine kinase-GFP) fusion construct (tkgfp). After clonal selection, radiolabel uptake was determined by incubation with 5-(131)I-iodo-1-(2-deoxy-2-fluoro-beta-d-arabinofuranosyl)uracil ((131)I-FIAU) (alphaTC1-6 cells) or (123)I-FIAU (INS-1 832/13 cells). For the first set of in vivo experiments, SPECT was conducted after alphaTC1-6/tkgfp cells had been labeled with either (131)I-FIAU or (111)In-tropolone and transplanted under the left kidney capsule of CD1 mice. Reconstructed SPECT images were coregistered to CT. In a second study using simultaneous acquisition dual-isotope SPECT, INS-1 832/13 clone 9 cells were labeled with (111)In-tropolone before transplantation. Mice were then systemically administered (123)I-FIAU and data for both (131)I and (111)In were acquired simultaneously. alphaTC1-6/tkgfp cells showed a 15-fold greater uptake of (131)I-FIAU, and INS-1/tkgfp cells showed a 12-fold greater uptake of (123)I-FIAU, compared with that of wild-type cells. After transplantation under the kidney capsule, both reporter gene expression and location of cells could be visualized in vivo with dual-isotope SPECT. Immunohistochemistry confirmed the presence of glucagon- and insulin-positive cells at the site of transplantation. Dual-isotope SPECT is a promising method to detect gene expression in and location of

  11. Expression of human cationic trypsinogen (PRSS1) in murine acinar cells promotes pancreatitis and apoptotic cell death

    Science.gov (United States)

    Athwal, T; Huang, W; Mukherjee, R; Latawiec, D; Chvanov, M; Clarke, R; Smith, K; Campbell, F; Merriman, C; Criddle, D; Sutton, R; Neoptolemos, J; Vlatković, N

    2014-01-01

    Hereditary pancreatitis (HP) is an autosomal dominant disease that displays the features of both acute and chronic pancreatitis. Mutations in human cationic trypsinogen (PRSS1) are associated with HP and have provided some insight into the pathogenesis of pancreatitis, but mechanisms responsible for the initiation of pancreatitis have not been elucidated and the role of apoptosis and necrosis has been much debated. However, it has been generally accepted that trypsinogen, prematurely activated within the pancreatic acinar cell, has a major role in the initiation process. Functional studies of HP have been limited by the absence of an experimental system that authentically mimics disease development. We therefore developed a novel transgenic murine model system using wild-type (WT) human PRSS1 or two HP-associated mutants (R122H and N29I) to determine whether expression of human cationic trypsinogen in murine acinar cells promotes pancreatitis. The rat elastase promoter was used to target transgene expression to pancreatic acinar cells in three transgenic strains that were generated: Tg(Ela-PRSS1)NV, Tg(Ela-PRSS1*R122H)NV and Tg(Ela-PRSS1*N29I)NV. Mice were analysed histologically, immunohistochemically and biochemically. We found that transgene expression is restricted to pancreatic acinar cells and transgenic PRSS1 proteins are targeted to the pancreatic secretory pathway. Animals from all transgenic strains developed pancreatitis characterised by acinar cell vacuolisation, inflammatory infiltrates and fibrosis. Transgenic animals also developed more severe pancreatitis upon treatment with low-dose cerulein than controls, displaying significantly higher scores for oedema, inflammation and overall histopathology. Expression of PRSS1, WT or mutant, in acinar cells increased apoptosis in pancreatic tissues and isolated acinar cells. Moreover, studies of isolated acinar cells demonstrated that transgene expression promotes apoptosis rather than necrosis. We therefore

  12. Inhibition of Cell Survival by Curcumin Is Associated with Downregulation of Cell Division Cycle 20 (Cdc20) in Pancreatic Cancer Cells.

    Science.gov (United States)

    Zhang, Yu; Xue, Ying-Bo; Li, Hang; Qiu, Dong; Wang, Zhi-Wei; Tan, Shi-Sheng

    2017-02-04

    Pancreatic cancer is one of the most aggressive human tumors in the United States. Curcumin, a polyphenol derived from the Curcuma longa plant, has been reported to exert its antitumor activity in pancreatic cancer. However, the molecular mechanisms of curcumin-mediated tumor suppressive function have not been fully elucidated. In the current study, we explore whether curcumin exhibits its anti-cancer function through inhibition of oncoprotein cell division cycle 20 (Cdc20) in pancreatic cancer cells. We found that curcumin inhibited cell growth, enhanced apoptosis, induced cell cycle arrest and retarded cell invasion in pancreatic cancer cells. Moreover, we observed that curcumin significantly inhibited the expression of Cdc20 in pancreatic cancer cells. Furthermore, our results demonstrated that overexpression of Cdc20 enhanced cell proliferation and invasion, and abrogated the cytotoxic effects induced by curcumin in pancreatic cancer cells. Consistently, downregulation of Cdc20 promoted curcumin-mediated anti-tumor activity. Therefore, our findings indicated that inhibition of Cdc20 by curcumin could be useful for the treatment of pancreatic cancer patients.

  13. Association of arsenobetaine with beta-cell function assessed by homeostasis model assessment (HOMA) in nondiabetic Koreans: data from the fourth Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2009.

    Science.gov (United States)

    Baek, Kiook; Lee, Namhoon; Chung, Insung

    2017-01-01

    Arsenic is known as an endocrine disruptor that people are exposed to through various sources such as drinking water and indigestion of marine products. Although some epidemiological and animal studies have reported a correlation between arsenic exposure and diabetes development, there are limited studies regarding the toxic effects of organic arsenic including arsenobetaine on the human body. Here, we analyzed the association between urine arsenobetaine and the homeostasis model assessment of β-cell function (HOMA-β), which is an index for predicting diabetes development and reflecting the function of pancreatic β-cells. In the fourth Korea National Health and Nutrition Examination Survey (KNHANES), health and nutrition surveys and screening tests were performed. Of the total survey population, people with confirmed values for urine total arsenic and arsenobetaine were included, and known diabetic patients were excluded. A total 369 participants were finally included in the study. We collected surveys on health, height, body weight, body mass index, blood mercury level, fasting glucose level, and serum insulin level and calculated HOMA index. Owing to sexual discrepancy, we performed sexually stratified analysis. Urine total arsenic and total arsenic minus arsenobetaine was not associated with HOMA-IR and HOMA-β in univariate analysis or in sexually stratified analysis. However, urine arsenobetaine showed a statistically significant relationship with HOMA-β in univariate analysis, and only male participants showed a significant correlation in sexually stratified analysis. In the analysis adjusted for age, BMI, smoking, alcohol drinking, physical activity and blood mercury, the HOMA-β value in the group below the 25th percentile of arsenobetaine was significantly higher than the group between 50 and 75th percentile, while no difference was shown for HOMA-IR. In sexually stratified analysis, The value of HOMA-β was significantly higher in male participants

  14. Using CRISPR/Cas9 to Knock out Amylase in Acinar Cells Decreases Pancreatitis-Induced Autophagy

    Directory of Open Access Journals (Sweden)

    Kohei Yasunaga

    2018-01-01

    Full Text Available Pancreatic cancer is a malignant neoplasm that originates from acinar cells. Acinar cells get reprogrammed to become duct cells, resulting in pancreatic cancer. Pancreatitis is an acinar cell inflammation, leading to “impaired autophagy flux”. Pancreatitis promotes acinar-to-ductal transdifferentiation. Expression of amylase gets eliminated during the progression of pancreatic cancer. Amylase is considered as an acinar cell marker; however, its function in cells is not known. Thus, we investigated whether amylase affects the acinar cell autophagy and whether it plays any role in development of pancreatitis. Here, we knocked out ATG12 in a pancreatic cancer cells and acinar cells using CRISPR/Cas9. Autophagy inhibition led to an increase in the expression of duct cell markers and a simultaneous decrease in that of acinar cell markers. It also caused an increase in cell viability and changes in mitochondrial morphology. Next, we knocked out amylase in acinar cells. Amylase deficiency decreased autophagy induced by pancreatitis. Our results suggest that amylase controls pancreatitis-induced autophagy. We found that eliminating amylase expression contributes to pancreatic cancer etiology by decreasing autophagy. Furthermore, our results indicate that amylase plays a role in selective pancreatitis-induced autophagy of pancreatic enzyme vesicles.

  15. Pancreatic fat and β-cell function in overweight/obese children with nonalcoholic fatty liver disease.

    Science.gov (United States)

    Pacifico, Lucia; Di Martino, Michele; Anania, Caterina; Andreoli, Gian Marco; Bezzi, Mario; Catalano, Carlo; Chiesa, Claudio

    2015-04-21

    To analyze the associations of pancreatic fat with other fat depots and β-cell function in pediatric nonalcoholic fatty liver disease (NAFLD). We examined 158 overweight/obese children and adolescents, 80 with NAFLD [hepatic fat fraction (HFF) ≥ 5%] and 78 without fatty liver. Visceral adipose tissue (VAT), pancreatic fat fraction (PFF) and HFF were determined by magnetic resonance imaging. Estimates of insulin sensitivity were calculated using the homeostasis model assessment of insulin resistance (HOMA-IR), defined by fasting insulin and fasting glucose and whole-body insulin sensitivity index (WBISI), based on mean values of insulin and glucose obtained from oral glucose tolerance test and the corresponding fasting values. Patients were considered to have prediabetes if they had either: (1) impaired fasting glucose, defined as a fasting glucose level ≥ 100 mg/dL to Children with prediabetes had higher PFF and HFF than those without. PFF and HFF were significantly associated with prediabetes after adjustment for clinical variables. When all fat depots where included in the same model, only HFF remained significantly associated with prediabetes (OR = 3.38; 95%CI: 1.10-10.4; P = 0.034). In overweight/obese children with NAFLD, pancreatic fat is increased compared with those without liver involvement. However, only liver fat is independently related to prediabetes.

  16. Gene expression patterns in pancreatic tumors, cells and tissues.

    Directory of Open Access Journals (Sweden)

    Anson W Lowe

    2007-03-01

    Full Text Available Cancers of the pancreas originate from both the endocrine and exocrine elements of the organ, and represent a major cause of cancer-related death. This study provides a comprehensive assessment of gene expression for pancreatic tumors, the normal pancreas, and nonneoplastic pancreatic disease.DNA microarrays were used to assess the gene expression for surgically derived pancreatic adenocarcinomas, islet cell tumors, and mesenchymal tumors. The addition of normal pancreata, isolated islets, isolated pancreatic ducts, and pancreatic adenocarcinoma cell lines enhanced subsequent analysis by increasing the diversity in gene expression profiles obtained. Exocrine, endocrine, and mesenchymal tumors displayed unique gene expression profiles. Similarities in gene expression support the pancreatic duct as the origin of adenocarcinomas. In addition, genes highly expressed in other cancers and associated with specific signal transduction pathways were also found in pancreatic tumors.The scope of the present work was enhanced by the inclusion of publicly available datasets that encompass a wide spectrum of human tissues and enabled the identification of candidate genes that may serve diagnostic and therapeutic goals.

  17. TLR9 ligation in pancreatic stellate cells promotes tumorigenesis.

    Science.gov (United States)

    Zambirinis, Constantinos P; Levie, Elliot; Nguy, Susanna; Avanzi, Antonina; Barilla, Rocky; Xu, Yijie; Seifert, Lena; Daley, Donnele; Greco, Stephanie H; Deutsch, Michael; Jonnadula, Saikiran; Torres-Hernandez, Alejandro; Tippens, Daniel; Pushalkar, Smruti; Eisenthal, Andrew; Saxena, Deepak; Ahn, Jiyoung; Hajdu, Cristina; Engle, Dannielle D; Tuveson, David; Miller, George

    2015-11-16

    Modulation of Toll-like receptor (TLR) signaling can have protective or protumorigenic effects on oncogenesis depending on the cancer subtype and on specific inflammatory elements within the tumor milieu. We found that TLR9 is widely expressed early during the course of pancreatic transformation and that TLR9 ligands are ubiquitous within the tumor microenvironment. TLR9 ligation markedly accelerates oncogenesis, whereas TLR9 deletion is protective. We show that TLR9 activation has distinct effects on the epithelial, inflammatory, and fibrogenic cellular subsets in pancreatic carcinoma and plays a central role in cross talk between these compartments. Specifically, TLR9 activation can induce proinflammatory signaling in transformed epithelial cells, but does not elicit oncogene expression or cancer cell proliferation. Conversely, TLR9 ligation induces pancreatic stellate cells (PSCs) to become fibrogenic and secrete chemokines that promote epithelial cell proliferation. TLR9-activated PSCs mediate their protumorigenic effects on the epithelial compartment via CCL11. Additionally, TLR9 has immune-suppressive effects in the tumor microenvironment (TME) via induction of regulatory T cell recruitment and myeloid-derived suppressor cell proliferation. Collectively, our work shows that TLR9 has protumorigenic effects in pancreatic carcinoma which are distinct from its influence in extrapancreatic malignancies and from the mechanistic effects of other TLRs on pancreatic oncogenesis. © 2015 Zambirinis et al.

  18. **-Postprandial pancreatic ["1"1C]methionine uptake after pancreaticoduodenectomy mirrors basal beta cell function and insulin release

    International Nuclear Information System (INIS)

    Steiner, Emanuel; Kazianka, Lukas; Breuer, Robert; Miholic, Johannes; Hacker, Marcus; Wadsak, Wolfgang; Mitterhauser, Markus; Stimpfl, Thomas; Reiter, Birgit; Karanikas, Georgios

    2017-01-01

    [S-methyl-"1"1C]-L-methionine (["1"1C]MET) uptake in the pancreas might be a central indicator of beta cell function. Since gastric emptying was recently shown to influence glycemic control in subjects after pancreaticoduodenectomy (PD, the surgical treatment of neoplasms of the pancreas head), we looked for imaginable relationships between gastric emptying, pre- and postprandial insulin concentrations, and ["1"1C]MET uptake. Nineteen tumor-free survivors after PD (age mean ± SD: 61 ± 8.7 yrs.; 10 male, 9 female) and 10 healthy controls (age: 27 ± 8.7 yrs.; 7 male, 3 female) were given a mixed test meal. One gram of paracetamol was ingested with the meal to evaluate the speed of gastric emptying. Insulin, glucose, and paracetamol plasma concentrations were measured before and over 180 minutes after ingestion. Beta cell function was calculated from fasting glucose and insulin plasma concentrations. Simultaneously, 800 MBq of ["1"1C]MET were administered and the activity (maximum tissue standardized uptake values [SUVmax]) over the pancreas was measured at 15, 30, and 60 minutes after injection. Total integrated SUVmax (area under the curve [AUC]) and incremental SUVmax were calculated. The uptake of ["1"1C]MET in the pancreas was significantly higher (p < 0.0001) in controls compared to the PD group. Gastric emptying was significantly slower in controls compared to pancreatectomy subjects (p < 0.0001). Paracetamol AUC_3_0 correlated with the SUVmax increment between 15 and 30 minutes (R"2 = 0.27, p = 0.0263), suggesting a relationship between gastric emptying and the uptake of ["1"1C]MET. Total integrated SUVmax correlated with insulin AUC_6_0 (R"2 = 0.66,p < 0.0001) in patients after PD. Multivariate regression analysis revealed insulin AUC_6_0 and beta cell function, calculated from the fasting insulin to glucose ratio, as independent predictors of "1"1C-methionine uptake, i.e. total integrated SUVmax, in patients after PD (R"2 = 0.78, p < 0.0001). Postprandial

  19. **-Postprandial pancreatic [{sup 11}C]methionine uptake after pancreaticoduodenectomy mirrors basal beta cell function and insulin release

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, Emanuel; Kazianka, Lukas; Breuer, Robert; Miholic, Johannes [Medical University of Vienna, Department of Surgery, Vienna (Austria); Hacker, Marcus; Wadsak, Wolfgang; Mitterhauser, Markus [Medical University of Vienna, Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Vienna (Austria); Stimpfl, Thomas; Reiter, Birgit [Medical University of Vienna, Clinical Institute of Laboratory Medicine, Forensic Toxicology, Vienna (Austria); Karanikas, Georgios [Medical University of Vienna, Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Divisional Head PET-PET/CT (Nuclear Medicine), Vienna (Austria)

    2017-03-15

    [S-methyl-{sup 11}C]-L-methionine ([{sup 11}C]MET) uptake in the pancreas might be a central indicator of beta cell function. Since gastric emptying was recently shown to influence glycemic control in subjects after pancreaticoduodenectomy (PD, the surgical treatment of neoplasms of the pancreas head), we looked for imaginable relationships between gastric emptying, pre- and postprandial insulin concentrations, and [{sup 11}C]MET uptake. Nineteen tumor-free survivors after PD (age mean ± SD: 61 ± 8.7 yrs.; 10 male, 9 female) and 10 healthy controls (age: 27 ± 8.7 yrs.; 7 male, 3 female) were given a mixed test meal. One gram of paracetamol was ingested with the meal to evaluate the speed of gastric emptying. Insulin, glucose, and paracetamol plasma concentrations were measured before and over 180 minutes after ingestion. Beta cell function was calculated from fasting glucose and insulin plasma concentrations. Simultaneously, 800 MBq of [{sup 11}C]MET were administered and the activity (maximum tissue standardized uptake values [SUVmax]) over the pancreas was measured at 15, 30, and 60 minutes after injection. Total integrated SUVmax (area under the curve [AUC]) and incremental SUVmax were calculated. The uptake of [{sup 11}C]MET in the pancreas was significantly higher (p < 0.0001) in controls compared to the PD group. Gastric emptying was significantly slower in controls compared to pancreatectomy subjects (p < 0.0001). Paracetamol AUC{sub 30} correlated with the SUVmax increment between 15 and 30 minutes (R{sup 2} = 0.27, p = 0.0263), suggesting a relationship between gastric emptying and the uptake of [{sup 11}C]MET. Total integrated SUVmax correlated with insulin AUC{sub 60} (R{sup 2} = 0.66,p < 0.0001) in patients after PD. Multivariate regression analysis revealed insulin AUC{sub 60} and beta cell function, calculated from the fasting insulin to glucose ratio, as independent predictors of {sup 11}C-methionine uptake, i.e. total integrated SUVmax, in

  20. Multilayer network representation of membrane potential and cytosolic calcium concentration dynamics in beta cells

    International Nuclear Information System (INIS)

    Gosak, Marko; Dolenšek, Jurij; Markovič, Rene; Slak Rupnik, Marjan; Marhl, Marko; Stožer, Andraž

    2015-01-01

    Highlights: • Physiological processes within and among pancreatic beta cells are very complex. • We analyze the simultaneous recordings of membrane potential and calcium dynamics. • We represent the interaction patterns among beta cells as a multilayer network. • The nature of the intracellular dynamics is found to rely on the network structure. - Abstract: Modern theory of networks has been recognized as a very successful methodological concept for the description and analysis of complex systems. However, some complex systems are more complex than others. For instance, several real-life systems are constituted by interdependent subsystems and their elements are subjected to different types of interactions that can also change with time. Recently, the multilayer network formalism has been proposed as a general theoretical framework for the description and analysis of such multi-dimensional complex systems and is acquiring more and more prominence in terms of a new research direction. In the present study, we use this methodology for the description of functional connectivity patterns and signal propagation between pancreatic beta cells in an islet of Langerhans at the levels of membrane potential (MP) and cytosolic calcium concentration ([Ca"2"+]_c) dynamics to study the extent of overlap in the two networks and to clarify whether time lags between the two signals in individual cells are in any way dependent on the role these cells play in the functional networks. The two corresponding network layers are constructed on the basis of signal directions and pairwise correlations, whereas the interlayer connections represent the time lag between both measured signals. Our results confirm our previous finding that both MP and [Ca"2"+]_c change spread across an islet in the form of a depolarization and a [Ca"2"+]_c wave, respectively. Both types of waves follow nearly the same path and the networks in both layers have a similar but not entirely the same structure

  1. [Effects of ezrin silencing on pancreatic cancer cell line Panc-1].

    Science.gov (United States)

    Meng, Yun-xiao; Yu, Shuang-ni; Lu, Zhao-hui; Chen, Jie

    2012-12-01

    To explore the effects of ezrin silencing on pancreatic cancer cell line Panc-1. Pancreatic cancer cell line Panc-1 was transfected with ezrin silencing plasmid. The proliferation and the cell cycle status were determined by CCK-8 assay and flow cytometry analysis, respectively. Cellular membrane protrusions/microvilli formation were visualized by scanning election microscopy. Colony formation assay was used to determine the cell anchor-independent growth ability in vitro. Trans-filter migration and invasion assays were performed with 8 µm pore inserts in a 24-well BioCoat chamber with/without Matrigel. Ezrin silencing decreased cellular protrusions/microvilli formation, anchorage-independent growth, cell migration and invasion, but had no effects on cell proliferation in vitro and cell cycle, in pancreatic cancer cell line Panc-1. Ezrin expression affects the cellular protrusions/microvilli formation, anchorage-independent growth, cell migration and invasion in pancreatic cancer cell line Panc-1.

  2. Coronin-1A links cytoskeleton dynamics to TCR alpha beta-induced cell signaling.

    Directory of Open Access Journals (Sweden)

    Bénédicte Mugnier

    Full Text Available Actin polymerization plays a critical role in activated T lymphocytes both in regulating T cell receptor (TCR-induced immunological synapse (IS formation and signaling. Using gene targeting, we demonstrate that the hematopoietic specific, actin- and Arp2/3 complex-binding protein coronin-1A contributes to both processes. Coronin-1A-deficient mice specifically showed alterations in terminal development and the survival of alpha beta T cells, together with defects in cell activation and cytokine production following TCR triggering. The mutant T cells further displayed excessive accumulation yet reduced dynamics of F-actin and the WASP-Arp2/3 machinery at the IS, correlating with extended cell-cell contact. Cell signaling was also affected with the basal activation of the stress kinases sAPK/JNK1/2; and deficits in TCR-induced Ca2+ influx and phosphorylation and degradation of the inhibitor of NF-kappaB (I kappa B. Coronin-1A therefore links cytoskeleton plasticity with the functioning of discrete TCR signaling components. This function may be required to adjust TCR responses to selecting ligands accounting in part for the homeostasis defect that impacts alpha beta T cells in coronin-1A deficient mice, with the exclusion of other lympho/hematopoietic lineages.

  3. Pancreatic alpha-cell dysfunction contributes to the disruption of glucose homeostasis and compensatory insulin hypersecretion in glucocorticoid-treated rats.

    Directory of Open Access Journals (Sweden)

    Alex Rafacho

    Full Text Available Glucocorticoid (GC-based therapies can cause insulin resistance (IR, glucose intolerance, hyperglycemia and, occasionally, overt diabetes. Understanding the mechanisms behind these metabolic disorders could improve the management of glucose homeostasis in patients undergoing GC treatment. For this purpose, adult rats were treated with a daily injection of dexamethasone (1 mg/kg b.w., i.p. (DEX or saline as a control for 5 consecutive days. The DEX rats developed IR, augmented glycemia, hyperinsulinemia and hyperglucagonemia. Treatment of the DEX rats with a glucagon receptor antagonist normalized their blood glucose level. The characteristic inhibitory effect of glucose on glucagon secretion was impaired in the islets of the DEX rats, while no direct effects were found on α-cells in islets that were incubated with DEX in vitro. A higher proportion of docked secretory granules was found in the DEX α-cells as well as a trend towards increased α-cell mass. Additionally, insulin secretion in the presence of glucagon was augmented in the islets of the DEX rats, which was most likely due to their higher glucagon receptor content. We also found that the enzyme 11βHSD-1, which participates in GC metabolism, contributed to the insulin hypersecretion in the DEX rats under basal glucose conditions. Altogether, we showed that GC treatment induces hyperglucagonemia, which contributes to an imbalance in glucose homeostasis and compensatory β-cell hypersecretion. This hyperglucagonemia may result from altered α-cell function and, likely, α-cell mass. Additionally, blockage of the glucagon receptor seems to be effective in preventing the elevation in blood glucose levels induced by GC administration.

  4. File list: Unc.Pan.50.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Pan.50.AllAg.Pancreatic_cancer_cells mm9 Unclassified Pancreas Pancreatic cancer... cells http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Pan.50.AllAg.Pancreatic_cancer_cells.bed ...

  5. Profile of MMP and TIMP Expression in Human Pancreatic Stellate Cells: Regulation by IL-1α and TGFβ and Implications for Migration of Pancreatic Cancer Cells

    Directory of Open Access Journals (Sweden)

    Vegard Tjomsland

    2016-07-01

    Full Text Available Pancreatic ductal adenocarcinoma is characterized by a prominent fibroinflammatory stroma with both tumor-promoting and tumor-suppressive functions. The pancreatic stellate cell (PSC is the major cellular stromal component and the main producer of extracellular matrix proteins, including collagens, which are degraded by metalloproteinases (MMPs. PSCs interact with cancer cells through various factors, including transforming growth factor (TGFβ and interleukin (IL-1α. The role of TGFβ in the dual nature of tumor stroma, i.e., protumorigenic or tumor suppressive, is not clear. We aimed to investigate the roles of TGFβ and IL-1α in the regulation of MMP profiles in PSCs and the subsequent effects on cancer cell migration. Human PSCs isolated from surgically resected specimens were cultured in the presence of pancreatic cancer cell lines, as well as IL-1α or TGFβ. MMP production and activities in PSCs were quantified by gene array transcripts, mRNA measurements, fluorescence resonance energy transfer–based activity assay, and zymography. PSC-conditioned media and pancreatic cancer cells were included in a collagen matrix cell migration model. We found that production of IL-1α by pancreatic cancer cells induced alterations in MMP and tissue inhibitors of matrix metalloproteinase (TIMP profiles and activities in PSCs, upregulated expression and activation of MMP1 and MMP3, and enhanced migration of pancreatic cancer cells in the collagen matrix model. TGFβ counteracted the effects of IL-1α on PSCs, reestablished PSC MMP and TIMP profiles and activities, and inhibited migration of cancer cells. This suggests that tumor TGFβ has a role as a suppressor of stromal promotion of tumor progression through alterations in PSC MMP profiles with subsequent inhibition of pancreatic cancer cell migration.

  6. Effects of Ghrelin miRNA on Inflammation and Calcium Pathway in Pancreatic Acinar Cells of Acute Pancreatitis.

    Science.gov (United States)

    Tang, Xiping; Tang, Guodu; Liang, Zhihai; Qin, Mengbin; Fang, Chunyun; Zhang, Luyi

    The study investigated the effects of endogenous targeted inhibition of ghrelin gene on inflammation and calcium pathway in an in vitro pancreatic acinar cell model of acute pancreatitis. Lentiviral expression vector against ghrelin gene was constructed and transfected into AR42J cells. The mRNA and protein expression of each gene were detected by reverse transcription polymerase chain reaction, Western blotting, or enzyme-linked immunosorbent assay. The concentration of intracellular calcium ([Ca]i) was determined by calcium fluorescence mark probe combined with laser scanning confocal microscopy. Compared with the control group, cerulein could upregulate mRNA and protein expression of inflammatory factors, calcium pathway, ghrelin, and [Ca]i. mRNA and protein expression of inflammatory factors increased significantly in cells transfected with ghrelin miRNA compared with the other groups. Intracellular calcium and expression of some calcium pathway proteins decreased significantly in cells transfected with ghrelin miRNA compared with the other groups. Targeted inhibition of ghrelin gene in pancreatic acinar cells of acute pancreatitis can upregulate the expression of the intracellular inflammatory factors and alleviate the intracellular calcium overload.

  7. File list: His.Pan.20.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  8. File list: His.Pan.10.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.10.AllAg.Pancreatic_cancer_cells mm9 Histone Pancreas Pancreatic cancer cel...ls http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Pan.10.AllAg.Pancreatic_cancer_cells.bed ...

  9. File list: Pol.Pan.50.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Pan.50.AllAg.Pancreatic_cancer_cells mm9 RNA polymerase Pancreas Pancreatic cancer... cells http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Pan.50.AllAg.Pancreatic_cancer_cells.bed ...

  10. File list: His.Pan.50.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Pan.50.AllAg.Pancreatic_cancer_cells mm9 Histone Pancreas Pancreatic cancer cel...ls http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Pan.50.AllAg.Pancreatic_cancer_cells.bed ...

  11. Generation of polyhormonal and multipotent pancreatic progenitor lineages from human pluripotent stem cells.

    Science.gov (United States)

    Korytnikov, Roman; Nostro, Maria Cristina

    2016-05-15

    Generation of pancreatic β-cells from human pluripotent stem cells (hPSCs) has enormous importance in type 1 diabetes (T1D), as it is fundamental to a treatment strategy based on cellular therapeutics. Being able to generate β-cells, as well as other mature pancreatic cells, from human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) will also enable the development of platforms that can be used for disease modeling and drug testing for a variety of pancreas-associated diseases, including cystic fibrosis. For this to occur, it is crucial to develop differentiation strategies that are robust and reproducible across cell lines and laboratories. In this article we describe two serum-free differentiation protocols designed to generate specific pancreatic lineages from hPSCs. Our approach employs a variety of cytokines and small molecules to mimic developmental pathways active during pancreatic organogenesis and allows for the in vitro generation of distinct pancreatic populations. The first protocol is designed to give rise to polyhormonal cells that have the potential to differentiate into glucagon-producing cells. The second protocol is geared to generate multipotent pancreatic progenitor cells, which harbor the potential to generate all pancreatic lineages including: monohormonal endocrine cells, acinar, and ductal cells. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. File list: DNS.Pan.20.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Pan.20.AllAg.Pancreatic_cancer_cells mm9 DNase-seq Pancreas Pancreatic cancer c...ells http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Pan.20.AllAg.Pancreatic_cancer_cells.bed ...

  13. Pancreatic adenocarcinoma upregulated factor (PAUF) confers resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNA receptor-mediated signaling

    Energy Technology Data Exchange (ETDEWEB)

    Kaowinn, Sirichat; Cho, Il-Rae; Moon, Jeong; Jun, Seung Won; Kim, Chang Seok [BK21+, Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-736 (Korea, Republic of); Kang, Ho Young [Department of Microbiology, Pusan National University, Busan 609-736 (Korea, Republic of); Kim, Manbok [Department of Medical Science, Dankook University College of Medicine, Cheonan 330-714 (Korea, Republic of); Koh, Sang Seok [Department of Biological Sciences, Dong-A University, Busan 604-714 (Korea, Republic of); Chung, Young-Hwa, E-mail: younghc@pusan.ac.kr [BK21+, Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-736 (Korea, Republic of)

    2015-04-03

    Pancreatic adenocarcinoma upregulated factor (PAUF), a novel oncogene, plays a crucial role in the development of pancreatic cancer, including its metastasis and proliferation. Therefore, PAUF-expressing pancreatic cancer cells could be important targets for oncolytic virus-mediated treatment. Panc-1 cells expressing PAUF (Panc-PAUF) showed relative resistance to parvovirus H-1 infection compared with Panc-1 cells expressing an empty vector (Panc-Vec). Of interest, expression of type I IFN-α receptor (IFNAR) was higher in Panc-PAUF cells than in Panc-Vec cells. Increased expression of IFNAR in turn increased the activation of Stat1 and Tyk2 in Panc-PAUF cells compared with that in Panc-Vec cells. Suppression of Tyk2 and Stat1, which are important downstream molecules for IFN-α signaling, sensitized pancreatic cancer cells to parvovirus H-1-mediated apoptosis. Further, constitutive suppression of PAUF sensitized Bxpc3 pancreatic cancer cells to parvovirus H-1 infection. Taken together, these results suggested that PAUF conferred resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNAR-mediated signaling. - Highlights: • PAUF confers resistance against oncolytic parvovirus H-1 infection. • PAUF enhances the expression of IFNAR in Panc-1 cells. • Increased activation of Tyk2 or Stat1 by PAUF provides resistance to parvovirus H-1-mediated apoptosis. • Constitutive inhibition of PAUF enhances parvovirus H-1-mediated oncolysis of Bxpc3 pancreatic cancer cells.

  14. Pancreatic adenocarcinoma upregulated factor (PAUF) confers resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNA receptor-mediated signaling

    International Nuclear Information System (INIS)

    Kaowinn, Sirichat; Cho, Il-Rae; Moon, Jeong; Jun, Seung Won; Kim, Chang Seok; Kang, Ho Young; Kim, Manbok; Koh, Sang Seok; Chung, Young-Hwa

    2015-01-01

    Pancreatic adenocarcinoma upregulated factor (PAUF), a novel oncogene, plays a crucial role in the development of pancreatic cancer, including its metastasis and proliferation. Therefore, PAUF-expressing pancreatic cancer cells could be important targets for oncolytic virus-mediated treatment. Panc-1 cells expressing PAUF (Panc-PAUF) showed relative resistance to parvovirus H-1 infection compared with Panc-1 cells expressing an empty vector (Panc-Vec). Of interest, expression of type I IFN-α receptor (IFNAR) was higher in Panc-PAUF cells than in Panc-Vec cells. Increased expression of IFNAR in turn increased the activation of Stat1 and Tyk2 in Panc-PAUF cells compared with that in Panc-Vec cells. Suppression of Tyk2 and Stat1, which are important downstream molecules for IFN-α signaling, sensitized pancreatic cancer cells to parvovirus H-1-mediated apoptosis. Further, constitutive suppression of PAUF sensitized Bxpc3 pancreatic cancer cells to parvovirus H-1 infection. Taken together, these results suggested that PAUF conferred resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNAR-mediated signaling. - Highlights: • PAUF confers resistance against oncolytic parvovirus H-1 infection. • PAUF enhances the expression of IFNAR in Panc-1 cells. • Increased activation of Tyk2 or Stat1 by PAUF provides resistance to parvovirus H-1-mediated apoptosis. • Constitutive inhibition of PAUF enhances parvovirus H-1-mediated oncolysis of Bxpc3 pancreatic cancer cells

  15. Expansion and conversion of human pancreatic ductal cells into insulin-secreting endocrine cells.

    Science.gov (United States)

    Lee, Jonghyeob; Sugiyama, Takuya; Liu, Yinghua; Wang, Jing; Gu, Xueying; Lei, Ji; Markmann, James F; Miyazaki, Satsuki; Miyazaki, Jun-Ichi; Szot, Gregory L; Bottino, Rita; Kim, Seung K

    2013-11-19

    Pancreatic islet β-cell insufficiency underlies pathogenesis of diabetes mellitus; thus, functional β-cell replacement from renewable sources is the focus of intensive worldwide effort. However, in vitro production of progeny that secrete insulin in response to physiological cues from primary human cells has proven elusive. Here we describe fractionation, expansion and conversion of primary adult human pancreatic ductal cells into progeny resembling native β-cells. FACS-sorted adult human ductal cells clonally expanded as spheres in culture, while retaining ductal characteristics. Expression of the cardinal islet developmental regulators Neurog3, MafA, Pdx1 and Pax6 converted exocrine duct cells into endocrine progeny with hallmark β-cell properties, including the ability to synthesize, process and store insulin, and secrete it in response to glucose or other depolarizing stimuli. These studies provide evidence that genetic reprogramming of expandable human pancreatic cells with defined factors may serve as a general strategy for islet replacement in diabetes. DOI: http://dx.doi.org/10.7554/eLife.00940.001.

  16. miR-132 and miR-212 are increased in pancreatic cancer and target the retinoblastoma tumor suppressor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-Kook [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States); Henry, Jon C. [Department of Surgery, Ohio State University, Columbus, OH 43210 (United States); Jiang, Jinmai [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States); Esau, Christine [Regulus Therapeutics, Carlsbad, CA (United States); Gusev, Yuriy [Lombardi Cancer Center, Georgetown University, Washington, DC (United States); Lerner, Megan R. [Veterans Affairs Medical Center, Oklahoma City, OK (United States); Postier, Russell G. [Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Brackett, Daniel J. [Veterans Affairs Medical Center, Oklahoma City, OK (United States); Schmittgen, Thomas D., E-mail: Schmittgen.2@osu.edu [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States)

    2011-03-25

    Research highlights: {yields} The expression of miR-132 and miR-212 are significantly increased in pancreatic cancer. {yields} miR-132 and miR-212 target the tumor suppressor pRb, resulting in enhanced proliferation. {yields} miR-132 and miR-212 expression is increased by a {beta}2 adrenergic receptor agonist, suggesting a novel mechanism for pancreatic cancer progression. -- Abstract: Numerous microRNAs (miRNAs) are reported as differentially expressed in cancer, however the consequence of miRNA deregulation in cancer is unknown for many miRNAs. We report that two miRNAs located on chromosome 17p13, miR-132 and miR-212, are over-expressed in pancreatic adenocarcinoma (PDAC) tissues. Both miRNAs are predicted to target the retinoblastoma tumor suppressor, Rb1. Validation of this interaction was confirmed by luciferase reporter assay and western blot in a pancreatic cancer cell line transfected with pre-miR-212 and pre-miR-132 oligos. Cell proliferation was enhanced in Panc-1 cells transfected with pre-miR-132/-212 oligos. Conversely, antisense oligos to miR-132/-212 reduced cell proliferation and caused a G{sub 2}/M cell cycle arrest. The mRNA of a number of E2F transcriptional targets were increased in cells over expressing miR-132/-212. Exposing Panc-1 cells to the {beta}2 adrenergic receptor agonist, terbutaline, increased the miR-132 and miR-212 expression by 2- to 4-fold. We report that over-expression of miR-132 and miR-212 result in reduced pRb protein in pancreatic cancer cells and that the increase in cell proliferation from over-expression of these miRNAs is likely due to increased expression of several E2F target genes. The {beta}2 adrenergic pathway may play an important role in this novel mechanism.

  17. Inhibition of pancreatic tumoral cells by snake venom disintegrins.

    Science.gov (United States)

    Lucena, Sara; Castro, Roberto; Lundin, Courtney; Hofstetter, Amanda; Alaniz, Amber; Suntravat, Montamas; Sánchez, Elda Eliza

    2015-01-01

    Pancreatic cancer often has a poor prognosis, even when diagnosed early. Pancreatic cancer typically spreads rapidly and is rarely detected in its early stages, which is a major reason it is a leading cause of cancer death. Signs and symptoms may not appear until pancreatic cancer is quite advanced, and complete surgical removal is not possible. Furthermore, pancreatic cancer responds poorly to most chemotherapeutic agents. The importance of integrins in several cell types that affect tumor progression has made them an appealing target for cancer therapy. Some of the proteins found in the snake venom present a great potential as anti-tumor agents. In this study, we summarize the activity of two integrins antagonist, recombinant disintegrins mojastin 1 and viridistatin 2, on human pancreatic carcinoma cell line (BXPC-3). Both recombinant disintegrins inhibited some essential aspects of the metastasis process such as proliferation, adhesion, migration, and survival through apoptosis, making these proteins prominent candidates for the development of drugs for the treatment of pancreatic cancer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Pancreatic Islet Cell Transplantation: A new era in transplantation

    OpenAIRE

    Warnock, Garth L.; Rajotte, Ray V.

    1992-01-01

    Transplantation of insulin-producing tissue offers a physiologic approach to restoration of glycemic control. Whereas transplantation of vascularized pancreatic grafts has recently achieved encouraging results, pancreatic islet cell transplantation holds the promise of low morbidity and reduced requirements for agressive immunosuppression for recipients. Islet cell transplantation was recently demonstrated to induce euglycemia with insulin independence.

  19. Role of Melatonin, Galanin, and RFamide Neuropeptides QRFP26 and QRFP43 in the Neuroendocrine Control of Pancreatic β-Cell Function

    Directory of Open Access Journals (Sweden)

    Iacopo Gesmundo

    2017-07-01

    Full Text Available Glucose homeostasis is finely regulated by a number of hormones and peptides released mainly from the brain, gastrointestinal tract, and muscle, regulating pancreatic secretion through cellular receptors and their signal transduction cascades. The endocrine function of the pancreas is controlled by islets within the exocrine pancreatic tissue that release hormones like insulin, glucagon, somatostatin, pancreatic polypeptide, and ghrelin. Moreover, both exocrine and endocrine pancreatic functions are regulated by a variety of hormonal and neural mechanisms, such as ghrelin, glucagon-like peptide, glucose-dependent insulinotropic polypeptide, or the inhibitory peptide somatostatin. In this review, we describe the role of neurohormones that have been less characterized compared to others, on the regulation of insulin secretion. In particular, we will focus on melatonin, galanin, and RFamide neuropeptides QRFP26 and QRFP43, which display either insulinotropic or insulinostatic effects. In fact, in addition to other hormones, amino acids, cytokines, and a variety of proteins, brain-derived hormones are now considered as key regulators of glucose homeostasis, representing potential therapeutic targets for the treatment of diabetes and obesity.

  20. File list: ALL.Pan.05.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Pan.05.AllAg.Pancreatic_cancer_cells mm9 All antigens Pancreas Pancreatic cancer... cells SRX174586,SRX174585,SRX174587 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Pan.05.AllAg.Pancreatic_cancer_cells.bed ...

  1. File list: Oth.Pan.20.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Pan.20.AllAg.Pancreatic_cancer_cells mm9 TFs and others Pancreas Pancreatic cancer... cells SRX174585,SRX174586 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Pan.20.AllAg.Pancreatic_cancer_cells.bed ...

  2. File list: Oth.Pan.05.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Pan.05.AllAg.Pancreatic_cancer_cells mm9 TFs and others Pancreas Pancreatic cancer... cells SRX174586,SRX174585 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Pan.05.AllAg.Pancreatic_cancer_cells.bed ...

  3. File list: ALL.Pan.50.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Pan.50.AllAg.Pancreatic_cancer_cells mm9 All antigens Pancreas Pancreatic cancer... cells SRX174585,SRX174586,SRX174587 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Pan.50.AllAg.Pancreatic_cancer_cells.bed ...

  4. The Cytotoxic Role of Intermittent High Glucose on Apoptosis and Cell Viability in Pancreatic Beta Cells

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2014-01-01

    Full Text Available Objectives. Glucose fluctuations are both strong predictor of diabetic complications and crucial factor for beta cell damages. Here we investigated the effect of intermittent high glucose (IHG on both cell apoptosis and proliferation activity in INS-1 cells and the potential mechanisms. Methods. Cells were treated with normal glucose (5.5 mmol/L, constant high glucose (CHG (25 mmol/L, and IHG (rotation per 24 h in 11.1 or 25 mmol/L for 7 days. Reactive oxygen species (ROS, xanthine oxidase (XOD level, apoptosis, cell viability, cell cycle, and expression of cyclinD1, p21, p27, and Skp2 were determined. Results. We found that IHG induced more significant apoptosis than CHG and normal glucose; intracellular ROS and XOD levels were more markedly increased in cells exposed to IHG. Cells treated with IHG showed significant decreased cell viability and increased cell proportion in G0/G1 phase. Cell cycle related proteins such as cyclinD1 and Skp2 were decreased significantly, but expressions of p27 and p21 were increased markedly. Conclusions. This study suggested that IHG plays a more toxic effect including both apoptosis-inducing and antiproliferative effects on INS-1 cells. Excessive activation of cellular stress and regulation of cyclins might be potential mechanism of impairment in INS-1 cells induced by IHG.

  5. Chinese herb derived-Rocaglamide A is a potent inhibitor of pancreatic cancer cells.

    Science.gov (United States)

    Wang, Baochun; Li, Yixiong; Tan, Fengbo; Xiao, Zhanxiang

    2016-01-01

    Pancreatic cancer ranks No.1 in mortality rate worldwide. This study aims to identify the novel anti-pancreatic cancer drugs. Human pancreatic carcinoma cell lines were purchased from ATCC. CPE-based screening assay was used to examine the cell viability. Patient derived tumor xenografts in SCID mice was established. The Caspase-3 and 7 activities were measured using the Caspase Glo 3/7 Assay kit. Soft agar colony formation assay was used to evaluate the colony formation. Wound healing assay was employed to determine the cell migration. We screened a Chinese herbal product library and found three "hits" that kill cancer cells at nanomolar to micromolar concentrations. One of these compounds, rocaglamide, was found to be potent inhibitors of a wide spectrum of pancreatic cancer cell lines. Furthermore, Rocaglamide reduced the tumor size in a patient-derived pancreatic cancer xenograft mouse model without noticeable toxicity in vivo. Rocaglamide also inhibits pancreatic cancer cell migration and invasion. In conclusion, these data support that Rocaglamide may be a promising anti-pancreatic cancer drug.

  6. Regulation of CCK-induced ERK1/2 activation by PKC epsilon in rat pancreatic acinar cells

    Directory of Open Access Journals (Sweden)

    Chenwei Li

    2017-11-01

    Full Text Available The extracellular signal-regulated kinase ERK1/2 is activated in pancreatic acinar cells by cholecystokinin (CCK and other secretagogues with this activation mediated primarily by protein kinase C (PKC. To identify the responsible PKC isoform, we utilized chemical inhibitors, cell permeant inhibitory peptides and overexpression of individual PKC dominant negative variants by means of adenoviral vectors. While the broad-spectrum PKC inhibitor GF109203X strongly inhibited ERK1/2 activation induced by 100 pM CCK, Go6976 which inhibits the classical PKC isoforms (alpha, beta and gamma, as well as Rottlerin, a specific PKC delta inhibitor, had no inhibitory effect. To test the role of PKC epsilon, we used specific cell permeant peptide inhibitors which block PKC interaction with their intracellular receptors or RACKs. Only PP93 (PKC epsilon peptide inhibitor inhibited CCK-induced ERK1/2 activation, while PP95, PP101 and PP98, which are PKC alpha, delta and zeta peptide inhibitors respectively, had no effect. We also utilized adenovirus to express dominant negative PKC isoforms in pancreatic acini. Only PKC epsilon dominant negative inhibited CCK-induced ERK1/2 activation. Dominant negative PKC epsilon expression similarly blocked the effect of carbachol and bombesin to activate ERK1/2. Immunoprecipitation results demonstrated that CCK can induce an interaction of c-Raf-1 and PKC epsilon, but not that of other isoforms of Raf or PKC. We conclude that PKC epsilon is the isoform of PKC primarily involved with CCK-induced ERK1/2 activation in pancreatic acinar cells.

  7. Ku70 inhibits gemcitabine-induced DNA damage and pancreatic cancer cell apoptosis

    International Nuclear Information System (INIS)

    Ma, Jiali; Hui, Pingping; Meng, Wenying; Wang, Na; Xiang, Shihao

    2017-01-01

    The current study focused on the role of Ku70, a DNA-dependent protein kinase (DNA-PK) complex protein, in pancreatic cancer cell resistance to gemcitabine. In both established cell lines (Mia-PaCa-2 and PANC-1) and primary human pancreatic cancer cells, shRNA/siRNA-mediated knockdown of Ku70 significantly sensitized gemcitabine-induced cell death and proliferation inhibition. Meanwhile, gemcitabine-induced DNA damage and subsequent pancreatic cancer cell apoptosis were also potentiated with Ku70 knockdown. On the other hand, exogenous overexpression of Ku70 in Mia-PaCa-2 cells suppressed gemcitabine-induced DNA damage and subsequent cell apoptosis. In a severe combined immune deficient (SCID) mice Mia-PaCa-2 xenograft model, gemcitabine-induced anti-tumor activity was remarkably pontificated when combined with Ku70 shRNA knockdown in the xenografts. The results of this preclinical study imply that Ku70 might be a primary resistance factor of gemcitabine, and Ku70 silence could significantly chemo-sensitize gemcitabine in pancreatic cancer cells. - Highlights: • Ku70 knockdown sensitizes gemcitabine-induced killing of pancreatic cancer cells. • Ku70 knockdown facilitates gemcitabine-induced DNA damage and cell apoptosis. • Ku70 overexpression deceases gemcitabine's sensitivity in pancreatic cancer cells. • Ku70 knockdown sensitizes gemcitabine-induced anti-tumor activity in vivo.

  8. Establishment of three-dimensional cultures of human pancreatic duct epithelial cells

    International Nuclear Information System (INIS)

    Gutierrez-Barrera, Angelica M.; Menter, David G.; Abbruzzese, James L.; Reddy, Shrikanth A.G.

    2007-01-01

    Three-dimensional (3D) cultures of epithelial cells offer singular advantages for studies of morphogenesis or the role of cancer genes in oncogenesis. In this study, as part of establishing a 3D culture system of pancreatic duct epithelial cells, we compared human pancreatic duct epithelial cells (HPDE-E6E7) with pancreatic cancer cell lines. Our results show, that in contrast to cancer cells, HPDE-E6E7 organized into spheroids with what appeared to be apical and basal membranes and a luminal space. Immunostaining experiments indicated that protein kinase Akt was phosphorylated (Ser473) and CTMP, a negative Akt regulator, was expressed in both HPDE-E6E7 and cancer cells. However, a nuclear pool of CTMP was detectable in HPDE-E6E7 cells that showed a dynamic concentrated expression pattern, a feature that further distinguished HPDE-E637 cells from cancer cells. Collectively, these data suggest that 3D cultures of HPDE-E6E7 cells are useful for investigating signaling and morphological abnormalities in pancreatic cancer cells

  9. Long-Term Culture of Self-renewing Pancreatic Progenitors Derived from Human Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Jamie Trott

    2017-06-01

    Full Text Available Pluripotent stem cells have been proposed as an unlimited source of pancreatic β cells for studying and treating diabetes. However, the long, multi-step differentiation protocols used to generate functional β cells inevitably exhibit considerable variability, particularly when applied to pluripotent cells from diverse genetic backgrounds. We have developed culture conditions that support long-term self-renewal of human multipotent pancreatic progenitors, which are developmentally more proximal to the specialized cells of the adult pancreas. These cultured pancreatic progenitor (cPP cells express key pancreatic transcription factors, including PDX1 and SOX9, and exhibit transcriptomes closely related to their in vivo counterparts. Upon exposure to differentiation cues, cPP cells give rise to pancreatic endocrine, acinar, and ductal lineages, indicating multilineage potency. Furthermore, cPP cells generate insulin+ β-like cells in vitro and in vivo, suggesting that they offer a convenient alternative to pluripotent cells as a source of adult cell types for modeling pancreatic development and diabetes.

  10. Reconstructing human pancreatic differentiation by mapping specific cell populations during development

    DEFF Research Database (Denmark)

    Ramond, Cyrille; Glaser, Nicolas; Berthault, Claire

    2017-01-01

    . Endocrine maturation progresses by up-regulating SUSD2 and lowering ECAD levels. Finally, in vitro differentiation of pancreatic endocrine cells derived from human pluripotent stem cells mimics key in vivo events. Our work paves the way to extend our understanding of the origin of mature human pancreatic......Information remains scarce on human development compared to animal models. Here, we reconstructed human fetal pancreatic differentiation using cell surface markers. We demonstrate that at 7weeks of development, the glycoprotein 2 (GP2) marks a multipotent cell population that will differentiate...... cell types and how such lineage decisions are regulated....

  11. Effect of cyclophilin A on gene expression in human pancreatic cancer cells.

    Science.gov (United States)

    Li, Min; Wang, Hao; Li, Fei; Fisher, William E; Chen, Changyi; Yao, Qizhi

    2005-11-01

    We previously found that cyclophilin A (CypA) is overexpressed in human pancreatic cancer cells and stimulates cell proliferation through CD147. In this study, we further investigated the effect of CypA on gene expression of several key molecules that are involved in pancreatic cancer cell proliferation. Human pancreatic cancer cell lines (Panc-1, MIA PaCa-2, and BxPC-3) and human pancreatic ductal epithelial (HPDE) cells were used. The messenger RNA (mRNA) levels of CypA, CypB, CD147, neuropilins (NRPs), vascular endothelial growth factor (VEGF), and VEGF receptors upon the treatment of exogenous recombinant human CypA were determined by real-time reverse-transcription polymerase chain reaction. Exogenous human recombinant CypA reduced the mRNA levels of NRP-1 and VEGF, but not endogenous CypA, CypB, and CD147, in Panc-1, MIA PaCa-2, and BxPC-3 cells. In contrast, HPDE cells showed a decrease of endogenous CypA and CD147 mRNA, but not detectable changes of CypB, NRPs, and VEGF mRNA levels upon exogenous CypA treatment. These data show that exogenous CypA downregulates NRP-1 and VEGF expression in pancreatic cancer cells. This effect is different in normal HPDE cells. Thus, soluble CypA may affect cell growth of pancreatic cancer.

  12. Pim-3 contributes to radioresistance through regulation of the cell cycle and DNA damage repair in pancreatic cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang-Yuan; Wang, Zhen [Cancer Research Institute, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Li, Bei [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Zhang, Ying-Jian, E-mail: yjzhang111@aliyun.com [Department of Nuclear Medicine, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Li, Ying-Yi, E-mail: liyingyi@fudan.edu.cn [Cancer Research Institute, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China)

    2016-04-22

    Resistance of cancer cells to chemoradiotherapy is a major clinical problem in pancreatic cancer treatment. Therefore, understanding the molecular basis of cellular resistance and identifying novel targets are essential for improving treatment efficacy for pancreatic cancer patients. Previous studies have demonstrated a significant role for Pim-3 in pancreatic cancer survival against gemcitabine-induced genotoxic stress. Here, we observed that radiation treatment enhanced Pim-3 expression in human pancreatic cancer cells in vitro. Stable overexpression of Pim-3 in pancreatic cancer cells significantly protected cells against radiation treatment by attenuating G2/M phase cell cycle arrest and DNA damage response. Silencing of Pim-3 expression significantly elevated the phosphorylation of histone variant H2AX, a marker of DNA double strand breaks, and decreased the activation of ataxia-telangiectasia-mutated (ATM) kinase, along with its downstream targets, eventually enhancing the radiosensitivity of human pancreatic cancer cells in vitro and in vivo. Hence, we demonstrated a novel function for Pim-3 in human pancreatic cancer cell survival against radiation. Targeting Pim-3 may be a promising way to improve treatment efficacy in combination with radiotherapy in human pancreatic cancer. - Highlights: • This is first study to demonstrate that Pim-3 is endogenously induced by ionizing radiation in pancreatic cancer cells, and Pim-3 overexpression enhanced radioresistance of pancreatic cancer cells both in vitro and in vivo. • This is first study to provide evidence that radioresistance induced by Pim-3 is mainly attributed to Pim-3 induces activation of ATM, which subsequently activates checkpoint 1, leading to amplification of DNA repair through cell cycle arrest and DNA repair pathways. • This is first study to indicate that targeting Pim-3 may be a promising strategy to provide better treatment efficacy in combination with radiotherapy in human pancreatic

  13. Pim-3 contributes to radioresistance through regulation of the cell cycle and DNA damage repair in pancreatic cancer cells

    International Nuclear Information System (INIS)

    Chen, Xiang-Yuan; Wang, Zhen; Li, Bei; Zhang, Ying-Jian; Li, Ying-Yi

    2016-01-01

    Resistance of cancer cells to chemoradiotherapy is a major clinical problem in pancreatic cancer treatment. Therefore, understanding the molecular basis of cellular resistance and identifying novel targets are essential for improving treatment efficacy for pancreatic cancer patients. Previous studies have demonstrated a significant role for Pim-3 in pancreatic cancer survival against gemcitabine-induced genotoxic stress. Here, we observed that radiation treatment enhanced Pim-3 expression in human pancreatic cancer cells in vitro. Stable overexpression of Pim-3 in pancreatic cancer cells significantly protected cells against radiation treatment by attenuating G2/M phase cell cycle arrest and DNA damage response. Silencing of Pim-3 expression significantly elevated the phosphorylation of histone variant H2AX, a marker of DNA double strand breaks, and decreased the activation of ataxia-telangiectasia-mutated (ATM) kinase, along with its downstream targets, eventually enhancing the radiosensitivity of human pancreatic cancer cells in vitro and in vivo. Hence, we demonstrated a novel function for Pim-3 in human pancreatic cancer cell survival against radiation. Targeting Pim-3 may be a promising way to improve treatment efficacy in combination with radiotherapy in human pancreatic cancer. - Highlights: • This is first study to demonstrate that Pim-3 is endogenously induced by ionizing radiation in pancreatic cancer cells, and Pim-3 overexpression enhanced radioresistance of pancreatic cancer cells both in vitro and in vivo. • This is first study to provide evidence that radioresistance induced by Pim-3 is mainly attributed to Pim-3 induces activation of ATM, which subsequently activates checkpoint 1, leading to amplification of DNA repair through cell cycle arrest and DNA repair pathways. • This is first study to indicate that targeting Pim-3 may be a promising strategy to provide better treatment efficacy in combination with radiotherapy in human pancreatic

  14. Generation of Transplantable Beta Cells for Patient-Specific Cell Therapy

    Directory of Open Access Journals (Sweden)

    Xiaojie Wang

    2012-01-01

    Full Text Available Islet cell transplantation offers a potential cure for type 1 diabetes, but it is challenged by insufficient donor tissue and side effects of current immunosuppressive drugs. Therefore, alternative sources of insulin-producing cells and isletfriendly immunosuppression are required to increase the efficiency and safety of this procedure. Beta cells can be transdifferentiated from precursors or another heterologous (non-beta-cell source. Recent advances in beta cell regeneration from somatic cells such as fibroblasts could circumvent the usage of immunosuppressive drugs. Therefore, generation of patient-specific beta cells provides the potential of an evolutionary treatment for patients with diabetes.

  15. Microcapsules with intrinsic barium radiopacity for immunoprotection and X-ray/CT imaging of pancreatic islet cells.

    Science.gov (United States)

    Arifin, Dian R; Manek, Sameer; Call, Emma; Arepally, Aravind; Bulte, Jeff W M

    2012-06-01

    Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444 ± 21 μm) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-l-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mm barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3-4 weeks in vitro, with secreted human C-peptide levels of 0.2-160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. The anti-oxidative transcription factor Nuclear factor E2 related factor-2 (Nrf2) counteracts TGF-β1 mediated growth inhibition of pancreatic ductal epithelial cells -Nrf2 as determinant of pro-tumorigenic functions of TGF-β1

    International Nuclear Information System (INIS)

    Genrich, Geeske; Kruppa, Marcus; Lenk, Lennart; Helm, Ole; Broich, Anna; Freitag-Wolf, Sandra; Röcken, Christoph; Sipos, Bence; Schäfer, Heiner; Sebens, Susanne

    2016-01-01

    Nuclear factor E2 related factor-2 (Nrf2) is an oxidative stress inducible transcription factor being essential in regulating cell homeostasis. Thus, acute induction of Nrf2 in epithelial cells exposed to inflammation confers protection from oxidative cell damage and mutagenesis supporting an anti-tumorigenic role for Nrf2. However, pancreatic ductal adenocarcinoma (PDAC) is characterized by persistent Nrf2 activity conferring therapy resistance which points to a pro-tumorigenic role of Nrf2. A similar dichotomous role in tumorigenesis is described for the Transforming Growth Factor-beta 1 (TGF-β1). The present study therefore aimed at elucidating whether the switch of Nrf2 function towards a tumor promoting one relates to the modulation of TGF-β1 induced cell responses and whether this might occur early in PDAC development. In situ analysis comprised immunohistochemical stainings of activated (phosphorylated) Nrf2 and Ki67 in pancreatic tissues containing normal ducts and pancreatic intraepithelial neoplasia (PanINs). In vitro, Nrf2 levels in benign (H6c7-pBp), premalignant (H6c7-kras) and malignant (Colo357) pancreatic ductal epithelial cells were modulated by Nrf2 specific siRNA or Nrf2 overexpression. Then, the effect of Nrf2 alone and in combination with TGF-β1 on cell growth and survival was investigated by cell counting, Ki67 staining and apoptosis assays. The underlying cell signaling was investigated by western blotting. Statistical analysis was performed by Shapiro-Wilk test for normal distribution. Parametric data were analyzed by one-way ANOVA, while non-parametric data were analyzed by Kruskal-Wallis one-way ANOVA on ranks. Significantly elevated expression of activated Nrf2 and Ki67 could be detected in PanINs but not in normal pancreatic ductal epithelium. While the effect of Nrf2 on basal cell growth of H6c7-pBp, H6c7-kras and Colo357 cells was minor, it clearly attenuated the growth inhibiting effects of TGF-β1 in all cell lines. This enhanced

  17. Nanotopography Promotes Pancreatic Differentiation of Human Embryonic Stem Cells and Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Kim, Jong Hyun; Kim, Hyung Woo; Cha, Kyoung Je; Han, Jiyou; Jang, Yu Jin; Kim, Dong Sung; Kim, Jong-Hoon

    2016-03-22

    Although previous studies suggest that nanotopographical features influence properties and behaviors of stem cells, only a few studies have attempted to derive clinically useful somatic cells from human pluripotent stem cells using nanopatterned surfaces. In the present study, we report that polystyrene nanopore-patterned surfaces significantly promote the pancreatic differentiation of human embryonic and induced pluripotent stem cells. We compared different diameters of nanopores and showed that 200 nm nanopore-patterned surfaces highly upregulated the expression of PDX1, a critical transcription factor for pancreatic development, leading to an approximately 3-fold increase in the percentage of differentiating PDX1(+) pancreatic progenitors compared with control flat surfaces. Furthermore, in the presence of biochemical factors, 200 nm nanopore-patterned surfaces profoundly enhanced the derivation of pancreatic endocrine cells producing insulin, glucagon, or somatostatin. We also demonstrate that nanopore-patterned surface-induced upregulation of PDX1 is associated with downregulation of TAZ, suggesting the potential role of TAZ in nanopore-patterned surface-mediated mechanotransduction. Our study suggests that appropriate cytokine treatments combined with nanotopographical stimulation could be a powerful tool for deriving a high purity of desired cells from human pluripotent stem cells.

  18. Dendritic cells fused with different pancreatic carcinoma cells induce different T-cell responses

    Directory of Open Access Journals (Sweden)

    Andoh Y

    2013-01-01

    Full Text Available Yoshiaki Andoh,1,2 Naohiko Makino,2 Mitsunori Yamakawa11Department of Pathological Diagnostics, 2Department of Gastroenterology, Yamagata University School of Medicine, Yamagata, JapanBackground: It is unclear whether there are any differences in the induction of cytotoxic T lymphocytes (CTL and CD4+CD25high regulatory T-cells (Tregs among dendritic cells (DCs fused with different pancreatic carcinomas. The aim of this study was to compare the ability to induce cytotoxicity by human DCs fused with different human pancreatic carcinoma cell lines and to elucidate the causes of variable cytotoxicity among cell lines.Methods: Monocyte-derived DCs, which were generated from peripheral blood mononuclear cells (PBMCs, were fused with carcinoma cells such as Panc-1, KP-1NL, QGP-1, and KP-3L. The induction of CTL and Tregs, and cytokine profile of PBMCs stimulated by fused DCs were evaluated.Results: The cytotoxicity against tumor targets induced by PBMCs cocultured with DCs fused with QGP-1 (DC/QGP-1 was very low, even though PBMCs cocultured with DCs fused with other cell lines induced significant cytotoxicity against the respective tumor target. The factors causing this low cytotoxicity were subsequently investigated. DC/QGP-1 induced a significant expansion of Tregs in cocultured PBMCs compared with DC/KP-3L. The level of interleukin-10 secreted in the supernatants of PBMCs cocultured with DC/QGP-1 was increased significantly compared with that in DC/KP-3L. Downregulation of major histocompatibility complex class I expression and increased secretion of vascular endothelial growth factor were observed with QGP-1, as well as in the other cell lines.Conclusion: The present study demonstrated that the cytotoxicity induced by DCs fused with pancreatic cancer cell lines was different between each cell line, and that the reduced cytotoxicity of DC/QGP-1 might be related to the increased secretion of interleukin-10 and the extensive induction of Tregs

  19. IRF8 Transcription-Factor-Dependent Classical Dendritic Cells Are Essential for Intestinal T Cell Homeostasis

    DEFF Research Database (Denmark)

    Luda, Katarzyna M.; Joeris, Thorsten; Persson, Emma K.

    2016-01-01

    The role of dendritic cells (DCs) in intestinal immune homeostasis remains incompletely defined. Here we show that mice lacking IRF8 transcription-factor-dependent DCs had reduced numbers of T cells in the small intestine (SI), but not large intestine (LI), including an almost complete absence...... dependent DCs in the maintenance of intestinal T cell homeostasis....

  20. Culture of hESC-derived pancreatic progenitors in alginate-based scaffolds.

    Science.gov (United States)

    Formo, Kjetil; Cho, Candy H-H; Vallier, Ludovic; Strand, Berit L

    2015-12-01

    The effect of alginate-based scaffolds with added basement membrane proteins on the in vitro development of hESC-derived pancreatic progenitors was investigated. Cell clusters were encapsulated in scaffolds containing the basement membrane proteins collagen IV, laminin, fibronectin, or extracellular matrix-derived peptides, and maintained in culture for up to 46 days. The cells remained viable throughout the experiment with no signs of central necrosis. Whereas nonencapsulated cells aggregated into larger clusters, some of which showed signs of morphological changes and tissue organization, the alginate matrix stabilized the cluster size and displayed more homogeneous cell morphologies, allowing culture for long periods of time. For all conditions tested, a stable or declining expression of insulin and PDX1 and an increase in glucagon and somatostatin over time indicated a progressive reduction in beta cell-related gene expression. Alginate scaffolds can provide a chemically defined, xeno-free and easily scalable alternative for culture of pancreatic progenitors. Although no increase in insulin and PDX1 gene expression after alginate-immobilized cell culture was seen in this study, further optimization of the matrix physicochemical and biological properties and of the medium composition may still be a relevant strategy to promote the stabilization or maturation of stem cell-derived beta cells. © 2015 Wiley Periodicals, Inc.

  1. The physiology of a local renin-angiotensin system in the pancreas.

    Science.gov (United States)

    Leung, Po Sing

    2007-04-01

    The systemic renin-angiotensin system (RAS) plays an important role in regulating blood pressure, electrolyte and fluid homeostasis. However, local RASs also exist in diverse tissues and organs, where they play a multitude of autocrine, paracrine and intracrine physiological roles. The existence of a local RAS is now recognized in pancreatic acinar, islet, duct, endothelial and stellate cells, the expression of which is modulated in response to physiological and pathophysiological stimuli such as hypoxia, pancreatitis, islet transplantation, hyperglycaemia, and diabetes mellitus. This pancreatic RAS has been proposed to have important endocrine and exocrine roles in the pancreas, regulating local blood flow, duct cell sodium bicarbonate secretion, acinar cell digestive enzyme secretion, islet beta-cell (pro)insulin biosynthesis, and thus, glucose-stimulated insulin release, delta-cell somatostatin secretion, and pancreatic cell proliferation and differentiation. It may further mediate oxidative stress-induced cell inflammation, apoptosis and fibrosis. Further exploration of this system would probably offer new insights into the pathogenesis of pancreatitis, diabetes, cystic fibrosis and pancreatic cancer formation. New therapeutic targets and strategies might thus be suggested.

  2. The physiology of a local renin–angiotensin system in the pancreas

    Science.gov (United States)

    Leung, Po Sing

    2007-01-01

    The systemic renin–angiotensin system (RAS) plays an important role in regulating blood pressure, electrolyte and fluid homeostasis. However, local RASs also exist in diverse tissues and organs, where they play a multitude of autocrine, paracrine and intracrine physiological roles. The existence of a local RAS is now recognized in pancreatic acinar, islet, duct, endothelial and stellate cells, the expression of which is modulated in response to physiological and pathophysiological stimuli such as hypoxia, pancreatitis, islet transplantation, hyperglycaemia, and diabetes mellitus. This pancreatic RAS has been proposed to have important endocrine and exocrine roles in the pancreas, regulating local blood flow, duct cell sodium bicarbonate secretion, acinar cell digestive enzyme secretion, islet beta-cell (pro)insulin biosynthesis, and thus, glucose-stimulated insulin release, delta-cell somatostatin secretion, and pancreatic cell proliferation and differentiation. It may further mediate oxidative stress-induced cell inflammation, apoptosis and fibrosis. Further exploration of this system would probably offer new insights into the pathogenesis of pancreatitis, diabetes, cystic fibrosis and pancreatic cancer formation. New therapeutic targets and strategies might thus be suggested. PMID:17218353

  3. Cancer Stem Cells, EMT, and Developmental Pathway Activation in Pancreatic Tumors

    International Nuclear Information System (INIS)

    Hindriksen, Sanne; Bijlsma, Maarten F.

    2012-01-01

    Pancreatic cancer is a disease with remarkably poor patient survival rates. The frequent presence of metastases and profound chemoresistance pose a severe problem for the treatment of these tumors. Moreover, cross-talk between the tumor and the local micro-environment contributes to tumorigenicity, metastasis and chemoresistance. Compared to bulk tumor cells, cancer stem cells (CSC) have reduced sensitivity to chemotherapy. CSC are tumor cells with stem-like features that possess the ability to self-renew, but can also give rise to more differentiated progeny. CSC can be identified based on increased in vitro spheroid- or colony formation, enhanced in vivo tumor initiating potential, or expression of cell surface markers. Since CSC are thought to be required for the maintenance of a tumor cell population, these cells could possibly serve as a therapeutic target. There appears to be a causal relationship between CSC and epithelial-to-mesenchymal transition (EMT) in pancreatic tumors. The occurrence of EMT in pancreatic cancer cells is often accompanied by re-activation of developmental pathways, such as the Hedgehog, WNT, NOTCH, and Nodal/Activin pathways. Therapeutics based on CSC markers, EMT, developmental pathways, or tumor micro-environment could potentially be used to target pancreatic CSC. This may lead to a reduction of tumor growth, metastatic events, and chemoresistance in pancreatic cancer

  4. High-fat, carbohydrate-free diet markedly aggravates obesity but prevents beta-cell loss and diabetes in the obese, diabetes-susceptible db/db strain.

    Science.gov (United States)

    Mirhashemi, Farshad; Kluth, Oliver; Scherneck, Stephan; Vogel, Heike; Kluge, Reinhart; Schurmann, Annette; Joost, Hans-Georg; Neschen, Susanne

    2008-01-01

    We have previously reported that a high-fat, carbohydrate-free diet prevents diabetes and beta-cell destruction in the New Zealand Obese (NZO) mouse strain. Here we investigated the effect of diets with and without carbohydrates on obesity and development of beta-cell failure in a second mouse model of type 2 diabetes, the db/db mouse. When kept on a carbohydrate-containing standard (SD; with (w/w) 5.1, 58.3, and 17.6% fat, carbohydrates and protein, respectively) or high-fat diet (HFD; 14.6, 46.7 and 17.1%), db/db mice developed severe diabetes (blood glucose >20 mmol/l, weight loss, polydipsia and polyurea) associated with a selective loss of pancreatic beta-cells, reduced GLUT2 expression in the remaining beta-cells, and reduced plasma insulin levels. In contrast, db/db mice kept on a high-fat, carbohydrate-free diet (CFD; with 30.2 and 26.4% (w/w) fat or protein) did not develop diabetes and exhibited near-normal, hyperplastic islets in spite of a morbid obesity (fat content >60%) associated with hyperinsulinaemia. These data indicate that in genetically different mouse models of obesity-associated diabetes, obesity and dietary fat are not sufficient, and dietary carbohydrates are required, for beta-cell destruction.

  5. Radiosensitization effect of CMNa on hypoxic pancreatic cancer cell in vitro

    International Nuclear Information System (INIS)

    Yin Lijie; Zhang Li; Ding Tiangui; Peng Zhaoxiang; Yu Huan; Gao Yuwei

    2006-01-01

    Objective: To investigate the effects of glycodidazolum natrium (CMNa) on pancreatic cancer cells under hypoxic condition. Methods: The human pancreatic cancer Panc-1 cells were exposed to a single fraction of high-dose γ-ray radiation either with CMNa or under hypoxic condition. The percentage of dead cells was detected with a multiwell plated reader, and fluorescence intensities of propidium iodide were measured before and after digitonin treatment. The sensitizing effect of CMNa on cell killing induced by high-dose irradiation was evaluated by time and concentration dependence. The selective radiosensitive effect of CMNa on hypoxia was evaluated by flow cytometry. Results: The death rate of pancreatic cancer Panc-1 cells paralleled with the increasing concentration of CMNa under hypoxic condition after 30 gray irradiation. The selective radiosensitive effect of CMNa on hypoxia was time-dependent. Conclusions: CMNa can enhance the radiosensitivity of pancreatic cancer Pane-1 cells under hypoxic condition with high-dose irradiation. (authors)

  6. Control of Immune Cell Homeostasis and Function by lncRNAs.

    Science.gov (United States)

    Mowel, Walter K; Kotzin, Jonathan J; McCright, Sam J; Neal, Vanessa D; Henao-Mejia, Jorge

    2018-01-01

    The immune system is composed of diverse cell types that coordinate responses to infection and maintain tissue homeostasis. In each of these cells, extracellular cues determine highly specific epigenetic landscapes and transcriptional profiles to promote immunity while maintaining homeostasis. New evidence indicates that long non-coding RNAs (lncRNAs) play crucial roles in epigenetic and transcriptional regulation in mammals. Thus, lncRNAs have emerged as key regulatory molecules of immune cell gene expression programs in response to microbial and tissue-derived cues. We review here how lncRNAs control the function and homeostasis of cell populations during immune responses, emphasizing the diverse molecular mechanisms by which lncRNAs tune highly contextualized transcriptional programs. In addition, we discuss the new challenges faced in interrogating lncRNA mechanisms and function in the immune system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. A novel peptide sansalvamide analogue inhibits pancreatic cancer cell growth through G0/G1 cell-cycle arrest

    International Nuclear Information System (INIS)

    Ujiki, Michael B.; Milam, Ben; Ding Xianzhong; Roginsky, Alexandra B.; Salabat, M. Reza; Talamonti, Mark S.; Bell, Richard H.; Gu Wenxin; Silverman, Richard B.; Adrian, Thomas E.

    2006-01-01

    Patients with pancreatic cancer have little hope for cure because no effective therapies are available. Sansalvamide A is a cyclic depsipeptide produced by a marine fungus. We investigated the effect of a novel sansalvamide A analogue on growth, cell-cycle phases, and induction of apoptosis in human pancreatic cancer cells in vitro. The sansalvamide analogue caused marked time- and concentration-dependent inhibition of DNA synthesis and cell proliferation of two human pancreatic cancer cell lines (AsPC-1 and S2-013). The analogue induced G0/G1 phase cell-cycle arrest and morphological changes suggesting induction of apoptosis. Apoptosis was confirmed by annexin V binding. This novel sansalvamide analogue inhibits growth of pancreatic cancer cells through G0/G1 arrest and induces apoptosis. Sansalvamide analogues may be valuable for the treatment of pancreatic cancer

  8. Framework for Interpretation of Trypsin–antitrypsin Imbalance and Genetic Heterogeneity in Pancreatitis

    Science.gov (United States)

    Lin, Kun; Gao, Feng; Chen, Qingquan; Liu, Qicai; Chen, Shu

    2015-01-01

    Early intracellular premature trypsinogen activation was interpreted as the key initiator of pancreatitis. When the balance in the homeostasis of trypsin and antitrypsin system is disequilibrated, elevated aggressive enzymes directly attack the pancreatic tissue, which leads to pancreatic destruction and inflammation. However, trypsin alone is not enough to cause complications in pancreatitis, which may play a crucial role in modulating signaling events in the initial phase of the disease. NFκB activation is the major inflammatory pathway involved in the occurrence and development of pancreatitis and it can be induced by intrapancreatic activation of trypsinogen. Synthesis of trypsinogen occurs in endoplasmic reticulum (ER), and ER stress is an important early acinar cell event. Components of ER stress response are known to be able to trigger cell death as well as NFκB signaling cascade. The strongest evidence supporting the trypsin-centered theory is that gene mutations, which lead to the generation of more trypsin, or reduce the activity of trypsin inhibitors or trypsin degradation, are associated with pancreatitis. Thus, trypsin–antitrypsin imbalance may be the first step leading to pancreatic autodigestion and inducing other pathways. Continued experimental studies are necessary to determine the specific relationships between trypsin–antitrypsin imbalance and genetic heterogeneity in pancreatitis. In this article, we review the latest advances that contributed to the understanding of the basic mechanisms behind the occurrence and development of pancreatitis with a focus on the interpretation of trypsin–antitrypsin imbalance and their relationships with other inflammation pathways. We additionally highlight genetic predispositions to pancreatitis and possible mechanisms associated with them. PMID:26228362

  9. File list: NoD.Pan.10.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Pan.10.AllAg.Pancreatic_cancer_cells mm9 No description Pancreas Pancreatic cancer... cells http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Pan.10.AllAg.Pancreatic_cancer_cells.bed ...

  10. Knockdown of ZFR suppresses cell proliferation and invasion of human pancreatic cancer

    Directory of Open Access Journals (Sweden)

    Xiaolan Zhao

    Full Text Available BACKGROUND: Zinc finger RNA binding protein (ZFR is involved in the regulation of growth and cancer development. However, little is known about ZFR function in pancreatic cancer. METHODS: Herein, to investigate whether ZFR is involved in tumor growth, Oncomine microarray data was firstly used to evaluate ZFR gene expression in human pancreatic tumors. Then short hairpin RNA (shRNA targeting ZFR was designed and delivered into PANC-1 pancreatic cancer cells to knock down ZFR expression. Cell viability, cell proliferation and cell cycle analysis after ZFR knockdown were determined by MTT, colony forming and FACS, respectively. In addition, cell migration and invasion were assessed using the Transwell system. RESULTS: The expression of ZFR was significantly higher in pancreatic tumors than normal pancreas tissues by Oncomine database analysis. Knockdown of ZFR by shRNA-expressing lentivirus significantly decreased the viability and invasion ability of pancreatic cancer cells. Moreover, FACS analysis showed that knockdown of ZFR in PANC-1 cells caused a significant cell cycle arrest at G0/G1 phase. Furthermore, knockdown of ZFR decreased the levels of CDK2, CDK4, CyclinA and CyclinD1 and enhanced the expression of p27, which has evidenced by qRT-PCR and Western blot analysis. CONCLUSIONS: Knockdown of ZFR might provide a novel alternative to targeted therapy of pancreatic cancer and deserves further investigation.

  11. Reconstituting development of pancreatic intraepithelial neoplasia from primary human pancreas duct cells

    OpenAIRE

    Lee, Jonghyeob; Snyder, Emily R.; Liu, Yinghua; Gu, Xueying; Wang, Jing; Flowers, Brittany M.; Kim, Yoo Jung; Park, Sangbin; Szot, Gregory L.; Hruban, Ralph H.; Longacre, Teri A.; Kim, Seung K.

    2017-01-01

    Development of systems that reconstitute hallmark features of human pancreatic intraepithelial neoplasia (PanINs), the precursor to pancreatic ductal adenocarcinoma, could generate new strategies for early diagnosis and intervention. However, human cell-based PanIN models with defined mutations are unavailable. Here, we report that genetic modification of primary human pancreatic cells leads to development of lesions resembling native human PanINs. Primary human pancreas duct cells harbouring...

  12. [Culture of pancreatic progenitor cells in hanging drop and on floating filter].

    Science.gov (United States)

    Ma, Feng-xia; Chen, Fang; Chi, Ying; Yang, Shao-guang; Lu, Shi-hong; Han, Zhong-chao

    2013-06-01

    To construct a method to culture pancreatic progenitor cells in hanging drop and on floating filter,and to examine if pancreatic progenitor cells can differentiate into mature endocrine cells with this method. Murine embryos at day 12.5 were isolated and digested into single cells,which were then cultured in hanging drop for 24h and formed spheres.Spheres were cultured on the filter for 6 days,which floated in the dish containing medium.During culture,the expressions of pancreas duodenum homeobox-1(PDX-1)and neurogenin3(Ngn3)were determined.The expressions of endocrine and exocrine markers,insulin,glucagon,and carboxypeptidase(CPA)were determined on day 7 by immunohistochemistry.Insulin secretion of spheres stimulated by glucose was detected by ELISA.The changes of pancreatic marker expressions during culture were monitored by real-time polymerase chain reaction(PCR). One day after the culture,there were still a large amount of PDX-1 positive cells in pancreatic spheres,and these cells proliferated.On day 3,high expression of Ngn3 was detected,and the Ngn3-positive cells did not proliferate.On day 7,The expressions of endocrine and exocrine markers in the differentiated pancreatic progenitor cells were detected,which were consistent with that in vivo.Insulin was secreted by spheres upon the stimulation of glucose. In hanging drop and on floating filter,pancreatic progenitor cells can differentiate into mature endocrine cells.

  13. Acute pancreatitis during sickle cell vaso-occlusive painful crisis.

    Science.gov (United States)

    Ahmed, Shahid; Siddiqui, Anita K; Siddiqui, Rina K; Kimpo, Miriam; Russo, Linda; Mattana, Joseph

    2003-07-01

    Sickle cell disease is characterized by chronic hemolytic anemia and vaso-occlusive painful crisis. The vascular occlusion in sickle cell disease is a complex process and accounts for the majority of the clinical manifestations of the disease. Abdominal pain is an important component of vaso-occlusive painful crisis and may mimic diseases such as acute appendicitis and cholecystitis. Acute pancreatitis is rarely included as a cause of abdominal pain in patients with sickle cell disease. When it occurs it may result form biliary obstruction, but in other instances it might be a consequence of microvessel occlusion causing ischemia. In this series we describe four cases of acute pancreatitis in patients with sickle cell disease apparently due to microvascular occlusion and ischemic injury to the pancreas. All patients responded to conservative management. Acute pancreatitis should be considered in the differential diagnosis of abdominal pain in patients with sickle cell disease. Copyright 2003 Wiley-Liss, Inc.

  14. Rapid effects of 17beta-estradiol on epithelial TRPV6 Ca2+ channel in human T84 colonic cells.

    LENUS (Irish Health Repository)

    Irnaten, Mustapha

    2008-11-01

    The control of calcium homeostasis is essential for cell survival and is of crucial importance for several physiological functions. The discovery of the epithelial calcium channel Transient Receptor Potential Vaniloid (TRPV6) in intestine has uncovered important Ca(2+) absorptive pathways involved in the regulation of whole body Ca(2+) homeostasis. The role of steroid hormone 17beta-estradiol (E(2)), in [Ca(2+)](i) regulation involving TRPV6 has been only limited at the protein expression levels in over-expressing heterologous systems. In the present study, using a combination of calcium-imaging, whole-cell patch-clamp techniques and siRNA technology to specifically knockdown TRPV6 protein expression, we were able to (i) show that TRPV6 is natively, rather than exogenously, expressed at mRNA and protein levels in human T84 colonic cells, (ii) characterize functional TRPV6 channels and (iii) demonstrate, for the first time, the rapid effects of E(2) in [Ca(2+)](i) regulation involving directly TRPV6 channels in T84 cells. Treatment with E(2) rapidly (<5 min) enhanced [Ca(2+)](i) and this increase was partially but significantly prevented when cells were pre-treated with ruthenium red and completely abolished in cells treated with siRNA specifically targeting TRPV6 protein expression. These results indicate that when cells are stimulated by E(2), Ca(2+) enters the cell through TRPV6 channels. TRPV6 channels in T84 cells contribute to the Ca(2+) entry\\/signalling pathway that is sensitive to 17beta-estradiol.

  15. File list: InP.Pan.05.AllAg.Pancreatic_cancer_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Pan.05.AllAg.Pancreatic_cancer_cells mm9 Input control Pancreas Pancreatic cancer... cells SRX174587 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Pan.05.AllAg.Pancreatic_cancer_cells.bed ...

  16. Neonatal pancreatic pericytes support β-cell proliferation

    Directory of Open Access Journals (Sweden)

    Alona Epshtein

    2017-10-01

    Conclusions: This study introduces pancreatic pericytes as regulators of neonatal β-cell proliferation. In addition to advancing current understanding of the physiological β-cell replication process, these findings could facilitate the development of protocols aimed at expending these cells as a potential cure for diabetes.

  17. Metabolomic and proteomic analysis of a clonal insulin-producing beta-cell line (INS-1 832/13).

    Science.gov (United States)

    Fernandez, Céline; Fransson, Ulrika; Hallgard, Elna; Spégel, Peter; Holm, Cecilia; Krogh, Morten; Wårell, Kristofer; James, Peter; Mulder, Hindrik

    2008-01-01

    Metabolites generated from fuel metabolism in pancreatic beta-cells control exocytosis of insulin, a process which fails in type 2 diabetes. To identify and quantify these metabolites, global and unbiased analysis of cellular metabolism is required. To this end, polar metabolites, extracted from the clonal 832/13 beta-cell line cultured at 2.8 and 16.7 mM glucose for 48 h, were derivatized followed by identification and quantification, using gas chromatography (GC) and mass spectrometry (MS). After culture at 16.7 mM glucose for 48 h, 832/13 beta-cells exhibited a phenotype reminiscent of glucotoxicity with decreased content and secretion of insulin. The metabolomic analysis revealed alterations in the levels of 7 metabolites derived from glycolysis, the TCA cycle and pentose phosphate shunt, and 4 amino acids. Principal component analysis of the metabolite data showed two clusters, corresponding to the cells cultured at 2.8 and 16.7 mM glucose, respectively. Concurrent changes in protein expression were analyzed by 2-D gel electrophoresis followed by LC-MS/MS. The identities of 86 spots corresponding to 75 unique proteins that were significantly different in 832/13 beta-cells cultured at 16.7 mM glucose were established. Only 5 of these were found to be metabolic enzymes that could be involved in the metabolomic alterations observed. Anticipated changes in metabolite levels in cells exposed to increased glucose were observed, while changes in enzyme levels were much less profound. This suggests that substrate availability, allosteric regulation, and/or post-translational modifications are more important determinants of metabolite levels than enzyme expression at the protein level.

  18. Extra-pancreatic invasion induces lipolytic and fibrotic changes in the adipose microenvironment, with released fatty acids enhancing the invasiveness of pancreatic cancer cells

    Science.gov (United States)

    Okumura, Takashi; Ohuchida, Kenoki; Sada, Masafumi; Abe, Toshiya; Endo, Sho; Koikawa, Kazuhiro; Iwamoto, Chika; Miura, Daisuke; Mizuuchi, Yusuke; Moriyama, Taiki; Nakata, Kohei; Miyasaka, Yoshihiro; Manabe, Tatsuya; Ohtsuka, Takao; Nagai, Eishi; Mizumoto, Kazuhiro; Oda, Yoshinao; Hashizume, Makoto; Nakamura, Masafumi

    2017-01-01

    Pancreatic cancer progression involves components of the tumor microenvironment, including stellate cells, immune cells, endothelial cells, and the extracellular matrix. Although peripancreatic fat is the main stromal component involved in extra-pancreatic invasion, its roles in local invasion and metastasis of pancreatic cancer remain unclear. This study investigated the role of adipose tissue in pancreatic cancer progression using genetically engineered mice (Pdx1-Cre; LSL-KrasG12D; Trp53R172H/+) and an in vitro model of organotypic fat invasion. Mice fed a high fat diet had significantly larger primary pancreatic tumors and a significantly higher rate of distant organ metastasis than mice fed a standard diet. In the organotypic fat invasion model, pancreatic cancer cell clusters were smaller and more elongated in shape and showed increased fibrosis. Adipose tissue-derived conditioned medium enhanced pancreatic cancer cell invasiveness and gemcitabine resistance, as well as inducing morphologic changes in cancer cells and increasing the numbers of lipid droplets in their cytoplasm. The concentrations of oleic, palmitoleic, and linoleic acids were higher in adipose tissue-derived conditioned medium than in normal medium, with these fatty acids significantly enhancing the migration of cancer cells. Mature adipocytes were smaller and the concentration of fatty acids in the medium higher when these cells were co-cultured with cancer cells. These findings indicate that lipolytic and fibrotic changes in peripancreatic adipose tissue enhance local invasiveness and metastasis via adipocyte-released fatty acids. Inhibition of fatty acid uptake by cancer cells may be a novel therapy targeting interactions between cancer and stromal cells. PMID:28407685

  19. Cannabinoids reduce markers of inflammation and fibrosis in pancreatic stellate cells.

    Directory of Open Access Journals (Sweden)

    Christoph W Michalski

    2008-02-01

    Full Text Available While cannabinoids have been shown to ameliorate liver fibrosis, their effects in chronic pancreatitis and on pancreatic stellate cells (PSC are unknown.The activity of the endocannabinoid system was evaluated in human chronic pancreatitis (CP tissues. In vitro, effects of blockade and activation of cannabinoid receptors on pancreatic stellate cells were characterized. In CP, cannabinoid receptors were detected predominantly in areas with inflammatory changes, stellate cells and nerves. Levels of endocannabinoids were decreased compared with normal pancreas. Cannabinoid-receptor-1 antagonism effectuated a small PSC phenotype and a trend toward increased invasiveness. Activation of cannabinoid receptors, however, induced de-activation of PSC and dose-dependently inhibited growth and decreased IL-6 and MCP-1 secretion as well as fibronectin, collagen1 and alphaSMA levels. De-activation of PSC was partially reversible using a combination of cannabinoid-receptor-1 and -2 antagonists. Concomitantly, cannabinoid receptor activation specifically decreased invasiveness of PSC, MMP-2 secretion and led to changes in PSC phenotype accompanied by a reduction of intracellular stress fibres.Augmentation of the endocannabinoid system via exogenously administered cannabinoid receptor agonists specifically induces a functionally and metabolically quiescent pancreatic stellate cell phenotype and may thus constitute an option to treat inflammation and fibrosis in chronic pancreatitis.

  20. Paneth cells, antimicrobial peptides and maintenance of intestinal homeostasis.

    Science.gov (United States)

    Bevins, Charles L; Salzman, Nita H

    2011-05-01

    Building and maintaining a homeostatic relationship between a host and its colonizing microbiota entails ongoing complex interactions between the host and the microorganisms. The mucosal immune system, including epithelial cells, plays an essential part in negotiating this equilibrium. Paneth cells (specialized cells in the epithelium of the small intestine) are an important source of antimicrobial peptides in the intestine. These cells have become the focus of investigations that explore the mechanisms of host-microorganism homeostasis in the small intestine and its collapse in the processes of infection and chronic inflammation. In this Review, we provide an overview of the intestinal microbiota and describe the cell biology of Paneth cells, emphasizing the composition of their secretions and the roles of these cells in intestinal host defence and homeostasis. We also highlight the implications of Paneth cell dysfunction in susceptibility to chronic inflammatory bowel disease.

  1. BGLAP is expressed in pancreatic cancer cells and increases their growth and invasion

    Directory of Open Access Journals (Sweden)

    Michalski Christoph W

    2007-12-01

    Full Text Available Abstract Background Bone gamma-carboxyglutamate protein (BGLAP; osteocalcin is a small, highly conserved molecule first identified in the mineralized matrix of bone. It has been implicated in the pathophysiology of various malignancies. In this study, we analyzed the expression and role of BGLAP in the normal human pancreas, chronic pancreatitis (CP, and pancreatic ductal adenocarcinoma (PDAC using quantitative RT-PCR, immunohistochemistry, immunocytochemistry and enzyme immunoassays, as well as cell proliferation and invasion assays. Gene silencing was carried out using specific siRNA molecules. Results Compared to the normal pancreas, BGLAP mRNA and protein levels were not significantly different in CP and PDAC tissues. BGLAP was faintly present in the cytoplasm of normal acinar cells but was strongly expressed in the cytoplasm and nuclei of tubular complexes and PanIN lesions of CP and PDAC tissues. Furthermore, BGLAP expression was found in the cancer cells in PDAC tissues as well as in 4 cultured pancreatic cancer cell lines. TNFalpha reduced BGLAP mRNA and protein expression levels in pancreatic cancer cell lines. In addition, BGLAP silencing led to reduction of both cell growth and invasion in those cells. Conclusion BGLAP is expressed in pancreatic cancer cells, where it potentially increases pancreatic cancer cell growth and invasion through autocrine and/or paracrine mechanisms.

  2. Unraveling the role of the ghrelin gene peptides in the endocrine pancreas.

    Science.gov (United States)

    Granata, Riccarda; Baragli, Alessandra; Settanni, Fabio; Scarlatti, Francesca; Ghigo, Ezio

    2010-09-01

    The ghrelin gene peptides include acylated ghrelin (AG), unacylated ghrelin (UAG), and obestatin (Ob). AG, mainly produced by the stomach, exerts its central and peripheral effects through the GH secretagogue receptor type 1a (GHS-R1a). UAG, although devoid of GHS-R1a-binding affinity, is an active peptide, sharing with AG many effects through an unknown receptor. Ob was discovered as the G-protein-coupled receptor 39 (GPR39) ligand; however, its physiological actions remain unclear. The endocrine pancreas is necessary for glucose homeostasis maintenance. AG, UAG, and Ob are expressed in both human and rodent pancreatic islets from fetal to adult life, and the pancreas is the major source of ghrelin in the perinatal period. GHS-R1a and GPR39 expression has been shown in beta-cells and islets, as well as specific binding sites for AG, UAG, and Ob. Ghrelin colocalizes with glucagon in alpha-islet cells, but is also uniquely expressed in epsilon-islet cells, suggesting a role in islet function and development. Indeed, AG, UAG, and Ob regulate insulin secretion in beta-cells and isolated islets, promote beta-cell proliferation and survival, inhibit beta-cell and human islet cell apoptosis, and modulate the expression of genes that are essential in pancreatic islet cell biology. They even induce beta-cell regeneration and prevent diabetes in streptozotocin-treated neonatal rats. The receptor(s) mediating their effects are not fully characterized, and a signaling crosstalk has been suggested. The present review summarizes the newest findings on AG, UAG, and Ob expression in pancreatic islets and the role of these peptides on beta-cell development, survival, and function.

  3. Ets transcription factor GABP controls T cell homeostasis and immunity.

    Science.gov (United States)

    Luo, Chong T; Osmanbeyoglu, Hatice U; Do, Mytrang H; Bivona, Michael R; Toure, Ahmed; Kang, Davina; Xie, Yuchen; Leslie, Christina S; Li, Ming O

    2017-10-20

    Peripheral T cells are maintained in the absence of vigorous stimuli, and respond to antigenic stimulation by initiating cell cycle progression and functional differentiation. Here we show that depletion of the Ets family transcription factor GA-binding protein (GABP) in T cells impairs T-cell homeostasis. In addition, GABP is critically required for antigen-stimulated T-cell responses in vitro and in vivo. Transcriptome and genome-wide GABP-binding site analyses identify GABP direct targets encoding proteins involved in cellular redox balance and DNA replication, including the Mcm replicative helicases. These findings show that GABP has a nonredundant role in the control of T-cell homeostasis and immunity.

  4. TGF-β Signaling Regulates Pancreatic β-Cell Proliferation through Control of Cell Cycle Regulator p27 Expression

    International Nuclear Information System (INIS)

    Suzuki, Tomoyuki; Dai, Ping; Hatakeyama, Tomoya; Harada, Yoshinori; Tanaka, Hideo; Yoshimura, Norio; Takamatsu, Tetsuro

    2013-01-01

    Proliferation of pancreatic β-cells is an important mechanism underlying β-cell mass adaptation to metabolic demands. Increasing β-cell mass by regeneration may ameliorate or correct both type 1 and type 2 diabetes, which both result from inadequate production of insulin by β-cells of the pancreatic islet. Transforming growth factor β (TGF-β) signaling is essential for fetal development and growth of pancreatic islets. In this study, we exposed HIT-T15, a clonal pancreatic β-cell line, to TGF-β signaling. We found that inhibition of TGF-β signaling promotes proliferation of the cells significantly, while TGF-β signaling stimulation inhibits proliferation of the cells remarkably. We confirmed that this proliferative regulation by TGF-β signaling is due to the changed expression of the cell cycle regulator p27. Furthermore, we demonstrated that there is no observed effect on transcriptional activity of p27 by TGF-β signaling. Our data show that TGF-β signaling mediates the cell-cycle progression of pancreatic β-cells by regulating the nuclear localization of CDK inhibitor, p27. Inhibition of TGF-β signaling reduces the nuclear accumulation of p27, and as a result this inhibition promotes proliferation of β-cells

  5. Radiosensitization of pancreatic cancer cells by 2',2'-difluoro-2'-deoxycytidine

    International Nuclear Information System (INIS)

    Lawrence, Theodore S.; Chang, Emily Y.; Hahn, Tina M.; Hertel, Larry W.; Shewach, Donna S.

    1996-01-01

    Purpose: We have reported that the deoxycytidine analog 2',2'-difluoro-2'-deoxycytidine (dFdCyd) is a potent radiosensitizer of HT29 human colon cancer cells probably through its effects on intracellular deoxyribonucleotide (dNTP) pools. Because dFdCyd has activity against pancreatic cancer in clinical trials, we wished to determine if dFdCyd would radiosensitize human pancreatic cancer cells. Methods and Materials: We assessed the effect of dFdCyd on radiation sensitivity of two human pancreatic cancer cell lines, Panc-1 and BxPC-3. To begin to investigate the mechanism of sensitization, we determined the effect of dFdCyd on dNTP pools and cell cycle distribution. Results: We found that dFdCyd produced radiation enhancement ratios of 1.7-1.8 under noncytotoxic conditions in both cell lines. Sensitization was not associated with intracellular levels of 2',2'-difluoro-2'-deoxycytidine triphosphate, the cytotoxic metabolite of dFdCyd, but occurred when dATP pools were depleted below the level of approximately 1 μM. Although both cell lines showed substantial cell cycle redistribution after drug treatment, the flow cytogram of the BxPC-3 cells would not, by itself, be anticipated to result in increased radiation sensitivity. Conclusions: These findings demonstrate that dFdCyd is a potent radiation sensitizer of human pancreatic cancer cells and support the development of a clinical protocol using combined dFdCyd and radiation therapy in the treatment of pancreatic cancer

  6. Honokiol protects pancreatic β cell against high glucose and intermittent hypoxia-induced injury by activating Nrf2/ARE pathway in vitro and in vivo.

    Science.gov (United States)

    Li, Chen-Guang; Ni, Chang-Lin; Yang, Min; Tang, Yun-Zhao; Li, Zhu; Zhu, Yan-Juan; Jiang, Zhen-Huan; Sun, Bei; Li, Chun-Jun

    2018-01-01

    Obstructive sleep apnea hypopnea syndrome (OSAHS) is associated with glucose intolerance, insulin resistance and type 2 diabetes mellitus (T2DM). Although several studies have revealed that intermittent hypoxia (IH) in OSAHS may further aggravate pancreatic β cell damage and promote the evolution of type 2 diabetes (T2DM) by increasing oxidative stress, the underlying mechanisms are unclear. Honokiol, a potent radical scavenger, has been demonstrated to ameliorate oxidative stress in many cases. The present study aimed to explore the potential mechanism of IH and diabetes synergistically damage and destruct the pancreatic β cell, examine the effects of honokiol on ameliorating pancreatic β cell injury in this context and explore the mechanism of such effects. High glucose (HG) cultured INS-1 cells were exposed to 50 μM of honokiol for 24, 48 and 72 h with or without IH intervention. T2DM rats were treated with honokiol and exposed to 80 s of IH followed by 160 s of normoxia for 8 weeks. The cell proliferation, apoptosis and oxidative stress were measured. Blood glucose, insulin, glucagon and HOMA-IR (Homeostasis model assessment -insulin resistence) were also detected, and the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were detected by immunofluorescence staining and western blotting. Honokiol can reduce oxidative stress, cytotoxicity and apoptosis in the INS-1 cells of rats receiving HG treatment or both HG and IH treatment. IH can further aggravate pancreas dysfunction, cause a marked elevation in fasting blood glucose, glucagon, HOMA-IR and oxidative stress levels in DM rats. In addition, honokiol can effectively activate the Nrf2/ARE pathway and reverse this pancreatic dysfunction in vivo and in vitro. These findings indicate that honokiol acts as a potent ROS scavenger via Nrf2/ARE pathway and effectively attenuates oxidative stress and improves pancreatic β cell function of DM rats under IH

  7. Defective glucose and lipid metabolism in human immunodeficiency virus-infected patients with lipodystrophy involve liver, muscle tissue and pancreatic beta-cells

    DEFF Research Database (Denmark)

    Haugaard, Steen B; Andersen, Ove; Dela, Flemming

    2005-01-01

    .01. Disposition index (i.e. first-phase insulin response to intravenous glucose multiplied by incremental glucose disposal) was reduced by 46% (P = 0.05) in LIPO compared with the combined groups of NONLIPO and NAIVE, indicating an impaired adaptation of beta-cell function to insulin resistance in LIPO...... of glucose metabolism, lipid metabolism and beta-cell function in lipodystrophic HIV-infected patients. METHODS: [3-3H]glucose was applied during euglycaemic hyperinsulinaemic clamps in association with indirect calorimetry in 43 normoglycaemic HIV-infected patients (18 lipodystrophic patients on HAART (LIPO......), 18 patients without lipodystrophy on HAART (NONLIPO) and seven patients who were naive to antiretroviral therapy (NAIVE) respectively). beta-cell function was evaluated by an intravenous glucose tolerance test. RESULTS: Compared with NONLIPO and NAIVE separately, LIPO displayed markedly reduced ratio...

  8. Calcium homeostasis in fly photoreceptor cells

    NARCIS (Netherlands)

    Oberwinkler, J

    2002-01-01

    In fly photoreceptor cells, two processes dominate the Ca2+ homeostasis: light-induced Ca2+ influx through members of the TRP family of ion channels, and Ca2+ extrusion by Na+/Ca2+ exchange.Ca2+ release from intracellular stores is quantitatively insignificant. Both, the light-activated channels and

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  13. Tenascin-C enhances pancreatic cancer cell growth and motility and affects cell adhesion through activation of the integrin pathway.

    Directory of Open Access Journals (Sweden)

    Igor Paron

    Full Text Available BACKGROUND: Pancreatic cancer (PDAC is characterized by an abundant fibrous tissue rich in Tenascin-C (TNC, a large ECM glycoprotein mainly synthesized by pancreatic stellate cells (PSCs. In human pancreatic tissues, TNC expression increases in the progression from low-grade precursor lesions to invasive cancer. Aim of this study was the functional characterization of the effects of TNC on biologic relevant properties of pancreatic cancer cells. METHODS: Proliferation, migration and adhesion assays were performed on pancreatic cancer cell lines treated with TNC or grown on a TNC-rich matrix. Stable transfectants expressing the large TNC splice variant were generated to test the effects of endogenous TNC. TNC-dependent integrin signaling was investigated by immunoblotting, immunofluorescence and pharmacological inhibition. RESULTS: Endogenous TNC promoted pancreatic cancer cell growth and migration. A TNC-rich matrix also enhanced migration as well as the adhesion to the uncoated growth surface of poorly differentiated cell lines. In contrast, adhesion to fibronectin was significantly decreased in the presence of TNC. The effects of TNC on cell adhesion were paralleled by changes in the activation state of paxillin and Akt. CONCLUSION: TNC affects proliferation, migration and adhesion of poorly differentiated pancreatic cancer cell lines and might therefore play a role in PDAC spreading and metastasis in vivo.

  14. Expression and significance of Axin2 in pancreatic cancer cells

    Directory of Open Access Journals (Sweden)

    ZHANG Tao

    2016-05-01

    Full Text Available ObjectiveTo investigate the expression of Axin2 in pancreatic cancer cells, and to observe the influence of Axin2 on the proliferation, invasion, and migration of human pancreatic cancer cells (PANC-1. MethodsQuantitative real-time PCR was used to measure the expression of Axin2 in pancreatic cancer cell lines with different invasive abilities (PANC-1, Mia PaCa-2, and BxPC-3 and immortalized normal pancreatic cells (H6C7. PANC-1 cells with low expression were transfected with over-expressed Axin2 plasmid by transient transfection. MTT assay, Transwell assay, and scratch assay were used to determine the proliferation, invasion, and migration of cells transfected with over-expressed Axin2. One-way analysis of variance was used for comparison between multiple groups, and SNK-q test was used for comparison between any two groups. ResultsThe relative expression levels of Axin2 in PANC-1, BxPC-3, Mia PaCa-2, and H6C7 cells were 0.13±0.01, 0.42±0.05, 0.24±0.011, and 1.00±0.00, respectively, and PANC-1 cells had the lowest expression level of Axin2, with significant differences compared with the other cells (all P<0.05. When PANC-1 cells were transfected with over-expressed Axin2 plasmid, the cells in the over-expression group had a significant increase in the expression level of Axin2 compared with those in the blank group and the negative control group (both P<0.05. Compared with those in the non-transfection group and the blank group, PANC-1 cells in the over-expression group showed significant reductions in the proliferation, invasion, and migration abilities. ConclusionThe expression of Axin2 is down-regulated in pancreatic cancer cell lines and decreases with the increasing invasion ability, suggesting the role of tumor suppressor gene. High expression of Axin2 can reduce the proliferation, invasion, and migration abilities of PANC-1 cells.

  15. Interleukin 6 protects pancreatic β cells from apoptosis by stimulation of autophagy.

    Science.gov (United States)

    Linnemann, Amelia K; Blumer, Joseph; Marasco, Michelle R; Battiola, Therese J; Umhoefer, Heidi M; Han, Jee Young; Lamming, Dudley W; Davis, Dawn Belt

    2017-09-01

    IL-6 is a pleiotropic cytokine with complex roles in inflammation and metabolic disease. The role of IL-6 as a pro- or anti-inflammatory cytokine is still unclear. Within the pancreatic islet, IL-6 stimulates secretion of the prosurvival incretin hormone glucagon-like peptide 1 (GLP-1) by α cells and acts directly on β cells to stimulate insulin secretion in vitro Uncovering physiologic mechanisms promoting β-cell survival under conditions of inflammation and stress can identify important pathways for diabetes prevention and treatment. Given the established role of GLP-1 in promoting β-cell survival, we hypothesized that IL-6 may also directly protect β cells from apoptosis. Herein, we show that IL-6 robustly activates signal transducer and activator of transcription 3 (STAT3), a transcription factor that is involved in autophagy. IL-6 stimulates LC3 conversion and autophagosome formation in cultured β cells. In vivo IL-6 infusion stimulates a robust increase in lysosomes in the pancreas that is restricted to the islet. Autophagy is critical for β-cell homeostasis, particularly under conditions of stress and increased insulin demand. The stimulation of autophagy by IL-6 is regulated via multiple complementary mechanisms including inhibition of mammalian target of rapamycin complex 1 (mTORC1) and activation of Akt, ultimately leading to increases in autophagy enzyme production. Pretreatment with IL-6 renders β cells resistant to apoptosis induced by proinflammatory cytokines, and inhibition of autophagy with chloroquine prevents the ability of IL-6 to protect from apoptosis. Importantly, we find that IL-6 can activate STAT3 and the autophagy enzyme GABARAPL1 in human islets. We also see evidence of decreased IL-6 pathway signaling in islets from donors with type 2 diabetes. On the basis of our results, we propose direct stimulation of autophagy as a novel mechanism for IL-6-mediated protection of β cells from stress-induced apoptosis.-Linnemann, A. K

  16. Emerging role of Hippo signalling in pancreatic biology: YAP re-expression and plausible link to islet cell apoptosis and replication.

    Science.gov (United States)

    Sharma, Anjana; Yerra, Veera Ganesh; Kumar, Ashutosh

    2017-02-01

    Diabetes mellitus is an ailment that develops when the functional capacity of the pancreas does not meet the metabolic requirements of the whole body, either due to insulin insufficiency or resistance to insulin action. Current therapies that control glycaemia are limited by their unwanted effects or their inability to prevent the development of long-term complications. Regeneration and replacement of beta cell therapies are shaping the goals of future management of diabetes. The Hippo pathway, first discovered in Drosophila melanogaster, plays a vital role in controlling the organ size. Nuclear recruitment of YAP/TAZ (Yes-associated protein/transcriptional co-activator with PDZ-binding motif), a mammalian analogue of Yorkie protein found in Drosophila, activates cell proliferation and inhibits apoptosis. YAP was found to regulate early pancreatic development followed by downregulation during Ngn3-specific endocrine lineage maturation corresponding to their mitotic quiescence. Recent evidences have shown that optimum modulation of upstream kinases in the Hippo signalling pathway may lead to apoptosis inhibition and renewal of progenitor as well as stem cells in case of tissue or cell injury. This article reviews the evidences linking the role of various components of the Hippo pathway to pancreatic regeneration. In particular, the focus is on the beneficial role of induced YAP expression and its nuclear distribution on apoptosis and replication of adult pancreatic β islets. This approach may be of immense significance towards our fight against diabetes; thus, more insightful research is warranted in the area of Hippo signalling pathway and its involvement in pancreatic regeneration. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

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  3. Incretin hormones and beta cell function in chronic pancreatitis

    DEFF Research Database (Denmark)

    Knop, Filip Krag

    2010-01-01

    insulinotropic incretin hormones: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). GLP-1 and GIP are secreted from the small intestines in response to ingestion of nutrients. The incretin defect of T2DM has been characterised by a virtually lost insulinotropic effect of GIP......, with and without pancreatic enzyme supplementation (PES), we observed preserved incretin responses as compared to matched healthy subjects; and, further, that PES increased postprandial incretin responses in these patients. This suggests not only that the secretion of incretin hormones is regulated by the mere...... effect of the incretin hormones in 8 patients with CP and normal glucose tolerance and in 8 patients with secondary DM, and observed that patients with CP and secondary DM exhibit an impaired insulinotropic effect of GIP, and that this most likely occurs as a consequence of the diabetic state...

  4. Salinomycin nanoparticles interfere with tumor cell growth and the tumor microenvironment in an orthotopic model of pancreatic cancer.

    Science.gov (United States)

    Daman, Zahra; Faghihi, Homa; Montazeri, Hamed

    2018-05-02

    Recently, salinomycin (SAL) has been reported to inhibit proliferation and induce apoptosis in various tumors. The aim of this study was to deliver SAL to orthotopic model of pancreatic cancer by the aid of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). The NPs were physico-chemically characterized and evaluated for cytotoxicity on luciferase-transduced AsPC-1 cells in vitro as well as implanted orthotopically into the pancreas of nude mice. SAL (3.5 mg/kg every other day) blocked tumor growth by 52% compared to the control group after 3 weeks of therapy. Western blotting of tumor protein extracts indicated that SAL treatment leads to up-regulation of E-cadherin, β-catenin, and transforming growth factor beta receptor (TGFβR) expressions in AsPC-1 orthotopic tumor. Noteworthy, immunofluorescence staining of adjacent tumor sections showed that treatment with SAL NPs cause significant apoptosis in the tumor cells rather than the stroma. Further investigations also revealed that TGFβR2 over-expression was induced in stroma cells after treatment with SAL NPs. These results highlight SAL-loaded PLGA NPs as a promising system for pancreatic cancer treatment, while the mechanistic questions need to be subsequently tested.

  5. Quantitative pancreatic β cell MRI using manganese-enhanced Look-Locker imaging and two-site water exchange analysis.

    Science.gov (United States)

    Antkowiak, Patrick F; Vandsburger, Moriel H; Epstein, Frederick H

    2012-06-01

    Pancreatic β-cell imaging would be useful in monitoring the progression of and therapies for diabetes. The purpose of this study was to develop and evaluate quantitative β-cell MRI using manganese (Mn(2+)) labeling of β cells, T1 mapping, and a two-site water exchange model. Normal, pharmacologically-treated, and severely diabetic mice underwent injection of MnCl(2). Pancreatic water proton T1 relaxation was measured using Look-Locker MRI, and two-site water exchange analysis was used to estimate model parameters including the intracellular water proton relaxation rate constant (R1(ic)) and the intracellular fraction as indicators of β-cell function and mass, respectively. Logarithmic plots of T1 relaxation revealed two distinct proton pools relaxing with different T1s, and the two-site water exchange model fit the measured T1 relaxation data better than a monoexponential model. The intracellular R1(ic) time course revealed the kinetics of β-cell Mn(2+) labeling. Pharmacological treatments with nifedipine, tolbutamide, and diazoxide altered R1(ic), indicating that beta cell function was a determinant of Mn(2+) uptake. Intracellular fraction was significantly higher in mice with normal β cell mass than in diabetic mice (14.9% vs. 14.4%, P exchange analysis of T1 relaxation of the Mn(2+)-enhanced pancreas is a promising method for quantifying β cell volume fraction and function. Copyright © 2011 Wiley-Liss, Inc.

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  11. File list: DNS.PSC.20.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.PSC.20.AllAg.mESC_derived_pancreatic_cells mm9 DNase-seq Pluripotent stem cell mESC derived panc...reatic cells SRX404487 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.PSC.20.AllAg.mESC_derived_pancreatic_cells.bed ...

  12. File list: DNS.PSC.05.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.PSC.05.AllAg.mESC_derived_pancreatic_cells mm9 DNase-seq Pluripotent stem cell mESC derived panc...reatic cells SRX404487 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.PSC.05.AllAg.mESC_derived_pancreatic_cells.bed ...

  13. Beta cell proliferation and growth factors

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis; Svensson, C; Møldrup, Annette

    1999-01-01

    Formation of new beta cells can take place by two pathways: replication of already differentiated beta cells or neogenesis from putative islet stem cells. Under physiological conditions both processes are most pronounced during the fetal and neonatal development of the pancreas. In adulthood little...... increase in the beta cell number seems to occur. In pregnancy, however, a marked hyperplasia of the beta cells is observed both in rodents and man. Increased mitotic activity has been seen both in vivo and in vitro in islets exposed to placental lactogen (PL), prolactin (PRL) and growth hormone (GH...... and activation of the tyrosine kinase JAK2 and the transcription factors STAT1 and 3. The activation of the insulin gene however also requires the distal part of the receptor and activation of calcium uptake and STAT5. In order to identify putative autocrine growth factors or targets for growth factors we have...

  14. Ca2+ signaling in pancreatic acinar cells: physiology and pathophysiology

    Directory of Open Access Journals (Sweden)

    O.H. Petersen

    2009-01-01

    Full Text Available The pancreatic acinar cell is a classical model for studies of secretion and signal transduction mechanisms. Because of the extensive endoplasmic reticulum and the large granular compartment, it has been possible - by direct measurements - to obtain considerable insights into intracellular Ca2+ handling under both normal and pathological conditions. Recent studies have also revealed important characteristics of stimulus-secretion coupling mechanisms in isolated human pancreatic acinar cells. The acinar cells are potentially dangerous because of the high intra-granular concentration of proteases, which become inappropriately activated in the human disease acute pancreatitis. This disease is due to toxic Ca2+ signals generated by excessive liberation of Ca2+ from both the endoplasmic reticulum and the secretory granules.

  15. Exocrine pancreatic insufficiency in diabetic patients: prevalence, mechanisms, and treatment.

    Science.gov (United States)

    Piciucchi, Matteo; Capurso, Gabriele; Archibugi, Livia; Delle Fave, Martina Maria; Capasso, Marina; Delle Fave, Gianfranco

    2015-01-01

    Pancreas is a doubled-entity organ, with both an exocrine and an endocrine component, reciprocally interacting in a composed system whose function is relevant for digestion, absorption, and homeostasis of nutrients. Thus, it is not surprising that disorders of the exocrine pancreas also affect the endocrine system and vice versa. It is well-known that patients with chronic pancreatitis develop a peculiar form of diabetes (type III), caused by destruction and fibrotic injury of islet cells. However, less is known on the influence of diabetes on pancreatic exocrine function. Pancreatic exocrine insufficiency (PEI) has been reported to be common in diabetics, with a prevalence widely ranging, in different studies, in both type I (25-74%) and type II (28-54%) diabetes. A long disease duration, high insulin requirement, and poor glycemic control seem to be risk factors for PEI occurrence. The impact of pancreatic exocrine replacement therapy on glycemic, insulin, and incretins profiles has not been fully elucidated. The present paper is aimed at reviewing published studies investigating the prevalence of PEI in diabetic patients and factors associated with its occurrence.

  16. Transplantation of bone marrow derived cells promotes pancreatic islet repair in diabetic mice

    International Nuclear Information System (INIS)

    Gao Xiaodong; Song Lujun; Shen Kuntang; Wang Hongshan; Niu Weixin; Qin Xinyu

    2008-01-01

    The transplantation of bone marrow (BM) derived cells to initiate pancreatic regeneration is an attractive but as-yet unrealized strategy. Presently, BM derived cells from green fluorescent protein transgenic mice were transplanted into diabetic mice. Repair of diabetic islets was evidenced by reduction of hyperglycemia, increase in number of islets, and altered pancreatic histology. Cells in the pancreata of recipient mice co-expressed BrdU and insulin. Double staining revealed β cells were in the process of proliferation. BrdU + insulin - PDX-1 + cells, Ngn3 + cells and insulin + glucagon + cells, which showed stem cells, were also found during β-cell regeneration. The majority of transplanted cells were mobilized to the islet and ductal regions. In recipient pancreas, transplanted cells simultaneously expressed CD34 but did not express insulin, PDX-1, Ngn3, Nkx2.2, Nkx6.1, Pax4, Pax6, and CD45. It is concluded that BM derived cells especially CD34 + cells can promote repair of pancreatic islets. Moreover, both proliferation of β cells and differentiation of pancreatic stem cells contribute to the regeneration of β cells

  17. Integrating physiological regulation with stem cell and tissue homeostasis

    Science.gov (United States)

    Nakada, Daisuke; Levi, Boaz P.; Morrison, Sean J.

    2015-01-01

    Summary Stem cells are uniquely able to self-renew, to undergo multilineage differentiation, and to persist throughout life in a number of tissues. Stem cells are regulated by a combination of shared and tissue-specific mechanisms and are distinguished from restricted progenitors by differences in transcriptional and epigenetic regulation. Emerging evidence suggests that other aspects of cellular physiology, including mitosis, signal transduction, and metabolic regulation also differ between stem cells and their progeny. These differences may allow stem cells to be regulated independently of differentiated cells in response to circadian rhythms, changes in metabolism, diet, exercise, mating, aging, infection, and disease. This allows stem cells to sustain homeostasis or to remodel relevant tissues in response to physiological change. Stem cells are therefore not only regulated by short-range signals that maintain homeostasis within their tissue of origin, but also by long-range signals that integrate stem cell function with systemic physiology. PMID:21609826

  18. The role of tumor cell-derived connective tissue growth factor (CTGF/CCN2) in pancreatic tumor growth.

    Science.gov (United States)

    Bennewith, Kevin L; Huang, Xin; Ham, Christine M; Graves, Edward E; Erler, Janine T; Kambham, Neeraja; Feazell, Jonathan; Yang, George P; Koong, Albert; Giaccia, Amato J

    2009-02-01

    Pancreatic cancer is highly aggressive and refractory to existing therapies. Connective tissue growth factor (CTGF/CCN2) is a fibrosis-related gene that is thought to play a role in pancreatic tumor progression. However, CCN2 can be expressed in a variety of cell types, and the contribution of CCN2 derived from either tumor cells or stromal cells as it affects the growth of pancreatic tumors is unknown. Using genetic inhibition of CCN2, we have discovered that CCN2 derived from tumor cells is a critical regulator of pancreatic tumor growth. Pancreatic tumor cells derived from CCN2 shRNA-expressing clones showed dramatically reduced growth in soft agar and when implanted s.c. We also observed a role for CCN2 in the growth of pancreatic tumors implanted orthotopically, with tumor volume measurements obtained by positron emission tomography imaging. Mechanistically, CCN2 protects cells from hypoxia-mediated apoptosis, providing an in vivo selection for tumor cells that express high levels of CCN2. We found that CCN2 expression and secretion was increased in hypoxic pancreatic tumor cells in vitro, and we observed colocalization of CCN2 and hypoxia in pancreatic tumor xenografts and clinical pancreatic adenocarcinomas. Furthermore, we found increased CCN2 staining in clinical pancreatic tumor tissue relative to stromal cells surrounding the tumor, supporting our assertion that tumor cell-derived CCN2 is important for pancreatic tumor growth. Taken together, these data improve our understanding of the mechanisms responsible for pancreatic tumor growth and progression, and also indicate that CCN2 produced by tumor cells represents a viable therapeutic target for the treatment of pancreatic cancer.

  19. Pancreatic cancer stimulates pancreatic stellate cell proliferation and TIMP-1 production through the MAP kinase pathway

    International Nuclear Information System (INIS)

    Yoshida, Seiya; Yokota, Tokuyasu; Ujiki, Michael; Ding Xianzhong; Pelham, Carolyn; Adrian, Thomas E.; Talamonti, Mark S.; Bell, Richard H.; Denham, Woody

    2004-01-01

    Pancreatic adenocarcinoma is characterized by an intense desmoplastic reaction that surrounds the tumor. Pancreatic stellate cells (PSCs) are thought to be responsible for production of this extracellular matrix. When activated, PSCs have a myofibroblast phenotype and produce not only components of the extracellular matrix including collagen, fibronectin, and laminin, but also matrix metalloproteinases and tissue inhibitors of metalloproteinases (TIMPs). Since PSCs are found in the stroma surrounding human pancreatic adenocarcinoma, we postulate that pancreatic cancer could impact PSC proliferation and TIMP-1 production. Rat PSCs were isolated and cultured. Isolated PSCs were exposed to PANC-1 conditioned medium (CM) and proliferation, activation of the mitogen-activated protein (MAP) kinase pathway, and TIMP-1 gene induction were determined. Exposure to PANC-1 CM increased PSC DNA synthesis, cell number, and TIMP-1 mRNA (real-time PCR) as well as activating the extracellular-regulated kinase (ERK) 1/2. Inhibition of ERK 1/2 phosphorylation (U0126) prevented the increases in growth and TIMP-1 expression. PANC-1 CM stimulates PSC proliferation and TIMP-1 through the MAP kinase (ERK 1/2) pathway

  20. Efficient generation of functional pancreatic β-cells from human induced pluripotent stem cells.

    Science.gov (United States)

    Yabe, Shigeharu G; Fukuda, Satsuki; Takeda, Fujie; Nashiro, Kiyoko; Shimoda, Masayuki; Okochi, Hitoshi

    2017-02-01

    Insulin-secreting cells have been generated from human embryonic or induced pluripotent stem cells (iPSCs) by mimicking developmental processes. However, these cells do not always secrete glucose-responsive insulin, one of the most important characteristics of pancreatic β-cells. We focused on the importance of endodermal differentiation from human iPSCs in order to obtain functional pancreatic β-cells. A six-stage protocol was established for the differentiation of human iPSCs to pancreatic β-cells using defined culture media without feeders or serum. The effects of CHIR99021, a selective glycogen synthase kinase-3β inhibitor, were examined in the presence of fibroblast growth factor 2, activin, and bone morphogenetic protein 4 (FAB) during definitive endodermal induction by immunostaining for SRY (sex determining region Y)-box 17 (SOX17) and Forkhead box protein A2 (FOXA2). Insulin secretion was compared between the last stage of monolayer culture and spheroid culture conditions. Cultured cells were transplanted under kidney capsules of streptozotocin-diabetic non-obese diabetic-severe combined immunodeficiency mice, and blood glucose levels were measured once a week. Immunohistochemical analyses were performed 4 and 12 weeks after transplantation. Addition of CHIR99021 (3 μmol/L) in the presence of FAB for 2 days improved endodermal cell viability, maintaining the high SOX17-positive rate. Spheroid formation after the endocrine progenitor stage showed more efficient insulin secretion than did monolayer culture. After cell transplantation, diabetic mice had lower blood glucose levels, and islet-like structures were detected in vivo. Functional pancreatic β-cells were generated from human iPSCs. Induction of definitive endoderm and spheroid formation may be key steps for producing these cells. © 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

  1. Concomitant alpha7 and beta2 nicotinic AChR subunit deficiency leads to impaired energy homeostasis and increased physical activity in mice.

    Science.gov (United States)

    Somm, Emmanuel; Guérardel, Audrey; Maouche, Kamel; Toulotte, Audrey; Veyrat-Durebex, Christelle; Rohner-Jeanrenaud, Françoise; Maskos, Uwe; Hüppi, Petra S; Schwitzgebel, Valérie M

    2014-05-01

    Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated cation channels well characterized in neuronal signal transmission. Moreover, recent studies have revealed nAChR expression in nonneuronal cell types throughout the body, including tissues involved in metabolism. In the present study, we screen gene expression of nAChR subunits in pancreatic islets and adipose tissues. Mice pancreatic islets present predominant expression of α7 and β2 nAChR subunits but at a lower level than in central structures. Characterization of glucose and energy homeostasis in α7β2nAChR(-/-) mice revealed no major defect in insulin secretion and sensitivity but decreased glycemia apparently unrelated to gluconeogenesis or glycogenolysis. α7β2nAChR(-/-) mice presented an increase in lean and bone body mass and a decrease in fat storage with normal body weight. These observations were associated with elevated spontaneous physical activity in α7β2nAChR(-/-) mice, mainly due to elevation in fine vertical (rearing) activity while their horizontal (ambulatory) activity remained unchanged. In contrast to α7nAChR(-/-) mice presenting glucose intolerance and insulin resistance associated to excessive inflammation of adipose tissue, the present metabolic phenotyping of α7β2nAChR(-/-) mice revealed a metabolic improvement possibly linked to the increase in spontaneous physical activity related to central β2nAChR deficiency. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Effect of taurine on the insuline secretion isolated by the pancreatic tissue of intact and irradiated rats

    Energy Technology Data Exchange (ETDEWEB)

    Dokshina, G A; Silaeva, T Yu [Tomskij Gosudarstvennyj Univ. (USSR). Nauchno-Issledovatel' skij Inst. Biologii i Biofiziki

    1976-05-01

    The whole-body irradiation of rats (700 rads) inhibits the secretory activity of insular pancreatic tissue. Administration of taurine (200 mg/kg), on the fifth day after irradiation, five times every second day normalizes the secretory function of pancreatic islands. In the experiments in vitro, taurine (1.5 and 3.0 mg/ml) stimulated hormone secretion. The stimulating action of the amino acid manifests itself when ..beta..-receptors are blocked by obsidane (0.5 ..mu..g/ml). It is suggested that insuline secretion by ..beta..-cells of pancreas is restored and enhanced by taurine not merely through the adenylatecyclase system; other ways are also possible.

  3. Exposure to the viral by-product dsRNA or Coxsackievirus B5 triggers pancreatic beta cell apoptosis via a Bim / Mcl-1 imbalance.

    Directory of Open Access Journals (Sweden)

    Maikel L Colli

    2011-09-01

    Full Text Available The rise in type 1 diabetes (T1D incidence in recent decades is probably related to modifications in environmental factors. Viruses are among the putative environmental triggers of T1D. The mechanisms regulating beta cell responses to viruses, however, remain to be defined. We have presently clarified the signaling pathways leading to beta cell apoptosis following exposure to the viral mimetic double-stranded RNA (dsRNA and a diabetogenic enterovirus (Coxsackievirus B5. Internal dsRNA induces cell death via the intrinsic mitochondrial pathway. In this process, activation of the dsRNA-dependent protein kinase (PKR promotes eIF2α phosphorylation and protein synthesis inhibition, leading to downregulation of the antiapoptotic Bcl-2 protein myeloid cell leukemia sequence 1 (Mcl-1. Mcl-1 decrease results in the release of the BH3-only protein Bim, which activates the mitochondrial pathway of apoptosis. Indeed, Bim knockdown prevented both dsRNA- and Coxsackievirus B5-induced beta cell death, and counteracted the proapoptotic effects of Mcl-1 silencing. These observations indicate that the balance between Mcl-1 and Bim is a key factor regulating beta cell survival during diabetogenic viral infections.

  4. L-Cysteine Administration Attenuates Pancreatic Fibrosis Induced by TNBS in Rats by Inhibiting the Activation of Pancreatic Stellate Cell

    Science.gov (United States)

    Hu, GuoYong; Shen, Jie; Wang, Feng; Xu, Ling; Dai, WeiQi; Xiong, Jie; Ni, JianBo; Guo, ChuanYong; Wan, Rong; Wang, XingPeng

    2012-01-01

    Background and Aims Recent studies have shown that activated pancreatic stellate cells (PSCs) play a major role in pancreatic fibrogenesis. We aimed to study the effect of L-cysteine administration on fibrosis in chronic pancreatitis (CP) induced by trinitrobenzene sulfonic acid (TNBS) in rats and on the function of cultured PSCs. Methods CP was induced by TNBS infusion into rat pancreatic ducts. L-cysteine was administrated for the duration of the experiment. Histological analysis and the contents of hydroxyproline were used to evaluate pancreatic damage and fibrosis. Immunohistochemical analysis of α-SMA in the pancreas was performed to detect the activation of PSCs in vivo. The collagen deposition related proteins and cytokines were determined by western blot analysis. DNA synthesis of cultured PSCs was evaluated by BrdU incorporation. We also evaluated the effect of L-cysteine on the cell cycle and cell activation by flow cytometry and immunocytochemistry. The expression of PDGFRβ, TGFβRII, collagen 1α1 and α-SMA of PSCs treated with different concentrations of L-cysteine was determined by western blot. Parameters of oxidant stress were evaluated in vitro and in vivo. Nrf2, NQO1, HO-1, IL-1β expression were evaluated in pancreas tissues by qRT-PCR. Results The inhibition of pancreatic fibrosis by L-cysteine was confirmed by histological observation and hydroxyproline assay. α-SMA, TIMP1, IL-1β and TGF-β1 production decreased compared with the untreated group along with an increase in MMP2 production. L-cysteine suppressed the proliferation and extracellular matrix production of PSCs through down-regulating of PDGFRβ and TGFβRII. Concentrations of MDA+4-HNE were decreased by L-cysteine administration along with an increase in GSH levels both in tissues and cells. In addition, L-cysteine increased the mRNA expression of Nrf2, NQO1 and HO-1 and reduced the expression of IL-1β in L-cysteine treated group when compared with control group. Conclusion L

  5. pH-sensitive K+ channel TREK-1 is a novel target in pancreatic cancer

    DEFF Research Database (Denmark)

    Sauter, Daniel Rafael Peter; Sørensen, Christiane Elisabeth; Rapedius, Markus

    2016-01-01

    Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers and new therapeutic targets are urgently needed. One of the hallmarks of cancer is changed pH-homeostasis and potentially pH-sensors may play an important role in cancer cell behavior. Two-pore potassium channels (K2P) are p...... proliferation and migration indicating that hyperpolarization of Vm attenuates cancer cell behavior. TREK-1 may therefore be a promising novel target for PDAC therapy....

  6. Galectin-4 Reduces Migration and Metastasis Formation of Pancreatic Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Ana I Belo

    Full Text Available Galectin-4 (Gal-4 is a member of the galectin family of glycan binding proteins that shows a significantly higher expression in cystic tumors of the human pancreas and in pancreatic adenocarcinomas compared to normal pancreas. However, the putative function of Gal-4 in tumor progression of pancreatic cancer is still incompletely understood. In this study the role of Gal-4 in cancer progression was investigated, using a set of defined pancreatic cancer cell lines, Pa-Tu-8988S (PaTu-S and Pa-Tu-8988T (PaTu-T, as a model. These two cell lines are derived from the same liver metastasis of a human primary pancreatic adenocarcinoma, but differ in their growth characteristics and metastatic capacity. We demonstrated that Gal-4 expression is high in PaTu-S, which shows poor migratory properties, whereas much lower Gal-4 levels are observed in the highly metastatic cell line PaTu-T. In PaTu-S, Gal-4 is found in the cytoplasm, but it is also secreted and accumulates at the membrane at sites of contact with neighboring cells. Moreover, we show that Gal-4 inhibits metastasis formation by delaying migration of pancreatic cancer cells in vitro using a scratch assay, and in vivo using zebrafish (Danio rerio as an experimental model. Our data suggest that Gal-4 may act at the cell-surface of PaTu-S as an adhesion molecule to prevent release of the tumor cells, but has in addition a cytosolic function by inhibiting migration via a yet unknown mechanism.

  7. Caveolin-1 mediated radioresistance of 3D grown pancreatic cancer cells

    International Nuclear Information System (INIS)

    Hehlgans, Stephanie; Eke, Iris; Storch, Katja; Haase, Michael; Baretton, Gustavo B.; Cordes, Nils

    2009-01-01

    Background and purpose: Resistance of pancreatic ductal adenocarcinoma (PDAC) to chemo- and radiotherapy is a major obstacle. The integral membrane protein Caveolin-1 (Cav-1) has been suggested as a potent target in human pancreatic carcinoma cells. Materials and methods: Human pancreatic tumor cells were examined in a three-dimensional (3D) cell culture model with regard to clonogenic survival, apoptosis, radiogenic DNA-double strand breaks and protein expression and phosphorylation under siRNA-mediated knockdown of Cav-1 without and in combination with irradiation (X-rays, 0-6 Gy). Immunohistochemistry was used to assess Cav-1 expression in biopsies from patients with PDAC. Results: Tumor cells in PDAC showed significantly higher Cav-1 expression relative to tumor stroma. Cav-1 knockdown significantly reduced β1 integrin expression and Akt phosphorylation, induced Caspase 3- and Caspase 8-dependent apoptosis and enhanced the radiosensitivity of 3D cell cultures. While cell cycling and Cav-1 promoter activity remained stable, Cav-1 knockdown-induced radiosensitization correlated with elevated numbers of residual DNA-double strand breaks. Conclusions: Our data strongly support the concept of Cav-1 as a potent target in pancreatic carcinoma cells due to radiosensitization and Cav-1 overexpression in tumor cells of PDAC. 3D cell cultures are powerful and useful tools for the testing of novel targeting strategies to optimize conventional radio- and chemotherapy regimes for PDAC.

  8. Dynamic thiol/disulphide homeostasis in patients with basal cell carcinoma.

    Science.gov (United States)

    Demirseren, Duriye Deniz; Cicek, Cagla; Alisik, Murat; Demirseren, Mustafa Erol; Aktaş, Akın; Erel, Ozcan

    2017-09-01

    The aim of this study is to measure and compare the dynamic thiol/disulphide homeostasis of patients with basal cell carcinoma and healthy subjects with a newly developed and original method. Thirty four patients attending our outpatient clinic and clinically and histopathologically diagnosed as nodular basal cell carcinoma, and age and gender matched 30 healthy individuals have been involved in the study. Thiol/disulphide homeostasis tests have been measured with a novel automatic spectrophotometric method developed and the results have been compared statistically. Serum native thiol and disulphide levels in the patient and control group show a considerable variance statistically (p = 0.028, 0.039, respectively). Total thiol levels do not reveal a considerable variation (p = 0.094). Disulphide/native thiol ratios and native thiol/total thiol ratios also show a considerable variance statistically (p = 0.012, 0.013, 0.010, respectively). Thiol disulphide homeostasis in patients with basal cell carcinoma alters in the way that disulphide gets lower and thiols get higher. Thiol/disulphide level is likely to have a role in basal cell carcinoma pathogenesis.

  9. Bridging the gap between protein carboxyl methylation and phospholipid methylation to understand glucose-stimulated insulin secretion from the pancreatic beta cell.

    Science.gov (United States)

    Kowluru, Anjaneyulu

    2008-01-15

    Recent findings have implicated post-translational modifications at C-terminal cysteines [e.g., methylation] of specific proteins [e.g., G-proteins] in glucose-stimulated insulin secretion [GSIS]. Furthermore, methylation at the C-terminal leucine of the catalytic subunit of protein phosphatase 2A [PP2Ac] has also been shown to be relevant for GSIS. In addition to these two classes of protein methyl transferases, a novel class of glucose-activated phospholipid methyl transferases have also been identified in the beta cell. These enzymes catalyze three successive methylations of phosphatidylethanolamine to yield phosphatidylcholine. The "newly formed" phosphatidylcholine is felt to induce alterations in the membrane fluidity, which might favor vesicular fusion with the plasma membrane for the exocytosis of insulin. The objectives of this commentary are to: (i) review the existing evidence on the regulation, by glucose and other insulin secretagogues, of post-translational carboxylmethylation [CML] of specific proteins in the beta cell; (ii) discuss the experimental evidence, which implicates regulation, by glucose and other insulin secretagogues, of phosphatidylethanolamine methylation in the islet beta cell; (iii) propose a model for potential cross-talk between the protein and lipid methylation pathways in the regulation of GSIS and (iv) highlight potential avenues for future research, including the development of specific pharmacological inhibitors to further decipher regulatory roles for these methylation reactions in islet beta cell function.

  10. Targeting senescence cells in pancreatic cancer | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Targeting senescence cells in pancreatic cancer. Cellular senescence is a programmed response to oncogenic (tumour-causing) stress that aims to halt the expansion of cells with malignant potential. It does this by stopping the proliferation of pre-cancerous lesions and recruitment of the immune system for their elimination.

  11. Reversible immortalization of Nestin-positive precursor cells from pancreas and differentiation into insulin-secreting cells

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Pei; Li, Li; Qi, Hui [The Clinical Medical Research Center, The Second Clinical Medical College (Shenzhen People' s Hospital), Jinan University, 518020 Shenzhen (China); Zhou, Han-xin [Department of General Surgery, First Hospital (Shenzhen Second People' s Hospital) of Shenzhen University, 518020 Shenzhen (China); Deng, Chun-yan [The Clinical Medical Research Center, The Second Clinical Medical College (Shenzhen People' s Hospital), Jinan University, 518020 Shenzhen (China); Li, Fu-rong, E-mail: frli62@yahoo.com [The Clinical Medical Research Center, The Second Clinical Medical College (Shenzhen People' s Hospital), Jinan University, 518020 Shenzhen (China); Shenzhen Institution of Gerontology, 518020 Shenzhen (China)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer The NPPCs from mouse pancreas were isolated. Black-Right-Pointing-Pointer Tet-on system for SV40 large in NPPCs was used to get RINPPCs. Black-Right-Pointing-Pointer The RINPPCs can undergo at least 80 population doublings without senescence. Black-Right-Pointing-Pointer The RINPPCs can be induced to differentiate into insulin-producing cells. Black-Right-Pointing-Pointer The combination of GLP-1 and sodium butyrate promoted the differentiation process. -- Abstract: Pancreatic stem cells or progenitor cells posses the ability of directed differentiation into pancreatic {beta} cells. However, these cells usually have limited proliferative capacity and finite lifespan in vitro. In the present study, Nestin-positive progenitor cells (NPPCs) from mouse pancreas that expressed the pancreatic stem cells or progenitor cell marker Nestin were isolated to obtain a sufficient number of differentiated pancreatic {beta} cells. Tet-on system for SV40 large T-antigen expression in NPPCs was used to achieve reversible immortalization. The reversible immortal Nestin-positive progenitor cells (RINPPCs) can undergo at least 80 population doublings without senescence in vitro while maintaining their biological and genetic characteristics. RINPPCs can be efficiently induced to differentiate into insulin-producing cells that contain a combination of glucagon-like peptide-1 (GLP-1) and sodium butyrate. The results of the present study can be used to explore transplantation therapy of type I diabetes mellitus.

  12. Generation of glucose-responsive functional islets with a three-dimensional structure from mouse fetal pancreatic cells and iPS cells in vitro.

    Directory of Open Access Journals (Sweden)

    Hiroki Saito

    Full Text Available Islets of Langerhans are a pancreatic endocrine compartment consisting of insulin-producing β cells together with several other hormone-producing cells. While some insulin-producing cells or immature pancreatic cells have been generated in vitro from ES and iPS cells, islets with proper functions and a three-dimensional (3D structure have never been successfully produced. To test whether islets can be formed in vitro, we first examined the potential of mouse fetal pancreatic cells. We found that E16.5 pancreatic cells, just before forming islets, were able to develop cell aggregates consisting of β cells surrounded by glucagon-producing α cells, a structure similar to murine adult islets. Moreover, the transplantation of these cells improved blood glucose levels in hyperglycemic mice. These results indicate that functional islets are formed in vitro from fetal pancreatic cells at a specific developmental stage. By adopting these culture conditions to the differentiation of mouse iPS cells, we developed a two-step system to generate islets, i.e. immature pancreatic cells were first produced from iPS cells, and then transferred to culture conditions that allowed the formation of islets from fetal pancreatic cells. The islets exhibited distinct 3D structural features similar to adult pancreatic islets and secreted insulin in response to glucose concentrations. Transplantation of the islets improved blood glucose levels in hyperglycemic mice. In conclusion, the two-step culture system allows the generation of functional islets with a 3D structure from iPS cells.

  13. Senescent intervertebral disc cells exhibit perturbed matrix homeostasis phenotype.

    Science.gov (United States)

    Ngo, Kevin; Patil, Prashanti; McGowan, Sara J; Niedernhofer, Laura J; Robbins, Paul D; Kang, James; Sowa, Gwendolyn; Vo, Nam

    2017-09-01

    Aging greatly increases the risk for intervertebral disc degeneration (IDD) as a result of proteoglycan loss due to reduced synthesis and enhanced degradation of the disc matrix proteoglycan (PG). How disc matrix PG homeostasis becomes perturbed with age is not known. The goal of this study is to determine whether cellular senescence is a source of this perturbation. We demonstrated that disc cellular senescence is dramatically increased in the DNA repair-deficient Ercc1 -/Δ mouse model of human progeria. In these accelerated aging mice, increased disc cellular senescence is closely associated with the rapid loss of disc PG. We also directly examine PG homeostasis in oxidative damage-induced senescent human cells using an in vitro cell culture model system. Senescence of human disc cells treated with hydrogen peroxide was confirmed by growth arrest, senescence-associated β-galactosidase activity, γH2AX foci, and acquisition of senescence-associated secretory phenotype. Senescent human disc cells also exhibited perturbed matrix PG homeostasis as evidenced by their decreased capacity to synthesize new matrix PG and enhanced degradation of aggrecan, a major matrix PG. of the disc. Our in vivo and in vitro findings altogether suggest that disc cellular senescence is an important driver of PG matrix homeostatic perturbation and PG loss. Published by Elsevier B.V.

  14. [Role of connective tissue growth factor (CTGF) in proliferation and migration of pancreatic cancer cells].

    Science.gov (United States)

    Bai, Yu-chun; Kang, Quan; Luo, Qing; Wu, Dao-qi; Ye, Wei-xia; Lin, Xue-mei; Zhao, Yong

    2011-10-01

    To explore the expression of connective tissue growth factor (CTGF) in pancreatic cancer and its influence on the proliferation and migration of cancer cells. The expression of CTGF in pancreatic cell line PANC-1 cells was analyzed by real-time PCR and in pancreatic carcinoma (50 cases) tissues by immunohistochemistry. The ability of proliferation and migration in vitro of PANC-1 cells was tested by MTT assay, scratch test and Boyden chamber test after the CTGF gene was overexpressed by Ad5-CTGF or silenced with Ad5-siCTGF transfection. CTGF was overexpressed in both pancreatic cancer cells and tissues. Overxpression of CTGF leads to increased proliferation and migration of PANC-1 cells. The CTGF-transfected PANC-1 cells showed apparent stronger proliferation ability and scratch-repair ability than that of empty vector controls. The results of Boyden chamber test showed that there were 34 cells/field (200× magnificantion) of the CTGF-transfected overexpressing cells, much more than the 11 cells/field of the empty vector control cells; and 6 cells/microscopic field of the Ad5-siCTGF-transfected silenced cells, much less than the 15 cells/field of the control cells. CTGF is overexpressed in both pancreatic cancer cells in vitro and in vivo, indicating that it may play an important role in the cell proliferation and migration in pancreatic cancer.

  15. Use of digitonin permeabilization for characterization of calcium incorporated into. beta. cells in response to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Wesslen, N [Uppsala Univ. (Sweden)

    1985-01-01

    ..beta.. cell-rich pancreatic islets were used to characterize /sup 45/Ca uptake into pools with different sensitivities to permeabilization with digitonin. The plasma and secretory granule membranes were among the membranes most sensitive to digitonin treatment whereas the mitochondria were more resistant. Most of the /sup 45/Ca incorporated in response to glucose was found in a fraction released after exposure to a high concentration of digitonin. The results suggest that glucose promotes active sequestration of calcium in mitochondria and that the uptake of /sup 45/Ca in the secretory granules in secondary to a raised cytosolic Ca/sup 2 +/ activity.

  16. Reactive Oxygen Species and Mitochondrial Homeostasis as Regulators of Stem Cell Fate and Function.

    Science.gov (United States)

    Tan, Darren Q; Suda, Toshio

    2018-07-10

    The precise role and impact of reactive oxygen species (ROS) in stem cells, which are essential for lifelong tissue homeostasis and regeneration, remain of significant interest to the field. The long-term regenerative potential of a stem cell compartment is determined by the delicate balance between quiescence, self-renewal, and differentiation, all of which can be influenced by ROS levels. Recent Advances: The past decade has seen a growing appreciation for the importance of ROS and redox homeostasis in various stem cell compartments, particularly those of hematopoietic, neural, and muscle tissues. In recent years, the importance of proteostasis and mitochondria in relation to stem cell biology and redox homeostasis has garnered considerable interest. Here, we explore the reciprocal relationship between ROS and stem cells, with significant emphasis on mitochondria as a core component of redox homeostasis. We discuss how redox signaling, involving cell-fate determining protein kinases and transcription factors, can control stem cell function and fate. We also address the impact of oxidative stress on stem cells, especially oxidative damage of lipids, proteins, and nucleic acids. We further discuss ROS management in stem cells, and present recent evidence supporting the importance of mitochondrial activity and its modulation (via mitochondrial clearance, biogenesis, dynamics, and distribution [i.e., segregation and transfer]) in stem cell redox homeostasis. Therefore, elucidating the intricate links between mitochondria, cellular metabolism, and redox homeostasis is envisioned to be critical for our understanding of ROS in stem cell biology and its therapeutic relevance in regenerative medicine. Antioxid. Redox Signal. 00, 000-000.

  17. Spiclomazine induces apoptosis associated with the suppression of cell viability, migration and invasion in pancreatic carcinoma cells.

    Directory of Open Access Journals (Sweden)

    Wenjing Zhao

    Full Text Available The effective treatment for pancreatic carcinoma remains critically needed. Herein, this current study showed that spiclomazine treatment caused a reduction in viability in pancreatic carcinoma cell lines CFPAC-1 and MIA PaCa-2 in vitro. It was notable in this regard that, compared with pancreatic carcinoma cells, normal human embryonic kidney (HEK-293 and liver (HL-7702 cells were more resistant to the antigrowth effect of spiclomazine. Biochemically, spiclomazine treatment regulated the expression of protein levels in the apoptosis related pathways. Consistent with this effect, spiclomazine reduced the mitochondria membrane potential, elevated reactive oxygen species, and activated caspase-3/9. In addition, a key finding from this study was that spiclomazine suppressed migration and invasion of cancer cells through down-regulation of MMP-2/9. Collectively, the proposed studies did shed light on the antiproliferation effect of spiclomazine on pancreatic carcinoma cell lines, and further clarified the mechanisms that spiclomazine induced apoptosis associated with the suppression of migration and invasion.

  18. Interleukin-15 stimulates natural killer cell-mediated killing of both human pancreatic cancer and stellate cells

    Science.gov (United States)

    Van Audenaerde, Jonas R.M.; De Waele, Jorrit; Marcq, Elly; Van Loenhout, Jinthe; Lion, Eva; Van den Bergh, Johan M.J.; Jesenofsky, Ralf; Masamune, Atsushi; Roeyen, Geert; Pauwels, Patrick; Lardon, Filip; Peeters, Marc; Smits, Evelien L.J.

    2017-01-01

    Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer-related death in Western countries with a 5-year survival rate below 5%. One of the hallmarks of this cancer is the strong desmoplastic reaction within the tumor microenvironment (TME), orchestrated by activated pancreatic stellate cells (PSC). This results in a functional and mechanical shield which causes resistance to conventional therapies. Aiming to overcome this resistance by tackling the stromal shield, we assessed for the first time the capacity of IL-15 stimulated natural killer (NK) cells to kill PSC and pancreatic cancer cells (PCC). The potency of IL-15 to promote NK cell-mediated killing was evaluated phenotypically and functionally. In addition, NK cell and immune checkpoint ligands on PSC were charted. We demonstrate that IL-15 activated NK cells kill both PCC and PSC lines (range 9-35% and 20-50%, respectively) in a contact-dependent manner and significantly higher as compared to resting NK cells. Improved killing of these pancreatic cell lines is, at least partly, dependent on IL-15 induced upregulation of TIM-3 and NKG2D. Furthermore, we confirm significant killing of primary PSC by IL-15 activated NK cells in an ex vivo autologous system. Screening for potential targets for immunotherapeutic strategies, we demonstrate surface expression of both inhibitory (PD-L1, PD-L2) and activating (MICA/B, ULBPs and Galectin-9) ligands on primary PSC. These data underscore the therapeutic potential of IL-15 to promote NK cell-mediated cytotoxicity as a treatment of pancreatic cancer and provide promising future targets to tackle remaining PSC. PMID:28915646

  19. Hedgehog Signaling Regulates Epithelial-Mesenchymal Transition in Pancreatic Cancer Stem-Like Cells

    Science.gov (United States)

    Wang, Feng; Ma, Ling; Zhang, Zhengkui; Liu, Xiaoran; Gao, Hongqiao; Zhuang, Yan; Yang, Pei; Kornmann, Marko; Tian, Xiaodong; Yang, Yinmo

    2016-01-01

    Hedgehog (Hh) signaling is crucially involved in tumorigenesis. This study aimed to assess the role of Hh signaling in the regulation of epithelial-mesenchymal transition (EMT), stemness properties and chemoresistance of human pancreatic Panc-1 cancer stem cells (CSCs). Panc-1 cells were transfected with recombinant lentiviral vectors to silence SMO and serum-free floating-culture system was used to isolate Panc-1 tumorspheres. The expression of CSC and EMT markers was detected by flow cytometry, real-time RT-PCR and Western blot analysis. Malignant behaviors of Panc-1 CSC were evaluated by tumorigenicity assays and nude mouse lung metastasis model. We found that tumorspheres derived from pancreatic cancer cell line Panc-1 possessed self-renewal, differentiation and stemness properties. Hh pathway and EMT were active in Panc-1 tumorspheres. Inhibition of Hh signaling by SMO knockdown inhibited self-renewal, EMT, invasion, chemoresistance, pulmonary metastasis, tumorigenesis of pancreatic CSCs. In conclusion, Hh signaling contributes to the maintenance of stem-like properties and chemoresistance of pancreatic CSC and promotes the tumorigenesis and metastasis of pancreatic cancer. Hh pathway is a potential molecular target for the development of therapeutic strategies for pancreatic CSCs. PMID:26918054

  20. Dipeptidyl peptidase-4 inhibitor, vildagliptin, inhibits pancreatic beta cell apoptosis in association with its effects suppressing endoplasmic reticulum stress in db/db mice.

    Science.gov (United States)

    Wu, Yan-ju; Guo, Xin; Li, Chun-jun; Li, Dai-qing; Zhang, Jie; Yang, Yiping; Kong, Yan; Guo, Hang; Liu, De-min; Chen, Li-ming

    2015-02-01

    Vildagliptin promotes beta cell survival by inhibiting cell apoptosis. It has been suggested that chronic ER (endoplasmic reticulum) stress triggers beta cell apoptosis. The objective of the study is to explore whether the pro-survival effect of vildagliptin is associated with attenuation of endoplasmic reticulum stress in islets of db/db mice. Vildagliptin was orally administered to db/db mice for 6 weeks, followed by evaluation of beta cell apoptosis by caspase3 activity and TUNEL staining method. Endoplasmic reticulum stress markers were determined with quantitative RT-PCR, immunohistochemistry and immunoblot analysis. After 6 weeks of treatment, vildagliptin treatment increased plasma active GLP-1 levels (22.63±1.19 vs. 11.69±0.44, Pvildagliptin treatment down-regulated several genes related to endoplasmic reticulum stress including TRIB3 (tribbles homolog 3) (15.9±0.4 vs. 33.3±1.7, ×10⁻³, PVildagliptin promoted beta cell survival in db/db mice in association with down-regulating markers of endoplasmic reticulum stress including TRIB3, ATF-4 as well as CHOP. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Pancreatic Stellate Cells Have Distinct Characteristics From Hepatic Stellate Cells and Are Not the Unique Origin of Collagen-Producing Cells in the Pancreas.

    Science.gov (United States)

    Yamamoto, Gen; Taura, Kojiro; Iwaisako, Keiko; Asagiri, Masataka; Ito, Shinji; Koyama, Yukinori; Tanabe, Kazutaka; Iguchi, Kohta; Satoh, Motohiko; Nishio, Takahiro; Okuda, Yukihiro; Ikeno, Yoshinobu; Yoshino, Kenji; Seo, Satoru; Hatano, Etsuro; Uemoto, Shinji

    2017-10-01

    The origin of collagen-producing myofibroblasts in pancreatic fibrosis is still controversial. Pancreatic stellate cells (PSCs), which have been recognized as the pancreatic counterparts of hepatic stellate cells (HSCs), are thought to play an important role in the development of pancreatic fibrosis. However, sources of myofibroblasts other than PSCs may exist because extensive studies of liver fibrosis have uncovered myofibroblasts that did not originate from HSCs. This study aimed to characterize myofibroblasts in an experimental pancreatic fibrosis model in mice. We used transgenic mice expressing green fluorescent protein via the collagen type I α1 promoter and induced pancreatic fibrosis with repetitive injections of cerulein. Collagen-producing cells that are negative for glial fibrillary acidic protein (ie, not derived from PSCs) exist in the pancreas. Pancreatic stellate cells had different characteristics from those of HSCs in a very small possession of vitamin A using mass spectrometry and a low expression of lecithin retinol acyltransferase. The microstructure of PSCs was entirely different from that of HSCs using flow cytometry and electron microscopy. Our study showed that characteristics of PSCs are different from those of HSCs, and myofibroblasts in the pancreas might be derived not only from PSCs but also from other fibrogenic cells.

  2. Hypoxic stellate cells of pancreatic cancer stroma regulate extracellular matrix fiber organization and cancer cell motility.

    Science.gov (United States)

    Sada, Masafumi; Ohuchida, Kenoki; Horioka, Kohei; Okumura, Takashi; Moriyama, Taiki; Miyasaka, Yoshihiro; Ohtsuka, Takao; Mizumoto, Kazuhiro; Oda, Yoshinao; Nakamura, Masafumi

    2016-03-28

    Desmoplasia and hypoxia in pancreatic cancer mutually affect each other and create a tumor-supportive microenvironment. Here, we show that microenvironment remodeling by hypoxic pancreatic stellate cells (PSCs) promotes cancer cell motility through alteration of extracellular matrix (ECM) fiber architecture. Three-dimensional (3-D) matrices derived from PSCs under hypoxia exhibited highly organized parallel-patterned matrix fibers compared with 3-D matrices derived from PSCs under normoxia, and promoted cancer cell motility by inducing directional migration of cancer cells due to the parallel fiber architecture. Microarray analysis revealed that procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) in PSCs was the gene that potentially regulates ECM fiber architecture under hypoxia. Stromal PLOD2 expression in surgical specimens of pancreatic cancer was confirmed by immunohistochemistry. RNA interference-mediated knockdown of PLOD2 in PSCs blocked parallel fiber architecture of 3-D matrices, leading to decreased directional migration of cancer cells within the matrices. In conclusion, these findings indicate that hypoxia-induced PLOD2 expression in PSCs creates a permissive microenvironment for migration of cancer cells through architectural regulation of stromal ECM in pancreatic cancer. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. File list: NoD.PSC.10.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  4. File list: NoD.PSC.20.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  5. File list: NoD.PSC.50.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  6. Tributyltin exposure at noncytotoxic doses dysregulates pancreatic β-cell function in vitro and in vivo.

    Science.gov (United States)

    Chen, Ya-Wen; Lan, Kuo-Cheng; Tsai, Jing-Ren; Weng, Te-I; Yang, Ching-Yao; Liu, Shing-Hwa

    2017-09-01

    Tributyltin (TBT) is an endocrine disruptor. TBT can be found in food and in human tissues and blood. Several animal studies revealed that organotins induced diabetes with decreased insulin secretion. The detailed effect and mechanism of TBT on pancreatic β-cell function still remain unclear. We investigated the effect and mechanism of TBT exposure at noncytotoxic doses relevant to human exposure on β-cell function in vitro and in vivo. The β-cell-derived RIN-m5F cells and pancreatic islets from mouse and human were treated with TBT (0.05-0.2 μM) for 0.5-4 h. Adult male mice were orally exposed to TBT (25 μg/kg/day) with or without antioxidant N-acetylcysteine (NAC) for 1-3 weeks. Assays for insulin secretion and glucose metabolism were carried out. Unlike previous studies, TBT at noncytotoxic concentrations significantly increased glucose-stimulated insulin secretion and intracellular Ca 2+ ([Ca 2+ ] i ) in β-cells. The reactive oxygen species (ROS) production and phosphorylation of protein kinase C (PKC-pan) and extracellular signal-regulated kinase (ERK)1/2 were also increased. These TBT-triggered effects could be reversed by antiestrogen ICI182780 and inhibitors of ROS, [Ca 2+ ] i , and PKC, but not ERK. Similarly, islets treated with TBT significantly increased glucose-stimulated insulin secretion, which could be reversed by ICI182780, NAC, and PKC inhibitor. Mice exposed to TBT for 3 weeks significantly increased blood glucose and plasma insulin and induced glucose intolerance and insulin resistance, which could be reversed by NAC. These findings suggest that low/noncytotoxic doses of TBT induce insulin dysregulation and disturb glucose homeostasis, which may be mediated through the estrogen receptor-regulated and/or oxidative stress-related signaling pathways.

  7. Effect of Protein Hydrolysates on Pancreatic Cancer Cells

    DEFF Research Database (Denmark)

    Ossum, Carlo G.; Andersen, Lisa Lystbæk; Nielsen, Henrik Hauch

    Effect of Fish Protein Hydrolysates on Pancreatic Cancer Cells Carlo G. Ossum1, Lisa Lystbæk Andersen2, Henrik Hauch Nielsen2, Else K. Hoffmann1, and Flemming Jessen2 1University of Copenhagen, Department of Biology, Denmark, 2Technical University of Denmark (DTU), National Food Institute, Denmark...... hydrolysates obtained by enzymatic hydrolysis on cancer cell proliferation. Skin and belly flap muscle from trout were hydrolysed with the unspecific proteases Alcalase, Neutrase, or UE1 (all from Novozymes, Bagsværd, Denmark) to a hydrolysis degree of 1-15%. The hydrolysates were tested for biological...... activities affecting cell proliferation and ability to modulate caspase activity in pancreatic cancer cells COLO357 and BxPC-3 in vitro. A number of the hydrolysates showed caspase promoting activity; in particular products containing muscle tissue, i.e. belly flap, were able to stimulate caspase activity...

  8. Proinsulin maturation disorder is a contributor to the defect of subsequent conversion to insulin in {beta}-cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jie, E-mail: jie.wang2@osumc.edu [Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, The Ohio State University, Columbus, OH (United States); Osei, Kwame [Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, The Ohio State University, Columbus, OH (United States)

    2011-07-22

    Highlights: {yields} Primary proinsulin maturation disorder is inherent in Ins2{sup +/Akita} islets/{beta}-cells. {yields} A consequence is the inefficient conversion of proinsulin to insulin. {yields} Post-translational defects occur as well in the involved PC1/3 and PC2 convertases. {yields} Proinsulin maturation chaos results in defects in the following conversion process. {yields} A link of the proinsulin maturation disorder and hyperproinsulinemia is suggested. -- Abstract: Disproportionate hyperproinsulinemia is an indicator of {beta}-cell dysfunction in diabetes and the basis underlying this abnormality remains obscure. Recently, we have found proinsulin is an aggregation-prone molecule inherent with a low relative folding rate and maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO) in normal {beta}-cells as a result of the integration of maturation and disposal processes. PIHO is susceptible to environmental and genetic influences. Perturbation of PIHO produces a number of toxic consequences with known association to {beta}-cell failure in diabetes. To explore whether the perturbation of PIHO has a link to disproportionate hyperproinsulinemia, we investigated proinsulin conversion and the involved prohormone convertase 1/3 (PC1/3) and 2 (PC2) in mouse Ins2{sup +/Akita} islets/{beta}-cells that preserve a primary PIHO disorder due to a mutation (C96Y) in the insulin 2 (Ins2) gene. Our metabolic-labeling studies found an increased ratio of proinsulin to insulin in the cellular or released proteins of Ins2{sup +/Akita} islets. Histological, metabolic-labeling, and RT-PCR analyses revealed decreases of the PC1/3 and PC2 immunoreactivities in the {beta}-cells of Ins2{sup +/Akita} islets in spite of no declines of these two convertases at the transcriptional and translational levels. Immunoblot analyses in cloned Ins2{sup +/Akita} {beta}-cells further confirmed the increased ratio of proinsulin

  9. Distribution of Pancreatic Polypeptide-secreting Endocrine Cells in Nondiabetic and Diabetic Cases.

    Science.gov (United States)

    Śliwińska-Mossoń, Mariola; Milnerowicz, Halina

    2017-07-01

    The aim of the study was to demonstrate the effects of cigarette smoking and ongoing inflammation in chronic pancreatitis on the functioning of pancreatic polypeptide (PP)-secreting cells and to determine the relationship between the occurrence of an increased number of PP cells in the pancreas, the change in their location, and the intensity of their inflammatory changes in the course of pancreatitis and diabetes. Samples of tissues from healthy persons and from patients were verified histopathologically, and then PP was localized by immunohistochemical staining using the monoclonal anti-human PP antibody. The histopathologic evaluation of the hormone expression intensity in tissue sections was carried out using the semiquantitative method and was calculated with digital image analysis. The present study showed a very strong PP expression in the pancreatic tissue (especially in the head of the pancreas) derived from smoking patients with diabetes. The increase in the percentage of cells in the PP islets, between the acinar cells in smoking patients with diabetes and a statistically significant increase in the expression of PP, indicates a pancreatic endocrine dysfunction and suggests that cigarette smoking has a negative impact on the organ's efficiency. Because of its properties, the PP appears to be a useful marker of the endocrine insufficiency of the pancreas and a specific prognostic parameter of developing diabetes due to chronic pancreatitis.

  10. CD166/ALCAM expression is characteristic of tumorigenicity and invasive and migratory activities of pancreatic cancer cells.

    Directory of Open Access Journals (Sweden)

    Kenji Fujiwara

    Full Text Available CD166, also known as activated leukocyte cell adhesion molecule (ALCAM, is expressed by various cells in several tissues including cancer. However, the role of CD166 in malignant tumors is controversial, especially in pancreatic cancer. This study aimed to clarify the role and significance of CD166 expression in pancreatic cancer.We performed immunohistochemistry and flow cytometry to analyze the expression of CD166 in surgical pancreatic tissues and pancreatic cancer cell lines. The differences between isolated CD166+ and CD166- pancreatic cancer cells were analyzed by invasion and migration assays, and in mouse xenograft models. We also performed quantitative RT-PCR and microarray analyses to evaluate the expression levels of CD166 and related genes in cultured cells.Immunohistochemistry revealed high expression of CD166 in pancreatic cancer tissues (12.2%; 12/98 compared with that in normal pancreas controls (0%; 0/17 (p = 0.0435. Flow cytometry indicated that CD166 was expressed in 33.8-70.2% of cells in surgical pancreatic tissues and 0-99.5% of pancreatic cancer cell lines. Invasion and migration assays demonstrated that CD166- pancreatic cancer cells showed stronger invasive and migratory activities than those of CD166+ cancer cells (p<0.05. On the other hand, CD166+ Panc-1 cells showed a significantly stronger colony formation activity than that of CD166- Panc-1 cells (p<0.05. In vivo analysis revealed that CD166+ cells elicited significantly greater tumor growth than that of CD166- cells (p<0.05 in both subcutaneous and orthotopic mouse tumor models. mRNA expression of the epithelial-mesenchymal transition activator Zeb1 was over-expressed in CD166- cells (p<0.001. Microarray analysis showed that TSPAN8 and BST2 were over-expressed in CD166+ cells, while BMP7 and Col6A1 were over-expressed in CD166- cells.CD166+ pancreatic cancer cells are strongly tumorigenic, while CD166- pancreatic cancer cells exhibit comparatively stronger

  11. A novel HDAC inhibitor, CG200745, inhibits pancreatic cancer cell growth and overcomes gemcitabine resistance.

    Science.gov (United States)

    Lee, Hee Seung; Park, Soo Been; Kim, Sun A; Kwon, Sool Ki; Cha, Hyunju; Lee, Do Young; Ro, Seonggu; Cho, Joong Myung; Song, Si Young

    2017-01-30

    Pancreatic cancer is predominantly lethal, and is primarily treated using gemcitabine, with increasing resistance. Therefore, novel agents that increase tumor sensitivity to gemcitabine are needed. Histone deacetylase (HDAC) inhibitors are emerging therapeutic agents, since HDAC plays an important role in cancer initiation and progression. We evaluated the antitumor effect of a novel HDAC inhibitor, CG200745, combined with gemcitabine/erlotinib on pancreatic cancer cells and gemcitabine-resistant pancreatic cancer cells. Three pancreatic cancer-cell lines were used to evaluate the antitumor effect of CG200745 combined with gemcitabine/erlotinib. CG200745 induced the expression of apoptotic proteins (PARP and caspase-3) and increased the levels of acetylated histone H3. CG200745 with gemcitabine/erlotinib showed significant growth inhibition and synergistic antitumor effects in vitro. In vivo, gemcitabine/erlotinib and CG200745 reduced tumor size up to 50%. CG200745 enhanced the sensitivity of gemcitabine-resistant pancreatic cancer cells to gemcitabine, and decreased the level of ATP-binding cassette-transporter genes, especially multidrug resistance protein 3 (MRP3) and MRP4. The novel HDAC inhibitor, CG200745, with gemcitabine/erlotinib had a synergistic anti-tumor effect on pancreatic cancer cells. CG200745 significantly improved pancreatic cancer sensitivity to gemcitabine, with a prominent antitumor effect on gemcitabine-resistant pancreatic cancer cells. Therefore, improved clinical outcome is expected in the future.

  12. Activated macrophages create lineage-specific microenvironments for pancreatic acinar- and β-cell regeneration in mice.

    Science.gov (United States)

    Criscimanna, Angela; Coudriet, Gina M; Gittes, George K; Piganelli, Jon D; Esni, Farzad

    2014-11-01

    Although the cells that contribute to pancreatic regeneration have been widely studied, little is known about the mediators of this process. During tissue regeneration, infiltrating macrophages debride the site of injury and coordinate the repair response. We investigated the role of macrophages in pancreatic regeneration in mice. We used a saporin-conjugated antibody against CD11b to reduce the number of macrophages in mice following diphtheria toxin receptor-mediated cell ablation of pancreatic cells, and evaluated the effects on pancreatic regeneration. We analyzed expression patterns of infiltrating macrophages after cell-specific injury or from the pancreas of nonobese diabetic mice. We developed an in vitro culture system to study the ability of macrophages to induce cell-specific regeneration. Depletion of macrophages impaired pancreatic regeneration. Macrophage polarization, as assessed by expression of tumor necrosis factor-α, interleukin 6, interleukin 10, and CD206, depended on the type of injury. The signals provided by polarized macrophages promoted lineage-specific generation of acinar or endocrine cells. Macrophage from nonobese diabetic mice failed to provide signals necessary for β-cell generation. Macrophages produce cell type-specific signals required for pancreatic regeneration in mice. Additional study of these processes and signals might lead to new approaches for treating type 1 diabetes or pancreatitis. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

  13. Short-chain C6 ceramide sensitizes AT406-induced anti-pancreatic cancer cell activity

    International Nuclear Information System (INIS)

    Zhao, Xiaoguang; Sun, Baoyou; Zhang, Jingjing; Zhang, Ruishen; Zhang, Qing

    2016-01-01

    Our previous study has shown that AT406, a first-in-class small molecular antagonist of IAPs (inhibitor of apoptosis proteins), inhibits pancreatic cancer cell proliferation in vitro and in vivo. The aim of this research is to increase AT406's sensitivity by adding short-chain C6 ceramide. We show that co-treatment of C6 ceramide dramatically potentiated AT406-induced caspase/apoptosis activation and cytotoxicity in established (Panc-1 and Mia-PaCa-2 lines) and primary human pancreatic cancer cells. Reversely, caspase inhibitors largely attenuated C6 ceramide plus AT406-induced above cancer cell death. Molecularly, C6 ceramide downregulated Bcl-2 to increase AT406's sensitivity in pancreatic cancer cells. Intriguingly, C6 ceramide-mediated AT406 sensitization was nullified with Bcl-2 shRNA knockdown or pretreatment of the Bcl-2 inhibitor ABT-737. In vivo, liposomal C6 ceramide plus AT406 co-administration dramatically inhibited Panc-1 xenograft tumor growth in severe combined immunodeficient (SCID) mice. The combined anti-tumor activity was significantly more potent than either single treatment. Expressions of IAPs (cIAP1/XIAP) and Bcl-2 were downregulated in Panc-1 xenografts with the co-administration. Together, we demonstrate that C6 ceramide sensitizes AT406-mediated anti-pancreatic cancer cell activity possibly via downregulating Bcl-2. - Highlights: • C6 ceramide dramatically potentiates AT406-induced pancreatic cancer cell death. • C6 ceramide facilitates AT406-induced pancreatic cancer cell apoptosis. • C6 ceramide downregulates Bcl-2 to increase AT406's sensitivity in pancreatic cancer cells. • Liposomal C6 ceramide enhances AT406-induced anti-pancreatic cancer activity in vivo.

  14. Glucose, other secretagogues, and nerve growth factor stimulate mitogen-activated protein kinase in the insulin-secreting beta-cell line, INS-1

    DEFF Research Database (Denmark)

    Frödin, M; Sekine, N; Roche, E

    1995-01-01

    The signaling pathways whereby glucose and hormonal secretagogues regulate insulin-secretory function, gene transcription, and proliferation of pancreatic beta-cells are not well defined. We show that in the glucose-responsive beta-cell line INS-1, major secretagogue-stimulated signaling pathways...... converge to activate 44-kDa mitogen-activated protein (MAP) kinase. Thus, glucose-induced insulin secretion was found to be associated with a small stimulatory effect on 44-kDa MAP kinase, which was synergistically enhanced by increased levels of intracellular cAMP and by the hormonal secretagogues......-1. Phorbol ester, an activator of protein kinase C, stimulated 44-kDa MAP kinase by both Ca(2+)-dependent and -independent pathways. Nerve growth factor, independently of changes in cytosolic Ca2+, efficiently stimulated 44-kDa MAP kinase without causing insulin release, indicating that activation...

  15. Essential role of the small GTPase Ran in postnatal pancreatic islet development.

    Directory of Open Access Journals (Sweden)

    Fang Xia

    Full Text Available The small GTPase Ran orchestrates pleiotropic cellular responses of nucleo-cytoplasmic shuttling, mitosis and subcellular trafficking, but whether deregulation of these pathways contributes to disease pathogenesis has remained elusive. Here, we generated transgenic mice expressing wild type (WT Ran, loss-of-function Ran T24N mutant or constitutively active Ran G19V mutant in pancreatic islet β cells under the control of the rat insulin promoter. Embryonic pancreas and islet development, including emergence of insulin(+ β cells, was indistinguishable in control or transgenic mice. However, by one month after birth, transgenic mice expressing any of the three Ran variants exhibited overt diabetes, with hyperglycemia, reduced insulin production, and nearly complete loss of islet number and islet mass, in vivo. Deregulated Ran signaling in transgenic mice, adenoviral over-expression of WT or mutant Ran in isolated islets, or short hairpin RNA (shRNA silencing of endogenous Ran in model insulinoma INS-1 cells, all resulted in decreased expression of the pancreatic and duodenal homeobox transcription factor, PDX-1, and reduced β cell proliferation, in vivo. These data demonstrate that a finely-tuned balance of Ran GTPase signaling is essential for postnatal pancreatic islet development and glucose homeostasis, in vivo.

  16. File list: InP.PSC.50.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  18. File list: InP.PSC.10.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.PSC.10.AllAg.mESC_derived_pancreatic_cells mm9 Input control Pluripotent stem cell mESC derived panc...reatic cells SRX146010,SRX146009 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.PSC.10.AllAg.mESC_derived_pancreatic_cells.bed ...

  19. File list: InP.PSC.05.AllAg.mESC_derived_pancreatic_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.PSC.05.AllAg.mESC_derived_pancreatic_cells mm9 Input control Pluripotent stem cell mESC derived panc...reatic cells SRX146010,SRX146009 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.PSC.05.AllAg.mESC_derived_pancreatic_cells.bed ...

  20. Suppression of EAE by oral tolerance is independent of endogenous IFN-beta whereas treatment with recombinant IFN-beta ameliorates EAE

    DEFF Research Database (Denmark)

    Liu, Yawei; Teige, Ingrid; Ericsson, Ida

    2010-01-01

    IFN-beta is anticipated to have an important function in mucosal tolerance, as it is one of the major cytokines produced by plasmacytoid dendritic cells, and has recently been suggested as central to the maintenance of mucosal homeostasis. Here, we have investigated whether oral tolerance is depe......, however this was not a prerequisite for establishment of oral tolerance.Immunology and Cell Biology advance online publication, 12 January 2010; doi:10.1038/icb.2009.111....