Expression and localization of regenerating gene I in a rat liver regeneration model

International Nuclear Information System (INIS)

Wang Jingshu; Koyota, Souichi; Zhou, Xiaoping; Ueno, Yasuharu; Ma Li; Kawagoe, Masami; Koizumi, Yukio; Okamoto, Hiroshi; Sugiyama, Toshihiro

2009-01-01

Regenerating gene (Reg) I has been identified as a regenerative/proliferative factor for pancreatic islet cells. We examined Reg I expression in the regenerating liver of a rat model that had been administered 2-acetylaminofluorene and treated with 70% partial hepatectomy (2-AAF/PH model), where hepatocyte and cholangiocyte proliferation was suppressed and the hepatic stem cells and/or hepatic progenitor cells were activated. In a detailed time course study of activation of hepatic stem cells in the 2-AAF/PH model, utilizing immunofluorescence staining with antibodies of Reg I and other cell-type-specific markers, we found that Reg I-expressing cells are present in the bile ductules and increased during regeneration. Reg I-expressing cells were colocalized with CK19, OV6, and AFP. These results demonstrate that Reg I is significantly upregulated in the liver of the 2-AAF/PH rat model, accompanied by the formation of bile ductules during liver regeneration.

Immunohistochemical analyses of cell cycle progression and gene expression of biliary epithelial cells during liver regeneration after partial hepatectomy of the mouse.

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Fukuda, Tatsuya; Fukuchi, Tomokazu; Yagi, Shinomi; Shiojiri, Nobuyoshi

2016-05-20

The liver has a remarkable regeneration capacity, and, after surgical removal of its mass, the remaining tissue undergoes rapid regeneration through compensatory growth of its constituent cells. Although hepatocytes synchronously proliferate under the control of various signaling molecules from neighboring cells, there have been few detailed analyses on how biliary cells regenerate for their cell population after liver resection. The present study was undertaken to clarify how biliary cells regenerate after partial hepatectomy of mice through extensive analyses of their cell cycle progression and gene expression using immunohistochemical and RT-PCR techniques. When expression of PCNA, Ki67 antigen, topoisomerase IIα and phosphorylated histone H3, which are cell cycle markers, was immunohistochemically examined during liver regeneration, hepatocytes had a peak of the S phase and M phase at 48-72 h after resection. By contrast, biliary epithelial cells had much lower proliferative activity than that of hepatocytes, and their peak of the S phase was delayed. Mitotic figures were rarely detectable in biliary cells. RT-PCR analyses of gene expression of biliary markers such as Spp1 (osteopontin), Epcam and Hnf1b demonstrated that they were upregulated during liver regeneration. Periportal hepatocytes expressed some of biliary markers, including Spp1 mRNA and protein. Some periportal hepatocytes had downregulated expression of HNF4α and HNF1α. Gene expression of Notch signaling molecules responsible for cell fate decision of hepatoblasts to biliary cells during development was upregulated during liver regeneration. Notch signaling may be involved in biliary regeneration.

Liver regeneration

NARCIS (Netherlands)

Chamuleau, R. A.; Bosman, D. K.

1988-01-01

Despite great advances in analysing hemodynamic, morphological and biochemical changes during the process of liver regeneration, the exact (patho)physiological mechanism is still unknown. A short survey of literature is given of the kinetics of liver regeneration and the significance of different

Towards a new therapy protocol for liver metastases. Effect of boron compounds and BNCT on normal liver regeneration

International Nuclear Information System (INIS)

Cardoso, Jorge E.; Heber, Elisa M.; Trivillin, Veronica A.

2006-01-01

The Taormina project developed a new method for BNCT treatment of multifocal unresectable liver metastases based on whole liver autograft. The Roffo Institute liver surgeons propose a new technique based on partial liver autograft that would pose less risk to the patient but would require significant healthy liver regeneration following BNCT. The aim of the present study was to assess the effect of BPA, GB-10 (Na 2 10 B 10 H 10 ) and (GB-10 + BPA) and of BNCT mediated by these boron compounds on normal liver regeneration in the Wistar rat. Normal liver regeneration, body weight, hemogram, liver and kidney function were assessed following partial hepatectomy post administration of BPA, GB-10 or (GB-10 + BPA) and post in vivo BNCT at the RA-6 Reactor. These end-points were evaluated 9 days following partial hepatectomy, the time at which complete liver regeneration occurs in untreated controls. The corresponding biodistribution studies were conducted to perform dosimetric calculations. BPA, GB-10 and (GB-10 + PBA) and in vivo BNCT mediated by these boron compounds in dose ranges compatible with therapy did not cause alterations in the outcome of normal liver regeneration, and did not induce alterations in body weight, hemogram, liver or kidney function. The experimental data available to date support the development of a new BNCT protocol for the treatment of liver metastases that requires the regeneration of normal liver past-BNCT. (author)

Impaired lipid accumulation in the liver of Tsc2-heterozygous mice during liver regeneration

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Obayashi, Yoko, E-mail: youko_oobayashi@ajinomoto.com [Department of Pathology, University of Washington School of Medicine, Seattle, WA (United States); Campbell, Jean S.; Fausto, Nelson [Department of Pathology, University of Washington School of Medicine, Seattle, WA (United States); Yeung, Raymond S. [Department of Surgery, University of Washington School of Medicine, Seattle, WA (United States)

2013-07-19

Highlights: •Tuberin phosphorylation correlated with mTOR activation in early liver regeneration. •Liver regeneration in the Tsc2+/− mice was not enhanced. •The Tsc2+/− livers failed to accumulate lipid bodies during liver regeneration. •Mortality rate increased in Tsc2+/− mice after partial hepatectomy. •Tuberin plays a critical role in hepatic lipid accumulation to support regeneration. -- Abstract: Tuberin is a negative regulator of mTOR pathway. To investigate the function of tuberin during liver regeneration, we performed 70% hepatectomy on wild-type and Tsc2+/− mice. We found the tuberin phosphorylation correlated with mTOR activation during early liver regeneration in wild-type mice. However, liver regeneration in the Tsc2+/− mice was not enhanced. Instead, the Tsc2+/− livers failed to accumulate lipid bodies, and this was accompanied by increased mortality. These findings suggest that tuberin plays a critical role in liver energy balance by regulating hepatocellular lipid accumulation during early liver regeneration. These effects may influence the role of mTORC1 on cell growth and proliferation.

Serial analysis of gene expression (SAGE) in rat liver regeneration

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Cimica, Velasco; Batusic, Danko; Haralanova-Ilieva, Borislava; Chen, Yonglong; Hollemann, Thomas; Pieler, Tomas; Ramadori, Giuliano

2007-01-01

We have applied serial analysis of gene expression for studying the molecular mechanism of the rat liver regeneration in the model of 70% partial hepatectomy. We generated three SAGE libraries from a normal control liver (NL library: 52,343 tags), from a sham control operated liver (Sham library: 51,028 tags), and from a regenerating liver (PH library: 53,061 tags). By SAGE bioinformatics analysis we identified 40 induced genes and 20 repressed genes during the liver regeneration. We verified temporal expression of such genes by real time PCR during the regeneration process and we characterized 13 induced genes and 3 repressed genes. We found connective tissue growth factor transcript and protein induced very early at 4 h after PH operation before hepatocytes proliferation is triggered. Our study suggests CTGF as a growth factor signaling mediator that could be involved directly in the mechanism of liver regeneration induction

Understanding Liver Regeneration: From Mechanisms to Regenerative Medicine.

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Gilgenkrantz, Hélène; Collin de l'Hortet, Alexandra

2018-04-16

Liver regeneration is a complex and unique process. When two-thirds of a mouse liver is removed, the remaining liver recovers its initial weight in approximately 10 days. The understanding of the mechanisms responsible for liver regeneration may help patients needing large liver resections or transplantation and may be applied to the field of regenerative medicine. All differentiated hepatocytes are capable of self-renewal, but different subpopulations of hepatocytes seem to have distinct proliferative abilities. In the setting of chronic liver diseases, a ductular reaction ensues in which liver progenitor cells (LPCs) proliferate in the periportal region. Although these LPCs have the capacity to differentiate into hepatocytes and biliary cells in vitro, their ability to participate in liver regeneration is far from clear. Their expansion has even been associated with increased fibrosis and poorer prognosis in chronic liver diseases. Controversies also remain on their origin: lineage studies in experimental mouse models of chronic injury have recently suggested that these LPCs originate from hepatocyte dedifferentiation, whereas in other situations, they seem to come from cholangiocytes. This review summarizes data published in the past 5 years in the liver regeneration field, discusses the mechanisms leading to regeneration disruption in chronic liver disorders, and addresses the potential use of novel approaches for regenerative medicine. Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Follistatin allows efficient retroviral-mediated gene transfer into rat liver

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Borgnon, Josephine; Djamouri, Fatima; Lorand, Isabelle; Rico, Virginie Di; Loux, Nathalie; Pages, Jean-Christophe; Franco, Dominique; Capron, Frederique; Weber, Anne

2005-01-01

Retroviral vectors are widely used tools for gene therapy. However, in vivo gene transfer is only effective in dividing cells, which, in liver, requires a regenerative stimulus. Follistatin is effective in promoting liver regeneration after 90% and 70% hepatectomy in rats. We studied its efficacy on liver regeneration and retroviral-mediated gene delivery in 50% hepatectomized rats. When human recombinant follistatin was infused into the portal vein immediately after 50% hepatectomy, hepatocyte proliferation was significantly higher than in control 50% hepatectomized rats. A single injection of virus particles administered 23 h after follistatin infusion resulted in more than 20% gene transduction efficiency in hepatocytes compared to 3% in control rats. It is concluded that a single injection of follistatin induces onset of proliferation in 50% hepatectomized rats and allows efficient retroviral-mediated gene transfer to the liver

Role of liver progenitors in liver regeneration.

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Best, Jan; Manka, Paul; Syn, Wing-Kin; Dollé, Laurent; van Grunsven, Leo A; Canbay, Ali

2015-02-01

During massive liver injury and hepatocyte loss, the intrinsic regenerative capacity of the liver by replication of resident hepatocytes is overwhelmed. Treatment of this condition depends on the cause of liver injury, though in many cases liver transplantation (LT) remains the only curative option. LT for end stage chronic and acute liver diseases is hampered by shortage of donor organs and requires immunosuppression. Hepatocyte transplantation is limited by yet unresolved technical difficulties. Since currently no treatment is available to facilitate liver regeneration directly, therapies involving the use of resident liver stem or progenitor cells (LPCs) or non-liver stem cells are coming to fore. LPCs are quiescent in the healthy liver, but may be activated under conditions where the regenerative capacity of mature hepatocytes is severely impaired. Non-liver stem cells include embryonic stem cells (ES cells) and mesenchymal stem cells (MSCs). In the first section, we aim to provide an overview of the role of putative cytokines, growth factors, mitogens and hormones in regulating LPC response and briefly discuss the prognostic value of the LPC response in clinical practice. In the latter section, we will highlight the role of other (non-liver) stem cells in transplantation and discuss advantages and disadvantages of ES cells, induced pluripotent stem cells (iPS), as well as MSCs.

Bone morphogenetic protein 9 as a key regulator of liver progenitor cells in DDC-induced cholestatic liver injury.

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Addante, Annalisa; Roncero, Cesáreo; Almalé, Laura; Lazcanoiturburu, Nerea; García-Álvaro, María; Fernández, Margarita; Sanz, Julián; Hammad, Seddik; Nwosu, Zeribe C; Lee, Se-Jin; Fabregat, Isabel; Dooley, Steven; Ten Dijke, Peter; Herrera, Blanca; Sánchez, Aránzazu

2018-05-11

Bone morphogenetic protein 9 (BMP9) interferes with liver regeneration upon acute injury, while promoting fibrosis upon carbon tetrachloride-induced chronic injury. We have now addressed the role of BMP9 in 3,5 diethoxicarbonyl-1,4 dihydrocollidine (DDC)-induced cholestatic liver injury, a model of liver regeneration mediated by hepatic progenitor cell (known as oval cell), exemplified as ductular reaction and oval cell expansion. WT and BMP9KO mice were submitted to DDC diet. Livers were examined for liver injury, fibrosis, inflammation and oval cell expansion by serum biochemistry, histology, RT-qPCR and western blot. BMP9 signalling and effects in oval cells were studied in vitro using western blot and transcriptional assays, plus functional assays of DNA synthesis, cell viability and apoptosis. Crosslinking assays and short hairpin RNA approaches were used to identify the receptors mediating BMP9 effects. Deletion of BMP9 reduces liver damage and fibrosis, but enhances inflammation upon DDC feeding. Molecularly, absence of BMP9 results in overactivation of PI3K/AKT, ERK-MAPKs and c-Met signalling pathways, which together with an enhanced ductular reaction and oval cell expansion evidence an improved regenerative response and decreased damage in response to DDC feeding. Importantly, BMP9 directly targets oval cells, it activates SMAD1,5,8, decreases cell growth and promotes apoptosis, effects that are mediated by Activin Receptor-Like Kinase 2 (ALK2) type I receptor. We identify BMP9 as a negative regulator of oval cell expansion in cholestatic injury, its deletion enhancing liver regeneration. Likewise, our work further supports BMP9 as an attractive therapeutic target for chronic liver diseases. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Administration of multipotent mesenchymal stromal cells restores liver regeneration and improves liver function in obese mice with hepatic steatosis after partial hepatectomy.

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Ezquer, Fernando; Bahamonde, Javiera; Huang, Ya-Lin; Ezquer, Marcelo

2017-01-28

The liver has the remarkable capacity to regenerate in order to compensate for lost or damaged hepatic tissue. However, pre-existing pathological abnormalities, such as hepatic steatosis (HS), inhibits the endogenous regenerative process, becoming an obstacle for liver surgery and living donor transplantation. Recent evidence indicates that multipotent mesenchymal stromal cells (MSCs) administration can improve hepatic function and increase the potential for liver regeneration in patients with liver damage. Since HS is the most common form of chronic hepatic illness, in this study we evaluated the role of MSCs in liver regeneration in an animal model of severe HS with impaired liver regeneration. C57BL/6 mice were fed with a regular diet (normal mice) or with a high-fat diet (obese mice) to induce HS. After 30 weeks of diet exposure, 70% hepatectomy (Hpx) was performed and normal and obese mice were divided into two groups that received 5 × 10 5 MSCs or vehicle via the tail vein immediately after Hpx. We confirmed a significant inhibition of hepatic regeneration when liver steatosis was present, while the hepatic regenerative response was promoted by infusion of MSCs. Specifically, MSC administration improved the hepatocyte proliferative response, PCNA-labeling index, DNA synthesis, liver function, and also reduced the number of apoptotic hepatocytes. These effects may be associated to the paracrine secretion of trophic factors by MSCs and the hepatic upregulation of key cytokines and growth factors relevant for cell proliferation, which ultimately improves the survival rate of the mice. MSCs represent a promising therapeutic strategy to improve liver regeneration in patients with HS as well as for increasing the number of donor organs available for transplantation.

Replicative stress and alterations in cell cycle checkpoint controls following acetaminophen hepatotoxicity restrict liver regeneration.

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Viswanathan, Preeti; Sharma, Yogeshwar; Gupta, Priya; Gupta, Sanjeev

2018-03-05

Acetaminophen hepatotoxicity is a leading cause of hepatic failure with impairments in liver regeneration producing significant mortality. Multiple intracellular events, including oxidative stress, mitochondrial damage, inflammation, etc., signify acetaminophen toxicity, although how these may alter cell cycle controls has been unknown and was studied for its significance in liver regeneration. Assays were performed in HuH-7 human hepatocellular carcinoma cells, primary human hepatocytes and tissue samples from people with acetaminophen-induced acute liver failure. Cellular oxidative stress, DNA damage and cell proliferation events were investigated by mitochondrial membrane potential assays, flow cytometry, fluorescence staining, comet assays and spotted arrays for protein expression after acetaminophen exposures. In experimental groups with acetaminophen toxicity, impaired mitochondrial viability and substantial DNA damage were observed with rapid loss of cells in S and G2/M and cell cycle restrictions or even exit in the remainder. This resulted from altered expression of the DNA damage regulator, ATM and downstream transducers, which imposed G1/S checkpoint arrest, delayed entry into S and restricted G2 transit. Tissues from people with acute liver failure confirmed hepatic DNA damage and cell cycle-related lesions, including restrictions of hepatocytes in aneuploid states. Remarkably, treatment of cells with a cytoprotective cytokine reversed acetaminophen-induced restrictions to restore cycling. Cell cycle lesions following mitochondrial and DNA damage led to failure of hepatic regeneration in acetaminophen toxicity but their reversibility offers molecular targets for treating acute liver failure. © 2018 John Wiley & Sons Ltd.

CXC chemokines function as a rheostat for hepatocyte proliferation and liver regeneration.

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Gregory C Wilson

Full Text Available Our previous in vitro studies have demonstrated dose-dependent effects of CXCR2 ligands on hepatocyte cell death and proliferation. In the current study, we sought to determine if CXCR2 ligand concentration is responsible for the divergent effects of these mediators on liver regeneration after ischemia/reperfusion injury and partial hepatectomy.Murine models of partial ischemia/reperfusion injury and hepatectomy were used to study the effect of CXCR2 ligands on liver regeneration.We found that hepatic expression of the CXCR2 ligands, macrophage inflammatory protein-2 (MIP-2 and keratinocyte-derived chemokine (KC, was significantly increased after both I/R injury and partial hepatectomy. However, expression of these ligands after I/R injury was 30-100-fold greater than after hepatectomy. Interestingly, the same pattern of expression was found in ischemic versus non-ischemic liver lobes following I/R injury with expression significantly greater in the ischemic liver lobes. In both systems, lower ligand expression was associated with increased hepatocyte proliferation and liver regeneration in a CXCR2-dependent fashion. To confirm that these effects were related to ligand concentration, we administered exogenous MIP-2 and KC to mice undergoing partial hepatectomy. Mice received a "high" dose that replicated serum levels found after I/R injury and a "low" dose that was similar to that found after hepatectomy. Mice receiving the "high" dose had reduced levels of hepatocyte proliferation and regeneration whereas the "low" dose promoted hepatocyte proliferation and regeneration.Together, these data demonstrate that concentrations of CXC chemokines regulate the hepatic proliferative response and subsequent liver regeneration.

Oval cell response is attenuated by depletion of liver resident macrophages in the 2-AAF/partial hepatectomy rat.

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Shuai Xiang

Full Text Available BACKGROUND/AIMS: Macrophages are known to play an important role in hepatocyte mediated liver regeneration by secreting inflammatory mediators. However, there is little information available on the role of resident macrophages in oval cell mediated liver regeneration. In the present study we aimed to investigate the role of macrophages in oval cell expansion induced by 2-acetylaminofluorene/partial hepatectomy (2-AAF/PH in rats. METHODOLOGY/PRINCIPAL FINDINGS: We depleted macrophages in the liver of 2-AAF/PH treated rats by injecting liposome encapsulated clodronate 48 hours before PH. Regeneration of remnant liver mass, as well as proliferation and differentiation of oval cells were measured. We found that macrophage-depleted rats suffered higher mortality and liver transaminase levels. We also showed that depletion of macrophages yielded a significant decrease of EPCAM and PCK positive oval cells in immunohistochemical stained liver sections 9 days after PH. Meanwhile, oval cell differentiation was also attenuated as a result of macrophage depletion, as large foci of small basophilic hepatocytes were observed by day 9 following hepatectomy in control rats whereas they were almost absent in macrophage depleted rats. Accordingly, real-time polymerase chain reaction analysis showed lower expression of albumin mRNA in macrophage depleted livers. Then we assessed whether macrophage depletion may affect hepatic production of stimulating cytokines for liver regeneration. We showed that macrophage-depletion significantly inhibited hepatic expression of tumor necrosis factor-α and interleukin-6, along with a lack of signal transducer and activator of transcription 3 phosphorylation during the early period following hepatectomy. CONCLUSIONS: These data indicate that macrophages play an important role in oval cell mediated liver regeneration in the 2-AAF/PH model.

Influence of matrix nature on the functional efficacy of biomedical cell product for the regeneration of damaged liver (experimental model of acute liver failure

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S. V. Gautier

2017-01-01

Full Text Available Aim. A comparative analysis of the functional efficacy of biomedical cell products (BMCP for the regeneration of damaged liver based on biopolymer scaffolded porous and hydrogel matrices was performed on the experimental model of acute liver failure. Materials and methods. Matrices allowed for clinical use were employed for BMCP in the form of a sponge made from biopolymer nanostructured composite material (BNCM based on a highly purified bacterial copolymers of poly (β-hydroxybutyrate-co-β-oxyvalerate and polyethylene glycol and a hydrogel matrix from biopolymer microheterogeneous collagen-containing hydrogel (BMCH. Cellular component of BMCP was represented by liver cells and multipotent mesenchymal bone marrow stem cells. The functional efficacy of BMCP for the regeneration of damaged liver was evaluated on the experimental model of acute liver failure in Wistar rats (n = 40 via biochemical, morphological, and immunohistochemical methods. Results. When BMCP was implanted to regenerate the damaged liver on the basis of the scaffolded BNCM or hydrogel BMCH matrices, the lethality in rats with acute liver failure was absent; while in control it was 66.6%. Restoration of the activity of cytolytic enzyme levels and protein-synthetic liver function began on day 9 after modeling acute liver failure, in contrast to the control group, where recovery occurred only by days 18–21. Both matrices maintained the viability and functional activity of liver cells up to 90 days with the formation of blood vessels in BMCP. The obtained data confirm that scaffolded BNCM matrix and hydrogel BMCH matrix retain for a long time (up to 90 days the vital activity of the adherent cells in the BMCP composition, which allows using them to correct acute liver failure. At the same time, hydrogel matrix due to the presence of bioactive components contributes to the creation of the best conditions for adhesion and cell activity which accelerate the regeneration processes

The yield of genome mutations in cells of intact and regenerating rat liver in normal conditions and after γ-irradiation

International Nuclear Information System (INIS)

Gil'yano, N.Ya.; Malinovskij, O.V.

1984-01-01

A comparative study was made of spontaneus and induced polyploidy in cells of resting and regenerating rat liver. Polyploidy was shown to play a major role in the ontogenesis and during regeneration after partial hepatectomy. An essential difference was revealed in the radiation response of cells of intact and regenerating liver with respect to the yield of polyploid cells. This distinction was referped to different effectiveness of the processes of repair and fixation of radiation damages in the actively proliferating and resting cells

Delayed liver regeneration after partial hepatectomy in adiponectin knockout mice

International Nuclear Information System (INIS)

Ezaki, Hisao; Yoshida, Yuichi; Saji, Yukiko; Takemura, Takayo; Fukushima, Juichi; Matsumoto, Hitoshi; Kamada, Yoshihiro; Wada, Akira; Igura, Takumi; Kihara, Shinji; Funahashi, Tohru; Shimomura, Iichiro; Tamura, Shinji; Kiso, Shinichi; Hayashi, Norio

2009-01-01

We previously demonstrated that adiponectin has anti-fibrogenic and anti-inflammatory effects in the liver of mouse models of various liver diseases. However, its role in liver regeneration remains unclear. The aim of this study was to determine the role of adiponectin in liver regeneration. We assessed liver regeneration after partial hepatectomy in wild-type (WT) and adiponectin knockout (KO) mice. We analyzed DNA replication and various signaling pathways involved in cell proliferation and metabolism. Adiponectin KO mice exhibited delayed DNA replication and increased lipid accumulation in the regenerating liver. The expression levels of peroxisome proliferator-activated receptor (PPAR) α and carnitine palmitoyltransferase-1 (CPT-1), a key enzyme in mitochondrial fatty acid oxidation, were decreased in adiponectin KO mice, suggesting possible contribution of altered fat metabolism to these phenomena. Collectively, the present results highlight a new role for adiponectin in the process of liver regeneration.

Lung Regeneration: Endogenous and Exogenous Stem Cell Mediated Therapeutic Approaches.

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Akram, Khondoker M; Patel, Neil; Spiteri, Monica A; Forsyth, Nicholas R

2016-01-19

The tissue turnover of unperturbed adult lung is remarkably slow. However, after injury or insult, a specialised group of facultative lung progenitors become activated to replenish damaged tissue through a reparative process called regeneration. Disruption in this process results in healing by fibrosis causing aberrant lung remodelling and organ dysfunction. Post-insult failure of regeneration leads to various incurable lung diseases including chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis. Therefore, identification of true endogenous lung progenitors/stem cells, and their regenerative pathway are crucial for next-generation therapeutic development. Recent studies provide exciting and novel insights into postnatal lung development and post-injury lung regeneration by native lung progenitors. Furthermore, exogenous application of bone marrow stem cells, embryonic stem cells and inducible pluripotent stem cells (iPSC) show evidences of their regenerative capacity in the repair of injured and diseased lungs. With the advent of modern tissue engineering techniques, whole lung regeneration in the lab using de-cellularised tissue scaffold and stem cells is now becoming reality. In this review, we will highlight the advancement of our understanding in lung regeneration and development of stem cell mediated therapeutic strategies in combating incurable lung diseases.

Disruptive cell cycle regulation involving epigenetic downregulation of Cdkn2a (p16Ink4a) in early-stage liver tumor-promotion facilitating liver cell regeneration in rats

International Nuclear Information System (INIS)

Tsuchiya, Takuma; Wang, Liyun; Yafune, Atsunori; Kimura, Masayuki; Ohishi, Takumi; Suzuki, Kazuhiko; Mitsumori, Kunitoshi; Shibutani, Makoto

2012-01-01

Cell cycle aberration was immunohistochemically examined in relation to preneoplastic liver cell foci expressing glutathione S-transferase placental form (GST-P) at early stages of tumor-promotion in rats with thioacetamide (TAA), a hepatocarcinogen facilitating liver cell regeneration. Immunoexpression of p16 Ink4a following exposure to other hepatocarcinogens/promoters and its DNA methylation status were also analyzed during early and late tumor-promotion stages. GST-P + liver cell foci increased cell proliferation and decreased apoptosis when compared with surrounding liver cells. In concordance with GST-P + foci, checkpoint proteins at G 1 /S (p21 Cip1 , p27 Kip1 and p16 Ink4a ) and G 2 /M (phospho-checkpoint kinase 1, Cdc25c and phospho-Wee1) were either up- or downregulated. Cellular distribution within GST-P + foci was either increased or decreased with proteins related to G 2 -M phase or DNA damage (topoisomerase IIα, phospho-histone H2AX, phospho-histone H3 and Cdc2). In particular, p16 Ink4a typically downregulated in GST-P + foci and regenerative nodules at early tumor-promotion stage with hepatocarcinogens facilitating liver cell regeneration and in neoplastic lesions at late tumor-promotion stage with hepatocarcinogens/promoters irrespective of regenerating potential. Hypermethylation at exon 2 of Cdkn2a was detected at both early- and late-stages. Thus, diverse disruptive expression of G 1 /S and G 2 /M proteins, which allows for clonal selection of GST-P + foci, results in the acquisition of multiple aberrant phenotypes to disrupt checkpoint function. Moreover, increased DNA-damage responses within GST-P + foci may be the signature of genetic alterations. Intraexonic hypermethylation may be responsible for p16 Ink4a -downregulation, which facilitates cell cycle progression in early preneoplastic lesions produced by repeated cell regeneration and late-stage neoplastic lesions irrespective of the carcinogenic mechanism.

The genetic regulation of the terminating phase of liver regeneration

DEFF Research Database (Denmark)

Nygård, Ingvild E.; Mortensen, Kim E.; Hedegaard, Jakob

2012-01-01

Background After partial hepatectomy (PHx), the liver regeneration process terminates when the normal liver-mass/body-weight ratio of 2.5% has been re-established. To investigate the genetic regulation of the terminating phase of liver regeneration, we performed a 60% PHx in a porcine model. Liver...... biopsies were taken at the time of resection, after three weeks and upon termination the sixth week. Gene expression profiles were obtained using porcine oligonucleotide microarrays. Our study reveals the interactions between genes regulating the cell cycle, apoptosis and angiogenesis, and the role...... of Transforming Growth Factor-β (TGF-β) signalling towards the end of liver regeneration. Results Microarray analysis revealed a dominance of genes regulating apoptosis towards the end of regeneration. Caspase Recruitment Domain-Containing Protein 11 (CARD11) was up-regulated six weeks after PHx, suggesting...

Liver regeneration is dependent on the extent of hepatectomy

DEFF Research Database (Denmark)

Meier, Michelle; Knudsen, Anders Riegels; Andersen, Kasper Jarlhelt

of liver tissue and blood for liver specific serology. The change in liver weight after PH was evaluated as liver regeneration rate (RR). Histological analyses of liver cell proliferation and proteomic analyses are in progress. The gain in liver weight as well as RR increased significantly with the size......The upper limit for the size of hepatectomy is approximately 90% in rats. The present research project is designed to investigate the molecular pathways leading to either liver regeneration or liver failure after extended hepatectomy. In this first study we investigated the impact of different size...... of hepatectomy on liver regeneration in a rat model. Male Wistar rats were divided into four groups: 30% (n=24), 70% (n=24) and 90% (n=24) partial hepatectomy (PH) was performed together with a SHAM group (n=24). Euthanization took place at postoperative day (POD) 1 (n=8), 3 (n=8), and 5 (n=8) with harvesting...

The Effect of Elephantopus scaber L. on Liver Regeneration after Partial Hepatectomy

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Chin-Chuan Tsai

2013-01-01

Full Text Available Liver regeneration after partial hepatectomy (PHx is a physiological response for maintaining homeostasis. The aim of this study is to investigate effects of Elephantopus scaber L.- (ESL- induced liver regeneration on growth factors (HGF and IGF-1, cell cycle regulation, and apoptosis suppressed. In this study, we fed five Chinese medicinal herbs (1 g/kg/day, Codonopsis pilosula (CP, Dangshen, Salvia miltiorrhiza Bunge (SMB, Danshen,, Bupleurum kasi (BK, Chaihu, Elephantopus scaber L. (ESL, Teng-Khia-U, and Silymarin (Sm, 25 mg/kg for 7 days to male Spraue-Dawley rats. Then surgical 2/3 PHx was conducted and liver regeneration mechanisms were estimated on the following 24 hrs and 72 hrs. The activities of growth factors (HGF and IGF-I and cell cycle proteins were measured by Western blot and RT-PCR. Histological analysis and apoptosis were detected by H&E stain and TUNEL. The results showed that extraction of Elephantopus scaber L. (ESL and Silymarin (Sm, positive control were increased protein expression levels of HGF and IGF-1 which leads into cell cycle. These results suggest that the ESL plays a crucial role in cell cycle-induced liver regeneration and apoptosis. These results suggested that the ESL plays a crucial role in cell cycle-induced liver regeneration and suppressed hepatocytes apoptosis.

Progenitor cells in liver regeneration: molecular responses controlling their activation and expansion

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Santoni-Rugiu, Eric; Jelnes, Peter; Thorgeirsson, Snorri S

2005-01-01

created in the liver by a certain insult. This review will focus on molecular responses controlling activation and expansion of the hepatic progenitor cell niche, emphasizing similarities and differences in the microenvironments orchestrating regeneration by recruitment of progenitor cell populations...... cells, and recruited inflammatory cells as well as the variety of growth-modulating molecules produced and/or harboured by these elements. The cellular and molecular responses to different regenerative stimuli seem to depend on the injury inflicted and consequently on the molecular microenvironment...

Chronic stress does not impair liver regeneration in rats

DEFF Research Database (Denmark)

Andersen, Kasper J; Knudsen, Anders Riegels; Wiborg, Ove

2015-01-01

a 70 % partial hepatectomy (PHx). The animals were evaluated on postoperative day 2 or 4. Blood samples were collected to examine circulating markers of inflammation and liver cell damage. Additionally, liver tissues were sampled to evaluate liver weight and regeneration rate. RESULTS: None......BACKGROUND: Although wound healing is a simple regenerative process that is critical after surgery, it has been shown to be impaired under psychological stress. The liver has a unique capacity to regenerate through highly complex mechanisms. The aim of this study was to investigate the effects...... of chronic stress, which may induce a depression-like state, on the complex process of liver regeneration in rats. METHODS: Twenty rats were included in this study. The animals received either a standard housing protocol or were subjected to a Chronic Mild Stress (CMS) stress paradigm. All rats underwent...

Vitamin K2-enhanced liver regeneration is associated with oval cell expansion and up-regulation of matrilin-2 expression in 2-AAF/PH rat model.

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Lin, M; Sun, P; Zhang, G; Xu, X; Liu, G; Miao, H; Yang, Y; Xu, H; Zhang, L; Wu, P; Li, M

2014-03-01

Normal liver has a great potential of regenerative capacity after partial hepatectomy. In clinic, however, most patients receiving partial hepatectomy are usually suffering from chronic liver diseases with severely damaged hepatocyte population. Under these conditions, activation of hepatic progenitor cell (oval cell in rodents) population might be considered as an alternative mean to enhance liver functional recovery. Vitamin K2 has been shown to promote liver functional recovery in patients with liver cirrhosis. In this study, we explored the possibility of vitamin K2 treatment in activating hepatic oval cell for liver regeneration with the classic 2-acetamido-fluorene/partial hepatectomy (2-AAF/PH) model in Sprague-Dawley rats. In 2-AAF/PH animals, vitamin K2 treatment induced a dose-dependent increase of liver regeneration as assessed by the weight ratio of remnant liver versus whole body and by measuring serum albumin level. In parallel, a drastic expansion of oval cell population as assessed by anti-OV6 and anti-CK19 immunostaining was noticed in the periportal zone of the remnant liver. Since matrilin-2 was linked to oval cell proliferation and liver regeneration after partial hepatectomy, we assessed its expression at both the mRNA and protein levels. The results revealed a significant increase after vitamin K2 treatment in parallel with the expansion of oval cell population. Consistently, knocking down matrilin-2 expression in vivo largely reduced vitamin K2-induced liver regeneration and oval cell proliferation in 2-AAF/PH animals. In conclusion, these data suggest that vitamin K2 treatment enhances liver regeneration after partial hepatectomy, which is associated with oval cell expansion and matrilin-2 up-regulation.

Shear stress upregulates regeneration-related immediate early genes in liver progenitors in 3D ECM-like microenvironments.

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Nishii, Kenichiro; Brodin, Erik; Renshaw, Taylor; Weesner, Rachael; Moran, Emma; Soker, Shay; Sparks, Jessica L

2018-05-01

The role of fluid stresses in activating the hepatic stem/progenitor cell regenerative response is not well understood. This study hypothesized that immediate early genes (IEGs) with known links to liver regeneration will be upregulated in liver progenitor cells (LPCs) exposed to in vitro shear stresses on the order of those produced from elevated interstitial flow after partial hepatectomy. The objectives were: (1) to develop a shear flow chamber for application of fluid stress to LPCs in 3D culture; and (2) to determine the effects of fluid stress on IEG expression in LPCs. Two hours of shear stress exposure at ∼4 dyn/cm 2 was applied to LPCs embedded individually or as 3D spheroids within a hyaluronic acid/collagen I hydrogel. Results were compared against static controls. Quantitative reverse transcriptase polymerase chain reaction was used to evaluate the effect of experimental treatments on gene expression. Twenty-nine genes were analyzed, including IEGs and other genes linked to liver regeneration. Four IEGs (CFOS, IP10, MKP1, ALB) and three other regeneration-related genes (WNT, VEGF, EpCAM) were significantly upregulated in LPCs in response to fluid mechanical stress. LPCs maintained an early to intermediate stage of differentiation in spheroid culture in the absence of the hydrogel, and addition of the gel initiated cholangiocyte differentiation programs which were abrogated by the onset of flow. Collectively the flow-upregulated genes fit the pattern of an LPC-mediated proliferative/regenerative response. These results suggest that fluid stresses are potentially important regulators of the LPC-mediated regeneration response in liver. © 2017 Wiley Periodicals, Inc.

Hepatic regeneration after sublethal partial liver irradiation in cirrhotic rats

International Nuclear Information System (INIS)

Gu Ke; Lai Songtao; Ma Ningyi; Zhao Jiandong; Ren Zhigang; Wang Jian; Liu Jin; Jiang Guoliang

2011-01-01

Our previous animal study had demonstrated that partial liver irradiation (IR) could stimulate regeneration in the protected liver, which supported the measurements adopted in radiotherapy planning for hepatocellular carcinoma. The purpose of this present study is to investigate whether cirrhotic liver repopulation could be triggered by partial liver IR. The cirrhosis was induced by thioacetamide (TAA) in rats. After cirrhosis establishment, TAA was withdrawn. In Experiment 1, only right-half liver was irradiated with single doses of 5 Gy, 10 Gy and 15 Gy, respectively. In Experiment 2, right-half liver was irradiated to 15 Gy, and the left-half to 2.5 Gy, 5 Gy and 7.5 Gy, respectively. The regeneration endpoints, including liver index (LI); mitotic index (MI); liver proliferation index (LPI); proliferating cell nuclear antigen-labeling index (PCNA-LI); serum hepatic growth factor (HGF), vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-α and interleukin (IL)-6, were evaluated on 0 day, 30-day, 60-day, 90-day, 120-day and 150-day after IR. Serum and in situ TGF-β1 were also measured. In both experimental groups, the IR injuries were sublethal, inducing no more than 9% animal deaths. Upon TAA withdrawal, hepatic regeneration decelerated in the controls. In Experiment 1 except for LI, all other regeneration parameters were significantly higher than those in controls for both right-half and left-half livers. In Experiment 2 all regeneration parameters were also higher compared with those in controls for both half livers. Serum HGF and VEGF were increased compared with that of controls. Both unirradiated and low dose-irradiated cirrhotic liver were able to regenerate triggered by sublethal partial liver IR and higher doses and IR to both halves liver triggered a more enhanced regeneration. (author)

Cytokines and Liver Diseases

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Herbert Tilg

2001-01-01

Full Text Available Cytokines are pleiotropic peptides produced by virtually every nucleated cell in the body. In most tissues, including the liver, constitutive production of cytokines is absent or minimal. There is increasing evidence that several cytokines mediate hepatic inflammation, apoptosis and necrosis of liver cells, cholestasis and fibrosis. Interestingly, the same mediators also mediate the regeneration of liver tissue after injury. Among the various cytokines, the proinflammatory cytokine tumour necrosis factor-alpha (TNF-a has emerged as a key factor in various aspects of liver disease, such as cachexia and/or cholestasis. Thus, antagonism of TNF-a and other injury-related cytokines in liver diseases merits evaluation as a treatment of these diseases. However, because the same cytokines are also necessary for the regeneration of the tissue after the liver has been injured, inhibition of these mediators might impair hepatic recovery. The near future will bring the exiting clinical challenge of testing new anticytokine strategies in various liver diseases.

Review fantastic medical implications of 3D-printing in liver surgeries, liver regeneration, liver transplantation and drug hepatotoxicity testing: A review.

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Wang, Jing-Zhang; Xiong, Nan-Yan; Zhao, Li-Zhen; Hu, Jin-Tian; Kong, De-Cheng; Yuan, Jiang-Yong

2018-06-07

The epidemiological trend in liver diseases becomes more serious worldwide. Several recent articles published by International Journal of Surgery in 2018 particularly emphasized the encouraging clinical benefits of hepatectomy, liver regeneration and liver transplantation, however, there are still many technical bottlenecks underlying these therapeutic approaches. Remarkably, a few preliminary studies have shown some clues to the role of three-dimensional (3D) printing in improving traditional therapy for liver diseases. Here, we concisely elucidated the curative applications of 3D-printing (no cells) and 3D Bio-printing (with hepatic cells), such as 3D-printed patient-specific liver models and devices for medical education, surgical simulation, hepatectomy and liver transplantation, 3D Bio-printed hepatic constructs for liver regeneration and artificial liver, 3D-printed liver tissues for evaluating drug's hepatotoxicity, and so on. Briefly, 3D-printed liver models and bioactive tissues may facilitate a lot of key steps to cure liver disorders, predictably bringing promising clinical benefits. This work further provides novel insights into facilitating treatment of hepatic carcinoma, promoting liver regeneration both in vivo and in vitro, expanding transplantable liver resources, maximizing therapeutic efficacy as well as minimizing surgical complications, medical hepatotoxicity, operational time, economic costs, etc. Copyright © 2018. Published by Elsevier Ltd.

The nuclear pore density in rat liver cells upon regeneration and total body X-ray irradiation

International Nuclear Information System (INIS)

Kuz'mina, S.N.; Troitskaya, L.P.; Mirkhamidova, P.A.; Bul'dyaeva, T.V.; Zbarskij, I.B.; Grigor'ev, V.B.; Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Virusologii)

1979-01-01

The nuclear pore density has been investigated in rat liver cells in the course of regeneration and X-ray irradiation. It has been found that the number of pore complexes (PC) per nuclear shell (NS) unit area in the liver cells is not constant. In an hour following whole-body irradiation of rats with a regenerating liver at the 1200 R dose the number of PC per 1 μm 2 of the nuclear shell area decreases by 5, 8 times as compared with the PC density in the regenerating liver cells of the irradiated rats, the PC degradation and structural rupture being observed. It has been established by means of the freezing-etching method which enables PC surfaces observation as for cytoplasma as well as for nucleoplasma that the PC peripheral granulas and the central granula consist of subparticles being approximately of the same size. The central granula forms a channel through which the material containing RNA passes from the nucleus to the cytoplasma. On the basis of the fact that the treatement by Triton X-100, disarranging the integrity of the NS membranous structure, preserves PC in relation to the fibrous layer as well as on the basis of the unequal nuclear pore state observed on the platinum-carbon replicas from nuclei splits it is supposed that PC can be formed in the nucleus and then in the course of repening ''built in'' PS

Epidermal growth factor receptor restoration rescues the fatty liver regeneration in mice.

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Zimmers, Teresa A; Jin, Xiaoling; Zhang, Zongxiu; Jiang, Yanlin; Koniaris, Leonidas G

2017-10-01

Hepatic steatosis is a common histological finding in obese patients. Even mild steatosis is associated with delayed hepatic regeneration and poor outcomes following liver resection or transplantation. We sought to identify and target molecular pathways that mediate this dysfunction. Lean mice and mice made obese through feeding of a high-fat, hypercaloric diet underwent 70 or 80% hepatectomy. After 70% resection, obese mice demonstrated 100% survival but experienced increased liver injury, reduced energy stores, reduced mitoses, increased necroapoptosis, and delayed recovery of liver mass. Increasing liver resection to 80% was associated with mortality of 40% in lean and 80% in obese mice ( P steatosis might promote liver regeneration and survival following hepatic resection or transplantation. Copyright © 2017 the American Physiological Society.

Enhancement of liver regeneration and liver surgery

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Olthof, P.B.

2017-01-01

Liver regeneration allows surgical resection of up to 75% of the liver and enables curative treatment potential for patients with primary or secondary hepatic malignancies. Liver surgery is associated with substantial risks, reflected by considerable morbidity and mortality rates. Optimization of

Thrombospondin-1 is a novel negative regulator of liver regeneration after partial hepatectomy through transforming growth factor-beta1 activation in mice.

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Hayashi, Hiromitsu; Sakai, Keiko; Baba, Hideo; Sakai, Takao

2012-05-01

The matricellular protein, thrombospondin-1 (TSP-1), is prominently expressed during tissue repair. TSP-1 binds to matrix components, proteases, cytokines, and growth factors and activates intracellular signals through its multiple domains. TSP-1 converts latent transforming growth factor-beta1 (TGF-β1) complexes into their biologically active form. TGF-β plays significant roles in cell-cycle regulation, modulation of differentiation, and induction of apoptosis. Although TGF-β1 is a major inhibitor of proliferation in cultured hepatocytes, the functional requirement of TGF-β1 during liver regeneration remains to be defined in vivo. We generated a TSP-1-deficient mouse model of a partial hepatectomy (PH) and explored TSP-1 induction, progression of liver regeneration, and TGF-β-mediated signaling during the repair process after hepatectomy. We show here that TSP-1-mediated TGF-β1 activation plays an important role in suppressing hepatocyte proliferation. TSP-1 expression was induced in endothelial cells (ECs) as an immediate early gene in response to PH. TSP-1 deficiency resulted in significantly reduced TGF-β/Smad signaling and accelerated hepatocyte proliferation through down-regulation of p21 protein expression. TSP-1 induced in ECs by reactive oxygen species (ROS) modulated TGF-β/Smad signaling and proliferation in hepatocytes in vitro, suggesting that the immediately and transiently produced ROS in the regenerating liver were the responsible factor for TSP-1 induction. We have identified TSP-1 as an inhibitory element in regulating liver regeneration by TGF-β1 activation. Our work defines TSP-1 as a novel immediate early gene that could be a potential therapeutic target to accelerate liver regeneration. Copyright © 2011 American Association for the Study of Liver Diseases.

The Role of Innate Lymphoid Cells in Immune-Mediated Liver Diseases

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Liu, Meifang; Zhang, Cai

2017-01-01

Innate lymphoid cells (ILCs) are a recently identified group of innate immune cells lacking antigen-specific receptors that can mediate immune responses and regulate tissue homeostasis and inflammation. ILCs comprise group 1 ILCs, group 2 ILCs, and group 3 ILCs. These ILCs usually localize at mucosal surfaces and combat pathogens by the rapid release of certain cytokines. However, the uncontrolled activation of ILCs can also lead to damaging inflammation, especially in the gut, lung, and skin. Although the physiological and pathogenic roles of ILCs in liver diseases have been attracting increasing attention recently, there has been no systematic review regarding the roles of ILCs in immune-mediated liver diseases. Here, we review the relationships between the ILC subsets and their functions in immune-mediated liver diseases, and discuss their therapeutic potential based on current knowledge about the functional roles of these cells in liver diseases. PMID:28659927

Mechanism of impaired regeneration of fatty liver in mouse partial hepatectomy model.

Science.gov (United States)

Murata, Hiroshi; Yagi, Takahito; Iwagaki, Hiromi; Ogino, Tetsuya; Sadamori, Hiroshi; Matsukawa, Hiroyoshi; Umeda, Yuzoh; Haga, Sanae; Takaka, Noriaki; Ozaki, Michitaka

2007-12-01

The mechanism of injury in steatotic liver under pathological conditions been extensively examined. However, the mechanism of an impaired regeneration is still not well understood. The aim of this study was to analyze the mechanism of impaired regeneration of steatotic liver after partial hepatectomy (PH). db/db fatty mice and lean littermates were used for the experiments. Following 70% PH, the survival rate and recovery of liver mass were examined. Liver tissue was histologically examined and analyzed by western blotting and RT-PCR. Of 35 db/db mice, 25 died within 48 h of PH, while all of the control mice survived. Liver regeneration of surviving db/db mice was largely impaired. In db/db mice, mitosis of hepatocytes after PH was disturbed, even though proliferating cell nuclear antigen (PCNA) expression (G1 to S phase marker) in hepatocytes was equally observed in both mice groups. Interestingly, phosphorylation of Cdc2 in db/db mice was suppressed by reduced expression of Wee1 and Myt1, which phosphorylate Cdc2 in S to G2 phase. In steatotic liver, cell-cycle-related proliferative disorders occurred at mid-S phase after PCNA expression. Reduced expression of Wee1 and Myt1 kinases may therefore maintain Cdc2 in an unphosphorylated state and block cell cycle progression in mid-S phase. These kinases may be critical factors involved in the impaired liver regeneration in fatty liver.

Liver regeneration and restoration of liver function after partial hepatectomy in patients with liver tumors

NARCIS (Netherlands)

Jansen, P. L.; Chamuleau, R. A.; van Leeuwen, D. J.; Schipper, H. G.; Busemann-Sokole, E.; van der Heyde, M. N.

1990-01-01

Liver regeneration and restoration of liver function were studied in six patients who underwent partial hepatectomy with removal of 30-70% of the liver. Liver volume and liver regeneration were studied by single-photon computed tomography (SPECT), using 99mTc-colloid as tracer. The method was

Putrescine treatment reverses α-tocopherol-induced desynchronization of polyamine and retinoid metabolism during rat liver regeneration

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Lourdes Sánchez-Sevilla

2016-10-01

Full Text Available Abstract Background The pre-treatment with α-tocopherol inhibits progression of rat liver proliferation induced by partial hepatectomy (PH, by decreasing and/or desynchronizing cyclin D1 expression and activation into the nucleus, activation and nuclear translocation of STAT-1 and -3 proteins and altering retinoid metabolism. Interactions between retinoic acid and polyamines have been reported in the PH-induced rat liver regeneration. Therefore, we evaluated the effect of low dosage of α-tocopherol on PH-induced changes in polyamine metabolism. Methods This study evaluated the participation of polyamine synthesis and metabolism during α-tocopherol-induced inhibition of rat liver regeneration. In PH-rats (Wistar treated with α-tocopherol and putrescine, parameters indicative of cell proliferation, lipid peroxidation, ornithine decarboxylase expression (ODC, and polyamine levels, were determined. Results Pre-treatment with α-tocopherol to PH-animals exerted an antioxidant effect, shifting earlier the increased ODC activity and expression, temporally affecting polyamine synthesis and ornithine metabolism. Whereas administration of putrescine induced minor changes in PH-rats, the concomitant treatment actually counteracted most of adverse actions exerted by α-tocopherol on the remnant liver, restituting its proliferative potential, without changing its antioxidant effect. Putrescine administration to these rats was also associated with lower ODC expression and activity in the proliferating liver, but the temporally shifting in the amount of liver polyamines induced by α-tocopherol, was also “synchronized” by the putrescine administration. The latter is supported by the fact that a close relationship was observed between fluctuations of polyamines and retinoids. Conclusions Putrescine counteracted most adverse actions exerted by α-tocopherol on rat liver regeneration, restoring liver proliferative potential and restituting the decreased

Liver regeneration and restoration of liver function after partial hepatectomy in patients with liver tumors

International Nuclear Information System (INIS)

Jansen, P.L.M.; Chamuleau, R.A.F.; Leeuwen, D.J. van; Schippor, H.G.; Busemann-Sokole, E.; Heyde, M.N. van der

1990-01-01

Liver regeneration and restoration of liver function were studied in six patients who underwent partial hepatectomy with removal of 30-70% of the liver. Liver volume and liver regeneration were studied by single photon computed tomography (SPECT), using 99m Tc-colloid as tracer. The method was assessed in 11 patients by comparing the pre- and post-operative volume measurement with the volume of the resected liver mass. Liver function was determined by measuring the galactose elimination capacity and the caffeine clearance. After a postoperative follow-up period of 50 days, the liver had regenerated maximally to a volume of 75 ± 2% of the preoperative liver mass. Maximal restoration of liver function was achieved 120 days after operation and amounted to 75 ± 10% for the caffeine clearance and to 100 ± 25% for the galactose elimination capacity. This study shows that SPECT is a useful method for assessing liver regeneration in patients after partial hepatectomy. The study furthermore shows that caffeine clearance correlates well with total liver volume, whereas the galactose elimination capacity overestimates total liver volume after partial hepatectomy. 22 refs

The combined effect of erythropoietin and granulocyte macrophage colony stimulating factor on liver regeneration after major hepatectomy in rats

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Frangou Matrona

2010-07-01

Full Text Available Abstract Background The liver presents a remarkable capacity for regeneration after hepatectomy but the exact mechanisms and mediators involved are not yet fully clarified. Erythropoietin (EPO and Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF have been shown to promote liver regeneration after major hepatectomy. Aim of this experimental study is to compare the impact of exogenous administration of EPO, GM-CSF, as well as their combination on the promotion of liver regeneration after major hepatectomy. Methods Wistar rats were submitted to 70% major hepatectomy. The animals were assigned to 4 experimental groups: a control group (n = 21 that received normal saline, an EPO group (n = 21, that received EPO 500 IU/kg, a GM-CSF group (n = 21 that received 20 mcg/kg of GM-CSF and a EPO+GMCSF group (n = 21 which received a combination of the above. Seven animals of each group were killed on the 1st, 3rd and 7th postoperative day and their remnant liver was removed to evaluate liver regeneration by immunochemistry for PCNA and Ki 67. Results Our data suggest that EPO and GM-CSF increases liver regeneration following major hepatectomy when administered perioperatively. EPO has a more significant effect than GM-CSF (p Conclusion EPO, GM-CSF and their combination enhance liver regeneration after hepatectomy in rats when administered perioperatively. However their combination has a weaker effect on liver regeneration compared to EPO alone. Further investigation is needed to assess the exact mechanisms that mediate this finding.

Sirolimus influence on hepatectomy-induced liver regeneration in rats

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Edimar Leandro Toderke

Full Text Available OBJECTIVE: To evaluate the influence of sirolimus on liver regeneration triggered by resection of 70% of the liver of adult rats. METHODS: we used 40 Wistar rats randomly divided into two groups (study and control, each group was divided into two equal subgroups according to the day of death (24 hours and seven days. Sirolimus was administered at a dose of 1mg/kg in the study group and the control group was given 1 ml of saline. The solutions were administered daily since three days before hepatectomy till the rats death to removal of the regenerated liver, conducted in 24 hours or 7 days after hepatectomy. Liver regeneration was measured by the KWON formula, by thenumber of mitotic figures (hematoxylin-eosin staining and by the immunohistochemical markers PCNA and Ki-67. RESULTS: there was a statistically significant difference between the 24h and the 7d groups. When comparing the study and control groups in the same period, there was a statistically significant variation only for Ki-67, in which there were increased numbers of hepatocytes in cell multiplication in the 7d study group compared with the 7d control group (p = 0.04. CONCLUSION: there was no negative influence of sirolimus in liver regeneration and there was a positive partial effect at immunohistochemistry with Ki-67.

Impact of future remnant liver volume on post-hepatectomy regeneration in non-cirrhotic livers

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Duilio ePagano

2014-04-01

Full Text Available Objective: The purpose of the study is to detect if some parameters can be considered as predictors of liver regeneration in two different patient populations composed of in living donors for adult to adult living donor liver transplant and patients with hepatic malignancies within a single institution.Summary Background Data: Preoperative multi-detector computed tomography volumetry is an essential tool to assess the volume of the remnant liver. Methods: a retrospective analysis from an ongoing clinical study on 100 liver resections, between 2004 and 2010. 70 patients were right lobe living donors for liver transplantation and 30 patients were resected for treatment of tumors. Pre-surgical factors such as age, weight, height, body mass index (BMI, original liver volume, future remnant liver volume (FRLV, spleen volume, liver function tests, creatinine, platelet count, steatosis, portal vein embolization (PVE and number of resected segments were analyzed to evidence potential markers for liver regeneration. Results: Follow-up period did not influence the amount of liver regenerated: the linear regression evidenced that there is no correlation between percentage of liver regeneration and time of follow-up (p=0.88. The pre-surgical variables that resulted markers of liver regeneration include higher preoperative values of BMI (p=0.01, bilirubin(p=0.04, glucose (p=0.05 and GGT (p=0.014; the most important association was revealed regarding the lower FRLV (pConclusions: Liver regeneration follows similar pathway in living donor and in patients resected for cancer. Small FRLV tends to regenerate more and faster, confirming that a larger resections may lead to a greater promotion of liver regeneration in patients with optimal conditions in terms of body habitus, preoperative liver function tests and glucose level.

Liver regeneration signature in hepatitis B virus (HBV-associated acute liver failure identified by gene expression profiling.

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Oriel Nissim

Full Text Available The liver has inherent regenerative capacity via mitotic division of mature hepatocytes or, when the hepatic loss is massive or hepatocyte proliferation is impaired, through activation of hepatic stem/progenitor cells (HSPC. The dramatic clinical course of acute liver failure (ALF has posed major limitations to investigating the molecular mechanisms of liver regeneration and the role of HSPC in this setting. We investigated the molecular mechanisms of liver regeneration in 4 patients who underwent liver transplantation for hepatitis B virus (HBV-associated ALF.Gene expression profiling of 17 liver specimens from the 4 ALF cases and individual specimens from 10 liver donors documented a distinct gene signature for ALF. However, unsupervised multidimensional scaling and hierarchical clustering identified two clusters of ALF that segregated according to histopathological severity massive hepatic necrosis (MHN; 2 patients and submassive hepatic necrosis (SHN; 2 patients. We found that ALF is characterized by a strong HSPC gene signature, along with ductular reaction, both of which are more prominent in MHN. Interestingly, no evidence of further lineage differentiation was seen in MHN, whereas in SHN we detected cells with hepatocyte-like morphology. Strikingly, ALF was associated with a strong tumorigenesis gene signature. MHN had the greatest upregulation of stem cell genes (EpCAM, CK19, CK7, whereas the most up-regulated genes in SHN were related to cellular growth and proliferation. The extent of liver necrosis correlated with an overriding fibrogenesis gene signature, reflecting the wound-healing process.Our data provide evidence for a distinct gene signature in HBV-associated ALF whose intensity is directly correlated with the histopathological severity. HSPC activation and fibrogenesis positively correlated with the extent of liver necrosis. Moreover, we detected a tumorigenesis gene signature in ALF, emphasizing the close relationship between

Hepatocyte-specific deletion of Cdc42 results in delayed liver regeneration after partial hepatectomy in mice

DEFF Research Database (Denmark)

Yuan, Haixin; Zhang, Hong; Wu, Xunwei

2009-01-01

Cdc42, a member of the Rho guanosine triphosphatase (GTPase) family, plays important roles in the regulation of the cytoskeleton, cell proliferation, cell polarity, and cellular transport, but little is known about its specific function in mammalian liver. We investigated the function of Cdc42...... in regulating liver regeneration. Using a mouse model with liver-specific knockout of Cdc42 (Cdc42LK), we studied liver regeneration after partial hepatectomy. Histological analysis, immunostaining, and western blot analysis were performed to characterize Cdc42LK livers and to explore the role of Cdc42 in liver...... regeneration. In control mouse livers, Cdc42 became activated between 3 and 24 hours after partial hepatectomy. Loss of Cdc42 led to a significant delay of liver recovery after partial hepatectomy, which was associated with reduced and delayed DNA synthesis indicated by 5-bromo-2'-deoxyuridine staining...

Mitochondrial DNA Unwinding Enzyme Required for Liver Regeneration | Center for Cancer Research

Science.gov (United States)

The liver has an exceptional capacity to proliferate. This ability allows the liver to regenerate its mass after partial surgical removal or injury and is the key to successful partial liver transplants. Liver cells, called hepatocytes, are packed with mitochondria, and regulating mitochondrial DNA (mtDNA) copy number is crucial to mitochondrial function, including energy production, during proliferation. Yves Pommier, M.D., Ph.D., of CCR’s Developmental Therapeutics Branch, and his colleagues recently showed that the vertebrate mitochondrial topoisomerase, Top1mt, was critical in maintaining mitochondrial function in the heart after doxorubicin-induced damage. The group wondered whether Top1mt might play a similar role in liver regeneration.

Effect of the Human Amniotic Membrane on Liver Regeneration in Rats

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Mesut Sipahi

2015-01-01

Full Text Available Introduction. Operations are performed for broader liver surgery indications for a better understanding of hepatic anatomy/physiology and developments in operation technology. Surgery can cure some patients with liver metastasis of some tumors. Nevertheless, postoperative liver failure is the most feared complication causing mortality in patients who have undergone excision of a large liver mass. The human amniotic membrane has regenerative effects. Thus, we investigated the effects of the human amniotic membrane on regeneration of the resected liver. Methods. Twenty female Wistar albino rats were divided into control and experimental groups and underwent a 70% hepatectomy. The human amniotic membrane was placed over the residual liver in the experimental group. Relative liver weight, histopathological features, and biochemical parameters were assessed on postoperative day 3. Results. Total protein and albumin levels were significantly lower in the experimental group than in the control group. No difference in relative liver weight was observed between the groups. Hepatocyte mitotic count was significantly higher in the experimental group than in the control group. Hepatic steatosis was detected in the experimental group. Conclusion. Applying the amniotic membrane to residual liver adversely affected liver regeneration. However, mesenchymal stem cell research has the potential to accelerate liver regeneration investigations.

Fcγ receptor-mediated inflammation inhibits axon regeneration.

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Gang Zhang

Full Text Available Anti-glycan/ganglioside antibodies are the most common immune effectors found in patients with Guillain-Barré Syndrome, which is a peripheral autoimmune neuropathy. We previously reported that disease-relevant anti-glycan autoantibodies inhibited axon regeneration, which echo the clinical association of these antibodies and poor recovery in Guillain-Barré Syndrome. However, the specific molecular and cellular elements involved in this antibody-mediated inhibition of axon regeneration are not previously defined. This study examined the role of Fcγ receptors and macrophages in the antibody-mediated inhibition of axon regeneration. A well characterized antibody passive transfer sciatic nerve crush and transplant models were used to study the anti-ganglioside antibody-mediated inhibition of axon regeneration in wild type and various mutant and transgenic mice with altered expression of specific Fcγ receptors and macrophage/microglia populations. Outcome measures included behavior, electrophysiology, morphometry, immunocytochemistry, quantitative real-time PCR, and western blotting. We demonstrate that the presence of autoantibodies, directed against neuronal/axonal cell surface gangliosides, in the injured mammalian peripheral nerves switch the proregenerative inflammatory environment to growth inhibitory milieu by engaging specific activating Fcγ receptors on recruited monocyte-derived macrophages to cause severe inhibition of axon regeneration. Our data demonstrate that the antibody orchestrated Fcγ receptor-mediated switch in inflammation is one mechanism underlying inhibition of axon regeneration. These findings have clinical implications for nerve repair and recovery in antibody-mediated immune neuropathies. Our results add to the complexity of axon regeneration in injured peripheral and central nervous systems as adverse effects of B cells and autoantibodies on neural injury and repair are increasingly recognized.

Anti-inflammatory liposomes have no impact on liver regeneration in rats

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Betina Norman Jepsen

2015-12-01

Conclusion: Low dose dexamethasone targeted to Kupffer cells does not affect histological liver cell regeneration after 70% hepatectomy in rats, but reduces the inflammatory response judged by circulating markers of inflammation.

Regeneration of the liver at different periods of mononuclear infiltration induced by zymosan granules

International Nuclear Information System (INIS)

Shcherbakov, V.I.; Komlyagina, T.G.; Mayanskii, D.N.

1985-01-01

The aim of this investigation was to discover how the liver,with areas of mononuclear infiltration, developing in response to activation of Kupffer cells (KC) by zymosan granules (ZG), regenerates. In the experiments, an intraperitoneal injection of 1 microCi of 3 H-thymidine/g body weight was given to the mice 1 h before sacrifice. Proliferation of hepatocytes and regeneration of the liver were intensified most when partial resection of the liver (PRL) was performed at the peak of mononuclear infiltration of the liver, namely five days after injection of ZG. The data indicate that not only activated KC, but also areas of mononuclear infiltration potentiate hepatocyte regeneration

DNA alkylation and tumor induction in regenerating rat liver after cell cycle-related continuous N-nitrosodimethylamine infusion

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Rabes, H.M.; Kerler, R.; Wilhelm, R.

1983-01-01

Synchronized regenerating rat liver after partial hepatectomy was used to study cell cycle-related DNA base alkylation and liver carcinogenesis. A continuous iv infusion of (/sup 14/C)N-nitrosodimethylamine (DMN) at a dose of 0.5 mg/kg/hour was given to inbred male Wistar Af/Han rats over a period of 8 hours either during the G1 phase, hydroxyurea-synchronized DNA synthesis, or the G2+M-phase of regenerating liver or to untreated rats (G0-phase liver--carcinogen dose, 1.5 mg/kg/hour). Two hours after the end of the infusion, the amount of 7-methylguanine was highest in the G0-phase liver, with a decrease in the G1 phase, the S-phase, and the G2+M-phase. After continuous DMN exposure, the O/sub 6/-methylguanine:7-methylguanine ratio was lower in the S-phase and G2+M-phase livers than in the G0-phase and G1-phase livers, indicating an increased O/sub 6/-methylguanine repair during DNA synthesis and the G2+M-phase. Liver tumors in rats treated by continuous DMN infusion either during the G0 phase or the S-phase developed only after carcinogen exposure during DNA synthesis.

Interleukin 17-producing γδT cells promote hepatic regeneration in mice.

Science.gov (United States)

Rao, Raghavendra; Graffeo, Christopher S; Gulati, Rishabh; Jamal, Mohsin; Narayan, Suchithra; Zambirinis, Constantinos P; Barilla, Rocky; Deutsch, Michael; Greco, Stephanie H; Ochi, Atsuo; Tomkötter, Lena; Blobstein, Reuven; Avanzi, Antonina; Tippens, Daniel M; Gelbstein, Yisroel; Van Heerden, Eliza; Miller, George

2014-08-01

Subsets of leukocytes synergize with regenerative growth factors to promote hepatic regeneration. γδT cells are early responders to inflammation-induced injury in a number of contexts. We investigated the role of γδT cells in hepatic regeneration using mice with disruptions in Tcrd (encodes the T-cell receptor δ chain) and Clec7a (encodes C-type lectin domain family 7 member a, also known as DECTIN1). We performed partial hepatectomies on wild-type C57BL/6, CD45.1, Tcrd(-/-), or Clec7a(-/-) mice. Cells were isolated from livers of patients and mice via mechanical and enzymatic digestion. γδT cells were purified by fluorescence-activated cell sorting. In mice, partial hepatectomy up-regulated expression of CCL20 and ligands of Dectin-1, which was associated with recruitment and activation of γδT cells and their increased production of interleukin (IL)-17 family cytokines. Recruited γδT cells induced production of IL-6 by antigen-presenting cells and suppressed expression of interferon gamma by natural killer T cells, promoting hepatocyte proliferation. Absence of IL-17-producing γδT cells or deletion of Dectin-1 prevented development of regenerative phenotypes in subsets of innate immune cells. This slowed liver regeneration and was associated with reduced expression of regenerative growth factors and cell cycle regulators. Conversely, exogenous administration of IL-17 family cytokines or Dectin-1 ligands promoted regeneration. More broadly, we found that γδT cells are required for inflammatory responses mediated by IL-17 and Dectin-1. γδT cells regulate hepatic regeneration by producing IL-22 and IL-17, which have direct mitogenic effects on hepatocytes and promote a regenerative phenotype in hepatic leukocytes, respectively. Dectin-1 ligation is required for γδT cells to promote hepatic regeneration. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

Human Adipose Tissue Derived Stem Cells Promote Liver Regeneration in a Rat Model of Toxic Injury

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Eva Koellensperger

2013-01-01

Full Text Available In the light of the persisting lack of donor organs and the risks of allotransplantations, the possibility of liver regeneration with autologous stem cells from adipose tissue (ADSC is an intriguing alternative. Using a model of a toxic liver damage in Sprague Dawley rats, generated by repetitive intraperitoneal application of retrorsine and allyl alcohol, the ability of human ADSC to support the restoration of liver function was investigated. A two-thirds hepatectomy was performed, and human ADSC were injected into one remaining liver lobe in group 1 (n = 20. Injection of cell culture medium performed in group 2 (n = 20 served as control. Cyclosporine was applied to achieve immunotolerance. Blood samples were drawn weekly after surgery to determine liver-correlated blood values. Six and twelve weeks after surgery, animals were sacrificed and histological sections were analyzed. ADSC significantly raised postoperative albumin (P < 0.017, total protein (P < 0.031, glutamic oxaloacetic transaminase (P < 0.001, and lactate dehydrogenase (P < 0.04 levels compared to injection of cell culture medium alone. Transplanted cells could be found up to twelve weeks after surgery in histological sections. This study points towards ADSC being a promising alternative to hepatocyte or liver organ transplantation in patients with severe liver failure.

Chronological protein synthesis in regenerating rat liver.

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He, Jinjun; Hao, Shuai; Zhang, Hao; Guo, Fuzheng; Huang, Lingyun; Xiao, Xueyuan; He, Dacheng

2015-07-01

Liver regeneration has been studied for decades; however, its regulation remains unclear. In this study, we report a dynamic tracing of protein synthesis in rat regenerating liver with a new proteomic technique, (35) S in vivo labeling analysis for dynamic proteomics (SiLAD). Conventional proteomic techniques typically measure protein alteration in accumulated amounts. The SiLAD technique specifically detects protein synthesis velocity instead of accumulated amounts of protein through (35) S pulse labeling of newly synthesized proteins, providing a direct way for analyzing protein synthesis variations. Consequently, protein synthesis within short as 30 min was visualized and protein regulations in the first 8 h of regenerating liver were dynamically traced. Further, the 3.5-5 h post partial hepatectomy (PHx) was shown to be an important regulatory turning point by acute regulation of many proteins in the initiation of liver regeneration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Immune mediated liver failure.

Science.gov (United States)

Wang, Xiaojing; Ning, Qin

2014-01-01

Liver failure is a clinical syndrome of various etiologies, manifesting as jaundice, encephalopathy, coagulopathy and circulatory dysfunction, which result in subsequent multiorgan failure. Clinically, liver failure is classified into four categories: acute, subacute, acute-on-chronic and chronic liver failure. Massive hepatocyte death is considered to be the core event in the development of liver failure, which occurs when the extent of hepatocyte death is beyond the liver regenerative capacity. Direct damage and immune-mediated liver injury are two major factors involved in this process. Increasing evidence has suggested the essential role of immune-mediated liver injury in the pathogenesis of liver failure. Here, we review the evolved concepts concerning the mechanisms of immune-mediated liver injury in liver failure from human and animal studies. Both innate and adaptive immunity, especially the interaction of various immune cells and molecules as well as death receptor signaling system are discussed. In addition, we highlight the concept of "immune coagulation", which has been shown to be related to the disease progression and liver injury exacerbation in HBV related acute-on-chronic liver failure.

Augmenter of liver regeneration (ALR) protects human hepatocytes against apoptosis

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Ilowski, Maren [Liver Regeneration Group, Department of Surgery, Grosshadern Hospital, Ludwig Maximilians University, Munich (Germany); Kleespies, Axel [Department of Surgery, Grosshadern Hospital, Ludwig Maximilians University, Munich (Germany); Toni, Enrico N. de [Department of Medicine II, Grosshadern Hospital, Ludwig Maximilians University, Munich (Germany); Donabauer, Barbara [Liver Regeneration Group, Department of Surgery, Grosshadern Hospital, Ludwig Maximilians University, Munich (Germany); Jauch, Karl-Walter [Department of Surgery, Grosshadern Hospital, Ludwig Maximilians University, Munich (Germany); Hengstler, Jan G. [Leibniz Research Centre for Working Environment and Human Factors, Technical University, Dortmund (Germany); Thasler, Wolfgang E., E-mail: wolfgang.thasler@med.uni-muenchen.de [Liver Regeneration Group, Department of Surgery, Grosshadern Hospital, Ludwig Maximilians University, Munich (Germany); Department of Surgery, Grosshadern Hospital, Ludwig Maximilians University, Munich (Germany)

2011-01-07

Research highlights: {yields} ALR decreases cytochrome c release from mitochondria. {yields} ALR protects hepatocytes against apoptosis induction by ethanol, TRAIL, anti-Apo, TGF-{beta} and actinomycin D. {yields} ALR exerts a liver-specific anti-apoptotic effect. {yields} A possible medical usage of ALR regarding protection of liver cells during apoptosis inducing therapies. -- Abstract: Augmenter of liver regeneration (ALR) is known to support liver regeneration and to stimulate proliferation of hepatocytes. However, it is not known if ALR exerts anti-apoptotic effects in human hepatocytes and whether this protective effect is cell type specific. This is relevant, because compounds that protect the liver against apoptosis without undesired effects, such as protection of metastatic tumour cells, would be appreciated in several clinical settings. Primary human hepatocytes (phH) and organotypic cancer cell lines were exposed to different concentrations of apoptosis inducers (ethanol, TRAIL, anti-Apo, TGF-{beta}, actinomycin D) and cultured with or without recombinant human ALR (rhALR). Apoptosis was evaluated by the release of cytochrome c from mitochondria and by FACS with propidium iodide (PI) staining. ALR significantly decreased apoptosis induced by ethanol, TRAIL, anti-Apo, TGF-{beta} and actinomycin D. Further, the anti-apoptotic effect of ALR was observed in primary human hepatocytes and in HepG2 cells but not in bronchial (BC1), colonic (SW480), gastric (GC1) and pancreatic (L3.6PL) cell lines. Therefore, the hepatotrophic growth factor ALR acts in a liver specific manner with regards to both its mitogenic and its anti-apoptotic effect. Unlike the growth factors HGF and EGF, rhALR acts in a liver specific manner. Therefore, ALR is a promising candidate for further evaluation as a possible hepatoprotective factor in clinical settings.

Augmenter of liver regeneration (ALR) protects human hepatocytes against apoptosis

International Nuclear Information System (INIS)

Ilowski, Maren; Kleespies, Axel; Toni, Enrico N. de; Donabauer, Barbara; Jauch, Karl-Walter; Hengstler, Jan G.; Thasler, Wolfgang E.

2011-01-01

Research highlights: → ALR decreases cytochrome c release from mitochondria. → ALR protects hepatocytes against apoptosis induction by ethanol, TRAIL, anti-Apo, TGF-β and actinomycin D. → ALR exerts a liver-specific anti-apoptotic effect. → A possible medical usage of ALR regarding protection of liver cells during apoptosis inducing therapies. -- Abstract: Augmenter of liver regeneration (ALR) is known to support liver regeneration and to stimulate proliferation of hepatocytes. However, it is not known if ALR exerts anti-apoptotic effects in human hepatocytes and whether this protective effect is cell type specific. This is relevant, because compounds that protect the liver against apoptosis without undesired effects, such as protection of metastatic tumour cells, would be appreciated in several clinical settings. Primary human hepatocytes (phH) and organotypic cancer cell lines were exposed to different concentrations of apoptosis inducers (ethanol, TRAIL, anti-Apo, TGF-β, actinomycin D) and cultured with or without recombinant human ALR (rhALR). Apoptosis was evaluated by the release of cytochrome c from mitochondria and by FACS with propidium iodide (PI) staining. ALR significantly decreased apoptosis induced by ethanol, TRAIL, anti-Apo, TGF-β and actinomycin D. Further, the anti-apoptotic effect of ALR was observed in primary human hepatocytes and in HepG2 cells but not in bronchial (BC1), colonic (SW480), gastric (GC1) and pancreatic (L3.6PL) cell lines. Therefore, the hepatotrophic growth factor ALR acts in a liver specific manner with regards to both its mitogenic and its anti-apoptotic effect. Unlike the growth factors HGF and EGF, rhALR acts in a liver specific manner. Therefore, ALR is a promising candidate for further evaluation as a possible hepatoprotective factor in clinical settings.

The regulation of cytoskeletal and liver-specific gene expression during liver regeneration and primary hepatocyte culture

International Nuclear Information System (INIS)

Robinson, G.S.

1989-01-01

The focus of this dissertation is to determine what role(s) the extracellular matrix and expression of certain cytoskeletal genes play in the regulation of hepatocyte growth and the maintenance of a differential state. The expression of several cytoskeletal and liver-specific genes was examined during liver regeneration and in hepatocyte cultures maintained in a hormonally-defined, serum-free medium and plated on two different matrices: rat tail collagen and the EHS matrix. During liver regeneration and in hepatocytes cultured on rat tail collagen, there was a dramatic increase in tubulin mRNA levels coincident with but not linked to DNA synthesis. The message levels for other cytoskeletal genes similarly increased, while a decrease was observed in the mRNA levels of the liver-specific genes, serum albumin and alpha 1 inhibitor III. Hepatocytes cultured on the EHS matrix resulted in the maintenance of low levels of cytoskeletal gene expression and high levels of liver-specific gene expression, similar to that observed in the normal liver. Results from subcellar fractionation and two-dimensional gel electrophoresis of 35 S-labelled proteins paralleled the results seen at the mRNA level. Preliminary work suggests that microtubule organization may play a role in the expression of the liver-specific genes which encode secreted proteins. These studies, which compare hepatocytes cultured on collagen or the EHS matrix gel, reveal that both cell-cell and cell-matrix interactions play a major role in the maintenance of the differential phenotype in hepatocytes

Proteome analysis of a hepatocyte-specific BIRC5 (survivin)-knockout mouse model during liver regeneration.

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Bracht, Thilo; Hagemann, Sascha; Loscha, Marius; Megger, Dominik A; Padden, Juliet; Eisenacher, Martin; Kuhlmann, Katja; Meyer, Helmut E; Baba, Hideo A; Sitek, Barbara

2014-06-06

The Baculoviral IAP repeat-containing protein 5 (BIRC5), also known as inhibitor of apoptosis protein survivin, is a member of the chromosomal passenger complex and a key player in mitosis. To investigate the function of BIRC5 in liver regeneration, we analyzed a hepatocyte-specific BIRC5-knockout mouse model using a quantitative label-free proteomics approach. Here, we present the analyses of the proteome changes in hepatocyte-specific BIRC5-knockout mice compared to wildtype mice, as well as proteome changes during liver regeneration induced by partial hepatectomy in wildtype mice and mice lacking hepatic BIRC5, respectively. The BIRC5-knockout mice showed an extensive overexpression of proteins related to cellular maintenance, organization and protein synthesis. Key regulators of cell growth, transcription and translation MTOR and STAT1/STAT2 were found to be overexpressed. During liver regeneration proteome changes representing a response to the mitotic stimulus were detected in wildtype mice. Mainly proteins corresponding to proliferation, cell cycle and cytokinesis were up-regulated. The hepatocyte-specific BIRC5-knockout mice showed impaired liver regeneration, which had severe consequences on the proteome level. However, several proteins with function in mitosis were found to be up-regulated upon the proliferative stimulus. Our results show that the E3 ubiquitin-protein ligase UHRF1 is strongly up-regulated during liver regeneration independently of BIRC5.

On the postradiation effect of cystamine in rat liver cells

International Nuclear Information System (INIS)

Gil'yano, N.Ya.; Malinovskij, O.V.

1979-01-01

The effect of cystamine, classical radioprotector introduced prior to and after irradiation has been tested. The protector has been paralelly tested on the regenerating liver in a presynthetic phase of a mitotic cycle (G 1 ). White nonbred male mice have been irradiated with 205 and 6O5 rad on the RUM-11 X-ray apparatus prior to (intact liver) and 6 hours after (regenerating liver) partial hepatectomy. Cystamine has been injected to animals 15 min prior to irradiation and in different periods after irradiation in the concentration of 150 mg/kg of weight. The decrease in the share of cells with asymmetic chromosome transformations (bridges and fragments in the anaphase) has been the protector effectiveness index. It is shown that the protector is effective in the cells of a regenerating liver only when introduced before irradiation, while in the cells of an intact liver it produces a protective effect both prior to and 15 mins after irradiation. Cystamine effectiveness for cells of the intact and regenerating liver has been investigated by introducing it after irradiation of animals with 250 and 305 rad. It has been established that the protector makes it possible to modify the irradiation effect within 20 mins after irradiation in the cells of the intact liver (Go). Cystamine postradiation protection in the cells of the regenerating liver (G 1 ) is low if it is introduced immediately after irradiation (1 min) and is absent after 10 min. The dependence of cystamine postradiation protective effect on the moment of liver cell stimulation has been investigated. It has been shown that the modification of irradiation effect is possible within 5 hrs after irradiation if the protector is introduced 15 min after irradiation of animals with 250 rad. The mechanism of the preparation action is discussed

Fasting enhances TRAIL-mediated liver natural killer cell activity via HSP70 upregulation.

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Vu T A Dang

Full Text Available Acute starvation, which is frequently observed in clinical practice, sometimes augments the cytolytic activity of natural killer cells against neoplastic cells. In this study, we investigated the molecular mechanisms underlying the enhancement of natural killer cell function by fasting in mice. The total number of liver resident natural killer cells in a unit weight of liver tissue obtained from C57BL/6J mice did not change after a 3-day fast, while the proportions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL+ and CD69+ natural killer cells were significantly elevated (n = 7, p <0.01, as determined by flow cytometric analysis. Furthermore, we found that TRAIL- natural killer cells that were adoptively transferred into Rag-2-/- γ chain-/- mice could convert into TRAIL+ natural killer cells in fasted mice at a higher proportion than in fed mice. Liver natural killer cells also showed high TRAIL-mediated antitumor function in response to 3-day fasting. Since these fasted mice highly expressed heat shock protein 70 (n = 7, p <0.05 in liver tissues, as determined by western blot, the role of this protein in natural killer cell activation was investigated. Treatment of liver lymphocytes with 50 µg/mL of recombinant heat shock protein 70 led to the upregulation of both TRAIL and CD69 in liver natural killer cells (n = 6, p <0.05. In addition, HSP70 neutralization by intraperitoneally injecting an anti- heat shock protein 70 monoclonal antibody into mice prior to fasting led to the downregulation of TRAIL expression (n = 6, p <0.05. These findings indicate that acute fasting enhances TRAIL-mediated liver natural killer cell activity against neoplastic cells through upregulation of heat shock protein 70.

Farnesoid X receptor, the bile acid sensing nuclear receptor, in liver regeneration

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Guodong Li

2015-03-01

Full Text Available The liver is unique in regenerative potential, which could recover the lost mass and function after injury from ischemia and resection. The underlying molecular mechanisms of liver regeneration have been extensively studied in the past using the partial hepatectomy (PH model in rodents, where 2/3 PH is carried out by removing two lobes. The whole process of liver regeneration is complicated, orchestrated event involving a network of connected interactions, which still remain fully elusive. Bile acids (BAs are ligands of farnesoid X receptor (FXR, a nuclear receptor of ligand-activated transcription factor. FXR has been shown to be highly involved in liver regeneration. BAs and FXR not only interact with each other but also regulate various downstream targets independently during liver regeneration. Moreover, recent findings suggest that tissue-specific FXR also contributes to liver regeneration significantly. These novel findings suggest that FXR has much broader role than regulating BA, cholesterol, lipid and glucose metabolism. Therefore, these researches highlight FXR as an important pharmaceutical target for potential use of FXR ligands to regulate liver regeneration in clinic. This review focuses on the roles of BAs and FXR in liver regeneration and the current underlying molecular mechanisms which contribute to liver regeneration.

New therapeutic strategies for canine liver disease; Growth factors and liver progenitor cells

NARCIS (Netherlands)

Arends, B.

2008-01-01

The liver has the unique capacity to regulate its mass after loss of functional liver cells due to liver disease, injury, and/or toxicity. Unfortunately, in the course of chronic liver disease this meticulously regulated regeneration process is imbalanced resulting in a decreased regenerative

SET mediates TCE-induced liver cell apoptosis through dephosphorylation and upregulation of nucleolin.

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Ren, Xiaohu; Huang, Xinfeng; Yang, Xifei; Liu, Yungang; Liu, Wei; Huang, Haiyan; Wu, Desheng; Zou, Fei; Liu, Jianjun

2017-06-20

Trichloroethylene (TCE) is an occupational and environmental chemical that can cause severe hepatotoxicity. While our previous studies showed that the phosphatase inhibitor SET is a key mediator of TCE-induced liver cell apoptosis, the molecular mechanisms remain elusive. Using quantitative phosphoproteomic analysis, we report here that nucleolin is a SET-regulated phosphoprotein in human liver HL-7702 cells. Functional analysis suggested that SET promoted dephosphorylation of nucleolin, decreased its binding to its transcriptional activator, c-myc, and upregulated nucleolin expression in TCE-treated cells. Importantly, TCE-induced hepatocyte apoptosis was significantly attenuated when nucleolin was downregulated with specific siRNAs. These findings indicate that TCE may induce hepatocyte apoptosis via SET-mediated dephosphorylation and overexpression of nucleolin.

Influence of epidermal growth factor on liver regeneration after partial hepatectomy in rats

DEFF Research Database (Denmark)

Olsen, Peter Skov; Boesby, S.; Kirkegaard, P.

2013-01-01

The role of epidermal growth factor on liver regeneration after partial hepatectomy in rats was investigated. After a 70% hepatectomy in rats, the concentration of epidermal growth factor in portal venous blood was unchanged compared with unoperated controls. However, small amounts of epidermal...... growth factor could be identified in portal venous blood after intestinal instillation of epidermal growth factor. Brunner's glands and the submandibular glands secrete epidermal growth factor. Extirpation of Brunner's glands decreased liver regeneration, whereas removal of the submandibular glands had...... no effect on liver regeneration. Epidermal growth factor antiserum reduced liver regeneration significantly. Oral or s.c. administration of epidermal growth factor had no effect on liver regeneration, whereas epidermal growth factor enhanced the effect of insulin and glucagon on liver regeneration...

Cutting Edge: Eosinophils Undergo Caspase-1-Mediated Pyroptosis in Response to Necrotic Liver Cells.

Science.gov (United States)

Palacios-Macapagal, Daphne; Connor, Jane; Mustelin, Tomas; Ramalingam, Thirumalai R; Wynn, Thomas A; Davidson, Todd S

2017-08-01

Many chronic liver disorders are characterized by dysregulated immune responses and hepatocyte death. We used an in vivo model to study the immune response to necrotic liver injury and found that necrotic liver cells induced eosinophil recruitment. Necrotic liver induced eosinophil IL-1β and IL-18 secretion, degranulation, and cell death. Caspase-1 inhibitors blocked all of these responses. Caspase-1-mediated cell death with accompanying cytokine release is the hallmark of a novel form of cell death termed pyroptosis. To confirm this response in a disease model, we isolated eosinophils from the livers of Schistosoma mansoni -infected mice. S. mansoni eggs lodge in the hepatic sinusoids of infected mice, resulting in hepatocyte death, inflammation, and progressive liver fibrosis. This response is typified by massive eosinophilia, and we were able to confirm pyroptosis in the infiltrating eosinophils. This demonstrated that pyroptosis is a cellular pathway used by eosinophils in response to large-scale hepatic cell death. Copyright © 2017 by The American Association of Immunologists, Inc.

Augmenter of liver regeneration causes different kinetics of ERK1/2 and Akt/PKB phosphorylation than EGF and induces hepatocyte proliferation in an EGF receptor independent and liver specific manner

Energy Technology Data Exchange (ETDEWEB)

Ilowski, Maren; Putz, Christine [Department of Surgery, Ludwig-Maximilians-University of Munich Hospital Grosshadern, Munich (Germany); Weiss, Thomas S. [Department of Surgery, University of Regensburg Hospital, Regensburg (Germany); Brand, Stephan [Department of Internal Medicine II, Ludwig-Maximilians-University of Munich Hospital Grosshadern, Munich (Germany); Jauch, Karl-Walter [Department of Surgery, Ludwig-Maximilians-University of Munich Hospital Grosshadern, Munich (Germany); Hengstler, Jan G. [Leibniz Research Centre for Working Environment and Human Factors, TU Dortmund University, Dortmund (Germany); Thasler, Wolfgang Erwin, E-mail: wolfgang.thasler@med.uni-muenchen.de [Department of Surgery, Ludwig-Maximilians-University of Munich Hospital Grosshadern, Munich (Germany)

2010-04-16

Background/Aim: Augmenter of liver regeneration (ALR) is a potent growth factor which supports liver regeneration in experimental animals. The aim of this study was to compare proliferation as well as the kinetics of ERK1/2 and Akt/PKB phosphorylation by recombinant human ALR (rhALR) and EGF in human hepatocytes and extrahepatic cells. Methods: Kinetics of ERK1/2 and Akt/PKB phosphorylation were determined in primary human hepatocytes (phh) after stimulation with rhALR and EGF. Induction of proliferation was analyzed in phh and several cell lines of hepatic and extrahepatic origin by the MTT and [{sup 3}H]-thymidine assay. Results: The kinetics of ERK phosphorylation showed clear differences, whereby rhALR caused a transient and EGF a permanent increase during the observation period of 60 min. For both, Akt and ERK phosphorylation, EGF caused a faster effect with maximal levels observed already after 2 min, whereas rhALR caused maximal phosphorylation between 10 and 15 min. Using the EGF receptor inhibitor AG1478 we provide evidence of an EGF receptor independent induction of proliferation by rhALR. Furthermore, rhALR induced proliferation only in phh and the human liver derived cell lines HepG2 and Chang. In contrast, EGF enhanced proliferation in all analyzed cell types including cell lines of colon, bronchial, pancreatic and gastric origin (SW480, BC1, L36PL and GC1). Conclusion: rhALR and EGF induce different kinetics of ERK and Akt phosphorylation in human hepatocytes. The mitogenic effect of rhALR is liver specific and seems to be at least partially independent from EGF receptor mediated signaling.

Stem cell  mediated liver regeneration:

DEFF Research Database (Denmark)

Jelnes, Peter

udformet en strategi som involverede isolering af HPCr vha. Fluorescent Activated Cell Sorting (FACS). Isolerede celler skulle efterfølgende undersøges ved in vitro studier som implicerede tilsætning af specifikke immunrespons relaterede faktorer. Kun få specifikke overflade HPC markører er blevet...

Bone marrow-derived mesenchymal stem cells effectively regenerate fibrotic liver in bile duct ligation rat model.

Science.gov (United States)

Mohamed, Hoda E; Elswefy, Sahar E; Rashed, Laila A; Younis, Nahla N; Shaheen, Mohamed A; Ghanim, Amal M H

2016-03-01

Mesenchymal stem cells (MSCs) have attracted lots of attention for the treatment of acute liver failure and end-stage liver diseases. This study aimed at investigating the fundamental mechanism by which bone marrow-derived MSCs (BM-MSCs) induce liver regeneration of fibrotic liver in rats. Rats underwent bile duct ligation (BDL) surgery and four weeks later they were treated with either BM-MSCs (3 × 10(6) cells /rat, once, tail vein injection) or silymarin (100 mg/kg, daily, orally) for four weeks. Liver function tests and hepatic oxidative stress were determined. Hepatic injury and fibrosis were assessed by H and E, Sirus red staining and immunohistochemical expression of α-smooth muscle actin (α-SMA). Hepatocyte growth factor (HGF) and the gene expression of cytokeratin-19 (CK-19) and matrix metalloproteinase-2 (MMP-2) in liver tissue were determined. BDL induced cholestatic liver injury characterized by elevated ALT and AST activities, bilirubin and decreased albumin. The architecture damage was staged as Metavir score: F3, A3. Fibrosis increased around proliferating bile duct as indicated by sirus red staining and α-SMA immunostaining. Fibrogenesis was favored over fibrolysis and confirmed by decreased HGF with increased expression of CK-19, but decreased MMP-2 expression. BM-MSCs treatment restored deteriorated liver functions and restored the histological changes, resolved fibrosis by improving liver regenerative capabilities (P liver regenerative capabilities can be stimulated by BM-MSCs via augmentation of HGF that subsequently up-regulate MMP-2 mRNA while downregulating CK-19 mRNA. © 2016 by the Society for Experimental Biology and Medicine.

Fibroblast growth factor 15/19 (FGF15/19) protects from diet-induced hepatic steatosis: development of an FGF19-based chimeric molecule to promote fatty liver regeneration.

Science.gov (United States)

Alvarez-Sola, Gloria; Uriarte, Iker; Latasa, M Ujue; Fernandez-Barrena, Maite G; Urtasun, Raquel; Elizalde, Maria; Barcena-Varela, Marina; Jiménez, Maddalen; Chang, Haisul C; Barbero, Roberto; Catalán, Victoria; Rodríguez, Amaia; Frühbeck, Gema; Gallego-Escuredo, José M; Gavaldà-Navarro, Aleix; Villarroya, Francesc; Rodriguez-Ortigosa, Carlos M; Corrales, Fernando J; Prieto, Jesus; Berraondo, Pedro; Berasain, Carmen; Avila, Matias A

2017-10-01

Fibroblast growth factor 15/19 (FGF15/19), an enterokine that regulates synthesis of hepatic bile acids (BA), has been proposed to influence fat metabolism. Without FGF15/19, mouse liver regeneration after partial hepatectomy (PH) is severely impaired. We studied the role of FGF15/19 in response to a high fat diet (HFD) and its regulation by saturated fatty acids. We developed a fusion molecule encompassing FGF19 and apolipoprotein A-I, termed Fibapo, and evaluated its pharmacological properties in fatty liver regeneration. Fgf15 -/- mice were fed a HFD. Liver fat and the expression of fat metabolism and endoplasmic reticulum (ER) stress-related genes were measured. Influence of palmitic acid (PA) on FGF15/19 expression was determined in mice and in human liver cell lines. In vivo half-life and biological activity of Fibapo and FGF19 were compared. Hepatoprotective and proregenerative activities of Fibapo were evaluated in obese db/db mice undergoing PH. Hepatosteatosis and ER stress were exacerbated in HFD-fed Fgf15 -/- mice. Hepatic expression of Pparγ2 was elevated in Fgf15 -/- mice, being reversed by FGF19 treatment. PA induced FGF15/19 expression in mouse ileum and human liver cells, and FGF19 protected from PA-mediated ER stress and cytotoxicity. Fibapo reduced liver BA and lipid accumulation, inhibited ER stress and showed enhanced half-life. Fibapo provided increased db/db mice survival and improved regeneration upon PH. FGF15/19 is essential for hepatic metabolic adaptation to dietary fat being a physiological regulator of Pparγ2 expression . Perioperative administration of Fibapo improves fatty liver regeneration. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Suppression of immune-mediated liver injury after vaccination with attenuated pathogenic cells.

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Mei, Yunhua; Wang, Ying; Xu, Lingyun

2007-05-15

Cell vaccination via immunization with attenuated pathogenic cells is an effective preventive method that has been successfully applied in several animal models of inflammatory or autoimmune diseases. Concanavalin A (Con A)-induced hepatitis (CIH) is a commonly used experimental model to study immune-mediated liver injury. Multiple cell types including T lymphocytes, macrophages and neutrophils have been found to be involved in the pathogenesis of CIH. In this study, we used attenuated spleen lymphocytes or peripheral blood lymphocytes as vaccines to investigate whether they could induce protective immune responses to prevent mice from developing CIH. We found that mice receiving such vaccination before CIH induction developed much milder diseases, exhibited a lower level of alanine aminotransferase (ALT) released into their plasma and had less inflammatory lesions in their livers. Such CIH-suppression is dose- and frequency-dependent. The suppressive effect was associated with inhibition of several major inflammatory mediators, pro-inflammatory cytokines and chemokines.

Sex Hormone-Related Functions in Regenerating Male Rat Liver

Science.gov (United States)

FRANCAVILLA, ANTONIO; EAGON, PATRICIA K.; DiLEO, ALFREDO; POLIMENO, LORENZO; PANELLA, CARMINE; AQUILINO, A. MARIA; INGROSSO, MARCELLO; Van THIEL, DAVID H.; STARZL, THOMAS E.

2011-01-01

Sex hormone receptors were quantitated in normal male rat liver and in regenerating liver at several different times after partial (70%) hepatectomy. Both estrogen and androgen receptor content were altered dramatically by partial hepatectomy. Total hepatic content and nuclear retention of estrogen receptors increased, with the zenith evident 2 days after partial hepatectomy, corresponding to the zenith of mitotic index. Serum estradiol increased after 1 day, and reached a maximum at 3 days after surgery. In contrast, total and nuclear androgen receptor content demonstrated a massive decline at 1, 2, and 3 days after resection. Serum testosterone displayed a parallel decline. In addition, hepatic content of two androgen-responsive proteins was reduced to 15% and 13% of normal values during this period. The activity of these various proteins during regeneration of male rat liver is comparable to that observed in the liver of normal female rats. Taken together, these results indicate that partial hepatectomy induces a feminization of certain sexually dimorphic aspects of liver function in male rats. Furthermore, these data provide evidence that estrogens, but not androgens, may have an important role in the process of liver regeneration. PMID:3758617

Whither prometheus' liver? Greek myth and the science of regeneration.

Science.gov (United States)

Power, Carl; Rasko, John E J

2008-09-16

Stem-cell biologists and those involved in regenerative medicine are fascinated by the story of Prometheus, the Greek god whose immortal liver was feasted on day after day by Zeus' eagle. This myth invariably provokes the question: Did the ancient Greeks know about the liver's amazing capacity for self-repair? The authors address this question by exploring the origins of Greek myth and medicine, adopting a 2-fold strategy. First, the authors consider what opportunities the ancient Greeks had to learn about the liver's structure and function. This involves a discussion of early battlefield surgery, the beginnings of anatomical research, and the ancient art of liver augury. In addition, the authors consider how the Greeks understood Prometheus' immortal liver. Not only do the authors examine the general theme of regeneration in Greek mythology, they survey several scholarly interpretations of Prometheus' torture.

Effects of Combined Anisodamine and Neostigmine Treatment on the Inflammatory Response and Liver Regeneration of Obstructive Jaundice Rats after Hepatectomy

Directory of Open Access Journals (Sweden)

Chong-Hui Li

2014-01-01

Full Text Available Background. Cholestasis is associated with high rates of morbidity and mortality in patients undergoing major liver resection. This study aimed to evaluate the effects of a combined anisodamine and neostigmine (Ani+Neo treatment on the inflammatory response and liver regeneration in rats with obstructive jaundice (OJ after partial hepatectomy. Materials and Methods. OJ was induced in the rats by bile duct ligation. After 7 days biliary drainage and partial hepatectomy were performed. These rats were assigned to a saline group or an Ani+Neo treatment group. The expressions of inflammatory mediators, liver regeneration, and liver damage were assessed at 48 h after hepatectomy. Results. The mRNA levels of TNF-α, IL-1β, IL-6, MCP-1, and MIP-1α, in the remnant livers, and the serum levels of TNF-α and IL-1β were substantially reduced in the Ani+Neo group compared with saline group (P<0.05. The Ani+Neo treatment obviously promoted liver regeneration as indicated by the liver weights and Ki-67 labeling index (P<0.05. The serum albumin and γ-GT levels and liver neutrophil infiltration also significantly improved in the Ani+Neo group (P<0.05 compared with the saline group. Conclusions. These results demonstrate that the combined anisodamine and neostigmine treatment is able to improve the liver regeneration in rats with OJ by substantially alleviating the inflammatory response.

Cytokines, hepatic cell profiling and cell interactions during bone marrow cell therapy for liver fibrosis in cholestatic mice.

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Daphne Pinheiro

Full Text Available Bone marrow cells (BMC migrate to the injured liver after transplantation, contributing to regeneration through multiple pathways, but mechanisms involved are unclear. This work aimed to study BMC migration, characterize cytokine profile, cell populations and proliferation in mice with liver fibrosis transplanted with GFP+ BMC. Confocal microscopy analysis showed GFP+ BMC near regions expressing HGF and SDF-1 in the fibrotic liver. Impaired liver cell proliferation in fibrotic groups was restored after BMC transplantation. Regarding total cell populations, there was a significant reduction in CD68+ cells and increased Ly6G+ cells in transplanted fibrotic group. BMC contributed to the total populations of CD144, CD11b and Ly6G cells in the fibrotic liver, related to an increment of anti-fibrotic cytokines (IL-10, IL-13, IFN-γ and HGF and reduction of pro-inflammatory cytokines (IL-17A and IL-6. Therefore, HGF and SDF-1 may represent important chemoattractants for transplanted BMC in the injured liver, where these cells can give rise to populations of extrahepatic macrophages, neutrophils and endothelial progenitor cells that can interact synergistically with other liver cells towards the modulation of an anti-fibrotic cytokine profile promoting the onset of liver regeneration.

Stem cell plasticity enables hair regeneration following Lgr5+ cell loss.

Science.gov (United States)

Hoeck, Joerg D; Biehs, Brian; Kurtova, Antonina V; Kljavin, Noelyn M; de Sousa E Melo, Felipe; Alicke, Bruno; Koeppen, Hartmut; Modrusan, Zora; Piskol, Robert; de Sauvage, Frederic J

2017-06-01

Under injury conditions, dedicated stem cell populations govern tissue regeneration. However, the molecular mechanisms that induce stem cell regeneration and enable plasticity are poorly understood. Here, we investigate stem cell recovery in the context of the hair follicle to understand how two molecularly distinct stem cell populations are integrated. Utilizing diphtheria-toxin-mediated cell ablation of Lgr5 + (leucine-rich repeat-containing G-protein-coupled receptor 5) stem cells, we show that killing of Lgr5 + cells in mice abrogates hair regeneration but this is reversible. During recovery, CD34 + (CD34 antigen) stem cells activate inflammatory response programs and start dividing. Pharmacological attenuation of inflammation inhibits CD34 + cell proliferation. Subsequently, the Wnt pathway controls the recovery of Lgr5 + cells and inhibition of Wnt signalling prevents Lgr5 + cell and hair germ recovery. Thus, our study uncovers a compensatory relationship between two stem cell populations and the underlying molecular mechanisms that enable hair follicle regeneration.

Kinetics of /sup 3/H-thymidine incorporation into nuclei of cells of the regenerating liver of rats exposed to various doses of x rays

Energy Technology Data Exchange (ETDEWEB)

Aksenovich, T I; Polishchuk, A M [AN SSSR, Novosibirsk. Inst. Tsitologii i Genetiki

1976-01-01

Action of x radiation on the incorporation of /sup 3/H-thymidine into nuclei of cells of the regenerating liver of rats has been studied. A whole-body exposure of rats to 150 to 300 R has been found to inhibit /sup 3/H-thymidine uptake into DNA of S-cells of the regenerating liver, and this effect can be attributed to the inhibition of DNA synthesis rather than to changes in the concentration of a label in the intracellular pool of DNA precursors. In addition to the DNA synthesis decrease, inhibition of the label uptake into the pool is observed after doses of 600 to 1200 R. On the basis of the data obtained, a hypothesis is proposed that explains the mechanism of inhibition of DNA synthesis under the action of radiation.

UPF2 is a critical regulator of liver development, function and regeneration

DEFF Research Database (Denmark)

Thoren, Lina A; Nørgaard, Gitte A; Weischenfeldt, Joachim

2010-01-01

regulatory potential of the NMD pathway in mammals will require the functional assessment of NMD in different tissues. METHODOLOGY/PRINCIPAL FINDINGS: Here we use mouse genetics to address the role of UPF2, a core NMD component, in the development, function and regeneration of the liver. We find that loss....... CONCLUSION/SIGNIFICANCE: Collectively, our data demonstrate the critical role of the NMD pathway in liver development, function and regeneration and highlights the importance of NMD for mammalian biology....... of NMD during fetal liver development is incompatible with postnatal life due to failure of terminal differentiation. Moreover, deletion of Upf2 in the adult liver results in hepatosteatosis and disruption of liver homeostasis. Finally, NMD was found to be absolutely required for liver regeneration...

Regeneration of hyaline cartilage by cell-mediated gene therapy using transforming growth factor beta 1-producing fibroblasts.

Science.gov (United States)

Lee, K H; Song, S U; Hwang, T S; Yi, Y; Oh, I S; Lee, J Y; Choi, K B; Choi, M S; Kim, S J

2001-09-20

Transforming growth factor beta (TGF-beta) has been considered as a candidate for gene therapy of orthopedic diseases. The possible application of cell-mediated TGF-beta gene therapy as a new treatment regimen for degenerative arthritis was investigated. In this study, fibroblasts expressing active TGF-beta 1 were injected into the knee joints of rabbits with artificially made cartilage defects to evaluate the feasibility of this therapy for orthopedic diseases. Two to 3 weeks after the injection there was evidence of cartilage regeneration, and at 4 to 6 weeks the cartilage defect was completely filled with newly grown hyaline cartilage. Histological analyses of the regenerated cartilage suggested that it was well integrated with the adjacent normal cartilage at the sides of the defect and that the newly formed tissue was indeed hyaline cartilage. Our findings suggest that cell-mediated TGF-beta 1 gene therapy may be a novel treatment for orthopedic diseases in which hyaline cartilage damage has occurred.

CAR-mediated repression of Foxo1 transcriptional activity regulates the cell cycle inhibitor p21 in mouse livers

International Nuclear Information System (INIS)

Kazantseva, Yuliya A.; Yarushkin, Andrei A.; Pustylnyak, Vladimir O.

2014-01-01

Highlights: • CAR activation decreased the level of Foxo1 in mouse livers. • CAR activation decreased the level of p21 in mouse livers. • CAR activation inhibited Foxo1 transcriptional activity in mouse livers. - Abstract: 1,4-Bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP), an agonist of constitutive androstane receptor (CAR), is a well-known strong primary chemical mitogen for the mouse liver. Despite extensive investigation of the role of CAR in the regulation of cell proliferation, our knowledge of the intricate mediating mechanism is incomplete. In this study, we demonstrated that long-term CAR activation by TCPOBOP increased liver-to-body weight ratio and decreased tumour suppressor Foxo1 expression and transcriptional activity, which were correlated with reduced expression of genes regulated by Foxo1, including the cell-cycle inhibitor Cdkn1a(p21), and upregulation of the cell-cycle regulator Cyclin D1. Moreover, we demonstrated the negative regulatory effect of TCPOBOP-activated CAR on the association of Foxo1 with the target Foxo1 itself and Cdkn1a(p21) promoters. Thus, we identified CAR-mediated repression of cell cycle inhibitor p21, as mediated by repression of FOXO1 expression and transcriptional activity. CAR-FOXO1 cross-talk may provide new opportunities for understanding liver diseases and developing more effective therapeutic approaches to better drug treatments

Evaluation of regeneration of liver function in pig model of auxiliary partial liver transplantation

International Nuclear Information System (INIS)

Li Jiaxin; Chen Xiaopeng; Rui Ging; Shong Qun; Chen Fangman; Lu Meijing; Chen Yongquan

2010-01-01

Objective: To establish a pig model of auxiliary partial liver transplantation and observe the liver function regeneration of host liver and graft. Methods: The portal vein providing for the host liver were gradually contracted; the donor hepatic veins were eng-to-side anastomosed to inferior vena cava in host caudal; graft was transplanted into the space under the host liver, part of receivers relieved portal vein angiography and color Doppler flow imaging was performed 3 days after surgery. Liver function of double livers in relievers was checked up, 3 days and 1 week after surgery respectively. Results: After surgery 10 relievers survived over 1 week, blood enzymology from hepatic vein of grafts 1 week after surgery were not ameliorative significantly compared with those 3 days after surgery (P > 0.05). Blood enzymology indexes from hepatic veins of grafts 1 week after surgery were were improved significantly compared with 3 days after surgery (P < 0.05). The graft did not reveal atrophic and gained favorable function. Conclusion: Favorable regeneration in the auxiliary partial liver transplantation model has achieved. Ideal foundation has been established for simulating and investigating human auxiliary liver transplantation. (authors)

Metallothionein expression during liver regeneration after partial hepatectomy in cadmium-pretreated rats

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Margeli, A.P. (Dept. of Forensic Medicine and Toxicology, School of Medicine, Univ. of Athens (Greece)); Theocharis, S.E. (Dept. of Forensic Medicine and Toxicology, School of Medicine, Univ. of Athens (Greece)); Yannacou, N.N. (Dept. of Forensic Medicine and Toxicology, School of Medicine, Univ. of Athens (Greece)); Spiliopoulou, C. (Dept. of Forensic Medicine and Toxicology, School of Medicine, Univ. of Athens (Greece)); Koutselinis, A. (Dept. of Forensic Medicine and Toxicology, School of Medicine, Univ. of Athens (Greece))

1994-10-01

Metallothionein is a low molecular mass protein inducible mainly by heavy metals, having high affinity for binding cadmium, zinc and copper. In the present study we investigated the expression of metallothionein in regenerating liver, at different time intervals, in cadmium pretreated partially hepatectomized rats. Liver metallothionein is highly expressed during regeneration induced by partial hepatectomy in rats, providing zinc within the rapidly growing tissue. Cadmium pretreatment caused inhibition of the first peak of liver regeneration, while metallothionein expression was markedly more prominent in the liver residues of cadmium-pretreated rats. These results demonstrate that although metallothionein able to bind temporarily metal ions as zinc and cadmium has been highly expressed, the liver regenerative process was inhibited possibly due to the effects of cadmium on other pivotal events necessary to the DNA replication. (orig.)

HIF-1{alpha} is necessary to support gluconeogenesis during liver regeneration

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Tajima, Toshihide [Department of Obstetrics and Gynecology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Goda, Nobuhito, E-mail: goda@waseda.jp [Department of Life Science and Medical Bio-Science, School of Advanced Science and Engineering, Waseda University, TWIns 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480 (Japan); Fujiki, Natsuko; Hishiki, Takako; Nishiyama, Yasumasa [Department of Biochemistry and Integrative Medical Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Senoo-Matsuda, Nanami [Department of Life Science and Medical Bio-Science, School of Advanced Science and Engineering, Waseda University, TWIns 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480 (Japan); Shimazu, Motohide [Department of Surgery, Tokyo Medical University Hachioji Medical Center, 1163 Tatemachi, Hachioji, Tokyo 193-0998 (Japan); Soga, Tomoyoshi [The Institute for Advanced Biosciences, Keio University, Tsuruoka City, Yamagata 997-0052 (Japan); Yoshimura, Yasunori [Department of Obstetrics and Gynecology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Johnson, Randall S. [Molecular Biology Section, Division of Biology, University of California, San Diego, La Jolla, CA 92093 (United States); Suematsu, Makoto [Department of Biochemistry and Integrative Medical Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan)

2009-10-02

Coordinated recovery of hepatic glucose metabolism is prerequisite for normal liver regeneration. To examine roles of hypoxia inducible factor-1{alpha} (HIF-1{alpha}) for hepatic glucose homeostasis during the reparative process, we inactivated the gene in hepatocytes in vivo. Following partial hepatectomy (PH), recovery of residual liver weight was initially retarded in the mutant mice by down-regulation of hepatocyte proliferation, but occurred comparably between the mutant and control mice at 72 h after PH. At this time point, the mutant mice showed lowered blood glucose levels with enhanced accumulation of glycogen in the liver. The mutant mice exhibited impairment of hepatic gluconeogenesis as assessed by alanine tolerance test. This appeared to result from reduced expression of PGK-1 and PEPCK since 3-PG, PEP and malate were accumulated to greater extents in the regenerated liver. In conclusion, these findings provide evidence for roles of HIF-1{alpha} in the regulation of gluconeogenesis under liver regeneration.

HIF-1α is necessary to support gluconeogenesis during liver regeneration

International Nuclear Information System (INIS)

Tajima, Toshihide; Goda, Nobuhito; Fujiki, Natsuko; Hishiki, Takako; Nishiyama, Yasumasa; Senoo-Matsuda, Nanami; Shimazu, Motohide; Soga, Tomoyoshi; Yoshimura, Yasunori; Johnson, Randall S.; Suematsu, Makoto

2009-01-01

Coordinated recovery of hepatic glucose metabolism is prerequisite for normal liver regeneration. To examine roles of hypoxia inducible factor-1α (HIF-1α) for hepatic glucose homeostasis during the reparative process, we inactivated the gene in hepatocytes in vivo. Following partial hepatectomy (PH), recovery of residual liver weight was initially retarded in the mutant mice by down-regulation of hepatocyte proliferation, but occurred comparably between the mutant and control mice at 72 h after PH. At this time point, the mutant mice showed lowered blood glucose levels with enhanced accumulation of glycogen in the liver. The mutant mice exhibited impairment of hepatic gluconeogenesis as assessed by alanine tolerance test. This appeared to result from reduced expression of PGK-1 and PEPCK since 3-PG, PEP and malate were accumulated to greater extents in the regenerated liver. In conclusion, these findings provide evidence for roles of HIF-1α in the regulation of gluconeogenesis under liver regeneration.

The circadian optimal time for hepatectomy in the study of liver regeneration.

Science.gov (United States)

Souto, M; Llanos, J M

1985-01-01

Standardized (light from 0600 to 1800) C3HS mice, hepatectomized at different circadian stages, were killed at 1400 (the peak time of mitotic activity in intact mice). The higher values of mitotic index were those of mice operated at 1400, 48 hr before. The curve of mitotic activity of the regenerating liver of mice operated at 1400 and that of mice operated at 0200 (an opposite time in the circadian stage) are, both, grossly in phase with the curves of mitotic index in young and adult mice liver. The amplitude of the first peak of mitotic activity in mice operated at 0200 was dramatically lower than that of animals operated at 1400. The same applies to hepatocytes as well as to the sinusoid litoral population of cells. It is concluded that 1400 hr, as contrast to 0200 hr, is an optimal time for hepatectomy if one wants to obtain the highest mitotic index first peak during regeneration in a normal phase position (the position of the mitotic index peak in the liver of normal young and adult mice).

Methylation of Septin9 mediated by DNMT3a enhances hepatic stellate cells activation and liver fibrogenesis

Energy Technology Data Exchange (ETDEWEB)

Wu, Yuting, E-mail: wuyuting1302@sina.com; Bu, Fangtian; Yu, Haixia; Li, Wanxia; Huang, Cheng; Meng, Xiaoming; Zhang, Lei; Ma, Taotao; Li, Jun, E-mail: lj@ahmu.edu.cn

2017-01-15

Liver fibrosis, resulting from chronic and persistent injury to the liver, is a worldwide health problem. Advanced liver fibrosis results in cirrhosis, liver failure and even hepatocellular cancer (HCC), often eventually requiring liver transplantation, poses a huge health burden on the global community. However, the specific pathogenesis of liver fibrosis remains not fully understood. Numerous basic and clinical studies have provided evidence that epigenetic modifications, especially DNA methylation, might contribute to the activation of hepatic stellate cells (HSCs), the pivotal cell type responsible for the fibrous scar in liver. Here, reduced representation bisulfite sequencing (RRBS) and bisulfite pyrosequencing PCR (BSP) analysis identified hypermethylation status of Septin9 (Sept9) gene in liver fibrogenesis. Sept9 protein was dramatically decreased in livers of CCl4-treated mice and immortalized HSC-T6 cells exposed to TGF-β1. Nevertheless, the suppression of Sept9 could be blocked by DNMT3a-siRNA and DNA methyltransferase inhibitor, 5-aza-2′-deoxycytidine (5-azadC). Overexpressed Sept9 attenuated TGF-β1-induced expression of myofibroblast markers α-SMA and Col1a1, accompanied by up-regulation of cell apoptosis-related proteins. Conversely, RNAi-mediated silencing of Sept9 enhanced accumulation of extracellular matrix. These observations suggested that Sept9 contributed to alleviate liver fibrosis might partially through promoting activated HSCs apoptosis and this anti-fibrogenesis effect might be blocked by DNMT-3a mediated methylation of Sept9. Therefore, pharmacological agents that inhibit Sept9 methylation and increase its expression could be considered as valuable treatments for liver fibrosis. - Highlights: • This is the first report of Sept9 methylation and function in liver fibrosis. • Ectopic expression of Sept9 could block the liver fibrogenesis. • DNMT3a might be responsible for the suppression of Sept9 in liver fibrosis.

Methylation of Septin9 mediated by DNMT3a enhances hepatic stellate cells activation and liver fibrogenesis

International Nuclear Information System (INIS)

Wu, Yuting; Bu, Fangtian; Yu, Haixia; Li, Wanxia; Huang, Cheng; Meng, Xiaoming; Zhang, Lei; Ma, Taotao; Li, Jun

2017-01-01

Liver fibrosis, resulting from chronic and persistent injury to the liver, is a worldwide health problem. Advanced liver fibrosis results in cirrhosis, liver failure and even hepatocellular cancer (HCC), often eventually requiring liver transplantation, poses a huge health burden on the global community. However, the specific pathogenesis of liver fibrosis remains not fully understood. Numerous basic and clinical studies have provided evidence that epigenetic modifications, especially DNA methylation, might contribute to the activation of hepatic stellate cells (HSCs), the pivotal cell type responsible for the fibrous scar in liver. Here, reduced representation bisulfite sequencing (RRBS) and bisulfite pyrosequencing PCR (BSP) analysis identified hypermethylation status of Septin9 (Sept9) gene in liver fibrogenesis. Sept9 protein was dramatically decreased in livers of CCl4-treated mice and immortalized HSC-T6 cells exposed to TGF-β1. Nevertheless, the suppression of Sept9 could be blocked by DNMT3a-siRNA and DNA methyltransferase inhibitor, 5-aza-2′-deoxycytidine (5-azadC). Overexpressed Sept9 attenuated TGF-β1-induced expression of myofibroblast markers α-SMA and Col1a1, accompanied by up-regulation of cell apoptosis-related proteins. Conversely, RNAi-mediated silencing of Sept9 enhanced accumulation of extracellular matrix. These observations suggested that Sept9 contributed to alleviate liver fibrosis might partially through promoting activated HSCs apoptosis and this anti-fibrogenesis effect might be blocked by DNMT-3a mediated methylation of Sept9. Therefore, pharmacological agents that inhibit Sept9 methylation and increase its expression could be considered as valuable treatments for liver fibrosis. - Highlights: • This is the first report of Sept9 methylation and function in liver fibrosis. • Ectopic expression of Sept9 could block the liver fibrogenesis. • DNMT3a might be responsible for the suppression of Sept9 in liver fibrosis.

Concomitant apoptosis and regeneration of liver cells as a mechanism of liver-tumor promotion by β-naphthoflavone involving TNFα-signaling due to oxidative cellular stress in rats

International Nuclear Information System (INIS)

Kuwata, Kazunori; Shibutani, Makoto; Hayashi, Hitomi; Shimamoto, Keisuke; Hayashi, Shim-Mo; Suzuki, Kazuhiko; Mitsumori, Kunitoshi

2011-01-01

β-Naphthoflavone (BNF) is a strong inducer of cytochrome P450 1A enzymes, and exerts liver tumor-promoting activity through enhancement of oxidative stress responses in rats. This study investigated the role of the tissue environment surrounding hepatocellular preneoplastic lesions in the early tumor-promotion stage by BNF, using enzymatically modified isoquercitrin (EMIQ) as an anti-oxidative chemopreventive agent. Male F344 rats were fed a diet containing BNF (0.5%) for 6 weeks, with or without EMIQ (0.2%) in the drinking water, 2 weeks after initiation with N-diethylnitrosamine, and were subjected to two-thirds partial hepatectomy 1 week after starting BNF-promotion. BNF-treatment increased concentrations of liver thiobarbituric acid-reactive substances, single liver cells expressing glutathione S-transferase placental form or heme oxygenase (HO)-1, and concomitant apoptosis and proliferation of liver cells. Transcript upregulation of anti-oxidative enzymes (Aldh1a1 and Nqo1), cell cycle-related molecules (Cdc20 and Cdkn2b) and inflammation-related molecules including proinflammatory cytokines (Ccl2, Col1a1, Il6, Nos2 and Serpine1) was also evident. Furthermore, BNF increased HO-1-expressing Kupffer cells and liver cells expressing tumor necrosis factor receptor 1 (TNFR1) and the TNFR1-associated death domain. Most of these BNF-induced fluctuations disappeared or were suppressed by EMIQ in conjunction with suppression of tumor-promotion. Tnf transcript levels with BNF were also suppressed by EMIQ. These results suggest that BNF-induced oxidative stress causes single liver cell toxicity, allowing subsequent concomitant apoptosis and regeneration involving inflammatory responses including TNFα-signaling, contributing to tumor promotion. Kupffer cells may act to protect against inflammatory stimuli induced as a result of oxidative cellular stress by BNF, causing proinflammatory cytokine level fluctuations.

Germ cell regeneration-mediated, enhanced mutagenesis in the ascidian Ciona intestinalis reveals flexible germ cell formation from different somatic cells.

Science.gov (United States)

Yoshida, Keita; Hozumi, Akiko; Treen, Nicholas; Sakuma, Tetsushi; Yamamoto, Takashi; Shirae-Kurabayashi, Maki; Sasakura, Yasunori

2017-03-15

The ascidian Ciona intestinalis has a high regeneration capacity that enables the regeneration of artificially removed primordial germ cells (PGCs) from somatic cells. We utilized PGC regeneration to establish efficient methods of germ line mutagenesis with transcription activator-like effector nucleases (TALENs). When PGCs were artificially removed from animals in which a TALEN pair was expressed, somatic cells harboring mutations in the target gene were converted into germ cells, this germ cell population exhibited higher mutation rates than animals not subjected to PGC removal. PGC regeneration enables us to use TALEN expression vectors of specific somatic tissues for germ cell mutagenesis. Unexpectedly, cis elements for epidermis, neural tissue and muscle could be used for germ cell mutagenesis, indicating there are multiple sources of regenerated PGCs, suggesting a flexibility of differentiated Ciona somatic cells to regain totipotency. Sperm and eggs of a single hermaphroditic, PGC regenerated animal typically have different mutations, suggesting they arise from different cells. PGCs can be generated from somatic cells even though the maternal PGCs are not removed, suggesting that the PGC regeneration is not solely an artificial event but could have an endogenous function in Ciona. This study provides a technical innovation in the genome-editing methods, including easy establishment of mutant lines. Moreover, this study suggests cellular mechanisms and the potential evolutionary significance of PGC regeneration in Ciona. Copyright © 2017 Elsevier Inc. All rights reserved.

Adult Lung Spheroid Cells Contain Progenitor Cells and Mediate Regeneration in Rodents With Bleomycin-Induced Pulmonary Fibrosis.

Science.gov (United States)

Henry, Eric; Cores, Jhon; Hensley, M Taylor; Anthony, Shirena; Vandergriff, Adam; de Andrade, James B M; Allen, Tyler; Caranasos, Thomas G; Lobo, Leonard J; Cheng, Ke

2015-11-01

Lung diseases are devastating conditions and ranked as one of the top five causes of mortality worldwide according to the World Health Organization. Stem cell therapy is a promising strategy for lung regeneration. Previous animal and clinical studies have focused on the use of mesenchymal stem cells (from other parts of the body) for lung regenerative therapies. We report a rapid and robust method to generate therapeutic resident lung progenitors from adult lung tissues. Outgrowth cells from healthy lung tissue explants are self-aggregated into three-dimensional lung spheroids in a suspension culture. Without antigenic sorting, the lung spheroids recapitulate the stem cell niche and contain a natural mixture of lung stem cells and supporting cells. In vitro, lung spheroid cells can be expanded to a large quantity and can form alveoli-like structures and acquire mature lung epithelial phenotypes. In severe combined immunodeficiency mice with bleomycin-induced pulmonary fibrosis, intravenous injection of human lung spheroid cells inhibited apoptosis, fibrosis, and infiltration but promoted angiogenesis. In a syngeneic rat model of pulmonary fibrosis, lung spheroid cells outperformed adipose-derived mesenchymal stem cells in reducing fibrotic thickening and infiltration. Previously, lung spheroid cells (the spheroid model) had only been used to study lung cancer cells. Our data suggest that lung spheroids and lung spheroid cells from healthy lung tissues are excellent sources of regenerative lung cells for therapeutic lung regeneration. The results from the present study will lead to future human clinical trials using lung stem cell therapies to treat various incurable lung diseases, including pulmonary fibrosis. The data presented here also provide fundamental knowledge regarding how injected stem cells mediate lung repair in pulmonary fibrosis. ©AlphaMed Press.

ATP Binding cassette transporter gene expression in rat liver progenitor cells

NARCIS (Netherlands)

Ros, J.E.; Roskams, T.A.D.; Geuken, M.; Havinga, R.; Splinter, P.L.; Petersen, B.E.; LaRusso, N.F.; Kolk, van der D.M.; Kuipers, F.; Faber, K.N.; Müller, M.R.; Jansen, P.L.M.

2003-01-01

Background and aim: Liver regeneration after severe liver damage depends in part on proliferation and differentiation of hepatic progenitor cells (HPCs). Under these conditions they must be able to withstand the toxic milieu of the damaged liver. ATP binding cassette (ABC) transporters are

ATP binding cassette transporter gene expression in rat liver progenitor cells

NARCIS (Netherlands)

Ros, J. E.; Roskams, T. A. D.; Geuken, M.; Havinga, R.; Splinter, P. L.; Petersen, B. E.; LaRusso, N. F.; van der Kolk, D. M.; Kuipers, F.; Faber, K. N.; Müller, M.; Jansen, P. L. M.

2003-01-01

BACKGROUND AND AIM: Liver regeneration after severe liver damage depends in part on proliferation and differentiation of hepatic progenitor cells (HPCs). Under these conditions they must be able to withstand the toxic milieu of the damaged liver. ATP binding cassette (ABC) transporters are

ATP binding cassette transporter gene expression in rat liver progenitor cells

NARCIS (Netherlands)

Ros, J.E.; Roskams, TAD; Geuken, M; Havinga, R; Splinter, PL; Petersen, BE; LaRusso, NF; van der Kolk, D.M.; Kuipers, F; Faber, KN; Muller, M; Jansen, PLM

Background and aim: Liver regeneration after severe liver damage depends in part on proliferation and differentiation of hepatic progenitor cells (HPCs). Under these conditions they must be able to withstand the toxic milieu of the damaged liver. ATP binding cassette (ABC) transporters are

microRNA 21-mediated suppression of Sprouty1 by Pokemon affects liver cancer cell growth and proliferation.

Science.gov (United States)

Jin, Xiu-Li; Sun, Qin-Sheng; Liu, Feng; Yang, Hong-Wei; Liu, Min; Liu, Hong-Xia; Xu, Wei; Jiang, Yu-Yang

2013-07-01

Transcriptional repressor Pokemon is a critical factor in embryogenesis, development, cell proliferation, differentiation, and oncogenesis, thus behaving as an oncogene. Oncomine database suggests a potential correlation between the expressions of Pokemon and Sprouty1. This study investigated the regulatory role of Pokemon in Sprouty1 expression and the effect on liver cancer cell growth and proliferation, revealing a novel miR-21-mediated regulatory circuit. In normal (HL-7702) and cancer (QGY-7703) liver cell lines, Sprouty1 expression is inversely correlated with Pokemon levels. Targeted expression or siRNA-mediated silencing showed that Pokemon is a repressor of Sprouty1 expression at both mRNA and protein levels, but Pokemon cannot affect the promoter activity of Sprouty1. Sprouty1 is a target of miR-21 and interestingly, we found that miR-21 is up-regulated by Pokemon in liver cancer cells. Luciferase reporter assays showed that Pokemon up-regulated miR-21 transcription in a dose-dependent manner, and ChIP assay exhibited a direct binding of Pokemon to the miR-21 promoter at -747 to -399 bp. Site-directed mutagenesis of the GC boxes at -684 to -679 bp and -652 to -647 bp of miR-21 promoter abolished the regulatory activity by Pokemon. Furthermore, we found that the modulation of Pokemon and miR-21 expression affected the growth and proliferation of liver cancer cells QGY-7703. In summary, our findings demonstrate that Pokemon suppresses Sprouty1 expression through a miR-21-mediated mechanism, affecting the growth and proliferation of liver cancer cells. This study recognized miR-21 and Sprouty1 as novel targets of the Pokemon regulatory network. Copyright © 2013 Wiley Periodicals, Inc.

Implications of microbiota and bile acid in liver injury and regeneration.

Science.gov (United States)

Liu, Hui-Xin; Keane, Ryan; Sheng, Lili; Wan, Yu-Jui Yvonne

2015-12-01

Studies examining the mechanisms by which the liver incurs injury and then regenerates usually focus on factors and pathways directly within the liver, neglecting the signaling derived from the gut-liver axis. The intestinal content is rich in microorganisms as well as metabolites generated from both the host and colonizing bacteria. Through the gut-liver axis, this complex "soup" exerts an immense impact on liver integrity and function. This review article summarizes data published in the past 30 years demonstrating the signaling derived from the gut-liver axis in relation to liver injury and regeneration. Due to the intricate networks of implicated pathways as well as scarcity of available mechanistic data, it seems that nutrigenomic, metabolomics, and microbiota profiling approaches are warranted to provide a better understanding regarding the interplay and impact between nutrition, bacteria, and host response in influencing liver function and healing. Therefore elucidating the possible molecular mechanisms that link microbiota alteration to host physiological response and vice versa. Published by Elsevier B.V.

Liver remnant regeneration in donors after living donor liver transplantation. Long-term follow-up using CT and MR imaging

Energy Technology Data Exchange (ETDEWEB)

Klink, T. [INSELSPITAL - Bern University Hospital (Switzerland). Diagnostic, Interventional, and Pediatric Radiology; University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Diagnostic and Interventional Radiology; Simon, P. [Merciful Brethren Hospital, Trier (Germany). Dept. of Radiology, Neuroradiology, Sonography and Nuclearmedicine; University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Diagnostic and Interventional Radiology; Knopp, C.; Ittrich, H.; Adam, G.; Koops, A. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Diagnostic and Interventional Radiology; Fischer, L. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Hepatobiliary Surgery and Transplant Surgery

2014-06-15

Purpose: To assess liver remnant volume regeneration and maintenance, and complications in the long-time follow-up of donors after living donor liver transplantation using CT and MRI. Materials and Methods: 47 donors with a mean age of 33.5 years who donated liver tissue for transplantation and who were available for follow-up imaging were included in this retrospective study. Contrast-enhanced CT and MR studies were acquired for routine follow-up. Two observers evaluated pre- and postoperative images regarding anatomy and pathological findings. Volumes were manually measured on contrast-enhanced images in the portal venous phase, and potential postoperative complications were documented. Pre- and postoperative liver volumes were compared for evaluating liver remnant regeneration. Results: 47 preoperative and 89 follow-up studies covered a period of 22.4 months (range: 1 - 84). After right liver lobe (RLL) donation, the mean liver remnant volume was 522.0 ml (± 144.0; 36.1%; n = 18), after left lateral section (LLS) donation 1,121.7 ml (± 212.8; 79.9%; n = 24), and after left liver lobe (LLL) donation 1,181.5 ml (± 279.5; 72.0%; n = 5). Twelve months after donation, the liver remnant volume were 87.3% (RLL; ± 11.8; n = 11), 95.0% (LS; ± 11.6; n = 18), and 80.1% (LLL; ± 2.0; n = 2 LLL) of the preoperative total liver volume. Rapid initial regeneration and maintenance at 80% of the preoperative liver volume were observed over the total follow-up period. Minor postoperative complications were found early in 4 patients. No severe or late complications or mortality occurred. Conclusion: Rapid regeneration of liver remnant volumes in all donors and volume maintenance over the long-term follow-up period of up to 84 months without severe or late complications are important observations for assessing the safety of LDLT donors. (orig.)

Liver remnant regeneration in donors after living donor liver transplantation. Long-term follow-up using CT and MR imaging

International Nuclear Information System (INIS)

Klink, T.; University Medical Center Hamburg-Eppendorf, Hamburg; Simon, P.; University Medical Center Hamburg-Eppendorf, Hamburg; Knopp, C.; Ittrich, H.; Adam, G.; Koops, A.; Fischer, L.

2014-01-01

Purpose: To assess liver remnant volume regeneration and maintenance, and complications in the long-time follow-up of donors after living donor liver transplantation using CT and MRI. Materials and Methods: 47 donors with a mean age of 33.5 years who donated liver tissue for transplantation and who were available for follow-up imaging were included in this retrospective study. Contrast-enhanced CT and MR studies were acquired for routine follow-up. Two observers evaluated pre- and postoperative images regarding anatomy and pathological findings. Volumes were manually measured on contrast-enhanced images in the portal venous phase, and potential postoperative complications were documented. Pre- and postoperative liver volumes were compared for evaluating liver remnant regeneration. Results: 47 preoperative and 89 follow-up studies covered a period of 22.4 months (range: 1 - 84). After right liver lobe (RLL) donation, the mean liver remnant volume was 522.0 ml (± 144.0; 36.1%; n = 18), after left lateral section (LLS) donation 1,121.7 ml (± 212.8; 79.9%; n = 24), and after left liver lobe (LLL) donation 1,181.5 ml (± 279.5; 72.0%; n = 5). Twelve months after donation, the liver remnant volume were 87.3% (RLL; ± 11.8; n = 11), 95.0% (LS; ± 11.6; n = 18), and 80.1% (LLL; ± 2.0; n = 2 LLL) of the preoperative total liver volume. Rapid initial regeneration and maintenance at 80% of the preoperative liver volume were observed over the total follow-up period. Minor postoperative complications were found early in 4 patients. No severe or late complications or mortality occurred. Conclusion: Rapid regeneration of liver remnant volumes in all donors and volume maintenance over the long-term follow-up period of up to 84 months without severe or late complications are important observations for assessing the safety of LDLT donors. (orig.)

Interleukin-1 receptor antagonist modulates the early phase of liver regeneration after partial hepatectomy in mice.

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Antonino Sgroi

Full Text Available BACKGROUND: Cytokine administration is a potential therapy for acute liver failure by reducing inflammatory responses and favour hepatocyte regeneration. The aim of this study was to evaluate the role of interleukin-1 receptor antagonist (IL-1ra during liver regeneration and to study the effect of a recombinant human IL-1ra on liver regeneration. METHODS: We performed 70%-hepatectomy in wild type (WT mice, IL-1ra knock-out (KO mice and in WT mice treated by anakinra. We analyzed liver regeneration at regular intervals by measuring the blood levels of cytokines, the hepatocyte proliferation by bromodeoxyuridin (BrdU incorporation, proliferating cell nuclear antigen (PCNA and Cyclin D1 expression. The effect of anakinra on hepatocyte proliferation was also tested in vitro using human hepatocytes. RESULTS: At 24h and at 48 h after hepatectomy, IL-1ra KO mice had significantly higher levels of pro-inflammatory cytokines (IL-6, IL-1β and MCP-1 and a reduced and delayed hepatocyte proliferation measured by BrdU incorporation, PCNA and Cyclin D1 protein levels, when compared to WT mice. IGFBP-1 and C/EBPβ expression was significantly decreased in IL-1ra KO compared to WT mice. WT mice treated with anakinra showed significantly decreased levels of IL-6 and significantly higher hepatocyte proliferation at 24h compared to untreated WT mice. In vitro, primary human hepatocytes treated with anakinra showed significantly higher proliferation at 24h compared to hepatocytes without treatment. CONCLUSION: IL1ra modulates the early phase of liver regeneration by decreasing the inflammatory stress and accelerating the entry of hepatocytes in proliferation. IL1ra might be a therapeutic target to improve hepatocyte proliferation.

TWEAK induces liver progenitor cell proliferation

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Jakubowski, Aniela; Ambrose, Christine; Parr, Michael; Lincecum, John M.; Wang, Monica Z.; Zheng, Timothy S.; Browning, Beth; Michaelson, Jennifer S.; Baestcher, Manfred; Wang, Bruce; Bissell, D. Montgomery; Burkly, Linda C.

2005-01-01

Progenitor (“oval”) cell expansion accompanies many forms of liver injury, including alcohol toxicity and submassive parenchymal necrosis as well as experimental injury models featuring blocked hepatocyte replication. Oval cells can potentially become either hepatocytes or biliary epithelial cells and may be critical to liver regeneration, particularly when hepatocyte replication is impaired. The regulation of oval cell proliferation is incompletely understood. Herein we present evidence that a TNF family member called TWEAK (TNF-like weak inducer of apoptosis) stimulates oval cell proliferation in mouse liver through its receptor Fn14. TWEAK has no effect on mature hepatocytes and thus appears to be selective for oval cells. Transgenic mice overexpressing TWEAK in hepatocytes exhibit periportal oval cell hyperplasia. A similar phenotype was obtained in adult wild-type mice, but not Fn14-null mice, by administering TWEAK-expressing adenovirus. Oval cell expansion induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) was significantly reduced in Fn14-null mice as well as in adult wild-type mice with a blocking anti-TWEAK mAb. Importantly, TWEAK stimulated the proliferation of an oval cell culture model. Finally, we show increased Fn14 expression in chronic hepatitis C and other human liver diseases relative to its expression in normal liver, which suggests a role for the TWEAK/Fn14 pathway in human liver injury. We conclude that TWEAK has a selective mitogenic effect for liver oval cells that distinguishes it from other previously described growth factors. PMID:16110324

Nuclear receptor CAR (NR1I3) is essential for DDC-induced liver injury and oval cell proliferation in mouse liver.

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Yamazaki, Yuichi; Moore, Rick; Negishi, Masahiko

2011-11-01

The liver is endowed with the ability to regenerate hepatocytes in response to injury. When this regeneration ability is impaired during liver injury, oval cells, which are considered to be postnatal hepatic progenitors, proliferate and differentiate into hepatocytes. Here we have demonstrated that 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) activates the nuclear receptor constitutive active/androstane receptor (CAR), resulting in proliferation of oval cells in mouse liver. Activation of CAR by DDC was shown by hepatic nuclear CAR accumulation and cytochrome P450 (CYP)2B10 mRNA induction after feeding a 0.1% DDC-containing diet to Car(+/+) mice. After being fed the DDC diet, Car(+/+), but not Car(-/-) mice, developed severe liver injury and an A6 antibody-stained ductular reaction in an area around the portal tract. Oval cell proliferation was confirmed by laser capture microdissection and real-time PCR; mRNAs for the two oval cell markers epithelial cell adhesion molecule and TROP2 were specifically induced in the periportal region of DDC diet-fed Car(+/+), but not Car(-/-) mice. Although rates of both hepatocyte growth and death were initially enhanced only in DDC diet-fed Car(+/+) mice, growth was attenuated when oval cells proliferated, whereas death continued unabated. DDC-induced liver injury, which differs from other CAR activators such as phenobarbital, occurred in the periportal region where cells developed hypertrophy, accumulated porphyrin crystals and inflammation developed, all in association with the proliferation of oval cells. Thus, CAR provides an excellent experimental model for further investigations into its roles in liver regeneration, as well as the development of diseases such as hepatocellular carcinoma.

Fibronectin Extra Domain A Promotes Liver Sinusoid Repair following Hepatectomy.

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Bridget Sackey-Aboagye

Full Text Available Liver sinusoidal endothelial cells (LSECs are the main endothelial cells in the liver and are important for maintaining liver homeostasis as well as responding to injury. LSECs express cellular fibronectin containing the alternatively spliced extra domain A (EIIIA-cFN and increase expression of this isoform after liver injury, although its function is not well understood. Here, we examined the role of EIIIA-cFN in liver regeneration following partial hepatectomy. We carried out two-thirds partial hepatectomies in mice lacking EIIIA-cFN and in their wild type littermates, studied liver endothelial cell adhesion on decellularized, EIIIA-cFN-containing matrices and investigated the role of cellular fibronectins in liver endothelial cell tubulogenesis. We found that liver weight recovery following hepatectomy was significantly delayed and that sinusoidal repair was impaired in EIIIA-cFN null mice, especially females, as was the lipid accumulation typical of the post-hepatectomy liver. In vitro, we found that liver endothelial cells were more adhesive to cell-deposited matrices containing the EIIIA domain and that cellular fibronectin enhanced tubulogenesis and vascular cord formation. The integrin α9β1, which specifically binds EIIIA-cFN, promoted tubulogenesis and adhesion of liver endothelial cells to EIIIA-cFN. Our findings identify a role for EIIIA-cFN in liver regeneration and tubulogenesis. We suggest that sinusoidal repair is enhanced by increased LSEC adhesion, which is mediated by EIIIA-cFN.

A Complex Interplay between Wnt/β-Catenin Signalling and the Cell Cycle in the Adult Liver

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Angélique Gougelet

2012-01-01

Full Text Available Canonical Wnt signalling, governed by its effector β-catenin, is known for a long time as playing an important role in development, tissue homeostasis, and cancer. In the liver, it was unravelled as both an oncogenic pathway involved in a subset of liver cancers and a physiological signalling identified as the “zonation-keeper” of the quiescent liver lobule. This duality has encouraged to explore the role of canonical Wnt in liver regeneration and liver-cell proliferation mainly using murine genetic models of β-catenin overactivation or inactivation. These studies definitely integrate Wnt signalling within the hepatic network driving regeneration and proliferation. We will review here the current knowledge concerning the mitogenic effect of Wnt, to switch on its specific role in the liver, which is quiescent but with a great capacity to regenerate. The duality of β-catenin signalling, associated both with liver quiescence and liver-cell proliferation, will be brought forward.

A Complex Interplay between Wnt/β-Catenin Signalling and the Cell Cycle in the Adult Liver.

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Gougelet, Angélique; Colnot, Sabine

2012-01-01

Canonical Wnt signalling, governed by its effector β-catenin, is known for a long time as playing an important role in development, tissue homeostasis, and cancer. In the liver, it was unravelled as both an oncogenic pathway involved in a subset of liver cancers and a physiological signalling identified as the "zonation-keeper" of the quiescent liver lobule. This duality has encouraged to explore the role of canonical Wnt in liver regeneration and liver-cell proliferation mainly using murine genetic models of β-catenin overactivation or inactivation. These studies definitely integrate Wnt signalling within the hepatic network driving regeneration and proliferation. We will review here the current knowledge concerning the mitogenic effect of Wnt, to switch on its specific role in the liver, which is quiescent but with a great capacity to regenerate. The duality of β-catenin signalling, associated both with liver quiescence and liver-cell proliferation, will be brought forward.

Effect of cadmium pretreatment on liver regeneration after partial hepatectomy in rats

International Nuclear Information System (INIS)

Margeli, A.; Theocharis, S.; Skaltsas, S.; Skopelitou, A.; Kittas, C.; Mykoniatis, M.; Varonos, D.

1994-01-01

In this study we examined the effect of cadmium pretreatment, administered 24 h before partial hepatectomy, on the liver regenerative process in rats, at different time intervals. The rate of 3 H thymidine incorporation into hepatic DNA and the activity of the enzyme thymidine kinase were used as indices of liver proliferative capacity. Thymidine kinase, the rate-determining enzyme of DNA biosynthesis, was suppressed during the first hours following partial hepatectomy in the liver of cadmium pretreated animals. DNA biosynthesis was also strongly decreased in cadmium pretreated animals, by delaying the first peak of liver regeneration, compared with the partially hepatectomized ones. Biochemical parameters, mitotic index and proliferating cell nuclear antigen staining were also coestimated. The above data suggest that cadmium pretreatment suppressed the hepatic regenerative process, probably due to the inhibition of thymidine kinase. (orig./MG)

Interleukin-1 inhibition facilitates recovery from liver injury and promotes regeneration of hepatocytes in alcoholic hepatitis in mice.

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Iracheta-Vellve, Arvin; Petrasek, Jan; Gyogyosi, Benedek; Bala, Shashi; Csak, Timea; Kodys, Karen; Szabo, Gyongyi

2017-07-01

Inflammation and impaired hepatocyte regeneration contribute to liver failure in alcoholic hepatitis (AH). Interleukin (IL)-1 is a key inflammatory cytokine in the pathobiology of AH. The role of IL-1 in liver regeneration in the recovery phase of alcohol-induced liver injury is unknown. In this study, we tested IL-1 receptor antagonist to block IL-1 signalling in a mouse model of acute-on-chronic liver injury on liver inflammation and hepatocyte regeneration in AH. We observed that inhibition of IL-1 signalling decreased liver inflammation and neutrophil infiltration, and resulted in enhanced regeneration of hepatocytes and increased rate of recovery from liver injury in AH. Our novel findings suggest that IL-1 drives sustained liver inflammation and impaired hepatocyte regeneration even after cessation of ethanol exposure. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Temporal mapping of CEBPA and CEBPB binding during liver regeneration reveals dynamic occupancy and specific regulatory codes for homeostatic and cell cycle gene batteries

DEFF Research Database (Denmark)

Jakobsen, Janus Schou; Waage, Johannes; Rapin, Nicolas

2013-01-01

quantified the genome-wide binding patterns of two key hepatocyte transcription factors, CEBPA and CEBPB (also known as C/EBPalpha and C/EBPbeta), at multiple time points during the highly dynamic process of liver regeneration elicited by partial hepatectomy in mouse. Combining these profiles with RNA...... polymerase II binding data, we find three temporal classes of transcription factor binding to be associated with distinct sets of regulated genes involved in the acute phase response, metabolic/homeostatic functions, or cell cycle progression. Moreover, we demonstrate a previously unrecognized early phase......IP experiments involving a panel of central transcription factors and/or by comparison to external ChIP-seq data. Our quantitative investigation not only provides in vivo evidence for the involvement of many new factors in liver regeneration but also points to similarities in the circuitries regulating self...

Cocktail of chemical compounds robustly promoting cell reprogramming protects liver against acute injury

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Yuewen Tang

2017-02-01

Full Text Available Abstract Tissue damage induces cells into reprogramming-like cellular state, which contributes to tissue regeneration. However, whether factors promoting the cell reprogramming favor tissue regeneration remains elusive. Here we identified combination of small chemical compounds including drug cocktails robustly promoting in vitro cell reprogramming. We then administrated the drug cocktails to mice with acute liver injuries induced by partial hepatectomy or toxic treatment. Our results demonstrated that the drug cocktails which promoted cell reprogramming in vitro improved liver regeneration and hepatic function in vivo after acute injuries. The underlying mechanism could be that expression of pluripotent genes activated after injury is further upregulated by drug cocktails. Thus our study offers proof-of-concept evidence that cocktail of clinical compounds improving cell reprogramming favors tissue recovery after acute damages, which is an attractive strategy for regenerative purpose.

TRANEXAMIC ACID ACTION ON LIVER REGENERATION AFTER PARTIAL HEPATECTOMY: EXPERIMENTAL MODEL IN RATS.

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Sobral, Felipe Antonio; Daga, Henrique; Rasera, Henrique Nogueira; Pinheiro, Matheus da Rocha; Cella, Igor Furlan; Morais, Igor Henrique; Marques, Luciana de Oliveira; Collaço, Luiz Martins

2016-01-01

Different lesions may affect the liver resulting in harmful stimuli. Some therapeutic procedures to treat those injuries depend on liver regeneration to increase functional capacity of this organ. Evaluate the effects of tranexamic acid on liver regeneration after partial hepatectomy in rats. 40 rats (Rattus norvegicus albinus, Rodentia mammalia) of Wistar-UP lineage were randomly divided into two groups named control (CT) and tranexamic acid (ATX), with 20 rats in each. Both groups were subdivided, according to liver regeneration time of 32 h or seven days after the rats had been operated. The organ regeneration was evaluated through weight and histology, stained with HE and PCNA. The average animal weight of ATX and CT 7 days groups before surgery were 411.2 g and 432.7 g, and 371.3 g and 392.9 g after the regeneration time, respectively. The average number of mitotic cells stained with HE for the ATX and CT 7 days groups were 33.7 and 32.6 mitosis, and 14.5 and 14.9 for the ATX and CT 32 h groups, respectively. When stained with proliferating cell nuclear antigen, the numbers of mitotic cells counted were 849.7 for the ATX 7 days, 301.8 for the CT 7 days groups, 814.2 for the ATX 32 hand 848.1 for the CT 32 h groups. Tranexamic acid was effective in liver regeneration, but in longer period after partial hepatectomy. Muitas são as injúrias que acometem o fígado e levam a estímulo lesivo. Alguns procedimentos terapêuticos para tratamento dessas lesões dependem da regeneração hepática para aumentar a sua capacidade funcional. Avaliar o efeito do ácido tranexâmico na regeneração hepática após hepatectomia parcial em ratos. Foram utilizados 40 ratos (Rattus norvegicus albinus, Rodentia mammalia) convencionais da linhagem Wistar-UP. Foram divididos aleatoriamente em dois grupos de 20: grupo controle (CT) e grupo ácido tranexâmico (ATX). Cada um deles foi divido em dois subgrupos para avaliar a regeneração hepática no tempo de 32 h e 7 dias do p

Liver bioengineering: Current status and future perspectives

Institute of Scientific and Technical Information of China (English)

Christopher Booth; Tom Soker; Pedro Baptista; Christina L Ross; Shay Soker; Umar Farooq; Robert J Stratta

2012-01-01

The present review aims to illustrate the strategies that are being implemented to regenerate or bioengineer livers for clinical purposes.There are two general pathways to liver bioengineering and regeneration.The first consists of creating a supporting scaffold,either synthetically or by decellularization of human or animal organs,and seeding cells on the scaffold,where they will mature either in bioreactors or in vivo.This strategy seems to offer the quickest route to clinical translation,as demonstrated by the development of liver organoids from rodent livers which were repopulated with organ specific cells of animal and/or human origin.Liver bioengineering has potential for transplantation and for toxicity testing during preclinical drug development.The second possibility is to induce liver regeneration of dead or resected tissue by manipulating cell pathways.In fact,it is well known that the liver has peculiar regenerative potential which allows hepatocyte hyperplasia after amputation of liver volume.Infusion of autologous bone marrow cells,which aids in liver regeneration,into patients was shown to be safe and to improve their clinical condition,but the specific cells responsible for liver regeneration have not yet been determined and the underlying mechanisms remain largely unknown.A complete understanding of the cell pathways and dynamics and of the functioning of liver stem cell niche is necessary for the clinical translation of regenerative medicine strategies.As well,it will be crucial to elucidate the mechanisms through which cells interact with the extracellular matrix,and how this latter supports and drives cell fate.

Enhancement of organ regeneration in animal models by a stem cell-stimulating plant mixture.

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Kiss, István; Tibold, Antal; Halmosi, Róbert; Bartha, Eva; Koltai, Katalin; Orsós, Zsuzsanna; Bujdosó, László; Ember, István

2010-06-01

Adult stem cells play an important role in the regeneration of damaged organs. Attempts have already been made to enhance stem cell production by cytokines, in order to increase the improvement of cardiac functions after myocardial infarction. In our present study we investigated the possibility whether instead of cytokine injection dietary stimulation of stem cell production accelerates the organ regeneration in animals. A dietary supplement, Olimpiq StemXCell (Crystal Institute Ltd., Eger, Hungary), containing plant extracts (previously proved to increase the number of circulating CD34(+) cells) was consumed in human equivalent doses by the experimental animals. In the first experiment carbon tetrachloride was applied to CBA/Ca mice, to induce liver damage, and liver weights between StemXCell-fed and control animals were compared 10 days after the treatment. In the second model experimental diabetes was induced in F344 rats by alloxan. Blood sugar levels were measured for 5 weeks in the control and StemXCell-fed groups. The third part of the study investigated the effect of StemXCell on cardiac functions. Eight weeks after causing a myocardial infarction in Wistar rats by isoproterenol, left ventricular ejection fraction was determined as a functional parameter of myocardial regeneration. In all three animal models StemXCell consumption statistically significantly improved the organ regeneration (relative liver weights, 4.78 +/-0.06 g/100 g vs. 4.97 +/- 0.07 g/100 g; blood sugar levels at week 5, 16 +/- 1.30 mmol/L vs. 10.2 +/- 0.92 mmol/L; ejection fraction, 57.5 +/- 2.23 vs. 68.2 +/- 4.94; controls vs. treated animals, respectively). Our study confirms the hypothesis that dietary enhancement of stem cell production may protect against organ injuries and helps in the regeneration.

mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

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Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

2015-02-01

Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration. © The Author (2015). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

Monocytes with angiogenic potential are selectively induced by liver resection and accumulate near the site of liver regeneration.

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Schauer, Dominic; Starlinger, Patrick; Zajc, Philipp; Alidzanovic, Lejla; Maier, Thomas; Buchberger, Elisabeth; Pop, Lorand; Gruenberger, Birgit; Gruenberger, Thomas; Brostjan, Christine

2014-10-30

Monocytes reportedly contribute to liver regeneration. Three subsets have been identified to date: classical, intermediate, non-classical monocytes. The intermediate population and a subtype expressing TIE2 (TEMs) were suggested to promote angiogenesis. In a clinical setting, we investigated which monocyte subsets are regulated after liver resection and correlate with postoperative liver function. In 38 patients monocyte subsets were evaluated in blood and subhepatic wound fluid by flow cytometry before and 1-3 days after resection of colorectal liver metastases. The monocyte-regulating cytokines macrophage colony stimulating factor (M-CSF), transforming growth factor beta 1 (TGFβ1), and angiopoietin 2 (ANG-2) were measured in patient plasma by ELISA. C-reactive protein (CRP) and liver function parameters were retrieved from routine hospital analyses. On post-operative day (POD) 1 blood monocytes shifted to significantly elevated levels of intermediate monocytes. In wound fluid, a delayed surge in intermediate monocytes was detected by POD 3. Furthermore, TEMs were highly enriched in wound fluid as compared to circulation. CRP and M-CSF levels were substantially increased in patient blood after surgery and correlated significantly with the frequency of intermediate monocytes. In addition, liver function parameters showed a significant association with intermediate monocyte levels on POD 3. The reportedly pro-angiogenic subsets of monocytes are selectively increased upon liver resection and accumulate next to the site of liver regeneration. As previously proposed by in vitro experiments, the release of CRP and M-CSF may trigger the induction of intermediate monocytes. The correlation with liver parameters points to a functional involvement of these monocyte populations in liver regeneration which warrants further investigation.

Retinoic Acid Signaling Mediates Hair Cell Regeneration by Repressing p27kip and sox2 in Supporting Cells.

Science.gov (United States)

Rubbini, Davide; Robert-Moreno, Àlex; Hoijman, Esteban; Alsina, Berta

2015-11-25

During development, otic sensory progenitors give rise to hair cells and supporting cells. In mammalian adults, differentiated and quiescent sensory cells are unable to generate new hair cells when these are lost due to various insults, leading to irreversible hearing loss. Retinoic acid (RA) has strong regenerative capacity in several organs, but its role in hair cell regeneration is unknown. Here, we use genetic and pharmacological inhibition to show that the RA pathway is required for hair cell regeneration in zebrafish. When regeneration is induced by laser ablation in the inner ear or by neomycin treatment in the lateral line, we observe rapid activation of several components of the RA pathway, with dynamics that position RA signaling upstream of other signaling pathways. We demonstrate that blockade of the RA pathway impairs cell proliferation of supporting cells in the inner ear and lateral line. Moreover, in neuromast, RA pathway regulates the transcription of p27(kip) and sox2 in supporting cells but not fgf3. Finally, genetic cell-lineage tracing using Kaede photoconversion demonstrates that de novo hair cells derive from FGF-active supporting cells. Our findings reveal that RA has a pivotal role in zebrafish hair cell regeneration by inducing supporting cell proliferation, and shed light on the underlying transcriptional mechanisms involved. This signaling pathway might be a promising approach for hearing recovery. Hair cells are the specialized mechanosensory cells of the inner ear that capture auditory and balance sensory input. Hair cells die after acoustic trauma, ototoxic drugs or aging diseases, leading to progressive hearing loss. Mammals, in contrast to zebrafish, lack the ability to regenerate hair cells. Here, we find that retinoic acid (RA) pathway is required for hair cell regeneration in vivo in the zebrafish inner ear and lateral line. RA pathway is activated very early upon hair cell loss, promotes cell proliferation of progenitor cells

Honey can repairing damage of liver tissue due to protein energy malnutrition through induction of endogenous stem cells.

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Prasetyo, R Heru; Hestianah, Eka Pramyrtha

2017-06-01

This study was to evaluate effect of honey in repairing damage of liver tissue due to energy protein malnutrition and in mobilization of endogenous stem cells. Male mice model of degenerative liver was obtained through food fasting but still have drinking water for 5 days. It caused energy protein malnutrition and damage of liver tissue. The administration of 50% (v/v) honey was performed for 10 consecutive days, while the positive control group was fasted and not given honey and the negative control not fasted and without honey. Observations of regeneration the liver tissue based on histologically examination, observation of Hsp70 expression, and homing signal based on vascular endothelial growth factor-1 (VEGF-1) expression using immunohistochemistry technique. Observation on expression of CD34 and CD45 as the marker of auto mobilization of hematopoietic stem cells using flow cytometry technique. There is regeneration of the liver tissue due to protein energy malnutrition, decrease of Hsp70 expression, increase of VEGF-1 expression, and high expression of CD34 and CD45. Honey can improve the liver tissue based on: (1) Mobilization of endogenous stem cells (CD34 and CD45); (2) Hsp70 and VEGF-1 expressions as regeneration marker of improvement, and (3) regeneration histologically of liver tissue.

Guided genetic screen to identify genes essential in the regeneration of hair cells and other tissues.

Science.gov (United States)

Pei, Wuhong; Xu, Lisha; Huang, Sunny C; Pettie, Kade; Idol, Jennifer; Rissone, Alberto; Jimenez, Erin; Sinclair, Jason W; Slevin, Claire; Varshney, Gaurav K; Jones, MaryPat; Carrington, Blake; Bishop, Kevin; Huang, Haigen; Sood, Raman; Lin, Shuo; Burgess, Shawn M

2018-01-01

Regenerative medicine holds great promise for both degenerative diseases and traumatic tissue injury which represent significant challenges to the health care system. Hearing loss, which affects hundreds of millions of people worldwide, is caused primarily by a permanent loss of the mechanosensory receptors of the inner ear known as hair cells. This failure to regenerate hair cells after loss is limited to mammals, while all other non-mammalian vertebrates tested were able to completely regenerate these mechanosensory receptors after injury. To understand the mechanism of hair cell regeneration and its association with regeneration of other tissues, we performed a guided mutagenesis screen using zebrafish lateral line hair cells as a screening platform to identify genes that are essential for hair cell regeneration, and further investigated how genes essential for hair cell regeneration were involved in the regeneration of other tissues. We created genetic mutations either by retroviral insertion or CRISPR/Cas9 approaches, and developed a high-throughput screening pipeline for analyzing hair cell development and regeneration. We screened 254 gene mutations and identified 7 genes specifically affecting hair cell regeneration. These hair cell regeneration genes fell into distinct and somewhat surprising functional categories. By examining the regeneration of caudal fin and liver, we found these hair cell regeneration genes often also affected other types of tissue regeneration. Therefore, our results demonstrate guided screening is an effective approach to discover regeneration candidates, and hair cell regeneration is associated with other tissue regeneration.

Bone morphogenetic protein-2 is a negative regulator of hepatocyte proliferation downregulated in the regenerating liver

NARCIS (Netherlands)

Xu, Cui-Ping; Ji, Wen-Min; van den Brink, Gijs R.; Peppelenbosch, Maikel P.

2006-01-01

To characterize the expression and dynamic changes of bone morphogenetic protein (BMP)-2 in hepatocytes in the regenerating liver in rats after partial hepatectomy (PH), and examine the effects of BMP-2 on proliferation of human Huh7 hepatoma cells. Fifty-four adult male Wistar rats were randomly

Bone morphogenetic protein-2 is a negative regulator of hepatocyte proliferation downregulated in the regenerating liver

NARCIS (Netherlands)

Xu, Cui-Ping; Ji, Wen-Min; van den Brink, Gijs R.; Peppelenbosch, Maikel P.

2006-01-01

AIM: To characterize the expression and dynamic changes of bone morphogenetic protein (BMP)-2 in hepatocytes in the regenerating liver in rats after partial hepatectomy (PH), and examine the effects of BMP-2 on proliferation of human Huh7 hepatoma cells. METHODS: Fifty-four adult male Wistar rats

Catheter-directed Intraportal Delivery of Endothelial Cell Therapy for Liver Regeneration: A Feasibility Study in a Large-Animal Model of Cirrhosis.

Science.gov (United States)

Lee, Kyungmouk Steve; Santagostino, Sara F; Li, David; Ramjit, Amit; Serrano, Kenneth; Ginsberg, Michael D; Ding, Bi-Sen; Rafii, Shahin; Madoff, David C

2017-10-01

Purpose To demonstrate the feasibility of imaging-guided catheter-directed delivery of endothelial cell therapy in a porcine model of cirrhosis for liver regeneration. Materials and Methods After approval from the institutional animal care and use committee, autologous liver endothelial cells were grown from core hepatic specimens from swine. Cirrhosis was induced in swine by means of transcatheter infusion of ethanol and iodized oil into the hepatic artery. Three weeks after induction of cirrhosis, the swine were randomly assigned to receive autologous cell therapy (endothelial cells, n = 4) or control treatment (phosphate-buffered saline, n = 4) by means of imaging-guided transhepatic intraportal catheterization. Fluorescence-activated cell sorting analysis was performed on biopsy samples 1 hour after therapy. Three weeks after intraportal delivery of endothelial cells, the swine were euthanized and the explanted liver underwent quantitative pathologic examination. Statistical analysis was performed with an unpaired t test by using unequal variance. Results Liver endothelial cells were successfully isolated, cultured, and expanded from eight 20-mm, 18-gauge hepatic core samples to 50 × 10 6 autologous cells per pig. Intraportal delivery of endothelial cell therapy or saline was technically successful in all eight swine, with no complications. Endothelial cells were present in the liver for a minimum of 1 hour after intraportal infusion. Swine treated with endothelial cell therapy showed mean levels of surrogate markers of hepatobiliary injury that were consistent with decreases in hepatic fibrosis and biliary ductal damage relative to the control animals, although statistical significance was not met in this pilot study: The mean percentage of positive pixels at Masson trichrome staining was 7.28% vs 5.57%, respectively (P = .20), the mean proliferation index with cytokeratin wide-spectrum was 2.55 vs 1.13 (P = .06), and the mean proliferation index with Ki67

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.

Transcriptome atlas of eight liver cell types uncovers effects of ...

Indian Academy of Sciences (India)

... types, and bioinformatic and systems biology approaches were employed to analyse the relationship between above genes and rat liver regeneration. The results showed that the urocanic acid (UA) was degraded from histidine in Kupffer cells, acts on Kupffer cells itself and dendritic cells to generate immune suppression ...

Natural Killer cells and liver fibrosis

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Frank eFasbender

2016-01-01

Full Text Available In the 40 years since the discovery of Natural Killer (NK cells it has been well established that these innate lymphocytes are important for early and effective immune responses against transformed cells and infections with different pathogens. In addition to these classical functions of NK cells, we now know that they are part of a larger family of innate lymphoid cells and that they can even mediate memory-like responses. Additionally, tissue resident NK cells with distinct phenotypical and functional characteristics have been identified. Here we focus on the phenotype of different NK cell subpopulations that can be found in the liver and summarize the current knowledge about the functional role of these cells with a special emphasis on liver fibrosis. NK cell cytotoxicity can contribute to liver damage in different forms of liver disease. However, NK cells can limit liver fibrosis by killing hepatic stellate cell-derived myofibroblasts, which play a key role in this pathogenic process. Therefore, liver NK cells need to be tightly regulated in order to balance these beneficial and pathological effects.

Regulator of G-protein signaling-5 is a marker of hepatic stellate cells and expression mediates response to liver injury.

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Arya J Bahrami

Full Text Available Liver fibrosis is mediated by hepatic stellate cells (HSCs, which respond to a variety of cytokine and growth factors to moderate the response to injury and create extracellular matrix at the site of injury. G-protein coupled receptor (GPCR-mediated signaling, via endothelin-1 (ET-1 and angiotensin II (AngII, increases HSC contraction, migration and fibrogenesis. Regulator of G-protein signaling-5 (RGS5, an inhibitor of vasoactive GPCR agonists, functions to control GPCR-mediated contraction and hypertrophy in pericytes and smooth muscle cells (SMCs. Therefore we hypothesized that RGS5 controls GPCR signaling in activated HSCs in the context of liver injury. In this study, we localize RGS5 to the HSCs and demonstrate that Rgs5 expression is regulated during carbon tetrachloride (CCl4-induced acute and chronic liver injury in Rgs5LacZ/LacZ reporter mice. Furthermore, CCl4 treated RGS5-null mice develop increased hepatocyte damage and fibrosis in response to CCl4 and have increased expression of markers of HSC activation. Knockdown of Rgs5 enhances ET-1-mediated signaling in HSCs in vitro. Taken together, we demonstrate that RGS5 is a critical regulator of GPCR signaling in HSCs and regulates HSC activation and fibrogenesis in liver injury.

Generation and characterization of rat liver stem cell lines and their engraftment in a rat model of liver failure

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Kuijk, Ewart W.; Rasmussen, Shauna; Blokzijl, Francis; Huch, Meritxell; Gehart, Helmuth; Toonen, Pim; Begthel, Harry; Clevers, Hans; Geurts, Aron M.; Cuppen, Edwin

2016-01-01

The rat is an important model for liver regeneration. However, there is no in vitro culture system that can capture the massive proliferation that can be observed after partial hepatectomy in rats. We here describe the generation of rat liver stem cell lines. Rat liver stem cells, which grow as cystic organoids, were characterized by high expression of the stem cell marker Lgr5, by the expression of liver progenitor and duct markers, and by low expression of hepatocyte markers, oval cell markers, and stellate cell markers. Prolonged cultures of rat liver organoids depended on high levels of WNT-signalling and the inhibition of BMP-signaling. Upon transplantation of clonal lines to a Fah−/− Il2rg−/− rat model of liver failure, the rat liver stem cells engrafted into the host liver where they differentiated into areas with FAH and Albumin positive hepatocytes. Rat liver stem cell lines hold potential as consistent reliable cell sources for pharmacological, toxicological or metabolic studies. In addition, rat liver stem cell lines may contribute to the development of regenerative medicine in liver disease. To our knowledge, the here described liver stem cell lines represent the first organoid culture system in the rat. PMID:26915950

Modeling Dynamics and Function of Bone Marrow Cells in Mouse Liver Regeneration

NARCIS (Netherlands)

Pedone, Elisa; Olteanu, Vlad-Aris; Marucci, Lucia; Muñoz-Martin, Maria Isabel; Youssef, Sameh A; de Bruin, Alain; Cosma, Maria Pia

2017-01-01

In rodents and humans, the liver can efficiently restore its mass after hepatectomy. This is largely attributed to the proliferation and cell cycle re-entry of hepatocytes. On the other hand, bone marrow cells (BMCs) migrate into the liver after resection. Here, we find that a block of BMC

Signaling factors in stem cell-mediated repair of infarcted myocardium

NARCIS (Netherlands)

Vandervelde, S; van Luyn, MJA; Tio, RA; Harmsen, MC

Myocardial infarction leads to scar formation and subsequent reduced cardiac performance. The ultimate therapy after myocardial infarction would pursue stem cell-based regeneration. The aim of stem cell-mediated cardiac repair embodies restoration of cardiac function by regeneration of healthy

Honey can repairing damage of liver tissue due to protein energy malnutrition through induction of endogenous stem cells

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R. Heru Prasetyo

2017-06-01

Full Text Available Aim: This study was to evaluate effect of honey in repairing damage of liver tissue due to energy protein malnutrition and in mobilization of endogenous stem cells. Materials and Methods: Male mice model of degenerative liver was obtained through food fasting but still have drinking water for 5 days. It caused energy protein malnutrition and damage of liver tissue. The administration of 50% (v/v honey was performed for 10 consecutive days, while the positive control group was fasted and not given honey and the negative control not fasted and without honey. Observations of regeneration the liver tissue based on histologically examination, observation of Hsp70 expression, and homing signal based on vascular endothelial growth factor-1 (VEGF-1 expression using immunohistochemistry technique. Observation on expression of CD34 and CD45 as the marker of auto mobilization of hematopoietic stem cells using flow cytometry technique. Results: There is regeneration of the liver tissue due to protein energy malnutrition, decrease of Hsp70 expression, increase of VEGF-1 expression, and high expression of CD34 and CD45. Conclusion: Honey can improve the liver tissue based on: (1 Mobilization of endogenous stem cells (CD34 and CD45; (2 Hsp70 and VEGF-1 expressions as regeneration marker of improvement, and (3 regeneration histologically of liver tissue.

LSD1 is Required for Hair Cell Regeneration in Zebrafish.

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He, Yingzi; Tang, Dongmei; Cai, Chengfu; Chai, Renjie; Li, Huawei

2016-05-01

Lysine-specific demethylase 1 (LSD1/KDM1A) plays an important role in complex cellular processes such as differentiation, proliferation, apoptosis, and cell cycle progression. It has recently been demonstrated that during development, downregulation of LSD1 inhibits cell proliferation, modulates the expression of cell cycle regulators, and reduces hair cell formation in the zebrafish lateral line, which suggests that LSD1-mediated epigenetic regulation plays a key role in the development of hair cells. However, the role of LSD1 in hair cell regeneration after hair cell loss remains poorly understood. Here, we demonstrate the effect of LSD1 on hair cell regeneration following neomycin-induced hair cell loss. We show that the LSD1 inhibitor trans-2-phenylcyclopropylamine (2-PCPA) significantly decreases the regeneration of hair cells in zebrafish after neomycin damage. In addition, immunofluorescent staining demonstrates that 2-PCPA administration suppresses supporting cell proliferation and alters cell cycle progression. Finally, in situ hybridization shows that 2-PCPA significantly downregulates the expression of genes related to Wnt/β-catenin and Fgf activation. Altogether, our data suggest that downregulation of LSD1 significantly decreases hair cell regeneration after neomycin-induced hair cell loss through inactivation of the Wnt/β-catenin and Fgf signaling pathways. Thus, LSD1 plays a critical role in hair cell regeneration and might represent a novel biomarker and potential therapeutic approach for the treatment of hearing loss.

Nuclear medicine study of regeneration process of the liver after partial hepatectomy in normal rats

International Nuclear Information System (INIS)

Nomura, Yasushi

1990-01-01

To evaluate regeneration of the liver in rats after partial hepatectomy based on Higgins' and Anderson's method, the present study reports using the morphological and radionuclide technique. The adult Wistar rats over 8 weeks of age were prepared in this study and were injected intravenously with either 99m Tc-N-(2,6 dimethylphenylcarbamoylmethyl) iminodiacetic acid ( 99m Tc-HIDA) or 99m Tc-phytate. Using Fishback equation, the ratio of wet weight liver regeneration was approximately 80% at 14 days after partial hepatectomy. On pathology, the microscopical findings were as follows: congestion and hepatocytes swelling on day 1; diffuse fat deposition and nuclear division on day 2; decreased hepatocytes swelling, fat deposition, and regular alignment of the hepatocytes on day 5; appearance of normal liver on day 7-14. The uptake and excretion ratio of the hepatocytes using 99m Tc-HIDA as a radionuclide technique recovered to the value prior to partial hepatectomy on day 3, and also the hepatic accumulation coefficient of Kupffer cells using 99m Tc-phytate recoverd on day 4. In conclusion, it was found that the functional recovery employed 3-4 days after partial hepatectomy. The present study using two radiopharmaceuticals describes that the radionuclide techniques can facilitate to evaluate the manifest pathological alterations of hepatocytes and Kupffer cells after partial hepatectomy. (author)

Kupffer Cells in the Liver

Science.gov (United States)

Dixon, Laura J.; Barnes, Mark; Tang, Hui; Pritchard, Michele T.; Nagy, Laura E.

2016-01-01

Kupffer cells are a critical component of the mononuclear phagocytic system and are central to both the hepatic and systemic response to pathogens. Kupffer cells are reemerging as critical mediators of both liver injury and repair. Kupffer cells exhibit a tremendous plasticity; depending on the local metabolic and immune environment, then can express a range of polarized phenotypes, from the proinflammatory M1 phenotype to the alternative/M2 phenotype. Multiple M2 phenotypes can be distinguished, each involved in the resolution of inflammation and wound healing. Here, we have provided an update on recent research that has contributed to the developing delineation of the contribution of Kupffer cells to different types of liver injury, with an emphasis on alcoholic and nonalcoholic liver diseases. These recent advances in our understanding of Kupffer cell function and regulation will likely provide new insights into the potential for therapeutic manipulation of Kupffer cells to promote the resolution of inflammation and enhance wound healing in liver disease. PMID:23720329

Adenovirus-mediated transfer of hepatocyte growth factor gene to human dental pulp stem cells under good manufacturing practice improves their potential for periodontal regeneration in swine.

Science.gov (United States)

Cao, Yu; Liu, Zhenhai; Xie, Yilin; Hu, Jingchao; Wang, Hua; Fan, Zhipeng; Zhang, Chunmei; Wang, Jingsong; Wu, Chu-Tse; Wang, Songlin

2015-12-15

Periodontitis is one of the most widespread infectious diseases in humans. We previously promoted significant periodontal tissue regeneration in swine models with the transplantation of autologous periodontal ligament stem cells (PDLSCs) and PDLSC sheet. We also promoted periodontal tissue regeneration in a rat model with a local injection of allogeneic bone marrow mesenchymal stem cells. The purpose of the present study is to investigate the roles of the hepatocyte growth factor (HGF) and human dental pulp stem cells (DPSCs) in periodontal tissue regeneration in swine. In the present study, we transferred an adenovirus that carried HGF gene into human DPSCs (HGF-hDPSCs) under good manufacturing practice (GMP) conditions. These cells were then transplanted into a swine model for periodontal regeneration. Twenty miniature pigs were used to generate periodontitis with bone defect of 5 mm in width, 7 mm in length, and 3 mm in depth. After 12 weeks, clinical, radiological, quantitative and histological assessment of regenerated periodontal tissues was performed to compare periodontal regeneration in swine treated with cell implantation. Our study showed that injecting HGF-hDPSCs into this large animal model could significantly improve periodontal bone regeneration and soft tissue healing. A hDPSC or HGF-hDPSC sheet showed superior periodontal tissue regeneration compared to the injection of dissociated cells. However, the sheets required surgical placement; thus, they were suitable for surgically-managed periodontitis treatments. The adenovirus-mediated transfer of the HGF gene markedly decreased hDPSC apoptosis in a hypoxic environment or in serum-free medium, and it increased blood vessel regeneration. This study indicated that HGF-hDPSCs produced under GMP conditions significantly improved periodontal bone regeneration in swine; thus, this method represents a potential clinical application for periodontal regeneration.

Inhibition of type I NKT cells by retinoids or following sulfatide-mediated activation of type II NKT cells attenuates alcoholic liver disease

Science.gov (United States)

Maricic, Igor; Sheng, Huiming; Marrero, Idania; Seki, Ehikiro; Kisseleva, Tatiana; Chaturvedi, Som; Molle, Natasha; Mathews, K. Stephanie; Gao, Bin; Kumar, Vipin

2015-01-01

Innate immune mechanisms leading to liver injury following chronic alcohol ingestion are poorly understood. Natural killer T (NKT) cells, enriched in the liver and comprised of at least two distinct subsets, type I and type II, recognize different lipid antigens presented by CD1d molecules. We have investigated whether differential activation of NKT cell subsets orchestrates inflammatory events leading to alcoholic liver disease (ALD). We found that following chronic plus binge feeding of Lieber-DeCarli liquid diet in male C57BL/6 mice, type I but not type II NKT cells are activated leading to recruitment of inflammatory Gr-1highCD11b+ cells into liver. A central finding is that liver injury following alcohol feeding is dependent upon type I NKT cells. Thus liver injury is significantly inhibited in Jα18−/− mice deficient in type I NKT cells as well as following their inactivation by sulfatide-mediated activation of type II NKT cells. Furthermore we have identified a novel pathway involving all-trans retinoic acid (ATRA) and its receptor RARγ signaling that inhibits type I NKT cells and consequently ALD. A semi-quantitative PCR analysis of hepatic gene expression of some of the key proinflammatory molecules shared in human disease indicated that their upregulation in ALD is dependent upon type I NKT cells. Conclusion Type I but not type II NKT cells become activated following alcohol feeding. Type I NKT cells-induced inflammation and neutrophil recruitment results in liver tissue damage while type II NKT cells protect from injury in ALD. Inhibition of type I NKT cells by retinoids or by sulfatide prevents ALD. Since the CD1d pathway is highly conserved between mice and humans, NKT cell subsets might be targeted for potential therapeutic intervention in ALD. PMID:25477000

Splenectomy after partial hepatectomy accelerates liver regeneration in mice by promoting tight junction formation via polarity protein Par 3-aPKC.

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Liu, Guoxing; Xie, Chengzhi; Fang, Yu; Qian, Ke; Liu, Qiang; Liu, Gao; Cao, Zhenyu; Du, Huihui; Fu, Jie; Xu, Xundi

2018-01-01

Several experimental studies have demonstrated that removal of the spleen accelerates liver regeneration after partial hepatectomy. While the mechanism of splenectomy promotes liver regeneration by the improvement of the formation of tight junction and the establishment of hepatocyte polarity is still unknown. We analyzed the cytokines, genes and proteins expression between 70% partial hepatectomy mice (PHx) and simultaneous 70% partial hepatectomy and splenectomy mice (PHs) at predetermined timed points. Compared with the PHx group mice, splenectomy accelerated hepatocyte proliferation in PHs group. The expression of Zonula occludens-1 (ZO-1) indicated that splenectomy promotes the formation of tight junction during liver regeneration. TNF-α, IL-6, HGF, TSP-1 and TGF-β1 were essential factors for the formation of tight junction and the establishment of hepatocytes polarity in liver regeneration. After splenectomy, Partitioning defective 3 homolog (Par 3) and atypical protein kinase C (aPKC) regulate hepatocyte localization and junctional structures in regeneration liver. Our data suggest that the time course expression of TNF-α, IL-6, HGF, TSP-1, and TGF-β1 and the change of platelets take part in liver regeneration. Combination with splenectomy accelerates liver regeneration by improvement of the tight junction formation which may help to establish hepatocyte polarity via Par 3-aPKC. This may provide a clue for us that splenectomy could accelerate liver regeneration after partial hepatectomy of hepatocellular carcinoma and living donor liver transplantation. Copyright © 2017 Elsevier Inc. All rights reserved.

Fibrogenic Cell Plasticity Blunts Tissue Regeneration and Aggravates Muscular Dystrophy

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Patrizia Pessina

2015-06-01

Full Text Available Preservation of cell identity is necessary for homeostasis of most adult tissues. This process is challenged every time a tissue undergoes regeneration after stress or injury. In the lethal Duchenne muscular dystrophy (DMD, skeletal muscle regenerative capacity declines gradually as fibrosis increases. Using genetically engineered tracing mice, we demonstrate that, in dystrophic muscle, specialized cells of muscular, endothelial, and hematopoietic origins gain plasticity toward a fibrogenic fate via a TGFβ-mediated pathway. This results in loss of cellular identity and normal function, with deleterious consequences for regeneration. Furthermore, this fibrogenic process involves acquisition of a mesenchymal progenitor multipotent status, illustrating a link between fibrogenesis and gain of progenitor cell functions. As this plasticity also was observed in DMD patients, we propose that mesenchymal transitions impair regeneration and worsen diseases with a fibrotic component.

Hepatic progenitors for liver disease: current position

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Alice Conigliaro

2010-02-01

Full Text Available Alice Conigliaro1, David A Brenner2, Tatiana Kisseleva21University “La Sapienza”, Dipartimento di Biotecnologie Cellulari ed Ematologia Policlinico Umberto I, V Clinica Medica, Rome, Italy; 2Department of Medicine, University of California, San Diego, La Jolla, CA, USAAbstract: Liver regeneration restores the original functionality of hepatocytes and cholangiocytes in response to injury. It is regulated on several levels, with different cellular populations contributing to this process, eg, hepatocytes, liver precursor cells, intrahepatic stem cells. In response to injury, mature hepatocytes have the capability to proliferate and give rise to new hepatocytes and cholangiocytes. Meanwhile, liver precursor cells (oval cells have become the most recognized bipotential precursor cells in the damaged liver. They rapidly proliferate, change their cellular composition, and differentiate into hepatocytes and cholangiocytes to compensate for the cellular loss and maintain liver homeostasis. There is a growing body of evidence that oval cells originate from the intrahepatic stem cell(s, which in turn give(s rise to epithelial, including oval cells, and/or other hepatic cells of nonepithelial origin. Since there is a close relationship between the liver and hematopoiesis, bone marrow derived cells can also contribute to liver regeneration by the fusion of myeloid cells with damaged hepatocytes, or differentiation of mesenchymal stem cells into hepatocyte-like cells. The current review discusses the contribution of different cells to liver regeneration and their characteristics.Keywords: hepatic progenitor, liver disease, liver precursor cells, oval cells, hepatocytes, intrahepatic stem cells, cholangiocytes

Heterogeneous fates and dynamic rearrangement of regenerative epidermis-derived cells during zebrafish fin regeneration.

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Shibata, Eri; Ando, Kazunori; Murase, Emiko; Kawakami, Atsushi

2018-04-13

The regenerative epidermis (RE) is a specialized tissue that plays an essential role in tissue regeneration. However, the fate of the RE during and after regeneration is unknown. In this study, we performed Cre- loxP -mediated cell fate tracking and revealed the fates of a major population of the RE cells that express fibronectin 1b ( fn1b ) during zebrafish fin regeneration. Our study showed that these RE cells are mainly recruited from the inter-ray epidermis, and that they follow heterogeneous cell fates. Early recruited cells contribute to initial wound healing and soon disappear by apoptosis, while the later recruited cells contribute to the regenerated epidermis. Intriguingly, many of these cells are also expelled from the regenerated tissue by a dynamic caudal movement of the epidermis over time, and in turn the loss of epidermal cells is replenished by a global self-replication of basal and suprabasal cells in fin. De-differentiation of non-basal epidermal cells into the basal epidermal cells did not occur during regeneration. Overall, our study reveals the heterogeneous fates of RE cells and a dynamic rearrangement of the epidermis during and after regeneration. © 2018. Published by The Company of Biologists Ltd.

Osteoblast Production by Reserved Progenitor Cells in Zebrafish Bone Regeneration and Maintenance.

Science.gov (United States)

Ando, Kazunori; Shibata, Eri; Hans, Stefan; Brand, Michael; Kawakami, Atsushi

2017-12-04

Mammals cannot re-form heavily damaged bones as in large fracture gaps, whereas zebrafish efficiently regenerate bones even after amputation of appendages. However, the source of osteoblasts that mediate appendage regeneration is controversial. Several studies in zebrafish have shown that osteoblasts are generated by dedifferentiation of existing osteoblasts at injured sites, but other observations suggest that de novo production of osteoblasts also occurs. In this study, we found from cell-lineage tracing and ablation experiments that a group of cells reserved in niches serves as osteoblast progenitor cells (OPCs) and has a significant role in fin ray regeneration. Besides regeneration, OPCs also supply osteoblasts for normal bone maintenance. We further showed that OPCs are derived from embryonic somites, as is the case with embryonic osteoblasts, and are replenished from mesenchymal precursors in adult zebrafish. Our findings reveal that reserved progenitors are a significant and complementary source of osteoblasts for zebrafish bone regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Regenerative response in the pig liver remnant varies with the degree of resection and rise in portal pressure

DEFF Research Database (Denmark)

Mortensen, Kim Erlend; Conley, Lene Nagsrrup; Hedegaard, Jakob

2008-01-01

After parenchymal loss, the liver regenerates restoring normal mass and metabolic function. Prevailing theories on triggering events leading to regeneration include humoral, metabolic, and flow-mediated mechanisms, the latter emphasizing the importance of shear stress mediated nitric oxide...... in the high portal pressure resection group to have functions related primarily to apoptosis, nitric oxide metabolism and oxidative stress, whereas differentially expressed genes in the low portal pressure resection group potentially regulate the cell cycle. Common to both groups was the upregulation of genes...... regulating inflammation, transport, cell proliferation, development, and protein metabolism. Also common to both groups was both up- and downregulation of genes regulating cell-cell signaling, signal transduction, cell adhesion, and translation. Genes regulating the metabolism of lipids, hormones, amines...

[Hepatic cell transplantation: a new therapy in liver diseases].

Science.gov (United States)

Pareja, Eugenia; Cortés, Miriam; Martínez, Amparo; Vila, Juan José; López, Rafael; Montalvá, Eva; Calzado, Angeles; Mir, José

2010-07-01

Liver transplantation has been remarkably effective in the treatment in patients with end-stage liver disease. However, disparity between solid-organ supply and increased demand is the greatest limitation, resulting in longer waiting times and increase in mortality of transplant recipients. This situation creates the need to seek alternatives to orthotopic liver transplantation.Hepatocyte transplantation or liver cell transplantation has been proposed as the best method to support patients. The procedure consists of transplanting individual cells to a recipient organ in sufficient quantity to survive and restore the function. The capacity of hepatic regeneration is the biological basis of hepatocyte transplantation. This therapeutic option is an experimental procedure in some patients with inborn errors of metabolism, fulminant hepatic failure and acute and chronic liver failure, as a bridge to orthotopic liver transplantation. In the Hospital La Fe of Valencia, we performed the first hepatocyte transplantation in Spain creating a new research work on transplant program. Copyright 2009 AEC. Published by Elsevier Espana. All rights reserved.

Chronic inflammation-elicited liver progenitor cell conversion to liver cancer stem cell with clinical significance.

Science.gov (United States)

Li, Xiao-Feng; Chen, Cheng; Xiang, Dai-Min; Qu, Le; Sun, Wen; Lu, Xin-Yuan; Zhou, Teng-Fei; Chen, Shu-Zhen; Ning, Bei-Fang; Cheng, Zhuo; Xia, Ming-Yang; Shen, Wei-Feng; Yang, Wen; Wen, Wen; Lee, Terence Kin Wah; Cong, Wen-Ming; Wang, Hong-Yang; Ding, Jin

2017-12-01

The substantial heterogeneity and hierarchical organization in liver cancer support the theory of liver cancer stem cells (LCSCs). However, the relationship between chronic hepatic inflammation and LCSC generation remains obscure. Here, we observed a close correlation between aggravated inflammation and liver progenitor cell (LPC) propagation in the cirrhotic liver of rats exposed to diethylnitrosamine. LPCs isolated from the rat cirrhotic liver initiated subcutaneous liver cancers in nonobese diabetic/severe combined immunodeficient mice, suggesting the malignant transformation of LPCs toward LCSCs. Interestingly, depletion of Kupffer cells in vivo attenuated the LCSC properties of transformed LPCs and suppressed cytokeratin 19/Oval cell 6-positive tumor occurrence. Conversely, LPCs cocultured with macrophages exhibited enhanced LCSC properties. We further demonstrated that macrophage-secreted tumor necrosis factor-α triggered chromosomal instability in LPCs through the deregulation of ubiquitin D and checkpoint kinase 2 and enhanced the self-renewal of LPCs through the tumor necrosis factor receptor 1/Src/signal transducer and activator of transcription 3 pathway, which synergistically contributed to the conversion of LPCs to LCSCs. Clinical investigation revealed that cytokeratin 19/Oval cell 6-positive liver cancer patients displayed a worse prognosis and exhibited superior response to sorafenib treatment. Our results not only clarify the cellular and molecular mechanisms underlying the inflammation-mediated LCSC generation but also provide a molecular classification for the individualized treatment of liver cancer. (Hepatology 2017;66:1934-1951). © 2017 by the American Association for the Study of Liver Diseases.

Downregulation of IL6 Targeted MiR-376b May Contribute to a Positive IL6 Feedback Loop During Early Liver Regeneration in Mice

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Shan Lu

2015-08-01

Full Text Available Background/Aims: MicroRNAs (miRNAs are a group of endogenous, small, noncoding RNAs implicated in a variety of biological processes, including cell proliferation, apoptosis, differentiation and metabolism. The present study aims to explore the potential role and molecular mechanism of miR-376b during the early phase of liver regeneration. Methods: MiRNA profiling microarrays were used to assess the changes in miRNA expression. For functional analysis, cell proliferation, apoptosis assays, real time quantitative PCR and westernblot analysis were performed. Results: The comprehensive miRNA expression profiling assays on regenerating liver tissues 4 h after partial hepatectomy (PH showed that three miRNAs (miR-127, miR-376b and miR-494 located in the Dlk1-Gtl2 miRNA cluster were significantly downregulated. In vitro functional studies demonstrated that high-level interleukin 6 (IL6 inhibited the expression of miR-376b, and miR-376b mimics treatment decreased cell proliferation and increased apoptosis. Further target analysis showed that miR-376b reduced the mRNA and protein expression levels of NF-kappa-B inhibitor zeta (NFKBIZ and signal transducers and transcription activators 3 (STAT3. Additionally, IL6-induced miR-376b downregulation would, in turn, increase the expression of IL-6 possibly via a feedback loop involving NFKBIZ or/and STAT3. Conclusion: During the early phase of liver regeneration, miR-376b expression was significantly decreased. Our findings reveal that a regulatory circuitry between miR-376b and IL-6 may exist, which trigger the initiation of liver regeneration.

Dual effects of adenovirus-mediated thrombopoietin gene transfer on hepatic oval cell proliferation and platelet counts

International Nuclear Information System (INIS)

Ichiba, Miho; Shimomura, Takashi; Murai, Rie; Hashiguchi, Koichi; Saeki, Toshiya; Yoshida, Yoko; Kanbe, Takamasa; Tanabe, Naotada; Tsuchiya, Hiroyuki; Miura, Norimasa; Tajima, Fumihito; Kurimasa, Akihiro; Hamada, Hirofumi; Shiota, Goshi

2005-01-01

Thrombopoietin (TPO) is the growth factor for megakaryocytes and platelets, however, it also acts as a potent regulator of stem cell proliferation. To examine the significance of TPO expression in proliferation of hepatic oval cells, the effect of adenovirus-mediated TPO gene transfer into livers of the Solt-Farber model, which mimics the condition where liver regeneration is impaired, was examined. Hepatic TPO mRNA peaked its expression at 2 days after gene transduction and then gradually decreased. The peripheral platelet number began to increase at 4 days (P < 0.05) and reached its plateau at 9 days (P < 0.01). Oval cells expressed c-Mpl, a receptor for TPO as well as immature hematopoietic and hepatocytic surface markers such as CD34 and AFP. The proliferating cell nuclear antigen-positive oval cells in rats into which adenovirus-TPO gene was transferred at 7 and 9 days were significantly greater than those in adenovirus-LacZ gene transferred (P < 0.05, each), and the total numbers of oval cells in the adenovirus-TPO gene transferred at 9 and 13 days were also significantly greater than those in adenovirus-LacZ gene transferred (P < 0.05, each). Expression of SCF protein was increased at 4, 7, and 9 days by TPO gene administration and that of c-Kit was increased at 4 and 7 days. These data suggest that adenovirus-mediated TPO gene transfer stimulated oval cell proliferation in liver as well as increasing peripheral platelet counts, emphasizing the significance of the TPO/c-Mpl system in proliferation of hepatic oval cells

Production of BMP4 by endothelial cells is crucial for endogenous thymic regeneration

Science.gov (United States)

Wertheimer, Tobias; Velardi, Enrico; Tsai, Jennifer; Cooper, Kirsten; Xiao, Shiyun; Kloss, Christopher C.; Ottmüller, Katja J.; Mokhtari, Zeinab; Brede, Christian; deRoos, Paul; Kinsella, Sinéad; Palikuqi, Brisa; Ginsberg, Michael; Young, Lauren F.; Kreines, Fabiana; Lieberman, Sophia R.; Lazrak, Amina; Guo, Peipei; Malard, Florent; Smith, Odette M.; Shono, Yusuke; Jenq, Robert R.; Hanash, Alan M.; Nolan, Daniel J.; Butler, Jason M.; Beilhack, Andreas; Manley, Nancy R.; Rafii, Shahin; Dudakov, Jarrod A; van den Brink, Marcel RM

2018-01-01

The thymus is extremely sensitive to damage but also has a remarkable ability to repair itself. However, the mechanisms underlying this endogenous regeneration remain poorly understood and this capacity diminishes considerably with age. Here we show that thymic endothelial cells (ECs) comprise a critical pathway of regeneration, via their production of BMP4. ECs increased their production of BMP4 after thymic damage, and abrogating BMP4 signalling or production by either pharmacologic or genetic inhibition impaired thymic repair. EC-derived BMP4 acted on thymic epithelial cells (TECs) to increase their expression of Foxn1, a key transcription factor involved in TEC development, maintenance and regeneration; and its downstream targets such as Dll4, itself a key mediator of thymocyte development and regeneration. These studies demonstrate the importance of the BMP4 pathway in endogenous tissue regeneration and offer a potential clinical approach to enhance T cell immunity. PMID:29330161

Biomimetic extracellular matrix mediated somatic stem cell differentiation: applications in dental pulp tissue regeneration

Science.gov (United States)

Ravindran, Sriram; George, Anne

2015-01-01

Dental caries is one of the most widely prevalent infectious diseases in the world. It affects more than half of the world's population. The current treatment for necrotic dental pulp tissue arising from dental caries is root canal therapy. This treatment results in loss of tooth sensitivity and vitality making it prone for secondary infections. Over the past decade, several tissue-engineering approaches have attempted regeneration of the dental pulp tissue. Although several studies have highlighted the potential of dental stem cells, none have transitioned into a clinical setting owing to limited availability of dental stem cells and the need for growth factor delivery systems. Our strategy is to utilize the intact ECM of pulp cells to drive lineage specific differentiation of bone marrow derived mesenchymal stem cells. From a clinical perspective, pulp ECM scaffolds can be generated using cell lines and patient specific somatic stem cells can be used for regeneration. Our published results have shown the feasibility of using pulp ECM scaffolds for odontogenic differentiation of non-dental mesenchymal cells. This focused review discusses the issues surrounding dental pulp tissue regeneration and the potential of our strategy to overcome these issues. PMID:25954205

HEXIM1 controls satellite cell expansion after injury to regulate skeletal muscle regeneration

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Hong, Peng; Chen, Kang; Huang, Bihui; Liu, Min; Cui, Miao; Rozenberg, Inna; Chaqour, Brahim; Pan, Xiaoyue; Barton, Elisabeth R.; Jiang, Xian-Cheng; Siddiqui, M.A.Q.

2012-01-01

The native capacity of adult skeletal muscles to regenerate is vital to the recovery from physical injuries and dystrophic diseases. Currently, the development of therapeutic interventions has been hindered by the complex regulatory network underlying the process of muscle regeneration. Using a mouse model of skeletal muscle regeneration after injury, we identified hexamethylene bisacetamide inducible 1 (HEXIM1, also referred to as CLP-1), the inhibitory component of the positive transcription elongation factor b (P-TEFb) complex, as a pivotal regulator of skeletal muscle regeneration. Hexim1-haplodeficient muscles exhibited greater mass and preserved function compared with those of WT muscles after injury, as a result of enhanced expansion of satellite cells. Transplanted Hexim1-haplodeficient satellite cells expanded and improved muscle regeneration more effectively than WT satellite cells. Conversely, HEXIM1 overexpression restrained satellite cell proliferation and impeded muscle regeneration. Mechanistically, dissociation of HEXIM1 from P-TEFb and subsequent activation of P-TEFb are required for satellite cell proliferation and the prevention of early myogenic differentiation. These findings suggest a crucial role for the HEXIM1/P-TEFb pathway in the regulation of satellite cell–mediated muscle regeneration and identify HEXIM1 as a potential therapeutic target for degenerative muscular diseases. PMID:23023707

High circulatory leptin mediated NOX-2-peroxynitrite-miR21 axis activate mesangial cells and promotes renal inflammatory pathology in nonalcoholic fatty liver disease

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Firas Alhasson

2018-07-01

Full Text Available High circulatory insulin and leptin followed by underlying inflammation are often ascribed to the ectopic manifestations in non-alcoholic fatty liver disease (NAFLD but the exact molecular pathways remain unclear. We have shown previously that CYP2E1-mediated oxidative stress and circulating leptin in NAFLD is associated with renal disease severity. Extending the studies, we hypothesized that high circulatory leptin in NAFLD causes renal mesangial cell activation and tubular inflammation via a NOX2 dependent pathway that upregulates proinflammatory miR21. High-fat diet (60% kcal was used to induce fatty liver phenotype with parallel insulin and leptin resistance. The kidneys were probed for mesangial cell activation and tubular inflammation that showed accelerated NASH phenotype and oxidative stress in the liver. Results showed that NAFLD kidneys had significant increases in α-SMA, a marker of mesangial cell activation, miR21 levels, tyrosine nitration and renal inflammation while they were significantly decreased in leptin and p47 phox knockout mice. Micro RNA21 knockout mice showed decreased tubular immunotoxicity and proinflammatory mediator release. Mechanistically, use of NOX2 siRNA or apocynin,phenyl boronic acid (FBA, DMPO or miR21 antagomir inhibited leptin primed-miR21-mediated mesangial cell activation in vitro suggesting a direct role of leptin-mediated NOX-2 in miR21-mediated mesangial cell activation. Finally, JAK-STAT inhibitor completely abrogated the mesangial cell activation in leptin-primed cells suggesting that leptin signaling in the mesangial cells depended on the JAK-STAT pathway. Taken together the study reports a novel mechanistic pathway of leptin-mediated renal inflammation that is dependent on NOX-2-miR21 axis in ectopic manifestations underlying NAFLD-induced co-morbidities. Keywords: Leptin, NOX-2, NADPH, Mesangial cells, miR21, Oxidative stress, NAFLD, JAK/STAT, siRNA

The emerging role of mast cells in liver disease.

Science.gov (United States)

Jarido, Veronica; Kennedy, Lindsey; Hargrove, Laura; Demieville, Jennifer; Thomson, Joanne; Stephenson, Kristen; Francis, Heather

2017-08-01

The depth of our knowledge regarding mast cells has widened exponentially in the last 20 years. Once thought to be only important for allergy-mediated events, mast cells are now recognized to be important regulators of a number of pathological processes. The revelation that mast cells can influence organs, tissues, and cells has increased interest in mast cell research during liver disease. The purpose of this review is to refresh the reader's knowledge of the development, type, and location of mast cells and to review recent work that demonstrates the role of hepatic mast cells during diseased states. This review focuses primarily on liver diseases and mast cells during autoimmune disease, hepatitis, fatty liver disease, liver cancer, and aging in the liver. Overall, these studies demonstrate the potential role of mast cells in disease progression.

Hepatocyte transplantation and advancements in alternative cell sources for liver-based regenerative medicine.

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Lee, Charlotte A; Sinha, Siddharth; Fitzpatrick, Emer; Dhawan, Anil

2018-06-01

Human hepatocyte transplantation has been actively perused as an alternative to liver replacement for acute liver failure and liver-based metabolic defects. Current challenges in this field include a limited cell source, reduced cell viability following cryopreservation and poor engraftment of cells into the recipient liver with consequent limited life span. As a result, alternative stem cell sources such as pluripotent stem cells, fibroblasts, hepatic progenitor cells, amniotic epithelial cells and mesenchymal stem/stromal cells (MSCs) can be used to generate induced hepatocyte like cells (HLC) with each technique exhibiting advantages and disadvantages. HLCs may have comparable function to primary human hepatocytes and could offer patient-specific treatment. However, long-term functionality of transplanted HLCs and the potential oncogenic risks of using stem cells have yet to be established. The immunomodulatory effects of MSCs are promising, and multiple clinical trials are investigating their effect in cirrhosis and acute liver failure. Here, we review the current status of hepatocyte transplantation, alternative cell sources to primary human hepatocytes and their potential in liver regeneration. We also describe recent clinical trials using hepatocytes derived from stem cells and their role in improving the phenotype of several liver diseases.

HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver.

Science.gov (United States)

Ding, Bi-Sen; Liu, Catherine H; Sun, Yue; Chen, Yutian; Swendeman, Steven L; Jung, Bongnam; Chavez, Deebly; Cao, Zhongwei; Christoffersen, Christina; Nielsen, Lars Bo; Schwab, Susan R; Rafii, Shahin; Hla, Timothy

2016-12-22

Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 (S1P 1 ) by its natural ligand bound to HDL (HDL-S1P) induces liver regeneration and curtails fibrosis. In mice lacking HDL-S1P, liver regeneration after partial hepatectomy was impeded and associated with aberrant vascular remodeling, thrombosis and peri-sinusoidal fibrosis. Notably, this "maladaptive repair" phenotype was recapitulated in mice that lack S1P 1 in the endothelium. Reciprocally, enhanced plasma levels of HDL-S1P or administration of SEW2871, a pharmacological agonist specific for S1P 1 enhanced regeneration of metabolically functional vasculature and alleviated fibrosis in mouse chronic injury and cholestasis models. This study shows that natural and pharmacological ligands modulate endothelial S1P 1 to stimulate liver regeneration and inhibit fibrosis, suggesting that activation of this pathway may be a novel therapeutic strategy for liver fibrosis.

CD13 Promotes Mesenchymal Stem Cell-mediated regeneration of ischemic muscle

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M. Mamunur eRahman

2014-01-01

Full Text Available Mesenchymal stem cells (MSCs are multipotent, tissue-resident cells that can facilitate tissue regeneration and thus show great promise as potential therapeutic agents. Functional MSCs have been isolated and characterized from a wide array of adult tissues and are universally identified by the shared expression of a core panel of MSCs markers. One of these markers is the multifunctional cell surface peptidase CD13 that has been shown to be expressed on human and murine MSCs from many tissues. To investigate whether this universal expression indicates a functional role for CD13 in MSC biology we isolated, expanded and characterized MSCs from bone marrow of wild type (WT and CD13KO mice. Characterization of these cells demonstrated that both WT and CD13KO MSCs expressed the full complement of MSC markers (CD29, CD44, CD49e, CD105, Sca1, showed comparable proliferation rates and were capable of differentiating toward the adipogenic and osteogenic lineages. However, MSCs lacking CD13 were unable to differentiate into vascular cells, consistent with our previous characterization of CD13 as an angiogenic regulator. Compared to WT MSCs, adhesion and migration on various extracellular matrices of CD13KO MSCs were significantly impaired, which correlated with decreased phospho-FAK levels and cytoskeletal alterations. Crosslinking human MSCs with activating CD13 antibodies increased cell adhesion to endothelial monolayers and induced FAK activation in a time dependent manner. In agreement with these in vitro data, intramuscular injection of CD13KO MSCs in a model of severe ischemic limb injury resulted in significantly poorer perfusion, decreased ambulation, increased necrosis and impaired vascularization compared to those receiving WT MSCs. This study suggests that CD13 regulates FAK activation to promote MSC adhesion and migration, thus contributing to MSC-mediated tissue repair. CD13 may present a viable target to enhance the efficacy of mesenchymal

Cell migration during heart regeneration in zebrafish.

Science.gov (United States)

Tahara, Naoyuki; Brush, Michael; Kawakami, Yasuhiko

2016-07-01

Zebrafish possess the remarkable ability to regenerate injured hearts as adults, which contrasts the very limited ability in mammals. Although very limited, mammalian hearts do in fact have measurable levels of cardiomyocyte regeneration. Therefore, elucidating mechanisms of zebrafish heart regeneration would provide information of naturally occurring regeneration to potentially apply to mammalian studies, in addition to addressing this biologically interesting phenomenon in itself. Studies over the past 13 years have identified processes and mechanisms of heart regeneration in zebrafish. After heart injury, pre-existing cardiomyocytes dedifferentiate, enter the cell cycle, and repair the injured myocardium. This process requires interaction with epicardial cells, endocardial cells, and vascular endothelial cells. Epicardial cells envelope the heart, while endocardial cells make up the inner lining of the heart. They provide paracrine signals to cardiomyocytes to regenerate the injured myocardium, which is vascularized during heart regeneration. In addition, accumulating results suggest that local migration of these major cardiac cell types have roles in heart regeneration. In this review, we summarize the characteristics of various heart injury methods used in the research community and regeneration of the major cardiac cell types. Then, we discuss local migration of these cardiac cell types and immune cells during heart regeneration. Developmental Dynamics 245:774-787, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Advances in ultrasound-targeted microbubble-mediated gene therapy for liver fibrosis.

Science.gov (United States)

Huang, Cuiyuan; Zhang, Hong; Bai, Ruidan

2017-07-01

Hepatic fibrosis develops as a wound-healing scar in response to acute and chronic liver inflammation and can lead to cirrhosis in patients with chronic hepatitis B and C. The condition arises due to increased synthesis and reduced degradation of extracellular matrix (ECM) and is a common pathological sequela of chronic liver disease. Excessive deposition of ECM in the liver causes liver dysfunction, ascites, and eventually upper gastrointestinal bleeding as well as a series of complications. However, fibrosis can be reversed before developing into cirrhosis and has thus been the subject of extensive researches particularly at the gene level. Currently, therapeutic genes are imported into the damaged liver to delay or prevent the development of liver fibrosis by regulating the expression of exogenous genes. One technique of gene delivery uses ultrasound targeting of microbubbles combined with therapeutic genes where the time and intensity of the ultrasound can control the release process. Ultrasound irradiation of microbubbles in the vicinity of cells changes the permeability of the cell membrane by its cavitation effect and enhances gene transfection. In this paper, recent progress in the field is reviewed with emphasis on the following aspects: the types of ultrasound microbubbles, the construction of an ultrasound-mediated gene delivery system, the mechanism of ultrasound microbubble-mediated gene transfer and the application of ultrasound microbubbles in the treatment of liver fibrosis.

Advances in ultrasound-targeted microbubble-mediated gene therapy for liver fibrosis

Directory of Open Access Journals (Sweden)

Cuiyuan Huang

2017-07-01

Full Text Available Hepatic fibrosis develops as a wound-healing scar in response to acute and chronic liver inflammation and can lead to cirrhosis in patients with chronic hepatitis B and C. The condition arises due to increased synthesis and reduced degradation of extracellular matrix (ECM and is a common pathological sequela of chronic liver disease. Excessive deposition of ECM in the liver causes liver dysfunction, ascites, and eventually upper gastrointestinal bleeding as well as a series of complications. However, fibrosis can be reversed before developing into cirrhosis and has thus been the subject of extensive researches particularly at the gene level. Currently, therapeutic genes are imported into the damaged liver to delay or prevent the development of liver fibrosis by regulating the expression of exogenous genes. One technique of gene delivery uses ultrasound targeting of microbubbles combined with therapeutic genes where the time and intensity of the ultrasound can control the release process. Ultrasound irradiation of microbubbles in the vicinity of cells changes the permeability of the cell membrane by its cavitation effect and enhances gene transfection. In this paper, recent progress in the field is reviewed with emphasis on the following aspects: the types of ultrasound microbubbles, the construction of an ultrasound-mediated gene delivery system, the mechanism of ultrasound microbubble–mediated gene transfer and the application of ultrasound microbubbles in the treatment of liver fibrosis.

The effect of apple (Malus Domestica juice on the damage of mice liver cells due to paracetamol treatment

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Anthony Hartanto

2009-07-01

Full Text Available The liver is an important organ for body metabolism process. Liver disease is one of serious health problems in developing countries including Indonesia. Liver damage is caused by viral infection, toxic agent exposure (medications, alcohol, hormonal disturbance, neoplasm and autoimmune diseases. The use of high dose paracetamol to reduce pain also leads to liver damage. Apple (Malus domestica juice is a natural anti oxidant agent. This laboratory experimental study was performed to discover the effect of giving apple juice on damaged cell regeneration due to the use of paracetamol. The study was performed in 21 male mice from Swiss-Webster strain that were divided into group I, II, and III. Group, I served as control while group II received 1 mg/ml paracetamol dose for 5 days and Group III received 1 mg/ml paracetamol for 5 days and 1 ml of apple juice on the 5th to 10th day. The observation of the mice liver cells was conducted using a light microscope with 400x magnification to get the number of necrotic liver cells per view field. The results of this study showed a difference in the number of necrotic liver cells between Group II and III. ANOVA statistical test ( = 0.05 concluded that apple juice significantly helps regeneration process in damaged liver cells caused by paracetamol.

Inhibition of oxidative stress-elicited AKT activation facilitates PPARγ agonist-mediated inhibition of stem cell character and tumor growth of liver cancer cells.

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Lanlan Liu

Full Text Available Emerging evidence suggests that tumor-initiating cells (TICs are the most malignant cell subpopulation in tumors because of their resistance to chemotherapy or radiation treatment. Targeting TICs may be a key innovation for cancer treatment. In this study, we found that PPARγ agonists inhibited the cancer stem cell-like phenotype and attenuated tumor growth of human hepatocellular carcinoma (HCC cells. Reactive oxygen species (ROS initiated by NOX2 upregulation were partially responsible for the inhibitory effects mediated by PPARγ agonists. However, PPARγ agonist-mediated ROS production significantly activated AKT, which in turn promoted TIC survival by limiting ROS generation. Inhibition of AKT, by either pharmacological inhibitors or AKT siRNA, significantly enhanced PPARγ agonist-mediated inhibition of cell proliferation and stem cell-like properties in HCC cells. Importantly, in nude mice inoculated with HCC Huh7 cells, we demonstrated a synergistic inhibitory effect of the PPARγ agonist rosiglitazone and the AKT inhibitor triciribine on tumor growth. In conclusion, we observed a negative feedback loop between oxidative stress and AKT hyperactivation in PPARγ agonist-mediated suppressive effects on HCCs. Combinatory application of an AKT inhibitor and a PPARγ agonist may provide a new strategy for inhibition of stem cell-like properties in HCCs and treatment of liver cancer.

Liver regeneration after partial hepatectomy in rat is more impaired in a steatotic liver induced by dietary fructose compared to dietary fat

International Nuclear Information System (INIS)

Tanoue, Shirou; Uto, Hirofumi; Kumamoto, Ryo; Arima, Shiho; Hashimoto, Shinichi; Nasu, Yuichiro; Takami, Yoichiro; Moriuchi, Akihiro; Sakiyama, Toshio; Oketani, Makoto; Ido, Akio; Tsubouchi, Hirohito

2011-01-01

Highlights: → Hepatic steatosis in rats fed a high fructose diet was less severe than that in rats fed a high fat diet. → Liver regeneration was more impaired in rats fed a high fructose diet than in rats fed a high fat diet. → Dysregulation of genes associated with metabolism may contribute to impairment of liver regeneration. → Regulation of the TGF-β1 level after partial hepatectomy may be impaired in rats fed a high fructose diet. -- Abstract: Hepatic steatosis (HS) has a negative effect on liver regeneration, but different pathophysiologies of HS may lead to different outcomes. Male Sprague-Dawley rats were fed a high fructose (66% fructose; H-fruc), high fat (54% fat; H-fat), or control chow diet for 4 weeks. Based on hepatic triglyceride content and oil red O staining, HS developed in the H-fruc group, but was less severe compared to the H-fat group. Hepatic mRNA expression levels of fatty acid synthase and fructokinase were increased and those of carnitine palmitoyltransferase-1 and peroxisome proliferator-activated receptor-α were decreased in the H-fruc group compared to the H-fat group. Liver regeneration after 70% partial hepatectomy (PHx) was evaluated by measuring the increase in postoperative liver mass and PCNA-positive hepatocytes, and was impaired in the H-fruc group compared to the H-fat and control groups on days 3 and 7. Serum levels of tumor necrosis factor-α, interleukin-6 and hepatocyte growth factor did not change significantly after PHx. In contrast, serum TGF-β1 levels were slightly but significantly lower in the control group on day 1 and in the H-fat group on day 3 compared to the level in each group on day 0, and then gradually increased. However, the serum TGF-β1 level did not change after PHx in the H-fruc group. These results indicate that impairment of liver regeneration after PHx in HS is related to the cause, rather than the degree, of steatosis. This difference may result from altered metabolic gene expression

Liver regeneration after partial hepatectomy in rat is more impaired in a steatotic liver induced by dietary fructose compared to dietary fat

Energy Technology Data Exchange (ETDEWEB)

Tanoue, Shirou [Department of Digestive and Lifestyle-Related Diseases, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Uto, Hirofumi, E-mail: hirouto@m2.kufm.kagoshima-u.ac.jp [Department of Digestive and Lifestyle-Related Diseases, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima (Japan); Kumamoto, Ryo; Arima, Shiho; Hashimoto, Shinichi; Nasu, Yuichiro; Takami, Yoichiro; Moriuchi, Akihiro; Sakiyama, Toshio; Oketani, Makoto; Ido, Akio; Tsubouchi, Hirohito [Department of Digestive and Lifestyle-Related Diseases, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima (Japan)

2011-04-01

Highlights: {yields} Hepatic steatosis in rats fed a high fructose diet was less severe than that in rats fed a high fat diet. {yields} Liver regeneration was more impaired in rats fed a high fructose diet than in rats fed a high fat diet. {yields} Dysregulation of genes associated with metabolism may contribute to impairment of liver regeneration. {yields} Regulation of the TGF-{beta}1 level after partial hepatectomy may be impaired in rats fed a high fructose diet. -- Abstract: Hepatic steatosis (HS) has a negative effect on liver regeneration, but different pathophysiologies of HS may lead to different outcomes. Male Sprague-Dawley rats were fed a high fructose (66% fructose; H-fruc), high fat (54% fat; H-fat), or control chow diet for 4 weeks. Based on hepatic triglyceride content and oil red O staining, HS developed in the H-fruc group, but was less severe compared to the H-fat group. Hepatic mRNA expression levels of fatty acid synthase and fructokinase were increased and those of carnitine palmitoyltransferase-1 and peroxisome proliferator-activated receptor-{alpha} were decreased in the H-fruc group compared to the H-fat group. Liver regeneration after 70% partial hepatectomy (PHx) was evaluated by measuring the increase in postoperative liver mass and PCNA-positive hepatocytes, and was impaired in the H-fruc group compared to the H-fat and control groups on days 3 and 7. Serum levels of tumor necrosis factor-{alpha}, interleukin-6 and hepatocyte growth factor did not change significantly after PHx. In contrast, serum TGF-{beta}1 levels were slightly but significantly lower in the control group on day 1 and in the H-fat group on day 3 compared to the level in each group on day 0, and then gradually increased. However, the serum TGF-{beta}1 level did not change after PHx in the H-fruc group. These results indicate that impairment of liver regeneration after PHx in HS is related to the cause, rather than the degree, of steatosis. This difference may result

Memory NK cells: why do they reside in the liver?

OpenAIRE

Jiang, Xiaojun; Chen, Yonglin; Peng, Hui; Tian, Zhigang

2013-01-01

Immune memory is the hallmark of adaptive immunity. However, recent studies have shown that natural killer (NK) cells, key components of the innate immune system, also mediate memory responses in mice and humans. Strikingly, memory NK cells were liver-resident in some models, raising the question as to whether the liver is a special organ for the acquisition of NK cell memory. Here, we review the characteristics of NK cell memory by summarizing recent progress and discuss how the liver may ge...

Transient HIF2A inhibition promotes satellite cell proliferation and muscle regeneration.

Science.gov (United States)

Xie, Liwei; Yin, Amelia; Nichenko, Anna S; Beedle, Aaron M; Call, Jarrod A; Yin, Hang

2018-03-13

The remarkable regeneration capability of skeletal muscle depends on coordinated proliferation and differentiation of satellite cells. The self-renewal of satellite cells is critical for long-term maintenance of muscle regeneration potential. Hypoxia profoundly affects the proliferation, differentiation, and self-renewal of cultured myoblasts. However, the physiological relevance of hypoxia and hypoxia signaling in satellite cells in vivo remains largely unknown. Here, we report that satellite cells are in an intrinsic hypoxic state in vivo and express hypoxia-inducible factor 2A (HIF2A). HIF2A promotes the stemness and long-term homeostatic maintenance of satellite cells by maintaining the quiescence, increasing the self-renewal and blocking the myogenic differentiation of satellite cells. HIF2A stabilization in satellite cells cultured under normoxia augmented their engraftment potential in regenerative muscle. Reversely, HIF2A ablation led to the depletion of satellite cells and the consequent regenerative failure in the long-term. In contrast, transient pharmacological inhibition of HIF2A accelerated muscle regeneration by increasing satellite cell proliferation and differentiation. Mechanistically, HIF2A induces the quiescence/self-renewal of satellite cells by binding the promoter of Spry1 gene and activating Spry1 expression. These findings suggest that HIF2A is a pivotal mediator of hypoxia signaling in satellite cells and may be therapeutically targeted to improve muscle regeneration.

RACK1-mediated translation control promotes liver fibrogenesis

Energy Technology Data Exchange (ETDEWEB)

Liu, Min; Peng, Peike; Wang, Jiajun [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Wang, Lan; Duan, Fangfang [Institute of Biomedical Science, Fudan University, Shanghai 200032 (China); Jia, Dongwei, E-mail: jiadongwei@fudan.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Ruan, Yuanyuan, E-mail: yuanyuanruan@fudan.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Gu, Jianxin [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Institute of Biomedical Science, Fudan University, Shanghai 200032 (China)

2015-07-31

Activation of quiescent hepatic stellate cells (HSCs) is the central event of liver fibrosis. The translational machinery is an optimized molecular network that affects cellular homoeostasis and diseases, whereas the role of protein translation in HSCs activation and liver fibrosis is little defined. Our previous report suggests that up-regulation of receptor for activated C-kinase 1(RACK1) in HSCs is critical for liver fibrogenesis. In this study, we found that RACK1 promoted macrophage conditioned medium (MCM)-induced assembly of eIF4F and phosphorylation of eIF4E in primary HSCs. RACK1 enhanced the translation and expression of pro-fibrogenic factors collagen 1α1, snail and cyclin E1 induced by MCM. Administration of PP242 or knock-down of eIF4E suppressed RACK1-stimulated collagen 1α1 production, proliferation and migration in primary HSCs. In addition, depletion of eIF4E attenuated thioacetamide (TAA)-induced liver fibrosis in vivo. Our data suggest that RACK1-mediated stimulation of cap-dependent translation plays crucial roles in HSCs activation and liver fibrogenesis, and targeting translation initiation could be a promising strategy for the treatment of liver fibrosis. - Highlights: • RACK1 induces the assembly of eIF4F and phosphorylation of eIF4E in primary HSCs. • RACK1 stimulates the translation of collagen 1α1, snail and cyclin E1 in HSCs. • RACK1 promotes HSCs activation via cap-mediated translation. • Depletion of eIF4E suppresses liver fibrogenesis in vivo.

RACK1-mediated translation control promotes liver fibrogenesis

International Nuclear Information System (INIS)

Liu, Min; Peng, Peike; Wang, Jiajun; Wang, Lan; Duan, Fangfang; Jia, Dongwei; Ruan, Yuanyuan; Gu, Jianxin

2015-01-01

Activation of quiescent hepatic stellate cells (HSCs) is the central event of liver fibrosis. The translational machinery is an optimized molecular network that affects cellular homoeostasis and diseases, whereas the role of protein translation in HSCs activation and liver fibrosis is little defined. Our previous report suggests that up-regulation of receptor for activated C-kinase 1(RACK1) in HSCs is critical for liver fibrogenesis. In this study, we found that RACK1 promoted macrophage conditioned medium (MCM)-induced assembly of eIF4F and phosphorylation of eIF4E in primary HSCs. RACK1 enhanced the translation and expression of pro-fibrogenic factors collagen 1α1, snail and cyclin E1 induced by MCM. Administration of PP242 or knock-down of eIF4E suppressed RACK1-stimulated collagen 1α1 production, proliferation and migration in primary HSCs. In addition, depletion of eIF4E attenuated thioacetamide (TAA)-induced liver fibrosis in vivo. Our data suggest that RACK1-mediated stimulation of cap-dependent translation plays crucial roles in HSCs activation and liver fibrogenesis, and targeting translation initiation could be a promising strategy for the treatment of liver fibrosis. - Highlights: • RACK1 induces the assembly of eIF4F and phosphorylation of eIF4E in primary HSCs. • RACK1 stimulates the translation of collagen 1α1, snail and cyclin E1 in HSCs. • RACK1 promotes HSCs activation via cap-mediated translation. • Depletion of eIF4E suppresses liver fibrogenesis in vivo

Human amnion epithelial cells expressing HLA-G as novel cell-based treatment for liver disease.

Science.gov (United States)

Strom, Stephen C; Gramignoli, Roberto

2016-09-01

Despite routine liver transplantation and supporting medical therapies, thousands of patients currently wait for an organ and there is an unmet need for more refined and widely available regenerative strategies to treat liver diseases. Cell transplants attempt to maximize the potential for repair and/or regeneration in liver and other organs. Over 40years of laboratory pre-clinical research and 25years of clinical procedures have shown that certain liver diseases can be treated by the infusion of isolated cells (hepatocyte transplant). However, like organ transplants, hepatocyte transplant suffers from a paucity of tissues useful for cell production. Alternative sources have been investigated, yet with limited success. The tumorigenic potential of pluripotent stem cells together with their primitive level of hepatic differentiation, have limited the use of stem cell populations. Stem cell sources from human placenta, and the amnion tissue in particular are receiving renewed interest in the field of regenerative medicine. Unlike pluripotent stem cells, human amnion epithelial (AE) cells are easily available without ethical or religious concerns; they do not express telomerase and are not immortal or tumorigenic when transplanted. In addition, AE cells have been reported to express genes normally expressed in mature liver, when transplanted into the liver. Moreover, because of the possibility of an immune-privileged status related to their expression of HLA-G, it might be possible to transplant human AE cells without immunosuppression of the recipient. Copyright © 2016. Published by Elsevier Inc.

Germline Transgenic Methods for Tracking Cells and Testing Gene Function during Regeneration in the Axolotl

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Khattak, Shahryar; Schuez, Maritta; Richter, Tobias; Knapp, Dunja; Haigo, Saori L.; Sandoval-Guzmán, Tatiana; Hradlikova, Kristyna; Duemmler, Annett; Kerney, Ryan; Tanaka, Elly M.

2013-01-01

The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cell-cycle inhibitor p16INK4a, which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible. PMID:24052945

Regulation of Injury-Induced Ovarian Regeneration by Activation of Oogonial Stem Cells.

Science.gov (United States)

Erler, Piril; Sweeney, Alexandra; Monaghan, James R

2017-01-01

Some animals have the ability to generate large numbers of oocytes throughout life. This raises the question whether persistent adult germline stem cell populations drive continuous oogenesis and whether they are capable of mounting a regenerative response after injury. Here we demonstrate the presence of adult oogonial stem cells (OSCs) in the adult axolotl salamander ovary and show that ovarian injury induces OSC activation and functional regeneration of the ovaries to reproductive capability. Cells that have morphological similarities to germ cells were identified in the developing and adult ovaries via histological analysis. Genes involved in germ cell maintenance including Vasa, Oct4, Sox2, Nanog, Bmp15, Piwil1, Piwil2, Dazl, and Lhx8 were expressed in the presumptive OSCs. Colocalization of Vasa protein with H3 mitotic marker showed that both oogonial and spermatogonial adult stem cells were mitotically active. Providing evidence of stemness and viability of adult OSCs, enhanced green fluorescent protein (EGFP) adult OSCs grafted into white juvenile host gonads gave rise to EGFP OSCs, and oocytes. Last, the axolotl ovaries completely regenerated after partial ovariectomy injury. During regeneration, OSC activation resulted in rapid differentiation into new oocytes, which was demonstrated by Vasa + /BrdU + coexpression. Furthermore, follicle cell proliferation promoted follicle maturation during ovarian regeneration. Overall, these results show that adult oogenesis occurs via proliferation of endogenous OSCs in a tetrapod and mediates ovarian regeneration. This study lays the foundations to elucidate mechanisms of ovarian regeneration that will assist regenerative medicine in treating premature ovarian failure and reduced fertility. Stem Cells 2017;35:236-247. © 2016 AlphaMed Press.

The Role of Butylidenephthalide in Targeting Microenvironment Contributes to the Ameliorate of Liver Fibrosis

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Hong-Meng eChuang

2016-04-01

Full Text Available The treatment of liver fibrosis has clinical limitations because of its multiple etiologies, such as epithelial–mesenchymal transition (EMT promotion, cell regeneration and remodeling dysfunction, inflammatory cell activation, and scar tissue deposition. These factors might be considered as a new target for the fibrotic microenvironment, leading to increased fibrogenesis and liver fibrosis. Here, we investigate a small molecule named butylidenephthalide (BP and its multiple effects on liver fibrosis treatment. Thioacetamide was used in vivo to induce chronic liver fibrosis. BP was administered orally in rats for a period of 2 weeks and 4 weeks, which resulted in a significantly reduced fibrosis score (p<0.05 and (p<0.001, respectively. The inflammatory reaction of macrophage infiltration were reduced in the administration of BP, which led to the decrease in the transaminase levels. Moreover, we also found liver functions recovering (due to the increased serum albumin and reduced prothrombin time where liver cells regenerated, which can be seen in the increase of Ki-67 on Oval cell. In addition, the fibrotic scar was also reduced, along with the expression of matrix metalloprotease by hepatic stellate cell. Furthermore, regarding the mechanism/study of EMT reduced by BP, the knockdown of BMP-7, which could reduce α-SMA expression, was mediated by the regulation of TGF-β, which implies its major role on EMT. Finally, in the in vivo study, BP treatment of liver fibrosis was reduced by Bmp7 knockdown in zebrafish, suggesting that BP leads to the reduction of liver fibrosis, which also depends on BMP-7 induction. These results suggest that BP had multiple targets for treating liver fibrosis in the following ways: reduction of EMT, decreasing inflammatory reaction, and liver cell proliferation. This multiple targets approach provided a new mechanism to treat liver injury and fibrosis.

DNMT1 is a Required Genomic Regulator for Murine Liver Histogenesis and Regeneration

DEFF Research Database (Denmark)

Kaji, Kosuke; Factor, Valentina M; Andersen, Jesper B

2016-01-01

as transcriptome and methylation profiling. Regenerative growth was induced by partial hepatectomy and exposure to CCl4 . The impact of Dnmt1 knockdown was also analyzed in hepatic progenitor cell (HPC) lines; proliferation, apoptosis, DNA damage and sphere formation were assessed. Dnmt1 loss in postnatal...... hepatocytes caused global hypomethylation, enhanced DNA damage response and initiated a senescence state causing a progressive inability to maintain tissue homeostasis and proliferate in response to injury. The liver regenerated via activation and repopulation from progenitors due to lineage......-dependent differences in Alb-Cre expression, providing a basis for selection of less mature and therefore less damaged HPC progeny. Consistently, an efficient knockdown of Dnmt1 in cultured HPCs caused severe DNA damage, cell cycle arrest, senescence and cell death. Mx1-Cre-driven deletion of Dnmt1 in adult quiescent...

Memory NK cells: why do they reside in the liver?

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Jiang, Xiaojun; Chen, Yonglin; Peng, Hui; Tian, Zhigang

2013-05-01

Immune memory is the hallmark of adaptive immunity. However, recent studies have shown that natural killer (NK) cells, key components of the innate immune system, also mediate memory responses in mice and humans. Strikingly, memory NK cells were liver-resident in some models, raising the question as to whether the liver is a special organ for the acquisition of NK cell memory. Here, we review the characteristics of NK cell memory by summarizing recent progress and discuss how the liver may generate both the initiation and the recall phase of memory. We propose that the liver may have unique precursors for memory NK cells, which are developmentally distinct from NK cells derived from bone marrow.

Bone Marrow-Derived Mesenchymal Stem Cells Attenuate Immune-Mediated Liver Injury and Compromise Virus Control During Acute Hepatitis B Virus Infection in Mice.

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Qu, Mengmeng; Yuan, Xu; Liu, Dan; Ma, Yuhong; Zhu, Jun; Cui, Jun; Yu, Mengxue; Li, Changyong; Guo, Deyin

2017-06-01

Mesenchymal stem cells (MSCs) have been used as therapeutic tools not only for their ability to differentiate toward different cells, but also for their unique immunomodulatory properties. However, it is still unknown how MSCs may affect immunity during hepatitis B virus (HBV) infection. This study was designed to explore the effect of bone marrow-derived MSCs (BM-MSCs) on hepatic natural killer (NK) cells in a mouse model of acute HBV infection. Mice were injected with 1 × 10 6 BM-MSCs, which stained with chloromethyl derivatives of fluorescein diacetate fluorescent probe, 24 h before hydrodynamic injection of viral DNA (pHBV1.3) through the tail vein. In vivo imaging system revealed that BM-MSCs were accumulated in the injured liver, and they attenuated immune-mediated liver injury during HBV infection, as shown by lower alanine aminotransferase levels, reduced proinflammatory cytokine production, and decreased inflammatory cell infiltration in the liver. Importantly, administration of BM-MSCs restrained the increased expression of natural-killer group 2, member D (NKG2D), an important receptor required for NK cell activation in the liver from HBV-infected mice. BM-MSCs also reduced NKG2D expression on NK cells and suppressed the cytotoxicity of NK cells in vitro. Furthermore, BM-MSC-derived transforming growth factor-β1 suppressed NKG2D expression on NK cells. As a consequence, BM-MSC treatment enhanced HBV gene expression and replication in vivo. These results demonstrate that adoptive transfer of BM-MSCs influences innate immunity and limits immune-mediated liver injury during acute HBV infection by suppressing NK cell activity. Meanwhile, the effect of BM-MSCs on prolonging virus clearance needs to be considered in the future.

Stem cell regenerative potential combined with nanotechnology and tissue engineering for myocardial regeneration.

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Calin, Manuela; Stan, Daniela; Simion, Viorel

2013-07-01

The stem cell-based therapy for post-infarction myocardial regeneration has been introduced more than a decade ago, but the functional improvement obtained is limited due to the poor retention and short survival rate of transplanted cells into the damaged myocardium. More recently, the emerging nanotechnology concepts for advanced diagnostics and therapy provide promising opportunities of using stem cells for myocardial regeneration. In this paper will be provided an overview of the use of nanotechnology approaches in stem cell research for: 1) cell labeling to track the distribution of stem cells after transplantation, 2) nanoparticle-mediated gene delivery to stem cells to promote their homing, engraftment, survival and differentiation in the ischemic myocardium and 3) obtaining of bio-inspired materials to provide suitable myocardial scaffolds for delivery of stem cells or stem cell-derived factors.

PHP14 regulates hepatic stellate cells migration in liver fibrosis via mediating TGF-β1 signaling to PI3Kγ/AKT/Rac1 pathway.

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Xu, Anjian; Li, Yanmeng; Zhao, Wenshan; Hou, Fei; Li, Xiaojin; Sun, Lan; Chen, Wei; Yang, Aiting; Wu, Shanna; Zhang, Bei; Yao, Jingyi; Wang, Huan; Huang, Jian

2018-02-01

Hepatic fibrosis is characterized by the activation of hepatic stellate cells (HSCs). Migration of the activated HSCs to the site of injury is one of the key characteristics during the wound healing process. We have previously demonstrated that 14 kDa phosphohistidine phosphatase (PHP14) is involved in migration and lamellipodia formation of HSCs. However, the role of PHP14 in liver fibrosis remains unknown. In this study, we first assessed PHP14 expression and distribution in liver fibrotic tissues using western blot, immunohistochemistry, and double immunofluorescence staining. Next, we investigated the role of PHP14 in liver fibrosis and, more specifically, the migration of HSCs by Transwell assay and 3D collagen matrices assay. Finally, we explored the possible molecular mechanisms of the effects of PHP14 on these processes. Our results show that the PHP14 expression is up-regulated in fibrotic liver and mainly in HSCs. Importantly, TGF-β1 can induce PHP14 expression in HSCs accompanied with the activation of HSCs. Consistent with the previous study, PHP14 promotes HSCs migration, especially, promotes 3D floating collagen matrices contraction but inhibits stressed-released matrices contraction. Mechanistically, the PI3Kγ/AKT/Rac1 pathway is involved in migration regulated by PHP14. Moreover, PHP14 specifically mediates the TGF-β1 signaling to PI3Kγ/AKT pathway and regulates HSC migration, and thus participates in liver fibrosis. Our study identified the role of PHP14 in liver fibrosis, particularly HSC migration, and suggested a novel mediator of transducting TGF-β1 signaling to PI3Kγ/AKT/Rac1 pathway. PHP14 is up-regulated in fibrotic liver and activated hepatic stellate cells. The expression of PHP14 is induced by TGF-β1. The migration of hepatic stellate cells is regulated by PHP14. PHP14 is a mediator of TGF-β1 signaling to PI3Kγ/AKT/Rac1 pathway in hepatic stellate cells.

In Vitro and In Vivo Hepatic Differentiation of Adult Somatic Stem Cells and Extraembryonic Stem Cells for Treating End Stage Liver Diseases

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Chenxia Hu

2015-01-01

Full Text Available The shortage of liver donors is a major handicap that prevents most patients from receiving liver transplantation and places them on a waiting list for donated liver tissue. Then, primary hepatocyte transplantation and bioartificial livers have emerged as two alternative treatments for these often fatal diseases. However, another problem has emerged. Functional hepatocytes for liver regeneration are in short supply, and they will dedifferentiate immediately in vitro after they are isolated from liver tissue. Alternative stem-cell-based therapeutic strategies, including hepatic stem cells (HSCs, embryonic stem cells (ESCs, induced pluripotent stem cells (iPSCs, and mesenchymal stem cells (MSCs, are more promising, and more attention has been devoted to these approaches because of the high potency and proliferation ability of the cells. This review will focus on the general characteristics and the progress in hepatic differentiation of adult somatic stem cells and extraembryonic stem cells in vitro and in vivo for the treatment of end stage liver diseases. The hepatic differentiation of stem cells would offer an ideal and promising source for cell therapy and tissue engineering for treating liver diseases.

Mechanisms of bile acid mediated inflammation in the liver.

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Li, Man; Cai, Shi-Ying; Boyer, James L

2017-08-01

Bile acids are synthesized in the liver and are the major component in bile. Impaired bile flow leads to cholestasis that is characterized by elevated levels of bile acid in the liver and serum, followed by hepatocyte and biliary injury. Although the causes of cholestasis have been extensively studied, the molecular mechanisms as to how bile acids initiate liver injury remain controversial. In this chapter, we summarize recent advances in the pathogenesis of bile acid induced liver injury. These include bile acid signaling pathways in hepatocytes as well as the response of cholangiocytes and innate immune cells in the liver in both patients with cholestasis and cholestatic animal models. We focus on how bile acids trigger the production of molecular mediators of neutrophil recruitment and the role of the inflammatory response in this pathological process. These advances point to a number of novel targets where drugs might be judged to be effective therapies for cholestatic liver injury. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioartificial liver and liver transplantation: new modalities for the treatment of liver failure

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DING Yitao

2017-09-01

Full Text Available The main features of liver failure are extensive necrosis of hepatocytes, rapid disease progression, and poor prognosis, and at present, there are no effective drugs and methods for the treatment of liver failure. This article summarizes four treatment methods for liver failure, i.e., medical treatment, cell transplantation, liver transplantation, and artificial liver support therapy, and elaborates on the existing treatment methods. The current medical treatment regimen should be optimized; cell transplantation has not been used in clinical practice; liver transplantation is the most effective method, but it is limited by donor liver shortage and high costs; artificial liver can effectively remove toxic substances in human body. Therefore, this article puts forward artificial liver as a transition for liver transplantation; artificial liver can buy time for liver regeneration or liver transplantation and prolong patients′ survival time and thus has a promising future. The new treatment modality of bioartificial liver combined with liver transplantation may bring good news to patients with liver failure.

Changes at transcriptional level during liver regeneration in the rat

International Nuclear Information System (INIS)

Subba Rao, M.N.; Netrawali, M.S.; Pradhan, D.S.; Sreenivasan, A.

1976-01-01

A great upheaval in RNA synthetic pattern is known to occur during the early periods after partial hepatectomy. Such changes are being studied in regenerating rat liver with a view to understanding regulatory mechanisms of eukaryotic transcription. Follwoing partial hepatectomy, RNA synthesis is rat liver showed graded increase during 4 to 18 hours. At these time intervals, a significant enhancement could be discerned both in template efficiency of chromatin and in RNA polymerase activity in this tissue. Further examination revealed that the activity of RNA polymerase II (extra-nucleolar enzyme) stimulated to a much greater extent as compared to that of RNA polymerase I (nucleolar enzyme). Partial hepatectomy also resulted in significant alterations in turnovers of chromosomal acidic proteins in liver. 32 P-orthophosphate injected intraperitoneally was used in these studies. (author)

Hair cell regeneration in the avian auditory epithelium.

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Stone, Jennifer S; Cotanche, Douglas A

2007-01-01

Regeneration of sensory hair cells in the mature avian inner ear was first described just over 20 years ago. Since then, it has been shown that many other non-mammalian species either continually produce new hair cells or regenerate them in response to trauma. However, mammals exhibit limited hair cell regeneration, particularly in the auditory epithelium. In birds and other non-mammals, regenerated hair cells arise from adjacent non-sensory (supporting) cells. Hair cell regeneration was initially described as a proliferative response whereby supporting cells re-enter the mitotic cycle, forming daughter cells that differentiate into either hair cells or supporting cells and thereby restore cytoarchitecture and function in the sensory epithelium. However, further analyses of the avian auditory epithelium (and amphibian vestibular epithelium) revealed a second regenerative mechanism, direct transdifferentiation, during which supporting cells change their gene expression and convert into hair cells without dividing. In the chicken auditory epithelium, these two distinct mechanisms show unique spatial and temporal patterns, suggesting they are differentially regulated. Current efforts are aimed at identifying signals that maintain supporting cells in a quiescent state or direct them to undergo direct transdifferentiation or cell division. Here, we review current knowledge about supporting cell properties and discuss candidate signaling molecules for regulating supporting cell behavior, in quiescence and after damage. While significant advances have been made in understanding regeneration in non-mammals over the last 20 years, we have yet to determine why the mammalian auditory epithelium lacks the ability to regenerate hair cells spontaneously and whether it is even capable of significant regeneration under additional circumstances. The continued study of mechanisms controlling regeneration in the avian auditory epithelium may lead to strategies for inducing

Systemic agonistic anti-CD40 treatment of tumor bearing mice modulates hepatic myeloid suppressive cells and causes immune-mediated liver damage

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Medina-Echeverz, José; Ma, Chi; Duffy, Austin; Eggert, Tobias; Hawk, Nga; Kleiner, David E.; Korangy, Firouzeh; Greten, Tim F.

2015-01-01

Immune stimulatory monoclonal antibodies are currently evaluated as anti tumor agents. Although overall toxicity appears to be moderate, liver toxicities have been reported and are not completely understood. We studied the effect of systemic CD40 antibody treatment on myeloid cells in spleen and liver. Naïve and tumor-bearing mice were treated systemically with agonistic anti-CD40 antibody. Immune cell subsets in liver and spleen, serum transaminases and liver histologies were analyzed after antibody administration. Nox2−/−, Cd40−/− as well as bone marrow chimeric mice were used to study the mechanism by which agonistic anti-CD40 mediates its effects in vivo. Suppressor function of murine and human tumor-induced myeloid derived suppressive cells was studied upon CD40 ligation. Agonistic CD40 antibody caused liver damage within 24 hours after injection in two unrelated tumor models and mice strains. Using bone marrow chimeras we demonstrated that CD40 antibody-induced hepatitis in tumor-bearing mice was dependent on the presence of CD40-expressing hematopoietic cells. Agonistic CD40 ligation-dependent liver damage was induced by the generation of reactive oxygen species. Furthermore, agonistic CD40 antibody resulted in increased CD80 and CD40 positive liver CD11b+Gr-1+ immature myeloid cells. CD40 ligation on tumor-induced murine and human CD14+HLA-DRlow PBMC from cancer patients reduced their immune suppressor function. Collectively, agonistic CD40 antibody treatment activated tumor-induced, myeloid cells, caused myeloid dependent hepatotoxicity and ameliorated the suppressor function of murine and human MDSC. Collectively, our data suggests that CD40 may mature immunosuppressive myeloid cells and thereby cause liver damage in mice with an accumulation of tumor-induced hepatic MDSC. PMID:25637366

Transiently Active Wnt/β-Catenin Signaling Is Not Required but Must Be Silenced for Stem Cell Function during Muscle Regeneration

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Malea M. Murphy

2014-09-01

Full Text Available Adult muscle’s exceptional capacity for regeneration is mediated by muscle stem cells, termed satellite cells. As with many stem cells, Wnt/β-catenin signaling has been proposed to be critical in satellite cells during regeneration. Using new genetic reagents, we explicitly test in vivo whether Wnt/β-catenin signaling is necessary and sufficient within satellite cells and their derivatives for regeneration. We find that signaling is transiently active in transit-amplifying myoblasts, but is not required for regeneration or satellite cell self-renewal. Instead, downregulation of transiently activated β-catenin is important to limit the regenerative response, as continuous regeneration is deleterious. Wnt/β-catenin activation in adult satellite cells may simply be a vestige of their developmental lineage, in which β-catenin signaling is critical for fetal myogenesis. In the adult, surprisingly, we show that it is not activation but rather silencing of Wnt/β-catenin signaling that is important for muscle regeneration.

Determination of optimized oxygen partial pressure to maximize the liver regenerative potential of the secretome obtained from adipose-derived stem cells.

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Lee, Sang Chul; Kim, Kee-Hwan; Kim, Ok-Hee; Lee, Sang Kuon; Hong, Ha-Eun; Won, Seong Su; Jeon, Sang-Jin; Choi, Byung Jo; Jeong, Wonjun; Kim, Say-June

2017-08-03

A hypoxic-preconditioned secretome from stem cells reportedly promotes the functional and regenerative capacity of the liver more effectively than a control secretome. However, the optimum oxygen partial pressure (pO 2 ) in the cell culture system that maximizes the therapeutic potential of the secretome has not yet been determined. We first determined the cellular alterations in adipose tissue-derived stem cells (ASCs) cultured under different pO 2 (21%, 10%, 5%, and 1%). Subsequently, partially hepatectomized mice were injected with the secretome of ASCs cultured under different pO 2 , and then sera and liver specimens were obtained for analyses. Of all AML12 cells cultured under different pO 2 , the AML12 cells cultured under 1% pO 2 showed the highest mRNA expression of proliferation-associated markers (IL-6, HGF, and VEGF). In the cell proliferation assay, the AML12 cells cultured with the secretome of 1% pO 2 showed the highest cell proliferation, followed by the cells cultured with the secretome of 21%, 10%, and 5% pO 2 , in that order. When injected into the partially hepatectomized mice, the 1% pO 2 secretome most significantly increased the number of Ki67-positive cells, reduced serum levels of proinflammatory mediators (IL-6 and TNF-α), and reduced serum levels of liver transaminases. In addition, analysis of the liver specimens indicated that injection with the 1% pO 2 secretome maximized the expression of the intermediate molecules of the PIP3/Akt and IL-6/STAT3 signaling pathways, all of which are known to promote liver regeneration. The data of this study suggest that the secretome of ASCs cultured under 1% pO 2 has the highest liver reparative and regenerative potential of all the secretomes tested here.

Prostaglandin E2 Regulates Liver versus Pancreas Cell Fate Decisions and Endodermal Outgrowth

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Nissim, Sahar; Sherwood, Richard I.; Wucherpfennig, Julia; Saunders, Diane; Harris, James M.; Esain, Virginie; Carroll, Kelli J.; Frechette, Gregory M.; Kim, Andrew J.; Hwang, Katie L.; Cutting, Claire C.; Elledge, Susanna; North, Trista E.; Goessling, Wolfram

2014-01-01

SUMMARY The liver and pancreas arise from common endodermal progenitors. How these distinct cell fates are specified is poorly understood. Here, we describe prostaglandin E2 (PGE2) as a regulator of endodermal fate specification during development. Modulating PGE2 activity has opposing effects on liver-versus-pancreas specification in zebrafish embryos as well as mouse endodermal progenitors. The PGE2 synthetic enzyme cox2a and receptor ep2a are patterned such that cells closest to PGE2 synthesis acquire a liver fate whereas more distant cells acquire a pancreas fate. PGE2 interacts with the bmp2b pathway to regulate fate specification. At later stages of development, PGE2 acting via the ep4a receptor promotes outgrowth of both the liver and pancreas. PGE2 remains important for adult organ growth, as it modulates liver regeneration. This work provides in vivo evidence that PGE2 may act as a morphogen to regulate cell fate decisions and outgrowth of the embryonic endodermal anlagen. PMID:24530296

Acute Liver Injury Is Independent of B Cells or Immunoglobulin M.

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James A Richards

Full Text Available Acute liver injury is a clinically important pathology and results in the release of Danger Associated Molecular Patterns, which initiate an immune response. Withdrawal of the injurious agent and curtailing any pathogenic secondary immune response may allow spontaneous resolution of injury. The role B cells and Immunoglobulin M (IgM play in acute liver injury is largely unknown and it was proposed that B cells and/or IgM would play a significant role in its pathogenesis.Tissue from 3 models of experimental liver injury (ischemia-reperfusion injury, concanavalin A hepatitis and paracetamol-induced liver injury and patients transplanted following paracetamol overdose were stained for evidence of IgM deposition. Mice deficient in B cells (and IgM were used to dissect out the role B cells and/or IgM played in the development or resolution of injury. Serum transfer into mice lacking IgM was used to establish the role IgM plays in injury.Significant deposition of IgM was seen in the explanted livers of patients transplanted following paracetamol overdose as well as in 3 experimental models of acute liver injury (ischemia-reperfusion injury, concanavalin A hepatitis and paracetamol-induced liver injury. Serum transfer into IgM-deficient mice failed to reconstitute injury (p = 0.66, despite successful engraftment of IgM. Mice deficient in both T and B cells (RAG1-/- mice (p<0.001, but not B cell deficient (μMT mice (p = 0.93, were significantly protected from injury. Further interrogation with T cell deficient (CD3εKO mice confirmed that the T cell component is a key mediator of sterile liver injury. Mice deficient in B cells and IgM mice did not have a significant delay in resolution following acute liver injury.IgM deposition appears to be common feature of both human and murine sterile liver injury. However, neither IgM nor B cells, play a significant role in the development of or resolution from acute liver injury. T cells appear to be key

Elevated phosphatase of regenerating liver 3 (PRL-3) promotes cytoskeleton reorganization, cell migration and invasion in endometrial stromal cells from endometrioma.

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Zhan, Hong; Ma, Junyan; Ruan, Fei; Bedaiwy, Mohamed A; Peng, Bo; Wu, Ruijin; Lin, Jun

2016-04-01

Is phosphatase of regenerating liver-3 (PRL-3) associated with increased motility of endometriotic cells from endometrioma? Elevated PRL-3 promotes cytoskeleton reorganization, cell migration and invasion of endometrial stromal cells (ESCs) from endometrioma. Overexpression of PRL-3 is associated with cancer cell migration, invasion and metastatic phenotype. Primary human ESCs were isolated from eutopic endometrium of women without endometriosis (EuCo, n = 10), with histologically proven endometrioma (EuEM, n = 19) and from the cyst wall of ovarian endometriosis (OvEM, n = 26). The expression of PRL-3 in ESCs derived from EuCo, EuEM and OvEM at different phases of menstrual cycle were compared. The protein and mRNA levels of PRL-3 were examined by western blot and RT-qPCR, respectively. ESCs from OvEM were transfected with/without short hairpin RNA (shRNA) or small interfering RNA (siRNA). Additionally, a plasmid-mediated delivery system was used to achieve PRL-3 overexpression in ESCs from EuEM. The cellular distribution of F-actin and α-tubulin were examined by immunocytochemistry. Cell motility was evaluated by a transwell migration/invasion assay. The protein and mRNA levels of PRL-3 are significantly elevated in ESCs from OvEM compared with EuCo and EuEM. The expression of PRL-3 was not altered between proliferative phase and secretory phase in ESCs from all groups. Knockdown of PRL-3 significantly modified the distribution of F-actin and α-tubulin cytoskeleton, inhibited cell migration and invasion. Endogenous inhibition of PRL-3 attenuated the expression of Ras homolog gene family members A and C (RhoA, RhoC), Rho-associated coiled-coil-containing protein kinase 1 (ROCK1) and matrix metalloproteinase (MMP) 9, but not MMP2 in ESCs from OvEM. Additionally, overexpression of PRL-3 in ESCs from EuEM up-regulates cell migration and invasion, and increases the expression of RhoA, RhoC, ROCK1 and MMP9. Lack of in vivo animal studies is the major limitation of our

Aging-associated oxidative stress inhibits liver progenitor cell activation in mice.

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Cheng, Yiji; Wang, Xue; Wang, Bei; Zhou, Hong; Dang, Shipeng; Shi, Yufang; Hao, Li; Luo, Qingquan; Jin, Min; Zhou, Qianjun; Zhang, Yanyun

2017-04-29

Recent studies have discovered aging-associated changes of adult stem cells in various tissues and organs, which potentially contribute to the organismal aging. However, aging-associated changes of liver progenitor cells (LPCs) remain elusive. Employing young (2-month-old) and old (24-month-old) mice, we found diverse novel alterations in LPC activation during aging. LPCs in young mice could be activated and proliferate upon liver injury, whereas the counterparts in old mice failed to respond and proliferate, leading to the impaired liver regeneration. Surprisingly, isolated LPCs from young and old mice did not exhibit significant difference in their clonogenic and proliferative capacity. Later, we uncovered that the decreased activation and proliferation of LPCs were due to excessive reactive oxygen species produced by neutrophils infiltrated into niche, which was resulted from chemokine production from activated hepatic stellate cells during aging. This study demonstrates aging-associated changes in LPC activation and reveals critical roles for the stem cell niche, including neutrophils and hepatic stellate cells, in the negative regulation of LPCs during aging.

Centroacinar cells: At the center of pancreas regeneration.

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Beer, Rebecca L; Parsons, Michael J; Rovira, Meritxell

2016-05-01

The process of regeneration serves to heal injury by replacing missing cells. Understanding regeneration can help us replace cell populations lost during disease, such as the insulin-producing β cells lost in diabetic patients. Centroacinar cells (CACs) are a specialized ductal pancreatic cell type that act as progenitors to replace β cells in the zebrafish. However, whether CACs contribute to β-cell regeneration in adult mammals remains controversial. Here we review the current understanding of the role of CACs as endocrine progenitors during regeneration in zebrafish and mammals. Copyright © 2016 Elsevier Inc. All rights reserved.

Regenerating the injured kidney with human umbilical cord mesenchymal stem cell-derived exosomes

OpenAIRE

Dorronsoro, Akaitz; Robbins, Paul D

2013-01-01

Transplantation of adult stem cells is being used to facilitate repair or regeneration of damaged or diseased tissues. However, in many cases, the therapeutic effects of the injected stem cells are mediated by factors secreted by stem cells and not by differentiation of the transplanted stem cells. Recent reports have identified a class of microvesicles, termed exosomes, released by stem cells that are able to confer therapeutic effects on injured renal and cardiac tissue. In this issue of St...

Engraftment and reconstitution of hematopoiesis is dependent on VEGFR2 mediated regeneration of sinusoidal endothelial cells

Science.gov (United States)

Hooper, Andrea T.; Butler, Jason M.; Nolan, Daniel J; Kranz, Andrea; Iida, Kaoruko; Kobayashi, Mariko; Kopp, Hans-Georg; Shido, Koji; Petit, Isabelle; Yanger, Kilangsungla; James, Daylon; Witte, Larry; Zhu, Zhenping; Wu, Yan; Pytowski, Bronislaw; Rosenwaks, Zev; Mittal, Vivek; Sato, Thomas N.; Rafii, Shahin

2011-01-01

SUMMARY The phenotypic attributes and molecular determinants for the regeneration of bone marrow (BM) sinusoidal endothelial cells (SECs) and their contribution to hematopoiesis are unknown. We show that after myelosuppression VEGFR2 activation promotes reassembly of regressed SECs, reconstituting hematopoietic stem and progenitor cells (HSPCs). VEGFR2 and VEGFR3 expression are restricted to BM vasculature, demarcating a continuous network of VEGFR2+VEGFR3+Sca1− SECs and VEGFR2+VEGFR3−Sca1+ arterioles. While chemotherapy (5FU) and sublethal irradiation (650 rad) induce minor SEC regression, lethal irradiation (950 rad) induces severe regression of SECs requiring BM transplantation (BMT) for regeneration. Conditional deletion of VEGFR2 in adult mice blocks regeneration of SECs in sublethally irradiated animals, preventing hematopoietic reconstitution. Inhibition of VEGFR2 signaling in lethally irradiated wild type mice rescued with BMT severely impairs SEC reconstruction, preventing engraftment and reconstitution of HSPCs. Therefore, activation of VEGFR2 is critical for regeneration of VEGFR3+Sca1− SECs that are essential for engraftment and restoration of HSPCs and hematopoiesis. PMID:19265665

Regeneration of pancreatic non-β endocrine cells in adult mice following a single diabetes-inducing dose of streptozotocin.

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Yanqing Zhang

Full Text Available The non-β endocrine cells in pancreatic islets play an essential counterpart and regulatory role to the insulin-producing β-cells in the regulation of blood-glucose homeostasis. While significant progress has been made towards the understanding of β-cell regeneration in adults, very little is known about the regeneration of the non-β endocrine cells such as glucagon-producing α-cells and somatostatin producing δ-cells. Previous studies have noted the increase of α-cell composition in diabetes patients and in animal models. It is thus our hypothesis that non-β-cells such as α-cells and δ-cells in adults can regenerate, and that the regeneration accelerates in diabetic conditions. To test this hypothesis, we examined islet cell composition in a streptozotocin (STZ-induced diabetes mouse model in detail. Our data showed the number of α-cells in each islet increased following STZ-mediated β-cell destruction, peaked at Day 6, which was about 3 times that of normal islets. In addition, we found δ-cell numbers doubled by Day 6 following STZ treatment. These data suggest α- and δ-cell regeneration occurred rapidly following a single diabetes-inducing dose of STZ in mice. Using in vivo BrdU labeling techniques, we demonstrated α- and δ-cell regeneration involved cell proliferation. Co-staining of the islets with the proliferating cell marker Ki67 showed α- and δ-cells could replicate, suggesting self-duplication played a role in their regeneration. Furthermore, Pdx1(+/Insulin(- cells were detected following STZ treatment, indicating the involvement of endocrine progenitor cells in the regeneration of these non-β cells. This is further confirmed by the detection of Pdx1(+/glucagon(+ cells and Pdx1(+/somatostatin(+ cells following STZ treatment. Taken together, our study demonstrated adult α- and δ-cells could regenerate, and both self-duplication and regeneration from endocrine precursor cells were involved in their regeneration.

Regeneration of hair cells in the mammalian vestibular system.

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Li, Wenyan; You, Dan; Chen, Yan; Chai, Renjie; Li, Huawei

2016-06-01

Hair cells regenerate throughout the lifetime of non-mammalian vertebrates, allowing these animals to recover from hearing and balance deficits. Such regeneration does not occur efficiently in humans and other mammals. Thus, balance deficits become permanent and is a common sensory disorder all over the world. Since Forge and Warchol discovered the limited spontaneous regeneration of vestibular hair cells after gentamicininduced damage in mature mammals, significant efforts have been exerted to trace the origin of the limited vestibular regeneration in mammals after hair cell loss. Moreover, recently many strategies have been developed to promote the hair cell regeneration and subsequent functional recovery of the vestibular system, including manipulating the Wnt, Notch and Atoh1. This article provides an overview of the recent advances in hair cell regeneration in mammalian vestibular epithelia. Furthermore, this review highlights the current limitations of hair cell regeneration and provides the possible solutions to regenerate functional hair cells and to partially restore vestibular function.

Tumor induced hepatic myeloid derived suppressor cells can cause moderate liver damage.

Science.gov (United States)

Eggert, Tobias; Medina-Echeverz, José; Kapanadze, Tamar; Kruhlak, Michael J; Korangy, Firouzeh; Greten, Tim F

2014-01-01

Subcutaneous tumors induce the accumulation of myeloid derived suppressor cells (MDSC) not only in blood and spleens, but also in livers of these animals. Unexpectedly, we observed a moderate increase in serum transaminases in mice with EL4 subcutaneous tumors, which prompted us to study the relationship of hepatic MDSC accumulation and liver injury. MDSC were the predominant immune cell population expanding in livers of all subcutaneous tumor models investigated (RIL175, B16, EL4, CT26 and BNL), while liver injury was only observed in EL4 and B16 tumor-bearing mice. Elimination of hepatic MDSC in EL4 tumor-bearing mice using low dose 5-fluorouracil (5-FU) treatment reversed transaminase elevation and adoptive transfer of hepatic MDSC from B16 tumor-bearing mice caused transaminase elevation indicating a direct MDSC mediated effect. Surprisingly, hepatic MDSC from B16 tumor-bearing mice partially lost their damage-inducing potency when transferred into mice bearing non damage-inducing RIL175 tumors. Furthermore, MDSC expansion and MDSC-mediated liver injury further increased with growing tumor burden and was associated with different cytokines including GM-CSF, VEGF, interleukin-6, CCL2 and KC, depending on the tumor model used. In contrast to previous findings, which have implicated MDSC only in protection from T cell-mediated hepatitis, we show that tumor-induced hepatic MDSC themselves can cause moderate liver damage.

Elevated mitochondrial gene expression during rat liver regeneration after portal vein ligation.

Science.gov (United States)

Shimizu, Y; Suzuki, H; Nimura, Y; Onoue, S; Nagino, M; Tanaka, M; Ozawa, T

1995-10-01

We explored the molecular basis of mitochondrial energy production during rat liver regeneration after portal vein ligation. Ligation of the left branch of the portal vein induces an increase in the weight of the nonligated lobe, counterbalancing the reduced weight of the ligated lobe. Using this model, we investigated changes in mitochondrial DNA-binding proteins, mitochondrial DNA, and mitochondrial messenger RNA (mRNA) in rat hepatocytes of the nonligated lobes. The amount of mitochondrial DNA-binding protein increased maximally (200% to 300% of the preoperative level) at 12 hours after the operation, before an increase (390%) in mitochondrial DNA content at 24 hours, and parallel to an increase (240%) in mitochondrial mRNA levels at 12 hours. These results suggest that the energy supply for liver regeneration is achieved through enhancement of mitochondrial DNA replication as well as transcription, in which the mitochondrial DNA-binding proteins probably play regulatory roles. We also found that in the nonligated lobes, mRNA levels of hepatocyte growth factor increased to a detectable level only 12 hours after the operation. These molecular biochemical data help explain why preoperative portal vein embolization, which is a modification of portal vein branch ligation, is an effective method to prevent posthepatectomy liver failure.

Expression analysis on 14-3-3 proteins in regenerative liver following partial hepatectomy

OpenAIRE

Xue, Deming; Xue, Yang; Niu, Zhipeng; Guo, Xueqiang; Xu, Cunshuan

2017-01-01

Abstract 14-3-3 proteins play a vital part in the regulation of cell cycle and apoptosis as signaling integration points. During liver regeneration, the quiescent hepatocytes go through hypertrophy and proliferation to restore liver weight. Therefore, we speculated that 14-3-3 proteins regulate the progression of liver regeneration. In this study, we analyzed the expression patterns of 14-3-3 proteins during liver regeneration of rat to provide an insight into the regenerative mechanism using...

Müller stem cell dependent retinal regeneration.

Science.gov (United States)

Chohan, Annu; Singh, Usha; Kumar, Atul; Kaur, Jasbir

2017-01-01

Müller Stem cells to treat ocular diseases has triggered enthusiasm across all medical and scientific communities. Recent development in the field of stem cells has widened the prospects of applying cell based therapies to regenerate ocular tissues that have been irreversibly damaged by disease or injury. Ocular tissues such as the lens and the retina are now known to possess cell having remarkable regenerative abilities. Recent studies have shown that the Müller glia, a cell found in all vertebrate retinas, is the primary source of new neurons, and therefore are considered as the cellular basis for retinal regeneration in mammalian retinas. Here, we review the current status of retinal regeneration of the human eye by Müller stem cells. This review elucidates the current status of retinal regeneration by Müller stem cells, along with major retinal degenerative diseases where these stem cells play regenerative role in retinal repair and replacement. Copyright © 2016. Published by Elsevier B.V.

2,3,7,8-TCDD enhances the sensitivity of mice to concanavalin A immune-mediated liver injury

Energy Technology Data Exchange (ETDEWEB)

Fullerton, Aaron M., E-mail: fuller22@msu.edu [Department of Pharmacology and Toxicology, Center for Integrative Toxicology, Michigan State University, 1129 Farm Lane, Room 215, East Lansing, MI 48824 (United States); Roth, Robert A., E-mail: rothr@msu.edu [Department of Pharmacology and Toxicology, Center for Integrative Toxicology, Michigan State University, Food Safety and Toxicology Building, 1129 Farm Lane, Room 221, East Lansing, MI 48824 (United States); Ganey, Patricia E., E-mail: ganey@msu.edu [Department of Pharmacology and Toxicology, Center for Integrative Toxicology, Michigan State University, Food Safety and Toxicology Building, 1129 Farm Lane, Room 214, East Lansing, MI 48824 (United States)

2013-01-15

Inflammation plays a major role in immune-mediated liver injury, and exposure to environmental pollutants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been reported to alter the inflammatory response as well as affect immune cell activity. In this study, we tested the hypothesis that TCDD pretreatment exacerbates hepatotoxicity in a murine model of immune-mediated liver injury induced by concanavalin A (Con A) administration. Mice were pretreated with 30 μg/kg TCDD or vehicle control on day zero and then given either Con A or saline intravenously on day four. Mice treated with TCDD did not develop liver injury; however, TCDD pretreatment increased liver injury resulting from moderate doses of Con A (4–10 mg/kg). TCDD-pretreated mice had altered plasma concentrations of inflammatory cytokines, including interferon gamma (IFNγ), and TCDD/Con A-induced hepatotoxicity was attenuated in IFNγ knockout mice. At various times after treatment, intrahepatic immune cells were isolated, and expression of cell activation markers as well as cytolytic proteins was determined. TCDD pretreatment increased the proportion of activated natural killer T (NKT) cells and the percent of cells expressing Fas ligand (FasL) after Con A administration. In addition FasL knockout mice and mice treated with CD18 antiserum were both protected from TCDD/Con A-induced hepatotoxicity, suggesting a requirement for direct cell–cell interaction between effector immune cells and parenchymal cell targets in the development of liver injury from TCDD/Con A treatment. In summary, exposure to TCDD increased NKT cell activation and exacerbated immune-mediated liver injury induced by Con A through a mechanism involving IFNγ and FasL expression. -- Highlights: ► TCDD pretreatment sensitizes mice to Con A-induced hepatotoxicity. ► TCDD pretreatment increased concentration of IFNγ in plasma after Con A. ► Con A-induced activation of NKT cells was increased by TCDD pretreatment. ► Fas

2,3,7,8-TCDD enhances the sensitivity of mice to concanavalin A immune-mediated liver injury

International Nuclear Information System (INIS)

Fullerton, Aaron M.; Roth, Robert A.; Ganey, Patricia E.

2013-01-01

Inflammation plays a major role in immune-mediated liver injury, and exposure to environmental pollutants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been reported to alter the inflammatory response as well as affect immune cell activity. In this study, we tested the hypothesis that TCDD pretreatment exacerbates hepatotoxicity in a murine model of immune-mediated liver injury induced by concanavalin A (Con A) administration. Mice were pretreated with 30 μg/kg TCDD or vehicle control on day zero and then given either Con A or saline intravenously on day four. Mice treated with TCDD did not develop liver injury; however, TCDD pretreatment increased liver injury resulting from moderate doses of Con A (4–10 mg/kg). TCDD-pretreated mice had altered plasma concentrations of inflammatory cytokines, including interferon gamma (IFNγ), and TCDD/Con A-induced hepatotoxicity was attenuated in IFNγ knockout mice. At various times after treatment, intrahepatic immune cells were isolated, and expression of cell activation markers as well as cytolytic proteins was determined. TCDD pretreatment increased the proportion of activated natural killer T (NKT) cells and the percent of cells expressing Fas ligand (FasL) after Con A administration. In addition FasL knockout mice and mice treated with CD18 antiserum were both protected from TCDD/Con A-induced hepatotoxicity, suggesting a requirement for direct cell–cell interaction between effector immune cells and parenchymal cell targets in the development of liver injury from TCDD/Con A treatment. In summary, exposure to TCDD increased NKT cell activation and exacerbated immune-mediated liver injury induced by Con A through a mechanism involving IFNγ and FasL expression. -- Highlights: ► TCDD pretreatment sensitizes mice to Con A-induced hepatotoxicity. ► TCDD pretreatment increased concentration of IFNγ in plasma after Con A. ► Con A-induced activation of NKT cells was increased by TCDD pretreatment. ► Fas

Attenuated lipotoxicity and apoptosis is linked to exogenous and endogenous augmenter of liver regeneration by different pathways.

Science.gov (United States)

Weiss, Thomas S; Lupke, Madeleine; Ibrahim, Sara; Buechler, Christa; Lorenz, Julia; Ruemmele, Petra; Hofmann, Ute; Melter, Michael; Dayoub, Rania

2017-01-01

Nonalcoholic fatty liver disease (NAFLD) covers a spectrum from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. Free fatty acids (FFA) induce steatosis and lipo-toxicity and correlate with severity of NAFLD. In this study we aimed to investigate the role of exogenous and endogenous ALR (augmenter of liver regeneration) for FFA induced ER (endoplasmatic reticulum) -stress and lipoapoptosis. Primary human hepatocytes or hepatoma cells either treated with recombinant human ALR (rhALR, 15kDa) or expressing short form ALR (sfALR, 15kDa) were incubated with palmitic acid (PA) and analyzed for lipo-toxicity, -apoptosis, activation of ER-stress response pathways, triacylglycerides (TAG), mRNA and protein expression of lipid metabolizing genes. Both, exogenous rhALR and cytosolic sfALR reduced PA induced caspase 3 activity and Bax protein expression and therefore lipotoxicity. Endogenous sfALR but not rhALR treatment lowered TAG levels, diminished activation of ER-stress mediators C-Jun N-terminal kinase (JNK), X-box binding protein-1 (XBP1) and proapoptotic transcription factor C/EBP-homologous protein (CHOP), and reduced death receptor 5 protein expression. Cellular ALR exerts its lipid lowering and anti-apoptotic actions by enhancing FABP1, which binds toxic FFA, increasing mitochondrial β-oxidation by elevating the mitochondrial FFA transporter CPT1α, and decreasing ELOVL6, which delivers toxic FFA metabolites. We found reduced hepatic mRNA levels of ALR in a high fat diet mouse model, and of ALR and FOXA2, a transcription factor inducing ALR expression, in human steatotic as well as NASH liver samples, which may explain increased lipid deposition and reduced β-oxidation in NASH patients. Present study shows that exogenous and endogenous ALR reduce PA induced lipoapoptosis. Furthermore, cytosolic sfALR changes mRNA and protein expression of genes regulating lipid metabolism, reduces ER-stress finally impeding progression of NASH.

Attenuated lipotoxicity and apoptosis is linked to exogenous and endogenous augmenter of liver regeneration by different pathways.

Directory of Open Access Journals (Sweden)

Thomas S Weiss

Full Text Available Nonalcoholic fatty liver disease (NAFLD covers a spectrum from simple steatosis to nonalcoholic steatohepatitis (NASH and cirrhosis. Free fatty acids (FFA induce steatosis and lipo-toxicity and correlate with severity of NAFLD. In this study we aimed to investigate the role of exogenous and endogenous ALR (augmenter of liver regeneration for FFA induced ER (endoplasmatic reticulum -stress and lipoapoptosis. Primary human hepatocytes or hepatoma cells either treated with recombinant human ALR (rhALR, 15kDa or expressing short form ALR (sfALR, 15kDa were incubated with palmitic acid (PA and analyzed for lipo-toxicity, -apoptosis, activation of ER-stress response pathways, triacylglycerides (TAG, mRNA and protein expression of lipid metabolizing genes. Both, exogenous rhALR and cytosolic sfALR reduced PA induced caspase 3 activity and Bax protein expression and therefore lipotoxicity. Endogenous sfALR but not rhALR treatment lowered TAG levels, diminished activation of ER-stress mediators C-Jun N-terminal kinase (JNK, X-box binding protein-1 (XBP1 and proapoptotic transcription factor C/EBP-homologous protein (CHOP, and reduced death receptor 5 protein expression. Cellular ALR exerts its lipid lowering and anti-apoptotic actions by enhancing FABP1, which binds toxic FFA, increasing mitochondrial β-oxidation by elevating the mitochondrial FFA transporter CPT1α, and decreasing ELOVL6, which delivers toxic FFA metabolites. We found reduced hepatic mRNA levels of ALR in a high fat diet mouse model, and of ALR and FOXA2, a transcription factor inducing ALR expression, in human steatotic as well as NASH liver samples, which may explain increased lipid deposition and reduced β-oxidation in NASH patients. Present study shows that exogenous and endogenous ALR reduce PA induced lipoapoptosis. Furthermore, cytosolic sfALR changes mRNA and protein expression of genes regulating lipid metabolism, reduces ER-stress finally impeding progression of NASH.

Cell-mediated mutagenesis and cell transformation of mammalian cells by chemical carcinogens

International Nuclear Information System (INIS)

Huberman, E.; Langenbach, R.

1977-01-01

We have developed a cell-mediated mutagenesis assay in which cells with the appropriate markers for mutagenesis are co-cultivated with either lethally irradiated rodent embryonic cells that can metabolize carcinogenic hydrocarbons or with primary rat liver cells that can metabolize chemicals carcinogenic to the liver. During co-cultivation, the reactive metabolites of the procarcinogen appear to be transmitted to the mutable cells and induce mutations in them. Assays of this type make it possible to demonstrate a relationship between carcinogenic potency of the chemicals and their ability to induce mutations in mammalian cells. In addition, by simultaneously comparing the frequencies of transformation and mutation induced in normal diploid hamster cells by benzo(a)pyrene (BP) and one of its metabolites, it is possible to estimate the genetic target size for cell transformation in vitro

Restoration of CpG Methylation in The Egf Promoter Region during Rat Liver Regeneration

Science.gov (United States)

Deming, Li; Ziwei, Li; Xueqiang, Guo; Cunshuan, Xu

2015-01-01

Epidermal growth factor (EGF) is an important factor for healing after tissue damage in diverse experimental models. It plays an important role in liver regeneration (LR). The objective of this experiment is to investigate the methylation variation of 10 CpG sites in the Egf promoter region and their relevance to Egf expression during rat liver regenera- tion. As a follow up of our previous study, rat liver tissue was collected after rat 2/3 partial hepatectomy (PH) during the re-organization phase (from days 14 to days 28). Liver DNA was extracted and modified by sodium bisulfate. The methylation status of 10 CpG sites in Egf promoter region was determined using bisulfite sequencing polymerase chain reaction (PCR), as BSP method. The results showed that 3 (sites 3, 4 and 9) out of 10 CpG sites have strikingly methylation changes during the re-organization phase compared to the regeneration phase (from 2 hours to 168 hours, P=0.002, 0.048 and 0.018, respectively). Our results showed that methylation modification of CpGs in the Egf promoter region could be restored to the status before PH operation and changes of methylation didn’t affect Egf mRNA expression during the re-organization phase. PMID:26464832

ICAM-1 triggers liver regeneration through leukocyte recruitment and Kupffer cell-dependent release of TNF-alpha/IL-6 in mice.

NARCIS (Netherlands)

Selzner, N; Selzner, M; Odermatt, B; Tian, Y; Rooijen, van N.; Clavien, PA

2003-01-01

AIMS: Tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 mediate hepatocyte proliferation in vivo, suggesting that local and systemic inflammatory reactions may trigger hepatic regeneration after major tissue loss. METHODS: Wild-type, intercellular adhesion molecule (ICAM)-1-/-, and

Composite cell sheet for periodontal regeneration: crosstalk between different types of MSCs in cell sheet facilitates complex periodontal-like tissue regeneration.

Science.gov (United States)

Zhang, Hao; Liu, Shiyu; Zhu, Bin; Xu, Qiu; Ding, Yin; Jin, Yan

2016-11-14

Tissue-engineering strategies based on mesenchymal stem cells (MSCs) and cell sheets have been widely used for periodontal tissue regeneration. However, given the complexity in periodontal structure, the regeneration methods using a single species of MSC could not fulfill the requirement for periodontal regeneration. We researched the interaction between the periodontal ligament stem cells (PDLSCs) and jaw bone marrow-derived mesenchymal stem cells (JBMMSCs), and constructed a composite cell sheet comprising both of the above MSCs to regenerate complex periodontium-like structures in nude mice. Our results show that by co-culturing PDLSCs and JBMMSCs, the expressions of bone and extracellular matrix (ECM)-related genes and proteins were significantly improved in both MSCs. Further investigations showed that, compared to the cell sheet using PDLSCs or JBMMSCs, the composite stem cell sheet (CSCS), which comprises these two MSCs, expressed higher levels of bone- and ECM-related genes and proteins, and generated a composite structure more similar to the native periodontal tissue physiologically in vivo. In conclusion, our results demonstrate that the crosstalk between PDLSCs and JBMMSCs in cell sheets facilitate regeneration of complex periodontium-like structures, providing a promising new strategy for physiological and functional regeneration of periodontal tissue.

Sensory hair cell death and regeneration in fishes

Directory of Open Access Journals (Sweden)

Jerry D. Monroe

2015-04-01

Full Text Available Sensory hair cells are specialized mechanotransductive receptors required for hearing and vestibular function. Loss of hair cells in humans and other mammals is permanent and causes reduced hearing and balance. In the early 1980’s, it was shown that hair cells continue to be added to the inner ear sensory epithelia in cartilaginous and bony fishes. Soon thereafter, hair cell regeneration was documented in the chick cochlea following acoustic trauma. Since then, research using chick and other avian models has led to great insights into hair cell death and regeneration. However, with the rise of the zebrafish as a model organism for studying disease and developmental processes, there has been an increased interest in studying sensory hair cell death and regeneration in its lateral line and inner ears. Advances derived from studies in zebrafish and other fish species include understanding the effect of ototoxins on hair cells and finding otoprotectants to mitigate ototoxin damage, the role of cellular proliferation versus direct transdifferentiation during hair cell regeneration, and elucidating cellular pathways involved in the regeneration process. This review will summarize research on hair cell death and regeneration using fish models, indicate the potential strengths and weaknesses of these models, and discuss several emerging areas of future studies.

Tumor induced hepatic myeloid derived suppressor cells can cause moderate liver damage.

Directory of Open Access Journals (Sweden)

Tobias Eggert

Full Text Available Subcutaneous tumors induce the accumulation of myeloid derived suppressor cells (MDSC not only in blood and spleens, but also in livers of these animals. Unexpectedly, we observed a moderate increase in serum transaminases in mice with EL4 subcutaneous tumors, which prompted us to study the relationship of hepatic MDSC accumulation and liver injury. MDSC were the predominant immune cell population expanding in livers of all subcutaneous tumor models investigated (RIL175, B16, EL4, CT26 and BNL, while liver injury was only observed in EL4 and B16 tumor-bearing mice. Elimination of hepatic MDSC in EL4 tumor-bearing mice using low dose 5-fluorouracil (5-FU treatment reversed transaminase elevation and adoptive transfer of hepatic MDSC from B16 tumor-bearing mice caused transaminase elevation indicating a direct MDSC mediated effect. Surprisingly, hepatic MDSC from B16 tumor-bearing mice partially lost their damage-inducing potency when transferred into mice bearing non damage-inducing RIL175 tumors. Furthermore, MDSC expansion and MDSC-mediated liver injury further increased with growing tumor burden and was associated with different cytokines including GM-CSF, VEGF, interleukin-6, CCL2 and KC, depending on the tumor model used. In contrast to previous findings, which have implicated MDSC only in protection from T cell-mediated hepatitis, we show that tumor-induced hepatic MDSC themselves can cause moderate liver damage.

Macrophages and dendritic cells emerge in the liver during intestinal inflammation and predispose the liver to inflammation.

Directory of Open Access Journals (Sweden)

Yohei Mikami

Full Text Available The liver is a physiological site of immune tolerance, the breakdown of which induces immunity. Liver antigen-presenting cells may be involved in both immune tolerance and activation. Although inflammatory diseases of the liver are frequently associated with inflammatory bowel diseases, the underlying immunological mechanisms remain to be elucidated. Here we report two murine models of inflammatory bowel disease: RAG-2(-/- mice adoptively transferred with CD4(+CD45RB(high T cells; and IL-10(-/- mice, accompanied by the infiltration of mononuclear cells in the liver. Notably, CD11b(-CD11c(lowPDCA-1(+ plasmacytoid dendritic cells (DCs abundantly residing in the liver of normal wild-type mice disappeared in colitic CD4(+CD45RB(high T cell-transferred RAG-2(-/- mice and IL-10(-/- mice in parallel with the emergence of macrophages (Mφs and conventional DCs (cDCs. Furthermore, liver Mφ/cDCs emerging during intestinal inflammation not only promote the proliferation of naïve CD4(+ T cells, but also instruct them to differentiate into IFN-γ-producing Th1 cells in vitro. The emergence of pathological Mφ/cDCs in the liver also occurred in a model of acute dextran sulfate sodium (DSS-induced colitis under specific pathogen-free conditions, but was canceled in germ-free conditions. Last, the Mφ/cDCs that emerged in acute DSS colitis significantly exacerbated Fas-mediated hepatitis. Collectively, intestinal inflammation skews the composition of antigen-presenting cells in the liver through signaling from commensal bacteria and predisposes the liver to inflammation.

Identification of Pathways in Liver Repair Potentially Targeted by Secretory Proteins from Human Mesenchymal Stem Cells

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Sandra Winkler

2016-07-01

Full Text Available Background: The beneficial impact of mesenchymal stem cells (MSC on both acute and chronic liver diseases has been confirmed, although the molecular mechanisms behind it remain elusive. We aim to identify factors secreted by undifferentiated and hepatocytic differentiated MSC in vitro in order to delineate liver repair pathways potentially targeted by MSC. Methods: Secreted factors were determined by protein arrays and related pathways identified by biomathematical analyses. Results: MSC from adipose tissue and bone marrow expressed a similar pattern of surface markers. After hepatocytic differentiation, CD54 (intercellular adhesion molecule 1, ICAM-1 increased and CD166 (activated leukocyte cell adhesion molecule, ALCAM decreased. MSC secreted different factors before and after differentiation. These comprised cytokines involved in innate immunity and growth factors regulating liver regeneration. Pathway analysis revealed cytokine-cytokine receptor interactions, chemokine signalling pathways, the complement and coagulation cascades as well as the Januskinase-signal transducers and activators of transcription (JAK-STAT and nucleotide-binding oligomerization domain-like receptor (NOD-like receptor signalling pathways as relevant networks. Relationships to transforming growth factor β (TGF-β and hypoxia-inducible factor 1-α (HIF1-α signalling seemed also relevant. Conclusion: MSC secreted proteins, which differed depending on cell source and degree of differentiation. The factors might address inflammatory and growth factor pathways as well as chemo-attraction and innate immunity. Since these are prone to dysregulation in most liver diseases, MSC release hepatotropic factors, potentially supporting liver regeneration.

NKT-cell subsets: promoters and protectors in inflammatory liver disease.

Science.gov (United States)

Kumar, Vipin

2013-09-01

Natural killer T cells (NKT) are innate-like cells which are abundant in liver sinusoids and express the cell surface receptors of NK cells (e.g., NK1.1 (mouse) or CD161+/CD56+(human)) as well as an antigen receptor (TCR) characteristic of conventional T cells. NKT cells recognize lipid antigens in the context of CD1d, a non-polymorphic MHC class I-like molecule. Activation of NKT cells has a profound influence on the immune response against tumors and infectious organisms and in autoimmune diseases. NKT cells can be categorized into at least two distinct subsets: iNKT or type I use a semi-invariant TCR, whereas type II NKT TCRs are more diverse. Recent evidence suggests that NKT-cell subsets can play opposing roles early in non-microbial liver inflammation in that type I NKT are proinflammatory whereas type II NKT cells inhibit type I NKT-mediated liver injury. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Impact of cycling cells and cell cycle regulation on Hydra regeneration.

Science.gov (United States)

Buzgariu, Wanda; Wenger, Yvan; Tcaciuc, Nina; Catunda-Lemos, Ana-Paula; Galliot, Brigitte

2018-01-15

Hydra tissues are made from three distinct populations of stem cells that continuously cycle and pause in G2 instead of G1. To characterize the role of cell proliferation after mid-gastric bisection, we have (i) used flow cytometry and classical markers to monitor cell cycle modulations, (ii) quantified the transcriptomic regulations of 202 genes associated with cell proliferation during head and foot regeneration, and (iii) compared the impact of anti-proliferative treatments on regeneration efficiency. We confirm two previously reported events: an early mitotic wave in head-regenerating tips, when few cell cycle genes are up-regulated, and an early-late wave of proliferation on the second day, preceded by the up-regulation of 17 cell cycle genes. These regulations appear more intense after mid-gastric bisection than after decapitation, suggesting a position-dependent regulation of cell proliferation during head regeneration. Hydroxyurea, which blocks S-phase progression, delays head regeneration when applied before but not after bisection. This result is consistent with the fact that the Hydra central region is enriched in G2-paused adult stem cells, poised to divide upon injury, thus forming a necessary constitutive pro-blastema. However a prolonged exposure to hydroxyurea does not block regeneration as cells can differentiate apical structures without traversing S-phase, and also escape in few days the hydroxyurea-induced S-phase blockade. Thus Hydra head regeneration, which is a fast event, is highly plastic, relying on large stocks of adult stem cells paused in G2 at amputation time, which immediately divide to proliferate and/or differentiate apical structures even when S-phase is blocked. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Protein-releasing polymeric scaffolds induce fibrochondrocytic differentiation of endogenous cells for knee meniscus regeneration in sheep

Science.gov (United States)

Lee, Chang H.; Rodeo, Scott A.; Fortier, Lisa Ann; Lu, Chuanyong; Erisken, Cevat

2015-01-01

Regeneration of complex tissues, such as kidney, liver, and cartilage, continues to be a scientific and translational challenge. Survival of ex vivo cultured, transplanted cells in tissue grafts is among one of the key barriers. Meniscus is a complex tissue consisting of collagen fibers and proteoglycans with gradient phenotypes of fibrocartilage and functions to provide congruence of the knee joint, without which the patient is likely to develop arthritis. Endogenous stem/progenitor cells regenerated the knee meniscus upon spatially released human connective tissue growth factor (CTGF) and transforming growth factor–β3 (TGFβ3) from a three-dimensional (3D)–printed biomaterial, enabling functional knee recovery. Sequentially applied CTGF and TGFβ3 were necessary and sufficient to propel mesenchymal stem/progenitor cells, as a heterogeneous population or as single-cell progenies, into fibrochondrocytes that concurrently synthesized procollagens I and IIα. When released from microchannels of 3D–printed, human meniscus scaffolds, CTGF and TGFβ3 induced endogenous stem/progenitor cells to differentiate and synthesize zone-specific type I and II collagens. We then replaced sheep meniscus with anatomically correct, 3D–printed scaffolds that incorporated spatially delivered CTGF and TGFβ3. Endogenous cells regenerated the meniscus with zone-specific matrix phenotypes: primarily type I collagen in the outer zone, and type II collagen in the inner zone, reminiscent of the native meniscus. Spatiotemporally delivered CTGF and TGFβ3 also restored inhomogeneous mechanical properties in the regenerated sheep meniscus. Survival and directed differentiation of endogenous cells in a tissue defect may have implications in the regeneration of complex (heterogeneous) tissues and organs. PMID:25504882

NK Cell Subtypes as Regulators of Autoimmune Liver Disease

Directory of Open Access Journals (Sweden)

Guohui Jiao

2016-01-01

Full Text Available As major components of innate immunity, NK cells not only exert cell-mediated cytotoxicity to destroy tumors or infected cells, but also act to regulate the functions of other cells in the immune system by secreting cytokines and chemokines. Thus, NK cells provide surveillance in the early defense against viruses, intracellular bacteria, and cancer cells. However, the effecter function of NK cells must be exquisitely controlled to prevent inadvertent attack against normal “self” cells. In an organ such as the liver, where the distinction between immunotolerance and immune defense against routinely processed pathogens is critical, the plethora of NK cells has a unique role in the maintenance of homeostasis. Once self-tolerance is broken, autoimmune liver disease resulted. NK cells act as a “two-edged weapon” and even play opposite roles with both regulatory and inducer activities in the hepatic environment. That is, NK cells act not only to produce inflammatory cytokines and chemokines, but also to alter the proliferation and activation of associated lymphocytes. However, the precise regulatory mechanisms at work in autoimmune liver diseases remain to be identified. In this review, we focus on recent research with NK cells and their potential role in the development of autoimmune liver disease.

Precise let-7 expression levels balance organ regeneration against tumor suppression

Science.gov (United States)

Wu, Linwei; Nguyen, Liem H; Zhou, Kejin; de Soysa, T Yvanka; Li, Lin; Miller, Jason B; Tian, Jianmin; Locker, Joseph; Zhang, Shuyuan; Shinoda, Gen; Seligson, Marc T; Zeitels, Lauren R; Acharya, Asha; Wang, Sam C; Mendell, Joshua T; He, Xiaoshun; Nishino, Jinsuke; Morrison, Sean J; Siegwart, Daniel J; Daley, George Q; Shyh-Chang, Ng; Zhu, Hao

2015-01-01

The in vivo roles for even the most intensely studied microRNAs remain poorly defined. Here, analysis of mouse models revealed that let-7, a large and ancient microRNA family, performs tumor suppressive roles at the expense of regeneration. Too little or too much let-7 resulted in compromised protection against cancer or tissue damage, respectively. Modest let-7 overexpression abrogated MYC-driven liver cancer by antagonizing multiple let-7 sensitive oncogenes. However, the same level of overexpression blocked liver regeneration, while let-7 deletion enhanced it, demonstrating that distinct let-7 levels can mediate desirable phenotypes. let-7 dependent regeneration phenotypes resulted from influences on the insulin-PI3K-mTOR pathway. We found that chronic high-dose let-7 overexpression caused liver damage and degeneration, paradoxically leading to tumorigenesis. These dose-dependent roles for let-7 in tissue repair and tumorigenesis rationalize the tight regulation of this microRNA in development, and have important implications for let-7 based therapeutics. DOI: http://dx.doi.org/10.7554/eLife.09431.001 PMID:26445246

Thrombospondin-1 expression may be implicated in liver atrophic mechanism due to obstructed portal venous flow.

Science.gov (United States)

Hayashi, Hiromitsu; Kuroki, Hideyuki; Higashi, Takaaki; Takeyama, Hideaki; Yokoyama, Naomi; Okabe, Hirohisa; Nitta, Hidetoshi; Beppu, Toru; Takamori, Hiroshi; Baba, Hideo

2017-07-01

Liver is an amazing organ that can undergo regenerative and atrophic changes inversely, depending on blood flow conditions. Although the regenerative mechanism has been extensively studied, the atrophic mechanism remains to be elucidated. To assess the molecular mechanism of liver atrophy due to reduced portal blood flow, we analyzed the gene expressions between atrophic and hypertrophic livers induced by portal vein embolization in three human liver tissues using microarray analyses. Thrombospondin (TSP)-1 is an extracellular protein and a negative regulator of liver regeneration through its activation of the transforming growth factor-β/Smad signaling pathway. TSP-1 was extracted as the most upregulated gene in atrophic liver compared to hypertrophic liver due to portal flow obstruction in human. Liver atrophic and hypertrophic changes were confirmed by HE and proliferating cell nuclear antigen staining and terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling. In an in vivo model with portal ligation, TSP-1 and phosphorylated Smad2 expression were continuously induced at 6 h and thereafter in the portal ligated liver, whereas the induction was transient at 6 h in the portal non-ligated liver. Indeed, while cell proliferation represented by proliferating cell nuclear antigen expression at 48 h was induced in the portal ligated liver, the sinusoidal dilatation and hepatocyte cell death with terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling was detectable at 48 h in the portal ligated liver. Obstructed portal flow induces persistent TSP-1 expression and transforming growth factor-β/Smad signal activation in atrophic liver. Thrombospondin-1 may be implicated in the liver atrophic change due to obstructed portal flow as a pro-atrophic factor. © 2016 The Japan Society of Hepatology.

Endothelial-regenerating cells: an expanding universe.

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Steinmetz, Martin; Nickenig, Georg; Werner, Nikos

2010-03-01

Atherosclerosis is the most common cause for cardiovascular diseases and is based on endothelial dysfunction. A growing body of evidence suggests the contribution of bone marrow-derived endothelial progenitor cells, monocytic cells, and mature endothelial cells to vessel formation and endothelial rejuvenation. To this day, various subsets of these endothelial-regenerating cells have been identified according to cellular origin, phenotype, and properties in vivo and in vitro. However, the definition and biology, especially of endothelial progenitor cells, is complex and under heavy debate. In this review, we focus on current definitions of endothelial progenitor cells, highlight the clinical relevance of endothelial-regenerating cells, and provide new insights into cell-cell interactions involved in endothelial cell rejuvenation.

Potential Use of Stem Cells for Kidney Regeneration

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Takashi Yokoo

2011-01-01

Full Text Available Significant advances have been made in stem cell research over the past decade. A number of nonhematopoietic sources of stem cells (or progenitor cells have been identified, including endothelial stem cells and neural stem cells. These discoveries have been a major step toward the use of stem cells for potential clinical applications of organ regeneration. Accordingly, kidney regeneration is currently gaining considerable attention to replace kidney dialysis as the ultimate therapeutic strategy for renal failure. However, due to anatomic complications, the kidney is believed to be the hardest organ to regenerate; it is virtually impossible to imagine such a complicated organ being completely rebuilt from pluripotent stem cells by gene or chemical manipulation. Nevertheless, several groups are taking on this big challenge. In this manuscript, current advances in renal stem cell research are reviewed and their usefulness for kidney regeneration discussed. We also reviewed the current knowledge of the emerging field of renal stem cell biology.

Rac1 selective activation improves retina ganglion cell survival and regeneration.

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Erika Lorenzetto

Full Text Available In adult mammals, after optic nerve injury, retinal ganglion cells (RGCs do not regenerate their axons and most of them die by apoptosis within a few days. Recently, several strategies that activate neuronal intracellular pathways were proposed to prevent such degenerative processes. The rho-related small GTPase Rac1 is part of a complex, still not fully understood, intracellular signaling network, mediating in neurons many effects, including axon growth and cell survival. However, its role in neuronal survival and regeneration in vivo has not yet been properly investigated. To address this point we intravitreally injected selective cell-penetrating Rac1 mutants after optic nerve crush and studied the effect on RGC survival and axonal regeneration. We injected two well-characterized L61 constitutively active Tat-Rac1 fusion protein mutants, in which a second F37A or Y40C mutation confers selectivity in downstream signaling pathways. Results showed that, 15 days after crush, both mutants were able to improve survival and to prevent dendrite degeneration, while the one harboring the F37A mutation also improved axonal regeneration. The treatment with F37A mutant for one month did not improve the axonal elongation respect to 15 days. Furthermore, we found an increase of Pak1 T212 phosphorylation and ERK1/2 expression in RGCs after F37A treatment, whereas ERK1/2 was more activated in glial cells after Y40C administration. Our data suggest that the selective activation of distinct Rac1-dependent pathways could represent a therapeutic strategy to counteract neuronal degenerative processes in the retina.

The muscle stem cell niche : regulation of satellite cells during regeneration

NARCIS (Netherlands)

Boonen, K.J.M.; Post, M.J.

2008-01-01

Satellite cells are considered to be adult skeletal muscle stem cells. Their ability to regenerate large muscle defects is highly dependent on their specific niche. When these cells are cultured in vitro, the loss of this niche leads to a loss of proliferative capacity and defective regeneration

Transection of the hepatic parenchyma associated or not with the contralateral portal vein branch ligature and its effect in liver regeneration.

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Wiederkehr, Henrique de Aguiar; Wiederkehr, Julio Cesar; Collaço, Luiz Martins; Sousa, Eros Luiz de; Salvalaggio, Paolo; Carvalho, Caroline Aragão de; Wiederkehr, Barbara de Aguiar; Marques, Camila Aparecida Moraes; Rosa, Francielle França da; Nanni, Felipe de Negreiros; Fuchs, Taíse

2017-01-01

To analyze the influence of portal vein ligation in hepatic regeneration by immunohistochemical criteria. Ten pigs divided into two groups of five animals underwent hepatectomy in two stages, and the groups were differentiated by ligation or not of the left portal vein tributary, which is responsible for vascularization of the left lateral and medial lobes of the pig liver. Five days after the procedure, the animals underwent liver biopsies for further analysis of histological and immunohistochemical with marker Ki67. The group submitted to hepatectomy with vascular ligation showed an increase of approximately 4% of hepatocytes in regeneration status, as well as a greater presence of Kupffer and inflammatory cells as compared to control. As a result of positive cell replication observed through the Ki67 marker, we can suspect that the ligation of a tributary of the portal vein associated with liver resection promoted a greater stimulus of liver regeneration when compared to liver resection alone. Analisar a influência da ligadura da tributária da veia porta no estímulo regenerativo hepático por meio de critérios imuno-histoquímicos. Dez suínos, divididos em dois grupos de cinco animais, foram submetidos à hepatectomia em dois estágios, sendo que os grupos foram diferenciados pela ligadura ou não da tributária da veia porta, responsável pela vascularização dos lobos lateral e medial esquerdos do fígado do suíno. Cinco dias após o procedimento, os animais foram reabordados para retirada de amostras hepáticas para posterior análise de histológica e imunoistoquímica com o marcador Ki67. O grupo submetido à hepatectomia com ligadura vascular apresentou incremento de 4% aproximadamente de hepatócitos em processo de regeneração, bem como grande número de células de Kupffer e células inflamatórias, quando comparado ao controle. Em virtude da análise positiva da replicação celular observada por meio do marcador Ki67, pode-se observar que a

NKT cells act through third party bone marrow-derived cells to suppress NK cell activity in the liver and exacerbate hepatic melanoma metastases.

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Sadegh, Leila; Chen, Peter W; Brown, Joseph R; Han, Zhiqiang; Niederkorn, Jerry Y

2015-09-01

Uveal melanoma (UM) is the most common intraocular tumor in adults and liver metastasis is the leading cause of death in UM patients. We have previously shown that NKT cell-deficient mice develop significantly fewer liver metastases from intraocular melanomas than do wild-type (WT) mice. Here, we examine the interplay between liver NKT cells and NK cells in resistance to liver metastases from intraocular melanomas. NKT cell-deficient CD1d(-/-) mice and WT C57BL/6 mice treated with anti-CD1d antibody developed significantly fewer liver metastases than WT mice following either intraocular or intrasplenic injection of B16LS9 melanoma cells. The increased number of metastases in WT mice was associated with reduced liver NK cytotoxicity and decreased production of IFN-γ. However, liver NK cell-mediated cytotoxic activity was identical in non-tumor bearing NKT cell-deficient mice and WT mice, indicating that liver metastases were crucial for the suppression of liver NK cells. Depressed liver NK cytotoxicity in WT mice was associated with production of IL-10 by bone marrow-derived liver cells that were neither Kupffer cells nor myeloid-derived suppressor cells and by increased IL-10 receptor expression on liver NK cells. IL-10(-/-) mice had significantly fewer liver metastases than WT mice, but were not significantly different from NKT cell-deficient mice. Thus, development of melanoma liver metastases is associated with upregulation of IL-10 in the liver and an elevated expression of IL-10 receptor on liver NK cells. This impairment of liver NK activity is NKT cell-dependent and only occurs in hosts with melanoma liver metastases. © 2015 UICC.

Cell Pleomorphism and Cytoskeleton Disorganization in Human Liver Cancer.

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Cheng, Chiung-Chi; Lai, Yen-Chang Clark; Lai, Yih-Shyong; Chao, Wei-Ting; Tseng, Yu-Hui; Hsu, Yung-Hsiang; Chen, You-Yin; Liu, Yi-Hsiang

Nucleoskeleton maintains the framework of a cell nucleus that is required for a variety of nuclear functions. However, the nature of nucleoskeleton structure has not been yet clearly elucidated due to microscopy visualization limitations. Plectin, a nuclear pore-permeable component of cytoskeleton, exhibits a role of cross-linking between cytoplasmic intermediate filaments and nuclear lamins. Presumably, plectin is also a part of nucleoskeleton. Previously, we demonstrated that pleomorphism of hepatoma cells is the consequence of cytoskeletal changes mediated by plectin deficiency. In this study, we applied a variety of technologies to detect the cytoskeletons in liver cells. The images of confocal microscopy did not show the existence of plectin, intermediate filaments, microfilaments and microtubules in hepatic nuclei. However, in the isolated nuclear preparation, immunohistochemical staining revealed positive results for plectin and cytoskeletal proteins that may contribute to the contamination derived from cytoplasmic residues. Therefore, confocal microscopy provides a simple and effective technology to observe the framework of nucleoskeleton. Accordingly, we verified that cytoskeletons are not found in hepatic cell nuclei. Furthermore, the siRNA-mediated knockdown of plectin in liver cells leads to collapsed cytoskeleton, cell transformation and pleomorphic nuclei. Plectin and cytoskeletons were not detected in the nuclei of liver cells compared to the results of confocal microscopy. Despite the absence of nuclear plectin and cytoskeletal filaments, the evidence provided support that nuclear pleomorphism of cancer cells is correlated with the cytoplasmic disorganization of cytoskeleton. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Robust regeneration protocol for the Agrobacterium tumefaciens mediated transformation of Solanum tuberosum

International Nuclear Information System (INIS)

Abbasi, A.; Bilal, M.; Hussain, J.; Shah, M. M.; Hassan, A.

2016-01-01

Plant genetic transformation requires robust regeneration system. Plant growth regulators (PGRs) such as cytokinins (CKs) play a pivotal role in organogenesis; however, CKs are the most expensive PGRs. In the current study, an efficient yet economical protocol for regeneration of potato plant was developed. Stem inter-nodal and leaf explants were cultured on different regeneration media supplemented with varying concentration of different CKs such as kinetin and zeatin. Murashige- Skoog media added with zeatin (1, 1.5 mg/L) was designated as RZ1, RZ1.5, respectively or kinetin (1.5, 2 mg/L) was designated as RK1.5 and RK2, respectively, however, concentrations of other hormones such as NAA (1-Naphthaleneacetic acid) and GA3 (Gibberellic acid A3) were kept same. RZ1 and RZ1.5 gave significantly better Results as compared to RK-type media in all aspects studied such as callus initiation, days to first shoot emergence, number of shoots per explants. RZ1 medium was then selected as regeneration media for Agrobacterium-mediated transformation of potato plants with cyanobacterial phosphoenol pyruvate carboxylase gene, which provided multiple putative transformants on selection media. The transformants were further confirmed through PCR. The current protocol is found to be cost effective and efficient for the regeneration of Solanum tuberosum and can be successfully implied for the Agrobacterium-mediated transformation. (author)

Identification and Characterization of Mesenchymal-Epithelial Progenitor-Like Cells in Normal and Injured Rat Liver

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Liu, Daqing; Yovchev, Mladen I.; Zhang, Jinghang; Alfieri, Alan A.; Tchaikovskaya, Tatyana; Laconi, Ezio; Dabeva, Mariana D.

2016-01-01

In normal rat liver, thymocyte antigen 1 (Thy1) is expressed in fibroblasts/myofibroblasts and in some blood progenitor cells. Thy1-expressing cells also accumulate in the liver during impaired liver regeneration. The origin and nature of these cells are not well understood. By using RT-PCR analysis and immunofluorescence microscopy, we describe the presence of rare Thy1+ cells in the liver lobule of normal animals, occasionally forming small collections of up to 20 cells. These cells constitute a small portion (1.7% to 1.8%) of nonparenchymal cells and reveal a mixed mesenchymal-epithelial phenotype, expressing E-cadherin, cytokeratin 18, and desmin. The most potent mitogens for mesenchymal-epithelial Thy1+ cells in vitro are the inflammatory cytokines interferon γ, IL-1, and platelet-derived growth factor-BB, which are not produced by Thy1+ cells. Thy1+ cells express all typical mesenchymal stem cell and hepatic progenitor cell markers and produce growth factor and cytokine mRNA (Hgf, Il6, Tgfa, and Tweak) for proteins that maintain oval cell growth and differentiation. Under appropriate conditions, mesenchymal-epithelial cells differentiate in vitro into hepatocyte-like cells. In this study, we show that the adult rat liver harbors a small pool of endogenous mesenchymal-epithelial cells not recognized previously. In the quiescent state, these cells express both mesenchymal and epithelial cell markers. They behave like hepatic stem cells/progenitors with dual phenotype, exhibiting high plasticity and long-lasting proliferative activity. PMID:25447047

Endogenous n-3 polyunsaturated fatty acids attenuate T cell-mediated hepatitis via autophagy activation

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Yanli Li

2016-09-01

Full Text Available Omega-3 polyunsaturated fatty acids (n-3 PUFAs exert anti-inflammatory effects in several liver disorders, including cirrhosis, acute liver failure, and fatty liver disease. To date, little is known about their role in immune-mediated liver diseases. In this study, we used fat-1 transgenic mice rich in endogenous n-3 PUFAs to examine the role of n-3 PUFAs in immune-mediated liver injury. Concanavalin A (Con A was administered intravenously to wild-type (WT and fat-1 transgenic mice to induce T cell-mediated hepatitis. Reduced liver damage was shown in Con A-administrated fat-1 transgenic mice, as evidenced by decreased mortality, attenuated hepatic necrosis, lessened serum alanine aminotransferase (ALT activity, and inhibited production of pro-inflammatory cytokines (e.g. TNF-α, IL-6, IL-17A and IFN-γ. In vivo and in vitro studies demonstrated that n-3 PUFAs significantly inhibited the activation of hepatic T cells and the differentiation of Th1 cells after Con A challenge. Further studies showed that n-3 PUFAs markedly increased autophagy level in Con A-treated fat-1 T cells compared with the WT counterparts. Blocking hepatic autophagy activity with chloroquine diminished the differences in T cell activation and liver injury between Con A-injected WT and fat-1 transgenic mice. We conclude that n-3 PUFAs limit Con A-induced hepatitis via an autophagy-dependent mechanism, and could be exploited as a new therapeutic approach for autoimmune hepatitis.

CD147 promotes liver fibrosis progression via VEGF-A/VEGFR2 signalling-mediated cross-talk between hepatocytes and sinusoidal endothelial cells.

Science.gov (United States)

Yan, Zhaoyong; Qu, Kai; Zhang, Jing; Huang, Qichao; Qu, Ping; Xu, Xinsen; Yuan, Peng; Huang, Xiaojun; Shao, Yongping; Liu, Chang; Zhang, Hongxin; Xing, Jinliang

2015-10-01

Although previous evidence indicates close involvement of CD147 in the pathogenesis of liver fibrosis, the underlying molecular mechanisms and its therapeutic value remain largely unknown. In the present study, we investigated the biological roles of CD147 in liver fibrosis and assessed its therapeutic value as a target molecule in the CCl4-induced liver fibrosis mouse model. We found that CD147 was highly expressed in both hepatocytes and SECs (sinusoidal endothelial cells) in fibrotic liver tissues. Additionally, it was significantly associated with the fibrosis stage. TGF-β1 (transforming growth factor β1) was found to be mainly responsible for the up-regulation of CD147. Bioinformatic and experimental data suggest a functional link between CD147 expression and VEGF-A (vascular endothelial growth factor A)/VEGR-2 (VEGF receptor 2) signalling-mediated angiogenesis in fibrotic liver tissues. Furthermore, we observed that the CD147-induced activation of the PI3K (phosphoinositide 3-kinase)/Akt signalling pathway promotes the production of VEGF-A in hepatocytes and expression of VEGFR-2 in SECs, which was found to enhance the angiogenic capability of SECs. Finally, our data indicate that blocking of CD147 using an mAb (monoclonal antibody) attenuated liver fibrosis progression via inhibition of VEGF-A/VEGFR-2 signalling and subsequent amelioration of microvascular abnormality in the CCl4-induced mouse model. Our findings suggest a novel functional mechanism that CD147 may promote liver fibrosis progression via inducing the VEGF-A/VEGFR-2 signalling pathway-mediated cross-talk between hepatocytes and SECs. New strategies based on the intervention of CD147 can be expected for prevention of liver fibrosis. © 2015 Authors; published by Portland Press Limited.

Feathers and fins: non-mammalian models for hair cell regeneration.

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Brignull, Heather R; Raible, David W; Stone, Jennifer S

2009-06-24

Death of mechanosensory cells in the inner ear results in two profound disabilities: hearing loss and balance disorders. Although mammals lack the capacity to regenerate hair cells, recent studies in mice and other rodents have offered valuable insight into strategies for stimulating hair cell regeneration in mammals. Investigations of model organisms that retain the ability to form new hair cells after embryogenesis, such as fish and birds, are equally important and have provided clues as to the cellular and molecular mechanisms that may block hair cell regeneration in mammals. Here, we summarize studies on hair cell regeneration in the chicken and the zebrafish, discuss specific advantages of each model, and propose future directions for the use of non-mammalian models in understanding hair cell regeneration.

T cells infiltrate the liver and kill hepatocytes in HLA-B(∗)57:01-associated floxacillin-induced liver injury.

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Wuillemin, Natascha; Terracciano, Luigi; Beltraminelli, Helmut; Schlapbach, Christoph; Fontana, Stefano; Krähenbühl, Stephan; Pichler, Werner J; Yerly, Daniel

2014-06-01

Drug-induced liver injury is a major safety issue. It can cause severe disease and is a common cause of the withdrawal of drugs from the pharmaceutical market. Recent studies have identified the HLA-B(∗)57:01 allele as a risk factor for floxacillin (FLUX)-induced liver injury and have suggested a role for cytotoxic CD8(+) T cells in the pathomechanism of liver injury caused by FLUX. This study aimed to confirm the importance of FLUX-reacting cytotoxic lymphocytes in the pathomechanism of liver injury and to dissect the involved mechanisms of cytotoxicity. IHC staining of a liver biopsy from a patient with FLUX-induced liver injury revealed periportal inflammation and the infiltration of cytotoxic CD3(+) CD8(+) lymphocytes into the liver. The infiltration of cytotoxic lymphocytes into the liver of a patient with FLUX-induced liver injury demonstrates the importance of FLUX-reacting T cells in the underlying pathomechanism. Cytotoxicity of FLUX-reacting T cells from 10 HLA-B(∗)57:01(+) healthy donors toward autologous target cells and HLA-B(∗)57:01-transduced hepatocytes was analyzed in vitro. Cytotoxicity of FLUX-reacting T cells was concentration dependent and required concentrations in the range of peak serum levels after FLUX administration. Killing of target cells was mediated by different cytotoxic mechanisms. Our findings emphasize the role of the adaptive immune system and especially of activated drug-reacting T cells in human leukocyte antigen-associated, drug-induced liver injury. Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Challenges of stem cell-based pulp and dentin regeneration: a clinical perspective.

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Huang, George T-J; Al-Habib, Mey; Gauthier, Philippe

2013-03-01

There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or completely in the root canal space with apical openings of 0.7-3.0 mm using dental pulp stem cells, including stem cells from apical papilla (SCAP) and subpopulations of pulp stem cells. Bone marrow mesenchymal stem cells (BMMSCs) and adipose tissue-derived MSCs (ADMSCs) have also been shown to regenerate pulp-like tissue. In contrast, the cell-free approach has not produced convincing evidence on pulp regeneration. However, one crucial concept has not been considered nor defined in the field of pulp/dentin regeneration and that is the critical size defect of dentin and pulp. Without such consideration and definition, it is difficult to predict or anticipate the extent of cell-free pulp regeneration that would occur. By reasoning, cell-free therapy is unlikely to regenerate an organ/tissue after total loss. Similarly, after a total loss of pulp, it is unlikely to regenerate without using exogenously introduced cells. A cell homing approach may provide a limited amount of tissue regeneration. Although stem cell-based pulp/dentin regeneration has shown great promise, clinical trials are difficult to launch at present. This article will address several issues that challenge and hinder the clinical applications of pulp/dentin regeneration which need to be overcome before stem cell-based pulp/dentin regeneration can occur in the clinic.

Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration.

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Lee, Sang Goo; Huang, Mingqian; Obholzer, Nikolaus D; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A; Megason, Sean G; Li, Huawei; Chen, Zheng-Yi

2016-01-01

Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration.

Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation

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Nagata, Yosuke, E-mail: cynagata@mail.ecc.u-tokyo.ac.jp; Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

2014-08-01

Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor. - Highlights: • EGF in combination with insulin induces proliferation of quiescent C2C12 cells. • Sphingosine kinase activity increases when reserve cells are stimulated with EGF. • EGF-induced activation of reserve cells is dependent on sphingosine kinase and ERK. • The S1P receptor S1P2 is involved in EGF-induced reserve cell activation. • EGF-induced reserve cell activation is mediated by S1P and its

Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation

International Nuclear Information System (INIS)

Nagata, Yosuke; Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

2014-01-01

Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor. - Highlights: • EGF in combination with insulin induces proliferation of quiescent C2C12 cells. • Sphingosine kinase activity increases when reserve cells are stimulated with EGF. • EGF-induced activation of reserve cells is dependent on sphingosine kinase and ERK. • The S1P receptor S1P2 is involved in EGF-induced reserve cell activation. • EGF-induced reserve cell activation is mediated by S1P and its

Proliferative human cell sources applied as biocomponent in bioartificial livers: a review

NARCIS (Netherlands)

Nibourg, Geert A. A.; Chamuleau, Robert A. F. M.; van Gulik, Thomas M.; Hoekstra, Ruurdtje

2012-01-01

Introduction: Bioartificial livers (BALs) are urgently needed to bridge severe liver failure patients to liver transplantation or liver regeneration. When based on primary hepatocytes, their efficacy has been shown in animal experiments and their safety was confirmed in clinical trials. However, a

Cancer-related aspects of regeneration research: a review

International Nuclear Information System (INIS)

Donaldson, D.J.; Mason, J.M.

1975-01-01

Tissue regeneration is simply the replacement of lost cells of a tissue by those remaining. Epimorphic regeneration involves dedifferentiation of many tissues and their organization into a blastema which eventually differentiates into the missing part, usually an appendage. A detailed comparison of the cell membrane changes occurring in epimorphic regeneration, tissue regeneration and cancer can contribute to greater understanding of the differences between normal and tumor cells. Further, there is evidence that epimorphic regeneration fields may in some instances suppress tumor induction and control existing tumors. This influence may be mediated by bioelectric fields, which are ubiquitous in nature and appear to control many cellular events. Disruption of these bioelectric fields suppresses epimorphic regeneration and may lead to cancer in mammals, while applied electric fields alter regenerative events and cause tumor regression. Studies on x-radioinduced regeneration suppression in relation to mutagenesis are also reviewed

Biomaterials and Culture Technologies for Regenerative Therapy of Liver Tissue.

Science.gov (United States)

Perez, Roman A; Jung, Cho-Rok; Kim, Hae-Won

2017-01-01

Regenerative approach has emerged to substitute the current extracorporeal technologies for the treatment of diseased and damaged liver tissue. This is based on the use of biomaterials that modulate the responses of hepatic cells through the unique matrix properties tuned to recapitulate regenerative functions. Cells in liver preserve their phenotype or differentiate through the interactions with extracellular matrix molecules. Therefore, the intrinsic properties of the engineered biomaterials, such as stiffness and surface topography, need to be tailored to induce appropriate cellular functions. The matrix physical stimuli can be combined with biochemical cues, such as immobilized functional groups or the delivered actions of signaling molecules. Furthermore, the external modulation of cells, through cocultures with nonparenchymal cells (e.g., endothelial cells) that can signal bioactive molecules, is another promising avenue to regenerate liver tissue. This review disseminates the recent approaches of regenerating liver tissue, with a focus on the development of biomaterials and the related culture technologies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Establishment of a D-galactosamine/lipopolysaccharide induced acute-on-chronic liver failure model in rats].

Science.gov (United States)

Liu, Xu-hua; Chen, Yu; Wang, Tai-ling; Lu, Jun; Zhang, Li-jie; Song, Chen-zhao; Zhang, Jing; Duan, Zhong-ping

2007-10-01

To establish a practical and reproducible animal model of human acute-on-chronic liver failure for further study of the pathophysiological mechanism of acute-on-chronic liver failure and for drug screening and evaluation in its treatment. Immunological hepatic fibrosis was induced by human serum albumin in Wistar rats. In rats with early-stage cirrhosis (fibrosis stage IV), D-galactosamine and lipopolysaccharide were administered. Mortality and survival time were recorded in 20 rats. Ten rats were sacrificed at 4, 8, and 12 hours. Liver function tests and plasma cytokine levels were measured after D-galactosamine/lipopolysaccharide administration and liver pathology was studied. Cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Most of the rats treated with human albumin developed cirrhosis and fibrosis, and 90% of them died from acute liver failure after administration of D-galactosamine/lipopolysaccharide, with a mean survival time of (16.1+/-3.7) hours. Liver histopathology showed massive or submassive necrosis of the regenerated nodules, while fibrosis septa were intact. Liver function tests were compatible with massive necrosis of hepatocytes. Plasma level of TNFalpha increased significantly, parallel with the degree of the hepatocytes apoptosis. Plasma IL-10 levels increased similarly as seen in patients with acute-on-chronic liver failure. We established an animal model of acute-on-chronic liver failure by treating rats with human serum albumin and later with D-galactosamine and lipopolysaccharide. TNFalpha-mediated liver cell apoptoses plays a very important role in the pathogenesis of acute liver failure.

CRISPR-Mediated Genomic Deletion of Sox2 in the Axolotl Shows a Requirement in Spinal Cord Neural Stem Cell Amplification during Tail Regeneration

Directory of Open Access Journals (Sweden)

Ji-Feng Fei

2014-09-01

Full Text Available The salamander is the only tetrapod that functionally regenerates all cell types of the limb and spinal cord (SC and thus represents an important regeneration model, but the lack of gene-knockout technology has limited molecular analysis. We compared transcriptional activator-like effector nucleases (TALENs and clustered regularly interspaced short palindromic repeats (CRISPRs in the knockout of three loci in the axolotl and find that CRISPRs show highly penetrant knockout with less toxic effects compared to TALENs. Deletion of Sox2 in up to 100% of cells yielded viable F0 larvae with normal SC organization and ependymoglial cell marker expression such as GFAP and ZO-1. However, upon tail amputation, neural stem cell proliferation was inhibited, resulting in spinal-cord-specific regeneration failure. In contrast, the mesodermal blastema formed normally. Sox3 expression during development, but not regeneration, most likely allowed embryonic survival and the regeneration-specific phenotype. This analysis represents the first tissue-specific regeneration phenotype from the genomic deletion of a gene in the axolotl.

Gal-3 regulates the capacity of dendritic cells to promote NKT-cell-induced liver injury.

Science.gov (United States)

Volarevic, Vladislav; Markovic, Bojana Simovic; Bojic, Sanja; Stojanovic, Maja; Nilsson, Ulf; Leffler, Hakon; Besra, Gurdyal S; Arsenijevic, Nebojsa; Paunovic, Verica; Trajkovic, Vladimir; Lukic, Miodrag L

2015-02-01

Galectin-3 (Gal-3), an endogenous lectin, exhibits pro- and anti-inflammatory effects in various disease conditions. In order to explore the role of Gal-3 in NKT-cell-dependent pathology, we induced hepatitis in C57BL/6 WT and Gal-3-deficient mice by using specific ligand for NKT cells: α-galactosylceramide, glycolipid Ag presented by CD1d. The injection of α-galactosylceramide significantly enhanced expression of Gal-3 in liver NKT and dendritic cells (DCs). Genetic deletion or selective inhibition of Gal-3 (induced by Gal-3-inhibitor TD139) abrogated the susceptibility to NKT-cell-dependent hepatitis. Blood levels of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-12) and their production by liver DCs and NKT cells were also downregulated. Genetic deletion or selective inhibition of Gal-3 alleviated influx of inflammatory CD11c(+) CD11b(+) DCs in the liver and favored tolerogenic phenotype and IL-10 production of liver NKT and DCs. Deletion of Gal-3 attenuated the capacity of DCs to support liver damage in the passive transfer experiments and to produce pro-inflammatory cytokines in vitro. Gal-3-deficient DCs failed to optimally stimulate production of pro-inflammatory cytokines in NKT cells, in vitro and in vivo. In conclusion, Gal-3 regulates the capacity of DCs to support NKT-cell-mediated liver injury, playing an important pro-inflammatory role in acute liver injury. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recellularization of rat liver: An in vitro model for assessing human drug metabolism and liver biology.

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Matthew J Robertson

Full Text Available Liver-like organoids that recapitulate the complex functions of the whole liver by combining cells, scaffolds, and mechanical or chemical cues are becoming important models for studying liver biology and drug metabolism. The advantages of growing cells in three-dimensional constructs include enhanced cell-cell and cell-extracellular matrix interactions and preserved cellular phenotype including, prevention of de-differentiation. In the current study, biomimetic liver constructs were made via perfusion decellularization of rat liver, with the goal of maintaining the native composition and structure of the extracellular matrix. We optimized our decellularization process to produce liver scaffolds in which immunogenic residual DNA was removed but glycosaminoglycans were maintained. When the constructs were recellularized with rat or human liver cells, the cells remained viable, capable of proliferation, and functional for 28 days. Specifically, the cells continued to express cytochrome P450 genes and maintained their ability to metabolize a model drug, midazolam. Microarray analysis showed an upregulation of genes involved in liver regeneration and fibrosis. In conclusion, these liver constructs have the potential to be used as test beds for studying liver biology and drug metabolism.

HMGB1 and Extracellular Histones Significantly Contribute to Systemic Inflammation and Multiple Organ Failure in Acute Liver Failure

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Runkuan Yang

2017-01-01

Full Text Available Acute liver failure (ALF is the culmination of severe liver cell injury from a variety of causes. ALF occurs when the extent of hepatocyte death exceeds the hepatic regenerative capacity. ALF has a high mortality that is associated with multiple organ failure (MOF and sepsis; however, the underlying mechanisms are still not clear. Emerging evidence shows that ALF patients/animals have high concentrations of circulating HMGB1, which can contribute to multiple organ injuries and mediate gut bacterial translocation (BT. BT triggers/induces systemic inflammatory responses syndrome (SIRS, which can lead to MOF in ALF. Blockade of HMGB1 significantly decreases BT and improves hepatocyte regeneration in experimental acute fatal liver injury. Therefore, HMGB1 seems to be an important factor that links BT and systemic inflammation in ALF. ALF patients/animals also have high levels of circulating histones, which might be the major mediators of systemic inflammation in patients with ALF. Extracellular histones kill endothelial cells and elicit immunostimulatory effect to induce multiple organ injuries. Neutralization of histones can attenuate acute liver, lung, and brain injuries. In conclusion, HMGB1 and histones play a significant role in inducing systemic inflammation and MOF in ALF.

HMGB1 and Extracellular Histones Significantly Contribute to Systemic Inflammation and Multiple Organ Failure in Acute Liver Failure.

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Yang, Runkuan; Zou, Xiaoping; Tenhunen, Jyrki; Tønnessen, Tor Inge

2017-01-01

Acute liver failure (ALF) is the culmination of severe liver cell injury from a variety of causes. ALF occurs when the extent of hepatocyte death exceeds the hepatic regenerative capacity. ALF has a high mortality that is associated with multiple organ failure (MOF) and sepsis; however, the underlying mechanisms are still not clear. Emerging evidence shows that ALF patients/animals have high concentrations of circulating HMGB1, which can contribute to multiple organ injuries and mediate gut bacterial translocation (BT). BT triggers/induces systemic inflammatory responses syndrome (SIRS), which can lead to MOF in ALF. Blockade of HMGB1 significantly decreases BT and improves hepatocyte regeneration in experimental acute fatal liver injury. Therefore, HMGB1 seems to be an important factor that links BT and systemic inflammation in ALF. ALF patients/animals also have high levels of circulating histones, which might be the major mediators of systemic inflammation in patients with ALF. Extracellular histones kill endothelial cells and elicit immunostimulatory effect to induce multiple organ injuries. Neutralization of histones can attenuate acute liver, lung, and brain injuries. In conclusion, HMGB1 and histones play a significant role in inducing systemic inflammation and MOF in ALF.

Reactivation of X-irradiated cell material during limb regeneration in Urodeles Amphibians

International Nuclear Information System (INIS)

Desselle, J.C.

1979-10-01

In amputated members irradiated with X-rays the regeneration power is inhibited. This power is restored by grafts of healthy tissue in the irradiated members. The origin of the cell material of the restored regeneration blastema has been studied by an original labelling technique. The different amounts of DNA in the graft cells and those of the stump mark the graft cells during the regeneration process. It was shown that the graft causes a reactivation of the inhibited stump cells and the reactivation stages are the same as the activation stages of the member regenerating normally. It was also established that during restored regeneration the cell material implanted in the irradiated members contributes, by the 160th day of regeneration, 4.5% of the cartilaginous regenerate cells and 12% of the muscle cells. All the other regenerate cells are supplied by the cells of the stump; these are reactivated and together with the activated graft cells lead to the restitution of the amputated member [fr

Liver Cell Culture Devices

NARCIS (Netherlands)

Andria, B.; Bracco, A.; Cirino, G.; Chamuleau, R. A. F. M.

2010-01-01

In the last 15 years many different liver cell culture devices, consisting of functional liver cells and artificial materials, have been developed. They have been devised for numerous different applications, such as temporary organ replacement (a bridge to liver transplantation or native liver

HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver

DEFF Research Database (Denmark)

Ding, Bi-Sen; Liu, Catherine H; Sun, Yue

2016-01-01

Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 ...

MET Signaling Mediates Intestinal Crypt-Villus Development, Regeneration, and Adenoma Formation and Is Promoted by Stem Cell CD44 Isoforms.

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Joosten, Sander P J; Zeilstra, Jurrit; van Andel, Harmen; Mijnals, R Clinton; Zaunbrecher, Joost; Duivenvoorden, Annet A M; van de Wetering, Marc; Clevers, Hans; Spaargaren, Marcel; Pals, Steven T

2017-10-01

/Met fl/fl /LacZ mice. Lgr5 Creert2 /Met fl/fl /LacZ mice had impaired regeneration of MET-deficient ISCs. Adenoma organoids stimulated with EGF or HGF expanded to almost twice the size of nonstimulated organoids. MET-deficient adenoma organoids did not respond to HGF stimulation, but did respond to EGF. ISC-specific disruption of Met (Lgr5 Creert2 /Met fl/fl /Apc fl/fl mice) caused a twofold increase in apoptosis in microadenomas, resulting in an approximately 50% reduction of microadenoma numbers and significantly reduced average adenoma size. Total epithelial disruption of Met (Ah Cre /Met fl/fl /Apc fl/+ mice) resulted in an approximate 50% reduction in (micro)adenoma numbers. Intestinal crypts from Cd44 -/- mice did not expand to the same extent as crypts from Cd44 +/+ mice on stimulation with HGF, but had the same response to EGF. The negative effect on HGF-mediated growth was overcome by expression of CD44v4-10, but not by CD44s. Similarly, HGF-mediated expansion of adenoma organoids required CD44v4-10. In studies of intestinal organoid cultures and mice with inducible deletion of MET, we found HGF receptor signaling to regulate intestinal homeostasis and regeneration, as well as adenoma formation. These activities of MET are promoted by the stem cell CD44 isoform CD44v4-10. Our findings provide rationale for targeting signaling via MET and CD44 during anti-EGF receptor therapy of patients with colorectal cancer or in patients resistant to EGF receptor inhibitors. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

Sensory hair cell regeneration in the zebrafish lateral line.

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Lush, Mark E; Piotrowski, Tatjana

2014-10-01

Damage or destruction of sensory hair cells in the inner ear leads to hearing or balance deficits that can be debilitating, especially in older adults. Unfortunately, the damage is permanent, as regeneration of the inner ear sensory epithelia does not occur in mammals. Zebrafish and other non-mammalian vertebrates have the remarkable ability to regenerate sensory hair cells and understanding the molecular and cellular basis for this regenerative ability will hopefully aid us in designing therapies to induce regeneration in mammals. Zebrafish not only possess hair cells in the ear but also in the sensory lateral line system. Hair cells in both organs are functionally analogous to hair cells in the inner ear of mammals. The lateral line is a mechanosensory system found in most aquatic vertebrates that detects water motion and aids in predator avoidance, prey capture, schooling, and mating. Although hair cell regeneration occurs in both the ear and lateral line, most research to date has focused on the lateral line due to its relatively simple structure and accessibility. Here we review the recent discoveries made during the characterization of hair cell regeneration in zebrafish. Copyright © 2014 Wiley Periodicals, Inc.

SENSORY HAIR CELL REGENERATION IN THE ZEBRAFISH LATERAL LINE

Science.gov (United States)

Lush, Mark E.; Piotrowski, Tatjana

2014-01-01

Damage or destruction of sensory hair cells in the inner ear leads to hearing or balance deficits that can be debilitating, especially in older adults. Unfortunately, the damage is permanent, as regeneration of the inner ear sensory epithelia does not occur in mammals. Zebrafish and other non-mammalian vertebrates have the remarkable ability to regenerate sensory hair cells and understanding the molecular and cellular basis for this regenerative ability will hopefully aid us in designing therapies to induce regeneration in mammals. Zebrafish not only possess hair cells in the ear but also in the sensory lateral line system. Hair cells in both organs are functionally analogous to hair cells in the inner ear of mammals. The lateral line is a mechanosensory system found in most aquatic vertebrates that detects water motion and aids in predator avoidance, prey capture, schooling and mating. Although hair cell regeneration occurs in both the ear and lateral line, most research to date has focused on the lateral line due to its relatively simple structure and accessibility. Here we review the recent discoveries made during the characterization of hair cell regeneration in zebrafish. PMID:25045019

T cell-mediated hepatitis in mice infected with lymphocytic choriomeningitis virus. Liver cell destruction by H-2 class I-restricted virus-specific cytotoxic T cells as a physiological correlate of the 51Cr-release assay

International Nuclear Information System (INIS)

Zinkernagel, R.M.; Haenseler, E.; Leist, T.; Cerny, A.; Hengartner, H.; Althage, A.

1986-01-01

A model for immunologically T cell-mediated hepatitis was established in mice infected with lymphocytic choriomeningitis virus (LCMV). The severity of hepatitis was monitored histologically and by determination of changes in serum levels of the enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), and alkaline phosphatase (AP). Kinetics of histological disease manifestations, increases of liver enzyme levels in the serum, and cytotoxic T cell activities in livers and spleens all correlated and were dependent upon several parameters: LCMV-isolate; LCMV-WE caused extensive hepatitis, LCMV-Armstrong virtually none. Virus dose. Route of infection; i.v. or i.p. infection caused hepatitis, whereas infection into the footpad did not. The general genetic background of the murine host; of the strains tested, Swiss mice and A-strain mice were more susceptible than C57BL or CBA mice; BALB/c and DBA/2 mice were least susceptible. The degree of immunocompetence of the murine host; T cell deficient nu/nu mice never developed hepatitis, whereas nu/+ or +/+ mice always did. B cell-depleted anti-IgM-treated mice developed immune-mediated hepatitis comparably or even more extensively than control mice. Local cytotoxic T cell activity; mononuclear cells isolated from livers during the period of overt hepatitis were two to five times more active than equal numbers of spleen cells. Adoptive transfer of nylon wool-nonadherent anti-Thy-1.2 and anti-Lyt-2 plus C-sensitive, anti-L3T4 plus C-resistant lymphocytes into irradiated mice preinfected with LCMV-WE caused a rapid time- and dose-dependent linear increase of serum enzyme levels. This increase was caused by adoptive transfer of lymphocytes if immune cell donors and recipient mice shared class I, but not when they shared class II histocompatibility antigens

Thinking outside the liver: induced pluripotent stem cells for hepatic applications.

Science.gov (United States)

Subba Rao, Mekala; Sasikala, Mitnala; Nageshwar Reddy, D

2013-06-14

The discovery of induced pluripotent stem cells (iPSCs) unraveled a mystery in stem cell research, after identification of four re-programming factors for generating pluripotent stem cells without the need of embryos. This breakthrough in generating iPSCs from somatic cells has overcome the ethical issues and immune rejection involved in the use of human embryonic stem cells. Hence, iPSCs form a great potential source for developing disease models, drug toxicity screening and cell-based therapies. These cells have the potential to differentiate into desired cell types, including hepatocytes, under in vitro as well as under in vivo conditions given the proper microenvironment. iPSC-derived hepatocytes could be useful as an unlimited source, which can be utilized in disease modeling, drug toxicity testing and producing autologous cell therapies that would avoid immune rejection and enable correction of gene defects prior to cell transplantation. In this review, we discuss the induction methods, role of reprogramming factors, and characterization of iPSCs, along with hepatocyte differentiation from iPSCs and potential applications. Further, we discuss the location and detection of liver stem cells and their role in liver regeneration. Although tumor formation and genetic mutations are a cause of concern, iPSCs still form a promising source for clinical applications.

Suppression of Oncolytic Adenovirus-Mediated Hepatotoxicity by Liver-Specific Inhibition of NF-κB

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Mitsuhiro Machitani

2017-12-01

Full Text Available Telomerase-specific replication-competent adenoviruses (Ads, i.e., TRADs, which possess an E1 gene expression cassette driven by the human telomerase reverse transcriptase promoter, are promising agents for cancer treatment. However, even though oncolytic Ads, including TRAD, are intratumorally administered, they are disseminated from the tumor to systemic circulation, causing concern about oncolytic Ad-mediated hepatotoxicity (due mainly to leaky expression of Ad genes in liver. We reported that inhibition of nuclear factor-κB (NF-κB leads to the suppression of replication-incompetent Ad vector-mediated hepatotoxicity via reduction of the leaky expression of Ad genes in liver. Here, to develop a TRAD with an improved safety profile, we designed a TRAD that carries a liver-specific promoter-driven dominant-negative IκBα (DNIκBα expression cassette (TRAD-DNIκBα. Compared with a conventional TRAD, TRAD-DNIκBα showed hepatocyte-specific inhibition of NF-κB signaling and significantly reduced Ad gene expression and replication in the normal human hepatocyte cell line. TRAD-induced hepatotoxicity was largely suppressed in mice following intravenous administration of TRAD-DNIκBα. However, the replication profiles and oncolytic activities of TRAD-DNIκBα were comparable with those of the conventional TRAD in human non-hepatic tumor cells. These results indicate that oncolytic Ads containing the liver-specific DNIκBα expression cassette have improved safety profiles without inhibiting oncolytic activities.

Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water.

Science.gov (United States)

Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

2015-01-01

Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury.

Death receptor and mitochondria-mediated hepatocyte apoptosis underlies liver dysfunction in rats exposed to organic pollutants from drinking water

Science.gov (United States)

Yang, Guanghong; Zhou, Zhiwei; Cen, Yanli; Gui, Xiaolin; Zeng, Qibing; Ao, Yunxia; Li, Qian; Wang, Shiran; Li, Jun; Zhang, Aihua

2015-01-01

Persistent organic pollutants in drinking water impose a substantial risk to the health of human beings, but the evidence for liver toxic effect and the underlying mechanism is scarce. This study aimed to examine the liver toxicity and elucidate the molecular mechanism of organic pollutants in drinking water in normal human liver cell line L02 cells and rats. The data showed that organic extraction from drinking water remarkably impaired rat liver function, evident from the increase in the serum level of alanine aminotransferase, aspartate aminotransferase, and cholinesterase, and decrease in the serum level of total protein and albumin. Organic extraction dose-dependently induced apoptotic cell death in rat liver and L02 cells. Administration of rats with organic extraction promoted death receptor signaling pathway through the increase in gene and protein expression level of Fas and FasL. Treatment of rats with organic extraction also induced mitochondria-mediated apoptosis via increasing the expression level of proapoptotic protein, Bax, but decreasing the expression level of antiapoptotic protein, Bcl-2, resulting in an upregulation of cytochrome c and activation of caspase cascade at both transcriptional and post-transcriptional levels. Moreover, organic extraction enhanced rat liver glutathione S-transferases activity and reactive oxygen species generation, and upregulated aryl hydrocarbon receptor and glutathione S-transferase A1 at both transcriptional and translational levels. Collectively, the results indicate that organic extraction from drinking water impairs liver function, with the involvement of death receptor and mitochondria-mediated apoptosis in rats. The results provide evidence and molecular mechanisms for organic pollutants in drinking water-induced liver dysfunction, which may help prevent and treat organic extraction-induced liver injury. PMID:26316710

Amniotic-fluid-derived mesenchymal stem cells overexpressing interleukin-1 receptor antagonist improve fulminant hepatic failure.

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Yu-Bao Zheng

Full Text Available Uncontrolled hepatic immunoactivation is regarded as the primary pathological mechanism of fulminant hepatic failure (FHF. The major acute-phase mediators associated with FHF, including IL-1β, IL-6, and TNF-α, impair the regeneration of liver cells and stem cell grafts. Amniotic-fluid-derived mesenchymal stem cells (AF-MSCs have the capacity, under specific conditions, to differentiate into hepatocytes. Interleukin-1-receptor antagonist (IL-1Ra plays an anti-inflammatory and anti-apoptotic role in acute and chronic inflammation, and has been used in many experimental and clinical applications. In the present study, we implanted IL-1Ra-expressing AF-MSCs into injured liver via the portal vein, using D-galactosamine-induced FHF in a rat model. IL-1Ra expression, hepatic injury, liver regeneration, cytokines (IL-1β, IL-6, and animal survival were assessed after cell transplantation. Our results showed that AF-MSCs over-expressing IL-1Ra prevented liver failure and reduced mortality in rats with FHF. These animals also exhibited improved liver function and increased survival rates after injection with these cells. Using green fluorescent protein as a marker, we demonstrated that the engrafted cells and their progeny were incorporated into injured livers and produced albumin. This study suggests that AF-MSCs genetically modified to over-express IL-1Ra can be implanted into the injured liver to provide a novel therapeutic approach to the treatment of FHF.

The Role of Dendritic Cells in Fibrosis Progression in Nonalcoholic Fatty Liver Disease

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Paloma Almeda-Valdes

2015-01-01

Full Text Available Nonalcoholic fatty liver disease (NAFLD is the most frequent cause of chronic liver disease. NAFLD encompasses a wide range of pathologies, from simple steatosis to steatosis with inflammation to fibrosis. The pathogenesis of NAFLD progression has not been completely elucidated, and different liver cells could be implicated. This review focuses on the current evidence of the role of liver dendritic cells (DCs in the progression from NAFLD to fibrosis. Liver DCs are a heterogeneous population of hepatic antigen-presenting cells; their main function is to induce T-cell mediated immunity by antigen processing and presentation to T cells. During the steady state liver DCs are immature and tolerogenic. However, in an environment of chronic inflammation, DCs are transformed to potent inducers of immune responses. There is evidence about the role of DC in liver fibrosis, but it is not clearly understood. Interestingly, there might be a link between lipid metabolism and DC function, suggesting that immunogenic DCs are associated with liver lipid storage, representing a possible pathophysiological mechanism in NAFLD development. A better understanding of the interaction between inflammatory pathways and the different cell types and the effect on the progression of NAFLD is of great relevance.

Dilong: Role in Peripheral Nerve Regeneration

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Yung-Ming Chang

2011-01-01

Full Text Available Dilong, also known as earthworm, has been widely used in traditional Chinese medicine (TCM for thousands of years. Schwann cell migration and proliferation are critical for the regeneration of injured nerves and Schwann cells provide an essentially supportive role for neuron regeneration. However, the molecular mechanisms of migration and proliferation induced by dilongs in Schwann cells remain unclear. Here, we discuss the molecular mechanisms that includes (i migration signaling, MAPKs (mitogen-activated protein kinases, mediated PAs and MMP2/9 pathway; (ii survival and proliferative signaling, IGF-I (insulin-like growth factor-I-mediated PI3K/Akt pathways and (iii cell cycle regulation. Dilong stimulate RSC96 cell proliferation and migration. It can induce phosphorylation of ERK1/2 and p38, but not JNK, and activate the downstream signaling expression of PAs (plasminogen activators and MMPs (matrix metalloproteinases in a time-dependent manner. In addition, Dilong stimulated ERK1/2 and p38 phosphorylation was attenuated by pretreatment with chemical inhibitors (U0126 and SB203580, and small interfering ERK1/2 and p38 RNA, resulting in migration and uPA-related signal pathway inhibition. Dilong also induces the phosphorylation of IGF-I-mediated PI3K/Akt pathway, activates protein expression of PCNA (proliferating cell nuclear antigen and cell cycle regulatory proteins (cyclin D1, cyclin E and cyclin A in a time-dependent manner. In addition, it accelerates G1-phase progression with earlier S-phase entry and significant numbers of cells entered the S-phase. The siRNA-mediated knockdown of PI3K that significantly reduces PI3K protein expression levels, resulting in Bcl2 survival factor reduction, revealing a marked blockage of G1 to S transition in proliferating cells. These results reveal the unknown RSC96 cell migration and proliferation mechanism induced by dilong, which find use as a new medicine for nerve regeneration.

All-In-One: Advanced preparation of Human Parenchymal and Non-Parenchymal Liver Cells.

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Melanie Werner

Full Text Available Liver cells are key players in innate immunity. Thus, studying primary isolated liver cells is necessary for determining their role in liver physiology and pathophysiology. In particular, the quantity and quality of isolated cells are crucial to their function. Our aim was to isolate a large quantity of high-quality human parenchymal and non-parenchymal cells from a single liver specimen.Hepatocytes, Kupffer cells, liver sinusoidal endothelial cells, and stellate cells were isolated from liver tissues by collagenase perfusion in combination with low-speed centrifugation, density gradient centrifugation, and magnetic-activated cell sorting. The purity and functionality of cultured cell populations were controlled by determining their morphology, discriminative cell marker expression, and functional activity.Cell preparation yielded the following cell counts per gram of liver tissue: 2.0 ± 0.4 × 10(7 hepatocytes, 1.8 ± 0.5 × 10(6 Kupffer cells, 4.3 ± 1.9 × 10(5 liver sinusoidal endothelial cells, and 3.2 ± 0.5 × 10(5 stellate cells. Hepatocytes were identified by albumin (95.5 ± 1.7% and exhibited time-dependent activity of cytochrome P450 enzymes. Kupffer cells expressed CD68 (94.5 ± 1.2% and exhibited phagocytic activity, as determined with 1 μm latex beads. Endothelial cells were CD146(+ (97.8 ± 1.1% and exhibited efficient uptake of acetylated low-density lipoprotein. Hepatic stellate cells were identified by the expression of α-smooth muscle actin (97.1 ± 1.5%. These cells further exhibited retinol (vitamin A-mediated autofluorescence.Our isolation procedure for primary parenchymal and non-parenchymal liver cells resulted in cell populations of high purity and quality, with retained physiological functionality in vitro. Thus, this system may provide a valuable tool for determining liver function and disease.

Rat Liver Enzyme Release Depends on Blood Flow-Bearing Physical Forces Acting in Endothelium Glycocalyx rather than on Liver Damage

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Julieta A. Díaz-Juárez

2017-01-01

Full Text Available We have found selective elevation of serum enzyme activities in rats subjected to partial hepatectomy (PH, apparently controlled by hemodynamic flow-bearing physical forces. Here, we assess the involvement of stretch-sensitive calcium channels and calcium mobilization in isolated livers, after chemical modifications of the endothelial glycocalyx and changing perfusion directionality. Inhibiting in vivo protein synthesis, we found that liver enzyme release is influenced by de novo synthesis of endothelial glycocalyx components, and released enzymes are confined into a liver “pool.” Moreover, liver enzyme release depended on extracellular calcium entry possibly mediated by stretch-sensitive calcium channels, and this endothelial-mediated mechanotransduction in liver enzyme release was also evidenced by modifying the glycocalyx carbohydrate components, directionality of perfusing flow rate, and the participation of nitric oxide (NO and malondialdehyde (MDA, leading to modifications in the intracellular distribution of these enzymes mainly as nuclear enrichment of “mitochondrial” enzymes. In conclusion, the flow-induced shear stress may provide fine-tuned control of released hepatic enzymes through mediation by the endothelium glycocalyx, which provides evidence of a biological role of the enzyme release rather to be merely a biomarker for evaluating hepatotoxicity and liver damage, actually positively influencing progression of liver regeneration in mammals.

Myocardial regeneration potential of adipose tissue-derived stem cells

Energy Technology Data Exchange (ETDEWEB)

Bai, Xiaowen, E-mail: baixw01@yahoo.com [Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe, Houston, TX 77030 (United States); Alt, Eckhard, E-mail: ealt@mdanderson.org [Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe, Houston, TX 77030 (United States)

2010-10-22

Research highlights: {yields} Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. {yields} For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. {yields} This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derived stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the

Myocardial regeneration potential of adipose tissue-derived stem cells

International Nuclear Information System (INIS)

Bai, Xiaowen; Alt, Eckhard

2010-01-01

Research highlights: → Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. → For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. → This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derived stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the underlying

Live-cell imaging: new avenues to investigate retinal regeneration

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Manuela Lahne

2017-01-01

Full Text Available Sensing and responding to our environment requires functional neurons that act in concert. Neuronal cell loss resulting from degenerative diseases cannot be replaced in humans, causing a functional impairment to integrate and/or respond to sensory cues. In contrast, zebrafish (Danio rerio possess an endogenous capacity to regenerate lost neurons. Here, we will focus on the processes that lead to neuronal regeneration in the zebrafish retina. Dying retinal neurons release a damage signal, tumor necrosis factor α, which induces the resident radial glia, the Müller glia, to reprogram and re-enter the cell cycle. The Müller glia divide asymmetrically to produce a Müller glia that exits the cell cycle and a neuronal progenitor cell. The arising neuronal progenitor cells undergo several rounds of cell divisions before they migrate to the site of damage to differentiate into the neuronal cell types that were lost. Molecular and immunohistochemical studies have predominantly provided insight into the mechanisms that regulate retinal regeneration. However, many processes during retinal regeneration are dynamic and require live-cell imaging to fully discern the underlying mechanisms. Recently, a multiphoton imaging approach of adult zebrafish retinal cultures was developed. We will discuss the use of live-cell imaging, the currently available tools and those that need to be developed to advance our knowledge on major open questions in the field of retinal regeneration.

Magnetic field exposure stiffens regenerating plant protoplast cell walls.

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Haneda, Toshihiko; Fujimura, Yuu; Iino, Masaaki

2006-02-01

Single suspension-cultured plant cells (Catharanthus roseus) and their protoplasts were anchored to a glass plate and exposed to a magnetic field of 302 +/- 8 mT for several hours. Compression forces required to produce constant cell deformation were measured parallel to the magnetic field by means of a cantilever-type force sensor. Exposure of intact cells to the magnetic field did not result in any changes within experimental error, while exposure of regenerating protoplasts significantly increased the measured forces and stiffened regenerating protoplasts. The diameters of intact cells or regenerating protoplasts were not changed after exposure to the magnetic field. Measured forces for regenerating protoplasts with and without exposure to the magnetic field increased linearly with incubation time, with these forces being divided into components based on the elasticity of synthesized cell walls and cytoplasm. Cell wall synthesis was also measured using a cell wall-specific fluorescent dye, and no changes were noted after exposure to the magnetic field. Analysis suggested that exposure to the magnetic field roughly tripled the Young's modulus of the newly synthesized cell wall without any lag.

Polyploidization of liver cells.

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Celton-Morizur, Séverine; Desdouets, Chantal

2010-01-01

Eukaryotic organisms usually contain a diploid complement of chromosomes. However, there are a number of exceptions. Organisms containing an increase in DNA content by whole number multiples of the entire set of chromosomes are defined as polyploid. Cells that contain more than two sets of chromosomes were first observed in plants about a century ago and it is now recognized that polyploidy cells form in many eukaryotes under a wide variety of circumstance. Although it is less common in mammals, some tissues, including the liver, show a high percentage of polyploid cells. Thus, during postnatal growth, the liver parenchyma undergoes dramatic changes characterized by gradual polyploidization during which hepatocytes of several ploidy classes emerge as a result of modified cell-division cycles. This process generates the successive appearance of tetraploid and octoploid cell classes with one or two nuclei (mononucleated or binucleated). Liver cells polyploidy is generally considered to indicate terminal differentiation and senescence and to lead both to the progressive loss of cell pluripotency and a markedly decreased replication capacity. In adults, liver polyploidization is differentially regulated upon loss of liver mass and liver damage. Interestingly, partial hepatectomy induces marked cell proliferation followed by an increase in liver ploidy. In contrast, during hepatocarcinoma (HCC), growth shifts to a nonpolyploidizing pattern and expansion of the diploid hepatocytes population is observed in neoplastic nodules. Here we review the current state of understanding about how polyploidization is regulated during normal and pathological liver growth and detail by which mechanisms hepatocytes become polyploid.

Circulating histones are major mediators of systemic inflammation and cellular injury in patients with acute liver failure.

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Wen, Zongmei; Lei, Zhen; Yao, Lu; Jiang, Ping; Gu, Tao; Ren, Feng; Liu, Yan; Gou, Chunyan; Li, Xiuhui; Wen, Tao

2016-09-29

Acute liver failure (ALF) is a life-threatening systemic disorder. Here we investigated the impact of circulating histones, recently identified inflammatory mediators, on systemic inflammation and liver injury in murine models and patients with ALF. We analyzed histone levels in blood samples from 62 patients with ALF, 60 patients with chronic liver disease, and 30 healthy volunteers. We incubated patients' sera with human L02 hepatocytes and monocytic U937 cells to assess cellular damage and cytokine production. d-galactosamine plus lipopolysaccharide (GalN/LPS), concanavalin A (ConA), and acetaminophen (APAP) were given to C57BL/6N mice to induce liver injury, respectively, and the pathogenic role of circulating histones was studied. Besides, the protective effect of nonanticoagulant heparin, which can bind histones, was evaluated with in vivo and ex vivo investigations. We observed that circulating histones were significantly increased in patients with ALF, and correlated with disease severity and mortality. Significant systemic inflammation was also pronounced in ALF patients, which were associated with histone levels. ALF patients' sera induced significant L02 cell death and stimulated U937 cells to produce cytokines, which were abrogated by nonanticoagulant heparin. Furthermore, circulating histones were all released remarkably in GalN/LPS, ConA, and APAP-treated mice, and associated with high levels of inflammatory cytokines. Heparin reduced systemic inflammation and liver damage in mice, suggesting that it could interfere with histone-associated liver injury. Collectively, these findings demonstrate that circulating histones are critical mediators of systemic inflammation and cellular damage in ALF, which may be potentially translatable for clinical use.

Mammalian Cochlear Hair Cell Regeneration and Ribbon Synapse Reformation

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Xiaoling Lu

2016-01-01

Full Text Available Hair cells (HCs are the sensory preceptor cells in the inner ear, which play an important role in hearing and balance. The HCs of organ of Corti are susceptible to noise, ototoxic drugs, and infections, thus resulting in permanent hearing loss. Recent approaches of HCs regeneration provide new directions for finding the treatment of sensor neural deafness. To have normal hearing function, the regenerated HCs must be reinnervated by nerve fibers and reform ribbon synapse with the dendrite of spiral ganglion neuron through nerve regeneration. In this review, we discuss the research progress in HC regeneration, the synaptic plasticity, and the reinnervation of new regenerated HCs in mammalian inner ear.

Phosphatase and tensin homolog-β-catenin signaling modulates regulatory T cells and inflammatory responses in mouse liver ischemia/reperfusion injury.

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Zhu, Qiang; Li, Changyong; Wang, Kunpeng; Yue, Shi; Jiang, Longfeng; Ke, Michael; Busuttil, Ronald W; Kupiec-Weglinski, Jerzy W; Zhang, Feng; Lu, Ling; Ke, Bibo

2017-06-01

The phosphatase and tensin homolog (PTEN) deleted on chromosome 10 plays an important role in regulating T cell activation during inflammatory response. Activation of β-catenin is crucial for maintaining immune homeostasis. This study investigates the functional roles and molecular mechanisms by which PTEN-β-catenin signaling promotes regulatory T cell (Treg) induction in a mouse model of liver ischemia/reperfusion injury (IRI). We found that mice with myeloid-specific phosphatase and tensin homolog knockout (PTEN M-KO ) exhibited reduced liver damage as evidenced by decreased levels of serum alanine aminotransferase, intrahepatic macrophage trafficking, and proinflammatory mediators compared with the PTEN-proficient (floxed phosphatase and tensin homolog [PTEN FL/FL ]) controls. Disruption of myeloid PTEN-activated b-catenin promoted peroxisome proliferator-activated receptor gamma (PPARγ)-mediated Jagged-1/Notch signaling and induced forkhead box P3 (FOXP3)1 Tregs while inhibiting T helper 17 cells. However, blocking of Notch signaling by inhibiting γ-secretase reversed myeloid PTEN deficiency-mediated protection in ischemia/reperfusion-triggered liver inflammation with reduced FOXP3 + and increased retinoid A receptor-related orphan receptor gamma t-mediated interleukin 17A expression in ischemic livers. Moreover, knockdown of β-catenin or PPARγ in PTEN-deficient macrophages inhibited Jagged-1/Notch activation and reduced FOXP3 + Treg induction, leading to increased proinflammatory mediators in macrophage/T cell cocultures. In conclusion, our findings demonstrate that PTEN-β-catenin signaling is a novel regulator involved in modulating Treg development and provides a potential therapeutic target in liver IRI. Liver Transplantation 23 813-825 2017 AASLD. © 2017 by the American Association for the Study of Liver Diseases.

[Effects of three Wenyang Jianpi Tang on cell proliferation and apoptosis of nonalcoholic fatty liver cells].

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Yang, Jia-Yao; Tao, Dong-Qing; Liu, Song; Zhang, Shu; Ma, Wei; Shi, Zhao-Hong

2017-04-01

proliferation, and inhibit the cellular apoptosis of nonalcoholic fatty liver cells. And Fuzi Lizhong Tang showed the best effect. The pharmacodynamic mechanism may be related to the expressions of key factors in pathways related with proliferation and apoptosis mediated by the three decoctions. Copyright© by the Chinese Pharmaceutical Association.

Natural indoles, indole-3-carbinol (I3C and 3,3'-diindolylmethane (DIM, attenuate staphylococcal enterotoxin B-mediated liver injury by downregulating miR-31 expression and promoting caspase-2-mediated apoptosis.

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Philip B Busbee

Full Text Available Staphylococcal enterotoxin B (SEB is a potent superantigen capable of inducing inflammation characterized by robust immune cell activation and proinflammatory cytokine release. Exposure to SEB can result in food poisoning as well as fatal conditions such as toxic shock syndrome. In the current study, we investigated the effect of natural indoles including indole-3-carbinol (I3C and 3,3'-diindolylmethane (DIM on SEB-mediated liver injury. Injection of SEB into D-galactosamine-sensitized female C57BL/6 mice resulted in liver injury as indicated by an increase in enzyme aspartate transaminase (AST levels, induction of inflammatory cytokines, and massive infiltration of immune cells into the liver. Administration of I3C and DIM (40 mg/kg, by intraperitonal injection, attenuated SEB-induced acute liver injury, as evidenced by decrease in AST levels, inflammatory cytokines and cellular infiltration in the liver. I3C and DIM triggered apoptosis in SEB-activated T cells primarily through activation of the intrinsic mitochondrial pathway. In addition, inhibitor studies involving caspases revealed that I3C and DIM-mediated apoptosis in these activated cells was dependent on caspase-2 but independent of caspase-8, 9 and 3. In addition, I3C and DIM caused a decrease in Bcl-2 expression. Both compounds also down-regulated miR-31, which directly targets caspase-2 and influences apoptosis in SEB-activated cells. Our data demonstrate for the first time that indoles can effectively suppress acute hepatic inflammation caused by SEB and that this may be mediated by decreased expression of miR-31 and consequent caspase-2-dependent apoptosis in T cells.

Dental mesenchymal stem cells encapsulated in alginate hydrogel co-delivery microencapsulation system for cartilage regeneration

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Moshaverinia, Alireza; Xu, Xingtian; Chen, Chider; Akiyama, Kentaro; Snead, Malcolm L; Shi, Songtao

2013-01-01

Dental-derived MSCs are promising candidates for cartilage regeneration, with high chondrogenic differentiation capacity. This property contributes to making dental MSCs an advantageous therapeutic option compared to current treatment modalities. The MSC delivery vehicle is the principal determinant for the success of MSC-mediated cartilage regeneration therapies. The objectives of this study were to: (1) develop a novel co-delivery system based on TGF-β1 loaded RGD-coupled alginate microspheres encapsulating Periodontal Ligament Stem Cells (PDLSCs) or Gingival Mesenchymal Stem Cells (GMSCs); and (2) investigate dental MSC viability and chondrogenic differentiation in alginate microspheres. The results revealed the sustained release of TGF-β1 from the alginate microspheres. After 4 weeks of chondrogenic differentiation in vitro, PDLSCs, GMSCs as well as human bone marrow mesenchymal stem cells (hBMMSC) (as positive control) revealed chondrogenic gene expression markers (Col II and Sox-9) via qPCR, as well as matrix positively stained by toluidine blue and safranin-O. In animal studies, ectopic cartilage tissue regeneration was observed inside and around the transplanted microspheres, confirmed by histochemical and immunofluorescent staining. Interestingly, PDLSCs showed more chondrogenesis than GMSCs and hBMMSCs (Palginate microencapsulating dental MSCs make a promising candidate for cartilage regeneration. Our results highlight the vital role played by the microenvironment, as well as value of presenting inductive signals for viability and differentiation of MSCs. PMID:23891740

Induction and maintenance of protective CD8+ T cells against malaria liver stages: implications for vaccine development

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Sze-Wah Tse

2011-08-01

Full Text Available CD8+ T cells against malaria liver stages represent a major protective immune mechanism against infection. Following induction in the peripheral lymph nodes by dendritic cells (DCs, these CD8+ T cells migrate to the liver and eliminate parasite infected hepatocytes. The processing and presentation of sporozoite antigen requires TAP mediated transport of major histocompatibility complex class I epitopes to the endoplasmic reticulum. Importantly, in DCs this process is also dependent on endosome-mediated cross presentation while this mechanism is not required for epitope presentation on hepatocytes. Protective CD8+ T cell responses are strongly dependent on the presence of CD4+ T cells and the capacity of sporozoite antigen to persist for a prolonged period of time. While human trials with subunit vaccines capable of inducing antibodies and CD4+ T cell responses have yielded encouraging results, an effective anti-malaria vaccine will likely require vaccine constructs designed to induce protective CD8+ T cells against malaria liver stages.

Perspectives on stem cell therapy for cardiac regeneration. Advances and challenges.

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Choi, Sung Hyun; Jung, Seok Yun; Kwon, Sang-Mo; Baek, Sang Hong

2012-01-01

Ischemic heart disease (IHD) accelerates cardiomyocyte loss, but the developing stem cell research could be useful for regenerating a variety of tissue cells, including cardiomyocytes. Diverse sources of stem cells for IHD have been reported, including embryonic stem cells, induced pluripotent stem cells, skeletal myoblasts, bone marrow-derived stem cells, mesenchymal stem cells, and cardiac stem cells. However, stem cells have unique advantages and disadvantages for cardiac tissue regeneration, which are important considerations in determining the specific cells for improving cell survival and long-term engraftment after transplantation. Additionally, the dosage and administration method of stem cells need to be standardized to increase stability and efficacy for clinical applications. Accordingly, this review presents a summary of the stem cell therapies that have been studied for cardiac regeneration thus far, and discusses the direction of future cardiac regeneration research for stem cells.

Transplant of Hepatocytes, Undifferentiated Mesenchymal Stem Cells, and In Vitro Hepatocyte-Differentiated Mesenchymal Stem Cells in a Chronic Liver Failure Experimental Model: A Comparative Study.

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El Baz, Hanan; Demerdash, Zeinab; Kamel, Manal; Atta, Shimaa; Salah, Faten; Hassan, Salwa; Hammam, Olfat; Khalil, Heba; Meshaal, Safa; Raafat, Inas

2018-02-01

Liver transplant is the cornerstone line of treatment for chronic liver diseases; however, the long list of complications and obstacles stand against this operation. Searching for new modalities for treatment of chronic liver illness is a must. In the present research, we aimed to compare the effects of transplant of undifferentiated human mesenchymal stem cells, in vitro differentiated mesenchymal stem cells, and adult hepatocytes in an experimental model of chronic liver failure. Undifferentiated human cord blood mesenchymal stem cells were isolated, pro-pagated, and characterized by morphology, gene expression analysis, and flow cytometry of surface markers and in vitro differentiated into hepatocyte-like cells. Rat hepatocytes were isolated by double perfusion technique. An animal model of chronic liver failure was developed, and undifferentiated human cord blood mesenchymal stem cells, in vitro hepato-genically differentiated mesenchymal stem cells, or freshly isolated rat hepatocytes were transplanted into a CCL4 cirrhotic experimental model. Animals were killed 3 months after transplant, and liver functions and histopathology were assessed. Compared with the cirrhotic control group, the 3 cell-treated groups showed improved alanine aminotransferase, aspartate aminotransferase, albumin, and bilirubin levels, with best results shown in the hepatocyte-treated group. Histopathologic examination of the treated groups showed improved fibrosis, with best results obtained in the undifferentiated mesenchymal stem cell-treated group. Both adult hepatocytes and cord blood mesenchymal stem cells proved to be promising candidates for cell-based therapy in liver regeneration on an experimental level. Improved liver function was evident in the hepatocyte-treated group, and fibrosis control was more evident in the undifferentiated mesenchymal stem cell-treated group.

Regenerating reptile retinas: a comparative approach to restoring retinal ganglion cell function.

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Williams, D L

2017-02-01

Transection or damage to the mammalian optic nerve generally results in loss of retinal ganglion cells by apoptosis. This cell death is seen less in fish or amphibians where retinal ganglion cell survival and axon regeneration leads to recovery of sight. Reptiles lie somewhere in the middle of this spectrum of nerve regeneration, and different species have been reported to have a significant variation in their retinal ganglion cell regenerative capacity. The ornate dragon lizard Ctenophoris ornatus exhibits a profound capacity for regeneration, whereas the Tenerife wall lizard Gallotia galloti has a more variable response to optic nerve damage. Some individuals regain visual activity such as the pupillomotor responses, whereas in others axons fail to regenerate sufficiently. Even in Ctenophoris, although the retinal ganglion cell axons regenerate adequately enough to synapse in the tectum, they do not make long-term topographic connections allowing recovery of complex visually motivated behaviour. The question then centres on where these intraspecies differences originate. Is it variation in the innate ability of retinal ganglion cells from different species to regenerate with functional validity? Or is it variances between different species in the substrate within which the nerves regenerate, the extracellular environment of the damaged nerve or the supporting cells surrounding the regenerating axons? Investigations of retinal ganglion cell regeneration between different species of lower vertebrates in vivo may shed light on these questions. Or perhaps more interesting are in vitro studies comparing axon regeneration of retinal ganglion cells from various species placed on differing substrates.

[Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

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Liang, Hang; Deng, Xiangyu; Shao, Zengwu

2017-10-01

To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

Dentin and dental pulp regeneration by the patient's endogenous cells.

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Kim, Sahng G; Zheng, Ying; Zhou, Jian; Chen, Mo; Embree, Mildred C; Song, Karen; Jiang, Nan; Mao, Jeremy J

2013-03-01

The goal of regenerative endodontics is to restore the functions of the dental pulp-dentin complex. Two approaches are being applied toward dental pulp-dentin regeneration: cell transplantation and cell homing. The majority of previous approaches are based on cell transplantation by delivering ex vivo cultivated cells toward dental pulp or dentin regeneration. Many hurdles limit the clinical translation of cell transplantation such as the difficulty of acquiring and isolating viable cells, uncertainty of what cells or what fractions of cells to use, excessive cost of cell manipulation and transportation, and the risk of immune rejection, pathogen transmission, and tumorigenesis in associated with ex vivo cell manipulation. In contrast, cell homing relies on induced chemotaxis of endogenous cells and therefore circumvents many of the difficulties that are associated with cell transplantation. An array of proteins, peptides, and chemical compounds that are yet to be identified may orchestrate endogenous cells to regenerate dental pulp-dentin complex. Both cell transplantation and cell homing are scientifically valid approaches; however, cell homing offers a number of advantages that are compatible with the development of clinical therapies for dental pulp-dentin regeneration.

Adipose-Derived Stem Cells Promote Peripheral Nerve Regeneration In Vivo without Differentiation into Schwann-Like Lineage.

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Sowa, Yoshihiro; Kishida, Tsunao; Imura, Tetsuya; Numajiri, Toshiaki; Nishino, Kenichi; Tabata, Yasuhiko; Mazda, Osam

2016-02-01

During recent decades, multipotent stem cells were found to reside in the adipose tissue, and these adipose-derived stem cells were shown to play beneficial roles, like those of Schwann cells, in peripheral nerve regeneration. However, it has not been well established whether adipose-derived stem cells offer beneficial effects to peripheral nerve injuries in vivo as Schwann cells do. Furthermore, the in situ survival and differentiation of adipose-derived stem cells after transplantation at the injured peripheral nerve tissue remain to be fully elucidated. Adipose-derived stem cells and Schwann cells were transplanted with gelatin hydrogel tubes at the artificially blunted sciatic nerve lesion in mice. Neuroregenerative abilities of them were comparably estimated. Cre-loxP-mediated fate tracking was performed to visualize survival in vivo of transplanted adipose-derived stem cells and to investigate whether they differentiated into Schwann linage cells at the peripheral nerve injury site. The transplantation of adipose-derived stem cells promoted regeneration of axons, formation of myelin, and restoration of denervation muscle atrophy to levels comparable to those achieved by Schwann cell transplantation. The adipose-derived stem cells survived for at least 4 weeks after transplantation without differentiating into Schwann cells. Transplanted adipose-derived stem cells did not differentiate into Schwann cells but promoted peripheral nerve regeneration at the injured site. The neuroregenerative ability was comparable to that of Schwann cells. Adipose-derived stem cells at an undifferentiated stage may be used as an alternative cell source for autologous cell therapy for patients with peripheral nerve injury.

Role of adenosine signalling and metabolism in β-cell regeneration

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Andersson, Olov, E-mail: olov.andersson@ki.se

2014-02-01

Glucose homeostasis, which is controlled by the endocrine cells of the pancreas, is disrupted in both type I and type II diabetes. Deficiency in the number of insulin-producing β cells – a primary cause of type I diabetes and a secondary contributor of type II diabetes – leads to hyperglycemia and hence an increase in the need for insulin. Although diabetes can be controlled with insulin injections, a curative approach is needed. A potential approach to curing diabetes involves regenerating the β-cell mass, e.g. by increasing β-cell proliferation, survival, neogenesis or transdifferentiation. The nucleoside adenosine and its cognate nucleotide ATP have long been known to affect insulin secretion, but have more recently been shown to increase β-cell proliferation during homeostatic control and regeneration of the β-cell mass. Adenosine is also known to have anti-inflammatory properties, and agonism of adenosine receptors can promote the survival of β-cells in an inflammatory microenvironment. In this review, both intracellular and extracellular mechanisms of adenosine and ATP are discussed in terms of their established and putative effects on β-cell regeneration. - Highlights: • A potential way to cure diabetes is to regenerate the β-cell mass by promoting cell survival, proliferation or neogenesis. • Adenosine may promote β-cell regeneration through several cellular mechanisms. • Adenosine and its cognate nucleotide ATP can each promote β-cell proliferation. • Do adenosine and ATP interact in promoting β-cell proliferation?.

Role of adenosine signalling and metabolism in β-cell regeneration

International Nuclear Information System (INIS)

Andersson, Olov

2014-01-01

Glucose homeostasis, which is controlled by the endocrine cells of the pancreas, is disrupted in both type I and type II diabetes. Deficiency in the number of insulin-producing β cells – a primary cause of type I diabetes and a secondary contributor of type II diabetes – leads to hyperglycemia and hence an increase in the need for insulin. Although diabetes can be controlled with insulin injections, a curative approach is needed. A potential approach to curing diabetes involves regenerating the β-cell mass, e.g. by increasing β-cell proliferation, survival, neogenesis or transdifferentiation. The nucleoside adenosine and its cognate nucleotide ATP have long been known to affect insulin secretion, but have more recently been shown to increase β-cell proliferation during homeostatic control and regeneration of the β-cell mass. Adenosine is also known to have anti-inflammatory properties, and agonism of adenosine receptors can promote the survival of β-cells in an inflammatory microenvironment. In this review, both intracellular and extracellular mechanisms of adenosine and ATP are discussed in terms of their established and putative effects on β-cell regeneration. - Highlights: • A potential way to cure diabetes is to regenerate the β-cell mass by promoting cell survival, proliferation or neogenesis. • Adenosine may promote β-cell regeneration through several cellular mechanisms. • Adenosine and its cognate nucleotide ATP can each promote β-cell proliferation. • Do adenosine and ATP interact in promoting β-cell proliferation?

Liver-Enriched Gene 1, a Glycosylated Secretory Protein, Binds to FGFR and Mediates an Anti-stress Pathway to Protect Liver Development in Zebrafish.

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Minjie Hu

2016-02-01

Full Text Available Unlike mammals and birds, teleost fish undergo external embryogenesis, and therefore their embryos are constantly challenged by stresses from their living environment. These stresses, when becoming too harsh, will cause arrest of cell proliferation, abnormal cell death or senescence. Such organisms have to evolve a sophisticated anti-stress mechanism to protect the process of embryogenesis/organogenesis. However, very few signaling molecule(s mediating such activity have been identified. liver-enriched gene 1 (leg1 is an uncharacterized gene that encodes a novel secretory protein containing a single domain DUF781 (domain of unknown function 781 that is well conserved in vertebrates. In the zebrafish genome, there are two copies of leg1, namely leg1a and leg1b. leg1a and leg1b are closely linked on chromosome 20 and share high homology, but are differentially expressed. In this report, we generated two leg1a mutant alleles using the TALEN technique, then characterized liver development in the mutants. We show that a leg1a mutant exhibits a stress-dependent small liver phenotype that can be prevented by chemicals blocking the production of reactive oxygen species. Further studies reveal that Leg1a binds to FGFR3 and mediates a novel anti-stress pathway to protect liver development through enhancing Erk activity. More importantly, we show that the binding of Leg1a to FGFR relies on the glycosylation at the 70th asparagine (Asn(70 or N(70, and mutating the Asn(70 to Ala(70 compromised Leg1's function in liver development. Therefore, Leg1 plays a unique role in protecting liver development under different stress conditions by serving as a secreted signaling molecule/modulator.

Liver Immunology

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Bogdanos, Dimitrios P.; Gao, Bin; Gershwin, M. Eric

2014-01-01

The liver is the largest organ in the body and is generally regarded by non-immunologists as not having lymphoid function. However, such is far from accurate. This review highlights the importance of the liver as a lymphoid organ. Firstly, we discuss experimental data surrounding the role of liver as a lymphoid organ. The liver facilitates a tolerance rather than immunoreactivity, which protects the host from antigenic overload of dietary components and drugs derived from the gut and is also instrumental to fetal immune tolerance. Loss of liver tolerance leads to autoaggressive phenomena which if are not controlled by regulatory lymphoid populations may lead to the induction of autoimmune liver diseases. Liver-related lymphoid subpopulations also act as critical antigen-presenting cells. The study of the immunological properties of liver and delineation of the microenvironment of the intrahepatic milieu in normal and diseased livers provides a platform to understand the hierarchy of a series of detrimental events which lead to immune-mediated destruction of the liver and the rejection of liver allografts. The majority of emphasis within this review will be on the normal mononuclear cell composition of the liver. However, within this context, we will discus select, but not all, immune mediated liver disease and attempt to place these data in the context of human autoimmunity. PMID:23720323

The Urodele Limb Regeneration Blastema: The Cell Potential

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Kenyon S. Tweedell

2010-01-01

Full Text Available The developmental potential of the limb regeneration blastema, a mass of mesenchymal cells of mixed origins, was once considered as being pluripotent, capable of forming all cell types. Now evidence asserts that the blastema is a heterogeneous mixture of progenitor cells derived from tissues of the amputation site, with limited developmental potential, plus various stem cells with multipotent abilities. Many specialized cells, bone, cartilage, muscle, and Schwann cells, at the injury site undergo dedifferentiation to a progenitor state and maintain their cell lineage as they redifferentiate in the regenerate. Muscle satellite reserve stem cells that are active in repair of injured muscle may also dedifferentiate and contribute new muscle cells to the limb blastema. Other cells from the dermis act as multipotent stem cells that replenish dermal fibroblasts and differentiate into cartilage. The blastema primordium is a self-organized, equipotential system, but at the cellular level can compensate for specific cell loss. It is able to induce dedifferentiation of introduced exogenous cells and such cells may be transformed into new cell types. Indigenous cells of the blastema associated with amputated tissues may also transform or possibly transdifferentiate into new cell types. The blastema is a microenvironment that enables dedifferentiation, redifferentiation, transdifferentiation, and stem cell activation, leading to progenitor cells of the limb regenerate.

Dental mesenchymal stem cells encapsulated in an alginate hydrogel co-delivery microencapsulation system for cartilage regeneration.

Science.gov (United States)

Moshaverinia, Alireza; Xu, Xingtian; Chen, Chider; Akiyama, Kentaro; Snead, Malcolm L; Shi, Songtao

2013-12-01

Dental-derived mesenchymal stem cells (MSCs) are promising candidates for cartilage regeneration, with a high capacity for chondrogenic differentiation. This property helps make dental MSCs an advantageous therapeutic option compared to current treatment modalities. The MSC delivery vehicle is the principal determinant for the success of MSC-mediated cartilage regeneration therapies. The objectives of this study were to: (1) develop a novel co-delivery system based on TGF-β1 loaded RGD-coupled alginate microspheres encapsulating periodontal ligament stem cells (PDLSCs) or gingival mesenchymal stem cells (GMSCs); and (2) investigate dental MSC viability and chondrogenic differentiation in alginate microspheres. The results revealed the sustained release of TGF-β1 from the alginate microspheres. After 4 weeks of chondrogenic differentiation in vitro, PDLSCs and GMSCs as well as human bone marrow mesenchymal stem cells (hBMMSCs) (as positive control) revealed chondrogenic gene expression markers (Col II and Sox-9) via qPCR, as well as matrix positively stained by Toluidine Blue and Safranin-O. In animal studies, ectopic cartilage tissue regeneration was observed inside and around the transplanted microspheres, confirmed by histochemical and immunofluorescent staining. Interestingly, PDLSCs showed more chondrogenesis than GMSCs and hBMMSCs (palginate microencapsulating dental MSCs make a promising candidate for cartilage regeneration. Our results highlight the vital role played by the microenvironment, as well as value of presenting inductive signals for viability and differentiation of MSCs. Copyright © 2013 Acta Materialia Inc. All rights reserved.

Development and regeneration of vestibular hair cells in mammals.

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Burns, Joseph C; Stone, Jennifer S

2017-05-01

Vestibular sensation is essential for gaze stabilization, balance, and perception of gravity. The vestibular receptors in mammals, Type I and Type II hair cells, are located in five small organs in the inner ear. Damage to hair cells and their innervating neurons can cause crippling symptoms such as vertigo, visual field oscillation, and imbalance. In adult rodents, some Type II hair cells are regenerated and become re-innervated after damage, presenting opportunities for restoring vestibular function after hair cell damage. This article reviews features of vestibular sensory cells in mammals, including their basic properties, how they develop, and how they are replaced after damage. We discuss molecules that control vestibular hair cell regeneration and highlight areas in which our understanding of development and regeneration needs to be deepened. Copyright © 2016 Elsevier Ltd. All rights reserved.

TRAIL enhances paracetamol-induced liver sinusoidal endothelial cell death in a Bim- and Bid-dependent manner

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Badmann, A; Langsch, S; Keogh, A; Brunner, T; Kaufmann, T; Corazza, N

2012-01-01

Paracetamol (acetaminophen, APAP) is a universally used analgesic and antipyretic agent. Considered safe at therapeutic doses, overdoses cause acute liver damage characterized by centrilobular hepatic necrosis. One of the major clinical problems of paracetamol-induced liver disease is the development of hemorrhagic alterations. Although hepatocytes represent the main target of the cytotoxic effect of paracetamol overdose, perturbations within the endothelium involving morphological changes of liver sinusoidal endothelial cells (LSECs) have also been described in paracetamol-induced liver disease. Recently, we have shown that paracetamol-induced liver damage is synergistically enhanced by the TRAIL signaling pathway. As LSECs are constantly exposed to activated immune cells expressing death ligands, including TRAIL, we investigated the effect of TRAIL on paracetamol-induced LSEC death. We here demonstrate for the first time that TRAIL strongly enhances paracetamol-mediated LSEC death with typical features of apoptosis. Inhibition of caspases using specific inhibitors resulted in a strong reduction of cell death. TRAIL appears to enhance paracetamol-induced LSEC death via the activation of the pro-apoptotic BH3-only proteins Bid and Bim, which initiate the mitochondrial apoptotic pathway. Taken together this study shows that the liver endothelial layer, mainly LSECs, represent a direct target of the cytotoxic effect of paracetamol and that activation of TRAIL receptor synergistically enhances paracetamol-induced LSEC death via the mitochondrial apoptotic pathway. TRAIL-mediated acceleration of paracetamol-induced cell death may thus contribute to the pathogenesis of paracetamol-induced liver damage. PMID:23254290

Eye Absence Does Not Regulate Planarian Stem Cells during Eye Regeneration.

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LoCascio, Samuel A; Lapan, Sylvain W; Reddien, Peter W

2017-02-27

Dividing cells called neoblasts contain pluripotent stem cells and drive planarian flatworm regeneration from diverse injuries. A long-standing question is whether neoblasts directly sense and respond to the identity of missing tissues during regeneration. We used the eye to investigate this question. Surprisingly, eye removal was neither sufficient nor necessary for neoblasts to increase eye progenitor production. Neoblasts normally increase eye progenitor production following decapitation, facilitating regeneration. Eye removal alone, however, did not induce this response. Eye regeneration following eye-specific resection resulted from homeostatic rates of eye progenitor production and less cell death in the regenerating eye. Conversely, large head injuries that left eyes intact increased eye progenitor production. Large injuries also non-specifically increased progenitor production for multiple uninjured tissues. We propose a model for eye regeneration in which eye tissue production by planarian stem cells is not directly regulated by the absence of the eye itself. Copyright © 2017 Elsevier Inc. All rights reserved.

Adenosine signaling promotes regeneration of pancreatic β-cells in vivo

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Andersson, Olov; Adams, Bruce A.; Yoo, Daniel; Ellis, Gregory C.; Gut, Philipp; Anderson, Ryan M.; German, Michael S.; Stainier, Didier Y. R.

2012-01-01

Diabetes can be controlled with insulin injections, but a curative approach that restores the number of insulin-producing β-cells is still needed. Using a zebrafish model of diabetes, we screened ~7000 small molecules to identify enhancers of β-cell regeneration. The compounds we identified converge on the adenosine signaling pathway and include exogenous agonists and compounds that inhibit degradation of endogenously produced adenosine. The most potent enhancer of β-cell regeneration was the adenosine agonist 5′-N-Ethylcarboxamidoadenosine (NECA), which acting through the adenosine receptor A2aa increased β-cell proliferation and accelerated restoration of normoglycemia in zebrafish. Despite markedly stimulating β-cell proliferation during regeneration, NECA had only a modest effect during development. The proliferative and glucose-lowering effect of NECA was confirmed in diabetic mice, suggesting an evolutionarily conserved role for adenosine in β-cell regeneration. With this whole-organism screen, we identified components of the adenosine pathway that could be therapeutically targeted for the treatment of diabetes. PMID:22608007

Human airway xenograft models of epithelial cell regeneration

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Puchelle Edith

2000-10-01

Full Text Available Abstract Regeneration and restoration of the airway epithelium after mechanical, viral or bacterial injury have a determinant role in the evolution of numerous respiratory diseases such as chronic bronchitis, asthma and cystic fibrosis. The study in vivo of epithelial regeneration in animal models has shown that airway epithelial cells are able to dedifferentiate, spread, migrate over the denuded basement membrane and progressively redifferentiate to restore a functional respiratory epithelium after several weeks. Recently, human tracheal xenografts have been developed in immunodeficient severe combined immunodeficiency (SCID and nude mice. In this review we recall that human airway cells implanted in such conditioned host grafts can regenerate a well-differentiated and functional human epithelium; we stress the interest in these humanized mice in assaying candidate progenitor and stem cells of the human airway mucosa.