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Sample records for autophagy influences glomerular

  1. Involvement of Endoplasmic Reticulum Stress, Autophagy, and Apoptosis in Advanced Glycation End Products-Induced Glomerular Mesangial Cell Injury

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    Chiang, Chih-Kang; Wang, Ching-Chia; Lu, Tien-Fong; Huang, Kuo-How; Sheu, Meei-Ling; Liu, Shing-Hwa; Hung, Kuan-Yu

    2016-01-01

    Advanced glycation end-products (AGEs)-induced mesangial cell death is one of major causes of glomerulus dysfunction in diabetic nephropathy. Both endoplasmic reticulum (ER) stress and autophagy are adaptive responses in cells under environmental stress and participate in the renal diseases. The role of ER stress and autophagy in AGEs-induced mesangial cell death is still unclear. Here, we investigated the effect and mechanism of AGEs on glomerular mesangial cells. AGEs dose-dependently decreased mesangial cell viability and induced cell apoptosis. AGEs also induced ER stress signals in a time- and dose-dependent manner. Inhibition of ER stress with 4-phenylbutyric acid effectively inhibited the activation of eIF2α and CHOP signals and reversed AGEs-induced cell apoptosis. AGEs also activated LC-3 cleavage, increased Atg5 expression, and decreased p62 expression, which indicated the autophagy induction in mesangial cells. Inhibition of autophagy by Atg5 siRNAs transfection aggravated AGEs-induced mesangial cell apoptosis. Moreover, ER stress inhibition by 4-phenylbutyric acid significantly reversed AGEs-induced autophagy, but autophagy inhibition did not influence the AGEs-induced ER stress-related signals activation. These results suggest that AGEs induce mesangial cell apoptosis via an ER stress-triggered signaling pathway. Atg5-dependent autophagy plays a protective role. These findings may offer a new strategy against AGEs toxicity in the kidney. PMID:27665710

  2. Glomerular number and function are influenced by spontaneous and induced low birth weight in rats

    DEFF Research Database (Denmark)

    Schreuder, Michiel F; Nyengaard, Jens Randel; Fodor, M;

    2005-01-01

    A link exists between low birth weight and diseases in adulthood, such as hypertension, cardiovascular disease, and insulin resistance. Intrauterine growth restriction (IUGR) has been used to explain this association and has been shown to lead to a nephron endowment in humans. A reduction...... in glomerular number has been described in animal models with induced low birth weight as well but not in animals with spontaneous low birth weight. It therefore is debatable whether the models are suitable. The effect on glomerular number and size was studied in rats with naturally occurring IUGR...... and experimental IUGR, induced by bilateral uterine artery ligation. Design-based stereologic methods were used. Urinary protein excretion was determined as a measure of renal damage. Results showed a decrease of approximately 20% in glomerular number in both groups of IUGR (control 35,400, naturally occurring...

  3. Insulin Influences Autophagy Response Distinctively in Macrophages of Different Compartments

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    Karen K. S. Sunahara

    2014-11-01

    Full Text Available Background/Aims: Diabetes mellitus (DM is characterized by hyperglycemia, associated to a lack or inefficiency of the insulin to regulate glucose metabolism. DM is also marked by alterations in a diversity of cellular processes that need to be further unraveled. In this study, we examined the autophagy pathway in diabetic rat macrophages before and after treatment with insulin. Methods: Bone marrow-derived macrophages (BMM, bronchoalveolar lavage (BAL and splenic tissue of diabetic male Wistar rats (alloxan, 42 mg/kg, i.v., 10 days and control rats (physiological saline, i.v.. Some diabetic rats were given neutral protamine Hagedorn insulin (4 IU, s.c. 8 h before experiments. For characterization of the model and evaluation of the effect of insulin on the autophagic process, the following analyzes were performed: (a concentrations of cytokines: interleukin (IL-1β, tumor necrosis factor (TNF-α, IL-6, IL-4, IL-10, cytokine-induced neutrophil chemoattractant (CINC-1 and CINC-2 in the BAL supernatant was measured by ELISA; (b characterization of alveolar macrophage (AM of the BAL as surface antigens (MHCII, pan-macrophage KiM2R, CD11b and autophagic markers (protein microtubule-associated light chain (LC3, autophagy protein (Atg12 by flow cytometry and confocal microscopy (c study of macrophages differentiated from the bone marrow by flow cytometry and confocal microscopy (d histology of the spleen by immunohistochemistry associated with confocal microscopy. Results: Interestingly, insulin exerted antagonistic effects on macrophages from different tissues. Macrophages from bronchoalveolar lavage (BAL enhanced their LC3 autophagosome bound content after treatment with insulin whereas splenic macrophages from red pulp in diabetic rats failed to enhance their Atg 12 levels compared to control animals. Insulin treatment in diabetic rats did not change LC3 content in bone marrow derived macrophages (BMM. M1 and M2 macrophages behaved accordingly to the

  4. Influences of combination of chemotherapy and autophagy inhibitor on the calreticulin expression in colon cancer cells

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    Rui-qing PENG

    2016-04-01

    Full Text Available Objective  To investigate the influence of chemotherapy combined with autophagy inhibitor on apoptosis and calreticulin (CRT expression on colonic cancer cells. Methods  The colon cancer cells HCT116 were taken as the target in the present study. The inhibition rates (IC50 of chemotherapeutics oxaliplatin, 5-Fu and SN-38 were assessed by MTT assay. The changes in CRT expression on the membrane of HCT116 and apoptosis were determined with flow cytometry before and after treatment with chemotherapeutics. CRT location in HCT116 was detected by fluorescent immunoassay before and after treatment with chemotherapeutic agents. The influence on HCT116 autophagy was determined by Western blotting after treatment with these chemotherapeutic agents. The changes in CRT expression on HCT116 membrane and apoptosis were determined with flow cytometry before and after treatment with the chemotherapeutics combined with autophagy inhibitor chloroquine (CQ. Results  The ratio of apoptosis and membrane expression of CRT were elevated 12 hours after treatment with Oxaliplatin, 5-Fu and SN38, but without statistical significance. Fluorescent immunoassay showed a transposition of CRT from cytoplasm to the membrane after oxaliplatin treatment. Western blotting revealed that oxaliplatin, 5Fu and SN38 induced autophagy of HCT116 cells, and the autophagy was inhibited by the addition of CQ. Flow cytometric analysis indicated that the percentages of annexin V+ cells and membrane expression of CRT were higher after treatment with the chemotherapy agents combined with CQ. The upregulation of CRT expression on membrane was obviously higher after treatment with oxaliplatin combined with CQ than that before the treatment with these agents (P=0.027. Conclusion  Oxaliplatin combined with CQ may increase the apoptosis rate of HCT116 cells and upregulate CRT expression in the membrane. DOI: 10.11855/j.issn.0577-7402.2016.04.03

  5. Glomerular disease

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    950356 Experimental studies of glomerular endothe- lial cell culture and its production of extracellular ma-trixes.CHEN Xiangmei(陈香美),et al.Dept Nephrol,Great Wall Hosp,Beijing,100853.Natl Med J China1995;75(1):25-27.We successfully cultured human fetal and bovineglomerular endothelial cells by cell cloning and main-

  6. Glomerular disease

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    2009222 Clinical significance and histological origin of glomerular epithelial proliferative lesion in patients with focal segmental glomerulosclerosis.SHI Sufang(师素芳),et al.Div Nephrol,Dep Med,Instit Nephrol,1st Hosp,Peking Univ,Beijing 100034.Chin J Naphrol,2009;25(3):181-186.

  7. Glomerular Diseases

    Science.gov (United States)

    ... Kidney Disease (CKD) What Is Chronic Kidney Disease? Causes of CKD Tests & Diagnosis Managing CKD Eating Right Preventing CKD ... kidney damage. Endocarditis sometimes produces chronic kidney disease (CKD). HIV, the virus that leads to AIDS, can also cause glomerular disease. Between 5 and 10 percent of ...

  8. Glomerular disease

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    939152 Determination of urine red blood cellvolume and their distribution curve for identify-ing the source of hematuria by automatic bloodcell counter.LI Shinqiang(李诗强),GUO Duis-han(郭兑山).2nd Affili Hosp,China Med U-niv.Chin J Nephrol 1992;8(4):196-198.The paper introduces the determination of urinered blood cells’ volume and their distributioncurve by automatic blood cell counter.Havingobserved the degrees of deformation in shape ofred cells in 106 cases,we found that when theurine red cells’ volume was≤60 fl and theirdistribution curve showed asymmetry,theywere glomerular hematuria,and when it was >61 f1 and showed symmetry or mixed.They

  9. Autophagy in Inflammatory Diseases

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    Alexander J. S. Choi

    2011-01-01

    Full Text Available Autophagy provides a mechanism for the turnover of cellular organelles and proteins through a lysosome-dependent degradation pathway. During starvation, autophagy exerts a homeostatic function that promotes cell survival by recycling metabolic precursors. Additionally, autophagy can interact with other vital processes such as programmed cell death, inflammation, and adaptive immune mechanisms, and thereby potentially influence disease pathogenesis. Macrophages deficient in autophagic proteins display enhanced caspase-1-dependent proinflammatory cytokine production and the activation of the inflammasome. Autophagy provides a functional role in infectious diseases and sepsis by promoting intracellular bacterial clearance. Mutations in autophagy-related genes, leading to loss of autophagic function, have been implicated in the pathogenesis of Crohn's disease. Furthermore, autophagy-dependent mechanisms have been proposed in the pathogenesis of several pulmonary diseases that involve inflammation, including cystic fibrosis and pulmonary hypertension. Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases associated with inflammation.

  10. Glomerular filtration rate

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    ... page: //medlineplus.gov/ency/article/007305.htm Glomerular filtration rate To use the sharing features on this page, please enable JavaScript. Glomerular filtration rate (GFR) is a test used to check ...

  11. Autophagy in Hepatic Fibrosis

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    Yang Song

    2014-01-01

    Full Text Available Hepatic fibrosis is a leading cause of morbidity and mortality worldwide. Hepatic fibrosis is usually associated with chronic liver diseases caused by infection, drugs, metabolic disorders, or autoimmune imbalances. Effective clinical therapies are still lacking. Autophagy is a cellular process that degrades damaged organelles or protein aggregation, which participates in many pathological processes including liver diseases. Autophagy participates in hepatic fibrosis by activating hepatic stellate cells and may participate as well through influencing other fibrogenic cells. Besides that, autophagy can induce some liver diseases to develop while it may play a protective role in hepatocellular abnormal aggregates related liver diseases and reduces fibrosis. With a better understanding of the potential effects of autophagy on hepatic fibrosis, targeting autophagy might be a novel therapeutic strategy for hepatic fibrosis in the near future.

  12. Structural determinants of glomerular permeability.

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    Deen, W M; Lazzara, M J; Myers, B D

    2001-10-01

    Recent progress in relating the functional properties of the glomerular capillary wall to its unique structure is reviewed. The fenestrated endothelium, glomerular basement membrane (GBM), and epithelial filtration slits form a series arrangement in which the flow diverges as it enters the GBM from the fenestrae and converges again at the filtration slits. A hydrodynamic model that combines morphometric findings with water flow data in isolated GBM has predicted overall hydraulic permeabilities that are consistent with measurements in vivo. The resistance of the GBM to water flow, which accounts for roughly half that of the capillary wall, is strongly dependent on the extent to which the GBM surfaces are blocked by cells. The spatial frequency of filtration slits is predicted to be a very important determinant of the overall hydraulic permeability, in keeping with observations in several glomerular diseases in humans. Whereas the hydraulic resistances of the cell layers and GBM are additive, the overall sieving coefficient for a macromolecule (its concentration in Bowman's space divided by that in plasma) is the product of the sieving coefficients for the individual layers. Models for macromolecule filtration reveal that the individual sieving coefficients are influenced by one another and by the filtrate velocity, requiring great care in extrapolating in vitro observations to the living animal. The size selectivity of the glomerular capillary has been shown to be determined largely by the cellular layers, rather than the GBM. Controversial findings concerning glomerular charge selectivity are reviewed, and it is concluded that there is good evidence for a role of charge in restricting the transmural movement of albumin. Also discussed is an effect of albumin that has received little attention, namely, its tendency to increase the sieving coefficients of test macromolecules via steric interactions. Among the unresolved issues are the specific contributions of the

  13. Inducing autophagy

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    Harder, Lea M; Bunkenborg, Jakob; Andersen, Jens S.

    2014-01-01

    catabolism, which has recently been found to induce autophagy in an MTOR independent way and support cancer cell survival. In this study, quantitative phosphoproteomics was applied to investigate the initial signaling events linking ammonia to the induction of autophagy. The MTOR inhibitor rapamycin was used...

  14. Emerging role of podocyte autophagy in the progression of diabetic nephropathy.

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    Yasuda-Yamahara, Mako; Kume, Shinji; Tagawa, Atsuko; Maegawa, Hiroshi; Uzu, Takashi

    2015-01-01

    Glomerular podocytes are pivotal in maintaining glomerular filtration barrier function. As severe podocyte injury results in proteinuria in patients with diabetic nephropathy, determining the pathogenesis of podocyte injury may contribute to the development of new treatments. We recently showed that autophagy is involved in the pathogenesis of diabetes-related podocyte injury. Insufficient podocyte autophagy and podocyte loss are observed in diabetic patients with massive proteinuria. Podocyte loss and massive proteinuria occur in high-fat diet-induced diabetic mice with podocyte-specific autophagy deficiency, with podocytes of these mice and of diabetic rats having huge damaged lysosomes. Sera from diabetic patients and from rodents with massive proteinuria cause autophagy insufficiency, resulting in lysosome dysfunction and apoptosis of cultured podocytes. These findings suggest the importance of autophagy in maintaining lysosome homeostasis in podocytes under diabetic conditions. Impaired autophagy may be involved in the pathogenesis of podocyte loss, leading to massive proteinuria in diabetic nephropathy.

  15. Precision autophagy: Will the next wave of selective autophagy markers and specific autophagy inhibitors feed clinical pipelines?

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    Lebovitz, Chandra B; DeVorkin, Lindsay; Bosc, Damien; Rothe, Katharina; Singh, Jagbir; Bally, Marcel; Jiang, Xiaoyan; Young, Robert N; Lum, Julian J; Gorski, Sharon M

    2015-01-01

    Research presented at the Vancouver Autophagy Symposium (VAS) 2014 suggests that autophagy's influence on health and disease depends on tight regulation and precision targeting of substrates. Discussions recognized a pressing need for robust biomarkers that accurately assess the clinical utility of modulating autophagy in disease contexts. Biomarker discovery could flow from investigations of context-dependent triggers, sensors, and adaptors that tailor the autophagy machinery to achieve target specificity. In his keynote address, Dr. Vojo Deretic (University of New Mexico) described the discovery of a cargo receptor family that utilizes peptide motif-based cargo recognition, a mechanism that may be more precise than generic substrate tagging. The keynote by Dr. Alec Kimmelman (Harvard Medical School) emphasized that unbiased screens for novel selective autophagy factors may accelerate the development of autophagy-based therapies. Using a quantitative proteomics screen for de novo identification of autophagosome substrates in pancreatic cancer, Kimmelman's group discovered a new type of selective autophagy that regulates bioavailable iron. Additional presentations revealed novel autophagy regulators and receptors in metabolic diseases, proteinopathies, and cancer, and outlined the development of specific autophagy inhibitors and treatment regimens that combine autophagy modulation with anticancer therapies. VAS 2014 stimulated interdisciplinary discussions focused on the development of biomarkers, drugs, and preclinical models to facilitate clinical translation of key autophagy discoveries.

  16. Glomerular Damage in Experimental Proliferative Glomerulonephritis Under Glomerular Capillary Hypertension

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    Pei-Rong Wang

    2015-03-01

    Full Text Available Background/Aims: Immunologically and hemodynamically mediated the destruction of glomerular architecture is thought to be the major causes of end-stage renal failure. The purpose of this study is to evaluate the effect of glomerular hypertension on glomerular injury and the progression of glomerular sclerosis after Thy-1 nephritis was induced. Method: Thy-1 nephritis was induced in the stroke-prone spontaneously hypertensive rat strain (SHR-SP (group SP and in age-matched Wistar-Kyoto (WKY (group WKY rats, following unilateral nephrectomy (UNX, and a vehicle was injected alone in UNX SHR-SP as control (group SC. Result: The degree of glomerular damage in response to a single dose of anti-thy-1 antibody, and its functional consequences (eg. proteinuria, diminished GFR are more pronounced in group SP than normotensive group WKY and hypertensive group SC without mesangial cell injury. While normotensive group WKY rats recovered completely from mesangial cell injury on day 28-42, glomeruli in group SP kept on persistent macrophage infiltration, α-SMA expression on day 42-56. In addition, glomerular capillary repair with the GECs was rarely seen in pronouncedly proliferative and sclerostic areas. The incidence of glomerular sclerosis and the level of proteinuria were markedly increased by day 56 in the group SP. Conclusions: Our results demonstrate that glomerular hypertension aggravate glomerular damage and glomerulosclerosis in this model of Thy 1 nephritis.

  17. Mechanisms of mitochondria and autophagy crosstalk.

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    Rambold, Angelika S; Lippincott-Schwartz, Jennifer

    2011-12-01

    Autophagy is a cellular survival pathway that recycles intracellular components to compensate for nutrient depletion and ensures the appropriate degradation of organelles. Mitochondrial number and health are regulated by mitophagy, a process by which excessive or damaged mitochondria are subjected to autophagic degradation. Autophagy is thus a key determinant for mitochondrial health and proper cell function. Mitophagic malfunction has been recently proposed to contribute to progressive neuronal loss in Parkinson's disease. In addition to autophagy's significance in mitochondrial integrity, several lines of evidence suggest that mitochondria can also substantially influence the autophagic process. The mitochondria's ability to influence and be influenced by autophagy places both elements (mitochondria and autophagy) in a unique position where defects in one or the other system could increase the risk to various metabolic and autophagic related diseases.

  18. The influence of autophagy on mouse inflammatory responses caused by Salmonella enterica serovar Typhimurium with spv genes

    Institute of Scientific and Technical Information of China (English)

    LI Yuan-Yuan; WU Shu-Yan; CHU Yuan-Yuan; LIAO LI; LIQiong; HUANG Rui

    2011-01-01

    An investigation into the effects of Salmonella plasmid virulence genes (spv) on autophagy,apoptosis,and inflammation was carried out in mice,using a strain of Salmonella enterica serovar Typhimurium (S.typhimurium) SR-11 carrying spv.Strain BRD509 without spy was used as a control.Results showed that the expression of autophagy protein Beclin-1 in the livers and spleens in the SR-11 group was lower than that in the BRD509 group,while the apoptosis protein,Caspase-3,was higher in the SR-11 group.Inflammatory cytokine levels [interleukin 12 (IL-12) and interferon γ (IFN-γ)] were higher in the SR-11 group compared with those in the BRD509 group since 4 d post-infection.In addition,we found an increase in severe pathological changes and larger viable bacterial amounts in livers and spleens in the SR-11 group.After intervention with autophagy agonist rapamycin (RAPA),Beclin-1 expression increased in both groups,while Caspase-3 expression was different between the two groups: Caspase-3 decreased in the SR-11 group but increased in the BRD509 group.Moreover,RAPA decreased cytokine levels,bacterial quantity and organ-related injury in the SR-11 group whereas RAPA increased cytokine levels and aggravated organ injury in the BRD509 group.Results from these studies suggest that S.typhimurium with spv genes may exacerbate infection by inhibiting autophagy and affecting the production of inflammatory cytokines.RAPA-enhanced autophagy may improve the secretion of cytokines in order to protect the host from damaging by Salmonella infection.Our study suggests that the regulation of cellular autophagy may play a role in the prevention and control of certain infectious diseases.

  19. Autophagy is involved in mouse kidney development and podocyte differentiation regulated by Notch signalling.

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    Zhang, Chuyue; Li, Wen; Wen, Junkai; Yang, Zhuo

    2017-02-03

    Podocyte dysfunction results in glomerular diseases accounted for 90% of end-stage kidney disease. The evolutionarily conserved Notch signalling makes a crucial contribution in podocyte development and function. However, the underlying mechanism of Notch pathway modulating podocyte differentiation remains less obvious. Autophagy, reported to be related with Notch signalling pathways in different animal models, is regarded as a possible participant during podocyte differentiation. Here, we found the dynamic changes of Notch1 were coincided with autophagy: they both increased during kidney development and podocyte differentiation. Intriguingly, when Notch signalling was down-regulated by DAPT, autophagy was greatly diminished, and differentiation was also impaired. Further, to better understand the relationship between Notch signalling and autophagy in podocyte differentiation, rapamycin was added to enhance autophagy levels in DAPT-treated cells, and as a result, nephrin was recovered and DAPT-induced injury was ameliorated. Therefore, we put forward that autophagy is involved in kidney development and podocyte differentiation regulated by Notch signalling.

  20. Influence of Radix Astragali, Hirudo, Hirudin and their Compound Medicated Serum on the Growth Cycle and Apoptosis of Glomerular Mesangial Cell in Rats

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    Xianzhi Ren

    2014-06-01

    Full Text Available Objective: To observe the effect of Radix Astragali (RA, hirudo, hirudin and their compound medicated serum on growth cycle and apoptosis of glomerular mesangial cells (GMCs in rats and their apoptotic morphology. Methods: The prepared cells were randomly divided into control group, hirudo group, hirudin group, RA group and compound group. Flow cytometer was used to detect the growth cycle and apoptosis of GMCs while Wright stain and microscope were applied for the observation of apoptotic cells. Results: RA, hirudo, hirudin and their compound medicated serum could maintain abundant GMCs in gap phase 0/1 (G0/G1 and improve apoptotic rate of GMCs, which had significant differences when compared with control group (P < 0.01. Additionally, they could improve GMCs apoptosis, and differences were significant in hirudo and formula groups when compared with control group (P < 0.01. Conclusion: Hirudo, hirudin, RA and their compound (containing hirudo and RA can effectively inhibit MC proliferation and promote GMCs apoptosis by stopping GMCs entering phase S of which the efficacy of compound is the best, followed by hirudo.

  1. Autophagy and neurodegenerative disorders

    Institute of Scientific and Technical Information of China (English)

    Evangelia Kesidou; Roza Lagoudaki; Olga Touloumi; Kyriaki-Nefeli Poulatsidou; Constantina Simeonidou

    2013-01-01

    Accumulation of aberrant proteins and inclusion bodies are hallmarks in most neurodegenerative diseases. Consequently, these aggregates within neurons lead to toxic effects, overproduction of reactive oxygen species and oxidative stress. Autophagy is a significant intracel ular mechanism that removes damaged organelles and misfolded proteins in order to maintain cel homeostasis. Excessive or insufficient autophagic activity in neurons leads to altered homeostasis and influences their survival rate, causing neurodegeneration. The review article provides an update of the role of autophagic process in representative chronic and acute neurodegenerative disorders.

  2. Autophagy, Metabolism, and Cancer.

    Science.gov (United States)

    White, Eileen; Mehnert, Janice M; Chan, Chang S

    2015-11-15

    Macroautophagy (autophagy hereafter) captures intracellular proteins and organelles and degrades them in lysosomes. The degradation breakdown products are released from lysosomes and recycled into metabolic and biosynthetic pathways. Basal autophagy provides protein and organelle quality control by eliminating damaged cellular components. Starvation-induced autophagy recycles intracellular components into metabolic pathways to sustain mitochondrial metabolic function and energy homeostasis. Recycling by autophagy is essential for yeast and mammals to survive starvation through intracellular nutrient scavenging. Autophagy suppresses degenerative diseases and has a context-dependent role in cancer. In some models, cancer initiation is suppressed by autophagy. By preventing the toxic accumulation of damaged protein and organelles, particularly mitochondria, autophagy limits oxidative stress, chronic tissue damage, and oncogenic signaling, which suppresses cancer initiation. This suggests a role for autophagy stimulation in cancer prevention, although the role of autophagy in the suppression of human cancer is unclear. In contrast, some cancers induce autophagy and are dependent on autophagy for survival. Much in the way that autophagy promotes survival in starvation, cancers can use autophagy-mediated recycling to maintain mitochondrial function and energy homeostasis to meet the elevated metabolic demand of growth and proliferation. Thus, autophagy inhibition may be beneficial for cancer therapy. Moreover, tumors are more autophagy-dependent than normal tissues, suggesting that there is a therapeutic window. Despite these insights, many important unanswered questions remain about the exact mechanisms of autophagy-mediated cancer suppression and promotion, how relevant these observations are to humans, and whether the autophagy pathway can be modulated therapeutically in cancer. See all articles in this CCR Focus section, "Cell Death and Cancer Therapy."

  3. 15.3.Glomerular disease

    Institute of Scientific and Technical Information of China (English)

    1992-01-01

    920147 The distribution of immunoglobu-lin light chain deposition in glomerular dis-rases.ZHOU Xijing (周希静),et al.1st Affil Hosp,Chin Med Univ.Chin J Nephrol 1991; 7 (4):214-215.Eighty-eight renal biopsies from various types

  4. The formation of multivesicular bodies in activated blastocysts is influenced by autophagy and FGF signaling in mice

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    Shin, Hyejin; Bang, Soyoung; Kim, Jiyeon; Jun, Jin Hyun; Song, Haengseok; Lim, Hyunjung Jade

    2017-01-01

    Dormant blastocysts during delayed implantation undergo autophagic activation, which is an adaptive response to prolonged survival in utero during less favorable environment. We observed that multivesicular bodies (MVBs) accumulate in the trophectoderm of dormant blastocysts upon activation for implantation. Since autophagosomes are shown to fuse with MVBs and efficient autophagic degradation requires functional MVBs, we examined if MVB formation in activated blastocysts are associated with protracted autophagic state during dormancy. We show here that autophagic activation during dormancy is one precondition for MVB formation in activated blastocysts. Furthermore, the blockade of FGF signaling with PD173074 partially interferes with MVB formation in these blastocysts, suggesting the involvement of FGFR signaling in this process. We believe that MVB formation in activated blastocysts after dormancy is a potential mechanism of clearing subcellular debris accumulated during prolonged autophagy. PMID:28155881

  5. Autophagy in Tuberculosis

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    Deretic, Vojo

    2014-01-01

    Autophagy as an immune mechanism controls inflammation and acts as a cell-autonomous defense against intracellular microbes including Mycobacterium tuberculosis. An equally significant role of autophagy is its anti-inflammatory and tissue-sparing function. This combination of antimicrobial and anti-inflammatory actions prevents active disease in animal models. In human populations, genetic links between autophagy, inflammatory bowel disease, and susceptibility to tuberculosis provide further support to these combined roles of autophagy. The autophagic control of M. tuberculosis and prevention of progressive disease provide novel insights into physiological and immune control of tuberculosis. It also offers host-based therapeutic opportunities because autophagy can be pharmacologically modulated. PMID:25167980

  6. The Impact of Autophagy on Cell Death Modalities

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    Stefan W. Ryter

    2014-01-01

    Full Text Available Autophagy represents a homeostatic cellular mechanism for the turnover of organelles and proteins, through a lysosome-dependent degradation pathway. During starvation, autophagy facilitates cell survival through the recycling of metabolic precursors. Additionally, autophagy can modulate other vital processes such as programmed cell death (e.g., apoptosis, inflammation, and adaptive immune mechanisms and thereby influence disease pathogenesis. Selective pathways can target distinct cargoes (e.g., mitochondria and proteins for autophagic degradation. At present, the causal relationship between autophagy and various forms of regulated or nonregulated cell death remains unclear. Autophagy can occur in association with necrosis-like cell death triggered by caspase inhibition. Autophagy and apoptosis have been shown to be coincident or antagonistic, depending on experimental context, and share cross-talk between signal transduction elements. Autophagy may modulate the outcome of other regulated forms of cell death such as necroptosis. Recent advances suggest that autophagy can dampen inflammatory responses, including inflammasome-dependent caspase-1 activation and maturation of proinflammatory cytokines. Autophagy may also act as regulator of caspase-1 dependent cell death (pyroptosis. Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases in which apoptosis or other forms of regulated cell death may play a cardinal role.

  7. Glomerular Filtration Barrier Assembly: An insight

    OpenAIRE

    Arif, Ehtesham; Nihalani, Deepak

    2013-01-01

    A glomerulus is the network of capillaries that resides in the Bowman’s capsule that functions as a filtration unit of kidney. The glomerular function ensures that essential plasma proteins are retained in blood and the filtrate is passed on as urine. The glomerular filtration assembly is composed of three main cellular barriers that are critical for the ultrafiltration process, the fenestrated endothelium, glomerular basement membrane and highly specialized podocytes. The podocytes along wit...

  8. Growth hormone and somatostatin in glomerular injury.

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    Baud, L; Fouqueray, B; Bellocq, A; Doublier, S; Dumoulin, A

    1999-01-01

    Among other neuropeptides and neurohormones, growth hormone (GH) and somatostatin (SRIF) have been shown to modulate the development of glomerular injury in various renal diseases. In particular, GH is implicated in the induction of glomerular hypertrophy and sclerosis in partial nephrectomy and diabetic nephropathy. While GH effects on glomerular hypertrophy are likely mediated by insulin-like growth factor I (IGF-I), GH effects on glomerular sclerosis are independent of IGF-I. Those effects rather require multiple signaling pathways functioning in series, e.g. angiotensin II binding preceding transforming growth factor beta (TGF-beta) release, or pro-inflammatory factor release preceding repair/scarring processes. In contrast with GH, SRIF administration prevents the development of glomerular lesions in experimental diabetes, partial nephrectomy and immune glomerulonephritis. Inhibitory effects of SRIF on glomerular hypotrophy may be through a decrease in GH secretion and/or IGF-I expression or through a direct blockade of glomerular cell proliferation. The mechanisms underlying the anti-inflammatory effects of SRIF are most likely a deactivation of inflammatory cells related in part to an upregulated response of these cells to glucocorticoids. Additional studies will be required to further define the role of GH and SRIF in the development of glomerular injury and, hence, to identify new targets for a therapeutic approach in glomerular diseases.

  9. Role of complement in glomerular diseases.

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    Mao, Song; Zhang, Jianhua

    2016-01-01

    The complement system, composed of nearly 30 proteins, is a key regulator of immunity. The complement system is critical for protecting hosts from invading pathogens. Dysregulation of this system is associated with susceptibility to infection and various autoimmune diseases. Furthermore, complement activation due to the defective regulation of the alternative pathway will induce glomerular diseases. Anti-complement therapy has been applied in various glomerular diseases. Signaling pathways might be very important in the pathogenesis of glomerular diseases. This review will give a relatively complete signaling pathway flowchart for complement and a comprehensive understanding of the underlying role of complement in glomerular diseases.

  10. Nanomaterials, Autophagy, and Lupus Disease.

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    Bianco, Alberto; Muller, Sylviane

    2016-01-19

    Nanoscale materials hold great promise in the therapeutic field. In particular, as carriers or vectors, they help bioactive molecules reach their primary targets. Furthermore, by themselves, certain nanomaterials-regarded as protective-can modulate particular metabolic pathways that are deregulated in pathological situations. They can also synergistically improve the effects of a payload drug. These properties are the basis of their appeal. However, nanoscale materials can also have intrinsic properties that limit their use, and this is the case for certain types of nanomaterials that influence autophagy. This property can be beneficial in some pathological settings, but in others, if the autophagic flux is already accelerated, it can be deleterious. This is notably the case for systemic lupus erythematosus (SLE) and other chronic inflammatory diseases, including certain neurological diseases. The nanomaterial-autophagy interaction therefore must be treated with caution for therapeutic molecules and peptides that require vectorization for their administration.

  11. Schistosomal glomerular disease (a review

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    Zilton A. Andrade

    1984-12-01

    Full Text Available In this review paper schistosomal glomerulopathy is defined as an immune-complex disease. The disease appears in 12-15 per cent of the individuals with hepatosplenic schistosomiasis. Portal hypertension with collateral circulation helps the by pass of the hepatic clearance process and the parasite antigens can bind to antibodies in the circulation and be trapped in the renal glomerulus. Chronic membranousproliferative glomerulonephritis is the most commom lesion present and the nephrotic syndrome is the usual form of clinical presentation. The disease can be experimentally produced, and schistosomal antigens and antibodies, as well as complement, can be demonstrated in the glomerular lesions. Specific treatment of schistosomiasis does not seem to alter the clinical course of schistosomal nephropathy.A glomerulopatia esquistossomotica e um exemplo de doenca causada por complexos imunes. Ela se manifesta em 12 a 15% dos portadores de forma hepato-eplenica da esquistossomose. A hipertensao porta, com circulacao colateral, facilita a ultrapassagem do filtro hepatico e os antigenos esquistossomoticos podem se acoplar aos anticorpos na circulacao e vir a se depositar nos glomerulos. O tipo histologico mais frequente e a glomerulonefrite cronica membrano-proliferativa, geralmente com sindrome nefrotica. A doenca e passivel de reproducao experimental e os antigenos esquistossomoticos, os anticorpos e fracoes do complemento podem ser demonstrados nas lesoes glomerulares. O tratamento especifico da esquistossomose nao mostrou ate o momento a capacidade de alterar o curso da nefropatia.

  12. Oxidative stress in primary glomerular diseases

    DEFF Research Database (Denmark)

    Markan, Suchita; Kohli, Harbir Singh; Sud, Kamal;

    2008-01-01

    To evaluate the status of oxidative stress in patients with different primary glomerular diseases (PGD) which have differential predisposition to renal failure.......To evaluate the status of oxidative stress in patients with different primary glomerular diseases (PGD) which have differential predisposition to renal failure....

  13. Autophagy and cancer

    Institute of Scientific and Technical Information of China (English)

    Si-Zhao; Lu; Duygu; Dee; Harrison-Findik

    2013-01-01

    Autophagy is a homeostatic and evolutionarily conserved mechanism of self-digestion by which the cells degrade and recycle long-lived proteins and excess or damaged organelles.Autophagy is activated in response to both physiological and pathological stimuli including growth factor depletion,energy deficiency or the upregulation of Bcl-2 protein expression.A novel role of autophagy in various cancers has been proposed.Interestingly,evidence that supports both a positive and negative role of autophagy in the pathogenesis of cancer has been reported.As a tumor suppression mechanism,autophagy maintains genome stability,induces senescence and possibly autophagic cell death.On the other hand,autophagy participates in tumor growth and maintenance by supplying metabolic substrate,limiting oxidative stress,and maintaining cancer stem cell population.It has been proposed that the differential roles of autophagy in cancer are disease type and stage specific.In addition,substrate selectivity might be involved in carrying out the specific effect of autophagy in cancer,and represents one of the potential directions for future studies.

  14. Influence of Autophagy Regulation Agent on the Proliferation of Toxoplasma Gondii in Mice%自噬调控剂对小鼠体内弓形虫增殖的影响

    Institute of Scientific and Technical Information of China (English)

    张琼; 张婧; 高劲松; 李万峰; 汪学龙

    2016-01-01

    Objective:To study the influence of autophagy regulation agent on the proliferation of toxo-plasma gondii in mice.Methods:Using autophagy inhibitors bafilomycin A1 and autophagy iinducing agent lithium chloride respectively to intervene toxoplasma gondii infected mice.Fluorescence quantitative PCR was used to detect proliferation of Toxoplasma gondii under different experimental conditions.Results:Quantita-tive PCR results showed that bafilomycin A1 dose and the number of toxoplasma gondii in mice was negative correlated,while inducing agent lithium chloride and the number of toxoplasma gondii in mice was positive correlated.Conclusion:The regulation on autophagy of host cells in mice could regulate the proliferation and replication of toxoplasma gondii.%目的::研究自噬调控剂对小鼠体内弓形虫增殖的影响。方法:建立弓形虫感染的小鼠模型,分别使用自噬抑制剂巴弗洛霉 A1(bafilomycin A1)和自噬诱导剂氯化锂对弓形虫感染小鼠模型进行干预,应用荧光定量 PCR 检测不同实验条件下弓形虫数量。结果:实验结果表明巴弗洛霉素 A1剂量与小鼠体内弓形虫数量呈负相关,而诱导剂氯化锂与小鼠体内弓形虫数量呈正相关。结论:调控宿主细胞自噬可调控体内弓形虫增殖。

  15. Autophagy and ethanol neurotoxicity.

    Science.gov (United States)

    Luo, Jia

    2014-01-01

    Excessive ethanol exposure is detrimental to the brain. The developing brain is particularly vulnerable to ethanol such that prenatal ethanol exposure causes fetal alcohol spectrum disorders (FASD). Neuronal loss in the brain is the most devastating consequence and is associated with mental retardation and other behavioral deficits observed in FASD. Since alcohol consumption during pregnancy has not declined, it is imperative to elucidate the underlying mechanisms and develop effective therapeutic strategies. One cellular mechanism that acts as a protective response for the central nervous system (CNS) is autophagy. Autophagy regulates lysosomal turnover of organelles and proteins within cells, and is involved in cell differentiation, survival, metabolism, and immunity. We have recently shown that ethanol activates autophagy in the developing brain. The autophagic preconditioning alleviates ethanol-induced neuron apoptosis, whereas inhibition of autophagy potentiates ethanol-stimulated reactive oxygen species (ROS) and exacerbates ethanol-induced neuroapoptosis. The expression of genes encoding proteins required for autophagy in the CNS is developmentally regulated; their levels are much lower during an ethanol-sensitive period than during an ethanol-resistant period. Ethanol may stimulate autophagy through multiple mechanisms; these include induction of oxidative stress and endoplasmic reticulum stress, modulation of MTOR and AMPK signaling, alterations in BCL2 family proteins, and disruption of intracellular calcium (Ca2+) homeostasis. This review discusses the most recent evidence regarding the involvement of autophagy in ethanol-mediated neurotoxicity as well as the potential therapeutic approach of targeting autophagic pathways.

  16. Role of autophagy in the pathogenesis of multiple sclerosis.

    Science.gov (United States)

    Liang, Peizhou; Le, Weidong

    2015-08-01

    Autophagy plays an important role in maintaining the cellular homeostasis. One of its functions is to degrade unnecessary organelles and proteins for energy recycling or amino-acids for cell survival. Ablation of autophagy leads to neurodegeneration. Multiple sclerosis (MS), a permanent neurological impairment typical of chronic inflammatory demyelinating disorder, is an auto-immune disease of the central nervous system (CNS). Autophagy is tightly linked to the innate and adaptive immune systems during the autoimmune process, and several studies have shown that autophagy directly participates in the progress of MS or experimental autoimmune encephalomyelitis (EAE, a mouse model of MS). Dysfunction of mitochondria that intensively influences the autophagy pathway is one of the important factors in the pathogenesis of MS. Autophagy-related gene (ATG) 5 and immune-related GTPase M (IRGM) 1 are increased, while ATG16L2 is decreased, in T-cells in EAE and active relapsing-remitting MS brains. Administration of rapamycin, an inhibitor of mammalian target of rapamycin ( mTOR), ameliorates relapsing-remitting EAE. Inflammation and oxidative stress are increased in MS lesions and EAE, but Lamp2 and the LC3-II/LC3-I ratio are decreased. Furthermore, autophagy in various glial cells plays important roles in regulating neuro-inflammation in the CNS, implying potential roles in MS. In this review, we discuss the role of autophagy in the peripheral immune system and the CNS in neuroinflammation associated with the pathogenesis of MS.

  17. Anti- and pro-tumor functions of autophagy.

    Science.gov (United States)

    Morselli, Eugenia; Galluzzi, Lorenzo; Kepp, Oliver; Vicencio, José-Miguel; Criollo, Alfredo; Maiuri, Maria Chiara; Kroemer, Guido

    2009-09-01

    Autophagy constitutes one of the major responses to stress in eukaryotic cells, and is regulated by a complex network of signaling cascades. Not surprisingly, autophagy is implicated in multiple pathological processes, including infection by pathogens, inflammatory bowel disease, neurodegeneration and cancer. Both oncogenesis and tumor survival are influenced by perturbations of the molecular machinery that controls autophagy. Numerous oncoproteins, including phosphatidylinositol 3-kinase, Akt1 and anti-apoptotic members of the Bcl-2 family suppress autophagy. Conversely, several tumor suppressor proteins (e.g., Atg4c; beclin 1; Bif-1; BH3-only proteins; death-associated protein kinase 1; LKB1/STK11; PTEN; UVRAG) promote the autophagic pathway. This does not entirely apply to p53, one of the most important tumor suppressor proteins, which regulates autophagy in an ambiguous fashion, depending on its subcellular localization. Irrespective of the controversial role of p53, basal levels of autophagy appear to inhibit tumor development. On the contrary, chemotherapy- and metabolic stress-induced activation of the autophagic pathway reportedly contribute to the survival of formed tumors, thereby favoring resistance. In this context, autophagy inhibition would represent a major therapeutic target for chemosensitization. Here, we will review the current knowledge on the dual role of autophagy as an anti- and pro-tumor mechanism.

  18. Crosstalk in glomerular injury and repair

    DEFF Research Database (Denmark)

    Dimke, Henrik; Maezawa, Yoshiro; Quaggin, Susan E

    2015-01-01

    PURPOSE OF REVIEW: The glomerulus is a unique structure required for filtration of blood, while retaining plasma proteins based on size and charge selectivity. Distinct cell types form the structural unit that creates the filtration barrier. Structurally, fenestrated endothelial cells line...... the capillary loops and lie in close contact with mesangial cells. Podocytes are connected by specialized intercellular junctions known as slit diaphragms and separated from the endothelial compartment by the glomerular basement membrane. In order for this highly specialized structure to function, cross...... the glomerular filtration unit. We will highlight recent findings of cellular crosstalk via signaling pathways that regulate glomerular barrier function in pathophysiological conditions....

  19. Innate Immune Activity in Glomerular Podocytes

    Science.gov (United States)

    Xia, Hong; Bao, Wenduona; Shi, Shaolin

    2017-01-01

    Glomerular podocytes are specialized in structure and play an essential role in glomerular filtration. In addition, podocyte stress can initiate glomerular damage by inducing the injury of other glomerular cell types. Studies have shown that podocytes possess the property of immune cells and may be involved in adaptive immunity. Emerging studies have also shown that podocytes possess signaling pathways of innate immune responses and that innate immune responses often result in podocyte injury. More recently, mitochondrial-derived damage-associated molecular patterns (mtDAMPs) have been shown to play a critical role in a variety of pathological processes in cells. In the present mini-review, we summarize the recent advances in the studies of innate immunity and its pathogenic role in podocytes, particularly, from the perspective of mtDAMPs. PMID:28228761

  20. The Glomerular Filtration Barrier: Components and Crosstalk

    Directory of Open Access Journals (Sweden)

    Madhav C. Menon

    2012-01-01

    Full Text Available The glomerular filtration barrier is a highly specialized blood filtration interface that displays a high conductance to small and midsized solutes in plasma but retains relative impermeability to macromolecules. Its integrity is maintained by physicochemical and signalling interplay among its three core constituents—the glomerular endothelial cell, the basement membrane and visceral epithelial cell (podocyte. Understanding the pathomechanisms of inherited and acquired human diseases as well as experimental injury models of this barrier have helped to unravel this interdependence. Key among the consequences of interference with the integrity of the glomerular filtration barrier is the appearance of significant amounts of proteins in the urine. Proteinuria correlates with kidney disease progression and cardiovascular mortality. With specific reference to proteinuria in human and animal disease phenotypes, the following review explores the roles of the endothelial cell, glomerular basement membrane, and the podocyte and attempts to highlight examples of essential crosstalk within this barrier.

  1. Chemical Inhibition of Autophagy

    DEFF Research Database (Denmark)

    Baek, Eric; Lin Kim, Che; Gyeom Kim, Mi;

    2016-01-01

    Chinese hamster ovary (CHO) cells activate and undergo apoptosis and autophagy for various environmental stresses. Unlike apoptosis, studies on increasing the production of therapeutic proteins in CHO cells by targeting the autophagy pathway are limited. In order to identify the effects of chemical...... autophagy inhibitors on the specific productivity (qp), nine chemical inhibitors that had been reported to target three different phases of autophagy (metformin, dorsomorphin, resveratrol, and SP600125 against initiation and nucleation; 3-MA, wortmannin, and LY294002 against elongation, and chloroquine...... and bafilomycin A1 against autophagosome fusion) were used to treat three recombinant CHO (rCHO) cell lines: the Fc-fusion protein-producing DG44 (DG44-Fc) and DUKX-B11 (DUKX-Fc) and antibody-producing DG44 (DG44-Ab) cell lines. Among the nine chemical inhibitors tested, 3-MA, dorsomorphin, and SP600125...

  2. Autophagy and cytokines.

    Science.gov (United States)

    Harris, James

    2011-11-01

    Autophagy is a highly conserved homoeostatic mechanism for the lysosomal degradation of cytosolic constituents, including long-lived macromolecules, organelles and intracellular pathogens. Autophagosomes are formed in response to a number of environmental stimuli, including amino acid deprivation, but also by both host- and pathogen-derived molecules, including toll-like receptor ligands and cytokines. In particular, IFN-γ, TNF-α, IL-1, IL-2, IL-6 and TGF-β have been shown to induce autophagy, while IL-4, IL-10 and IL-13 are inhibitory. Moreover, autophagy can itself regulate the production and secretion of cytokines, including IL-1, IL-18, TNF-α, and Type I IFN. This review discusses the potentially pivotal roles of autophagy in the regulation of inflammation and the coordination of innate and adaptive immune responses.

  3. The Glomerular Filtration Barrier: Components and Crosstalk

    OpenAIRE

    Madhav C. Menon; Chuang, Peter Y.; Cijiang John He

    2012-01-01

    The glomerular filtration barrier is a highly specialized blood filtration interface that displays a high conductance to small and midsized solutes in plasma but retains relative impermeability to macromolecules. Its integrity is maintained by physicochemical and signalling interplay among its three core constituents—the glomerular endothelial cell, the basement membrane and visceral epithelial cell (podocyte). Understanding the pathomechanisms of inherited and acquired human diseases as well...

  4. De novo glomerular diseases after renal transplantation.

    Science.gov (United States)

    Ponticelli, Claudio; Moroni, Gabriella; Glassock, Richard J

    2014-08-07

    Glomerular diseases developing in the kidney allograft are more often recurrences of the original disease affecting the native kidneys. However, in an undefined number of cases de novo, glomerular diseases unrelated to the original disease in the native kidneys can develop in the transplanted kidney. The clinical presentation and histologic features of de novo diseases are often similar to those features observed in patients with primary or secondary GN in the native kidneys. However, in transplanted kidneys, the glomerular, vascular, and tubulointerstitial changes are often intertwined with structural abnormalities already present at the time of transplant or caused by antibody- or cell-mediated allograft rejection, immunosuppressive drugs, or superimposed infection (most often of a viral nature). The pathophysiology of de novo glomerular diseases is quite variable. In rare cases of de novo minimal change disease, circulating factors increasing the glomerular permeability likely participate. Maladaptive hemodynamic changes and tissue fibrosis caused by calcineurin inhibitors or other factors may be involved in the pathogenesis of de novo FSGS. The exposure of cryptic podocyte antigens may favor the development of de novo membranous nephropathy. Many cases of de novo membranoproliferative GN are related to hepatitis C virus infection. Patients with Alport syndrome lacking antigenic epitopes in their glomerular basement membrane may develop antibodies against these glomerular basement membrane antigens expressed in the transplanted kidney. Infection may cause acute GN to have a heterogeneous clinical presentation and outcome. De novo pauci-immune GN in renal transplant is rare. Preexisting or acquired intolerance to glucose may, in the long term, cause diabetic nephropathy. The prognosis of de novo diseases depends on the type of GN, the severity of lesions caused by the alloimmune response, or the efficacy of immunosuppressive therapy. In most cases, the management

  5. Expression of glomerular ecto-ATPase in idiopathic nephrotic syndrome

    NARCIS (Netherlands)

    Cheung, PK; Baller, JFW; vanderHorst, MLC; Bakker, WW; Plesner, L; Kirley, TL; Knowles, AF

    1997-01-01

    The pathogenesis of glomerular alterations leading to increased glomerular permeability in disorders like Minimal Change Disease (MCD) is obscure. One of the preliminary observed glomerular alterations in MCD involves diminished expression of glomerular ecto-ATP-diphosphohydrolase (denoted as ecto-A

  6. Reactive oxygen species as glomerular autacoids.

    Science.gov (United States)

    Baud, L; Fouqueray, B; Philippe, C; Ardaillou, R

    1992-04-01

    There is considerable evidence suggesting that reactive oxygen species (ROS; superoxide anion, hydrogen peroxide, hydroxyl radical, hypochlorous acid) are implicated in the pathogenesis of toxic, ischemic, and immunologically mediated glomerular injury. The capacity of glomerular cells, especially mesangial cells, to generate ROS in response to several stimuli suggests that these autacoids may play a role in models of glomerular injury that are independent of infiltrating polymorphonuclear leukocytes and monocytes. The mechanisms whereby ROS formation results in morphologic lesions and in modifications of glomerular permeability, blood flow, and filtration rate have been inferred from in vitro studies. They involve direct and indirect injury to resident cells (mesangiolysis) and glomerular basement membrane (in concert with metalloproteases) and alteration of both the release and binding of vasoactive substances, such as bioactive lipids (e.g., prostaglandin E2, prostacyclin, thromboxane), cytokines (e.g., tumor necrosis factor alpha), and possibly endothelium-derived relaxing factor. The importance of such processes appears to be modulated by the intrinsic antioxidant defenses of the glomeruli. Further studies are needed to address the role of ROS in human glomerular diseases.

  7. Autophagy in Trypanosomatids

    Directory of Open Access Journals (Sweden)

    Paul A. M. Michels

    2012-07-01

    Full Text Available Autophagy is a ubiquitous eukaryotic process that also occurs in trypanosomatid parasites, protist organisms belonging to the supergroup Excavata, distinct from the supergroup Opistokontha that includes mammals and fungi. Half of the known yeast and mammalian AuTophaGy (ATG proteins were detected in trypanosomatids, although with low sequence conservation. Trypanosomatids such as Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. are responsible for serious tropical diseases in humans. The parasites are transmitted by insects and, consequently, have a complicated life cycle during which they undergo dramatic morphological and metabolic transformations to adapt to the different environments. Autophagy plays a major role during these transformations. Since inhibition of autophagy affects the transformation, survival and/or virulence of the parasites, the ATGs offer promise for development of drugs against tropical diseases. Furthermore, various trypanocidal drugs have been shown to trigger autophagy-like processes in the parasites. It is inferred that autophagy is used by the parasites in an—not always successful—attempt to cope with the stress caused by the toxic compounds.

  8. Autophagy research: Lessons from metabolism

    NARCIS (Netherlands)

    A.J. Meijer

    2009-01-01

    Autophagy research continues to expand exponentially. Clearly autophagy and metabolism are intimately connected; however, the rapid expansion of research into this topic inevitably brings the risk that important basic knowledge of metabolism will be overlooked when considering experimental data. Unf

  9. Influence of renal function on the measurement of glomerular filtration rate with Gates method%肾功能对Gates法肾小球滤过率实测值的影响

    Institute of Scientific and Technical Information of China (English)

    杨仪; 唐军; 田金玲; 陆文栋; 刘增礼

    2012-01-01

    Objective To investigate the influence of renal function on the measurement of glomerular filtration rate(GFR) with Gates method. Methods In 155 cases with different kidney disease(95 male, 60 female; 19-83 years old) , having impairment of re-nal function to varying degrees,renal dynamic imaging was performed by 99Tcm-DTPA and GFR was measured twice using Gates method both by two different manipulators in 73 cases and by the same manipulator at more than 3 months interval in 82 cases. Two groups of cases were divided into A stages according to mean GFR. All GFR at different stages in two groups were analyzed with the matched t-test to reveal if there were significant differences between the before-and-after GFR measured by different manipulators or by same manipulator at different time. Coefficient of variation(CV) of GFR at different stages was obtained to explore the rela-tionship between CV and renal function(mean GFR). Results There were not statistically significant differences of GFR between the before-and-after GFR measured by different manipulators or by same manipulator at different time in all cases(P>0. 05). With decline of renal function from stage Ⅰ to stage Ⅳ of chronic kidney disease(CKD) ,CV became larger. They were in negative corre-lation and the regression equations were Y= -0. 09X+10. 22(r=0. 60)by two different manipulators and Y= - 0. 11X311. 23(r = 0. 66)by the same manipulator. Conclusion Deviation at different extent in measuring GFR with Gates method exists at different stages of renal function. The worse the renal function is,the greater the deviation rises.%目的 探讨肾功能对Gates法测定肾小球滤过率(GFR)实测值的影响.方法 对155例慢性肾脏病(CKD)患者进行99Tcm-DTPA肾动态显像,采用Gates法测定GFR,其中73例由两位不同操作者进行肾脏ROI的勾画,82例由同一操作者在不同的时间进行两次ROI勾画,将所得的GFR进行分析比较,观察在不同的肾功能状态下由于肾

  10. Measuring glomerular number from kidney MRI images

    Science.gov (United States)

    Thiagarajan, Jayaraman J.; Natesan Ramamurthy, Karthikeyan; Kanberoglu, Berkay; Frakes, David; Bennett, Kevin; Spanias, Andreas

    2016-03-01

    Measuring the glomerular number in the entire, intact kidney using non-destructive techniques is of immense importance in studying several renal and systemic diseases. Commonly used approaches either require destruction of the entire kidney or perform extrapolation from measurements obtained from a few isolated sections. A recent magnetic resonance imaging (MRI) method, based on the injection of a contrast agent (cationic ferritin), has been used to effectively identify glomerular regions in the kidney. In this work, we propose a robust, accurate, and low-complexity method for estimating the number of glomeruli from such kidney MRI images. The proposed technique has a training phase and a low-complexity testing phase. In the training phase, organ segmentation is performed on a few expert-marked training images, and glomerular and non-glomerular image patches are extracted. Using non-local sparse coding to compute similarity and dissimilarity graphs between the patches, the subspace in which the glomerular regions can be discriminated from the rest are estimated. For novel test images, the image patches extracted after pre-processing are embedded using the discriminative subspace projections. The testing phase is of low computational complexity since it involves only matrix multiplications, clustering, and simple morphological operations. Preliminary results with MRI data obtained from five kidneys of rats show that the proposed non-invasive, low-complexity approach performs comparably to conventional approaches such as acid maceration and stereology.

  11. Autophagy in mammalian cells

    Institute of Scientific and Technical Information of China (English)

    Kadija; Abounit; Tiziano; M; Scarabelli; Roy; B; McCauley

    2012-01-01

    Autophagy is a regulated process for the degradation of cellular components that has been well conserved in eukaryotic cells. The discovery of autophagy-regulating proteins in yeast has been important in understanding this process. Although many parallels exist between fungi and mammals in the regulation and execution of autophagy, there are some important differences. The preautophagosomal structure found in yeast has not been identified in mammals, and it seems that there may be multiple origins for autophagosomes, including endoplasmic reticulum, plasma membrane and mitochondrial outer membrane. The maturation of the phagophore is largely dependent on 5’-AMP activated protein kinase and other factors that lead to the dephosphorylation of mammalian target of rapamycin. Once the process is initiated, the mammalian phagophore elongates and matures into an autophagosome by processes that are similar to those in yeast. Cargo selection is dependent on the ubiquitin conjugation of protein aggregates and organelles and recognition of these conjugates by autophagosomal receptors. Lysosomal degradation of cargo produces metabolites that can be recycled during stress. Autophagy is an impor-tant cellular safeguard during starvation in all eukaryotes; however, it may have more complicated, tissue specific roles in mammals. With certain exceptions, autophagy seems to be cytoprotective, and defects in the process have been associated with human disease.

  12. The interplays between autophagy and apoptosis induced by enterovirus 71.

    Directory of Open Access Journals (Sweden)

    Xueyan Xi

    Full Text Available BACKGROUND: Enterovirus 71 (EV71 is the causative agent of human diseases with distinct severity, from mild hand, foot and mouth disease to severe neurological syndromes, such as encephalitis and meningitis. The lack of understanding of viral pathogenesis as well as lack of efficient vaccine and drugs against this virus impedes the control of EV71 infection. EV71 virus induces autophagy and apoptosis; however, the relationship between EV71-induced autophagy and apoptosis as well as the influence of autophagy and apoptosis on virus virulence remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: In this study, it was observed that the Anhui strain of EV71 induced autophagy and apoptosis in human rhabdomyosarcoma (RD-A cells. Additionally, by either applying chemical inhibitors or knocking down single essential autophagic or apoptotic genes, inhibition of EV71 induced autophagy inhibited the apoptosis both at the autophagosome formation stage and autophagy execution stage. However, inhibition of autophagy at the stage of autophagosome and lysosome fusion promoted apoptosis. In reverse, the inhibition of EV71-induced apoptosis contributed to the conversion of microtubule-associated protein 1 light chain 3-I (LC3-I to LC3-II and degradation of sequestosome 1 (SQSTM1/P62. Furthermore, the inhibition of autophagy in the autophagsome formation stage or apoptosis decreased the release of EV71 viral particles. CONCLUSIONS/SIGNIFICANCE: In conclusion, the results of this study not only revealed novel aspect of the interplay between autophagy and apoptosis in EV71 infection, but also provided a new insight to control EV71 infection.

  13. Calcium Homeostasis and ER Stress in Control of Autophagy in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Elżbieta Kania

    2015-01-01

    Full Text Available Autophagy is a basic catabolic process, serving as an internal engine during responses to various cellular stresses. As regards cancer, autophagy may play a tumor suppressive role by preserving cellular integrity during tumor development and by possible contribution to cell death. However, autophagy may also exert oncogenic effects by promoting tumor cell survival and preventing cell death, for example, upon anticancer treatment. The major factors influencing autophagy are Ca2+ homeostasis perturbation and starvation. Several Ca2+ channels like voltage-gated T- and L-type channels, IP3 receptors, or CRAC are involved in autophagy regulation. Glucose transporters, mainly from GLUT family, which are often upregulated in cancer, are also prominent targets for autophagy induction. Signals from both Ca2+ perturbations and glucose transport blockage might be integrated at UPR and ER stress activation. Molecular pathways such as IRE 1-JNK-Bcl-2, PERK-eIF2α-ATF4, or ATF6-XBP 1-ATG are related to autophagy induced through ER stress. Moreover ER molecular chaperones such as GRP78/BiP and transcription factors like CHOP participate in regulation of ER stress-mediated autophagy. Autophagy modulation might be promising in anticancer therapies; however, it is a context-dependent matter whether inhibition or activation of autophagy leads to tumor cell death.

  14. Hepatitis B virus x protein induces autophagy via activating death-associated protein kinase.

    Science.gov (United States)

    Zhang, H-T; Chen, G G; Hu, B-G; Zhang, Z-Y; Yun, J-P; He, M-L; Lai, P B S

    2014-01-01

    Hepatitis B virus x protein (HBX), a product of hepatitis B virus (HBV), is a multifunctional protein that regulates viral replication and various cellular functions. Recently, HBX has been shown to induce autophagy; however, the responsible mechanism is not fully known. In this study, we established stable HBX-expressing epithelial Chang cells as the platform to study how HBX induced autophagy. The results showed that the overexpression of HBX resulted in starvation-induced autophagy. HBX-induced autophagy was related to its ability to dephosphorylate/activate death-associated protein kinase (DAPK). The block of DAPK by its siRNA significantly counteracted HBX-mediated autophagy, confirming the positive role of DAPK in this process. HBX also induced Beclin 1, which functions at the downstream of the DAPK-mediated autophagy pathway. Although HBX could activate JNK, a kinase known to participate in autophagy in certain conditions, the change in JNK failed to influence HBX-induced autophagy. In conclusion, HBX induces autophagy via activating DAPK in a pathway related to Beclin 1, but not JNK. This new finding should help us to understand the role of autophagy in HBX-mediated pathogenesis and thus may provide targets for intervening HBX-related disorders.

  15. Inflammasome-independent modulation of cytokine response by autophagy in human cells.

    Directory of Open Access Journals (Sweden)

    Tania O Crişan

    Full Text Available Autophagy is a cell housekeeping mechanism that has recently received attention in relation to its effects on the immune response. Genetic studies have identified candidate loci for Crohn's disease susceptibility among autophagy genes, while experiments in murine macrophages from ATG16L1 deficient mice have shown that disruption of autophagy increases processing of IL-1β and IL-18 through an inflammasome-dependent manner. Using complementary approaches either inducing or inhibiting autophagy, we describe modulatory effects of autophagy on proinflammatory cytokine production in human cells. Inhibition of basal autophagy in human peripheral blood mononuclear cells (PBMCs significantly enhances IL-1β after stimulation with TLR2 or TLR4 ligands, while at the same time reducing the production of TNFα. In line with this, induction of autophagy by starvation inhibited IL-1β production. These effects of autophagy were not exerted at the processing step, as inflammasome activation was not influenced. In contrast, the effect of autophagy on cytokine production was on transcription level, and possibly involving the inhibition of p38 mitogen activated protein kinase (MAPK phosphorylation. In conclusion, autophagy modulates the secretion of proinflammatory cytokines in human cells through an inflammasome-independent pathway, and this is a novel mechanism that may be targeted in inflammatory diseases.

  16. Rapamycin upregulates autophagy by inhibiting the mTOR-ULK1 pathway, resulting in reduced podocyte injury.

    Directory of Open Access Journals (Sweden)

    Lingling Wu

    Full Text Available The podocyte functions as a glomerular filtration barrier. Autophagy of postmitotic cells is an important protective mechanism that is essential for maintaining the homeostasis of podocytes. Exploring an in vivo rat model of passive Heymann nephritis and an in vitro model of puromycin amino nucleotide (PAN-cultured podocytes, we examined the specific mechanisms underlying changing autophagy levels and podocyte injury. In the passive Heymann nephritis model rats, the mammalian target-of-rapamycin (mTOR levels were upregulated in injured podocytes while autophagy was inhibited. In PAN-treated podocytes, mTOR lowered the level of autophagy through the mTOR-ULK1 pathway resulting in damaged podocytes. Rapamycin treatment of these cells reduced podocyte injury by raising the levels of autophagy. These in vivo and in vitro experiments demonstrate that podocyte injury is associated with changes in autophagy levels, and that rapamycin can reduce podocyte injury by increasing autophagy levels via inhibition of the mTOR-ULK1 pathway. These results provide an important theoretical basis for future treatment of diseases involving podocyte injury.

  17. Autophagy in periodontitis patients and gingival fibroblasts: unraveling the link between chronic diseases and inflammation

    Directory of Open Access Journals (Sweden)

    Bullon Pedro

    2012-10-01

    Full Text Available Abstract Background Periodontitis, the most prevalent chronic inflammatory disease, has been related to cardiovascular diseases. Autophagy provides a mechanism for the turnover of cellular organelles and proteins through a lysosome-dependent degradation pathway. The aim of this research was to study the role of autophagy in peripheral blood mononuclear cells from patients with periodontitis and gingival fibroblasts treated with a lipopolysaccharide of Porphyromonas gingivalis. Autophagy-dependent mechanisms have been proposed in the pathogenesis of inflammatory disorders and in other diseases related to periodontitis, such as cardiovascular disease and diabetes. Thus it is important to study the role of autophagy in the pathophysiology of periodontitis. Methods Peripheral blood mononuclear cells from patients with periodontitis (n = 38 and without periodontitis (n = 20 were used to study autophagy. To investigate the mechanism of autophagy, we evaluated the influence of a lipopolysaccharide from P. gingivalis in human gingival fibroblasts, and autophagy was monitored morphologically and biochemically. Autophagosomes were observed by immunofluorescence and electron microscopy. Results We found increased levels of autophagy gene expression and high levels of mitochondrial reactive oxygen species production in peripheral blood mononuclear cells from patients with periodontitis compared with controls. A significantly positive correlation between both was observed. In human gingival fibroblasts treated with lipopolysaccharide from P. gingivalis, there was an increase of protein and transcript of autophagy-related protein 12 (ATG12 and microtubule-associated protein 1 light chain 3 alpha LC3. A reduction of mitochondrial reactive oxygen species induced a decrease in autophagy whereas inhibition of autophagy in infected cells increased apoptosis, showing the protective role of autophagy. Conclusion Results from the present study suggest that autophagy

  18. Glomerular latency coding in artificial olfaction

    Directory of Open Access Journals (Sweden)

    Jaber eAl Yamani

    2012-01-01

    Full Text Available Sensory perception results from the way sensory information is subsequently transformed in the brain. Olfaction is a typical example in which odor representations undergo considerable changes as they pass from olfactory receptor neurons (ORNs to second-order neurons. First, many ORNs expressing the same receptor protein yet presenting heterogeneous dose-response properties converge onto individually identifiable glomeruli. Second, onset latency of glomerular activation is believed to play a role in encoding odor quality and quantity in the context of fast information processing. Taking inspiration from the olfactory pathway, we designed a simple yet robust glomerular latency coding scheme for processing gas sensor data. The proposed bio-inspired approach was evaluated using an in-house Sn02 sensor array. Glomerular convergence was achieved by noting the possible analogy between receptor protein expressed in ORNs and metal catalyst used across the fabricated gas sensor array. Ion implantation was another technique used to account both for sensor heterogeneity and enhanced sensitivity. The response of the gas sensor array was mapped into glomerular latency patterns, whose rank order is concentration-invariant. Gas recognition was achieved by simply looking for a match within a library of spatio-temporal spike fingerprints. Because of its simplicity, this approach enables the integration of sensing and processing onto a single-chip.

  19. Dopamine Oxidation and Autophagy

    Directory of Open Access Journals (Sweden)

    Patricia Muñoz

    2012-01-01

    Full Text Available The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome has been proposed to play an essential role in the degeneration of dopaminergic neurons containing neuromelanin by inducing mitochondrial dysfunction, oxidative stress, the formation of neurotoxic α-synuclein protofibrils, and impaired protein degradation. Here, we discuss the relationship between the oxidation of dopamine to aminochrome, the precursor of neuromelanin, autophagy dysfunction in dopaminergic neurons containing neuromelanin, and the role of dopamine oxidation to aminochrome in autophagy dysfunction in dopaminergic neurons. Aminochrome induces the following: (i the formation of α-synuclein protofibrils that inactivate chaperone-mediated autophagy; (ii the formation of adducts with α- and β-tubulin, which induce the aggregation of the microtubules required for the fusion of autophagy vacuoles and lysosomes.

  20. DNA damage and autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely [Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583 (United States); Panayiotidis, Mihalis I. [School of Community Health Sciences, University of Nevada, Reno, NV 89557 (United States); Franco, Rodrigo, E-mail: rfrancocruz2@unl.edu [Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583 (United States)

    2011-06-03

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  1. Nutritional Status and Cardiac Autophagy

    Directory of Open Access Journals (Sweden)

    Jihyun Ahn

    2013-02-01

    Full Text Available Autophagy is necessary for the degradation of long-lasting proteins and nonfunctional organelles, and is activated to promote cellular survival. However, overactivation of autophagy may deplete essential molecules and organelles responsible for cellular survival. Lifelong calorie restriction by 40% has been shown to increase the cardiac expression of autophagic markers, which suggests that it may have a cardioprotective effect by decreasing oxidative damage brought on by aging and cardiovascular diseases. Although cardiac autophagy is critical to regulating protein quality and maintaining cellular function and survival, increased or excessive autophagy may have deleterious effects on the heart under some circumstances, including pressure overload-induced heart failure. The importance of autophagy has been shown in nutrient supply and preservation of energy in times of limitation, such as ischemia. Some studies have suggested that a transition from obesity to metabolic syndrome may involve progressive changes in myocardial inflammation, mitochondrial dysfunction, fibrosis, apoptosis, and myocardial autophagy.

  2. Autophagy and lysosomal dysfunction as emerging mechanisms of nanomaterial toxicity

    Directory of Open Access Journals (Sweden)

    Stern Stephan T

    2012-06-01

    Full Text Available Abstract The study of the potential risks associated with the manufacture, use, and disposal of nanoscale materials, and their mechanisms of toxicity, is important for the continued advancement of nanotechnology. Currently, the most widely accepted paradigms of nanomaterial toxicity are oxidative stress and inflammation, but the underlying mechanisms are poorly defined. This review will highlight the significance of autophagy and lysosomal dysfunction as emerging mechanisms of nanomaterial toxicity. Most endocytic routes of nanomaterial cell uptake converge upon the lysosome, making the lysosomal compartment the most common intracellular site of nanoparticle sequestration and degradation. In addition to the endo-lysosomal pathway, recent evidence suggests that some nanomaterials can also induce autophagy. Among the many physiological functions, the lysosome, by way of the autophagy (macroautophagy pathway, degrades intracellular pathogens, and damaged organelles and proteins. Thus, autophagy induction by nanoparticles may be an attempt to degrade what is perceived by the cell as foreign or aberrant. While the autophagy and endo-lysosomal pathways have the potential to influence the disposition of nanomaterials, there is also a growing body of literature suggesting that biopersistent nanomaterials can, in turn, negatively impact these pathways. Indeed, there is ample evidence that biopersistent nanomaterials can cause autophagy and lysosomal dysfunctions resulting in toxicological consequences.

  3. Targeting autophagy in neurodegenerative diseases.

    Science.gov (United States)

    Vidal, René L; Matus, Soledad; Bargsted, Leslie; Hetz, Claudio

    2014-11-01

    The most prevalent neurodegenerative disorders involve protein misfolding and the aggregation of specific proteins. Autophagy is becoming an attractive target to treat neurodegenerative disorders through the selective degradation of abnormally folded proteins by the lysosomal pathway. However, accumulating evidence indicates that autophagy impairment at different regulatory steps may contribute to the neurodegenerative process. Thus, a complex scenario is emerging where autophagy may play a dual role in neurodegenerative diseases by causing the downstream effect of promoting the degradation of misfolded proteins and an upstream effect where its deregulation perturbs global proteostasis, contributing to disease progression. Challenges in the future development of therapeutic strategies to target the autophagy pathway are discussed.

  4. Low birth weight influences glomerular filtration rate:a meta analysis%低出生体重影响肾小球滤过率的荟萃分析

    Institute of Scientific and Technical Information of China (English)

    许戎; 左力; 王海燕

    2008-01-01

    目的 研究比较低出生体重对肾小球滤过率的远期影响.方法 以"birth weight"、"creatinine clearance"、"glomerular filtration rate"、"renal function"对Pubmed所有文献进行检索.按筛选标准共有7篇文献入选.使用Revman4.2进行统计分析.结果 低出生体重者肾小球滤过率较低,约比正常出生体重者降低4ml/(min·1.73m2),剔除以儿童为观察对象的研究后,结果 仍显示低出生体重者肾小球滤过率较低,约比正常出生体重者降低3~4ml/(min·1.73m2).结论 低出生体重者要儿童期以后虽然肾小球滤过率在正常范围,但已比正常出生体重者有降低.

  5. Symptomatic hyponatremia during glomerular filtration rate testing

    OpenAIRE

    2010-01-01

    Hyponatremia affects nearly one in five of all hospitalized patients. Severe hyponatremia is associated with significant morbidity and mortality, and is therefore important to recognize. Prior reports have linked duloxetine with hyponatremia, but it is uncommon. In this case report, we describe a research subject taking duloxetine who developed severe symptomatic hyponatremia during glomerular filtration rate testing despite having undergone such testing uneventfully in the past.

  6. Amino acid metabolism inhibits antibody-driven kidney injury by inducing autophagy.

    Science.gov (United States)

    Chaudhary, Kapil; Shinde, Rahul; Liu, Haiyun; Gnana-Prakasam, Jaya P; Veeranan-Karmegam, Rajalakshmi; Huang, Lei; Ravishankar, Buvana; Bradley, Jillian; Kvirkvelia, Nino; McMenamin, Malgorzata; Xiao, Wei; Kleven, Daniel; Mellor, Andrew L; Madaio, Michael P; McGaha, Tracy L

    2015-06-15

    Inflammatory kidney disease is a major clinical problem that can result in end-stage renal failure. In this article, we show that Ab-mediated inflammatory kidney injury and renal disease in a mouse nephrotoxic serum nephritis model was inhibited by amino acid metabolism and a protective autophagic response. The metabolic signal was driven by IFN-γ-mediated induction of indoleamine 2,3-dioxygenase 1 (IDO1) enzyme activity with subsequent activation of a stress response dependent on the eIF2α kinase general control nonderepressible 2 (GCN2). Activation of GCN2 suppressed proinflammatory cytokine production in glomeruli and reduced macrophage recruitment to the kidney during the incipient stage of Ab-induced glomerular inflammation. Further, inhibition of autophagy or genetic ablation of Ido1 or Gcn2 converted Ab-induced, self-limiting nephritis to fatal end-stage renal disease. Conversely, increasing kidney IDO1 activity or treating mice with a GCN2 agonist induced autophagy and protected mice from nephritic kidney damage. Finally, kidney tissue from patients with Ab-driven nephropathy showed increased IDO1 abundance and stress gene expression. Thus, these findings support the hypothesis that the IDO-GCN2 pathway in glomerular stromal cells is a critical negative feedback mechanism that limits inflammatory renal pathologic changes by inducing autophagy.

  7. Autophagy: Regulation by Energy Sensing

    NARCIS (Netherlands)

    A.J. Meijer; P. Codogno

    2011-01-01

    Autophagy is inhibited by the mTOR signaling pathway, which is stimulated by increased amino acid levels. When cellular energy production is compromised, AMP-activated protein kinase is activated, mTOR is inhibited and autophagy is stimulated. Two recent studies have shed light on the molecular mech

  8. Regulation of Autophagy by Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda, E-mail: alakananda.basu@unthsc.edu [Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

    2011-06-09

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets.

  9. Neuronal autophagy in cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Feng Xu; Jin-Hua Gu; Zheng-Hong Qin

    2012-01-01

    Autophagy has evolved as a conserved process for the bulk degradation and recycling of cytosolic components,such as long-lived proteins and organelles.In neurons,autophagy is important for homeostasis and protein quality control and is maintained at relatively low levels under normal conditions,while it is upregulated in response to pathophysiological conditions,such as cerebral ischemic injury.However,the role of autophagy is more complex.It depends on age or brain maturity,region,severity of insult,and the stage of ischemia.Whether autophagy plays a beneficial or a detrimental role in cerebral ischemia depends on various pathological conditions.In this review,we elucidate the role of neuronal autophagy in cerebral ischemia.

  10. Complex regulation of autophagy in cancer - integrated approaches to discover the networks that hold a double-edged sword.

    Science.gov (United States)

    Kubisch, János; Türei, Dénes; Földvári-Nagy, László; Dunai, Zsuzsanna A; Zsákai, Lilian; Varga, Máté; Vellai, Tibor; Csermely, Péter; Korcsmáros, Tamás

    2013-08-01

    Autophagy, a highly regulated self-degradation process of eukaryotic cells, is a context-dependent tumor-suppressing mechanism that can also promote tumor cell survival upon stress and treatment resistance. Because of this ambiguity, autophagy is considered as a double-edged sword in oncology, making anti-cancer therapeutic approaches highly challenging. In this review, we present how systems-level knowledge on autophagy regulation can help to develop new strategies and efficiently select novel anti-cancer drug targets. We focus on the protein interactors and transcriptional/post-transcriptional regulators of autophagy as the protein and regulatory networks significantly influence the activity of core autophagy proteins during tumor progression. We list several network resources to identify interactors and regulators of autophagy proteins. As in silico analysis of such networks often necessitates experimental validation, we briefly summarize tractable model organisms to examine the role of autophagy in cancer. We also discuss fluorescence techniques for high-throughput monitoring of autophagy in humans. Finally, the challenges of pharmacological modulation of autophagy are reviewed. We suggest network-based concepts to overcome these difficulties. We point out that a context-dependent modulation of autophagy would be favored in anti-cancer therapy, where autophagy is stimulated in normal cells, while inhibited only in stressed cancer cells. To achieve this goal, we introduce the concept of regulo-network drugs targeting specific transcription factors or miRNA families identified with network analysis. The effect of regulo-network drugs propagates indirectly through transcriptional or post-transcriptional regulation of autophagy proteins, and, as a multi-directional intervention tool, they can both activate and inhibit specific proteins in the same time. The future identification and validation of such regulo-network drug targets may serve as novel intervention

  11. Autophagy in heart disease: a strong hypothesis for an untouched metabolic reserve.

    Science.gov (United States)

    Loos, B; Lochner, A; Engelbrecht, A-M

    2011-07-01

    Autophagy is a conserved catabolic process for long-lived proteins and organelles and is primarily responsible for nonspecific degradation of redundant or faulty cell components. Although autophagy has been described as the cell's major adaptive strategy in response to metabolic challenges, its influence on the cell's energy profile is poorly understood. In the myocardium, autophagy is active at basal levels and is crucial for maintaining its contractile function. Defects in the autophagic machinery cause cardiac dysfunction and heart failure. In this paper we propose that (1) autophagy contributes significantly to the metabolic balance sheet of the heart. (2) Increased autophagy contributes to an improved myocardial energy profile through changing the cardiac substrate preference. (3) Substrates generated through autophagy give rise to an alternative for ATP production with an oxygen-sparing effect. These elements identify autophagy in a new context of myocardial metabolic interregulation, which we discuss in the settings of myocardial infarction, heart failure and the diabetic heart. It is hoped that the hypothesis presented can lead to new insights aimed at exploiting autophagy to improve existing metabolic-based therapy in heart disease.

  12. Angiotensin Ⅱ promotes the expression of glomerular IQGAP1 and apoptosis of glomerular cells

    Institute of Scientific and Technical Information of China (English)

    刘以鹏

    2013-01-01

    Objective To evaluate the effects of AngⅡon the expression of IQ domain GTPase-activating protein1(IQ-GAP1) and apoptosis of glomerular cells,and to explorethe role of IQGAP1in AngⅡ-induced apoptosis of

  13. Glomerular immunoglobulin deposits induce glomerular inflammation in pregnant but not in non-pregnant rats

    NARCIS (Netherlands)

    Faas, MM; Van Der Schaaf, G; Schipper, M; Moes, H

    2003-01-01

    PROBLEM: Does an inflammatory stimulus evoke a more intense inflammatory response in pregnant rats as compared with nonpregnant rats? METHOD OF STUDY: Non-pregnant rats were injected with antibodies against the glomerular basement membrane (GBM), 14 days before pregnancy, to induce a subclinical glo

  14. Definition of glomerular antigens by monoclonal antibodies produced against a human glomerular membrane fraction.

    Science.gov (United States)

    Neale, T J; Callus, M S; Donovan, L C; Baird, H

    1990-10-01

    Experimental animal models of glomerulonephritis (GN) produced by direct antibody binding to non-basement membrane glomerular capillary wall antigens do not to date have human parallels. To examine the potential for this form of humoral glomerular injury in man, we sought to define discrete human non-GBM glomerular antigenic targets using hybridoma technology. Mice were immunised intraperitoneally with 20-100 micrograms of a human glomerular membrane fraction (HGMF). Six fusions have yielded 12 stable reagents defined by positive glomerular indirect immunofluorescence (IF) and microELISA using HGMF as the screening antigen. Subclass analysis of ascitic McAbs indicated several IgG1, one IgG2b, and three IgM reagents. Distinctive IF patterns of reactivity with epithelial, endothelial or mesangial structures have been observed, with or without peritubular capillary, tubular basement membrane and vessel wall reactivity. Seven normal non-renal human organs and the kidneys of rat, rabbit and sheep have shown patterns characteristic of each individual McAb, restricted to human or with species cross reactivity. To partially characterise McAb-reactive antigens, detergent-solubilised renal cortex and collagenase-solubilised GBM (CS-GBM) extracts have been probed by immunoblot. A unique McAb 7-5Q, reactive with glomerular and tubular epithelial structures, binds major bands of approximately 107 KD and 93 KD in detergent solubilised cortex and a single band of similar size by immunoprecipitation (110 KD). 5-3A (a human-restricted linear-reacting McAb) binds bands of 20-200 KD (major band 58 KD) in CS-GBM. In conclusion, distinct species-restricted and more broadly disposed glomerular epitopes are definable in man by McAbs and are potential targets for humoral injury. Purification of these antigens will allow assay for circulating putative nephritogenic auto-antibody and potentially, McAbs may be useful in screening urine for evidence of occult structural renal disease.

  15. Creatinine clearance as a substitute for the glomerular filtration rate in the assessment of glomerular hemodynamics.

    Science.gov (United States)

    Okada, N; Imanishi, M; Yoshioka, K; Konishi, Y; Okumura, M; Tanaka, S; Fujii, S

    1999-11-01

    A method for the clinical assessment of glomerular hemodynamics has been published previously. We here examined whether, when using this method, renal creatinine clearance (Ccr) can be substituted for the glomerular filtration rate (GFR). The study subjects comprised 57 inpatients from Osaka City General Hospital: 30 with type 2 diabetes mellitus and 27 with chronic glomerulonephritis. During the 2-wk study, patients received a high-salt diet for 1 wk and a low-salt diet for 1 wk. Urinary sodium excretion and systemic blood pressure were measured daily. The renal plasma flow, Ccr, and plasma total protein concentration were also evaluated simultaneously on the last day of the high-salt diet. The GFR was also calculated from the fractional renal accumulation of 99mTc-diethylenetriaminepentaacetic acid (DTPA). Glomerular hemodynamics, represented by the glomerular capillary hydraulic pressure and the resistance of afferent and efferent arterioles, were calculated using the renal clearance, the plasma total protein concentration, and the pressure-natriuresis relationship. Values for renal hemodynamics with the Ccr-derived GFR were compared with those from the 99mTc-DTPA-derived GFR. Ccr values of 53 to 169 ml/min correlated with the 99mTc-DTPA-derived clearance of 39 to 179 ml/min (n=57, r=.71, presistances of afferent and efferent arterioles calculated using the Ccr-derived GFR correlated significantly with those calculated using the 99mTc-DTPA-derived GFR (r=.99, p<.001 and r=.99, p<.001, respectively). These results indicate that the Ccr is an accurate representation of the GFR for use in glomerular hemodynamic analysis of the pressure-natriuresis relationship.

  16. Defective Autophagy Initiates Malignant Transformation.

    Science.gov (United States)

    Galluzzi, Lorenzo; Bravo-San Pedro, José Manuel; Kroemer, Guido

    2016-05-19

    In this issue of Molecular Cell, Park et al. (2016) elegantly demonstrate that a partial defect in autophagy supports malignant transformation as it favors the production of genotoxic reactive oxygen species by mitochondria.

  17. Multiphoton imaging of the glomerular permeability of angiotensinogen.

    Science.gov (United States)

    Nakano, Daisuke; Kobori, Hiroyuki; Burford, James L; Gevorgyan, Haykanush; Seidel, Saskia; Hitomi, Hirofumi; Nishiyama, Akira; Peti-Peterdi, Janos

    2012-11-01

    Patients and animals with renal injury exhibit increased urinary excretion of angiotensinogen. Although increased tubular synthesis of angiotensinogen contributes to the increased excretion, we do not know to what degree glomerular filtration of systemic angiotensinogen, especially through an abnormal glomerular filtration barrier, contributes to the increase in urinary levels. Here, we used multiphoton microscopy to visualize and quantify the glomerular permeability of angiotensinogen in the intact mouse and rat kidney. In healthy mice and Munich-Wistar-Frömter rats at the early stage of glomerulosclerosis, the glomerular sieving coefficient of systemically infused Atto565-labeled human angiotensinogen (Atto565-hAGT), which rodent renin cannot cleave, was only 25% of the glomerular sieving coefficient of albumin, and its urinary excretion was undetectable. In a more advanced phase of kidney disease, the glomerular permeability of Atto565-hAGT was slightly higher but still very low. Furthermore, unlike urinary albumin, the significantly higher urinary excretion of endogenous rat angiotensinogen did not correlate with either the Atto565-hAGT or Atto565-albumin glomerular sieving coefficients. These results strongly suggest that the vast majority of urinary angiotensinogen originates from the tubules rather than glomerular filtration.

  18. Autophagy in DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Piotr Czarny

    2015-01-01

    Full Text Available DNA damage response (DDR involves DNA repair, cell cycle regulation and apoptosis, but autophagy is also suggested to play a role in DDR. Autophagy can be activated in response to DNA-damaging agents, but the exact mechanism underlying this activation is not fully understood, although it is suggested that it involves the inhibition of mammalian target of rapamycin complex 1 (mTORC1. mTORC1 represses autophagy via phosphorylation of the ULK1/2–Atg13–FIP200 complex thus preventing maturation of pre-autophagosomal structures. When DNA damage occurs, it is recognized by some proteins or their complexes, such as poly(ADPribose polymerase 1 (PARP-1, Mre11–Rad50–Nbs1 (MRN complex or FOXO3, which activate repressors of mTORC1. SQSTM1/p62 is one of the proteins whose levels are regulated via autophagic degradation. Inhibition of autophagy by knockout of FIP200 results in upregulation of SQSTM1/p62, enhanced DNA damage and less efficient damage repair. Mitophagy, one form of autophagy involved in the selective degradation of mitochondria, may also play role in DDR. It degrades abnormal mitochondria and can either repress or activate apoptosis, but the exact mechanism remains unknown. There is a need to clarify the role of autophagy in DDR, as this process may possess several important biomedical applications, involving also cancer therapy.

  19. Macrophage Autophagy in Atherosclerosis

    Directory of Open Access Journals (Sweden)

    Maria Chiara Maiuri

    2013-01-01

    Full Text Available Macrophages play crucial roles in atherosclerotic immune responses. Recent investigation into macrophage autophagy (AP in atherosclerosis has demonstrated a novel pathway through which these cells contribute to vascular inflammation. AP is a cellular catabolic process involving the delivery of cytoplasmic contents to the lysosomal machinery for ultimate degradation and recycling. Basal levels of macrophage AP play an essential role in atheroprotection during early atherosclerosis. However, AP becomes dysfunctional in the more advanced stages of the pathology and its deficiency promotes vascular inflammation, oxidative stress, and plaque necrosis. In this paper, we will discuss the role of macrophages and AP in atherosclerosis and the emerging evidence demonstrating the contribution of macrophage AP to vascular pathology. Finally, we will discuss how AP could be targeted for therapeutic utility.

  20. Gallium 67 scintigraphy in glomerular disease

    Energy Technology Data Exchange (ETDEWEB)

    Bakir, A.A.; Lopez-Majano, V.; Levy, P.S.; Rhee, H.L.; Dunea, G.

    1988-12-01

    To evaluate the diagnostic usefulness of gallium 67 scintigraphy in glomerular disease, 45 patients with various glomerulopathies, excluding lupus nephritis and renal vasculitis, were studied. Persistent renal visualization 48 hours after the gallium injection, a positive scintigram, was graded as + (less than), ++ (equal to), and +++ (greater than) the hepatic uptake. Positive scintigrams were seen in ten of 16 cases of focal segmental glomerulosclerosis, six of 11 cases of proliferative glomerulonephritis, and one case of minimal change, and one of two cases of membranous nephropathy; also in three of six cases of sickle glomerulopathy, two cases of diabetic neuropathy, one of two cases of amyloidosis, and one case of mild chronic allograft rejection. The 25 patients with positive scans were younger than the 20 with negative scans (31 +/- 12 v 42 +/- 17 years; P less than 0.01), and exhibited greater proteinuria (8.19 +/- 7.96 v 2.9 +/- 2.3 S/d; P less than 0.01) and lower serum creatinine values (2 +/- 2 v 4.1 +/- 2.8 mg/dL; P less than 0.01). The amount of proteinuria correlated directly with the intensity grade of the gallium image (P less than 0.02), but there was no correlation between the biopsy diagnosis and the outcome of the gallium scan. It was concluded that gallium scintigraphy is not useful in the differential diagnosis of the glomerular diseases under discussion. Younger patients with good renal function and heavy proteinuria are likely to have a positive renal scintigram regardless of the underlying glomerulopathy.

  1. Autophagy and Tumor%自噬与肿瘤

    Institute of Scientific and Technical Information of China (English)

    王宗鼎

    2011-01-01

    自噬(autophagy)作为细胞一种基本生物学特征,具有独特的形态学改变和特有的调控通路.近年来,自噬在关于对肿瘤的作用的研究已成为热点,在不同的种类肿瘤中,自噬扮演着不同的角色,分为促进和抑制肿瘤两种作用.自噬异常与人类恶性肿瘤的发生、发展联系紧密,其启动及调节与细胞能量代谢、微环境变化、抑癌基因及癌基因家族及复杂的信号调节等有关.清楚了解自噬的特点可为肿瘤治疗提供新的方向.%As a basic biological characteristic of cells, autophagy corresponds with specific morphological changes and a specific regulating pathways. In recent years autophagy has become a hot topic, in part due to its roles in both promoting and preventing neoplasms. Irregularities in autophagy in humans are closely linked to the occurrence of malignant neoplasms. Activation and regulation of autophagy influence not only cellular metabolism, but also microenvironments, antioncogene and oncogene function as well as complex signaling pathways. A clear understanding of autophagy would provide new approaches to the treatment of neoplasms.

  2. Fluorescence microscopy: A tool to study autophagy

    Science.gov (United States)

    Rai, Shashank; Manjithaya, Ravi

    2015-08-01

    Autophagy is a cellular recycling process through which a cell degrades old and damaged cellular components such as organelles and proteins and the degradation products are reused to provide energy and building blocks. Dysfunctional autophagy is reported in several pathological situations. Hence, autophagy plays an important role in both cellular homeostasis and diseased conditions. Autophagy can be studied through various techniques including fluorescence based microscopy. With the advancements of newer technologies in fluorescence microscopy, several novel processes of autophagy have been discovered which makes it an essential tool for autophagy research. Moreover, ability to tag fluorescent proteins with sub cellular targets has enabled us to evaluate autophagy processes in real time under fluorescent microscope. In this article, we demonstrate different aspects of autophagy in two different model organisms i.e. yeast and mammalian cells, with the help of fluorescence microscopy.

  3. Interactions between Autophagy and Inhibitory Cytokines.

    Science.gov (United States)

    Wu, Tian-Tian; Li, Wei-Min; Yao, Yong-Ming

    2016-01-01

    Autophagy is a degradative pathway that plays an essential role in maintaining cellular homeostasis. Most early studies of autophagy focused on its involvement in age-associated degeneration and nutrient deprivation. However, the immunological functions of autophagy have become more widely studied in recent years. Autophagy has been shown to be an intrinsic cellular defense mechanism in the innate and adaptive immune responses. Cytokines belong to a broad and loose category of proteins and are crucial for innate and adaptive immunity. Inhibitory cytokines have evolved to permit tolerance to self while also contributing to the eradication of invading pathogens. Interactions between inhibitory cytokines and autophagy have recently been reported, revealing a novel mechanism by which autophagy controls the immune response. In this review, we discuss interactions between autophagy and the regulatory cytokines IL-10, transforming growth factor-β, and IL-27. We also mention possible interactions between two newly discovered cytokines, IL-35 and IL-37, and autophagy.

  4. Autophagy and apoptosis: rivals or mates?

    Institute of Scientific and Technical Information of China (English)

    Yan Cheng; Jin-Ming Yang

    2013-01-01

    Autophagy,a cellular process of "self-eating" by which intracellular components are degraded within the lysosome,is an evolutionarily conserved response to various stresses.Autophagy is associated with numerous patho-physiological conditions,and dysregulation of autophagy contributes to the pathogenesis of a variety of human diseases including cancer.Depending on context,activation of autophagy may promote either cell survival or death,two major events that determine pathological process of many illnesses.Importantly,the activity of autophagy is often associated with apoptosis,another critical cellular process determining cellular fate.A better understanding of biology of autophagy and its implication in human health and disorder,as well as the relationship between autophagy and apoptosis,has the potential of facilitating the development of autophagy-based therapeutic interventions for human diseases such as cancer.

  5. Interactions between Autophagy and Inhibitory Cytokines

    Science.gov (United States)

    Wu, Tian-tian; Li, Wei-Min; Yao, Yong-Ming

    2016-01-01

    Autophagy is a degradative pathway that plays an essential role in maintaining cellular homeostasis. Most early studies of autophagy focused on its involvement in age-associated degeneration and nutrient deprivation. However, the immunological functions of autophagy have become more widely studied in recent years. Autophagy has been shown to be an intrinsic cellular defense mechanism in the innate and adaptive immune responses. Cytokines belong to a broad and loose category of proteins and are crucial for innate and adaptive immunity. Inhibitory cytokines have evolved to permit tolerance to self while also contributing to the eradication of invading pathogens. Interactions between inhibitory cytokines and autophagy have recently been reported, revealing a novel mechanism by which autophagy controls the immune response. In this review, we discuss interactions between autophagy and the regulatory cytokines IL-10, transforming growth factor-β, and IL-27. We also mention possible interactions between two newly discovered cytokines, IL-35 and IL-37, and autophagy. PMID:27313501

  6. Autophagy and mitophagy in cellular damage control

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2013-01-01

    Full Text Available Autophagy and mitophagy are important cellular processes that are responsible for breaking down cellular contents, preserving energy and safeguarding against accumulation of damaged and aggregated biomolecules. This graphic review gives a broad summary of autophagy and discusses examples where autophagy is important in controlling protein degradation. In addition we highlight how autophagy and mitophagy are involved in the cellular responses to reactive species and mitochondrial dysfunction. The key signaling pathways for mitophagy are described in the context of bioenergetic dysfunction.

  7. Evidence for restriction of fluid and solute movement across the glomerular capillary wall by the subpodocyte space.

    Science.gov (United States)

    Salmon, Andrew H J; Toma, Ildikó; Sipos, Arnold; Muston, P Robert; Harper, Steven J; Bates, David O; Neal, Christopher R; Peti-Peterdi, János

    2007-12-01

    The glomerular filtration barrier (GFB) is generally considered to consist of three layers: fenestrated glomerular endothelium, glomerular basement membrane, and filtration slits between adjacent podocyte foot processes. Detailed anatomic examination of the GFB has revealed a novel abluminal structure, the subpodocyte space (SPS), identified as the labyrinthine space between the underside of podocyte cell body/primary processes and the foot processes. The SPS covers 50-65% of the filtration surface of the GFB, indicating that SPS may influence glomerular permeability. We have examined the contribution of the SPS to the permeability characteristics of the GFB using multiphoton microscopy techniques in isolated, perfused glomeruli and in the intact kidney in vivo. SPS were identified using this technique, with comparable dimensions to SPS examined with electron microscopy. The passage of the intermediate-weight molecule rhodamine-conjugated 10-kDa dextran, but not the low-weight molecule lucifer yellow ( approximately 450 Da), accumulated in SPS-covered regions of the GFB, compared with GFB regions not covered by SPS ("naked regions"). Net lucifer yellow flux (taken to indicate fluid flux) through identifiable SPS regions was calculated to be 66-75% of that occurring through naked regions. These observations indicate both ultrafiltration and hydraulic resistance imparted by the SPS, demonstrating the potential physiological contribution of the SPS to glomerular permeability.

  8. Prevalence of Glomerular Diseases: King Khalid University Hospital, Saudi Arabia

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    Mitwalli A

    2000-01-01

    Full Text Available To obtain a more recent and comprehensive insight into the prevalence of glomerular diseases in our patient population, medical records of 200 patients with biopsy proven glomerulonephritis (GN, between January 1994 and June 1999, at the King Khalid University Hospital, Riyadh, Saudi Arabia were analyzed. Primary glomerular disease was found to be the most prevalent, accounting for 63.5% of all glomerular diseases. Among primary glomerular diseases, focal and segmental glomerulosclerosis (FSGS was the most common histological lesion (34.6% and was associated with a high prevalence of hypertension (86.4%, nephrotic syndrome (68.18%, hematuria (63.6% and renal functional impairment (27.3%. Mesangioproliferative GN was the second most common lesion (25.1% followed by mesangiocapillary GN (15.7%, IgA nephropathy (10.2%, and minimal change disease (8.5%. Amongst secondary glomerular diseases, lupus nephritis was the most prevalent (24.5%. In conclusion, primary glomerular diseases constituted the commonest group encountered and the prevalence of FSGS was quite high with male sex and young adults predominating. FSGS was also associated with a high prevalence of end-stage renal disease. Further collaborative studies are necessary to explore the predisposing factors and associations of glomerular disease, especially FSGS.

  9. Noncanonical autophagy inhibits the autoinflammatory, lupus-like response to dying cells.

    Science.gov (United States)

    Martinez, Jennifer; Cunha, Larissa D; Park, Sunmin; Yang, Mao; Lu, Qun; Orchard, Robert; Li, Quan-Zhen; Yan, Mei; Janke, Laura; Guy, Cliff; Linkermann, Andreas; Virgin, Herbert W; Green, Douglas R

    2016-05-01

    Defects in clearance of dying cells have been proposed to underlie the pathogenesis of systemic lupus erythematosus (SLE). Mice lacking molecules associated with dying cell clearance develop SLE-like disease, and phagocytes from patients with SLE often display defective clearance and increased inflammatory cytokine production when exposed to dying cells in vitro. Previously, we and others described a form of noncanonical autophagy known as LC3-associated phagocytosis (LAP), in which phagosomes containing engulfed particles, including dying cells, recruit elements of the autophagy pathway to facilitate maturation of phagosomes and digestion of their contents. Genome-wide association studies have identified polymorphisms in the Atg5 (ref. 8) and possibly Atg7 (ref. 9) genes, involved in both canonical autophagy and LAP, as markers of a predisposition for SLE. Here we describe the consequences of defective LAP in vivo. Mice lacking any of several components of the LAP pathway show increased serum levels of inflammatory cytokines and autoantibodies, glomerular immune complex deposition, and evidence of kidney damage. When dying cells are injected into LAP-deficient mice, they are engulfed but not efficiently degraded and trigger acute elevation of pro-inflammatory cytokines but not anti-inflammatory interleukin (IL)-10. Repeated injection of dying cells into LAP-deficient, but not LAP-sufficient, mice accelerated the development of SLE-like disease, including increased serum levels of autoantibodies. By contrast, mice deficient in genes required for canonical autophagy but not LAP do not display defective dying cell clearance, inflammatory cytokine production, or SLE-like disease, and, like wild-type mice, produce IL-10 in response to dying cells. Therefore, defects in LAP, rather than canonical autophagy, can cause SLE-like phenomena, and may contribute to the pathogenesis of SLE.

  10. Anti-tumor immunity, autophagy and chemotherapy

    Institute of Scientific and Technical Information of China (English)

    Gy(o)rgyi Müzes; Ferenc Sipos

    2012-01-01

    Autophagy or self-digestion of cells is activated upon various stressful stimuli and has been found to be a survival and drug resistance pathway in cancer.However,genetic studies support that autophagy can act as a tumor suppressor.Furthermore,defective autophagy is implicated in tumorigenesis,as well.The precise impact of autophagy on malignant transformation has not yet been clarified,but recent data suggest that this complex process is mainly directed by cell types,phases,genetic background and microenvironment.Relation of autophagy to anticancer immune responses may indicate a novel aspect in cancer chemotherapy.

  11. The cellular decision between apoptosis and autophagy

    Institute of Scientific and Technical Information of China (English)

    Yong-Jun Fan; Wei-Xing Zong

    2013-01-01

    Apoptosis and autophagy are important molecular processes that maintain organismal and cellular homeostasis,respectively.While apoptosis fulfills its role through dismantling damaged or unwanted cells,autophagy maintains cellular homeostasis through recycling selective intracellular organelles and molecules.Yet in some conditions,autophagy can lead to cell death.Apoptosis and autophagy can be stimulated by the same stresses.Emerging evidence indicates an interplay between the core proteins in both pathways,which underlies the molecular mechanism of the crosstalk between apoptosis and autophagy.This review summarizes recent literature on molecules that regulate both the apoptotic and autophagic processes.

  12. AUTOPHAGY AND IL-1 FAMILY CYTOKINES

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    James Harris

    2013-01-01

    Full Text Available Autophagy is an important intracellular homeostatic mechanism for the targeting of cytosolic constituents, including organelles, for lysosomal degradation. Autophagy plays roles in numerous physiological processes, include immune cell responses to endogenous and exogenous pathogenic stimuli. Moreover, autophagy has a potentially pivotal role in the regulation of inflammatory responses. In particular, autophagy regulates endogenous inflammasome activators, as well as inflammasome components and pro-IL-1β. This review focuses specifically on the role autophagy plays in regulating the production, processing and secretion of IL-1 family cytokines.

  13. Autophagy in sepsis: Degradation into exhaustion?

    Science.gov (United States)

    Ho, Jeffery; Yu, Jun; Wong, Sunny H; Zhang, Lin; Liu, Xiaodong; Wong, Wai T; Leung, Czarina C H; Choi, Gordon; Wang, Maggie H T; Gin, Tony; Chan, Matthew T V; Wu, William K K

    2016-07-01

    Autophagy is one of the innate immune defense mechanisms against microbial challenges. Previous in vitro and in vivo models of sepsis demonstrated that autophagy was activated initially in sepsis, followed by a subsequent phase of impairment. Autophagy modulation appears to be protective against multiple organ injuries in these murine sepsis models. This is achieved in part by preventing apoptosis, maintaining a balance between the productions of pro- and anti-inflammatory cytokines, and preserving mitochondrial functions. This article aims to discuss the role of autophagy in sepsis and the therapeutic potential of autophagy enhancers.

  14. Autophagy in cancer: good, bad, or both?

    Science.gov (United States)

    Hippert, Melanie M; O'Toole, Patrick S; Thorburn, Andrew

    2006-10-01

    Autophagy has been recognized as an important cellular process for at least 50 years; however, it is only with the recent identification of key regulators of autophagy (Atg genes) that we have begun a mechanistic exploration of its importance in cancer. Recent studies suggest that autophagy may be important in the regulation of cancer development and progression and in determining the response of tumor cells to anticancer therapy. However, the role of autophagy in these processes is complicated and may, depending on the circumstances, have diametrically opposite consequences for the tumor. In this article, we discuss recent discoveries regarding autophagy in cancer.

  15. IL13 activates autophagy to regulate secretion in airway epithelial cells.

    Science.gov (United States)

    Dickinson, John D; Alevy, Yael; Malvin, Nicole P; Patel, Khushbu K; Gunsten, Sean P; Holtzman, Michael J; Stappenbeck, Thaddeus S; Brody, Steven L

    2016-01-01

    Cytokine modulation of autophagy is increasingly recognized in disease pathogenesis, and current concepts suggest that type 1 cytokines activate autophagy, whereas type 2 cytokines are inhibitory. However, this paradigm derives primarily from studies of immune cells and is poorly characterized in tissue cells, including sentinel epithelial cells that regulate the immune response. In particular, the type 2 cytokine IL13 (interleukin 13) drives the formation of airway goblet cells that secrete excess mucus as a characteristic feature of airway disease, but whether this process is influenced by autophagy was undefined. Here we use a mouse model of airway disease in which IL33 (interleukin 33) stimulation leads to IL13-dependent formation of airway goblet cells as tracked by levels of mucin MUC5AC (mucin 5AC, oligomeric mucus/gel forming), and we show that these cells manifest a block in mucus secretion in autophagy gene Atg16l1-deficient mice compared to wild-type control mice. Similarly, primary-culture human tracheal epithelial cells treated with IL13 to stimulate mucus formation also exhibit a block in MUC5AC secretion in cells depleted of autophagy gene ATG5 (autophagy-related 5) or ATG14 (autophagy-related 14) compared to nondepleted control cells. Our findings indicate that autophagy is essential for airway mucus secretion in a type 2, IL13-dependent immune disease process and thereby provide a novel therapeutic strategy for attenuating airway obstruction in hypersecretory inflammatory diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis lung disease. Taken together, these observations suggest that the regulation of autophagy by Th2 cytokines is cell-context dependent.

  16. Orexin A induces autophagy in HCT-116 human colon cancer cells through the ERK signaling pathway.

    Science.gov (United States)

    Wen, Jing; Zhao, Yuyan; Guo, Lei

    2016-01-01

    Orexins are a class of peptides which have a potent influence on a broad variety of cancer cells. Autophagy is closely associated with tumors; however, its function is not yet completely understood. In this study, we aimed to determine whether orexin A induces autophagy in HCT‑116 human colon cancer cells and to elucidate the molecular mechanisms involved. For this purpose, HCT‑116 cells were treated with orexin A, and cell viability was then measured by MTT assay, and apoptosis was determined by flow cytometry. The expression levels of autophagy‑related proteins were measured by western blot analysis. Quantitative analysis of autophagy following acridine orange (AO) staining was performed using fluorescence microscopy, and cellular morphology was observed under a transmission electron microscope. In addition, the HCT‑116 cells were treated with the extracellular signal‑regulated kinase (ERK) inhibitor, U0126, or the autophagy inhibitor, chloroquine, in combination with orexin A in order to examine the activation of ERK. We found that orexin A significantly inhibited the viability of the HCT‑116 cells. Both autophagy and apoptosis were activated during the orexin A‑induced death of HCT‑116 cells. When the HCT‑116 cells were treated with orexin A for 24 h, an accumulation of punctate microtubule-associated protein-1 light chain 3 (LC3) and an increase in LC3‑Ⅱ protein levels were also detected, indicating the activation of autophagy. Moreover, orexin A upregulated ERK phosphorylation; however, U0126 or chloroquine abrogated ERK phosphorylation and decreased autophagy, compared to treatment with orexin A alone. Therefore, our findings demonstratedm that orexin A induced autophagy through the ERK pathway in HCT‑116 human colon cancer cells. The inhibition of autophagy may thus prove to be an effective strategy for enhancing the antitumor potential of orexin A as a treatment for colon cancer.

  17. The role of STAT3 in autophagy.

    Science.gov (United States)

    You, Liangkun; Wang, Zhanggui; Li, Hongsen; Shou, Jiawei; Jing, Zhao; Xie, Jiansheng; Sui, Xinbing; Pan, Hongming; Han, Weidong

    2015-01-01

    Autophagy is an evolutionarily conserved process in eukaryotes that eliminates harmful components and maintains cellular homeostasis in response to a series of extracellular insults. However, these insults may trigger the downstream signaling of another prominent stress responsive pathway, the STAT3 signaling pathway, which has been implicated in multiple aspects of the autophagic process. Recent reports further indicate that different subcellular localization patterns of STAT3 affect autophagy in various ways. For example, nuclear STAT3 fine-tunes autophagy via the transcriptional regulation of several autophagy-related genes such as BCL2 family members, BECN1, PIK3C3, CTSB, CTSL, PIK3R1, HIF1A, BNIP3, and microRNAs with targets of autophagy modulators. Cytoplasmic STAT3 constitutively inhibits autophagy by sequestering EIF2AK2 as well as by interacting with other autophagy-related signaling molecules such as FOXO1 and FOXO3. Additionally, the mitochondrial translocation of STAT3 suppresses autophagy induced by oxidative stress and may effectively preserve mitochondria from being degraded by mitophagy. Understanding the role of STAT3 signaling in the regulation of autophagy may provide insight into the classic autophagy model and also into cancer therapy, especially for the emerging targeted therapy, because a series of targeted agents execute antitumor activities via blocking STAT3 signaling, which inevitably affects the autophagy pathway. Here, we review several of the representative studies and the current understanding in this particular field.

  18. Estimating Glomerular Filtration Rate in Older People

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    Sabrina Garasto

    2014-01-01

    Full Text Available We aimed at reviewing age-related changes in kidney structure and function, methods for estimating kidney function, and impact of reduced kidney function on geriatric outcomes, as well as the reliability and applicability of equations for estimating glomerular filtration rate (eGFR in older patients. CKD is associated with different comorbidities and adverse outcomes such as disability and premature death in older populations. Creatinine clearance and other methods for estimating kidney function are not easy to apply in older subjects. Thus, an accurate and reliable method for calculating eGFR would be highly desirable for early detection and management of CKD in this vulnerable population. Equations based on serum creatinine, age, race, and gender have been widely used. However, these equations have their own limitations, and no equation seems better than the other ones in older people. New equations specifically developed for use in older populations, especially those based on serum cystatin C, hold promises. However, further studies are needed to definitely accept them as the reference method to estimate kidney function in older patients in the clinical setting.

  19. Transcriptional and epigenetic regulation of autophagy in aging.

    Science.gov (United States)

    Lapierre, Louis R; Kumsta, Caroline; Sandri, Marco; Ballabio, Andrea; Hansen, Malene

    2015-01-01

    Macroautophagy is a major intracellular degradation process recognized as playing a central role in cell survival and longevity. This multistep process is extensively regulated at several levels, including post-translationally through the action of conserved longevity factors such as the nutrient sensor TOR. More recently, transcriptional regulation of autophagy genes has emerged as an important mechanism for ensuring the somatic maintenance and homeostasis necessary for a long life span. Autophagy is increased in many long-lived model organisms and contributes significantly to their longevity. In turn, conserved transcription factors, particularly the helix-loop-helix transcription factor TFEB and the forkhead transcription factor FOXO, control the expression of many autophagy-related genes and are important for life-span extension. In this review, we discuss recent progress in understanding the contribution of these transcription factors to macroautophagy regulation in the context of aging. We also review current research on epigenetic changes, such as histone modification by the deacetylase SIRT1, that influence autophagy-related gene expression and additionally affect aging. Understanding the molecular regulation of macroautophagy in relation to aging may offer new avenues for the treatment of age-related diseases.

  20. The symphony of autophagy and calcium signaling.

    Science.gov (United States)

    Yao, Zhiyuan; Klionsky, Daniel J

    2015-01-01

    Posttranslational regulation of macroautophagy (hereafter autophagy), including phosphorylating and dephosphorylating components of the autophagy-related (Atg) core machinery and the corresponding upstream transcriptional factors, is important for the precise modulation of autophagy levels. Several kinases that are involved in phosphorylating autophagy-related proteins have been identified in both yeast and mammalian cells. However, there has been much less research published with regard to the identification of the complementary phosphatases that function in autophagy. A recent study identified PPP3/calcineurin, a calcium-dependent phosphatase, as a regulator of autophagy, and demonstrated that one of the key targets of PPP3/calcineurin is TFEB, a master transcriptional factor that controls autophagy and lysosomal function in mammalian cells.

  1. Autophagy: An Exposing Therapeutic Target in Atherosclerosis.

    Science.gov (United States)

    Luo, Yun; Lu, Shan; Zhou, Ping; Ai, Qi-Di; Sun, Gui-Bo; Sun, Xiao-Bo

    2016-03-01

    Autophagy is an evolutionarily conserved catabolic process whereby the cytoplasmic contents of a cell are sequestered within autophagosomes through a lysosome-dependent pathway. Increasing evidence shows that this process is of great importance in a wide range of diseases, including atherosclerosis (AS). Autophagy can be modulated in advanced AS plaques by cytokines, reactive lipids, lipopolysaccharides, advanced glycation end products, and microRNAs. Autophagy exerts both protective and detrimental functions in vascular disorders. However, despite an increasing interest in autophagy, it remains an underestimated and overlooked phenomenon in AS. Therefore, the precise role of autophagy and its relationship with apoptosis need to be described. This review highlights recent findings on the autophagy activities and signaling pathways in endothelial cells, macrophages, and smooth muscle cells that are accompanied by apoptosis in AS. We conclude with recent studies on autophagy modulation as a new therapeutic approach to treat AS.

  2. Modulation of pathogen recognition by autophagy

    Directory of Open Access Journals (Sweden)

    Ji Eun eOh

    2012-03-01

    Full Text Available Autophagy is an ancient biological process for maintaining cellular homeostasis by degradation of long-lived cytosolic proteins and organelles. Recent studies demonstrated that autophagy is availed by immune cells to regulate innate immunity. On the one hand, cells exert direct effector function by degrading intracellular pathogens; on the other hand, autophagy modulates pathogen recognition and downstream signaling for innate immune responses. Pathogen recognition via pattern recognition receptors induces autophagy. The function of phagocytic cells is enhanced by recruitment of autophagy-related proteins. Moreover, autophagy acts as a delivery system for viral replication complexes to migrate to the endosomal compartments where virus sensing occurs. In another case, key molecules of the autophagic pathway have been found to negatively regulate immune signaling, thus preventing aberrant activation of cytokine production and consequent immune responses. In this review, we focus on the recent advances in the role of autophagy in pathogen recognition and modulation of innate immune responses.

  3. Mechanism of reduced glomerular filtration rate in chronic malnutrition.

    Science.gov (United States)

    Ichikawa, I; Purkerson, M L; Klahr, S; Troy, J L; Martinez-Maldonado, M; Brenner, B M

    1980-05-01

    To determine the physiological basis for the low glomerular filtration rate in chronic malnutrition, micropuncture studies were performed in Munich-Wistar rats chronically pair-fed isocaloric diets of either low (group 1, nine rats) or high protein content (group 2, nine rats). Despite the absence of hypoalbuminemia, average values for single nephron and total kidney glomerular filtration rate were nearly 35% lower in group 1 than in group 2. Mean values for glomerular capillary and Bowman's space hydraulic pressures were essentially identical in the two groups, thereby excluding glomerular transcapillary hydraulic pressure difference as the cause for the low filtration rates in group 1 animals. On the other hand, average glomerular capillary plasma flow rate and glomerular capillary ultrafiltration coefficient were significantly lower (by approximately 25 and approximately 50%, respectively) in group 1 than in group 2. The fall in glomerular capillary plasma flow rate was the consequence of increased afferent and efferent arteriolar resistances. Plasma and erythrocyte volumes were found to be equal in five additional pairs of group 1 and group 2 rats. Thus, the substantial alterations in the ultrafiltration coefficient, glomerular capillary plasma flow rate, and renal arteriolar resistances responsible for the low filtration rate in group 1 animals were not merely a consequence of decreased circulating blood or plasma volumes. Mean values for glomerular cross sectional area were significantly lower in group 1 than in group 2 despite similar values for kidney weight in the two groups. This reduction in glomerular cross sectional area in group 1 rats is presumed to reflect a decrease in effective filtration surface area and therefore likely accounts, at least in part, for the decline in ultrafiltration coefficient observed in this group.Finally, since the daily caloric intake of group 2 animals was restricted because of pair feeding requirements tied to the group 1

  4. Mitochondrial damage contributes to Pseudomonas aeruginosa activation of the inflammasome and is downregulated by autophagy.

    Science.gov (United States)

    Jabir, Majid Sakhi; Hopkins, Lee; Ritchie, Neil D; Ullah, Ihsan; Bayes, Hannah K; Li, Dong; Tourlomousis, Panagiotis; Lupton, Alison; Puleston, Daniel; Simon, Anna Katharina; Bryant, Clare; Evans, Thomas J

    2015-01-01

    The nucleotide-binding domain, leucine-rich repeat containing family caspase recruitment domain containing 4 (NLRC4) inflammasome can be activated by pathogenic bacteria via products translocated through the microbial type III secretion apparatus (T3SS). Recent work has shown that activation of the NLRP3 inflammasome is downregulated by autophagy, but the influence of autophagy on NLRC4 activation is unclear. We set out to determine how autophagy might influence this process, using the bacterium Pseudomonas aeruginosa, which activates the NLRC4 inflammasome via its T3SS. Infection resulted in T3SS-dependent mitochondrial damage with increased production of reactive oxygen intermediates and release of mitochondrial DNA. Inhibiting mitochondrial reactive oxygen release or degrading intracellular mitochondrial DNA abrogated NLRC4 inflammasome activation. Moreover, macrophages lacking mitochondria failed to activate NLRC4 following infection. Removal of damaged mitochondria by autophagy significantly attenuated NLRC4 inflammasome activation. Mitochondrial DNA bound specifically to NLRC4 immunoprecipitates and transfection of mitochondrial DNA directly activated the NLRC4 inflammasome; oxidation of the DNA enhanced this effect. Manipulation of autophagy altered the degree of inflammasome activation and inflammation in an in vivo model of P. aeruginosa infection. Our results reveal a novel mechanism contributing to NLRC4 activation by P. aeruginosa via mitochondrial damage and release of mitochondrial DNA triggered by the bacterial T3SS that is downregulated by autophagy.

  5. Phlorizin Prevents Glomerular Hyperfiltration but not Hypertrophy in Diabetic Rats

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    Slava Malatiali

    2008-01-01

    Full Text Available The relationships of renal and glomerular hypertrophies to development of hyperfiltration and proteinuria early in streptozotocin-induced diabetes were explored. Control, diabetic, phlorizin-treated controls, and diabetic male Fischer rats were used. Phlorizin (an Na+-glucose cotransport inhibitor was given at a dose sufficient to normalize blood glucose. Inulin clearance (Cinulin and protein excretion rate (PER were measured. For morphometry, kidney sections were stained with periodic acid Schiff. At one week, diabetes PER increased 2.8-folds (P<.001, Cinulin increased 80% (P<.01. Kidney wet and dry weights increased 10%–12% (P<.05, and glomerular tuft area increased 9.3% (P<.001. Phlorizin prevented proteinuria, hyperfiltration, and kidney hypertrophy, but not glomerular hypertrophy. Thus, hyperfiltration, proteinuria, and whole kidney hypertrophy were related to hyperglycemia but not to glomerular growth. Diabetic glomerular hypertrophy constitutes an early event in the progression of glomerular pathology which occurs in the absence of mesangial expansion and persists even after changes in protein excretion and GFR are reversed through glycemic control.

  6. Hemodinâmica glomerular renal no roedor Calomys callosus

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    Mirian A. Boim

    1989-03-01

    Full Text Available A função renal do roedor Calomys callosus, envolvido no ciclo de transmissão de diversos agentes patogênicos para o homem foi avaliada no animal intacto, através da técnica de depuração e micropunção renal. Os resultados mostraram que este roedor apresenta níveis pressóricos, hematócrito e proteinas plasmáticas semelhantes aos dos ratos submetidos ao mesmo procedimento experimental. Os pesos corporal e renal, bem como a filtração glomerular global e por nefro assemelham-se aos do camundongo. Surpreendentemente estes roedores apresentaram significante número de glomérulos superficiais por rim, permitindo a avaliação da hemodinàmica glomerular. Apesar da pressão arterial semelhante à dos ratos Munich-Wistar (MW, a pressão hidráulica intraglomerular no Calomys callosus foi inferior. Esta redução foi conseqüente à menor resistência pós-glomerular quando comparada à dos ratos MW. O fluxo plasmático glomerular atingiu valor bastante elevado em relação à filtração glomerular por nefro, fato que não só compensaria a reduzida pressão intraglomerular, como também seria suficiente para elevar a filtração (por g/rim a níveis superiores neste roedor, pois o coeficiente de ultrafiltração glomerular (Kj foi semelhante ao do rato MW. O presente trabalho sugere que apesar das dificuldades técnicas que este animal impõe devido ao seu reduzido tamanho, o estudo da função renal global bem como da hemodinàmica glomerular é factível, podendo portanto ser utilizado como modelo para estudo da função renal em doenças tropicais.Renal function was characterized in Calomys callosus, a rodent which can participate in the transmission of several human diseases. The results showed that the pressures levels, hematocrit and plasmatic proteins were similar to rats submitted to the same experimental maneuvers. The corporal and renal weights, whole and single nephron glomerular filtration rates were similar to the mouse

  7. Obesity in kidney transplant recipients: association with decline in glomerular filtration rate.

    Science.gov (United States)

    Moreira, Thaís Rodrigues; Bassani, Tayron; de Souza, Gizele; Manfro, Roberto Ceratti; Gonçalves, Luiz Felipe Santos

    2013-10-01

    In this study we aimed to evaluate the influence of obesity in kidney and patient survival and graft function. Retrospective cohort study of kidney transplant recipients performed between 2001 and 2009. The body mass index was calculated at time of transplantation, one and five years after. The main outcomes studied were incidence of delayed graft function, new onset diabetes after transplantation, patient and graft survival, and glomerular filtration rate. The prevalence of obesity and overweight patients were 10.7% and 26.8% respectively, with an increase to 16.9% and 32.5% one year after transplantation. Underweight and obese recipients presented a higher incidence of early graft loss. The incidence of new onset diabetes after transplantation was significantly higher at one and five years in overweight or obese recipients at baseline. Overweight and obese recipients presented significantly lower estimated glomerular filtration rate at five years posttransplantation (p = 0.002). In the Kaplan-Meier analyses no statistically significant differences in patients or grafts survivals were observed. Obese patients have a higher rate of early graft failure and a higher new onset diabetes after transplantation incidence. Also, the finding of decreased glomerular filtration rate is worrisome and perhaps longer follow-up will reveal more graft failures and patients deaths in the group of obese recipients.

  8. Ordered bulk degradation via autophagy

    DEFF Research Database (Denmark)

    Dengjel, Jörn; Kristensen, Anders Riis; Andersen, Jens S

    2008-01-01

    at proteasomal and lysosomal degradation ample cross-talk between the two degradation pathways became evident. Degradation via autophagy appeared to be ordered and regulated at the protein complex/organelle level. This raises several important questions such as: can macroautophagy itself be specific and what...

  9. Sucrose induces vesicle accumulation and autophagy.

    Science.gov (United States)

    Higuchi, Takahiro; Nishikawa, Jun; Inoue, Hiroko

    2015-04-01

    It has been shown that the treatment of mammalian cells with sucrose leads to vacuole accumulation associated with lysosomes and upregulation of lysosomal enzyme expression and activity. Autophagy is an evolutionarily conserved homeostatic process by which cells deliver cytoplasmic material for degradation into lysosomes, thus it is probable that sucrose affects the autophagic activity. The role of sucrose in autophagy is unknown; however, another disaccharide, trehalose has been shown to induce autophagy. In the current study, we used mouse embryonic fibroblasts to investigate whether sucrose induces autophagy and whether vesicle formation is associated with autophagy. The results showed that sucrose induces autophagy while being accumulated within the endosomes/lysosomes. These vesicles were swollen and packed within the cytoplasm. Furthermore, trehalose and the trisaccharide raffinose, which are not hydrolyzed in mammalian cells, increased the rate of vesicles accumulation and LC3-II level (a protein marker of autophagy). However, fructose and maltose did not show the same effects. The correlation between the two processes, vesicle accumulation and autophagy induction, was confirmed by treatment of cells with sucrose plus invertase, or maltose plus acarbose-the α-glucosidase inhibitor-and by sucrose deprivation. Results also showed that vesicle accumulation was not affected by autophagy inhibition. Therefore, the data suggest that sucrose-induced autophagy through accumulation of sucrose-containing vesicles is caused by the absence of hydrolysis enzymes.

  10. Feedback regulation between autophagy and PKA.

    Science.gov (United States)

    Torres-Quiroz, Francisco; Filteau, Marie; Landry, Christian R

    2015-01-01

    Protein kinase A (PKA) controls diverse cellular processes and homeostasis in eukaryotic cells. Many processes and substrates of PKA have been described and among them are direct regulators of autophagy. The mechanisms of PKA regulation and how they relate to autophagy remain to be fully understood. We constructed a reporter of PKA activity in yeast to identify genes affecting PKA regulation. The assay systematically measures relative protein-protein interactions between the regulatory and catalytic subunits of the PKA complex in a systematic set of genetic backgrounds. The candidate PKA regulators we identified span multiple processes and molecular functions (autophagy, methionine biosynthesis, TORC signaling, protein acetylation, and DNA repair), which themselves include processes regulated by PKA. These observations suggest the presence of many feedback loops acting through this key regulator. Many of the candidate regulators include genes involved in autophagy, suggesting that not only does PKA regulate autophagy but that autophagy also sends signals back to PKA.

  11. Autophagy and IL-1 family cytokines

    Directory of Open Access Journals (Sweden)

    James eHarris

    2013-04-01

    Full Text Available Autophagy is an important intracellular homeostatic mechanism for the targeting of cytosolic constituents, including organelles, for lysosomal degradation. Autophagy plays roles in numerous physiological processes, including immune cell responses to endogenous and exogenous pathogenic stimuli. Moreover, autophagy has a potentially pivotal role to play in the regulation of inflammatory responses. In particular, autophagy regulates endogenous inflammasome activators, as well as inflammasome components and pro-IL-1β. As a result, autophagy acts a key modulator of IL-1β and IL-18, as well as IL-1α, release. This review focuses specifically on the role autophagy plays in regulating the production, processing and secretion of IL-1 and IL-18 and the consequences of this important function.

  12. Autophagy and IL-1 Family Cytokines.

    Science.gov (United States)

    Harris, James

    2013-01-01

    Autophagy is an important intracellular homeostatic mechanism for the targeting of cytosolic constituents, including organelles, for lysosomal degradation. Autophagy plays roles in numerous physiological processes, including immune cell responses to endogenous and exogenous pathogenic stimuli. Moreover, autophagy has a potentially pivotal role to play in the regulation of inflammatory responses. In particular, autophagy regulates endogenous inflammasome activators, as well as inflammasome components and pro-IL-1β. As a result, autophagy acts a key modulator of IL-1β and IL-18, as well as IL-1α, release. This review focuses specifically on the role autophagy plays in regulating the production, processing, and secretion of IL-1 and IL-18 and the consequences of this important function.

  13. Feedback regulation between autophagy and PKA

    Science.gov (United States)

    Torres-Quiroz, Francisco; Filteau, Marie; Landry, Christian R

    2015-01-01

    Protein kinase A (PKA) controls diverse cellular processes and homeostasis in eukaryotic cells. Many processes and substrates of PKA have been described and among them are direct regulators of autophagy. The mechanisms of PKA regulation and how they relate to autophagy remain to be fully understood. We constructed a reporter of PKA activity in yeast to identify genes affecting PKA regulation. The assay systematically measures relative protein-protein interactions between the regulatory and catalytic subunits of the PKA complex in a systematic set of genetic backgrounds. The candidate PKA regulators we identified span multiple processes and molecular functions (autophagy, methionine biosynthesis, TORC signaling, protein acetylation, and DNA repair), which themselves include processes regulated by PKA. These observations suggest the presence of many feedback loops acting through this key regulator. Many of the candidate regulators include genes involved in autophagy, suggesting that not only does PKA regulate autophagy but that autophagy also sends signals back to PKA. PMID:26046386

  14. Molecular mechanism and regulation of autophagy

    Institute of Scientific and Technical Information of China (English)

    Ya-ping YANG; Zhong-qin LIANG; Zhen-lun GU; Zheng-hong QIN

    2005-01-01

    Autophagy is a major cellular pathway for the degradation of long-lived proteins and cytoplasmic organelles in eukaryotic cells. A large number of intracellular/extracellular stimuli, including amino acid starvation and invasion of microorganisms, are able to induce the autophagic response in cells. The discovery of the ATG genes in yeast has greatly advanced our understanding of the molecular mechanisms participating in autophagy and the genes involved in regulating the autophagic pathway. Many yeast genes have mammalian homologs,suggesting that the basic machinery for autophagy has been evolutionarily conserved along the eukaryotic phylum. The regulation of autophagy is a very complex process. Many signaling pathways, including target of rapamycin (TOR) or mammalian target of rapamycin (mTOR), phosphatidylinositol 3-kinase-I (PI3K-I)/PKB, GTPases, calcium and protein synthesis all play important roles in regulating autophagy. The molecular mechanisms and regulation of autophagy are discussed in this review.

  15. Autophagy-lysosomal pathway is involved in lipid degradation in rat liver.

    Science.gov (United States)

    Skop, V; Cahová, M; Papáčková, Z; Páleníčková, E; Daňková, H; Baranowski, M; Zabielski, P; Zdychová, J; Zídková, J; Kazdová, L

    2012-01-01

    We present data supporting the hypothesis that the lysosomal-autophagy pathway is involved in the degradation of intracellular triacylglycerols in the liver. In primary hepatocytes cultivated in the absence of exogenous fatty acids (FFA), both inhibition of autophagy flux (asparagine) or lysosomal activity (chloroquine) decreased secretion of VLDL (very low density lipoproteins) and formation of FFA oxidative products while the stimulation of autophagy by rapamycine increased some of these parameters. Effect of rapamycine was completely abolished by inactivation of lysosomes. Similarly, when autophagic activity was influenced by cultivating the hepatocytes in "starving" (amino-acid poor medium) or "fed" (serum-supplemented medium) conditions, VLDL secretion and FFA oxidation mirrored the changes in autophagy being higher in starvation and lower in fed state. Autophagy inhibition as well as lysosomal inactivation depressed FFA and DAG (diacylglycerol) formation in liver slices in vitro. In vivo, intensity of lysosomal lipid degradation depends on the formation of autophagolysosomes, i.e. structures bringing the substrate for degradation and lysosomal enzymes into contact. We demonstrated that lysosomal lipase (LAL) activity in liver autophagolysosomal fraction was up-regulated in fasting and down-regulated in fed state together with the increased translocation of LAL and LAMP2 proteins from lysosomal pool to this fraction. Changes in autophagy intensity (LC3-II/LC3-I ratio) followed a similar pattern.

  16. Gene expression profiles of autophagy-related genes in multiple sclerosis.

    Science.gov (United States)

    Igci, Mehri; Baysan, Mehmet; Yigiter, Remzi; Ulasli, Mustafa; Geyik, Sirma; Bayraktar, Recep; Bozgeyik, İbrahim; Bozgeyik, Esra; Bayram, Ali; Cakmak, Ecir Ali

    2016-08-15

    Multiple sclerosis (MS) is an imflammatory disease of central nervous system caused by genetic and environmental factors that remain largely unknown. Autophagy is the process of degradation and recycling of damaged cytoplasmic organelles, macromolecular aggregates, and long-lived proteins. Malfunction of autophagy contributes to the pathogenesis of neurological diseases, and autophagy genes may modulate the T cell survival. We aimed to examine the expression levels of autophagy-related genes. The blood samples of 95 unrelated patients (aged 17-65years, 37 male, 58 female) diagnosed as MS and 95 healthy controls were used to extract the RNA samples. After conversion to single stranded cDNA using polyT priming: the targeted genes were pre-amplified, and 96×78 (samples×primers) qRT-PCR reactions were performed for each primer pair on each sample on a 96.96 array of Fluidigm BioMark™. Compared to age- and sex-matched controls, gene expression levels of ATG16L2, ATG9A, BCL2, FAS, GAA, HGS, PIK3R1, RAB24, RGS19, ULK1, FOXO1, HTT were significantly altered (false discovery rategenes may affect protein levels, which in turn would influence the activity of autophagy, or most probably, those genes might be acting independent of autophagy and contributing to MS pathogenesis as risk factors. The indeterminate genetic causes leading to alterations in gene expressions require further analysis.

  17. Autophagy gets in on the regulatory act

    Institute of Scientific and Technical Information of China (English)

    Steven K. Backues; Daniel J. Klionsky

    2011-01-01

    Autophagy down-regulates the Wnt signal transduction pathway via targeted degradation of a key signaling protein. This may provide an explanation for autophagy's role in tumor suppression.%@@ The eukaryotic cell has at its disposal two primary methods for getting rid of unwanted proteins: the proteasome and autophagy.The proteasome is a large protein complex comprising regulatory and proteolytic subunits whose core function is the degradation of damaged or misfolded proteins.

  18. Autophagy and apoptosis: where do they meet?

    Science.gov (United States)

    Mukhopadhyay, Subhadip; Panda, Prashanta Kumar; Sinha, Niharika; Das, Durgesh Nandini; Bhutia, Sujit Kumar

    2014-04-01

    Autophagy and apoptosis are two important cellular processes with complex and intersecting protein networks; as such, they have been the subjects of intense investigation. Recent advances have elucidated the key players and their molecular circuitry. For instance, the discovery of Beclin-1's interacting partners has resulted in the identification of Bcl-2 as a central regulator of autophagy and apoptosis, which functions by interacting with both Beclin-1 and Bax/Bak respectively. When localized to the endoplasmic reticulum and mitochondria, Bcl-2 inhibits autophagy. Cellular stress causes the displacement of Bcl-2 from Beclin-1 and Bax, thereby triggering autophagy and apoptosis, respectively. The induction of autophagy or apoptosis results in disruption of complexes by BH3-only proteins and through post-translational modification. The mechanisms linking autophagy and apoptosis are not fully defined; however, recent discoveries have revealed that several apoptotic proteins (e.g., PUMA, Noxa, Nix, Bax, XIAP, and Bim) modulate autophagy. Moreover, autophagic proteins that control nucleation and elongation regulate intrinsic apoptosis through calpain- and caspase-mediated cleavage of autophagy-related proteins, which switches the cellular program from autophagy to apoptosis. Similarly, several autophagic proteins are implicated in extrinsic apoptosis. This highlights a dual cellular role for autophagy. On one hand, autophagy degrades damaged mitochondria and caspases, and on the other hand, it provides a membrane-based intracellular platform for caspase processing in the regulation of apoptosis. In this review, we highlight the crucial factors governing the crosstalk between autophagy and apoptosis and describe the mechanisms controlling cell survival and cell death.

  19. The role of autophagy in Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    Lei Zhang; Yaru Dong; Xiaoheng Xu; Zhong Xu

    2012-01-01

    Although Parkinson's disease is the most common neurodegenerative movement disorder, the mechanisms of pathogenesis remain poorly understood. Recent findings have shown that deregulation of the autophagy-lysosome pathway is involved in the pathogenesis of Parkinson's disease. This review summarizes the most recent findings and discusses the unique role of the autophagy-lysosome pathway in Parkinson's disease to highlight the possibility of Parkinson's disease treatment strategies that incorporate autophagy-lysosome pathway modulation.

  20. The dynamic nature of autophagy in cancer.

    Science.gov (United States)

    Kimmelman, Alec C

    2011-10-01

    Macroautophagy (referred to hereafter as autophagy) is a highly regulated cellular process that serves to remove damaged proteins and organelles from the cell. Autophagy contributes to an array of normal and pathological processes, and has recently emerged as a key regulator of multiple aspects of cancer biology. The role of autophagy in cancer is complex and is likely dependent on tumor type, stage, and genetic context. This complexity is illustrated by the identification of settings where autophagy acts potently to either promote or inhibit tumorigenesis. In this review, I discuss the underlying basis for these opposing functions and propose a model suggesting a dynamic role for autophagy in malignancy. Collectively, the data point to autophagy as serving as a barrier to limit tumor initiation. Once neoplastic lesions are established, it appears that adaptive changes occur that now result in positive roles for autophagy in malignant progression and in subsequent tumor maintenance. Remarkably, constitutive activation of autophagy is critical for continued growth of some tumors, serving to both reduce oxidative stress and provide key intermediates to sustain cell metabolism. Autophagy is also induced in response to cancer therapies where it can function as a survival mechanism that limits drug efficacy. These findings have inspired significant interest in applying anti-autophagy therapies as an entirely new approach to cancer treatment. It is now apparent that aberrant control of autophagy is among the key hallmarks of cancer. While much needs to be learned about the regulation and context-dependent biological functions of autophagy, it seems clear that modulation of this process will be an attractive avenue for future cancer therapeutic approaches.

  1. Podometrics as a Potential Clinical Tool for Glomerular Disease Management.

    Science.gov (United States)

    Kikuchi, Masao; Wickman, Larysa; Hodgin, Jeffrey B; Wiggins, Roger C

    2015-05-01

    Chronic kidney disease culminating in end-stage kidney disease is a major public health problem costing in excess of $40 billion per year with high morbidity and mortality. Current tools for glomerular disease monitoring lack precision and contribute to poor outcome. The podocyte depletion hypothesis describes the major mechanisms underlying the progression of glomerular diseases, which are responsible for more than 80% of cases of end-stage kidney disease. The question arises of whether this new knowledge can be used to improve outcomes and reduce costs. Podocytes have unique characteristics that make them an attractive monitoring tool. Methodologies for estimating podocyte number, size, density, glomerular volume and other parameters in routine kidney biopsies, and the rate of podocyte detachment from glomeruli into urine (podometrics) now have been developed and validated. They potentially fill important gaps in the glomerular disease monitoring toolbox. The application of these tools to glomerular disease groups shows good correlation with outcome, although data validating their use for individual decision making is not yet available. Given the urgency of the clinical problem, we argue that the time has come to focus on testing these tools for application to individualized clinical decision making toward more effective progression prevention.

  2. Involvement of Autophagy in Coronavirus Replication

    Directory of Open Access Journals (Sweden)

    Paul Britton

    2012-11-01

    Full Text Available Coronaviruses are single stranded, positive sense RNA viruses, which induce the rearrangement of cellular membranes upon infection of a host cell. This provides the virus with a platform for the assembly of viral replication complexes, improving efficiency of RNA synthesis. The membranes observed in coronavirus infected cells include double membrane vesicles. By nature of their double membrane, these vesicles resemble cellular autophagosomes, generated during the cellular autophagy pathway. In addition, coronavirus infection has been demonstrated to induce autophagy. Here we review current knowledge of coronavirus induced membrane rearrangements and the involvement of autophagy or autophagy protein microtubule associated protein 1B light chain 3 (LC3 in coronavirus replication.

  3. Regulation of cardiomyocyte autophagy by calcium.

    Science.gov (United States)

    Shaikh, Soni; Troncoso, Rodrigo; Criollo, Alfredo; Bravo-Sagua, Roberto; García, Lorena; Morselli, Eugenia; Cifuentes, Mariana; Quest, Andrew F G; Hill, Joseph A; Lavandero, Sergio

    2016-04-15

    Calcium signaling plays a crucial role in a multitude of events within the cardiomyocyte, including cell cycle control, growth, apoptosis, and autophagy. With respect to calcium-dependent regulation of autophagy, ion channels and exchangers, receptors, and intracellular mediators play fundamental roles. In this review, we discuss calcium-dependent regulation of cardiomyocyte autophagy, a lysosomal mechanism that is often cytoprotective, serving to defend against disease-related stress and nutrient insufficiency. We also highlight the importance of the subcellular distribution of calcium and related proteins, interorganelle communication, and other key signaling events that govern cardiomyocyte autophagy.

  4. Autophagy in term normal human placentas.

    Science.gov (United States)

    Signorelli, P; Avagliano, L; Virgili, E; Gagliostro, V; Doi, P; Braidotti, P; Bulfamante, G P; Ghidoni, R; Marconi, A M

    2011-06-01

    Autophagy is an inducible catabolic process that responds to environment and is essential for cell survival during stress, starvation and hypoxia. Its function in the human placenta it is not yet understood. We collected 14 placentas: 7 at vaginal delivery and 7 at elective caesarean section after uneventful term pregnancies. The presence of autophagy was assessed in different placental areas by immunoblotting, immunohistochemistry and electron microscopy. We found that autophagy is significantly higher in placentas obtained from cesarean section than in those from vaginal delivery. Moreover there is a significant inverse relationship between autophagy and umbilical arterial glucose concentration.

  5. Autophagy : Moving Benchside Promises to Patient Bedsides.

    Science.gov (United States)

    Belaid, Amine; Ndiaye, Papa Diogop; Filippakis, Harilaos; Roux, Jérémie; Röttinger, Éric; Graba, Yacine; Brest, Patrick; Hofman, Paul; Mograbi, Baharia

    2015-01-01

    Survival rates of patients with metastatic or recurrent cancers have remained virtually unchanged during the past 30 years. This fact makes the need for new therapeutic options even more urgent. An attractive option would be to target autophagy, an essential quality control process that degrades toxic aggregates, damaged organelles, and signaling proteins, and acts as a tumor suppressor pathway of tumor initiation. Conversely, other fascinating observations suggest that autophagy supports cancer progression, relapse, metastasis, dormancy and resistance to therapy. This review provides an overview of the contradictory roles that autophagy plays in cancer initiation and progression and discusses the promises and challenges of current strategies that target autophagy for cancer therapy.

  6. Autophagy and the nutritional signaling pathway

    Directory of Open Access Journals (Sweden)

    Long HE,Shabnam ESLAMFAM,Xi MA,Defa LI

    2016-09-01

    Full Text Available During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and regulatory mechanisms. Autophagy is defined as an autolytic process to clear damaged cellular organelles and recycle the nutrients via lysosomic degradation. The process of autophagy responds to special conditions such as nutrient withdrawal. Once autophagy is induced, phagophores form and then elongate and curve to form autophagosomes. Autophagosomes then engulf cargo, fuse with endosomes, and finally fuse with lysosomes for maturation. During the initiation process, the ATG1/ULK1 (unc-51-like kinase 1 and VPS34 (which encodes a class III phosphatidylinositol (PtdIns 3-kinase complexes are critical in recruitment and assembly of other complexes required for autophagy. The process of autophagy is regulated by autophagy related genes (ATGs. Amino acid and energy starvation mediate autophagy by activating mTORC1 (mammalian target of rapamycin and AMP-activated protein kinase (AMPK. AMPK is the energy status sensor, the core nutrient signaling component and the metabolic kinase of cells. This review mainly focuses on the mechanism of autophagy regulated by nutrient signaling especially for the two important complexes, ULK1 and VPS34.

  7. Modulating autophagy: a strategy for cancer therapy

    Institute of Scientific and Technical Information of China (English)

    Jun-Lin Li; Shao-Liang Han; Xia Fan

    2011-01-01

    Autophagy is a process in which long-lived proteins,damaged cell organelles,and other cellular particles are sequestered and degraded.This process is important for maintaining the cellular microenvironment when the cell is under stress.Many studies have shown that autophagy plays a complex role in human diseases,especially in cancer,where it is known to have paradoxical effects.Namely,autophagy provides the energy for metabolism and tumor growth and leads to cell death that promotes tumor suppression.The link between autophagy and cancer is also evident in that some of the genes that regulate carcinogenesis,oncogenes and tumor suppressor genes,participate in or impact the autophagy process.Therefore,modulating autophagy will be a valuable topic for cancer therapy.Many studies have shown that autophagy can inhibit the tumor growth when autophagy modulators are combined with radiotherapy and/or chemotherapy.These findings suggest that autophagy may be a potent target for cancer therapy.

  8. Advanced Glycation End Products (AGE) Potently Induce Autophagy through Activation of RAF Protein Kinase and Nuclear Factor κB (NF-κB).

    Science.gov (United States)

    Verma, Neeharika; Manna, Sunil K

    2016-01-15

    Advanced glycation end products (AGE) accumulate in diabetic patients and aging people because of high amounts of three- or four-carbon sugars derived from glucose, thereby causing multiple consequences, including inflammation, apoptosis, obesity, and age-related disorders. It is important to understand the mechanism of AGE-mediated signaling leading to the activation of autophagy (self-eating) that might result in obesity. We detected AGE as one of the potent inducers of autophagy compared with doxorubicin and TNF. AGE-mediated autophagy is inhibited by suppression of PI3K and potentiated by the autophagosome maturation blocker bafilomycin. It increases autophagy in different cell types, and that correlates with the expression of its receptor, receptor for AGE. LC3B, the marker for autophagosomes, is shown to increase upon AGE stimulation. AGE-mediated autophagy is partially suppressed by inhibitor of NF-κB, PKC, or ERK alone and significantly in combination. AGE increases sterol regulatory element binding protein activity, which leads to an increase in lipogenesis. Although AGE-mediated lipogenesis is affected by autophagy inhibitors, AGE-mediated autophagy is not influenced by lipogenesis inhibitors, suggesting that the turnover of lipid droplets overcomes the autophagic clearance. For the first time, we provide data showing that AGE induces several cell signaling cascades, like NF-κB, PKC, ERK, and MAPK, that are involved in autophagy and simultaneously help with the accumulation of lipid droplets that are not cleared effectively by autophagy, therefore causing obesity.

  9. Podocyte Number in Children and Adults: Associations with Glomerular Size and Numbers of Other Glomerular Resident Cells.

    Science.gov (United States)

    Puelles, Victor G; Douglas-Denton, Rebecca N; Cullen-McEwen, Luise A; Li, Jinhua; Hughson, Michael D; Hoy, Wendy E; Kerr, Peter G; Bertram, John F

    2015-09-01

    Increases in glomerular size occur with normal body growth and in many pathologic conditions. In this study, we determined associations between glomerular size and numbers of glomerular resident cells, with a particular focus on podocytes. Kidneys from 16 male Caucasian-Americans without overt renal disease, including 4 children (≤3 years old) to define baseline values of early life and 12 adults (≥18 years old), were collected at autopsy in Jackson, Mississippi. We used a combination of immunohistochemistry, confocal microscopy, and design-based stereology to estimate individual glomerular volume (IGV) and numbers of podocytes, nonepithelial cells (NECs; tuft cells other than podocytes), and parietal epithelial cells (PECs). Podocyte density was calculated. Data are reported as medians and interquartile ranges (IQRs). Glomeruli from children were small and contained 452 podocytes (IQR=335-502), 389 NECs (IQR=265-498), and 146 PECs (IQR=111-206). Adult glomeruli contained significantly more cells than glomeruli from children, including 558 podocytes (IQR=431-746; Pnumber of podocytes in large glomeruli does not match the increase in glomerular size observed in adults, resulting in relative podocyte depletion. This may render hypertrophic glomeruli susceptible to pathology.

  10. The Beneficial Role of Retinoids in Glomerular Disease

    Directory of Open Access Journals (Sweden)

    Sandeep eMallipattu

    2015-03-01

    Full Text Available The primary etiology of CKD is a direct consequence of initial dysfunction and injury of the glomerulus, the main filtration system. Podocytes are terminally differentiated epithelial cells in the glomerulus, whose major function is the maintenance of this renal filtration barrier. Podocyte injury is implicated in many glomerular diseases including Focal Segmental Glomerular Sclerosis (FSGS and HIV-associated nephropathy (HIVAN. In many of these diseased conditions, the podocyte can either undergo dedifferentiation and proliferation, apoptosis, or cell detachment. Regardless of the initial type of injury, the podocyte ultimately loses its functional capacity to maintain the glomerular filtration barrier. Significant injury resulting in a loss of the podocytes and failure to maintain the renal filtration barrier contributes to progressive kidney disease. Consequently, therapies that prevent podocyte injury and promote their regeneration will have a major clinical impact on glomerular disease. Retinoic acid (RA, which is a derivative of vitamin A, has many cellular functions including induction of cell differentiation, regulation of apoptosis, and inhibition of inflammation and proliferation. RA is required for kidney development and is essential for cellular differentiation in the setting of podocyte injury. The mechanism by which RA directs its beneficial effects is multifactorial, ranging from its anti-inflammatory and anti-fibrotic effects to a direct effect of upregulating podocyte differentiation markers in the podocyte. The focus of this review is to provide an overview of RA in kidney development and glomerular disease. We also highlight the key mechanism(s by which RA restores podocyte differentiation markers and ameliorates glomerular disease.

  11. Choline Uptake by Glomerular Synapses Isolated from Bovine Cerebellar Vermis.

    Science.gov (United States)

    1986-01-01

    28 034 UNCLASSIFIED -7t. holing uptake by glomerular aynapaea isolated from bovine cerebellar venni - . 1) N1 IrRRIAN.E L NfISINndwr EtIIOMAS86 .t...w. -%FAt~Jr~a~etn 0,oAAM TX78215-5301 IL’SAJ) A-xpid ( kaolin 22nd. 19W5) hh.lhoac-anln uplake -ainalnnn 177 DIOMIDICAL DmIVIIN,~ F-5’. . Brain...Research. 366 (1986) 401-404 401 Elsevier BRE 21387 Choline uptake by glomerular synapses isolated from bovine cerebellar vermis D.M. TERRIAN, E.L

  12. Coffee induces autophagy in vivo

    Science.gov (United States)

    Pietrocola, Federico; Malik, Shoaib Ahmad; Mariño, Guillermo; Vacchelli, Erika; Senovilla, Laura; Chaba, Kariman; Niso-Santano, Mireia; Maiuri, Maria Chiara; Madeo, Frank; Kroemer, Guido

    2014-01-01

    Epidemiological studies and clinical trials revealed that chronic consumption coffee is associated with the inhibition of several metabolic diseases as well as reduction in overall and cause-specific mortality. We show that both natural and decaffeinated brands of coffee similarly rapidly trigger autophagy in mice. One to 4 h after coffee consumption, we observed an increase in autophagic flux in all investigated organs (liver, muscle, heart) in vivo, as indicated by the increased lipidation of LC3B and the reduction of the abundance of the autophagic substrate sequestosome 1 (p62/SQSTM1). These changes were accompanied by the inhibition of the enzymatic activity of mammalian target of rapamycin complex 1 (mTORC1), leading to the reduced phosphorylation of p70S6K, as well as by the global deacetylation of cellular proteins detectable by immunoblot. Immunohistochemical analyses of transgenic mice expressing a GFP–LC3B fusion protein confirmed the coffee-induced relocation of LC3B to autophagosomes, as well as general protein deacetylation. Altogether, these results indicate that coffee triggers 2 phenomena that are also induced by nutrient depletion, namely a reduction of protein acetylation coupled to an increase in autophagy. We speculate that polyphenols contained in coffee promote health by stimulating autophagy. PMID:24769862

  13. Coffee induces autophagy in vivo.

    Science.gov (United States)

    Pietrocola, Federico; Malik, Shoaib Ahmad; Mariño, Guillermo; Vacchelli, Erika; Senovilla, Laura; Chaba, Kariman; Niso-Santano, Mireia; Maiuri, Maria Chiara; Madeo, Frank; Kroemer, Guido

    2014-01-01

    Epidemiological studies and clinical trials revealed that chronic consumption coffee is associated with the inhibition of several metabolic diseases as well as reduction in overall and cause-specific mortality. We show that both natural and decaffeinated brands of coffee similarly rapidly trigger autophagy in mice. One to 4 h after coffee consumption, we observed an increase in autophagic flux in all investigated organs (liver, muscle, heart) in vivo, as indicated by the increased lipidation of LC3B and the reduction of the abundance of the autophagic substrate sequestosome 1 (p62/SQSTM1). These changes were accompanied by the inhibition of the enzymatic activity of mammalian target of rapamycin complex 1 (mTORC1), leading to the reduced phosphorylation of p70(S6K), as well as by the global deacetylation of cellular proteins detectable by immunoblot. Immunohistochemical analyses of transgenic mice expressing a GFP-LC3B fusion protein confirmed the coffee-induced relocation of LC3B to autophagosomes, as well as general protein deacetylation. Altogether, these results indicate that coffee triggers 2 phenomena that are also induced by nutrient depletion, namely a reduction of protein acetylation coupled to an increase in autophagy. We speculate that polyphenols contained in coffee promote health by stimulating autophagy.

  14. Autophagy selectivity through receptor clustering

    Science.gov (United States)

    Rutenberg, Andrew; Brown, Aidan

    Substrate selectivity in autophagy requires an all-or-none cellular response. We focus on peroxisomes, for which autophagy receptor proteins NBR1 and p62 are well characterized. Using computational models, we explore the hypothesis that physical clustering of autophagy receptor proteins on the peroxisome surface provides an appropriate all-or-none response. We find that larger peroxisomes nucleate NBR1 clusters first, and lose them due to competitive coarsening last, resulting in significant size-selectivity. We then consider a secondary hypothesis that p62 inhibits NBR1 cluster formation. We find that p62 inhibition enhances size-selectivity enough that, even if there is no change of the pexophagy rate, the volume of remaining peroxisomes can significantly decrease. We find that enhanced ubiquitin levels suppress size-selectivity, and that this effect is more pronounced for individual peroxisomes. Sufficient ubiquitin allows receptor clusters to form on even the smallest peroxisomes. We conclude that NBR1 cluster formation provides a viable physical mechanism for all-or-none substrate selectivity in pexophagy. We predict that cluster formation is associated with significant size-selectivity. Now at Simon Fraser University.

  15. Characterization of the autophagy marker protein Atg8 reveals atypical features of autophagy in Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Rahul Navale

    Full Text Available Conventional autophagy is a lysosome-dependent degradation process that has crucial homeostatic and regulatory functions in eukaryotic organisms. As malaria parasites must dispose a number of self and host cellular contents, we investigated if autophagy in malaria parasites is similar to the conventional autophagy. Genome wide analysis revealed a partial autophagy repertoire in Plasmodium, as homologs for only 15 of the 33 yeast autophagy proteins could be identified, including the autophagy marker Atg8. To gain insights into autophagy in malaria parasites, we investigated Plasmodium falciparum Atg8 (PfAtg8 employing techniques and conditions that are routinely used to study autophagy. Atg8 was similarly expressed and showed punctate localization throughout the parasite in both asexual and sexual stages; it was exclusively found in the pellet fraction as an integral membrane protein, which is in contrast to the yeast or mammalian Atg8 that is distributed among cytosolic and membrane fractions, and suggests for a constitutive autophagy. Starvation, the best known autophagy inducer, decreased PfAtg8 level by almost 3-fold compared to the normally growing parasites. Neither the Atg8-associated puncta nor the Atg8 expression level was significantly altered by treatment of parasites with routinely used autophagy inhibitors (cysteine (E64 and aspartic (pepstatin protease inhibitors, the kinase inhibitor 3-methyladenine, and the lysosomotropic agent chloroquine, indicating an atypical feature of autophagy. Furthermore, prolonged inhibition of the major food vacuole protease activity by E64 and pepstatin did not cause accumulation of the Atg8-associated puncta in the food vacuole, suggesting that autophagy is primarily not meant for degradative function in malaria parasites. Atg8 showed partial colocalization with the apicoplast; doxycycline treatment, which disrupts apicoplast, did not affect Atg8 localization, suggesting a role, but not exclusive, in

  16. Autophagy-deficiency in hepatic progenitor cells leads to the defects of stemness and enhances susceptibility to neoplastic transformation.

    Science.gov (United States)

    Xue, Feng; Hu, Lei; Ge, Ruiliang; Yang, Lixue; Liu, Kai; Li, Yunyun; Sun, Yanfu; Wang, Kui

    2016-02-01

    Autophagy is a highly conserved and lysosome-dependent degradation process which assists in cell survival and tissue homeostasis. Although previous reports have shown that deletion of the essential autophagy gene disturbs stem cell maintenance in some cell types such as hematopoietic and neural cells, it remains unclear how autophagy-deficiency influences hepatic progenitor cells (HPCs). Here we report that Atg5-deficiency in HPCs delays HPC-mediated rat liver regeneration in vivo. In vitro researches further demonstrate that loss of autophagy decreases the abilities of colony and spheroid formations, and disrupts the induction of hepatic differentiation in HPCs. Meanwhile, autophagy-deficiency increases the accumulations of damaged mitochondria and mitochondrial reactive oxygen species (mtROS) and suppresses homologous recombination (HR) pathway of DNA damage repair in HPCs. Moreover, in both diethylnitrosamine (DEN) and CCl4 models, autophagy-deficiency accelerates neoplastic transformation of HPCs. In conclusion, these findings demonstrate that autophagy contributes to stemness maintenance and reduces susceptibility to neoplastic transformation in HPCs.

  17. Keeping autophagy in cheCK1

    Science.gov (United States)

    Cheong, Jit Kong; Virshup, David M.

    2016-01-01

    Abstract Mutant RAS-driven cancer cells cope with proliferative stress by increasing basal autophagy to maintain protein/organelle and energy homeostasis. We recently demonstrated that casein kinase 1 alpha (CK1α), a therapeutically tractable enzyme, is critical for fine-tuning the transcriptional regulation of mutant RAS-induced autophagy and the development of mutant RAS-driven cancers. PMID:27314070

  18. Autophagy- An emerging target for melanoma therapy

    Science.gov (United States)

    Ndoye, Abibatou; Weeraratna, Ashani T.

    2016-01-01

    Melanoma accounts for only 5% of all cancers but is the leading cause of skin cancer death due to its high metastatic potential. Patients with metastatic melanoma have a 10-year survival rate of less than 10%. While the clinical landscape for melanoma is evolving rapidly, lack of response to therapies, as well as resistance to therapy remain critical obstacles for treatment of this disease. In recent years, a myriad of therapy resistance mechanisms have been unravelled, one of which is autophagy, the focus of this review. In advanced stages of malignancy, melanoma cells hijack the autophagy machinery in order to alleviate drug-induced and metabolic stress in the tumor microenvironment, thereby promoting resistance to multiple therapies, tumor cell survival, and progression.  Autophagy is an essential cellular process that maintains cellular homeostasis through the recycling of intracellular constituents. Early studies on the role of autophagy in cancer generated controversy as to whether autophagy was pro- or anti-tumorigenic. Currently, there is a consensus that autophagy is tumor-suppressive in the early stages of cancer and tumor-promoting in established tumors.  This review aims to highlight current understandings on the role of autophagy in melanoma malignancy, and specifically therapy resistance; as well as to evaluate recent strategies for therapeutic autophagy modulation. PMID:27583134

  19. Tumor Suppression and Promotion by Autophagy

    Directory of Open Access Journals (Sweden)

    Yenniffer Ávalos

    2014-01-01

    Full Text Available Autophagy is a highly regulated catabolic process that involves lysosomal degradation of proteins and organelles, mostly mitochondria, for the maintenance of cellular homeostasis and reduction of metabolic stress. Problems in the execution of this process are linked to different pathological conditions, such as neurodegeneration, aging, and cancer. Many of the proteins that regulate autophagy are either oncogenes or tumor suppressor proteins. Specifically, tumor suppressor genes that negatively regulate mTOR, such as PTEN, AMPK, LKB1, and TSC1/2 stimulate autophagy while, conversely, oncogenes that activate mTOR, such as class I PI3K, Ras, Rheb, and AKT, inhibit autophagy, suggesting that autophagy is a tumor suppressor mechanism. Consistent with this hypothesis, the inhibition of autophagy promotes oxidative stress, genomic instability, and tumorigenesis. Nevertheless, autophagy also functions as a cytoprotective mechanism under stress conditions, including hypoxia and nutrient starvation, that promotes tumor growth and resistance to chemotherapy in established tumors. Here, in this brief review, we will focus the discussion on this ambiguous role of autophagy in the development and progression of cancer.

  20. Tumor suppression and promotion by autophagy.

    Science.gov (United States)

    Ávalos, Yenniffer; Canales, Jimena; Bravo-Sagua, Roberto; Criollo, Alfredo; Lavandero, Sergio; Quest, Andrew F G

    2014-01-01

    Autophagy is a highly regulated catabolic process that involves lysosomal degradation of proteins and organelles, mostly mitochondria, for the maintenance of cellular homeostasis and reduction of metabolic stress. Problems in the execution of this process are linked to different pathological conditions, such as neurodegeneration, aging, and cancer. Many of the proteins that regulate autophagy are either oncogenes or tumor suppressor proteins. Specifically, tumor suppressor genes that negatively regulate mTOR, such as PTEN, AMPK, LKB1, and TSC1/2 stimulate autophagy while, conversely, oncogenes that activate mTOR, such as class I PI3K, Ras, Rheb, and AKT, inhibit autophagy, suggesting that autophagy is a tumor suppressor mechanism. Consistent with this hypothesis, the inhibition of autophagy promotes oxidative stress, genomic instability, and tumorigenesis. Nevertheless, autophagy also functions as a cytoprotective mechanism under stress conditions, including hypoxia and nutrient starvation, that promotes tumor growth and resistance to chemotherapy in established tumors. Here, in this brief review, we will focus the discussion on this ambiguous role of autophagy in the development and progression of cancer.

  1. Regulation of autophagy by cytoplasmic p53.

    Science.gov (United States)

    Tasdemir, Ezgi; Maiuri, M Chiara; Galluzzi, Lorenzo; Vitale, Ilio; Djavaheri-Mergny, Mojgan; D'Amelio, Marcello; Criollo, Alfredo; Morselli, Eugenia; Zhu, Changlian; Harper, Francis; Nannmark, Ulf; Samara, Chrysanthi; Pinton, Paolo; Vicencio, José Miguel; Carnuccio, Rosa; Moll, Ute M; Madeo, Frank; Paterlini-Brechot, Patrizia; Rizzuto, Rosario; Szabadkai, Gyorgy; Pierron, Gérard; Blomgren, Klas; Tavernarakis, Nektarios; Codogno, Patrice; Cecconi, Francesco; Kroemer, Guido

    2008-06-01

    Multiple cellular stressors, including activation of the tumour suppressor p53, can stimulate autophagy. Here we show that deletion, depletion or inhibition of p53 can induce autophagy in human, mouse and nematode cells subjected to knockout, knockdown or pharmacological inhibition of p53. Enhanced autophagy improved the survival of p53-deficient cancer cells under conditions of hypoxia and nutrient depletion, allowing them to maintain high ATP levels. Inhibition of p53 led to autophagy in enucleated cells, and cytoplasmic, not nuclear, p53 was able to repress the enhanced autophagy of p53(-/-) cells. Many different inducers of autophagy (for example, starvation, rapamycin and toxins affecting the endoplasmic reticulum) stimulated proteasome-mediated degradation of p53 through a pathway relying on the E3 ubiquitin ligase HDM2. Inhibition of p53 degradation prevented the activation of autophagy in several cell lines, in response to several distinct stimuli. These results provide evidence of a key signalling pathway that links autophagy to the cancer-associated dysregulation of p53.

  2. Stress management by autophagy: Implications for chemoresistance.

    Science.gov (United States)

    Huang, Zhao; Zhou, Li; Chen, Zhibin; Nice, Edouard C; Huang, Canhua

    2016-07-01

    Development of chemoresistance, which limits the efficiency of anticancer agents, has long been a major problem in cancer therapy and urgently needs to be solved to improve clinical outcomes. Factors contributing to chemoresistance are various, but a key factor is the cell's capability for stress management. Autophagy, a favored survival strategy that organisms employ to get over many kinds of stress, is emerging as a crucial player in drug resistance. It has been shown that autophagy facilitates the resistance of tumor cells to anticancer agents, and abrogation of autophagy could be therapeutically beneficial in some cases, suggesting autophagy could be a promising target for cancer treatments. Thus, defining the roles of autophagy in chemoresistance, and the mechanisms involved, will be critical to enhance the efficiency of chemotherapy and develop novel anticancer strategy interventions.

  3. Emerging connections between RNA and autophagy

    DEFF Research Database (Denmark)

    Frankel, Lisa B; Lubas, Michal; Lund, Anders H

    2016-01-01

    Macroautophagy/autophagy is a key catabolic process, essential for maintaining cellular homeostasis and survival through the removal and recycling of unwanted cellular material. Emerging evidence has revealed intricate connections between the RNA and autophagy research fields. While a majority...... of studies have focused on protein, lipid and carbohydrate catabolism via autophagy, accumulating data supports the view that several types of RNA and associated ribonucleoprotein complexes are specifically recruited to phagophores (precursors to autophagosomes) and subsequently degraded in the lysosome....../vacuole. Moreover, recent studies have revealed a substantial number of novel autophagy regulators with RNA-related functions, indicating roles for RNA and associated proteins not only as cargo, but also as regulators of this process. In this review, we discuss widespread evidence of RNA catabolism via autophagy...

  4. GLOMERULAR CAPILLARY GROWTH AND CELLULAR HYPERPLASIA IN A MODEL OF FOCAL AND SEGMENTAL GLOMERULOSCLEROSIS

    Directory of Open Access Journals (Sweden)

    John F Bertram

    2011-05-01

    Full Text Available Focal and segmental glomerulosclerosis (FSGS is a chronic renal disorder characterized by segmental glomerular lesions and widespread podocyte foot process effacement. We have previously shown that glomerular enlargement (hypertrophy precedes the development of FSGS in an animal model not previously thought to involve glomerular hypertrophy. This hypertrophy involved growth of glomerular capillaries. The aim of the present study was to determine whether the capillary growth involved an increase in the number of capillaries per glomerulus, or lengthening of existing capillaries. In addition, we examined the contribution of glomerular cell hyperplasia to the hypertrophy. We found that glomerular capillary growth in this model appears to primarily involve lengthening of existing capillaries rather that sprouting of new capillaries, and that glomerular cell proliferation contributes to the glomerular hypertrophy.

  5. DETECTION OF OCCULT GLOMERULAR DYSFUNCTION IN GLUCOSE SIX PHOSPHATE DEHYDROGENASE DEFICIENCY ANEMIA

    Directory of Open Access Journals (Sweden)

    Gehan Abdel Hakeem

    2016-08-01

    G6PD deficiency anemia is associated with a variable degree of glomerular dysfunction during acute hemolytic episodes. This glomerular dysfunction can result in chronic subclinical or occult chronic kidney injury.

  6. Induction of glomerular alkaline phosphatase after challenge with lipopolysaccharide

    NARCIS (Netherlands)

    Kapojos, Jola Jovita; Poelstra, Klaas; Borghuis, Theo; van den Berg, Anke; Baelde, Hans J.; Klok, P.A; Bakker, W.W

    2003-01-01

    Alkaline phosphatase (AP) can be considered as a host defence molecule since this enzyme is able to detoxify bacterial endotoxin at physiological pH. The question emerged whether this anti-endotoxin principle is inducible in the glomerulus and if so, which glomerular cells might be involved in the e

  7. Renin Lineage Cells Repopulate the Glomerular Mesangium after Injury

    Science.gov (United States)

    Starke, Charlotte; Betz, Hannah; Hickmann, Linda; Lachmann, Peter; Neubauer, Björn; Kopp, Jeffrey B.; Sequeira-Lopez, Maria Luisa S.; Gomez, R. Ariel; Hohenstein, Bernd; Hugo, Christian P.M.

    2015-01-01

    Mesangial cell injury has a major role in many CKDs. Because renin-positive precursor cells give rise to mesangial cells during nephrogenesis, this study tested the hypothesis that the same phenomenon contributes to glomerular regeneration after murine experimental mesangial injury. Mesangiolysis was induced by administration of an anti-mesangial cell serum in combination with LPS. In enhanced green fluorescent protein–reporter mice with constitutively labeled renin lineage cells, the size of the enhanced green fluorescent protein–positive area in the glomerular tufts increased after mesangial injury. Furthermore, we generated a novel Tet-on inducible triple-transgenic LacZ reporter line that allowed selective labeling of renin cells along renal afferent arterioles of adult mice. Although no intraglomerular LacZ expression was detected in healthy mice, about two-thirds of the glomerular tufts became LacZ positive during the regenerative phase after severe mesangial injury. Intraglomerular renin descendant LacZ-expressing cells colocalized with mesangial cell markers α8-integrin and PDGF receptor-β but not with endothelial, podocyte, or parietal epithelial cell markers. In contrast with LacZ-positive cells in the afferent arterioles, LacZ-positive cells in the glomerular tuft did not express renin. These data demonstrate that extraglomerular renin lineage cells represent a major source of repopulating cells for reconstitution of the intraglomerular mesangium after injury. PMID:24904091

  8. Abnormal glomerular basement membrane in idiopathic multicentric osteolysis

    NARCIS (Netherlands)

    Bakker, SJL; Vos, GD; Verschure, PDMM; Mulder, AH; Tiebosch, TMG

    1996-01-01

    The primary cause of nephropathy in idiopathic multicentric osteolysis is as yet unknown. We report a young girl with idiopathic multicentric osteolysis and nephropathy. An abnormal glomerular basement membrane was the only abnormality found in a renal biopsy taken 2 years before the development of

  9. Influence of sulfonylureas on autophagy, apoptosis, and differentiation of the mice MC3T3-E1 cells%磺脲类药物对成骨细胞MC3T3-E1自噬、凋亡和分化功能的影响

    Institute of Scientific and Technical Information of China (English)

    张丽; 季虹; 苏华; 刘兴艳; 辛衍代; 荣海钦

    2013-01-01

    目的 探讨磺脲类药物对成骨细胞自噬、凋亡及分化功能的影响. 方法 用磺酰罗丹明B染色检测不同浓度的格列本脲(GLB)、格列齐特(GLC)和格列吡嗪(GLP)对成骨细胞存活率的影响;Western blot分析3种磺脲类药物对细胞中自噬、凋亡标志蛋白表达的变化;Hoechst染色镜下观察上述药物对细胞凋亡的影响;通过对骨钙素(OCN)和碱性磷酸酶(ALP)的测定研究药物对细胞分化功能的影响. 结果 中、高浓度的GLB、GLC和GLP使MC3T3-E1细胞存活率降低.在药物干预下,MC3T3-E1细胞自噬和凋亡标志蛋白表达增加,mTOR信号途径无明显变化.3种药物可使细胞分泌OCN和ALP的能力下降. 结论 GLB、GLC和GLP可诱导成骨细胞MC3T3-E1发生自噬和凋亡,降低成骨细胞分化功能,且可能通过mTOR-非依赖途径诱导细胞自噬.%Objective To investigate the influence of sulfonylureas on the autophagy, apoptosis, and differentiation of the MC3T3-E1 cells. Methods Sulforhodamine B Assay was carried out to determine the effect of glibenclamide, gliclazide and glipizide in different concentrations on the cell survival. Western blot analysis was done to determine the protein levels of autophagy and apoptosis markers. Hoechst staining was applied to observe the impact of the three sulfonylureas on the cell apoptosis. The osteocalcin and alkaline phosphatase were assayed to assess the influence of these drugs on the differentiation of MC3T3-E1 cells. Results The intervention with glibenclamide, gliclazide, and glipizide in high concentrations made the survival rate of MC3T3-E1 cells decreased. Under the condition of drug intervention, the expression of autophagy and apoptosis markers of MC3T3-E1 cells was enhanced, whereas no remarkable changes were detected in mTOR signaling. The three sulfonylureas weakened the secretion of osteocalcin and alkaline phosphatase of MC3T3-E1 cells. Conclusion Glbenclamide, gliclazide, and glipizide

  10. Hemodinâmica glomerular renal no roedor Calomys callosus

    Directory of Open Access Journals (Sweden)

    Mirian A. Boim

    1989-03-01

    Full Text Available A função renal do roedor Calomys callosus, envolvido no ciclo de transmissão de diversos agentes patogênicos para o homem foi avaliada no animal intacto, através da técnica de depuração e micropunção renal. Os resultados mostraram que este roedor apresenta níveis pressóricos, hematócrito e proteinas plasmáticas semelhantes aos dos ratos submetidos ao mesmo procedimento experimental. Os pesos corporal e renal, bem como a filtração glomerular global e por nefro assemelham-se aos do camundongo. Surpreendentemente estes roedores apresentaram significante número de glomérulos superficiais por rim, permitindo a avaliação da hemodinàmica glomerular. Apesar da pressão arterial semelhante à dos ratos Munich-Wistar (MW, a pressão hidráulica intraglomerular no Calomys callosus foi inferior. Esta redução foi conseqüente à menor resistência pós-glomerular quando comparada à dos ratos MW. O fluxo plasmático glomerular atingiu valor bastante elevado em relação à filtração glomerular por nefro, fato que não só compensaria a reduzida pressão intraglomerular, como também seria suficiente para elevar a filtração (por g/rim a níveis superiores neste roedor, pois o coeficiente de ultrafiltração glomerular (Kj foi semelhante ao do rato MW. O presente trabalho sugere que apesar das dificuldades técnicas que este animal impõe devido ao seu reduzido tamanho, o estudo da função renal global bem como da hemodinàmica glomerular é factível, podendo portanto ser utilizado como modelo para estudo da função renal em doenças tropicais.

  11. GLOMERULAR CAPILLARY GROWTH AND CELLULAR HYPERPLASIA IN A MODEL OF FOCAL AND SEGMENTAL GLOMERULOSCLEROSIS

    OpenAIRE

    John F Bertram; Cahill, Meroe M

    2011-01-01

    Focal and segmental glomerulosclerosis (FSGS) is a chronic renal disorder characterized by segmental glomerular lesions and widespread podocyte foot process effacement. We have previously shown that glomerular enlargement (hypertrophy) precedes the development of FSGS in an animal model not previously thought to involve glomerular hypertrophy. This hypertrophy involved growth of glomerular capillaries. The aim of the present study was to determine whether the capillary growth involved an incr...

  12. HEMA but not TEGDMA induces autophagy in human gingival fibroblasts

    Science.gov (United States)

    Teti, Gabriella; Orsini, Giovanna; Salvatore, Viviana; Focaroli, Stefano; Mazzotti, Maria C.; Ruggeri, Alessandra; Mattioli-Belmonte, Monica; Falconi, Mirella

    2015-01-01

    Polymerized resin-based materials are successfully used in restorative dentistry. Despite their growing popularity, one drawback is the release of monomers from the polymerized matrix due to an incomplete polymerization or degradation processes. Released monomers are responsible for several adverse effects in the surrounding biological tissues, inducing high levels of oxidative stress. Reactive oxygen species are important signaling molecules that regulate many signal-trasduction pathways and play critical roles in cell survival, death, and immune defenses. Reactive oxygen species were recently shown to activate autophagy as a mechanism of cell survival and cell death. Although the toxicity induced by dental resin monomers is widely studied, the cellular mechanisms underlying these phenomena are still unknown. The aim of the study was to investigate the behavior of human gingival cells exposed to 2-hydroxy-ethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) to better elucidate the mechanisms of cell survival and cell death induced by resin monomers. Primary culture of human gingival cells were exposed to 3 mmol/L of HEMA or 3 mmol/L of TEGDMA for 24, 48, and 72 h. Morphological investigations were performed by transmission electron microscopy to analyze the ultrastructure of cells exposed to the monomers. The expression of protein markers for apoptosis (caspase – 3 and PARP) and autophagy (beclin – 1 and LC3B I/II) were analyzed by western blot to investigate the influence of dental resin monomers on mechanisms underlying cell death. Results showed that HEMA treatment clearly induced autophagy followed by apoptosis while the lack of any sign of autophagy activation is observed in HGFs exposed to TEGDMA. These data indicate that cells respond to monomer-induced stress by the differential induction of adaptive mechanisms to maintain cellular homeostasis. PMID:26483703

  13. HEMA but not TEGDMA Induces Autophagy in Human Gingival Fibroblasts.

    Directory of Open Access Journals (Sweden)

    gabriella eteti

    2015-10-01

    Full Text Available Polymerized resin-based materials are successfully used in restorative dentistry. Despite their growing popularity, one drawback is the release of monomers from the polymerized matrix due to an incomplete polymerization or degradation processes. Released monomers are responsible for several adverse effects in the surrounding biological tissues, inducing high levels of oxidative stress. Reactive oxygen species are important signaling molecules that regulate many signal-trasduction pathways and play critical roles in cell survival, death, and immune defenses. Reactive oxygen species were recently shown to activate autophagy as a mechanism of cell survival and cell death. Although the toxicity induced by dental resin monomers is widely studied, the cellular mechanisms underlying these phenomena are still unknown. The aim of the study was to investigate the behavior of human gingival cells exposed to 2-hydroxy-ethyl methacrylate (HEMA and triethylene glycol dimethacrylate (TEGDMA to better elucidate the mechanisms of cell survival and cell death induced by resin monomers. Primary culture of human gingival cells were exposed to 3mmol/L of HEMA or 3mmol/L of TEGDMA for 24 h, 48h, and 72 h. Morphological investigations were performed by transmission electron microscopy to analyze the ultrastructure of cells exposed to the monomers. The expression of protein markers for apoptosis (caspase – 3 and PARP and autophagy (beclin – 1 and LC3B I/II were analyzed by western blot to investigate the influence of dental resin monomers on mechanisms underlying cell death. Results showed that HEMA treatment clearly induced autophagy followed by apoptosis while the lack of any sign of autophagy activation is observed in HGFs exposed to TEGDMA. These data indicate that cells respond to monomer-induced stress by the differential induction of adaptive mechanisms to maintain cellular homeostasis.

  14. Contribution of glomerular morphometry to the diagnosis of pediatric nephropathies

    Directory of Open Access Journals (Sweden)

    Mariana Barreto Marini

    2016-01-01

    Full Text Available Only a few studies describe histopathological changes in renal biopsies performed in pediatric patients. This study was conducted to identify an association between morphometric data in renal biopsies and renal function of these patients. Fifty-nine individuals with ages between 2 and 18 years old were selected, who were divided into six groups consisting of frequent nephropathies in children and adolescents and one control group. Proteinuria, urea, and creatinine values of the patients were recorded. Interactive image analysis software Leica QWin[®]was used for morpho- metric analysis of Bowman′s capsule, glomerular capillary tuft, and Bowman′s space area. The mean glomerular tuft area was higher in the membranous glomerulopathy group than in the podo- cytopathy group (57,101 ± 25,094 vs. 27,420 c ± 6279 µm2; P <0.05. The median of Bowman′s space area was higher in the control group than in the podocytopathy group and in the thin basement membrane/Alport syndrome group [12,210 (7676-26,945 vs. 5801 (3031-7852 µm2; P <0.01 and 12210 (7676-26,945 vs. 4183 (3797-7992 µm2; P <0.01, respectively]. There was a positive and significant correlation between Bowman′s capsule area and the levels of proteinuria, creatinine, and urea of the patients, as well as between the glomerular tuft area and the levels of proteinuria, creatinine, and urea in the patients, regardless of their nephropathy. Glomerular morphometry may contribute to the diagnosis of some glomerulopathies and the association between glomerular morphometric parameters, and laboratory data may promote a better understanding of the prognosis of these patients.

  15. The glomerular filtration rate during pregnancy : Saline infusion enhances the glomerular filtration rate in the pregnant rat

    NARCIS (Netherlands)

    Faas, MM; Schuiling, GA; Klok, PA; Valkhof, N; Bakker, WW

    1996-01-01

    The glomerular filtration rate (GFR) of pregnant rats is generally believed to exceed non-pregnant values. This notion is primarily based upon standard inulin clearances. However, the inulin clearance requires continuous infusion of inulin usually dissolved in saline. Since saline infusion per se in

  16. The influence of blood glucose level on glomerular filtration rate and its estimation equations in type 2 diabetes%血糖水平对2型糖尿病患者肾小球滤过率及其评估方程的影响

    Institute of Scientific and Technical Information of China (English)

    张萌; 黄清梅; 简小金; 方红娟; 杨金奎

    2011-01-01

    目的 探讨不同血糖水平对2型糖尿病患者肾小球滤过率(GFR)及其评估方程的影响方法 选择经同位素99mTc-DTPA测定GFR的2型糖尿病患者495例,HbA1c与99mTc-DTPA测定GFR及CG方程、MDRD方程和MCQ方程GFR估计值之间进行相关性分析;以HbA1c=8%为临界值,比较两组间各评估方程的精确性和准确性.结果:经同位素测定的GFR为(70.11±20.54)ml·min(-1)·(1.73 m2)(-1),HbA1c与同位素测定GFR及CG方程、MDRD方程和MCQ方程GFR估计值呈正相关(γ值分别为0.196、0.201、0.289和0.181,P<0.01).无论血糖水平如何,CG方程的准确性都明显高于其他两个方程.结论 近期高血糖增加同位素测定GFR和方程估算GFR的水平.虽然这些评估方程存在一些不足之处,但由于目前尚缺乏专门针对糖尿病人群的评估方程,在临床实际工作中采用CG方程来评估2型糖尿病患者的GFR不失为一个简便实用的方法.%Objective To discuss the influence of different blood glucose levels on glomerular filtration rate (GFR) and on its estimation equations in type 2 diabetes. Methods 495 type 2 diabetic patients undergoing GFR measurement using 99m Tc-DTPA were enrolled in this study. The correlations were performed between glycosylated hemoglobin (HbA1c) and 99m Tc-DTPA measured GFR and its estimations by CG, MDRD and MCQ equations. The precision and accuracy were compared among these three estimating equations under the threshold of HbA1c 8 %. Results When GFR measured using 99m Tc-DTPA was (70. 11 ± 20. 54 ) ml· min-1 · ( 1.73 m2 )-1, HbA1c was positively correlated with isotopically measured GFR and its estimations by CG, MDRD and MCQ equations (r=0. 196, 0. 201,0. 289 and 0.181, P<0. 01). CG equation was more accurate than the other equations regardless of blood glucose level. Conclusions Acute hyperglycemia increases isotopically measured GFR and its estimations. These equations all have some disadvantages in estimating GFR, but in

  17. Autophagy in human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Thien Tra

    Full Text Available Autophagy (macroautophagy is a degradative process that involves the sequestration of cytosolic material including organelles into double membrane vesicles termed autophagosomes for delivery to the lysosome. Autophagy is essential for preimplantation development of mouse embryos and cavitation of embryoid bodies. The precise roles of autophagy during early human embryonic development, remain however largely uncharacterized. Since human embryonic stem cells constitute a unique model system to study early human embryogenesis we investigated the occurrence of autophagy in human embryonic stem cells. We have, using lentiviral transduction, established multiple human embryonic stem cell lines that stably express GFP-LC3, a fluorescent marker for the autophagosome. Each cell line displays both a normal karyotype and pluripotency as indicated by the presence of cell types representative of the three germlayers in derived teratomas. GFP expression and labelling of autophagosomes is retained after differentiation. Baseline levels of autophagy detected in cultured undifferentiated hESC were increased or decreased in the presence of rapamycin and wortmannin, respectively. Interestingly, autophagy was upregulated in hESCs induced to undergo differentiation by treatment with type I TGF-beta receptor inhibitor SB431542 or removal of MEF secreted maintenance factors. In conclusion we have established hESCs capable of reporting macroautophagy and identify a novel link between autophagy and early differentiation events in hESC.

  18. Autophagy in granular corneal dystrophy type 2.

    Science.gov (United States)

    Choi, Seung-Il; Kim, Eung Kweon

    2016-03-01

    Autophagy is a lysosomal degradative process that is essential for cellular homeostasis and metabolic stress adaptation. Defective autophagy is involved in the pathogenesis of many diseases including granular corneal dystrophy type 2 (GCD2). GCD2 is an autosomal dominant disorder caused by substitution of histidine for arginine at codon 124 (R124H) in the transforming growth factor β-induced gene (TGFBI) on chromosome 5q31. Transforming growth factor β-induced protein (TGFBIp) is degraded by autophagy, but mutant-TGFBIp accumulates in autophagosomes and/or lysosomes, despite significant activation of basal autophagy, in GCD2 corneal fibroblasts. Furthermore, inhibition of autophagy induces cell death of GCD2 corneal fibroblasts through active caspase-3. As there is currently no pharmacological treatment for GCD2, development of novel therapies is required. A potential strategy for preventing cytoplasmic accumulation of mutant-TGFBIp in GCD2 corneal fibroblasts is to enhance mutant-TGFBIp degradation. This could be achieved by activation of the autophagic pathway. Here, we will consider the role and the potential therapeutic benefits of autophagy in GCD2, with focus on TGFBIp degradation, in light of the recently established role of autophagy in protein degradation.

  19. Guidelines for monitoring autophagy in Caenorhabditis elegans.

    Science.gov (United States)

    Zhang, Hong; Chang, Jessica T; Guo, Bin; Hansen, Malene; Jia, Kailiang; Kovács, Attila L; Kumsta, Caroline; Lapierre, Louis R; Legouis, Renaud; Lin, Long; Lu, Qun; Meléndez, Alicia; O'Rourke, Eyleen J; Sato, Ken; Sato, Miyuki; Wang, Xiaochen; Wu, Fan

    2015-01-01

    The cellular recycling process of autophagy has been extensively characterized with standard assays in yeast and mammalian cell lines. In multicellular organisms, numerous external and internal factors differentially affect autophagy activity in specific cell types throughout the stages of organismal ontogeny, adding complexity to the analysis of autophagy in these metazoans. Here we summarize currently available assays for monitoring the autophagic process in the nematode C. elegans. A combination of measuring levels of the lipidated Atg8 ortholog LGG-1, degradation of well-characterized autophagic substrates such as germline P granule components and the SQSTM1/p62 ortholog SQST-1, expression of autophagic genes and electron microscopy analysis of autophagic structures are presently the most informative, yet steady-state, approaches available to assess autophagy levels in C. elegans. We also review how altered autophagy activity affects a variety of biological processes in C. elegans such as L1 survival under starvation conditions, dauer formation, aging, and cell death, as well as neuronal cell specification. Taken together, C. elegans is emerging as a powerful model organism to monitor autophagy while evaluating important physiological roles for autophagy in key developmental events as well as during adulthood.

  20. Coordination of autophagy with other cellular activities

    Institute of Scientific and Technical Information of China (English)

    Yan WANG; Zheng-hong QIN

    2013-01-01

    The cell biological phenomenon of autophagy has attracted increasing attention in recent years,partly as a consequence of the discovery of key components of its cellular machinery.Autophagy plays a crucial role in a myriad of cellular functions.Autophagy has its own regulatory mechanisms,but this process is not isolated.Autophagy is coordinated with other cellular activities to maintain cell homeostasis.Autophagy is critical for a range of human physiological processes.The multifunctional roles of autophagy are explained by its ability to interact with several key components of various cell pathways.In this review,we focus on the coordination between autophagy and other physiological processes,including the ubiquitin-proteasome system (UPS),energy homeostasis,aging,programmed cell death,the immune responses,microbial invasion and inflammation.The insights gained from investigating autophagic networks should increase our understanding of their roles in human diseases and their potential as targets for therapeutic intervention.

  1. Autophagy in lung disease pathogenesis and therapeutics

    Directory of Open Access Journals (Sweden)

    Stefan W. Ryter

    2015-04-01

    Full Text Available Autophagy, a cellular pathway for the degradation of damaged organelles and proteins, has gained increasing importance in human pulmonary diseases, both as a modulator of pathogenesis and as a potential therapeutic target. In this pathway, cytosolic cargos are sequestered into autophagosomes, which are delivered to the lysosomes where they are enzymatically degraded and then recycled as metabolic precursors. Autophagy exerts an important effector function in the regulation of inflammation, and immune system functions. Selective pathways for autophagic degradation of cargoes may have variable significance in disease pathogenesis. Among these, the autophagic clearance of bacteria (xenophagy may represent a crucial host defense mechanism in the pathogenesis of sepsis and inflammatory diseases. Our recent studies indicate that the autophagic clearance of mitochondria, a potentially protective program, may aggravate the pathogenesis of chronic obstructive pulmonary disease by activating cell death programs. We report similar findings with respect to the autophagic clearance of cilia components, which can contribute to airways dysfunction in chronic lung disease. In certain diseases such as pulmonary hypertension, autophagy may confer protection by modulating proliferation and cell death. In other disorders, such as idiopathic pulmonary fibrosis and cystic fibrosis, impaired autophagy may contribute to pathogenesis. In lung cancer, autophagy has multiple consequences by limiting carcinogenesis, modulating therapeutic effectiveness, and promoting tumor cell survival. In this review we highlight the multiple functions of autophagy and its selective autophagy subtypes that may be of significance to the pathogenesis of human disease, with an emphasis on lung disease and therapeutics.

  2. Autophagy in Mycobacterium tuberculosis and HIV infections

    Directory of Open Access Journals (Sweden)

    Lucile eEspert

    2015-06-01

    Full Text Available Human Immunodeficiency Virus (HIV and Mycobacterium tuberculosis (M.tb are among the most lethal human pathogens worldwide, each being responsible for around 1.5 million deaths annually. Moreover, synergy between acquired immune deficiency syndrome (AIDS and tuberculosis (TB has turned HIV/M.tb co-infection into a major public health threat in developing countries. In the past decade, autophagy, a lysosomal catabolic process, has emerged as a major host immune defense mechanism against infectious agents like M.tb and HIV. Nevertheless, in some instances, autophagy machinery appears to be instrumental for HIV infection. Finally, there is mounting evidence that both pathogens deploy various countermeasures to thwart autophagy. This mini-review proposes an overview of the roles and regulations of autophagy in HIV and M.tb infections with an emphasis on microbial factors. We also discuss the role of autophagy manipulation in the context of HIV/M.tb co-infection. In future, a comprehensive understanding of autophagy interaction with these pathogens will be critical for development of autophagy-based prophylactic and therapeutic interventions for AIDS and TB.

  3. Autophagy: for better or for worse

    Institute of Scientific and Technical Information of China (English)

    Ellen Wirawan; Tom Vanden Berghe; Saskia Lippens; Patrizia Agostinis; Peter Vandenabeele

    2012-01-01

    Autophagy is a lysosomal degradation pathway that degrades damaged or superfluous cell components into basic biomolecules,which are then recycled back into the cytosol.In this respect,autophagy drives a flow of biomolecules in a continuous degradation-regeneration cycle.Autophagy is generally considered a pro-survival mechanism protecting cells under stress or poor nutrient conditions.Current research clearly shows that autophagy fulfills numerous functions in vital biological processes.It is implicated in development,differentiation,innate and adaptive immunity,ageing and cell death.In addition,accumulating evidence demonstrates interesting links between autophagy and several human diseases and tumor development.Therefore,autophagy seems to be an important player in the life and death of cells and organisms.Despite the mounting knowledge about autophagy,the mechanisms through which the autophagic machinery regulates these diverse processes are not entirely understood.In this review,we give a comprehensive overview of the autophagic signaling pathway,its role in general cellular processes and its connection to cell death.In addition,we present a brief overview of the possible contribution of defective autophagic signaling to disease.

  4. Intrinsically disordered regions in autophagy proteins.

    Science.gov (United States)

    Mei, Yang; Su, Minfei; Soni, Gaurav; Salem, Saeed; Colbert, Christopher L; Sinha, Sangita C

    2014-04-01

    Autophagy is an essential eukaryotic pathway required for cellular homeostasis. Numerous key autophagy effectors and regulators have been identified, but the mechanism by which they carry out their function in autophagy is not fully understood. Our rigorous bioinformatic analysis shows that the majority of key human autophagy proteins include intrinsically disordered regions (IDRs), which are sequences lacking stable secondary and tertiary structure; suggesting that IDRs play an important, yet hitherto uninvestigated, role in autophagy. Available crystal structures corroborate the absence of structure in some of these predicted IDRs. Regions of orthologs equivalent to the IDRs predicted in the human autophagy proteins are poorly conserved, indicating that these regions may have diverse functions in different homologs. We also show that IDRs predicted in human proteins contain several regions predicted to facilitate protein-protein interactions, and delineate the network of proteins that interact with each predicted IDR-containing autophagy protein, suggesting that many of these interactions may involve IDRs. Lastly, we experimentally show that a BCL2 homology 3 domain (BH3D), within the key autophagy effector BECN1 is an IDR. This BH3D undergoes a dramatic conformational change from coil to α-helix upon binding to BCL2s, with the C-terminal half of this BH3D constituting a binding motif, which serves to anchor the interaction of the BH3D to BCL2s. The information presented here will help inform future in-depth investigations of the biological role and mechanism of IDRs in autophagy proteins.

  5. Inhibition of caspase-9 aggravates acute liver injury through suppression of cytoprotective autophagy

    Science.gov (United States)

    Guo, Rui; Lin, Bin; Pan, Jing Fei; Liong, Emily C.; Xu, Ai Min; Youdim, Moussa; Fung, Man Lung; So, Kwok Fai; Tipoe, George L.

    2016-01-01

    Acute liver disease is characterized by inflammation, oxidative stress and necrosis, which can greatly influence the long term clinical outcome and lead to liver failure or cancer. Here, we initially demonstrated the beneficial role of caspase-9-dependent autophagy in acute liver injury. Treatment with caspase-9 inhibitor z-LEHD-FMK in HepG2 cells, AML12 cells and C57BL/b6N mice exacerbated CCl4-induced acute hepatocellular damage, and also down-regulated autophagy markers expression levels, indicating that caspase-9 inhibition may aggravate acute liver damage by suppressing cytoprotective autophagy. CCl4 was used as an acute liver injury inducer which caused oxidative stress and apoptosis through up-regulation of HIF-1α, as well as triggered hepatic inflammation and necroptosis via TLR4/NF-κB pathway. Caspase-9 Thr125 site was firstly phosphorylated by ERK1/2 which subsequently activated the cytoprotective autophagy process to attenuate acute CCl4 injury. Caspase-9 inhibition further aggravated hepatic necroptosis through NF-κB expression, leading to increased pro-inflammatory mediators levels, suggesting a protective role of caspase-9-dependent autophagy in the inflammatory process as well as its possibility being a new therapeutic target for the treatment of acute liver injury. PMID:27580936

  6. The dual role of autophagy under hypoxia-involvement of interaction between autophagy and apoptosis.

    Science.gov (United States)

    Li, Mengmeng; Tan, Jin; Miao, Yuyang; Lei, Ping; Zhang, Qiang

    2015-06-01

    Hypoxia is one of severe cellular stress and it is well known to be associated with a worse outcome since a lack of oxygen accelerates the induction of apoptosis. Autophagy, an important and evolutionarily conserved mechanism for maintaining cellular homeostasis, is closely related to the apoptosis caused by hypoxia. Generally autophagy blocks the induction of apoptosis and inhibits the activation of apoptosis-associated caspase which could reduce cellular injury. However, in special cases, autophagy or autophagy-relevant proteins may help to induce apoptosis, which could aggravate cell damage under hypoxia condition. In addition, the activation of apoptosis-related proteins-caspase can also degrade autophagy-related proteins, such as Atg3, Atg4, Beclin1 protein, inhibiting autophagy. Although the relationship between autophagy and apoptosis has been known for rather complex for more than a decade, the underlying regulatory mechanisms have not been clearly understood. This short review discusses and summarizes the dual role of autophagy and the interaction and molecular regulatory mechanisms between autophagy and apoptosis under hypoxia.

  7. Effect of Autophagy Over Liver Diseases

    Institute of Scientific and Technical Information of China (English)

    Dong-qian Yi; Xue-feng Yang; Duan-fang Liao; Qing Wu; Nian Fu; Yang Hu; Ting Cao

    2016-01-01

    Abstract In recent years, increasingly evidences show that autophagy plays an important role in the pathogenesis and development of liver diseases, and the relationship between them has increasingly become a focus of concern. Autophagy refers to the process through which the impaired organelles, misfolded protein, and intruding microorganisms is degraded by lysosomes to maintain stability inside cells. This article states the effect of autophagy on liver diseases (hepatic fibrosis, fatty liver, viral hepatitis, and liver cancer), which aims to provide a new direction for the treatment of liver diseases.

  8. Autophagy mitigates metabolic stress and genome damage in mammary tumorigenesis

    Science.gov (United States)

    Karantza-Wadsworth, Vassiliki; Patel, Shyam; Kravchuk, Olga; Chen, Guanghua; Mathew, Robin; Jin, Shengkan; White, Eileen

    2007-01-01

    Autophagy is a catabolic process involving self-digestion of cellular organelles during starvation as a means of cell survival; however, if it proceeds to completion, autophagy can lead to cell death. Autophagy is also a haploinsufficient tumor suppressor mechanism for mammary tumorigenesis, as the essential autophagy regulator beclin1 is monoallelically deleted in breast carcinomas. However, the mechanism by which autophagy suppresses breast cancer remains elusive. Here we show that allelic loss of beclin1 and defective autophagy sensitized mammary epithelial cells to metabolic stress and accelerated lumen formation in mammary acini. Autophagy defects also activated the DNA damage response in vitro and in mammary tumors in vivo, promoted gene amplification, and synergized with defective apoptosis to promote mammary tumorigenesis. Therefore, we propose that autophagy limits metabolic stress to protect the genome, and that defective autophagy increases DNA damage and genomic instability that ultimately facilitate breast cancer progression. PMID:17606641

  9. Oxidative stress-induced autophagy: Role in pulmonary toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Malaviya, Rama [Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854 (United States); Laskin, Jeffrey D. [Department of Environmental and Occupational Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854 (United States); Laskin, Debra L., E-mail: laskin@eohsi.rutgers.edu [Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854 (United States)

    2014-03-01

    Autophagy is an evolutionarily conserved catabolic process important in regulating the turnover of essential proteins and in elimination of damaged organelles and protein aggregates. Autophagy is observed in the lung in response to oxidative stress generated as a consequence of exposure to environmental toxicants. Whether autophagy plays role in promoting cell survival or cytotoxicity is unclear. In this article recent findings on oxidative stress-induced autophagy in the lung are reviewed; potential mechanisms initiating autophagy are also discussed. A better understanding of autophagy and its role in pulmonary toxicity may lead to the development of new strategies to treat lung injury associated with oxidative stress. - Highlights: • Exposure to pulmonary toxicants is associated with oxidative stress. • Oxidative stress is known to induce autophagy. • Autophagy is upregulated in the lung following exposure to pulmonary toxicants. • Autophagy may be protective or pathogenic.

  10. Autophagy as a Stress Response Pathway in the Immune System.

    Science.gov (United States)

    Bhattacharya, Abhisek; Eissa, N Tony

    2015-01-01

    Macroautophagy, hereafter, referred to as autophagy, has long been regarded as a housekeeping pathway involved in intracellular degradation and energy recycling. These housekeeping and homeostatic functions are especially important during cellular stress, such as periods of nutrient deprivation. However, importance of autophagy extends far beyond its degradative functions. Recent evidence shows that autophagy plays an essential role in development, organization and functions of the immune system, and defects in autophagy lead to several diseases, including cancer and autoimmunity. In the immune system, autophagy is important in regulation of the innate and adaptive immune responses. This review focuses on the roles of autophagy in the adaptive immune system. We first introduce the autophagy pathway and provide a brief description of the major molecular players involved in autophagy. We then discuss the importance of autophagy as a stress integrator mechanism and provide relevant examples of this role of autophagy in adaptive immune cells. Then we proceed to describe how autophagy regulates development, activation and functions of different adaptive immune cells. In these contexts, we mention both degradative and non-degradative roles of autophagy, and illustrate their importance. We also discuss role of autophagy in antigen presenting cells, which play critical roles in the activation of adaptive immune cells. Further, we describe how autophagy regulates functions of different adaptive immune cells during infection, inflammation and autoimmunity.

  11. Cell biology of mesangial cells: the third cell that maintains the glomerular capillary.

    Science.gov (United States)

    Kurihara, Hidetake; Sakai, Tatsuo

    2017-03-01

    The renal glomerulus consists of glomerular endothelial cells, podocytes, and mesangial cells, which cooperate with each other for glomerular filtration. We have produced monoclonal antibodies against glomerular cells in order to identify different types of glomerular cells. Among these antibodies, the E30 clone specifically recognizes the Thy1.1 molecule expressed on mesangial cells. An injection of this antibody into rats resulted in mesangial cell-specific injury within 15 min, and induced mesangial proliferative glomerulonephritis in a reproducible manner. We examined the role of mesangial cells in glomerular function using several experimental tools, including an E30-induced nephritis model, mesangial cell culture, and the deletion of specific genes. Herein, we describe the characterization of E30-induced nephritis, formation of the glomerular capillary network, mesangial matrix turnover, and intercellular signaling between glomerular cells. New molecules that are involved in a wide variety of mesangial cell functions are also introduced.

  12. Glomerular Glucocorticoid Receptors Expression and Clinicopathological Types of Childhood Nephrotic Syndrome.

    Science.gov (United States)

    Gamal, Yasser; Badawy, Ahlam; Swelam, Salwa; Tawfeek, Mostafa S K; Gad, Eman Fathalla

    2017-02-01

    Glucocorticoids are primary therapy of idiopathic nephrotic syndrome (INS). However, not all children respond to steroid therapy. We assessed glomerular glucocorticoid receptor expression in fifty-one children with INS and its relation to response to steroid therapy and to histopathological type. Clinical, laboratory and glomerular expression of glucocorticoid receptors were compared between groups with different steroid response. Glomerular glucocorticoid expression was slightly higher in controls than in minimal change early responders, which in turn was significantly higher than in minimal change late responders. There was significantly lower glomerular glucocorticoid receptor expression in steroid-resistance compared to early responders, late responders and controls. Glomerular glucocorticoid expression was significantly higher in all minimal change disease (MCD) compared to focal segmental glomerulosclerosis. In INS, response to glucocorticoid is dependent on glomerular expression of receptors and peripheral expression. Evaluation of glomerular glucocorticoid receptor expression at time of diagnosis of NS can predict response to steroid therapy.

  13. Validation of glomerular basement membrane thickness changes with aging in minimal change disease.

    Science.gov (United States)

    Sato, Shigeru; Sasaki, Yoshihiro; Adachi, Akiko; Ghazizadeh, Mohammad

    2010-01-01

    Measurement of the normal range of glomerular basement membrane (GBM) thickness by electron microscopy is required for the diagnosis of thin basement membrane disease or diabetic nephropathy; however, this measurement is influenced by aging. The aim of this study was to introduce a simple histogram plotting method for the validation of the results of the GBM thickness measurements by the accepted arithmetic mean ± SD method. We examined renal biopsy specimens obtained from 19 patients (10 males and 9 females) with minimal change disease, ranging in age from 3 to 70 years. Renal tissue samples obtained at autopsy from a male baby (3 months old) with no renal disease were also examined. For each case, GBM thicknesses at 10-15 evenly distributed points per glomerular loop were directly measured and the arithmetic mean ± SD was calculated. Subsequently, the arithmetic mean ± SD for each group of cases classified by age into 4 groups, i.e. babyhood (3 months old), childhood (3-11 years old), adulthood (12-57 years old), and old age (60-70 years old), was determined. On the other hand, a histogram of the frequency of GBM points measured against thickness was plotted to determine the distribution pattern and the range of measurements in each age group. The histogram plot showed 4 clearly divided modes for GBM thickness. Comparison of the results obtained by the 2 methods revealed a significant correlation indicating the feasibility of the histogram plotting method as a useful adjunct to validate GBM thickness measurements.

  14. The renal handling of hemoglobin. I. Glomerular filtration.

    Science.gov (United States)

    Bunn, H F; Esham, W T; Bull, R W

    1969-05-01

    The glomerular filtration of hemoglobin (alpha(2)beta(2)) was studied under conditions in which its dissociation into alphabeta dimers was experimentally altered. Rats receiving hemoglobin treated with the sulfhydryl reagent bis(N-maleimidomethyl) ether (BME) showed a much lower renal excretion and prolonged plasma survival as compared with animals injected with untreated hemoglobin. Plasma disappearance was also prolonged in dogs receiving BME hemoglobin. Gel filtration data indicated that under physiological conditions, BME hemoglobin had impaired subunit dissociation. In addition, BME hemoglobin showed a very high oxygen affinity and a decreased rate of auto-oxidation. Glomerular filtration was enhanced under conditions which favor the dissociation of hemoglobin into dimers. Cat hemoglobin, which forms subunits much more extensively than canine hemoglobin, was excreted more readily by the rat kidney. The renal uptake of (59)Fe hemoglobin injected intra-arterially into rabbits varied inversely with the concentration of the injected dose.

  15. Renin Lineage Cells Repopulate the Glomerular Mesangium after Injury

    OpenAIRE

    Starke, Charlotte; Betz, Hannah; Hickmann, Linda; Lachmann, Peter; Neubauer, Björn; Kopp, Jeffrey B.; Sequeira-Lopez, Maria Luisa S; Gomez, R. Ariel; Hohenstein, Bernd; Todorov, Vladimir T.; Hugo, Christian P. M.

    2014-01-01

    Mesangial cell injury has a major role in many CKDs. Because renin-positive precursor cells give rise to mesangial cells during nephrogenesis, this study tested the hypothesis that the same phenomenon contributes to glomerular regeneration after murine experimental mesangial injury. Mesangiolysis was induced by administration of an anti-mesangial cell serum in combination with LPS. In enhanced green fluorescent protein–reporter mice with constitutively labeled renin lineage cells, the size of...

  16. Controversies on glomerular filtration from Ludwig to the present.

    Science.gov (United States)

    Steinhausen, M; Endlich, K

    1996-01-01

    Since Ludwig's theory of filtration in the glomerulus is generally accepted, current research interest has focussed on the regulation of this process. The main determinants of glomerular filtration rate are glomerular capillary pressure and glomerular blood flow, which are adjusted via resistance changes in the pre- and postglomerular vasculature. Overall pre- and postglomerular resistances were first determined by micropuncture in superficial glomeruli. While the predominant source of postglomerular resistance is the efferent arteriole, several results indicate that preglomerular resistance might be rather uniformly distributed among all preglomerular vessels (interlobar, arcuate and interlobular arteries and afferent arterioles). Over the last decade, several techniques have been used to visualize renal vessels and to study the action of various vasoactive hormones thereon. Results obtained with the split hydronephrotic kidney model, which permits in vivo microscopy of all renal vessels, provide evidence for a differential regulation of the various preglomerular vessels by vasoactive hormones. In particular, mediators of inflammation almost selectively constrict interlobar and arcuate arteries. We conclude that, given the renal vascular architecture, differential regulation of preglomerular vessels can alter haemodynamic parameters specifically for different nephron populations.

  17. Shh-proteoglycan interactions regulate maturation of olfactory glomerular circuitry.

    Science.gov (United States)

    Persson, Laura; Witt, Rochelle M; Galligan, Meghan; Greer, Paul L; Eisner, Adriana; Pazyra-Murphy, Maria F; Datta, Sandeep R; Segal, Rosalind A

    2014-12-01

    The olfactory system relies on precise circuitry connecting olfactory sensory neurons (OSNs) and appropriate relay and processing neurons of the olfactory bulb (OB). In mammals, the exact correspondence between specific olfactory receptor types and individual glomeruli enables a spatially precise map of glomerular activation that corresponds to distinct odors. However, the mechanisms that govern the establishment and maintenance of the glomerular circuitry are largely unknown. Here we show that high levels of Sonic Hedgehog (Shh) signaling at multiple sites enable refinement and maintenance of olfactory glomerular circuitry. Mice expressing a mutant version of Shh (Shh(Ala/Ala)), with impaired binding to proteoglycan co-receptors, exhibit disproportionately small olfactory bulbs containing fewer glomeruli. Notably, in mutant animals the correspondence between individual glomeruli and specific olfactory receptors is lost, as olfactory sensory neurons expressing different olfactory receptors converge on the same glomeruli. These deficits arise at late stages in post-natal development and continue into adulthood, indicating impaired pruning of erroneous connections within the olfactory bulb. In addition, mature Shh(Ala/Ala) mice exhibit decreased proliferation in the subventricular zone (SVZ), with particular reduction in neurogenesis of calbindin-expressing periglomerular cells. Thus, Shh interactions with proteoglycan co-receptors function at multiple locations to regulate neurogenesis and precise olfactory connectivity, thereby promoting functional neuronal circuitry.

  18. Nanomaterial-modulated autophagy: underlying mechanisms and functional consequences.

    Science.gov (United States)

    Zheng, Wei; Wei, Min; Li, Song; Le, Weidong

    2016-06-01

    Autophagy is an essential lysosome-dependent process that controls the quality of the cytoplasm and maintains cellular homeostasis, and dysfunction of this protein degradation system is correlated with various disorders. A growing body of evidence suggests that nanomaterials (NMs) have autophagy-modulating effects, thus predicting a valuable and promising application potential of NMs in the diagnosis and treatment of autophagy-related diseases. NMs exhibit unique physical, chemical and biofunctional properties, which may endow NMs with capabilities to modulate autophagy via various mechanisms. The present review highlights the impacts of various NMs on autophagy and their functional consequences. The possible underlying mechanisms for NM-modulated autophagy are also discussed.

  19. Mammalian Autophagy: How Does It Work?

    Science.gov (United States)

    Bento, Carla F; Renna, Maurizio; Ghislat, Ghita; Puri, Claudia; Ashkenazi, Avraham; Vicinanza, Mariella; Menzies, Fiona M; Rubinsztein, David C

    2016-06-02

    Autophagy is a conserved intracellular pathway that delivers cytoplasmic contents to lysosomes for degradation via double-membrane autophagosomes. Autophagy substrates include organelles such as mitochondria, aggregate-prone proteins that cause neurodegeneration and various pathogens. Thus, this pathway appears to be relevant to the pathogenesis of diverse diseases, and its modulation may have therapeutic value. Here, we focus on the cell and molecular biology of mammalian autophagy and review the key proteins that regulate the process by discussing their roles and how these may be modulated by posttranslational modifications. We consider the membrane-trafficking events that impact autophagy and the questions relating to the sources of autophagosome membrane(s). Finally, we discuss data from structural studies and some of the insights these have provided.

  20. Mechanisms of mitochondria and autophagy crosstalk

    OpenAIRE

    Rambold, Angelika S; Lippincott-Schwartz, Jennifer

    2011-01-01

    Autophagy is a cellular survival pathway that recycles intracellular components to compensate for nutrient depletion and ensures the appropriate degradation of organelles. Mitochondrial number and health are regulated by mitophagy, a process by which excessive or damaged mitochondria are subjected to autophagic degradation. Autophagy is thus a key determinant for mitochondrial health and proper cell function. Mitophagic malfunction has been recently proposed to contribute to progressive neuro...

  1. Antidepressant indatraline induces autophagy and inhibits restenosis via suppression of mTOR/S6 kinase signaling pathway

    Science.gov (United States)

    Cho, Yoon Sun; Yen, Chih-na; Shim, Joong Sup; Kang, Dong Hoon; Kang, Sang Won; Liu, Jun O.; Kwon, Ho Jeong

    2016-01-01

    Indatraline is an antidepressive agent and a non-selective monoamine transporter inhibitor that blocks the reuptake of neurotransmitters (dopamine, serotonin, and norepinephrine). In this study, we report that indatraline induces autophagy via the suppression of mTOR/S6 kinase signaling. Autophagy induction was examined by a cell-based high content screening system using LysoTracker, which was followed by monodansylcadaverine staining and transmission electron microscope observation. Indatraline increased the number of EGFP-LC3 cells expressing autophagosomes in the cytoplasm. Conversion of LC3 was further validated by immunoblotting. Indatraline induced autophagy by affecting the AMPK/mTOR/S6K signaling axis and had no influence on the PI3K/AKT/ERK signaling. Moreover, indatraline induced autophagy in smooth muscle cells (SMCs); further, it exhibited therapeutic potential for restenosis by inhibiting SMC accumulation in a rat restenosis model. These results provide new insights into the role of monoamine transporters in autophagy regulation and identify indatraline as a novel agent for inducing autophagy. PMID:27694974

  2. RUFY4: Immunity piggybacking on autophagy?

    Science.gov (United States)

    Terawaki, Seigo; Camosseto, Voahirana; Pierre, Philippe; Gatti, Evelina

    2016-01-01

    Although autophagy is a highly conserved mechanism among species and cell types, few are the molecules involved with the autophagic process that display cell- or tissue- specific expression. We have unraveled the positive regulatory role on autophagy of RUFY4 (RUN and FYVE domain containing 4), which is expressed in subsets of immune cells, including dendritic cells (DCs). DCs orchestrate the eradication of pathogens by coordinating the action of the different cell types involved in microbe recognition and destruction during the immune response. To fulfill this function, DC display particular regulation of their endocytic and autophagy pathways in response to the immune environment. Autophagy flux is downmodulated in DCs upon microbe sensing, but is remarkably augmented, when cells are differentiated in the presence of the pleiotropic cytokine IL4 (interleukin 4). From gene expression studies aimed at comparing the impact of IL4 on DC differentiation, we identified RUFY4, as a novel regulator that augments autophagy flux and, when overexpressed, induces drastic membrane redistribution and strongly tethers lysosomes. RUFY4 is therefore one of the few known positive regulators of autophagy that is expressed in a cell-specific manner or under specific immunological conditions associated with IL4 expression such as allergic asthma.

  3. Extracellular Vesicles and Autophagy in Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Tianyang Gao

    2016-01-01

    Full Text Available Osteoarthritis (OA is a type of chronic joint disease that is characterized by the degeneration and loss of articular cartilage and hyperplasia of the synovium and subchondral bone. There is reasonable knowledge about articular cartilage physiology, biochemistry, and chondrocyte metabolism. However, the etiology and pathogenesis of OA remain unclear and need urgent clarification to guide the early diagnosis and treatment of OA. Extracellular vesicles (EVs are small membrane-linking particles that are released from cells. In recent decades, several special biological properties have been found in EV, especially in terms of cartilage. Autophagy plays a critical role in the regulation of cellular homeostasis. Likewise, more and more research has gradually focused on the effect of autophagy on chondrocyte proliferation and function in OA. The synthesis and release of EV are closely associated with autophagy. At the same time, both EV and autophagy play a role in OA development. Based on the mechanism of EV and autophagy in OA development, EV may be beneficial in the early diagnosis of OA; on the other hand, the combination of EV and autophagy-related regulatory drugs may provide insight into possible OA therapeutic strategies.

  4. Autophagy in stem and progenitor cells.

    Science.gov (United States)

    Rodolfo, Carlo; Di Bartolomeo, Sabrina; Cecconi, Francesco

    2016-02-01

    Autophagy is a highly conserved cellular process, responsible for the degradation and recycling of damaged and/or outlived proteins and organelles. This is the major cellular pathway, acting throughout the formation of cytosolic vesicles, called autophagosomes, for the delivering to lysosome. Recycling of cellular components through autophagy is a crucial step for cell homeostasis as well as for tissue remodelling during development. Impairment of this process has been related to the pathogenesis of various diseases, such as cancer and neurodegeneration, to the response to bacterial and viral infections, and to ageing. The ability of stem cells to self-renew and differentiate into the mature cells of the body renders this unique type of cell highly crucial to development and tissue renewal, not least in various diseases. During the last two decades, extensive knowledge about autophagy roles and regulation in somatic cells has been acquired; however, the picture about the role and the regulation of autophagy in the different types of stem cells is still largely unknown. Autophagy is a major player in the quality control and maintenance of cellular homeostasis, both crucial factors for stem cells during an organism's life. In this review, we have highlighted the most significant advances in the comprehension of autophagy regulation in embryonic and tissue stem cells, as well as in cancer stem cells and induced pluripotent cells.

  5. Autophagy and its neuroprotection in neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    Ping Gu; Avaneesh Jakkoju; Mingwei Wang; Weidong Le

    2011-01-01

    It has been suggested that protein misfolding and aggregation contribute significantly to the development of neurodegenerative diseases. Misfolded and aggregated proteins are cleared by ubiquitin proteasomal system (UPS) and by both Micro and Macro autophagy lysosomal pathway (ALP). Autophagosomal dysfunction has been implicated in an increasing number of diseases including neurodegenerative diseases. Autophagy is a cellular self-eating process that plays an important role in neuroprotection as well as neuronal injury and death. While a decrease in autophagic activity interferes with protein degradation and possibly organelle turnover, increased autophagy has been shown to facilitate the clearance of aggregation-prone proteins and promote neuronal survival in a number of disease models. On the other hand, too much autophagic activity can be detrimental, suggesting the regulation of autophagy is critical in dictating cell fate. In this review paper, we will discuss various aspects of ALP biology and its dual functions in neuronal cell death and survival. We will also evaluate the role of autophagy in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis. Finally, we will explore the therapeutic potential of autophagy modifiers in several neurodegenerative diseases.

  6. Control of autophagy by oncogenes and tumor suppressor genes.

    Science.gov (United States)

    Maiuri, M C; Tasdemir, E; Criollo, A; Morselli, E; Vicencio, J M; Carnuccio, R; Kroemer, G

    2009-01-01

    Multiple oncogenes (in particular phosphatidylinositol 3-kinase, PI3K; activated Akt1; antiapoptotic proteins from the Bcl-2 family) inhibit autophagy. Similarly, several tumor suppressor proteins (such as BH3-only proteins; death-associated protein kinase-1, DAPK1; the phosphatase that antagonizes PI3K, PTEN; tuberous sclerosic complex 1 and 2, TSC1 and TSC2; as well as LKB1/STK11) induce autophagy, meaning that their loss reduces autophagy. Beclin-1, which is required for autophagy induction acts as a haploinsufficient tumor suppressor protein, and other essential autophagy mediators (such as Atg4c, UVRAG and Bif-1) are bona fide oncosuppressors. One of the central tumor suppressor proteins, p53 exerts an ambiguous function in the regulation of autophagy. Within the nucleus, p53 can act as an autophagy-inducing transcription factor. Within the cytoplasm, p53 exerts a tonic autophagy-inhibitory function, and its degradation is actually required for the induction of autophagy. The role of autophagy in oncogenesis and anticancer therapy is contradictory. Chronic suppression of autophagy may stimulate oncogenesis. However, once a tumor is formed, autophagy inhibition may be a therapeutic goal for radiosensitization and chemosensitization. Altogether, the current state-of-the art suggests a complex relationship between cancer and deregulated autophagy that must be disentangled by further in-depth investigation.

  7. High throughput screening for drug discovery of autophagy modulators.

    Science.gov (United States)

    Shu, Chih-Wen; Liu, Pei-Feng; Huang, Chun-Ming

    2012-11-01

    Autophagy is an evolutionally conserved process in cells for cleaning abnormal proteins and organelles in a lysosome dependent manner. Growing studies have shown that defects or induced autophagy contributes to many diseases including aging, neurodegeneration, pathogen infection, and cancer. However, the precise involvement of autophagy in health and disease remains controversial because the theories are built on limited assays and chemical modulators, indicating that the role of autophagy in diseases may require further verification. Many food and drug administration (FDA) approved drugs modulate autophagy signaling, suggesting that modulation of autophagy with pharmacological agonists or antagonists provides a potential therapy for autophagy-related diseases. This suggestion raises an attractive issue on drug discovery for exploring chemical modulators of autophagy. High throughput screening (HTS) is becoming a powerful tool for drug discovery that may accelerate screening specific autophagy modulators to clarify the role of autophagy in diseases. Herein, this review lays out current autophagy assays to specifically measure autophagy components such as LC3 (mammalian homologue of yeast Atg8) and Atg4. These assays are feasible or successful for HTS with certain chemical libraries, which might be informative for this intensively growing field as research tools and hopefully developing new drugs for autophagy-related diseases.

  8. Modulation of inflammation by autophagy: consequences for Crohn's disease.

    NARCIS (Netherlands)

    Plantinga, T.S.; Joosten, L.A.B.; Meer, J.W.M. van der; Netea, M.G.

    2012-01-01

    Autophagy, the cellular machinery for targeting intracellular components for lysosomal degradation, is critically involved in the host defence to pathogenic microorganisms. Recent studies have unveiled several aspects of the immune response that are regulated by autophagy, including antigen presenta

  9. Autophagy in acute brain injury: feast, famine, or folly?

    Science.gov (United States)

    Smith, Craig M; Chen, Yaming; Sullivan, Mara L; Kochanek, Patrick M; Clark, Robert S B

    2011-07-01

    In the central nervous system, increased autophagy has now been reported after traumatic brain and spinal cord injury, cerebral ischemia, intracerebral hemorrhage, and seizures. This increase in autophagy could be physiologic, converting damaged or dysfunctional proteins, lipids, and/or organelles to their amino acid and fatty acid components for recycling. On the other hand, this increase in autophagy could be supraphysiologic, perhaps consuming and eliminating functional proteins, lipids, and/or organelles as well. Whether an increase in autophagy is beneficial (feast) or detrimental (famine) in brain likely depends on both the burden of intracellular substrate targeted for autophagy and the capacity of the cell's autophagic machinery. Of course, increased autophagy observed after brain injury could also simply be an epiphenomenon (folly). These divergent possibilities have clear ramifications for designing therapeutic strategies targeting autophagy after acute brain injury and are the subject of this review. This article is part of a Special Issue entitled "Autophagy and protein degradation in neurological diseases."

  10. Analysis of autophagy genes in microalgae: Chlorella as a potential model to study mechanism of autophagy.

    Directory of Open Access Journals (Sweden)

    Qiao Jiang

    Full Text Available BACKGROUND: Microalgae, with the ability to mitigate CO(2 emission and produce carbohydrates and lipids, are considered one of the most promising resources for producing bioenergy. Recently, we discovered that autophagy plays a critical role in the metabolism of photosynthetic system and lipids production. So far, more than 30-autophagy related (ATG genes in all subtypes of autophagy have been identified. However, compared with yeast and mammals, in silico and experimental research of autophagy pathways in microalgae remained limited and fragmentary. PRINCIPAL FINDINGS: In this article, we performed a genome-wide analysis of ATG genes in 7 microalgae species and explored their distributions, domain structures and evolution. Eighteen "core autophagy machinery" proteins, four mammalian-specific ATG proteins and more than 30 additional proteins (including "receptor-adaptor" complexes in all subtypes of autophagy were analyzed. Data revealed that receptor proteins in cytoplasm-to-vacuole targeting and mitophagy seem to be absent in microalgae. However, most of the "core autophagy machinery" and mammalian-specific proteins are conserved among microalgae, except for the ATG9-cycling system in Chlamydomonas reinhardtii and the second ubiquitin-like protein conjugation complex in several algal species. The catalytic and binding residues in ATG3, ATG5, ATG7, ATG8, ATG10 and ATG12 are also conserved and the phylogenetic tree of ATG8 coincides well with the phylogenies. Chlorella contains the entire set of the core autophagy machinery. In addition, RT-PCR analysis verified that all crucial ATG genes tested are expressed during autophagy in both Chlorella and Chlamydomonas reinhardtii. Finally, we discovered that addition of 3-Methyladenine (a PI3K specific inhibitor could suppress the formation of autophagic vacuoles in Chlorella. CONCLUSIONS: Taken together, Chlorella may represent a potential model organism to investigate autophagy pathways in

  11. Berberine attenuates autophagy in adipocytes by targeting BECN1

    OpenAIRE

    Deng, Yujie; Xu, Jun; Zhang, Xiaoyan; Yang, Jian; Zhang, Di; Huang, Jian; Lv, Pengfei; Shen, Weili; Yang, Ying

    2014-01-01

    The lysosomal degradation pathway, autophagy, is essential for the maintenance of cellular homeostasis. Recently, autophagy has been demonstrated to be required in the process of adipocyte conversion. However, its role in mature adipocytes under physiological and pathological conditions remains unclear. Here, we report a major function of BECN1 in the regulation of basal autophagy in mature adipocytes. We also show that berberine, a natural plant alkaloid, inhibits basal autophagy in adipocyt...

  12. Effects of sulindac and naproxen in patients with chronic glomerular disease

    DEFF Research Database (Denmark)

    Kamper, A L; Strandgaard, S; Christensen, P;

    1986-01-01

    Eight patients with chronic glomerulonephritis were treated with either naproxen or sulindac in an open randomized study to observe their effects on the urinary excretion of prostaglandins and renal function. Both drugs were given for 7 days. Naproxen caused a decrease (p less than 0.01) of 80......% in prostaglandin PGE2 and decrease (p less than 0.01) of 55% in prostaglandin PGF2 alpha. Sulindac caused a decrease (p = 0.01) of 37% in PGE2 and a decrease (p less than 0.05) in PGF2 alpha of 13%. The decrease in urinary excretion of prostaglandins were greater (p less than 0.05) during the naproxen treatment....... Sulindac did not change any of these parameters significantly. In conclusion, sulindac affects renal prostaglandin synthesis to a significantly minor degree than naproxen and contrary to naproxen it does not influence the renal function in patients with chronic glomerular disease....

  13. Injury to the Endothelial Surface Layer Induces Glomerular Hyperfiltration Rats with Early-Stage Diabetes

    Directory of Open Access Journals (Sweden)

    Chunyang Zhang

    2014-01-01

    Full Text Available Glomerular endothelial surface layer (ESL may play a role in the mechanisms of albuminuria in diabetic nephropathy, which lack evidence in vivo. The effects of high glucose on the passage of albumin across the glomerular ESL were analysed in streptozotocin-induced diabetic Sprague-Dawley rats for 4 weeks. Albuminuria and glomerular mesangial matrix were significantly increased in diabetic rats. The passage of albumin across the ESL, as measured by albumin-colloid gold particle density in the glomerular basement membrane (GBM, was increased significantly in diabetic rats. The thickness of the glomerular ESL, examined indirectly by infusing Intralipid into vessels using an electron microscope, was significantly decreased and the GBM exhibited little change in diabetic rats. In summary, the glomerular ESL may play a role in the pathogenesis of albuminuria in rats with early-stage diabetes.

  14. From the urea cycle to autophagy: Alfred J. Meijer

    NARCIS (Netherlands)

    D.J. Klionsky; A.J. Meijer

    2011-01-01

    Now that many of the components of the autophagy machinery have been identified, in particular the autophagy-related (Atg) proteins, increasing focus is being directed toward the role of autophagy in health and disease. Accordingly, it is of ever-greater importance to understand the central role of

  15. Autophagy modulates the Mycobacterium tuberculosis-induced cytokine response

    NARCIS (Netherlands)

    Kleinnijenhuis, J.; Oosting, M.; Plantinga, T.S.; Meer, J.W.M. van der; Joosten, L.A.B.; Crevel, R. van; Netea, M.G.

    2011-01-01

    Both autophagy and pro-inflammatory cytokines are involved in the host defence against mycobacteria, but little is known regarding the effect of autophagy on Mycobacterium tuberculosis (MTB)-induced cytokine production. In the present study, we assessed the effect of autophagy on production of monoc

  16. Phosphorylation of the autophagy receptor optineurin restricts Salmonella growth

    DEFF Research Database (Denmark)

    Wild, Philipp; Farhan, Hesso; McEwan, David G;

    2011-01-01

    Selective autophagy can be mediated via receptor molecules that link specific cargoes to the autophagosomal membranes decorated by ubiquitin-like microtubule-associated protein light chain 3 (LC3) modifiers. Although several autophagy receptors have been identified, little is known about mechanisms...... be a general mechanism for regulation of cargo-selective autophagy....

  17. Autophagy and Retromer Components in Plant Innate Immunity

    DEFF Research Database (Denmark)

    Munch, David

    -hormone salicylic acid. Here, I present data that make it clear that NPR1 does not directly regulate autophagy, but instead control stress responses that indirectly activate autophagy. The observations presented will also clarify why autophagy has been described as being both a pro-death and pro-life pathway under...

  18. Intravital imaging of podocyte calcium in glomerular injury and disease.

    Science.gov (United States)

    Burford, James L; Villanueva, Karie; Lam, Lisa; Riquier-Brison, Anne; Hackl, Matthias J; Pippin, Jeffrey; Shankland, Stuart J; Peti-Peterdi, János

    2014-05-01

    Intracellular calcium ([Ca²⁺]i) signaling mediates physiological and pathological processes in multiple organs, including the renal podocyte; however, in vivo podocyte [Ca²⁺]i dynamics are not fully understood. Here we developed an imaging approach that uses multiphoton microscopy (MPM) to directly visualize podocyte [Ca²⁺]i dynamics within the intact kidneys of live mice expressing a fluorescent calcium indicator only in these cells. [Ca²⁺]i was at a low steady-state level in control podocytes, while Ang II infusion caused a minor elevation. Experimental focal podocyte injury triggered a robust and sustained elevation of podocyte [Ca²⁺]i around the injury site and promoted cell-to-cell propagating podocyte [Ca²⁺]i waves along capillary loops. [Ca²⁺]i wave propagation was ameliorated by inhibitors of purinergic [Ca²⁺]i signaling as well as in animals lacking the P2Y2 purinergic receptor. Increased podocyte [Ca²⁺]i resulted in contraction of the glomerular tuft and increased capillary albumin permeability. In preclinical models of renal fibrosis and glomerulosclerosis, high podocyte [Ca²⁺]i correlated with increased cell motility. Our findings provide a visual demonstration of the in vivo importance of podocyte [Ca²⁺]i in glomerular pathology and suggest that purinergic [Ca²⁺]i signaling is a robust and key pathogenic mechanism in podocyte injury. This in vivo imaging approach will allow future detailed investigation of the molecular and cellular mechanisms of glomerular disease in the intact living kidney.

  19. Ultrastructural model for size selectivity in glomerular filtration.

    Science.gov (United States)

    Edwards, A; Daniels, B S; Deen, W M

    1999-06-01

    A theoretical model was developed to relate the size selectivity of the glomerular barrier to the structural characteristics of the individual layers of the capillary wall. Thicknesses and other linear dimensions were evaluated, where possible, from previous electron microscopic studies. The glomerular basement membrane (GBM) was represented as a homogeneous material characterized by a Darcy permeability and by size-dependent hindrance coefficients for diffusion and convection, respectively; those coefficients were estimated from recent data obtained with isolated rat GBM. The filtration slit diaphragm was modeled as a single row of cylindrical fibers of equal radius but nonuniform spacing. The resistances of the remainder of the slit channel, and of the endothelial fenestrae, to macromolecule movement were calculated to be negligible. The slit diaphragm was found to be the most restrictive part of the barrier. Because of that, macromolecule concentrations in the GBM increased, rather than decreased, in the direction of flow. Thus the overall sieving coefficient (ratio of Bowman's space concentration to that in plasma) was predicted to be larger for the intact capillary wall than for a hypothetical structure with no GBM. In other words, because the slit diaphragm and GBM do not act independently, the overall sieving coefficient is not simply the product of those for GBM alone and the slit diaphragm alone. Whereas the calculated sieving coefficients were sensitive to the structural features of the slit diaphragm and to the GBM hindrance coefficients, variations in GBM thickness or filtration slit frequency were predicted to have little effect. The ability of the ultrastructural model to represent fractional clearance data in vivo was at least equal to that of conventional pore models with the same number of adjustable parameters. The main strength of the present approach, however, is that it provides a framework for relating structural findings to the size

  20. Proximal tubular hypertrophy and enlarged glomerular and proximal tubular urinary space in obese subjects with proteinuria.

    Directory of Open Access Journals (Sweden)

    Ana Tobar

    Full Text Available BACKGROUND: Obesity is associated with glomerular hyperfiltration, increased proximal tubular sodium reabsorption, glomerular enlargement and renal hypertrophy. A single experimental study reported an increased glomerular urinary space in obese dogs. Whether proximal tubular volume is increased in obese subjects and whether their glomerular and tubular urinary spaces are enlarged is unknown. OBJECTIVE: To determine whether proximal tubules and glomerular and tubular urinary space are enlarged in obese subjects with proteinuria and glomerular hyperfiltration. METHODS: Kidney biopsies from 11 non-diabetic obese with proteinuria and 14 non-diabetic lean patients with a creatinine clearance above 50 ml/min and with mild or no interstitial fibrosis were retrospectively analyzed using morphometric methods. The cross-sectional area of the proximal tubular epithelium and lumen, the volume of the glomerular tuft and of Bowman's space and the nuclei number per tubular profile were estimated. RESULTS: Creatinine clearance was higher in the obese than in the lean group (P=0.03. Proteinuria was similarly increased in both groups. Compared to the lean group, the obese group displayed a 104% higher glomerular tuft volume (P=0.001, a 94% higher Bowman's space volume (P=0.003, a 33% higher cross-sectional area of the proximal tubular epithelium (P=0.02 and a 54% higher cross-sectional area of the proximal tubular lumen (P=0.01. The nuclei number per proximal tubular profile was similar in both groups, suggesting that the increase in tubular volume is due to hypertrophy and not to hyperplasia. CONCLUSIONS: Obesity-related glomerular hyperfiltration is associated with proximal tubular epithelial hypertrophy and increased glomerular and tubular urinary space volume in subjects with proteinuria. The expanded glomerular and urinary space is probably a direct consequence of glomerular hyperfiltration. These effects may be involved in the pathogenesis of obesity

  1. High glucose stimulates the expression of erythropoietin in rat glomerular epithelial cells

    OpenAIRE

    Lim, Seul Ki; Park, Soo Hyun

    2011-01-01

    It has been reported that the levels of erythropoietin are associated with diabetes mellitus. Glomerular epithelial cells, located in the renal cortex, play an important role in the regulation of kidney function and hyperglycemia-induced cell loss of glomerular epithelial cells is implicated in the onset of diabetic nephropathy. This study investigated the effect of high glucose on erythropoietin and erythropoietin receptor expression in rat glomerular epithelial cells. We found that 25 mM D-...

  2. Indexing Glomerular Filtration Rate to Body Surface Area

    DEFF Research Database (Denmark)

    Redal-Baigorri, Belén; Rasmussen, Knud; Heaf, James Goya

    2014-01-01

    BACKGROUND: Kidney function is mostly expressed in terms of glomerular filtration rate (GFR). A common feature is the expression as ml/min per 1.73 m(2) , which represents the adjustment of the individual kidney function to a standard body surface area (BSA) to allow comparison between individuals....... We investigated the impact of indexing GFR to BSA in cancer patients, as this BSA indexation might affect the reported individual kidney function. METHODS: Cross-sectional study of 895 adults who had their kidney function measured with (51) chrome ethylene diamine tetraacetic acid. Mean values of BSA...

  3. Glomerular microcapillary thrombosis demonstrated by the new technique of immunocathodoluminescence.

    Science.gov (United States)

    Schmidt, E. H.; Bröcker, W.; Wagner, H.; Pfefferkorn, G.; Beller, F. K.

    1975-01-01

    Fluorescein-labeled antigen-antibody complexes could be made visible by scanning electron microscopy using an intensifying device. This new method of immunocathodoluminescence was demonstrated on cryostat sections of rat kidneys containing glomerular fibrin as the result of endotoxin infusion. The resulting photographs correspond with those obtained by immunofluorescent microscopy. The advantage of this technique is, however, the larger depth of focus. By using thinner cyostat sections it is expected that the higher resolution of scanning microscopy will provide even better details in three dimensions. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:1101704

  4. A neural network model for olfactory glomerular activity prediction

    Science.gov (United States)

    Soh, Zu; Tsuji, Toshio; Takiguchi, Noboru; Ohtake, Hisao

    2012-12-01

    Recently, the importance of odors and methods for their evaluation have seen increased emphasis, especially in the fragrance and food industries. Although odors can be characterized by their odorant components, their chemical information cannot be directly related to the flavors we perceive. Biological research has revealed that neuronal activity related to glomeruli (which form part of the olfactory system) is closely connected to odor qualities. Here we report on a neural network model of the olfactory system that can predict glomerular activity from odorant molecule structures. We also report on the learning and prediction ability of the proposed model.

  5. Mechanisms responsible for decreased glomerular filtration in hibernation and hypothermia

    Science.gov (United States)

    Tempel, G. E.; Musacchia, X. J.; Jones, S. B.

    1977-01-01

    Measurements of blood pressure, heart rate, red blood cell and plasma volumes, and relative distribution of cardiac output were made on hibernating and hypothermic adult male and female golden hamsters weighing 120-140 g to study the mechanisms underlying the elimination or marked depression of renal function in hibernation and hypothermia. The results suggest that the elimination or marked depression in renal function reported in hibernation and hypothermia may partly be explained by alterations in cardiovascular system function. Renal perfusion pressure which decreases nearly 60% in both hibernation and hypothermia and a decrease in plasma volume of roughly 35% in the hypothermic animal might both be expected to markedly alter glomerular function.

  6. Influences of ischemic preconditioning on autophagy in rats with cerebral ischemia reperfusion injury%缺血预处理对大鼠脑缺血再灌注自噬的影响

    Institute of Scientific and Technical Information of China (English)

    石秋艳; 刘冰; 张春阳; 范亚霞; 孙原; 杨斌

    2014-01-01

    Objective To observe the effect of ischemic preconditioning ( IPC) effect on cerebral ischemia reperfusion in rat hippocampus of autophagy .Methods According to method of Zea-Longa filamene , rats middle cerebral artery ischemi-a-reperfusion model were established , the experimental animal were randomly divided into 3 groups: sham operation group (Sham group, n =10), ischemia reperfusion group (I/R group, n =10), IPC treatment group (IPC group, n =30), in IPC group, according to ischemic preconditioning time , rats were divided into 1 d, 3 d, 5 d subgroups, 10 rats in each group.Af-ter ischemia 2 h and reperfusion 24 h, immunohistochemical method was used to detect the autophagy associated protein BEC -LIN L, LC3-II expression, transmission electron microscope in nerve cell autophagy and lysosomal activation and cell ultra -structure changes .Results ( 1 ) Neurological dysfunction score: compared with Sham group , I/R group and IPC group showed varying degrees of nerve dysfunction ( P <0.01), I/R group of symptoms in IPC subgroups ( P <0.05).(2) The volume of cerebral infarction:compared with Sham group , I/R group and IPC group had different degree of infarction ( P <0.01);IPC group was lower than that in I/R group ( P <0.01), 3 d subgroup was less than 1 d and 5 d subgroup ( P <0.01).(3) Immunohistochemical staining:compared with Sham group , I/R group and IPC group, the number of BECLIN 1 and LC3-II positive cells ( P <0.01), the expression of IPC positive cells was significantly lower than that of I /R group (P <0.01), IPC 3 d subgroup was less than 1 d, 5 d subgroup ( P <0.01).(4) The change of brain tissue ultrastructure morphology of cells:Sham group was normal;I/R group and IPC group showed varying amounts of autophagy , in different peri-od and or autophagic lysosome , mitochondria swelling, rupture of membranes, vesicles, lysosomes increased significantly ,visi-ble deformation of secondary lysosomes ,Golgi fragmentation;IPC group autophagy and the number

  7. A molecular view of autophagy in Lepidoptera.

    Science.gov (United States)

    Romanelli, Davide; Casati, Barbara; Franzetti, Eleonora; Tettamanti, Gianluca

    2014-01-01

    Metamorphosis represents a critical phase in the development of holometabolous insects, during which the larval body is completely reorganized: in fact, most of the larval organs undergo remodeling or completely degenerate before the final structure of the adult insect is rebuilt. In the past, increasing evidence emerged concerning the intervention of autophagy and apoptosis in the cell death processes that occur in larval organs of Lepidoptera during metamorphosis, but a molecular characterization of these pathways was undertaken only in recent years. In addition to developmentally programmed autophagy, there is growing interest in starvation-induced autophagy. Therefore we are now entering a new era of research on autophagy that foreshadows clarification of the role and regulatory mechanisms underlying this self-digesting process in Lepidoptera. Given that some of the most important lepidopteran species of high economic importance, such as the silkworm, Bombyx mori, belong to this insect order, we expect that this information on autophagy will be fully exploited not only in basic research but also for practical applications.

  8. Autophagy and Liver Ischemia-Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Raffaele Cursio

    2015-01-01

    Full Text Available Liver ischemia-reperfusion (I-R injury occurs during liver resection, liver transplantation, and hemorrhagic shock. The main mode of liver cell death after warm and/or cold liver I-R is necrosis, but other modes of cell death, as apoptosis and autophagy, are also involved. Autophagy is an intracellular self-digesting pathway responsible for removal of long-lived proteins, damaged organelles, and malformed proteins during biosynthesis by lysosomes. Autophagy is found in normal and diseased liver. Although depending on the type of ischemia, warm and/or cold, the dynamic process of liver I-R results mainly in adenosine triphosphate depletion and in production of reactive oxygen species (ROS, leads to both, a local ischemic insult and an acute inflammatory-mediated reperfusion injury, and results finally in cell death. This process can induce liver dysfunction and can increase patient morbidity and mortality after liver surgery and hemorrhagic shock. Whether autophagy protects from or promotes liver injury following warm and/or cold I-R remains to be elucidated. The present review aims to summarize the current knowledge in liver I-R injury focusing on both the beneficial and the detrimental effects of liver autophagy following warm and/or cold liver I-R.

  9. Avaliação do ritmo de filtração glomerular Assessment of glomerular filtration rate

    Directory of Open Access Journals (Sweden)

    Gianna Mastroianni Kirsztajn

    2007-08-01

    Full Text Available A medida do ritmo de filtração glomerular (RFG é a prova laboratorial mais utilizada na avaliação da função renal. Para tanto, usam-se marcadores indiretos, como as determinações de creatinina e cistatina C no sangue, ou procede-se à determinação do RFG propriamente dito, com indicadores como inulina; contrastes iodados, marcados ou não; e outras substâncias. O exame mais solicitado para avaliação do RFG no laboratório de patologia clínica é a dosagem da creatinina sérica. Em algumas condições, entretanto, o resultado encontrado da creatinina sérica deve ser corrigido (através da utilização de fórmulas que levam em consideração características próprias do indivíduo para ser devidamente interpretado. De fato, a inulina ainda é vista como marcador ideal de filtração glomerular, mas seu uso não se destina à prática clínica, de modo que ainda hoje persiste a busca por testes adequados para uso rotineiro.Glomerular filtration rate (GFR determination is the most frequently used laboratorial test to evaluate renal function. Indirect markers as blood determination of creatinine and cystatin C are used with this purpose, as well as the direct determination of GFR, with indicators like inulin; iodated contrasts, radioactive or not; and others. Serum creatinine is the test that is most commonly performed in order to evaluate GFR in the clinical pathology laboratory. However, in some conditions, aiming at the adequate interpretation of the test, the result of serum creatinine must be corrected (by using formulas that include individual characteristics of the subjects. In fact, inulin is still seen as the ideal marker of glomerular filtration, but its use is not directed to clinical practice; then the search for appropriate tests for routine use continues.

  10. Regression of glomerular injury by losartan in experimental diabetic nephropathy.

    Science.gov (United States)

    Teles, Flávio; Machado, Flávia G; Ventura, Bianca H; Malheiros, Denise M A C; Fujihara, Clarice K; Silva, Luís F F; Zatz, Roberto

    2009-01-01

    Many features of chronic kidney disease may be reversed, but it is unclear whether advanced lesions, such as adhesions of sclerotic glomerular tufts to Bowman's capsule (synechiae), can resolve during treatment. We previously showed, using a renal ablation model, that the renoprotective effect of the AT-1 receptor blocker, losartan, is dose-dependent. Here we determined if moderate and advanced glomerular lesions, associated with streptozotocin-induced diabetes, regress with conventional or high-dose losartan treatment. Using daily insulin injection for 10 months, we maintained diabetic adult male Munich-Wistar rats in a state of moderate hyperglycemia. Following this period, some rats continued to receive insulin with or without conventional or high-dose losartan for an additional 2 months. Diabetic rats pretreated with insulin for 10 months and age-matched non-diabetic rats served as controls. Mesangial expansion was found in the control diabetic rats and was exacerbated in those rats maintained on only insulin for an additional 2 months. Conventional and high-dose losartan treatments reduced this mesangial expansion and the severity of synechiae lesions below that found prior to treatment; however, the frequency of the latter was unchanged. There was no dose-response effect of losartan. Our results show that regression of mesangial expansion and contraction of sclerotic lesions is feasible in the treatment of diabetes, but complete resolution of advanced glomerulosclerosis may be hard to achieve.

  11. Cystinosis (ctns) zebrafish mutant shows pronephric glomerular and tubular dysfunction

    Science.gov (United States)

    Elmonem, Mohamed A.; Khalil, Ramzi; Khodaparast, Ladan; Khodaparast, Laleh; Arcolino, Fanny O.; Morgan, Joseph; Pastore, Anna; Tylzanowski, Przemko; Ny, Annelii; Lowe, Martin; de Witte, Peter A.; Baelde, Hans J.; van den Heuvel, Lambertus P.; Levtchenko, Elena

    2017-01-01

    The human ubiquitous protein cystinosin is responsible for transporting the disulphide amino acid cystine from the lysosomal compartment into the cytosol. In humans, Pathogenic mutations of CTNS lead to defective cystinosin function, intralysosomal cystine accumulation and the development of cystinosis. Kidneys are initially affected with generalized proximal tubular dysfunction (renal Fanconi syndrome), then the disease rapidly affects glomeruli and progresses towards end stage renal failure and multiple organ dysfunction. Animal models of cystinosis are limited, with only a Ctns knockout mouse reported, showing cystine accumulation and late signs of tubular dysfunction but lacking the glomerular phenotype. We established and characterized a mutant zebrafish model with a homozygous nonsense mutation (c.706 C > T; p.Q236X) in exon 8 of ctns. Cystinotic mutant larvae showed cystine accumulation, delayed development, and signs of pronephric glomerular and tubular dysfunction mimicking the early phenotype of human cystinotic patients. Furthermore, cystinotic larvae showed a significantly increased rate of apoptosis that could be ameliorated with cysteamine, the human cystine depleting therapy. Our data demonstrate that, ctns gene is essential for zebrafish pronephric podocyte and proximal tubular function and that the ctns-mutant can be used for studying the disease pathogenic mechanisms and for testing novel therapies for cystinosis. PMID:28198397

  12. Etiopathology of chronic tubular, glomerular and renovascular nephropathies: Clinical implications

    Directory of Open Access Journals (Sweden)

    Ortiz Alberto

    2011-01-01

    Full Text Available Abstract Chronic kidney disease (CKD comprises a group of pathologies in which the renal excretory function is chronically compromised. Most, but not all, forms of CKD are progressive and irreversible, pathological syndromes that start silently (i.e. no functional alterations are evident, continue through renal dysfunction and ends up in renal failure. At this point, kidney transplant or dialysis (renal replacement therapy, RRT becomes necessary to prevent death derived from the inability of the kidneys to cleanse the blood and achieve hydroelectrolytic balance. Worldwide, nearly 1.5 million people need RRT, and the incidence of CKD has increased significantly over the last decades. Diabetes and hypertension are among the leading causes of end stage renal disease, although autoimmunity, renal atherosclerosis, certain infections, drugs and toxins, obstruction of the urinary tract, genetic alterations, and other insults may initiate the disease by damaging the glomerular, tubular, vascular or interstitial compartments of the kidneys. In all cases, CKD eventually compromises all these structures and gives rise to a similar phenotype regardless of etiology. This review describes with an integrative approach the pathophysiological process of tubulointerstitial, glomerular and renovascular diseases, and makes emphasis on the key cellular and molecular events involved. It further analyses the key mechanisms leading to a merging phenotype and pathophysiological scenario as etiologically distinct diseases progress. Finally clinical implications and future experimental and therapeutic perspectives are discussed.

  13. 连续个性化追踪对农民工新生儿遗传性肾小球疾病肾功能恢复的影响%Influence of Continuous Personalized Tracking on Renal Function Recovery of Migrant Workers' Newborns with Hereditary Glomerular Diseases

    Institute of Scientific and Technical Information of China (English)

    黄笑群; 宋敏; 于生友; 于力

    2016-01-01

    Objective To evaluate the effect of continuous personalized tracking on renal function recovery of migrant workers' newborns with hereditary glomerular diseases. Methods Migrant worker parents of 76 newborns with hereditary glomerular diseases were divided into two groups equally. The control group accepted conventional telephone interviews and regular back-to-hospital reviews, while the observation group accepted continuous personalized tracking given by the responsible nurse for extended care service. Results Six months after discharge, the Cys C, Urea and SCR levels of observation were significantly lower than those of control group, and parents' awareness rate of health education and satisfaction degree to extended care service were significantly higher than those of control group (P<0.01). Conclusions Continuous personalized tracking can improve parents' compliance, nurses' behaviors and parents' satisfaction degree, which has a positive impact on renal function recovery of newborns.%目的:探讨连续个性化追踪对农民工新生儿遗传性肾小球疾病肾功能恢复的效果。方法将76例农民工新生儿遗传性肾小球疾病患儿及其家长均分为两组,对照组进行常规电话回访及定期来院复查,观察组由责任护士以连续个性化追踪形式进行延续护理服务。结果6个月后,观察组患儿的Cys C、 Urea、 SCR水平显著低于对照组,观察组家长对健康教育内容的知晓率、对延续护理服务的满意度均显著高于对照组,差异均有显著统计学意义(P<0.01)。结论连续个性化追踪可以提高家长依从性、护士执行力及家长满意度,有利于患儿肾功能的恢复。

  14. Induction of autophagy by spermidine promotes longevity.

    Science.gov (United States)

    Eisenberg, Tobias; Knauer, Heide; Schauer, Alexandra; Büttner, Sabrina; Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Ring, Julia; Schroeder, Sabrina; Magnes, Christoph; Antonacci, Lucia; Fussi, Heike; Deszcz, Luiza; Hartl, Regina; Schraml, Elisabeth; Criollo, Alfredo; Megalou, Evgenia; Weiskopf, Daniela; Laun, Peter; Heeren, Gino; Breitenbach, Michael; Grubeck-Loebenstein, Beatrix; Herker, Eva; Fahrenkrog, Birthe; Fröhlich, Kai-Uwe; Sinner, Frank; Tavernarakis, Nektarios; Minois, Nadege; Kroemer, Guido; Madeo, Frank

    2009-11-01

    Ageing results from complex genetically and epigenetically programmed processes that are elicited in part by noxious or stressful events that cause programmed cell death. Here, we report that administration of spermidine, a natural polyamine whose intracellular concentration declines during human ageing, markedly extended the lifespan of yeast, flies and worms, and human immune cells. In addition, spermidine administration potently inhibited oxidative stress in ageing mice. In ageing yeast, spermidine treatment triggered epigenetic deacetylation of histone H3 through inhibition of histone acetyltransferases (HAT), suppressing oxidative stress and necrosis. Conversely, depletion of endogenous polyamines led to hyperacetylation, generation of reactive oxygen species, early necrotic death and decreased lifespan. The altered acetylation status of the chromatin led to significant upregulation of various autophagy-related transcripts, triggering autophagy in yeast, flies, worms and human cells. Finally, we found that enhanced autophagy is crucial for polyamine-induced suppression of necrosis and enhanced longevity.

  15. IKK connects autophagy to major stress pathways.

    Science.gov (United States)

    Criollo, Alfredo; Senovilla, Laura; Authier, Hélène; Maiuri, Maria Chiara; Morselli, Eugenia; Vitale, Ilio; Kepp, Oliver; Tasdemir, Ezgi; Galluzzi, Lorenzo; Shen, Shensi; Tailler, Maximilien; Delahaye, Nicolas; Tesniere, Antoine; De Stefano, Daniela; Younes, Aména Ben; Harper, Francis; Pierron, Gérard; Lavandero, Sergio; Zitvogel, Laurence; Israel, Alain; Baud, Véronique; Kroemer, Guido

    2010-01-01

    Cells respond to stress by activating cytoplasmic mechanisms as well as transcriptional programs that can lead to adaptation or death. Autophagy represents an important cytoprotective response that is regulated by both transcriptional and transcription-independent pathways. NFkappaB is perhaps the transcription factor most frequently activated by stress and has been ascribed with either pro- or anti-autophagic functions, depending on the cellular context. Our results demonstrate that activation of the IKK (IkappaB kinase) complex, which is critical for the stress-elicited activation of NFkappaB, is sufficient to promote autophagy independent of NFkappaB, and that IKK is required for the optimal induction of autophagy by both physiological and pharmacological autophagic triggers.

  16. Autophagy is an inflammation-related defensive mechanism against disease.

    Science.gov (United States)

    Joven, Jorge; Guirro, Maria; Mariné-Casadó, Roger; Rodríguez-Gallego, Esther; Menéndez, Javier A

    2014-01-01

    The inflammatory response is an energy-intensive process. Consequently, metabolism is closely associated with immune function. The autophagy machinery plays a role in metabolism by providing energy but may also be used to attack invading pathogens (xenophagy). The autophagy machinery may function to protect against not only the threats of infection but also the threats of the host's own response acting on the central immunological tolerance and the negative regulation of innate and inflammatory signaling. The balance between too little and too much autophagy is critical for the survival of immune cells because autophagy is linked to type 2-cell death programmed necrosis and apoptosis. Changes in inflammatory cells are driven by extracellular signals; however, the mechanisms by which cytokines mediate autophagy regulation and govern immune cell function remain unknown. Certain cytokines increase autophagy, whereas others inhibit autophagy. The relationship between autophagy and inflammation is also important in the pathogenesis of metabolic, non-communicable diseases. Inflammation per se is not the cause of obesity-associated diseases, but it is secondary to both the positive energy balance and the specific cellular responses. In metabolic tissues, the suppression of autophagy increases inflammation with the overexpression of cytokines, resulting in an activation of autophagy. The physiological role of these apparently contradictory findings remains uncertain but exemplifies future challenges in the therapeutic modulation of autophagy in the management of disease.

  17. What to Eat: Evidence for Selective Autophagy in Plants

    Institute of Scientific and Technical Information of China (English)

    Brice E.Floyd; Stephanie C.Morriss; Gustavo C.Maclntosh; Diane C.Bassham

    2012-01-01

    Autophagy is a macromolecular degradation pathway by which cells recycle their contents as a developmental process,house-keeping mechanism,and response to environmental stress.In plants,autophagy involves the sequestration of cargo to be degraded,transport to the cell vacuole in a double-membrane bound autophagosome,and subsequent degradation by lytic enzymes.Autophagy has generally been considered to be a non-selective mechanism of degradation.However,studies in yeast and animals have found numerous examples of selective autophagy,with cargo including proteins,protein aggregates,and organelles.Recent work has also provided evidence for several types of selective autophagy in plants.The degradation of protein aggregates was the first selective autophagy described in plants,and,more recently,a hybrid protein of the mammalian selective autophagy adaptors p62 and NBR1,which interacts with the autophagy machinery and may function in autophagy of protein aggregates,was described in plants.Other intracellular components have been suggested to be selectively targeted by autophagy in plants,but the current evidence is limited.Here,we discuss recent findings regarding the selective targeting of cell components by autophagy in plants.

  18. Regulation of autophagy by the inositol trisphosphate receptor.

    Science.gov (United States)

    Criollo, A; Maiuri, M C; Tasdemir, E; Vitale, I; Fiebig, A A; Andrews, D; Molgó, J; Díaz, J; Lavandero, S; Harper, F; Pierron, G; di Stefano, D; Rizzuto, R; Szabadkai, G; Kroemer, G

    2007-05-01

    The reduction of intracellular 1,4,5-inositol trisphosphate (IP(3)) levels stimulates autophagy, whereas the enhancement of IP(3) levels inhibits autophagy induced by nutrient depletion. Here, we show that knockdown of the IP(3) receptor (IP(3)R) with small interfering RNAs and pharmacological IP(3)R blockade is a strong stimulus for the induction of autophagy. The IP(3)R is known to reside in the membranes of the endoplasmic reticulum (ER) as well as within ER-mitochondrial contact sites, and IP(3)R blockade triggered the autophagy of both ER and mitochondria, as exactly observed in starvation-induced autophagy. ER stressors such as tunicamycin and thapsigargin also induced autophagy of ER and, to less extent, of mitochondria. Autophagy triggered by starvation or IP(3)R blockade was inhibited by Bcl-2 and Bcl-X(L) specifically targeted to ER but not Bcl-2 or Bcl-X(L) proteins targeted to mitochondria. In contrast, ER stress-induced autophagy was not inhibited by Bcl-2 and Bcl-X(L). Autophagy promoted by IP(3)R inhibition could not be attributed to a modulation of steady-state Ca(2+) levels in the ER or in the cytosol, yet involved the obligate contribution of Beclin-1, autophagy-related gene (Atg)5, Atg10, Atg12 and hVps34. Altogether, these results strongly suggest that IP(3)R exerts a major role in the physiological control of autophagy.

  19. Emerging role of mammalian autophagy in ketogenesis to overcome starvation.

    Science.gov (United States)

    Takagi, Ayano; Kume, Shinji; Maegawa, Hiroshi; Uzu, Takashi

    2016-01-01

    Autophagy is essential for the survival of lower organisms under conditions of nutrient depletion. However, whether autophagy plays a physiological role in mammals experiencing starvation is unknown. Ketogenesis is critical for overcoming starvation in mammals. We recently revealed that hepatic and renal autophagy are involved in starvation-induced ketogenesis, by utilizing tissue-specific autophagy-deficient mouse models. The liver is the principal organ to regulate ketogenesis, and a deficiency of liver-specific autophagy partially but significantly attenuates starvation-induced ketogenesis. While deficiency of renal-specific autophagy does not affect starvation-induced ketogenesis, mice with deficiency of both liver and kidney autophagy have even lower blood ketone levels and physical activity under starvation conditions than those lacking autophagy in the liver alone. These results suggest that the kidney can compensate for impaired hepatic ketogenesis. Since ketone bodies are catabolized from fatty acids, the uptake of fatty acids, the formation of intracellular lipid droplets, and fatty acid oxidation are critical for ketogenesis. We found that starvation-induced lipid droplet formation is impaired in autophagy-deficient organs. Thus, hepatic and renal autophagy are required for starvation-induced ketogenesis. This process is essential for maintaining systemic energy homeostasis and physical activity during starvation. Our findings provide a novel insight into mammalian autophagy and the physiology of starvation.

  20. Role of the Crosstalk between Autophagy and Apoptosis in Cancer

    Directory of Open Access Journals (Sweden)

    Minfei Su

    2013-01-01

    Full Text Available Autophagy and apoptosis are catabolic pathways essential for organismal homeostasis. Autophagy is normally a cell-survival pathway involving the degradation and recycling of obsolete, damaged, or harmful macromolecular assemblies; however, excess autophagy has been implicated in type II cell death. Apoptosis is the canonical programmed cell death pathway. Autophagy and apoptosis have now been shown to be interconnected by several molecular nodes of crosstalk, enabling the coordinate regulation of degradation by these pathways. Normally, autophagy and apoptosis are both tumor suppressor pathways. Autophagy fulfils this role as it facilitates the degradation of oncogenic molecules, preventing development of cancers, while apoptosis prevents the survival of cancer cells. Consequently, defective or inadequate levels of either autophagy or apoptosis can lead to cancer. However, autophagy appears to have a dual role in cancer, as it has now been shown that autophagy also facilitates the survival of tumor cells in stress conditions such as hypoxic or low-nutrition environments. Here we review the multiple molecular mechanisms of coordination of autophagy and apoptosis and the role of the proteins involved in this crosstalk in cancer. A comprehensive understanding of the interconnectivity of autophagy and apoptosis is essential for the development of effective cancer therapeutics.

  1. Poly-ADP-ribosylation of HMGB1 regulates TNFSF10/TRAIL resistance through autophagy.

    Science.gov (United States)

    Yang, Minghua; Liu, Liying; Xie, Min; Sun, Xiaofang; Yu, Yan; Kang, Rui; Yang, Liangchun; Zhu, Shan; Cao, Lizhi; Tang, Daolin

    2015-01-01

    Both apoptosis ("self-killing") and autophagy ("self-eating") are evolutionarily conserved processes, and their crosstalk influences anticancer drug sensitivity and cell death. However, the underlying mechanism remains unclear. Here, we demonstrated that HMGB1 (high mobility group box 1), normally a nuclear protein, is a crucial regulator of TNFSF10/TRAIL (tumor necrosis factor [ligand] superfamily, member 10)-induced cancer cell death. Activation of PARP1 (poly [ADP-ribose] polymerase 1) was required for TNFSF10-induced ADP-ribosylation of HMGB1 in cancer cells. Moreover, pharmacological inhibition of PARP1 activity or knockdown of PARP1 gene expression significantly inhibited TNFSF10-induced HMGB1 cytoplasmic translocation and subsequent HMGB1-BECN1 complex formation. Furthermore, suppression of the PARP1-HMGB1 pathway diminished autophagy, increased apoptosis, and enhanced the anticancer activity of TNFSF10 in vitro and in a subcutaneous tumor model. These results indicate that PARP1 acts as a prominent upstream regulator of HMGB1-mediated autophagy and maintains a homeostatic balance between apoptosis and autophagy, which provides new insight into the mechanism of TNFSF10 resistance.

  2. Rapamycin induces differentiation of glioma stem/progenitor cells by activating autophagy

    Institute of Scientific and Technical Information of China (English)

    Wen-Zhuo Zhuang; Lin-Mei Long; Wen-Jun Ji; Zhong-Qin Liang

    2011-01-01

    Glioma stem/progenitor cells(GSPCs) are considered to be responsible for the initiation,propagation,and recurrence of gliomas.The factors determining their differentiation remain poorly defined.Accumulating evidences indicate that alterations in autophagy may influence cell fate during mammalian development and differentiation.Here,we investigated the role of autophagy in GSPC differentiation.SU-2 cells were treated with rapamycin,3-methyladenine (3-MA) plus rapamycin,E64d plus rapamycin,or untreated as control.SU-2 cell xenografts in nude mice were treated with rapamycin or 3-MA plus rapamycin,or untreated as control.Western blotting and immunocytochemistry showed up-regulation of microtubule-associated protein light chain-3(LC3)-II in rapamycin-treated cells.The neurosphere formation rate and the number of cells in each neurosphere were significantly lower in the rapamycin treatment group than in other groups.Real-time PCR and immunocytochemistry showed down-regulation of stem/progenitor cell markers and up-regulation of differentiation markers in rapamycin-treated cells.Transmission electron microscopy revealed autophagy activation in rapamycin-treated tumor cells in mice.Immunohistochemistry revealed decreased Nestin-positive cells and increased GFAP-positive cells in rapamycin-treated tumor sections.These results indicate that rapamycin induces differentiation of GSPCs by activating autophagy.

  3. HIV-1 differentially modulates autophagy in neurons and astrocytes.

    Science.gov (United States)

    Mehla, Rajeev; Chauhan, Ashok

    2015-08-15

    Autophagy, a lysosomal degradative pathway that maintains cellular homeostasis, has emerged as an innate immune defense against pathogens. The role of autophagy in the deregulated HIV-infected central nervous system (CNS) is unclear. We have found that HIV-1-induced neuro-glial (neurons and astrocytes) damage involves modulation of the autophagy pathway. Neuro-glial stress induced by HIV-1 led to biochemical and morphological dysfunctions. X4 HIV-1 produced neuro-glial toxicity coupled with suppression of autophagy, while R5 HIV-1-induced toxicity was restricted to neurons. Rapamycin, a specific mTOR inhibitor (autophagy inducer) relieved the blockage of the autophagy pathway caused by HIV-1 and resulted in neuro-glial protection. Further understanding of the regulation of autophagy by cytokines and chemokines or other signaling events may lead to recognition of therapeutic targets for neurodegenerative diseases.

  4. Porcine Epidemic Diarrhea Virus Induces Autophagy to Benefit Its Replication

    Directory of Open Access Journals (Sweden)

    Xiaozhen Guo

    2017-03-01

    Full Text Available The new porcine epidemic diarrhea (PED has caused devastating economic losses to the swine industry worldwide. Despite extensive research on the relationship between autophagy and virus infection, the concrete role of autophagy in porcine epidemic diarrhea virus (PEDV infection has not been reported. In this study, autophagy was demonstrated to be triggered by the effective replication of PEDV through transmission electron microscopy, confocal microscopy, and Western blot analysis. Moreover, autophagy was confirmed to benefit PEDV replication by using autophagy regulators and RNA interference. Furthermore, autophagy might be associated with the expression of inflammatory cytokines and have a positive feedback loop with the NF-κB signaling pathway during PEDV infection. This work is the first attempt to explore the complex interplay between autophagy and PEDV infection. Our findings might accelerate our understanding of the pathogenesis of PEDV infection and provide new insights into the development of effective therapeutic strategies.

  5. Autophagy-associated immune responses and cancer immunotherapy.

    Science.gov (United States)

    Pan, Hongming; Chen, Liuxi; Xu, Yinghua; Han, Weidong; Lou, Fang; Fei, Weiqiang; Liu, Shuiping; Jing, Zhao; Sui, Xinbing

    2016-04-19

    Autophagy is an evolutionarily conserved catabolic process by which cellular components are sequestered into a double-membrane vesicle and delivered to the lysosome for terminal degradation and recycling. Accumulating evidence suggests that autophagy plays a critical role in cell survival, senescence and homeostasis, and its dysregulation is associated with a variety of diseases including cancer, cardiovascular disease, neurodegeneration. Recent studies show that autophagy is also an important regulator of cell immune response. However, the mechanism by which autophagy regulates tumor immune responses remains elusive. In this review, we will describe the role of autophagy in immune regulation and summarize the possible molecular mechanisms that are currently well documented in the ability of autophagy to control cell immune response. In addition, the scientific and clinical hurdles regarding the potential role of autophagy in cancer immunotherapy will be discussed.

  6. Degradation of AF1Q by chaperone-mediated autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Ji, Min; Lu, Fei; Zhang, Jingru [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Li, Huanjie; Cui, Taixing; Li Wang, Xing [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Tang, Dongqi, E-mail: tangdq@sdu.edu.cn [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Center for Stem Cell and Regenerative Medicine, The Second Hospital of Shandong University, Jinan 250033 (China); Ji, Chunyan, E-mail: jichunyan@sdu.edu.cn [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China)

    2014-09-10

    AF1Q, a mixed lineage leukemia gene fusion partner, is identified as a poor prognostic biomarker for pediatric acute myeloid leukemia (AML), adult AML with normal cytogenetic and adult myelodysplastic syndrome. AF1Q is highly regulated during hematopoietic progenitor differentiation and development but its regulatory mechanism has not been defined clearly. In the present study, we used pharmacological and genetic approaches to influence chaperone-mediated autophagy (CMA) and explored the degradation mechanism of AF1Q. Pharmacological inhibitors of lysosomal degradation, such as chloroquine, increased AF1Q levels, whereas activators of CMA, including 6-aminonicotinamide and nutrient starvation, decreased AF1Q levels. AF1Q interacts with HSPA8 and LAMP-2A, which are core components of the CMA machinery. Knockdown of HSPA8 or LAMP-2A increased AF1Q protein levels, whereas overexpression showed the opposite effect. Using an amino acid deletion AF1Q mutation plasmid, we identified that AF1Q had a KFERQ-like motif which was recognized by HSPA8 for CMA-dependent proteolysis. In conclusion, we demonstrate for the first time that AF1Q can be degraded in lysosomes by CMA. - Highlights: • Chaperone-mediated autophagy (CMA) is involved in the degradation of AF1Q. • Macroautophagy does not contribute to the AF1Q degradation. • AF1Q has a KFERQ-like motif that is recognized by CMA core components.

  7. Autophagy in the light of sphingolipid metabolism

    DEFF Research Database (Denmark)

    Harvald, Eva Bang; Olsen, Anne Sofie Braun; Færgeman, Nils J.

    2015-01-01

    , has over the past decade been recognized as an essential part of metabolism. Autophagy not only rids the cell of excessive or damaged organelles, misfolded proteins, and invading microorganisms, it also provides nutrients to maintain crucial cellular functions. Besides serving as essential structural......Maintenance of cellular homeostasis requires tight and coordinated control of numerous metabolic pathways, which are governed by interconnected networks of signaling pathways and energy-sensing regulators. Autophagy, a lysosomal degradation pathway by which the cell self-digests its own components...

  8. Autophagy and proteins involved in vesicular trafficking.

    Science.gov (United States)

    Amaya, Celina; Fader, Claudio Marcelo; Colombo, María Isabel

    2015-11-14

    Autophagy is an intracellular degradation system that, as a basic mechanism it delivers cytoplasmic components to the lysosomes in order to maintain adequate energy levels and cellular homeostasis. This complex cellular process is activated by low cellular nutrient levels and other stress situations such as low ATP levels, the accumulation of damaged proteins or organelles, or pathogen invasion. Autophagy as a multistep process involves vesicular transport events leading to tethering and fusion of autophagic vesicles with several intracellular compartments. This review summarizes our current understanding of the autophagic pathway with emphasis in the trafficking machinery (i.e. Rabs GTPases and SNAP receptors (SNAREs)) involved in specific steps of the pathway.

  9. LC3B is indispensable for selective autophagy of p62 but not basal autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yoko [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Department of Pediatrics, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Sou, Yu-Shin; Kageyama, Shun [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Takahashi, Takao [Department of Pediatrics, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Ueno, Takashi [Division of Proteomics and Biomolecular Science, Center for Biomedical Research Resources, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Tanaka, Keiji [Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Komatsu, Masaaki, E-mail: komatsu-ms@igakuken.or.jp [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Department of Biochemistry, School of Medicine, Niigata University, Niigata 951-8510 (Japan); Ichimura, Yoshinobu, E-mail: ichimura-ys@igakuken.or.jp [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan)

    2014-03-28

    Highlights: • Knockdown of LC3 or GABARAP families did not affect the basal autophagy. • LC3B has a higher affinity for the autophagy-specific substrate, p62, than GABARAPs. • siRNA-mediated knockdown of LC3B, but not that of GABARAPs, resulted in significant accumulation of p62. - Abstract: Autophagy is a unique intracellular protein degradation system accompanied by autophagosome formation. Besides its important role through bulk degradation in supplying nutrients, this system has an ability to degrade certain proteins, organelles, and invading bacteria selectively to maintain cellular homeostasis. In yeasts, Atg8p plays key roles in both autophagosome formation and selective autophagy based on its membrane fusion property and interaction with autophagy adaptors/specific substrates. In contrast to the single Atg8p in yeast, mammals have 6 homologs of Atg8p comprising LC3 and GABARAP families. However, it is not clear these two families have different or similar functions. The aim of this study was to determine the separate roles of LC3 and GABARAP families in basal/constitutive and/or selective autophagy. While the combined knockdown of LC3 and GABARAP families caused a defect in long-lived protein degradation through lysosomes, knockdown of each had no effect on the degradation. Meanwhile, knockdown of LC3B but not GABARAPs resulted in significant accumulation of p62/Sqstm1, one of the selective substrate for autophagy. Our results suggest that while mammalian Atg8 homologs are functionally redundant with regard to autophagosome formation, selective autophagy is regulated by specific Atg8 homologs.

  10. Glomerular endothelial surface layer acts as a barrier against albumin filtration

    NARCIS (Netherlands)

    Dane, M.J.; Berg, B.M. van den; Avramut, M.C.; Faas, F.G.; Vlag, J. van der; Rops, A.L.; Ravelli, R.B.; Koster, B.J.; Zonneveld, A.J. van; Vink, H.; Rabelink, T.J.

    2013-01-01

    Glomerular endothelium is highly fenestrated, and its contribution to glomerular barrier function is the subject of debate. In recent years, a polysaccharide-rich endothelial surface layer (ESL) has been postulated to act as a filtration barrier for large molecules, such as albumin. To test this hyp

  11. Clinical use of estimated glomerular filtration rate for evaluation of kidney function

    DEFF Research Database (Denmark)

    Broberg, Bo; Lindhardt, Morten; Rossing, Peter;

    2013-01-01

    Estimating glomerular filtration rate by the Modification of Diet in Renal Disease or Chronic Kidney Disease Epidemiology Collaboration formulas gives a reasonable estimate of kidney function for e.g. classification of chronic kidney disease. Additionally the estimated glomerular filtration rate...

  12. Conditionally immortalized human glomerular endothelial cells expressing fenestrations in response to VEGF.

    NARCIS (Netherlands)

    Satchell, S.C.; Tasman, C.H.; Singh, A.; Ni, L.; Geelen, J.M.; Ruhland, C.J. von; O'Hare, M.J.; Saleem, M.A.; Heuvel, L.P.W.J. van den; Mathieson, P.W.

    2006-01-01

    Glomerular endothelial cells (GEnC) are specialized cells with important roles in physiological filtration and glomerular disease. Despite their unique features, GEnC have been little studied because of difficulty in maintaining them in cell culture. We have addressed this problem by generation of c

  13. Comparison of glomerular activity patterns by fMRI and wide-field calcium imaging: Implications for principles underlying odor mapping.

    Science.gov (United States)

    Sanganahalli, Basavaraju G; Rebello, Michelle R; Herman, Peter; Papademetris, Xenophon; Shepherd, Gordon M; Verhagen, Justus V; Hyder, Fahmeed

    2016-02-01

    Functional imaging signals arise from distinct metabolic and hemodynamic events at the neuropil, but how these processes are influenced by pre- and post-synaptic activities need to be understood for quantitative interpretation of stimulus-evoked mapping data. The olfactory bulb (OB) glomeruli, spherical neuropil regions with well-defined neuronal circuitry, can provide insights into this issue. Optical calcium-sensitive fluorescent dye imaging (OICa(2+)) reflects dynamics of pre-synaptic input to glomeruli, whereas high-resolution functional magnetic resonance imaging (fMRI) using deoxyhemoglobin contrast reveals neuropil function within the glomerular layer where both pre- and post-synaptic activities contribute. We imaged odor-specific activity patterns of the dorsal OB in the same anesthetized rats with fMRI and OICa(2+) and then co-registered the respective maps to compare patterns in the same space. Maps by each modality were very reproducible as trial-to-trial patterns for a given odor, overlapping by ~80%. Maps evoked by ethyl butyrate and methyl valerate for a given modality overlapped by ~80%, suggesting activation of similar dorsal glomerular networks by these odors. Comparison of maps generated by both methods for a given odor showed ~70% overlap, indicating similar odor-specific maps by each method. These results suggest that odor-specific glomerular patterns by high-resolution fMRI primarily tracks pre-synaptic input to the OB. Thus combining OICa(2+) and fMRI lays the framework for studies of OB processing over a range of spatiotemporal scales, where OICa(2+) can feature the fast dynamics of dorsal glomerular clusters and fMRI can map the entire glomerular sheet in the OB.

  14. Impaired autoregulation of glomerular filtration rate in type 1 (insulin-dependent) diabetic patients with nephropathy

    DEFF Research Database (Denmark)

    Parving, H H; Kastrup, Helge; Smidt, U M;

    1984-01-01

    served as controls. Renal function was assessed by glomerular filtration rate (single bolus 51Cr-EDTA technique) and urinary albumin excretion rate (radial immunodiffusion). The study was performed twice within 2 weeks, with the subjects receiving an intravenous injection of either clonidine (225...... arterial blood pressure in all three groups (16-18 mmHg). While glomerular filtration rate and urinary albumin excretion rate remained unchanged in both control groups after clonidine injection, glomerular filtration rate diminished from 78 to 71 ml/min per 1.73 m2 (p les than 0.01), and urinary albumin...... excretion declined from 1707 to 938 micrograms/min (p less than 0.01) in the patients with diabetic nephropathy. Our results suggest that an intrinsic vascular (arteriolar) mechanism underlying the normal autoregulation of glomerular filtration rate, i.e. the relative constancy of glomerular filtration rate...

  15. Autophagy controls BCG-induced trained immunity and the response to intravesical BCG therapy for bladder cancer.

    Directory of Open Access Journals (Sweden)

    Kathrin Buffen

    2014-10-01

    Full Text Available The anti-tuberculosis-vaccine Bacillus Calmette-Guérin (BCG is the most widely used vaccine in the world. In addition to its effects against tuberculosis, BCG vaccination also induces non-specific beneficial effects against certain forms of malignancy and against infections with unrelated pathogens. It has been recently proposed that the non-specific effects of BCG are mediated through epigenetic reprogramming of monocytes, a process called trained immunity. In the present study we demonstrate that autophagy contributes to trained immunity induced by BCG. Pharmacologic inhibition of autophagy blocked trained immunity induced in vitro by stimuli such as β-glucans or BCG. Single nucleotide polymorphisms (SNPs in the autophagy genes ATG2B (rs3759601 and ATG5 (rs2245214 influenced both the in vitro and in vivo training effect of BCG upon restimulation with unrelated bacterial or fungal stimuli. Furthermore, pharmacologic or genetic inhibition of autophagy blocked epigenetic reprogramming of monocytes at the level of H3K4 trimethylation. Finally, we demonstrate that rs3759601 in ATG2B correlates with progression and recurrence of bladder cancer after BCG intravesical instillation therapy. These findings identify a key role of autophagy for the nonspecific protective effects of BCG.

  16. GADD45A inhibits autophagy by regulating the interaction between BECN1 and PIK3C3.

    Science.gov (United States)

    Zhang, Dongdong; Zhang, Weimin; Li, Dan; Fu, Ming; Chen, Runsheng; Zhan, Qimin

    2015-01-01

    GADD45A is a TP53-regulated and DNA damage-inducible tumor suppressor protein, which regulates cell cycle arrest, apoptosis, and DNA repair, and inhibits tumor growth and angiogenesis. However, the function of GADD45A in autophagy remains unknown. In this report, we demonstrate that GADD45A plays an important role in regulating the process of autophagy. GADD45A is able to decrease LC3-II expression and numbers of autophagosomes in mouse tissues and different cancer cell lines. Using bafilomycin A1 treatment, we have observed that GADD45A regulates autophagosome initiation. Likely, GADD45A inhibition of autophagy is through its influence on the interaction between BECN1 and PIK3C3. Immunoprecipitation and GST affinity isolation assays exhibit that GADD45A directly interacts with BECN1, and in turn dissociates the BECN1-PIK3C3 complex. Furthermore, we have mapped the 71 to 81 amino acids of the GADD45A protein that are necessary for the GADD45A interaction with BECN1. Knockdown of BECN1 can abolish autophagy alterations induced by GADD45A. Taken together, these findings provide the novel evidence that GADD45A inhibits autophagy via impairing the BECN1-PIK3C3 complex formation.

  17. Glomerular Diseases Associated with Hepatitis C Virus Infection

    Directory of Open Access Journals (Sweden)

    Miller Sara

    2000-01-01

    Full Text Available Renal diseases associated with hepatitis C virus (HCV infection are a significant problem for clinicians and diagnostic pathologists. A wide variety of disorders, including a spectrum of immune-complex glomerulonephritides, has been reported in association with hepatitis and cirrhosis caused by HCV. For some of these diseases, including membranoproliferative glomerulonephritis type I and cryoglobulinemic glomerulonephritis, plausible links between HCV and the glomerular pathology have been proposed. In other cases, the role of the virus in the pathogenesis of the renal disease is less certain. This communication catalogues the renal manifestations of HCV infection, providing clinical and pathological descriptions of the most prevalent disorders. Where available, evidence implicating HCV in the causation of the disorders is also discussed.

  18. Glomerular filtration rate in cows estimated by a prediction formula.

    Science.gov (United States)

    Murayama, Isao; Miyano, Anna; Sato, Tsubasa; Iwama, Ryosuke; Satoh, Hiroshi; Ichijyo, Toshihiro; Sato, Shigeru; Furuhama, Kazuhisa

    2014-12-01

    To testify the relevance of Jacobsson's equation for estimating bovine glomerular filtration rate (GFR), we prepared an integrated formula based on its equation using clinically healthy dairy (n=99) and beef (n=63) cows, and cows with reduced renal function (n=15). The isotonic, nonionic, contrast medium iodixanol was utilized as a test tracer. The GFR values estimated from the integrated formula were well consistent with those from the standard multisample method in each cow strain, and the Holstein equation prepared by a single blood sample in Holstein dairy cows. The basal reference GFR value in healthy dairy cows was significantly higher than that in healthy beef cows, presumably due to a breed difference or physiological state difference. It is concluded that the validity for the application of Jacobsson's equation to estimate bovine GFR is proven and it can be used in bovine practices.

  19. B Cell Depletion: Rituximab in Glomerular Disease and Transplantation

    Directory of Open Access Journals (Sweden)

    S. Marinaki

    2013-12-01

    Full Text Available B cells play a central role in the pathogenesis of many autoimmune diseases. Selective targeting can be achieved with the use of the monoclonal antibody rituximab. In addition to being a drug for non-Hodgkin's lymphoma, rituximab is also an FDA-approved treatment for refractory rheumatoid arthritis and, since recently, ANCA vasculitis. It has shown efficacy in many autoimmune diseases. This review will discuss current evidence and the rationale of the use of rituximab in glomerular diseases, including randomized controlled trials. The focus will be on the use of rituximab in idiopathic membranous nephropathy, systemic lupus erythematosus and ANCA-associated vasculitis. The emerging role of rituximab in renal transplantation, where it seems to be important for the desensitization protocols for highly sensitized patients as well as for the preconditioning of ABO-incompatible recipients and the treatment of antibody-mediated rejection, will also be addressed.

  20. Trehalose Accumulation Triggers Autophagy during Plant Desiccation.

    Directory of Open Access Journals (Sweden)

    Brett Williams

    2015-12-01

    Full Text Available Global climate change, increasingly erratic weather and a burgeoning global population are significant threats to the sustainability of future crop production. There is an urgent need for the development of robust measures that enable crops to withstand the uncertainty of climate change whilst still producing maximum yields. Resurrection plants possess the unique ability to withstand desiccation for prolonged periods, can be restored upon watering and represent great potential for the development of stress tolerant crops. Here, we describe the remarkable stress characteristics of Tripogon loliiformis, an uncharacterised resurrection grass and close relative of the economically important cereals, rice, sorghum, and maize. We show that T. loliiformis survives extreme environmental stress by implementing autophagy to prevent Programmed Cell Death. Notably, we identified a novel role for trehalose in the regulation of autophagy in T.loliiformis. Transcriptome, Gas Chromatography Mass Spectrometry, immunoblotting and confocal microscopy analyses directly linked the accumulation of trehalose with the onset of autophagy in dehydrating and desiccated T. loliiformis shoots. These results were supported in vitro with the observation of autophagosomes in trehalose treated T. loliiformis leaves; autophagosomes were not detected in untreated samples. Presumably, once induced, autophagy promotes desiccation tolerance in T.loliiformis, by removal of cellular toxins to suppress programmed cell death and the recycling of nutrients to delay the onset of senescence. These findings illustrate how resurrection plants manipulate sugar metabolism to promote desiccation tolerance and may provide candidate genes that are potentially useful for the development of stress tolerant crops.

  1. Avermectin induced autophagy in pigeon spleen tissues.

    Science.gov (United States)

    Liu, Ci; Zhao, Yanbing; Chen, Lijie; Zhang, Ziwei; Li, Ming; Li, Shu

    2015-12-05

    The level of autophagy is considered as an indicator for monitoring the toxic impact of pesticide exposure. Avermectin (AVM), a widely used insecticide, has immunotoxic effects on the pigeon spleen. The aim of this study was to investigate the status of autophagy and the expression levels of microtubule-associated protein1 light chain 3 (LC3), beclin-1, dynein, autophagy associated gene (Atg) 4B, Atg5, target of rapamycin complex 1 (TORC1) and target of rapamycin complex 2 (TORC2) in AVM-treated pigeon spleens. Eighty two-month-old pigeons were randomly divided into four groups: a control group, a low-dose group, a medium-dose group and a high-dose group, which were fed a basal diet spiked with 0, 20, 40 and 60 mg AVM/kg diet, respectively. Microscopic cellular morphology revealed a significant increase in autophagic structures in the AVM-treated groups. The expression of LC3, beclin-1, dynein, Atg4B and Atg5 increased, while mRNA levels of TORC1 and TORC2 were decreased in the AVM-treated groups relative to the control groups at 30, 60 and 90 days in the pigeon spleen. These results indicated that AVM exposure could up-regulate the level of autophagy in a dose-time-dependent manner in the pigeon spleen.

  2. Autophagy-mediated clearance of aggresomes is not a universal phenomenon

    OpenAIRE

    2008-01-01

    Aggresomes are juxtanuclear inclusion bodies that have been proposed to act as staging grounds for the disposal of protein aggregates via the autophagic route. To examine whether the composition of an aggresome influences its clearance by autophagy, we ectopically expressed a variety of aggregation-prone proteins in cultured cells to generate aggresomes that differ in their protein content. We found that whereas aggresomes generated in cells expressing mutant huntingtin or mutant tau, or co-e...

  3. Spermidine and resveratrol induce autophagy by distinct pathways converging on the acetylproteome

    DEFF Research Database (Denmark)

    Morselli, Eugenia; Mariño, Guillermo; Bennetzen, Martin V

    2011-01-01

    Autophagy protects organelles, cells, and organisms against several stress conditions. Induction of autophagy by resveratrol requires the nicotinamide adenine dinucleotide-dependent deacetylase sirtuin 1 (SIRT1). In this paper, we show that the acetylase inhibitor spermidine stimulates autophagy ...

  4. Mutant p53 protein localized in the cytoplasm inhibits autophagy.

    Science.gov (United States)

    Morselli, Eugenia; Tasdemir, Ezgi; Maiuri, Maria Chiara; Galluzzi, Lorenzo; Kepp, Oliver; Criollo, Alfredo; Vicencio, José Miguel; Soussi, Thierry; Kroemer, Guido

    2008-10-01

    The knockout, knockdown or chemical inhibition of p53 stimulates autophagy. Moreover, autophagy-inducing stimuli such as nutrient depletion, rapamycin or lithium cause the depletion of cytoplasmic p53, which in turn is required for the induction of autophagy. Here, we show that retransfection of p53(-/-) HCT 116 colon carcinoma cells with wild type p53 decreases autophagy down to baseline levels. Surprisingly, one third among a panel of 22 cancer-associated p53 single amino acid mutants also inhibited autophagy when transfected into p53(-/-) cells. Those variants of p53 that preferentially localize to the cytoplasm effectively repressed autophagy, whereas p53 mutants that display a prominently nuclear distribution failed to inhibit autophagy. The investigation of a series of deletion mutants revealed that removal of the DNA-binding domain from p53 fails to interfere with its role in the regulation of autophagy. Altogether, these results identify the cytoplasmic localization of p53 as the most important feature for p53-mediated autophagy inhibition. Moreover, the structural requirements for the two biological activities of extranuclear p53, namely induction of apoptosis and inhibition of autophagy, are manifestly different.

  5. Autophagy modulates articular cartilage vesicle formation in primary articular chondrocytes.

    Science.gov (United States)

    Rosenthal, Ann K; Gohr, Claudia M; Mitton-Fitzgerald, Elizabeth; Grewal, Rupinder; Ninomiya, James; Coyne, Carolyn B; Jackson, William T

    2015-05-22

    Chondrocyte-derived extracellular organelles known as articular cartilage vesicles (ACVs) participate in non-classical protein secretion, intercellular communication, and pathologic calcification. Factors affecting ACV formation and release remain poorly characterized; although in some cell types, the generation of extracellular vesicles is associated with up-regulation of autophagy. We sought to determine the role of autophagy in ACV production by primary articular chondrocytes. Using an innovative dynamic model with a light scatter nanoparticle counting apparatus, we determined the effects of autophagy modulators on ACV number and content in conditioned medium from normal adult porcine and human osteoarthritic chondrocytes. Healthy articular chondrocytes release ACVs into conditioned medium and show significant levels of ongoing autophagy. Rapamycin, which promotes autophagy, increased ACV numbers in a dose- and time-dependent manner associated with increased levels of autophagy markers and autophagosome formation. These effects were suppressed by pharmacologic autophagy inhibitors and short interfering RNA for ATG5. Caspase-3 inhibition and a Rho/ROCK inhibitor prevented rapamycin-induced increases in ACV number. Osteoarthritic chondrocytes, which are deficient in autophagy, did not increase ACV number in response to rapamycin. SMER28, which induces autophagy via an mTOR-independent mechanism, also increased ACV number. ACVs induced under all conditions had similar ecto-enzyme specific activities and types of RNA, and all ACVs contained LC3, an autophagosome-resident protein. These findings identify autophagy as a critical participant in ACV formation, and augment our understanding of ACVs in cartilage disease and repair.

  6. Crosstalk of clock gene expression and autophagy in aging

    Science.gov (United States)

    Kalfalah, Faiza; Janke, Linda; Schiavi, Alfonso; Tigges, Julia; Ix, Alexander; Ventura, Natascia; Boege, Fritz; Reinke, Hans

    2016-01-01

    Autophagy and the circadian clock counteract tissue degeneration and support longevity in many organisms. Accumulating evidence indicates that aging compromises both the circadian clock and autophagy but the mechanisms involved are unknown. Here we show that the expression levels of transcriptional repressor components of the circadian oscillator, most prominently the human Period homologue PER2, are strongly reduced in primary dermal fibroblasts from aged humans, while raising the expression of PER2 in the same cells partially restores diminished autophagy levels. The link between clock gene expression and autophagy is corroborated by the finding that the circadian clock drives cell-autonomous, rhythmic autophagy levels in immortalized murine fibroblasts, and that siRNA-mediated downregulation of PER2 decreases autophagy levels while leaving core clock oscillations intact. Moreover, the Period homologue lin-42 regulates autophagy and life span in the nematode Caenorhabditis elegans, suggesting an evolutionarily conserved role for Period proteins in autophagy control and aging. Taken together, this study identifies circadian clock proteins as set-point regulators of autophagy and puts forward a model, in which age-related changes of clock gene expression promote declining autophagy levels. PMID:27574892

  7. Induction of cytoprotective autophagy in PC-12 cells by cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiwen [College of Veterinary Medicine, Yangzhou University, Yangzhou 225009 (China); Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009 (China); Bijie Pilot Area Research Institute of Bijie University, Bijie 551700 (China); Zhu, Jiaqiao; Zhang, Kangbao; Jiang, Chenyang; Wang, Yi; Yuan, Yan; Bian, Jianchun; Liu, Xuezhong; Gu, Jianhong [College of Veterinary Medicine, Yangzhou University, Yangzhou 225009 (China); Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009 (China); Liu, Zongping, E-mail: liuzongping@yzu.edu.cn [College of Veterinary Medicine, Yangzhou University, Yangzhou 225009 (China); Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009 (China)

    2013-08-16

    Highlights: •Cadmium can promote early upregulation of autophagy in PC-12 cells. •Autophagy precedes apoptosis in cadmium-treated PC-12 cells. •Cadmium-induced autophagy is cytoprotective in PC-12 cells. •Class III PI3K/beclin-1/Bcl-2 signaling pathway plays a positive role in cadmium-triggered autophagy. -- Abstract: Laboratory data have demonstrated that cadmium (Cd) may induce neuronal apoptosis. However, little is known about the role of autophagy in neurons. In this study, cell viability decreased in a dose- and time-dependent manner after treatment with Cd in PC-12 cells. As cells were exposed to Cd, the levels of LC3-II proteins became elevated, specific punctate distribution of endogenous LC3-II increased, and numerous autophagosomes appeared, which suggest that Cd induced a high level of autophagy. In the late stages of autophagy, an increase in the apoptosis ratio was observed. Likewise, pre-treatment with chloroquine (an autophagic inhibitor) and rapamycin (an autophagic inducer) resulted in an increased and decreased percentage of apoptosis in contrast to other Cd-treated groups, respectively. The results indicate that autophagy delayed apoptosis in Cd-treated PC-12 cells. Furthermore, co-treatment of cells with chloroquine reduced autophagy and cell activity. However, rapamycin had an opposite effect on autophagy and cell activity. Moreover, class III PI3 K/beclin-1/Bcl-2 signaling pathways served a function in Cd-induced autophagy. The findings suggest that Cd can induce cytoprotective autophagy by activating class III PI3 K/beclin-1/Bcl-2 signaling pathways. In sum, this study strongly suggests that autophagy may serve a positive function in the reduction of Cd-induced cytotoxicity.

  8. Autophagy-related prognostic signature for breast cancer.

    Science.gov (United States)

    Gu, Yunyan; Li, Pengfei; Peng, Fuduan; Zhang, Mengmeng; Zhang, Yuanyuan; Liang, Haihai; Zhao, Wenyuan; Qi, Lishuang; Wang, Hongwei; Wang, Chenguang; Guo, Zheng

    2016-03-01

    Autophagy is a process that degrades intracellular constituents, such as long-lived or damaged proteins and organelles, to buffer metabolic stress under starvation conditions. Deregulation of autophagy is involved in the progression of cancer. However, the predictive value of autophagy for breast cancer prognosis remains unclear. First, based on gene expression profiling, we found that autophagy genes were implicated in breast cancer. Then, using the Cox proportional hazard regression model, we detected autophagy prognostic signature for breast cancer in a training dataset. We identified a set of eight autophagy genes (BCL2, BIRC5, EIF4EBP1, ERO1L, FOS, GAPDH, ITPR1 and VEGFA) that were significantly associated with overall survival in breast cancer. The eight autophagy genes were assigned as a autophagy-related prognostic signature for breast cancer. Based on the autophagy-related signature, the training dataset GSE21653 could be classified into high-risk and low-risk subgroups with significantly different survival times (HR = 2.72, 95% CI = (1.91, 3.87); P = 1.37 × 10(-5)). Inactivation of autophagy was associated with shortened survival of breast cancer patients. The prognostic value of the autophagy-related signature was confirmed in the testing dataset GSE3494 (HR = 2.12, 95% CI = (1.48, 3.03); P = 1.65 × 10(-3)) and GSE7390 (HR = 1.76, 95% CI = (1.22, 2.54); P = 9.95 × 10(-4)). Further analysis revealed that the prognostic value of the autophagy signature was independent of known clinical prognostic factors, including age, tumor size, grade, estrogen receptor status, progesterone receptor status, ERBB2 status, lymph node status and TP53 mutation status. Finally, we demonstrated that the autophagy signature could also predict distant metastasis-free survival for breast cancer.

  9. Autophagy facilitates Salmonella replication in HeLa cells.

    Science.gov (United States)

    Yu, Hong B; Croxen, Matthew A; Marchiando, Amanda M; Ferreira, Rosana B R; Cadwell, Ken; Foster, Leonard J; Finlay, B Brett

    2014-03-11

    Autophagy is a process whereby a double-membrane structure (autophagosome) engulfs unnecessary cytosolic proteins, organelles, and invading pathogens and delivers them to the lysosome for degradation. We examined the fate of cytosolic Salmonella targeted by autophagy and found that autophagy-targeted Salmonella present in the cytosol of HeLa cells correlates with intracellular bacterial replication. Real-time analyses revealed that a subset of cytosolic Salmonella extensively associates with autophagy components p62 and/or LC3 and replicates quickly, whereas intravacuolar Salmonella shows no or very limited association with p62 or LC3 and replicates much more slowly. Replication of cytosolic Salmonella in HeLa cells is significantly decreased when autophagy components are depleted. Eventually, hyperreplication of cytosolic Salmonella potentiates cell detachment, facilitating the dissemination of Salmonella to neighboring cells. We propose that Salmonella benefits from autophagy for its cytosolic replication in HeLa cells. IMPORTANCE As a host defense system, autophagy is known to target a population of Salmonella for degradation and hence restricting Salmonella replication. In contrast to this concept, a recent report showed that knockdown of Rab1, a GTPase required for autophagy of Salmonella, decreases Salmonella replication in HeLa cells. Here, we have reexamined the fate of Salmonella targeted by autophagy by various cell biology-based assays. We found that the association of autophagy components with cytosolic Salmonella increases shortly after initiation of intracellular bacterial replication. Furthermore, through a live-cell imaging method, a subset of cytosolic Salmonella was found to be extensively associated with autophagy components p62 and/or LC3, and they replicated quickly. Most importantly, depletion of autophagy components significantly reduced the replication of cytosolic Salmonella in HeLa cells. Hence, in contrast to previous reports, we propose

  10. Glomerular lesions in HIV-infected patients: a Yale University Department of Medicine Residency Peer-Teaching Conference.

    OpenAIRE

    1997-01-01

    HIV-associated nephropathy (HIVAN) is a clinicopathologic entity characterized by heavy proteinuria, absence of edema and an irreversible decline in renal function. Findings on renal biopsy include: collapsed glomerular capillaries; visceral glomerular epitheliosis; microcystic tubules; mesangial prominence; and endothelial tubuloreticular inclusions. Early in the AIDS epidemic, HIVAN was the predominant glomerular lesion observed in HIV-infected patients. It is being increasingly recognized,...

  11. Recurrent glomerular disease after kidney transplantation: an update of selected areas and the impact of protocol biopsy.

    Science.gov (United States)

    Morozumi, Kunio; Takeda, Asami; Otsuka, Yasuhiro; Horike, Keiji; Gotoh, Norihiko; Watarai, Yoshihiko

    2014-06-01

    Recurrence of native kidney disease following kidney transplantation affects between 10% and 20% of patients, and accounts for up to 8% of graft failures. In a considerable number of recipients with transplant glomerulopathy, it is impossible to distinguish between recurrent and de novo types. An accurate estimate of the incidence of recurrence is difficult due to limitations in the diagnosis of recurrent glomerulonephritis. De novo glomerular lesions may be misclassified if histological confirmation of the patient's native kidney disease is lacking. Asymptomatic histological recurrence in renal allografts may be missed if protocol biopsies are not available. Studies based on protocol biopsy are pivotal to accurately estimate the incidence of recurrence. Many factors are known to influence recurrence of kidney disease after transplantation, including the type and severity of the original disease, age at onset, interval from onset to end-stage renal disease, and clinical course of the previous transplantation. Early recognition of recurrence is possible in several glomerular diseases. Factors such as the existence of circulating permeability factors, circulating urokinase receptor and anti-phospholipase A2 receptor antibody, as well as disorders of complement regulatory proteins like factor I mutation and factor H mutation factors are expected to be useful predictors of recurrence. Peculiar clinical course of atypical haemolytic uremic syndrome after kidney transplantation is an informative sign of recurrent glomerular disease. These factors play pivotal roles in the development of recurrence of certain types of glomerulopathies. Understanding the pathogenesis of recurrent glomerulonephritis is critical to optimize prevention as well as treat individual cases of recurrent glomerulonephritis. Subclinical recurrence of IgA nephropathy after kidney transplantation is well recognized. Only protocol biopsies of clinically silent recipient can provide the accurate

  12. Autophagy - Adaptive Molecular Mechanisms in Condition of Starvation

    Directory of Open Access Journals (Sweden)

    Pedrycz Agnieszka

    2015-09-01

    Full Text Available Autophagy is an extremely old process during which long-lived proteins and cellular organelles are removed by means of lysosomes. Autophagy may be caused by cellular stress mechanisms. Research has proven that autophagy plays a key role in obtaining nutrients and adapting to the conditions of starvation. Owing to this, it takes part in maintaining homeostasis in cytoplasm and cell nucleus. This objective may be achieved through a number of ways. Depending on the manner in which a substrate connects with the lysosome, we can talk about macroautophagy and microautophagy. Additionally, some authors also distinguish a chaperone-mediated autophagy. The article presented below describes molecular mechanisms of each type of autophagy and focuses particularly on macroautophagy, which is the best understood of all the autophagy types.

  13. Autophagy as a Therapeutic Target in Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Yuki Tanaka

    2012-01-01

    Full Text Available Diabetic nephropathy is a serious complication of diabetes mellitus, and its prevalence has been increasing worldwide. Therefore, there is an urgent need to identify a new therapeutic target to prevent diabetic nephropathy. Autophagy is a major catabolic pathway involved in degrading and recycling macromolecules and damaged organelles to maintain intracellular homeostasis. The study of autophagy in mammalian systems is advancing rapidly and has revealed that it is involved in the pathogenesis of various metabolic or age-related diseases. The functional role of autophagy in the kidneys is also currently under intense investigation although, until recently, evidence showing the involvement of autophagy in the pathogenesis of diabetic nephropathy has been limited. We provide a systematic review of autophagy and discuss the therapeutic potential of autophagy in diabetic nephropathy to help future investigations in this field.

  14. Suppression of autophagy exacerbates Mefloquine-mediated cell death.

    Science.gov (United States)

    Shin, Ji Hyun; Park, So Jung; Jo, Yoon Kyung; Kim, Eun Sung; Kang, Hee; Park, Ji-Ho; Lee, Eunjoo H; Cho, Dong-Hyung

    2012-05-02

    Mefloquine is an effective treatment drug for malaria. However, it can cause several adverse side effects, and the precise mechanism associated with the adverse neurological effects of Mefloquine is not clearly understood. In this study, we investigated the effect of Mefloquine on autophagy in neuroblastoma cells. Mefloquine treatment highly induced the formation of autophagosomes and the conversion of LC3I into LC3II. Moreover, Mefloquine-induced autophagy was efficiently suppressed by an autophagy inhibitor and by down regulation of ATG6. The autophagy was also completely blocked in ATG5 deficient mouse embryonic fibroblast cells. Moreover, suppression of autophagy significantly intensified Mefloquine-mediated cytotoxicity in SH-SY5Y cells. Our findings suggest that suppression of autophagy may exacerbate Mefloquine toxicity in neuroblastoma cells.

  15. Epigenetic modifications as regulatory elements of autophagy in cancer.

    Science.gov (United States)

    Sui, Xinbing; Zhu, Jing; Zhou, Jichun; Wang, Xian; Li, Da; Han, Weidong; Fang, Yong; Pan, Hongming

    2015-05-01

    Epigenetic modifications have been considered as hallmarks of cancer and play an important role in tumor initiation and development. Epigenetic mechanisms, including DNA methylation, histone modifications, and microRNAs, may regulate cell cycle and apoptosis, as well as macroautophagy (hereafter referred to as autophagy). Autophagy, as a crucial cellular homeostatic mechanism, performs a dual role, having pro-survival or pro-death properties. A variety of signaling pathways including epigenetic control have been implicated in the upregulation or downregulation of autophagy. However, the role of epigenetic regulation in autophagy is still less well acknowledged. Recent studies have linked epigenetic control to the autophagic process. Some epigenetic modifiers are also involved in the regulation of autophagy and potentiate the efficacy of traditional therapeutics. Thus, understanding the novel functions of epigenetic control in autophagy may allow us to develop potential therapeutic approaches for cancer treatment.

  16. Research Progression of Cellular Autophagy in Liver System Diseases

    Directory of Open Access Journals (Sweden)

    Chunyun Liu

    2013-09-01

    Full Text Available Autophagy is a basic biological phenomenon widely existed in eukaryotic cells and an important mechanism for cells to adjust to the surrounding environment, prevent invasion of pathogenic micro-organisms and maintain homeostasis, whose activity changes evidently in multiple liver system diseases, suggesting that there is close association between autophagy and the generation and development of liver system diseases. It is also reported that autophagy develops and exerts an important function in many liver-related diseases, such as hepatic carcinoma, non-alcoholic fatty liver disease, alcoholic liver disease, viral liver disease and acute liver injury. Therefore, this study aimed to summarize the relationship between autophagy and multiple liver diseases, hoping to explore the effect of autophagy in liver system diseases and further study the regulative effect of autophagy so as to provide new thoughts for their treatment.

  17. Forms, Crosstalks, and the Role of Phospholipid Biosynthesis in Autophagy

    Directory of Open Access Journals (Sweden)

    Leanne Pereira

    2012-01-01

    Full Text Available Autophagy is a highly conserved cellular process occurring during periods of stress to ensure a cell's survival by recycling cytosolic constituents and making products that can be used in energy generation and other essential processes. Three major forms of autophagy exist according to the specific mechanism through which cytoplasmic material is transported to a lysosome. Chaperone-mediated autophagy is a highly selective form of autophagy that delivers specific proteins for lysosomal degradation. Microautophagy is a less selective form of autophagy that occurs through lysosomal membrane invaginations, forming tubes and directly engulfing cytoplasm. Finally, macroautophagy involves formation of new membrane bilayers (autophagosomes that engulf cytosolic material and deliver it to lysosomes. This review provides new insights on the crosstalks between different forms of autophagy and the significance of bilayer-forming phospholipid synthesis in autophagosomal membrane formation.

  18. Methods for assessing autophagy and autophagic cell death.

    Science.gov (United States)

    Tasdemir, Ezgi; Galluzzi, Lorenzo; Maiuri, M Chiara; Criollo, Alfredo; Vitale, Ilio; Hangen, Emilie; Modjtahedi, Nazanine; Kroemer, Guido

    2008-01-01

    Autophagic (or type 2) cell death is characterized by the massive accumulation of autophagic vacuoles (autophagosomes) in the cytoplasm of cells that lack signs of apoptosis (type 1 cell death). Here we detail and critically assess a series of methods to promote and inhibit autophagy via pharmacological and genetic manipulations. We also review the techniques currently available to detect autophagy, including transmission electron microscopy, half-life assessments of long-lived proteins, detection of LC3 maturation/aggregation, fluorescence microscopy, and colocalization of mitochondrion- or endoplasmic reticulum-specific markers with lysosomal proteins. Massive autophagic vacuolization may cause cellular stress and represent a frustrated attempt of adaptation. In this case, cell death occurs with (or in spite of) autophagy. When cell death occurs through autophagy, on the contrary, the inhibition of the autophagic process should prevent cellular demise. Accordingly, we describe a strategy for discriminating cell death with autophagy from cell death through autophagy.

  19. Research Progression of Cellular Autophagy in Liver System Diseases

    Institute of Scientific and Technical Information of China (English)

    Liu Chunyun; Gong Xiangwen; Xiao Xinfa; Yuan Xiangying

    2013-01-01

    Autophagy is a basic biological phenomenon widely existed in eukaryotic cells and an important mechanism for cells to adjust to the surrounding environment, prevent invasion of pathogenic micro-organisms and maintain homeostasis, whose activity changes evidently in multiple liver system diseases, suggesting that there is close association between autophagy and the generation and development of liver system diseases. It is also reported that autophagy develops and exerts an important function in many liver-related diseases, such as hepatic carcinoma, non-alcoholic fatty liver disease, alcoholic liver disease, viral liver disease and acute liver injury. Therefore, this study aimed to summarize the relationship between autophagy and multiple liver diseases, hoping to explore the effect of autophagy in liver system diseases and further study the regulative effect of autophagy so as to provide new thoughts for their treatment.

  20. Autophagy modulation as a target for anticancer drug discovery

    Institute of Scientific and Technical Information of China (English)

    Xin LI; Huai-long XU; Yong-xi LIU; Na AN; Si ZHAO; Jin-ku BAO

    2013-01-01

    Autophagy,an evolutionarily conserved catabolic process involving the engulfment and degradation of non-essential or abnormal cellular organelles and proteins,is crucial for homeostatic maintenance in living cells.This highly regulated,multi-step process has been implicated in diverse diseases including cancer.Autophagy can function as either a promoter or a suppressor of cancer,which makes it a promising and challenging therapeutic target.Herein,we overview the regulatory mechanisms and dual roles of autophagy in cancer.We also describe some of the representative agents that exert their anticancer effects by regulating autophagy.Additionally,some emerging strategies aimed at modulating autophagy are discussed as having the potential for future anticancer drug discovery.In summary,these findings will provide valuable information to better utilize autophagy in the future development of anticancer therapeutics that meet clinical requirements.

  1. Effects of nifedipine and enalapril on glomerular injury in rats with deoxycorticosterone-salt hypertension.

    Science.gov (United States)

    Dworkin, L D; Levin, R I; Benstein, J A; Parker, M; Ullian, M E; Kim, Y; Feiner, H D

    1990-10-01

    Male Munich-Wistar rats underwent right nephrectomy and were given weekly injections of deoxycorticosterone acetate (DOCA) and 1% saline (salt) to drink. Two studies were performed. In the first, rats given enalapril (ENP) were compared with controls. In the second, rats ingested either standard chow or chow to which the calcium-entry blocker nifedipine (NIF) had been added. Six to eight weeks after nephrectomy, both control DOCA-salt rats and those given ENP had severe hypertension and significant proteinuria. Rats given NIF excreted less protein, and glomerular lesions were not observed in this group. The effects of NIF on several parameters that have been associated with glomerular injury were examined. Micropuncture studies revealed that glomerular capillary pressure was increased in DOCA-salt rats and was not reduced by NIF. Platelet aggregation was also similar in NIF-treated and control rats. Morphometric studies revealed a tendency toward lower glomerular volume of NIF-treated rats; however, kidney weight and glomerular capillary radius were unaffected by therapy. Thus NIF, but not ENP, prevents DOCA-salt rats from developing hypertension and glomerular injury. This effect does not depend on reduction in glomerular pressure or inhibition of platelet aggregation.

  2. Glomerular endothelial surface layer acts as a barrier against albumin filtration.

    Science.gov (United States)

    Dane, Martijn J C; van den Berg, Bernard M; Avramut, M Cristina; Faas, Frank G A; van der Vlag, Johan; Rops, Angelique L W M M; Ravelli, Raimond B G; Koster, Bram J; van Zonneveld, Anton Jan; Vink, Hans; Rabelink, Ton J

    2013-05-01

    Glomerular endothelium is highly fenestrated, and its contribution to glomerular barrier function is the subject of debate. In recent years, a polysaccharide-rich endothelial surface layer (ESL) has been postulated to act as a filtration barrier for large molecules, such as albumin. To test this hypothesis, we disturbed the ESL in C57Bl/6 mice using long-term hyaluronidase infusion for 4 weeks and monitored albumin passage using immunolabeling and correlative light-electron microscopy that allows for complete and integral assessment of glomerular albumin passage. ESL ultrastructure was visualized by transmission electron microscopy using cupromeronic blue and by localization of ESL binding lectins using confocal microscopy. We demonstrate that glomerular fenestrae are filled with dense negatively charged polysaccharide structures that are largely removed in the presence of circulating hyaluronidase, leaving the polysaccharide surfaces of other glomerular cells intact. Both retention of native ferritin [corrected] in the glomerular basement membrane and systemic blood pressure were unaltered. Enzyme treatment, however, induced albumin passage across the endothelium in 90% of glomeruli, whereas this could not be observed in controls. Yet, there was no net albuminuria due to binding and uptake of filtered albumin by the podocytes and parietal epithelium. ESL structure and function completely recovered within 4 weeks on cessation of hyaluronidase infusion. Thus, the polyanionic ESL component, hyaluronan, is a key component of the glomerular endothelial protein permeability barrier.

  3. Genetic Background is a Key Determinant of Glomerular Extracellular Matrix Composition and Organization.

    Science.gov (United States)

    Randles, Michael J; Woolf, Adrian S; Huang, Jennifer L; Byron, Adam; Humphries, Jonathan D; Price, Karen L; Kolatsi-Joannou, Maria; Collinson, Sophie; Denny, Thomas; Knight, David; Mironov, Aleksandr; Starborg, Toby; Korstanje, Ron; Humphries, Martin J; Long, David A; Lennon, Rachel

    2015-12-01

    Glomerular disease often features altered histologic patterns of extracellular matrix (ECM). Despite this, the potential complexities of the glomerular ECM in both health and disease are poorly understood. To explore whether genetic background and sex determine glomerular ECM composition, we investigated two mouse strains, FVB and B6, using RNA microarrays of isolated glomeruli combined with proteomic glomerular ECM analyses. These studies, undertaken in healthy young adult animals, revealed unique strain- and sex-dependent glomerular ECM signatures, which correlated with variations in levels of albuminuria and known predisposition to progressive nephropathy. Among the variation, we observed changes in netrin 4, fibroblast growth factor 2, tenascin C, collagen 1, meprin 1-α, and meprin 1-β. Differences in protein abundance were validated by quantitative immunohistochemistry and Western blot analysis, and the collective differences were not explained by mutations in known ECM or glomerular disease genes. Within the distinct signatures, we discovered a core set of structural ECM proteins that form multiple protein-protein interactions and are conserved from mouse to man. Furthermore, we found striking ultrastructural changes in glomerular basement membranes in FVB mice. Pathway analysis of merged transcriptomic and proteomic datasets identified potential ECM regulatory pathways involving inhibition of matrix metalloproteases, liver X receptor/retinoid X receptor, nuclear factor erythroid 2-related factor 2, notch, and cyclin-dependent kinase 5. These pathways may therefore alter ECM and confer susceptibility to disease.

  4. ESTIMATING TOTAL GLOMERULAR NUMBER IN HUMAN KIDNEYS WITH A PHYSICAL DISECTOR/FRACTIONATOR COMBINATION

    Directory of Open Access Journals (Sweden)

    Kelli J Johnson

    2011-05-01

    Full Text Available End-stage renal disease (ESRD has emerged as a major health issue for Australian Aborigines. This phenomenon is paralleled in other populations that have adopted a Westernised lifestyle, including African Americans. It has been suggested that abnormal glomerular hypertrophy (glomerulomegaly is an important predisposing factor for ESRD. The pathogenesis of glomerulomegaly remains unknown. It may represent a compensatory hypertrophic response to decreased nephron endowment during fetal development. Alternatively, glomerulomegaly may represent an abnormal haemodynamic/metabolic response to repeated infections, including renal infections during postnatal life. Since glomerular number and size are important issues associated with ESRD, an optimum quantitative method is required for estimating these parameters in human kidneys. The total number of glomeruli in the normal human kidney appears to vary by a factor of three or more, ranging from approximately 300,000 to more than 1 million. Recently, unbiased stereological methods for estimating total glomerular number in kidneys have been developed. The general aim of the present study was to evaluate (in terms of precision and efficiency a stereological method for estimating total glomerular number in human kidneys; the physical disector/fractionator combination. This method provided consistent estimates of total glomerular number. Estimates of total glomerular number obtained for four human kidneys ranged from 364,161 to 586,094 (coefficients of variation 9.2% to 20.0%. Mean glomerular volume for the four kidneys ranged from 6.04 to 10.32 μm3 x 106. These results indicate that this method is a precise and consistent method for estimating total glomerular number in human kidneys. The simple sampling technique developed in this study will be employed in future studies to determine if there is a difference in total glomerular, and hence nephron, number between Australian Aborigines and Caucasians, and

  5. Targeting Pediatric Glioma with Apoptosis and Autophagy Manipulation

    Science.gov (United States)

    2014-10-01

    shRNA against RAB7. We chose this because RAB7 similar to chloroquine, effects late stage autophagy with lysosomal fusion to the autophagosome. Thus...hypothesis that late stage autophagosome fusion with the lysosome and degradation of the components and recycling of the macronutrients is critical to...of autophagy, Rab7 and Lamp 2. We are now introducing siRNA against Rab7 and Lamp2 to reiterate the effects of Chloroquine inhibition of autophagy

  6. Characterization of early autophagy signaling by quantitative phosphoproteomics

    DEFF Research Database (Denmark)

    Rigbolt, Kristoffer Tg; Zarei, Mostafa; Sprenger, Adrian;

    2014-01-01

    Under conditions of nutrient shortage autophagy is the primary cellular mechanism ensuring availability of substrates for continuous biosynthesis. Subjecting cells to starvation or rapamycin efficiently induces autophagy by inhibiting the MTOR signaling pathway triggering increased autophagic flux....... To elucidate the regulation of early signaling events upon autophagy induction, we applied quantitative phosphoproteomics characterizing the temporal phosphorylation dynamics after starvation and rapamycin treatment. We obtained a comprehensive atlas of phosphorylation kinetics within the first 30 min upon...

  7. Beclin 1 complex in autophagy and Alzheimer disease.

    Science.gov (United States)

    Jaeger, Philipp A; Wyss-Coray, Tony

    2010-10-01

    Beclin 1 is a protein involved in the regulation of autophagy and has been shown to be reduced in patients with Alzheimer disease. This review summarizes the current research data that link disturbances in autophagy, a cellular degradation and maintenance pathway, to the development of Alzheimer disease and related neurodegenerative diseases. It also provides a brief overview of the existing pharmacological interventions available to modulate autophagy activity in mammalian cells.

  8. 4th International Symposium on Autophagy: exploiting the frontiers of autophagy research.

    Science.gov (United States)

    Eskelinen, Eeva-Liisa; Deretic, Vojo; Neufeld, Thomas; Levine, Beth; Cuervo, Ana Maria

    2007-01-01

    The 4th International Symposium on Autophagy was held in Mishima, a small town between Tokyo and Kyoto, October 1-5, 2006 (http://isa4th.umin.jp/). The meeting was organized by the group of Eiki Kominami. Approximately 150 participants took part in this well-organized meeting in the spacious and comfortable Toray Conference Hall (Fig. 1). The social program offered opportunities for informal discussions, Japanese culture (from karaoke singing to traditional drumming; Fig. 2), history and nature (a visit to a steaming volcano; Fig. 3), as well as delicious Japanese food. The scientific program started with two plenary lectures on Sunday evening. Daniel Klionsky gave an overview of Atg9 cycling in yeast and Shigekazu Nagata talked about apoptosis and engulfment of dead cells by macrophages. The meeting consisted of five oral sessions and two poster sessions covering a wide range of autophagy-related topics. Exciting unpublished results were presented in all sessions, showing how quickly autophagy research is progressing. Two themes were discussed in many sessions during the symposium: the role of autophagy in the degradation of aggregate-prone proteins and protein aggregates, and the possible role of p62 in autophagy.

  9. Does autophagy take a front seat in lifespan extension?

    OpenAIRE

    Petrovski, Goran; Das, Dipak K

    2010-01-01

    Abstract This review focuses on the interrelationship between ageing and autophagy. There is a striking similarity between the signalling aspects of these two processes. Both ageing and autophagy involve several of the signalling components such as insulin/IGF-1, AMPK, Ras-cAMP-PKA, Sch9 and mTOR. Ageing and ageing-mediated defective autophagy involve accumulation of lipofuscin. Components of anti-ageing and autophagy include SirTs and FoxOs. Nutritional deprivation or calorie restriction as ...

  10. Autophagy and bacterial infection: an evolving arms race.

    Science.gov (United States)

    Choy, Augustine; Roy, Craig R

    2013-09-01

    Autophagy is an important membrane transport pathway that is conserved among eukaryotic cells. Although first described as an intracellular catabolic pathway used to break down self-components, autophagy has been found to play an important role in the elimination of intracellular pathogens. A variety of host mechanisms exist for recognizing and targeting intracellular bacteria to autophagosomes. Several intracellular bacteria have evolved ways to manipulate, inhibit, or avoid autophagy in order to survive in the cell. Thus, the autophagy pathway can be viewed as an evolutionarily conserved host response to infection.

  11. Autophagy is essential for cardiac morphogenesis during vertebrate development.

    Science.gov (United States)

    Lee, Eunmyong; Koo, Yeon; Ng, Aylwin; Wei, Yongjie; Luby-Phelps, Kate; Juraszek, Amy; Xavier, Ramnik J; Cleaver, Ondine; Levine, Beth; Amatruda, James F

    2014-04-01

    Genetic analyses indicate that autophagy, an evolutionarily conserved lysosomal degradation pathway, is essential for eukaryotic differentiation and development. However, little is known about whether autophagy contributes to morphogenesis during embryogenesis. To address this question, we examined the role of autophagy in the early development of zebrafish, a model organism for studying vertebrate tissue and organ morphogenesis. Using zebrafish that transgenically express the fluorescent autophagy reporter protein, GFP-LC3, we found that autophagy is active in multiple tissues, including the heart, during the embryonic period. Inhibition of autophagy by morpholino knockdown of essential autophagy genes (including atg5, atg7, and becn1) resulted in defects in morphogenesis, increased numbers of dead cells, abnormal heart structure, and reduced organismal survival. Further analyses of cardiac development in autophagy-deficient zebrafish revealed defects in cardiac looping, abnormal chamber morphology, aberrant valve development, and ectopic expression of critical transcription factors including foxn4, tbx5, and tbx2. Consistent with these results, Atg5-deficient mice displayed abnormal Tbx2 expression and defects in valve development and chamber septation. Thus, autophagy plays an essential, conserved role in cardiac morphogenesis during vertebrate development.

  12. DNA damage response and Autophagy: a meaningful partnership

    Directory of Open Access Journals (Sweden)

    ARISTIDES G ELIOPOULOS

    2016-11-01

    Full Text Available Autophagy and the DNA damage response (DDR are biological processes essential for cellular and organismal homeostasis. Herein we summarize and discuss emerging evidence linking DDR to autophagy. We highlight published data suggesting that autophagy is activated by DNA damage and is required for several functional outcomes of DDR signaling, including repair of DNA lesions, senescence, cell death, and cytokine secretion. Uncovering the mechanisms by which autophagy and DDR are intertwined provides novel insight into the pathobiology of conditions associated with accumulation of DNA damage, including cancer and aging, and novel concepts for the development of improved therapeutic strategies against these pathologies.

  13. Autophagy is required for IL-2-mediated fibroblast growth

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Rui [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Tang, Daolin, E-mail: tangd2@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Lotze, Michael T., E-mail: lotzemt@upcm.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Zeh III, Herbert J., E-mail: zehh@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States)

    2013-02-15

    Autophagy is an evolutionarily conserved pathway responsible for delivery of cytoplasmic material into the lysosomal degradation pathway to enable vesicular exocytosis. Interleukin (IL)-2 is produced by T-cells and its activity is important for immunoregulation. Fibroblasts are an immune competent cell type, playing a critical role in wound healing, chronic inflammation, and tumor development. Although autophagy plays an important role in each of these processes, whether it regulates IL-2 activity in fibroblasts is unknown. Here, we show that autophagy is required for IL-2-induced cell growth in fibroblasts. IL-2 significantly induced autophagy in mouse embryonic fibroblasts (MEFs) and primary lung fibroblasts. Autophagy inhibitors (e.g., 3-methylamphetamine and bafilomycin A1) or knockdown of ATG5 and beclin 1 blocked clinical grade IL-2-induced autophagy. Moreover, IL-2 induced HMGB1 cytoplasmic translocation in MEFs and promoted interaction between HMGB1 and beclin1, which is required for autophagy induction. Pharmacological and genetic inhibition of autophagy inhibited IL-2-induced cell proliferation and enhanced IL-2-induced apoptosis. These findings suggest that autophagy is an important pro-survival regulator for IL-2-induced cell growth in fibroblasts.

  14. Autophagy and the Cell Cycle: A Complex Landscape

    Science.gov (United States)

    Mathiassen, Søs Grønbæk; De Zio, Daniela; Cecconi, Francesco

    2017-01-01

    Autophagy is a self-degradation pathway, in which cytoplasmic material is sequestered in double-membrane vesicles and delivered to the lysosome for degradation. Under basal conditions, autophagy plays a homeostatic function. However, in response to various stresses, the pathway can be further induced to mediate cytoprotection. Defective autophagy has been linked to a number of human pathologies, including neoplastic transformation, even though autophagy can also sustain the growth of tumor cells in certain contexts. In recent years, a considerable correlation has emerged between autophagy induction and stress-related cell-cycle responses, as well as unexpected roles for autophagy factors and selective autophagic degradation in the process of cell division. These advances have obvious implications for our understanding of the intricate relationship between autophagy and cancer. In this review, we will discuss our current knowledge of the reciprocal regulation connecting the autophagy pathway and cell-cycle progression. Furthermore, key findings involving nonautophagic functions for autophagy-related factors in cell-cycle regulation will be addressed.

  15. Application and interpretation of current autophagy inhibitors and activators

    Institute of Scientific and Technical Information of China (English)

    Ya-ping YANG; Li-fang HU; Hui-fen ZHENG; Cheng-jie MAO; Wei-dong HU; Kang-ping XIONG; Fen WANG

    2013-01-01

    Aut ophagy is the major intracellular degradation system,by which cytoplasmic materials are delivered to and degraded in the lysosome.As a quality control mechanism for cytoplasmic proteins and organelles,autophagy plays important roles in a variety of human diseases,including neurodegenerative diseases,cancer,cardiovascular disease,diabetes and infectious and inflammatory diseases.The discovery of ATG genes and the dissection of the signaling pathways involved in regulating autophagy have greatly enriched our knowledge on the occurrence and development of this lysosomal degradation pathway.In addition to its role in degradation,autophagy may also promote a type of programmed cell death that is different from apoptosis,termed type II programmed cell death.Owing to the dual roles of autophagy in cell death and the specificity of diseases,the exact mechanisms of autophagy in various diseases require more investigation.The application of autophagy inhibitors and activators will help us understand the regulation of autophagy in human diseases,and provide insight into the use of autophagy-targeted drugs.In this review,we summarize the latest research on autophagy inhibitors and activators and discuss the possibility of their application in human disease therapy.

  16. Angiotensin II and renal prostaglandin release in the dog. Interactions in controlling renal blood flow and glomerular filtration rate.

    Science.gov (United States)

    Bugge, J F; Stokke, E S

    1994-04-01

    The relationship between angiotensin II and renal prostaglandins, and their interactions in controlling renal blood flow (RBF) and glomerular filtration rate (GFR) were investigated in 18 anaesthetized dogs with acutely denervated kidneys. Intrarenal angiotensin II infusion increased renal PGE2 release (veno-arterial concentration difference times renal plasma flow) from 1.7 +/- 0.9 to 9.1 +/- 0.4 and 6-keto-PGF1 alpha release from 0.1 +/- 0.1 to 5.3 +/- 2.1 pmol min-1. An angiotensin II induced reduction in RBF of 20% did not measurably change GFR whereas a 30% reduction reduced GFR by 18 +/- 8%. Blockade of prostaglandin synthesis approximately doubled the vasoconstrictory action of angiotensin II, and all reductions in RBF were accompanied by parallel reductions in GFR. When prostaglandin release was stimulated by infusion of arachidonic acid (46.8 +/- 13.3 and 15.9 +/- 5.4 pmol min-1 for PGE2, and 6-keto-PGF1 alpha, respectively), angiotensin II did not change prostaglandin release, but had similar effects on the relationship between RBF and GFR as during control. In an ureteral occlusion model with stopped glomerular filtration measurements of ureteral pressure and intrarenal venous pressure permitted calculations of afferent and efferent vascular resistances. Until RBF was reduced by 25-30% angiotensin II increased both afferent and efferent resistances almost equally, keeping the ureteral pressure constant. At greater reductions in RBF, afferent resistance increased more than the efferent leading to reductions in ureteral pressure. This pattern was not changed by blockade of prostaglandin synthesis indicating no influence of prostaglandins on the distribution of afferent and efferent vascular resistances during angiotensin II infusion. In this ureteral occlusion model glomerular effects of angiotensin II will not be detected, and it might well be that the shift from an effect predominantly on RBF to a combined effect on both RBF and GFR induced by inhibition

  17. Lithium nephrotoxicity: a progressive combined glomerular and tubulointerstitial nephropathy.

    Science.gov (United States)

    Markowitz, G S; Radhakrishnan, J; Kambham, N; Valeri, A M; Hines, W H; D'Agati, V D

    2000-08-01

    This study examines the clinical features, pathologic findings, and outcome of 24 patients with biopsy-proven lithium toxicity. The patient population was 50% male, 87.5% Caucasian, and had a mean age of 42.5 yr (range, 26 to 57). Mean duration of lithium therapy for bipolar disorder was 13.6 yr (range, 2 to 25). All patients were biopsied for renal insufficiency (mean serum creatinine 2.8 mg/dl; range, 1.3 to 8.0), with associated proteinuria >1.0 g/d in 41.7%. Nephrotic proteinuria (>3.0 g/d) was present in 25%. Other features included nephrogenic diabetes insipidus in 87% and hypertension in 33.3%. Renal biopsy revealed a chronic tubulointerstitial nephropathy in 100%, with associated cortical and medullary tubular cysts (62.5%) or dilatation (33.3%). All of the renal cysts stained for epithelial membrane antigen, while 51.4% stained with lectin Arachis hypogaea, and only 3.8% stained with Tetragonolobus purpureas, indicating they originated from distal and collecting tubules. The degree of tubular atrophy and interstitial fibrosis was graded as severe in 58.3%, moderate in 37.5%, and mild in 4.2% of cases. There was a surprisingly high prevalence of focal segmental glomerulosclerosis (50%) and global glomerulosclerosis (100%), sometimes of equivalent severity to the chronic tubulointerstitial disease. The significant degree of foot process effacement (mean 34%, five of 14 cases with >50%) suggests a potential direct glomerular toxicity. Focal segmental glomerulosclerosis correlated with proteinuria >1.0 g/d (P = 0.0014, Fisher exact test). Despite discontinuation of lithium, seven of nine patients with initial serum creatinine values >2.5 mg/dl progressed to end-stage renal disease (ESRD). Only three patients, all with initial serum creatinine 2.5 mg/dl at biopsy (P = 0. 008). In conclusion, lithium nephrotoxicity primarily targets distal and collecting tubules, with a higher incidence of proteinuria and associated glomerular pathology than recognized

  18. Autophagy Regulatory Network - a systems-level bioinformatics resource for studying the mechanism and regulation of autophagy.

    Science.gov (United States)

    Türei, Dénes; Földvári-Nagy, László; Fazekas, Dávid; Módos, Dezső; Kubisch, János; Kadlecsik, Tamás; Demeter, Amanda; Lenti, Katalin; Csermely, Péter; Vellai, Tibor; Korcsmáros, Tamás

    2015-01-01

    Autophagy is a complex cellular process having multiple roles, depending on tissue, physiological, or pathological conditions. Major post-translational regulators of autophagy are well known, however, they have not yet been collected comprehensively. The precise and context-dependent regulation of autophagy necessitates additional regulators, including transcriptional and post-transcriptional components that are listed in various datasets. Prompted by the lack of systems-level autophagy-related information, we manually collected the literature and integrated external resources to gain a high coverage autophagy database. We developed an online resource, Autophagy Regulatory Network (ARN; http://autophagy-regulation.org), to provide an integrated and systems-level database for autophagy research. ARN contains manually curated, imported, and predicted interactions of autophagy components (1,485 proteins with 4,013 interactions) in humans. We listed 413 transcription factors and 386 miRNAs that could regulate autophagy components or their protein regulators. We also connected the above-mentioned autophagy components and regulators with signaling pathways from the SignaLink 2 resource. The user-friendly website of ARN allows researchers without computational background to search, browse, and download the database. The database can be downloaded in SQL, CSV, BioPAX, SBML, PSI-MI, and in a Cytoscape CYS file formats. ARN has the potential to facilitate the experimental validation of novel autophagy components and regulators. In addition, ARN helps the investigation of transcription factors, miRNAs and signaling pathways implicated in the control of the autophagic pathway. The list of such known and predicted regulators could be important in pharmacological attempts against cancer and neurodegenerative diseases.

  19. Polydatin regulates proliferation, apoptosis and autophagy in multiple myeloma cells through mTOR/p70s6k pathway

    Science.gov (United States)

    Yang, Baojun; Zhao, Shunxin

    2017-01-01

    Background Polydatin (PD) plays an important role in suppressing platelet aggregation, reducing blood lipid, restoring microcirculation and protecting from myocardial ischemia/reperfusion injury and shock. In addition, PD possesses anticancer activity. However, the effect and the mechanism of PD in regulating multiple myeloma (MM) cell survival and death are still unknown. Methods Cell proliferation and apoptosis of RPMI 8226 cells, respectively, were analyzed by cell counting kit8 (CCK-8) assay and flow cytometry. The levels of caspase-3, cleaved caspase-3, caspase-9, cleaved caspase-9, Bcl-2 and Bax were analyzed by Western blot. Autophagy induced by PD was investigated by detecting the levels of Beclin 1, Atg5, LC3I, LC3II, HSP70 and HSP27. The autophagy inhibitor 3-methyladenine (3-MA), mTOR/p70s6k inhibitor rapamycin, and mTOR activator MHY1485 were used to analyze the mechanism of cell proliferation, apoptosis and autophagy influenced by PD. The phosphorylations of mTOR and p70s6k were detected by Western blot. Results A gradual decrease in cell proliferation of RPMI 8226 cells was observed with an increase in PD concentrations (Pcell apoptosis and autophagy in a concentration-dependent manner. Both 3-MA and MHY1485 reversed the inhibitory effect of PD on cell proliferation and attenuated the positive effect of PD on cell apoptosis and autophagy. The phosphorylation of mTOR and p70s6k was significantly suppressed by PD (Pcell viability (Pcell proliferation and induced apoptosis and autophagy of MM cells via the mTOR/p70s6k signaling pathway in a concentration-dependent manner in vitro, indicating that PD could be a potential anticancer drug for MM therapy.

  20. The human CD5L/AIM-CD36 axis: A novel autophagy inducer in macrophages that modulates inflammatory responses.

    Science.gov (United States)

    Sanjurjo, Lucía; Amézaga, Núria; Aran, Gemma; Naranjo-Gómez, Mar; Arias, Lilibeth; Armengol, Carolina; Borràs, Francesc E; Sarrias, Maria-Rosa

    2015-01-01

    CD5L (CD5 molecule-like) is a secreted glycoprotein that participates in host response to bacterial infection. CD5L influences the monocyte inflammatory response to the bacterial surface molecules lipopolysaccharide (LPS) and lipoteichoic acid (LTA) by inhibiting TNF secretion. Here we studied the intracellular events that lead to macrophage TNF inhibition by human CD5L. To accomplish this goal, we performed functional analyses with human monocytic THP1 macrophages, as well as with peripheral blood monocytes. Inhibition of phosphatidylinositol 3-kinase (PtdIns3K) reversed the inhibitory effect of CD5L on TNF secretion. Among the various PtdIns3K isoforms, our results indicated that CD5L activates PtdIns3K (whose catalytic subunit is termed PIK3C3), a key modulator involved in autophagy. Further analysis revealed a concomitant enhancement of autophagy markers such as cellular LC3-II content, increased LC3 puncta, as well as LC3-LysoTracker Red colocalization. Moreover, electron microscopy showed an increased presence of cytosolic autophagosomes in THP1 macrophages overexpressing CD5L. Besides preventing TNF secretion, CD5L also inhibited IL1B and enhanced IL10 secretion. This macrophage anti-inflammatory pattern of CD5L was reverted upon silencing of autophagy protein ATG7 by siRNA transfection. Additional siRNA experiments in THP1 macrophages indicated that the induction of autophagy mechanisms by CD5L was achieved through cell-surface scavenger receptor CD36, a multiligand receptor expressed in a wide variety of cell types. Our data represent the first evidence that CD36 is involved in autophagy and point to a significant contribution of the CD5L-CD36 axis to the induction of macrophage autophagy.

  1. mTOR inhibition increases cell viability via autophagy induction during endoplasmic reticulum stress - An experimental and modeling study.

    Science.gov (United States)

    Kapuy, Orsolya; Vinod, P K; Bánhegyi, Gábor

    2014-01-01

    Unfolded or misfolded proteins in the endoplasmic reticulum (ER) trigger an adaptive ER stress response known as unfolded protein response (UPR). Depending on the severity of ER stress, either autophagy-controlled survival or apoptotic cell death can be induced. The molecular mechanisms by which UPR controls multiple fate decisions have started to emerge. One such molecular mechanism involves a master regulator of cell growth, mammalian target of rapamycin (mTOR), which paradoxically is shown to have pro-apoptotic role by mutually interacting with ER stress response. How the interconnections between UPR and mTOR influence the dynamics of autophagy and apoptosis activation is still unclear. Here we make an attempt to explore this problem by using experiments and mathematical modeling. The effect of perturbed mTOR activity in ER stressed cells was studied on autophagy and cell viability by using agents causing mTOR pathway inhibition (such as rapamycin or metyrapone). We observed that mTOR inhibition led to an increase in cell viability and was accompanied by an increase in autophagic activity. It was also shown that autophagy was activated under conditions of severe ER stress but that in the latter phase of stress it was inhibited at the time of apoptosis activation. Our mathematical model shows that both the activation threshold and temporal dynamics of autophagy and apoptosis inducers are sensitive to variation in mTOR activity. These results confirm that autophagy has cytoprotective role and is activated in mutually exclusive manner with respect to ER stress levels.

  2. EFFECTS OF RAPAMYCIN ON INTRACELLULAR CHOLESTEROL HOMEOSTASIS OF GLOMERULAR MESANGIAL CELL IN THE PRESENCE OF INTERLEUKIN-1β

    Institute of Scientific and Technical Information of China (English)

    Guo-juan Zhang; Hang Li; Xue-wang Li

    2008-01-01

    Objective To investigate the effects of rapamycin on cholesterol homeostasis of glomerular mesangial cells and the underlying mechanisms.Methods Intracellular cholesterol accttmulation was measured by Oil Red O staining and high performance liquid chromatography.The effects of rapamycin on interleukin-1β (IL-1β)-induced mRNA and protein changes of low-density lipoprotein receptor (LDLR) and ATP-binding cassette transporter Al (ABCAl) were assayed by quantitative real-time PCR and Western blot.Transient expressions of 3 types of mammalian target of rapamycin (mTOR),including mTOR-WT (wild type),mTOR-RR (rapamycin resistant,with kinase activity),and mTOR-RR-KD (rapamycin resistant,without kinase activity),were obtained by plasmid transfection.Results Rapamycin had no significant influence on intracellular cholesterol concentration under normal condition,but it significantly decreased the intracelhilar cholesterol concentration in the presence of IL-1β.Rapamycin dose-dependently suppressed the increased expression of LDLR induced by IL-1β and up-regulated the suppressed expression of ABCAl caused by IL-Iβ.Transient expression of 3 types of roTOR all reduced ABCAl InRNA expression significantly,which all could be overroded by rapamycin.Conclusions Rapamycin may contribute to the maintaining of glomerular mesangial cell intracellular cholesterol homeostasis under inflammatory state by both reducing cholesterol uptake and increasing cholesterol efflux.And the effect may be not completely mediated by mTOR.

  3. MicroRNA regulation of Autophagy

    DEFF Research Database (Denmark)

    Frankel, Lisa B; Lund, Anders H

    2012-01-01

    recently contributed to our understanding of the molecular mechanisms of the autophagy machinery, yet several gaps remain in our knowledge of this process. The discovery of microRNAs (miRNAs) established a new paradigm of post-transcriptional gene regulation and during the past decade these small non......-coding RNAs have been closely linked to virtually all known fundamental biological pathways. Deregulation of miRNAs can contribute to the development of human diseases, including cancer, where they can function as bona fide oncogenes or tumor suppressors.In this review, we highlight recent advances linking miRNAs...... perspective, but also from a therapeutic view, where miRNAs can be harnessed experimentally to alter autophagy levels in human tumors, affecting parameters such as tumor survival and treatment sensitivity....

  4. Value of electron microscopy in the diagnosis of glomerular diseases.

    Science.gov (United States)

    Darouich, Sihem; Goucha, Rym Louzir; Jaafoura, Mohamed Habib; Moussa, Fatma Ben; Zekri, Semy; Maiz, Hédi Ben

    2010-04-01

    To evaluate the contribution of electron microscopy to the final diagnosis of glomerulopathies, the authors established a prospective study during the first semester of 2006. A total of 52 kidney biopsies were performed with 3 samples for light microscopy, immunofluorescence, and electron microscopy. Among these renal biopsies, only 20 were examined with electron microscopy because the diagnosis made on the basis of conventional methods had remained unclear or doubtful. In 18 cases, electron microscopy was undertaken for the investigation of primary kidney disease. The 2 remaining cases were transplant biopsies. In this series of 20 patients, there were 3 children with an average age of 9 years and 17 adults with an average age of 35.5 years. Fifteen patients (75%) were nephrotic. The study revealed that electron microscopy was essential for diagnosis in 8 cases (40%) and was helpful in 12 cases (60%). In conclusion, the results showed that the ultrastructural study provides essential or helpful information in many cases of glomerular diseases, and therefore electron microscopy should be considered an important tool of diagnostic renal pathology. As was recommended, it is important to reserve renal tissue for ultrastructural study unless electron microscopy can be routinely used in all biopsies. Thus, this technique could be performed wherever a renal biopsy has to be ultrastructurally evaluated.

  5. C9orf72’s interaction with Rab GTPases - modulation of membrane traffic and autophagy

    Directory of Open Access Journals (Sweden)

    Bor Luen Tang

    2016-10-01

    Full Text Available Hexanucleotide repeat expansion in an intron of Chromosome 9 open reading frame 72 (C9orf72 is the most common genetic cause of Amyotrophic Lateral Sclerosis (ALS and Frontotemporal Dementia (FTD. While functional haploinsufficiency of C9orf72 resulting from the mutation may play a role in ALS/FTD, the actual cellular role of the protein has been unclear. Recent findings have now shown that C9orf72 physically and functionally interacts with multiple members of the Rab small GTPases family, consequently exerting important influences on cellular membrane traffic and the process of autophagy. Loss of C9orf72 impairs endocytosis in neuronal cell lines, and attenuated autophagosome formation. Interestingly, C9orf72 could influence autophagy both as part of a Guanine nucleotide exchange factor (GEF complex, or as a Rab effector that facilitates transport of the Unc-51-like Autophagy Activating Kinase 1 (Ulk1 autophagy initiation complex. The cellular function of C9orf72 is discussed in the light of these recent findings

  6. C9orf72’s Interaction with Rab GTPases—Modulation of Membrane Traffic and Autophagy

    Science.gov (United States)

    Tang, Bor L.

    2016-01-01

    Hexanucleotide repeat expansion in an intron of Chromosome 9 open reading frame 72 (C9orf72) is the most common genetic cause of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). While functional haploinsufficiency of C9orf72 resulting from the mutation may play a role in ALS/FTD, the actual cellular role of the protein has been unclear. Recent findings have now shown that C9orf72 physically and functionally interacts with multiple members of the Rab small GTPases family, consequently exerting important influences on cellular membrane traffic and the process of autophagy. Loss of C9orf72 impairs endocytosis in neuronal cell lines, and attenuated autophagosome formation. Interestingly, C9orf72 could influence autophagy both as part of a Guanine nucleotide exchange factor (GEF) complex, or as a Rab effector that facilitates transport of the Unc-51-like Autophagy Activating Kinase 1 (Ulk1) autophagy initiation complex. The cellular function of C9orf72 is discussed in the light of these recent findings. PMID:27774051

  7. Autophagy and the (Pro)renin Receptor.

    Science.gov (United States)

    Binger, Katrina J; Muller, Dominik N

    2013-10-21

    The (pro)renin receptor (PRR) is a newly reported member of the renin-angiotensin system (RAS); a hormonal cascade responsible for regulating blood pressure. Originally, identification of PRR was heralded as the next drug target of the RAS, of which such therapies would have increased benefits against target-organ damage and hypertension. However, in the years since its discovery, several conditional knockout mouse models of PRR have demonstrated an essential role for this receptor unrelated to the RAS and blood pressure. Specific deletion of PRR in podocytes or cardiomyocytes resulted in the rapid onset of organ failure and subsequently animal mortality after only a matter of weeks. In both cell types, loss of PRR resulted in the intracellular accumulation of autophagosomes and misfolded proteins, indicating a disturbance in autophagy. In light of the fact that the majority of PRR is located intracellularly, this molecular function appears to be more relevant than its ability to bind to high, non-physiological concentrations of (pro)renin. This review will focus on the role of PRR in autophagy and its importance in maintaining cellular homeostasis. Understanding the link between PRR, autophagy and how its loss results in cell death will be essential for deciphering its role in physiology and pathology.

  8. Autophagy and ethanol-induced liver injury

    Institute of Scientific and Technical Information of China (English)

    Terrence M Donohue Jr

    2009-01-01

    The majority of ethanol metabolism occurs in the liver. Consequently, this organ sustains the greatest damage from ethanol abuse. Ethanol consumption disturbs the delicate balance of protein homeostasis in the liver, causing intracellular protein accumulation due to a disruption of hepatic protein catabolism.Evidence indicates that ethanol or its metabolism impairs trafficking events in the liver, including the process of macroautophagy, which is the engulfment and degradation of cytoplasmic constituents by the lysosomal system. Autophagy is an essential, ongoing cellular process that is highly regulated by nutrients,endocrine factors and signaling pathways. A great number of the genes and gene products that govern the autophagic response have been characterized and the major metabolic and signaling pathways that activate or suppress autophagy have been identified. This review describes the process of autophagy, its regulation and the possible mechanisms by which ethanol disrupts the process of autophagic degradation. The implications of autophagic suppression are discussed in relation to the pathogenesis of alcohol-induced liver injury.

  9. Regulation of autophagy by nucleoporin Tpr.

    Science.gov (United States)

    Funasaka, Tatsuyoshi; Tsuka, Eriko; Wong, Richard W

    2012-01-01

    The nuclear pore complex (NPC) consists of a conserved set of ~30 different proteins, termed nucleoporins, and serves as a gateway for the exchange of materials between the cytoplasm and nucleus. Tpr (translocated promoter region) is a component of NPC that presumably localizes at intranuclear filaments. Here, we show that Tpr knockdown caused a severe reduction in the number of nuclear pores. Furthermore, our electron microscopy studies indicated a significant reduction in the number of inner nuclear filaments. In addition, Tpr siRNA treatment impaired cell growth and proliferation compared to control siRNA-treated cells. In Tpr-depleted cells, the levels of p53 and p21 proteins were enhanced. Surprisingly, Tpr depletion increased p53 nuclear accumulation and facilitated autophagy. Our study demonstrates for the first time that Tpr plays a role in autophagy through controlling HSP70 and HSF1 mRNA export, p53 trafficking with karyopherin CRM1, and potentially through direct transcriptional regulation of autophagy factors.

  10. Progresión de la Poliquistosis renal autosómica dominante: Influencia de polimorfismos de genes de sintasa endotelial del óxido nítrico (ecNOS y del sistema renina-angiotensina Glomerular filtration rate decline in autosomic dominant polycystic kidney disease. Influence of endothelial NO synthase (ecNOS and renin angiotensin system gene polymorphisms

    Directory of Open Access Journals (Sweden)

    Pablo Azurmendi

    2004-04-01

    Full Text Available La velocidad de progresión (VdP de la poliquistosis renal autosómica dominante (PQRAD es variable. Estudiamos la asociación de los polimorfismos AGTM235T (angiotensinógeno, AT1A1166C (ATR1 y ecNOSGlu298Asp (NO sintasa endotelial con la VdP en 88 pacientes. VdP fue estimada por 1/Cr pl vs edad. Consideramos edades de Cr pl 2 y 6 mg/dl como comienzo de progresión (E2 y arribo a insuficiencia renal crónica terminal (E6, respectivamente. Los polimorfismos se estudiaron por PCR-RFLP. El grupo en su totalidad presentó VdP (ml/min/año de 6.9±0.5, E2 y E6 de 48.9±1.3 y 55.0±1.4 años y tensión arterial media (TAM de 111.2±1.2 mmHg. Según E6 observamos dos grupos (£ y > a 55 años. En £ 55 (fenotipo PKD1, n=42, E2 y E6 del genotipo CC de AT1A1166C fueron 36.0±1.2 y 41.4±0.9 años vs. AA-AC (42.8±1.0 y 47.5±0.8, p Glomerular filtration rate decline (GFRd is variable in autosomic dominant polycystic kidney disease (ADPKD. In 88 ADPKD patients, GFRd was assessed by 1/S Cr and compared with the association to AT1A1166C (AT1R, AGTM235T (angiotensinogen and ecNOSGlu298Asp (NO endothelial synthase polymorphisms. Age at S Cr values of 2 and 6 mg/dl were assumed as beginning of progressive phase (A2 and end-stage-renal disease (A6, respectively. Polymorphisms were studied by PCR-RFLP. The group as a whole showed GFRd (ml/min/year of 6.9±0.5; A2 and A6 of 48.9±1.3 and 55.0±1.4 years and mean arterial pressure of 111.2±1.2 mmHg. When A6 was considered, two populations were defined (£ and > 55 years. In £ 55 (assumed as PKD1 phenotype (n=42, A2 and A6 of the AT11166CC genotype were 36.0±1.2 and 41.4±0.9 years vs AA-AC (42.8±1.0 and 47.5±0.8, p<0.001. A2 and A6 of the ecNOS298Asp/Asp genotype were 34.8±1.5 and 41.1±0.6 years vs. Glu/Glu-Glu/Asp (42.4±0.9 and 47.1±0.8, p<0.02. In AGT235TT genotype, GFRd was 12.4±2.2 ml/min/year vs MM-MT (7.9±0.7, p<0.03. This difference was also observed when all ADPKD patients were considered (TT

  11. Tissue transglutaminase inhibition as treatment for diabetic glomerular scarring: it's good to be glueless.

    Science.gov (United States)

    Schelling, Jeffrey R

    2009-08-01

    Diabetic nephropathy is characterized by enhanced glomerular and tubulointerstitial deposition of extracellular matrix proteins, which are bound together by tissue transglutaminase (TG2). Huang et al. demonstrate that infusion of a novel TG2 inhibitor in diabetic rats prevented renal scarring and albuminuria and preserved glomerular filtration rate. These studies confirm the role of TG2 in the pathogenesis of diabetic nephropathy and add to an emerging literature that demonstrates that TG2 is an attractive therapeutic target for sclerosing kidney diseases.

  12. Anti-glomerular basement membrane glomerulonephritis and thrombotic microangiopathy in first degree relatives; a case report

    OpenAIRE

    Idorn Thomas; Schejbel Lone; Rydahl Casper; Heaf James; Jølvig Karen; Bergstrøm Marie; Garred Peter; Kamper Anne-Lise

    2012-01-01

    Abstract Background Anti-glomerular basement membrane glomerulonephritis and thrombotic microangiopathy are rare diseases with no known coherence. Case Presentation A daughter and her biological mother were diagnosed with pregnancy-induced thrombotic microangiopathy and anti-glomerular basement membrane glomerulonephritis, respectively. Both developed end-stage renal disease. Exploration of a common aetiology included analyses of HLA genotypes, functional and genetic aspects of the complement...

  13. Inhibition of lovastatin on proliferation and expression of proinflammatory cytokines in cultured human glomerular mesangial cells

    Institute of Scientific and Technical Information of China (English)

    李航; 李学旺; 段琳; 李晨红

    2003-01-01

    Objective To study the effects and mechanism of lovastatin on cell proliferation and expression of proinflammatory cytokines in cultured human glomerular mesangial cells.Methods The influence of lovastatin on HMC proliferation was evaluated with 3H-thymidine incorporation. mRNA expression of proinflammatory cytokines (IL-1β, IL-6, TNF-α, and MCP-1) and activation of NF-κB of HMC were measured using Reverse transcription-polymerase chain reaction (RT-PCR) and electrophoretic mobility shift assay (EMSA) respectively.Results Lovastatin was found to have inhibitory effects on human mesangial cell (HMC) proliferation and lipopolysaccharide (LPS)-mediated human mesangine cell HMC mRNA expression of proinflammatory cytokines via activation of NF-κB. The effect of lovstatin on HMC could be prevented when the mevalonate and farnesol were added to the culture.Conclusion Lovastatin may decrease HMC proliferation and production of proinflammatory cytokines through the inhibition of NF-κB activation. This provided experimental evidence for further evaluation of the renal protective effect of HRI, suggesting that it may be a potent agent for prevention of progressive reanl diseases aside from its lipid-lowering effect.

  14. Podocyte EphB4 signaling helps recovery from glomerular injury.

    Science.gov (United States)

    Wnuk, Monika; Hlushchuk, Ruslan; Janot, Mathilde; Tuffin, Gérald; Martiny-Baron, Georg; Holzer, Philipp; Imbach-Weese, Patricia; Djonov, Valentin; Huynh-Do, Uyen

    2012-06-01

    Eph receptor tyrosine kinases and their ligands (ephrins) have a pivotal role in the homeostasis of many adult organs and are widely expressed in the kidney. Glomerular diseases beginning with mesangiolysis can recover, with podocytes having a critical role in this healing process. We studied here the role of Eph signaling in glomerular disease recovery following mesangiolytic Thy1.1 nephritis in rats. EphB4 and ephrinBs were expressed in healthy glomerular podocytes and were upregulated during Thy1.1 nephritis, with EphB4 strongly phosphorylated around day 9. Treatment with NPV-BHG712, an inhibitor of EphB4 phosphorylation, did not cause glomerular changes in control animals. Nephritic animals treated with vehicle did not have morphological evidence of podocyte injury or loss; however, application of this inhibitor to nephritic rats induced glomerular microaneurysms, podocyte damage, and loss. Prolonged NPV-BHG712 treatment resulted in increased albuminuria and dysregulated mesangial recovery. Additionally, NPV-BHG712 inhibited capillary repair by intussusceptive angiogenesis (an alternative to sprouting angiogenesis), indicating a previously unrecognized role of podocytes in regulating intussusceptive vessel splitting. Thus, our results identify EphB4 signaling as a pathway allowing podocytes to survive transient capillary collapse during glomerular disease.

  15. Olfactory aversive conditioning alters olfactory bulb mitral/tufted cell glomerular odor responses

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    Max L Fletcher

    2012-03-01

    Full Text Available The anatomical organization of receptor neuron input into the olfactory bulb (OB allows odor information to be transformed into an odorant-specific spatial map of mitral/tufted cell glomerular activity at the upper level of the olfactory bulb. In other sensory systems, neuronal representations of stimuli can be reorganized or enhanced following learning. While the mammalian OB has been shown to undergo experience-dependent plasticity at the glomerular level, it is still unclear if similar representational change occurs within mitral/tufted cell glomerular odor representations following learning. To address this, odorant-evoked glomerular activity patterns were imaged in mice expressing a GFP-based calcium indicator (GCaMP2 in OB mitral/tufted cells. Glomerular odor responses were imaged before and after olfactory associative conditioning to aversive foot shock. Following conditioning, we found no overall reorganization of the glomerular representation. Training, however, did significantly alter the amplitudes of individual glomeruli within the representation in mice in which the odor was presented together with foot shock. Further, the specific pairing of foot shock with odor presentations lead to increased responses primarily in initially weakly activated glomeruli. Overall, these results suggest that associative conditioning can enhance the initial representation of odors within the olfactory bulb by enhancing responses to the learned odor in some glomeruli.

  16. Effects of salt restriction on renal growth and glomerular injury in rats with remnant kidneys.

    Science.gov (United States)

    Lax, D S; Benstein, J A; Tolbert, E; Dworkin, L D

    1992-06-01

    Male Munich-Wistar rats underwent right nephrectomy and infarction of two thirds of the left kidney. Rats were randomly assigned to ingest standard chow (REM) or a moderately salt restricted chow (LS). A third group of rats were fed the low salt diet and were injected with an androgen (LSA). Eight weeks after ablation, glomerular volume and glomerular capillary radius were markedly increased in REM. This increase was prevented by the low salt diet, however, the antihypertrophic effect of the diet was overcome by androgen. Values for glomerular volume and capillary radius were similar in LSA and REM. Morphologic studies revealed that approximately 25% of glomeruli were abnormal in REM. Much less injury was observed in salt restricted rats, however, the protective effect of the low salt diet was significantly abrogated when renal growth was stimulated in salt restricted rats by androgen. Micropuncture studies revealed that glomerular pressure was elevated in all three groups and not affected by diet or androgen. Serum cholesterol was also similar in the three groups. These findings indicate that renal and glomerular hypertrophy are correlated with the development of glomerular injury after reduction in renal mass and suggest that dietary salt restriction lessens renal damage, at least in part, by inhibiting compensatory renal growth.

  17. Autophagy in the human placenta throughout gestation.

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    Tai-Ho Hung

    Full Text Available BACKGROUND: Autophagy has been reported to be essential for pre-implantation development and embryo survival. However, its role in placental development and regulation of autophagy during pregnancy remain unclear. The aims of this study were to (1 study autophagy by characterizing changes in levels of beclin-1, DRAM, and LC3B in human placenta throughout gestation; (2 determine whether autophagy is involved in regulation of trophoblast invasion in JEG-3 cells (a choriocarcinoma cell line; (3 examine the effects of reduced oxygen and glucose on the autophagic changes; and (4 investigate the effect of reoxygenation and supplementation of glucose after oxygen-glucose deprivation (OGD on the autophagic changes in primary cytotrophoblasts obtained from normal term pregnancy. METHODOLOGY/PRINCIPAL FINDINGS: An analysis of 40 placental samples representing different gestational stages showed (1 no significant differences in beclin-1, DRAM, and LC3B-II levels in placentas between early and mid-gestation, and late gestation with vaginal delivery; (2 placentas from late gestation with cesarean section had lower levels of LC3B-II compared to early and mid-gestation, and late gestation with vaginal delivery; levels of DRAM were also lower compared to placentas from early and mid-gestation; and (3 using explant cultures, villous tissues from early and late gestation had similar rates of autophagic flux under physiological oxygen concentrations. Knockdown of BECN1, DRAM, and LC3B had no effects on viability and invasion activity of JEG-3 cells. On the other hand, OGD caused a significant increase in the levels of LC3B-II in primary cytotrophoblasts, while re-supplementation of oxygen and glucose reduced these changes. Furthermore, there were differential changes in levels of beclin-1, DRAM, and LC3B-II in response to changes in oxygen and glucose levels. CONCLUSIONS/SIGNIFICANCE: Our results indicate that autophagy is involved in development of the human

  18. Autophagy: A double-edged sword in Alzheimer's disease

    Indian Academy of Sciences (India)

    Ying-Tsen Tung; Bo-Jeng Wang; Ming-Kuan Hu; Wen-Ming Hsu; Hsinyu Lee; Wei-Pang Huang; Yung-Feng Liao

    2012-03-01

    Autophagy is a major protein degradation pathway that is essential for stress-induced and constitutive protein turnover. Accumulated evidence has demonstrated that amyloid- (A) protein can be generated in autophagic vacuoles, promoting its extracellular deposition in neuritic plaques as the pathological hallmark of Alzheimer’s disease (AD). The molecular machinery for A generation, including APP, APP-C99 and -/-secretases, are all enriched in autophagic vacuoles. The induction of autophagy can be vividly observed in the brain at early stages of sporadic AD and in an AD transgenic mouse model. Accumulated evidence has also demonstrated a neuroprotective role of autophagy in mediating the degradation of aggregated proteins that are causative of various neurodegenerative diseases. Autophagy is thus widely regarded as an intracellular hub for the removal of the detrimental A peptides and Tau aggregates. Nonetheless, compelling data also reveal an unfavorable function of autophagy in facilitating the production of intracellular A. The two faces of autophagy on the homeostasis of A place it in a very unique and intriguing position in ADpathogenesis. This article briefly summarizes seminal discoveries that are shedding new light on the critical and unique roles of autophagy in AD and potential therapeutic approaches against autophagy-elicited AD.

  19. Autophagy in ageing and ageing-associated diseases

    Institute of Scientific and Technical Information of China (English)

    Li-qiang HE; Jia-hong LU; Zhen-yu YUE

    2013-01-01

    Autophagy is a cell self-digestion process via lysosomes that clears "cellular waste",including aberrantly modified proteins or protein aggregates and damaged organelles.Therefore,autophagy is considered a protein and organelle quality control mechanism that maintains normal cellular homeostasis.Dysfunctional autophagy has been observed in ageing tissues and several ageing-associated diseases.Lifespan of model organisms such as yeast,worms,flies,and mice can be extended through promoting autophagy,either by genetic manipulations such as over-expression of Sirtuin 1,or by administrations of rapamycin,resveratrol or spermidine.The evidence supports that autophagy may play an important role in delaying ageing or extending lifespan.In this review,we summarize the current knowledge about autophagy and its regulation,outline recent developments ie the genetic and pharmacological manipulations of autophagy that affects the lifespan,and discuss the role of autophagy in the ageing-related diseases.ow in Center for Neurodegenerative and Neuroimmunologic Diseases,Department of Neurology,University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School,Piscataway,NJ 08854,USA

  20. Exercise induces autophagy in peripheral tissues and in the brain.

    Science.gov (United States)

    He, Congcong; Sumpter, Rhea; Levine, Beth

    2012-10-01

    We recently identified physical exercise as a newly defined inducer of autophagy in vivo. Exercise induced autophagy in multiple organs involved in metabolic regulation, such as muscle, liver, pancreas and adipose tissue. To study the physiological role of exercise-induced autophagy, we generated mice with a knock-in nonphosphorylatable mutation in BCL2 (Thr69Ala, Ser70Ala and Ser84Ala) (BCL2 AAA) that are defective in exercise- and starvation-induced autophagy but not in basal autophagy. We found that BCL2 AAA mice could not run on a treadmill as long as wild-type mice, and did not undergo exercise-mediated increases in skeletal glucose muscle uptake. Unlike wild-type mice, the BCL2 AAA mice failed to reverse high-fat diet-induced glucose intolerance after 8 weeks of exercise training, possibly due to defects in signaling pathways that regulate muscle glucose uptake and metabolism during exercise. Together, these findings suggested a hitherto unknown important role of autophagy in mediating exercise-induced metabolic benefits. In the present addendum, we show that treadmill exercise also induces autophagy in the cerebral cortex of adult mice. This observation raises the intriguing question of whether autophagy may in part mediate the beneficial effects of exercise in neurodegeneration, adult neurogenesis and improved cognitive function.

  1. Autophagy: A Potential Link between Obesity and Insulin Resistance

    NARCIS (Netherlands)

    P. Codogno; A.J. Meijer

    2010-01-01

    Dysregulation of autophagy contributes to aging and to diseases such as neurodegeneration, cardiomyopathy, and cancer. The paper by Yang et al. (2010) in this issue of Cell Metabolism indicates that defective autophagy may also underlie impaired insulin sensitivity in obesity and that upregulating a

  2. Altered autophagy in human adipose tissues in obesity

    Science.gov (United States)

    Context: Autophagy is a housekeeping mechanism, involved in metabolic regulation and stress response, shown recently to regulate lipid droplets biogenesis/breakdown and adipose tissue phenotype. Objective: We hypothesized that in human obesity autophagy may be altered in adipose tissue in a fat d...

  3. Polymorphisms in autophagy genes and susceptibility to tuberculosis.

    NARCIS (Netherlands)

    Songane, M.; Kleinnijenhuis, J.; Alisjahbana, B.; Sahiratmadja, E.; Parwati, I.; Oosting, M.; Plantinga, T.S.; Joosten, L.A.B.; Netea, M.G.; Ottenhoff, T.H.; Vosse, E. van de; Crevel, R. van

    2012-01-01

    Recent data suggest that autophagy is important for intracellular killing of Mycobacterium tuberculosis, and polymorphisms in the autophagy gene IRGM have been linked with susceptibility to tuberculosis (TB) among African-Americans, and with TB caused by particular M. tuberculosis genotypes in Ghana

  4. Autophagy Is Associated with Pathogenesis of Haemophilus parasuis

    Science.gov (United States)

    Zhang, Yaning; Li, Yufeng; Yuan, Wentao; Xia, Yuting; Shen, Yijuan

    2016-01-01

    Haemophilus parasuis (H. parasuis) is a common commensal Gram-negative extracellular bacterium in the upper respiratory tract of swine, which can cause Glässer's disease in stress conditions. Research on the pathogenicity of H. parasuis has mainly focused on immune evasion and bacterial virulence factors, while few studies have examined the interactions of H. parasuis and its host. Autophagy is associated with the replication and proliferation of many pathogenic bacteria, but whether it plays a role during infection by H. parasuis is unknown. In this study, an adenovirus construct expressing GFP, RFP, and LC3 was used to infect H. parasuis. Western blotting, laser confocal microscopy, and electron microscopy showed that Hps5 infection induced obvious autophagy in PK-15 cells. In cells infected with strains of H. parasuis differing in invasiveness, the levels of autophagy were positively correlated with the presence of alive bacteria in PK-15 cells. In addition, autophagy inhibited the invasion of Hps5 in PK-15 cells. Autophagy related genes Beclin, Atg5 and Atg7 were silenced with RNA interference, the results showed that autophagy induced by H. parasuis infection is a classical pathway. Our observations demonstrate that H. parasuis can induce autophagy and that the levels of autophagy are associated with the presence of alive bacteria in cells, which opened novel avenues to further our understanding of H. parasuis-host interplay and pathogenesis. PMID:27703447

  5. Role of Autophagy in the Control of Body Metabolism

    Directory of Open Access Journals (Sweden)

    Wenying Quan

    2013-03-01

    Full Text Available Autophagy plays a crucial role in the maintenance of cellular nutrient balance and the function of organelles such as mitochondria or the endoplasmic reticulum, which are important in intracellular metabolism, insulin release, and insulin sensitivity. In the insulin-producing pancreatic β-cells, autophagy is important in the maintenance of β-cell mass, structure, and function. Mice with deficiencies in β-cell-specific autophagy show reduced β-cell mass and defects in insulin secretion that lead to hypoinsulinemia and hyperglycemia but not diabetes. However, these mice developed diabetes when bred with ob/ob mice, suggesting that autophagy-deficient β-cells have defects in dealing with the increased metabolic stress imposed by obesity. These results also imply that autophagy deficiency in β-cells could be a factor in the progression from obesity to diabetes. Another important function of autophagy is in hypothalamic neurons for the central control of energy expenditure, appetite, and body weight. In addition, mice with autophagy deficiencies in the target tissues of insulin have yielded diverse phenotypes. Taken together, these results suggest that autophagy is important in the control of whole body energy and nutrient homeostasis, and its dysregulation could play a role in the development of metabolic disorders and diabetes.

  6. Autophagy suppresses host adaptive immune responses toward Borrelia burgdorferi

    NARCIS (Netherlands)

    Buffen, Kathrin; Oosting, Marije; Li, Yang; Kanneganti, Thirumala-Devi; Netea, Mihai G.; Joosten, Leo A. B.

    2016-01-01

    Inhibition of autophagy increases the severity of murine Lyme arthritis and human adaptive immune responses against B. burgdorferi. We have previously demonstrated that inhibition of autophagy increased the Borrelia burgdorferi induced innate cytokine production in vitro, but little is known regardi

  7. Autophagy mediates pharmacological lifespan extension by spermidine and resveratrol.

    Science.gov (United States)

    Morselli, Eugenia; Galluzzi, Lorenzo; Kepp, Oliver; Criollo, Alfredo; Maiuri, Maria Chiara; Tavernarakis, Nektarios; Madeo, Frank; Kroemer, Guido

    2009-12-23

    Although autophagy has widely been conceived as a self-destructive mechanism that causes cell death, accumulating evidence suggests that autophagy usually mediates cytoprotection, thereby avoiding the apoptotic or necrotic demise of stressed cells. Recent evidence produced by our groups demonstrates that autophagy is also involved in pharmacological manipulations that increase longevity. Exogenous supply of the polyamine spermidine can prolong the lifespan of (while inducing autophagy in) yeast, nematodes and flies. Similarly, resveratrol can trigger autophagy in cells from different organisms, extend lifespan in nematodes, and ameliorate the fitness of human cells undergoing metabolic stress. These beneficial effects are lost when essential autophagy modulators are genetically or pharmacologically inactivated, indicating that autophagy is required for the cytoprotective and/or anti-aging effects of spermidine and resveratrol. Genetic and functional studies indicate that spermidine inhibits histone acetylases, while resveratrol activates the histone deacetylase Sirtuin 1 to confer cytoprotection/longevity. Although it remains elusive whether the same histones (or perhaps other nuclear or cytoplasmic proteins) act as the downstream targets of spermidine and resveratrol, these results point to an essential role of protein hypoacetylation in autophagy control and in the regulation of longevity.

  8. Genetic Modifiers of White Blood Cell Count, Albuminuria and Glomerular Filtration Rate in Children with Sickle Cell Anemia

    Science.gov (United States)

    Flanagan, Jonathan M.; Alvarez, Ofelia A.; Nelson, Stephen C.; Aygun, Banu; Nottage, Kerri A.; George, Alex; Roberts, Carla W.; Piccone, Connie M.; Howard, Thad A.; Davis, Barry R.; Ware, Russell E.

    2016-01-01

    Discovery and validation of genetic variants that influence disease severity in children with sickle cell anemia (SCA) could lead to early identification of high-risk patients, better screening strategies, and intervention with targeted and preventive therapy. We hypothesized that newly identified genetic risk factors for the general African American population could also impact laboratory biomarkers known to contribute to the clinical disease expression of SCA, including variants influencing the white blood cell count and the development of albuminuria and abnormal glomerular filtration rate. We first investigated candidate genetic polymorphisms in well-characterized SCA pediatric cohorts from three prospective NHLBI-supported clinical trials: HUSTLE, SWiTCH, and TWiTCH. We also performed whole exome sequencing to identify novel genetic variants, using both a discovery and a validation cohort. Among candidate genes, DARC rs2814778 polymorphism regulating Duffy antigen expression had a clear influence with significantly increased WBC and neutrophil counts, but did not affect the maximum tolerated dose of hydroxyurea therapy. The APOL1 G1 polymorphism, an identified risk factor for non-diabetic renal disease, was associated with albuminuria. Whole exome sequencing discovered several novel variants that maintained significance in the validation cohorts, including ZFHX4 polymorphisms affecting both the leukocyte and neutrophil counts, as well as AGGF1, CYP4B1, CUBN, TOR2A, PKD1L2, and CD163 variants affecting the glomerular filtration rate. The identification of robust, reliable, and reproducible genetic markers for disease severity in SCA remains elusive, but new genetic variants provide avenues for further validation and investigation. PMID:27711207

  9. Maternal glomerular filtration rate in pregnancy and fetal size.

    Directory of Open Access Journals (Sweden)

    Nils-Halvdan Morken

    Full Text Available BACKGROUND: The relationship of maternal glomerular filtration rate (GFR in pregnancy to fetal size needs to be better characterized as it impacts an ongoing debate about confounding effect of maternal GFR in investigations of important environmental contaminants. We aimed to characterize the size of the association between maternal GFR and infant birth weight. MATERIALS AND METHODS: A sub-cohort of 953 selected women (470 women with and 483 women without preeclampsia in the Norwegian Mother and Child Cohort (MoBa, recruited during 2003-2007 were analyzed. GFR in the second trimester was estimated based on plasma creatinine. Birth weight was ascertained from the Medical Birth Registry of Norway. Multivariate linear regression was used to evaluate the association between maternal GFR in second trimester (estimated by the Cockroft-Gault [GFR-CG] and the modification of diet in renal disease [GFR-MDRD] formulas and infant birth weight. Partial correlation coefficients were also calculated. RESULTS: Maternal GFR-CG (β: 0.73 g/ml/min, p = 0.04 and GFR-MDRD (β: 0.83 g/ml/min, p = 0.04 were associated with infant birth weight in models adjusted for maternal weight in kilograms, preeclampsia, and gestational age at delivery (days. Partial correlation coefficients for the association between infant birth weight and GFR were 0.07 for both formulas. Although the birth weight-GFR association was stronger among the women with preeclampsia, the difference from women without preeclampsia was not statistically significant. CONCLUSION: These data support an association between GFR during pregnancy and infant birth weight, and indicate that GFR may confound selected epidemiologic associations.

  10. /sup 125/I iothalamate an ideal marker for glomerular filtration

    Energy Technology Data Exchange (ETDEWEB)

    Odlind, B.; Haellgren, R.S.; Sohtell, M.; Lindstroem, B.

    1985-01-01

    The triiodinated angiographic contrast medium, iothalamate (usually labelled /sup 125/I), has been used extensively as a marker for glomerular filtration. The authors have studied the renal handling of /sup 125/I iothalamate (IOT) in vivo and in vitro in several species. In renal cortical slices from chicken, rabbit, rat, and monkey, the tissue-to-medium ratio of IOT was twice that of /sup 51/Cr-EDTA (EDTA) at 37 degrees C; a difference that was abolished at 0 degree C and markedly reduced by added o-iodohippurate or iodipamide. In five chickens the steady-state renal clearance of IOT (CIOT) was twice that of EDTA (CEDTA) or /sup 3/H inulin (C1); a difference that was abolished by administration of 100 mg/kg/hr of novobiocin, an organic anion transport inhibitor. CEDTA was similar to C1 before as well as after transport inhibition. Utilizing the Sperber technique the mean apparent tubular excretion fraction (ATEF) of IOT was 8%, while that of EDTA was 1%. After novobiocin coinfusion (new steady-state) ATEFIOT was significantly reduced and not different from that of EDTA (-1%). In the same animals the total urinary recovery of IOT was 84 and 57% before and after novobiocin, respectively, while corresponding values for EDTA was unchanged by the inhibitor. In seven rats the renal extraction of IOT was reduced from 29 to 17% by coinfusion of probenecid (5 mg/kg/hr). Corresponding extractions were 82 to 34% and 22% (unchanged) for PAH and EDTA, respectively.

  11. Estimating glomerular filtration rate preoperatively for patients undergoing hepatectomy

    Institute of Scientific and Technical Information of China (English)

    Yoshimi Iwasaki; Tokihiko Sawada; Shozo Mori; Yukihiro Iso; Masato Katoh; Kyu Rokkaku; Junji Kita; Mitsugi Shimoda; Keiichi Kubota

    2009-01-01

    AIM: To compare creatinine clearance (Ccr) with estimated glomerular filtration rate (eGFR) in preoperative renal function tests in patients undergoing hepatectomy. METHODS: The records of 197 patients undergoing hepatectomy between August 2006 and August 2008 were studied, and preoperative Ccr, a three-variable equation for eGFR (eGFR3) and a five-variable equation for eGFR (eGFR5) were calculated. Abnormal values were defined as Ccr < 50 mL/min, eGFR3 and eGFR5 < 60 mL/min per 1.73 m2. The maximum increases in the postoperative serum creatinine (post Cr) level and postoperative rate of increase in the serum Cr level (post Cr rate) were compared. RESULTS: There were 37 patients (18.8%) withabnormal Ccr, 31 (15.7%) with abnormal eGFR3, and 40 (20.3%) with abnormal eGFR5. Although there were no significant differences in the post Cr rate between patients with normal and abnormal Ccr, eGFR3 and eGFR5 values, the post Cr level was significantly higher in patients with eGFR3 and eGFR5 abnormality than in normal patients ( P < 0.0001). Post Cr level tended to be higher in patients with Ccr abnormality ( P = 0.0936 and P = 0.0875, respectively). CONCLUSION: eGFR5 and the simpler eGFR3, rather than Ccr, are recommended as a preoperative renal function test in patients undergoing hepatectomy.

  12. Production of monoclonal antibodies to human glomerular basement membrane.

    Directory of Open Access Journals (Sweden)

    Mino,Yasuaki

    1984-10-01

    Full Text Available Using the technique of somatic cell fusion, we produced monoclonal antibodies to collagenase-digested human glomerular basement membrane (GBM. Fourteen monoclonal antibodies which reacted with normal human kidney in indirect immunofluorescence (IIF studies were produced. An analysis of the binding patterns indicated that the antigens recognized could be divided into six broad groups. Monoclonal antibody B3-H10 (Group 1 reacted with only GBM in a fine granular pattern. A5-B12 and B5-C2 (Group 2 reacted with GBM and peritubular capillary in a linear pattern. B2-A12 (Group 3 reacted with only epithelial cells. Al-C9 and A4-E2 (Group 4 showed a mesangial pattern in glomerulus and a lineal pattern in tubular basement membrane (TBM, Bowman's capsule and peritubular capillary. A1-E1, A1-E11, A2-E6, A3-B6, A4-F8 and B5-H2 (Group 5 recognized determinants common to GBM, TBM, Bowman's capsule and/or peritubular capillary. A3-F1 and B5-E10 (Group 6 reacted with TBM and Bowman's capsule. The staining pattern of B3-H10 (Group 1 was characteristic because it was not linear, but finely granular along the GBM. The staining pattern of B2-A12 (Group 3 was also characteristic because only epithelial cells were stained, and processes of epithelial cells were observed as fine fibrils. To the best of our knowledge, these two types of monoclonal antibodies have not been reported previously.

  13. Role of glomerular proteoglycans in IgA nephropathy.

    Science.gov (United States)

    Ebefors, Kerstin; Granqvist, Anna; Ingelsten, Madeleine; Mölne, Johan; Haraldsson, Börje; Nyström, Jenny

    2011-04-06

    Mesangial matrix expansion is a prominent feature of the most common form of glomerulonephritis, IgA nephropathy (IgAN). To find molecular markers and improve the understanding of the disease, the gene and protein expression of proteoglycans were investigated in biopsies from IgAN patients and correlated to clinical and morphological data. We collected and microdissected renal biopsies from IgAN patients (n = 19) and from healthy kidney donors (n = 14). Patients were followed for an average time of 4 years and blood pressure was according to target guidelines. Distinct patterns of gene expression were seen in glomerular and tubulo-interstitial cells. Three of the proteoglycans investigated were found to be of special interest and upregulated in glomeruli: perlecan, decorin and biglycan. Perlecan gene expression negatively correlated to albumin excretion and progress of the disease. Abundant decorin protein expression was found in sclerotic glomeruli, but not in unaffected glomeruli from IgAN patients or in controls. Transforming growth factor beta (TGF-β), known to interact with perlecan, decorin and biglycan, were upregulated both on gene and protein level in the glomeruli. This study provides further insight into the molecular mechanisms involved in mesangial matrix expansion in IgAN. We conclude that perlecan is a possible prognostic marker for patients with IgAN. In addition, the up-regulation of biglycan and decorin, as well as TGF-β itself, indicate that regulation of TGF-β, and other profibrotic markers plays a role in IgAN pathology.

  14. Deficiency of the planar cell polarity protein Vangl2 in podocytes affects glomerular morphogenesis and increases susceptibility to injury.

    Science.gov (United States)

    Rocque, Brittany L; Babayeva, Sima; Li, Jane; Leung, Vicki; Nezvitsky, Lisa; Cybulsky, Andrey V; Gros, Philippe; Torban, Elena

    2015-03-01

    The planar cell polarity (PCP) signaling pathway is crucial for tissue morphogenesis. Van Gogh-like protein 2 (Vangl2) is central in the PCP pathway; in mice, Vangl2 loss is embryonically lethal because of neural tube defects, and mutations in Vangl2 are associated with human neural tube defects. In the kidney, PCP signaling may be important for tubular morphogenesis and organization of glomerular epithelial cells (podocytes) along the glomerular basement membrane. Podocyte cell protrusions (foot processes) are critical for glomerular permselectivity; loss of foot process architecture results in proteinuria and FSGS. Previously, we showed a profound effect of PCP signaling on podocyte shape, actin rearrangement, cell motility, and nephrin endocytosis. To test our hypothesis that the PCP pathway is involved in glomerular development and function and circumvent lethality of the ubiquitous Vangl2 mutation in the Looptail mouse, we generated a mouse model with a podocyte-specific ablation of the Vangl2 gene. We report here that podocyte-specific deletion of Vangl2 leads to glomerular maturation defects in fetal kidneys. In adult mice, we detected significantly smaller glomeruli, but it did not affect glomerular permselectivity in aging animals. However, in the context of glomerular injury induced by injection of antiglomerular basement membrane antibody, deletion of Vangl2 resulted in exacerbation of injury and accelerated progression to chronic segmental and global glomerular sclerosis. Our results indicate that Vangl2 function in podocytes is important for glomerular development and protects against glomerular injury in adult animals.

  15. Modulation of Autophagy-Like Processes by Tumor Viruses

    Directory of Open Access Journals (Sweden)

    Karl Munger

    2012-06-01

    Full Text Available Autophagy is an intracellular degradation pathway for long-lived proteins and organelles. This process is activated above basal levels upon cell intrinsic or environmental stress and dysregulation of autophagy has been linked to various human diseases, including those caused by viral infection. Many viruses have evolved strategies to directly interfere with autophagy, presumably to facilitate their replication or to escape immune detection. However, in some cases, modulation of autophagy appears to be a consequence of the virus disturbing the cell’s metabolic signaling networks. Here, we summarize recent advances in research at the interface of autophagy and viral infection, paying special attention to strategies that human tumor viruses have evolved.

  16. Host Cell Autophagy in Immune Response to Zoonotic Infections

    Directory of Open Access Journals (Sweden)

    Panagiotis Skendros

    2012-01-01

    Full Text Available Autophagy is a fundamental homeostatic process in which cytoplasmic targets are sequestered within double-membraned autophagosomes and subsequently delivered to lysosomes for degradation. Accumulating evidence supports the pivotal role of autophagy in host defense against intracellular pathogens implicating both innate and adaptive immunity. Many of these pathogens cause common zoonotic infections worldwide. The induction of the autophagic machinery by innate immune receptors signaling, such as TLRs, NOD1/2, and p62/SQSTM1 in antigen-presenting cells results in inhibition of survival and elimination of invading pathogens. Furthermore, Th1 cytokines induce the autophagic process, whereas autophagy also contributes to antigen processing and MHC class II presentation, linking innate to adaptive immunity. However, several pathogens have developed strategies to avoid autophagy or exploit autophagic machinery to their advantage. This paper focuses on the role of host cell autophagy in the regulation of immune response against intracellular pathogens, emphasizing on selected bacterial and protozoan zoonoses.

  17. Autophagy process is associated with anti-neoplastic function

    Institute of Scientific and Technical Information of China (English)

    Chong Wang; Yachen Wang; Michael A. McNutt; Wei-Guo Zhu

    2011-01-01

    Autophagy is a highly conserved process of cellular degradation, which is present in yeast, plants, and mammals.Under normal physiological conditions, autophagy acts to maintain cellular homeostasis and regulate the turnover of organelles.In response to cellular stresses, autophagy prevents the accumulation of impaired proteins and organelles, which serves to inhibit carcinogenesis.On this basis,it is widely accepted that most tumor suppressors, such as beclin 1 associated proteins, forkhead box class O (FoxO)family proteins, multiple mammalian target of Rapamycin (mTOR) inactivators, and nuclear p53 play a role in indu cing autophagy.Here, we focus on how the process of autophagy is associated with anti-neoplastic function.

  18. Autophagy in Plants--What's New on the Menu?

    Science.gov (United States)

    Michaeli, Simon; Galili, Gad; Genschik, Pascal; Fernie, Alisdair R; Avin-Wittenberg, Tamar

    2016-02-01

    Autophagy is a major cellular degradation pathway in eukaryotes. Recent studies have revealed the importance of autophagy in many aspects of plant life, including seedling establishment, plant development, stress resistance, metabolism, and reproduction. This is manifested by the dual ability of autophagy to execute bulk degradation under severe environmental conditions, while simultaneously to be highly selective in targeting specific compartments and protein complexes to regulate key cellular processes, even during favorable growth conditions. Delivery of cellular components to the vacuole enables their recycling, affecting the plant metabolome, especially under stress. Recent research in Arabidopsis has further unveiled fundamental mechanistic aspects in autophagy which may have relevance in non-plant systems. We review the most recent discoveries concerning autophagy in plants, touching upon all these aspects.

  19. Targeting autophagy to sensitive glioma to temozolomide treatment.

    Science.gov (United States)

    Yan, Yuanliang; Xu, Zhijie; Dai, Shuang; Qian, Long; Sun, Lunquan; Gong, Zhicheng

    2016-02-02

    Temozolomide (TMZ), an alkylating agent, is widely used for treating primary and recurrent high-grade gliomas. However, the efficacy of TMZ is often limited by the development of resistance. Recently, studies have found that TMZ treatment could induce autophagy, which contributes to therapy resistance in glioma. To enhance the benefit of TMZ in the treatment of glioblastomas, effective combination strategies are needed to sensitize glioblastoma cells to TMZ. In this regard, as autophagy could promote cell survival or autophagic cell death, modulating autophagy using a pharmacological inhibitor, such as chloroquine, or an inducer, such as rapamycin, has received considerably more attention. To understand the effectiveness of regulating autophagy in glioblastoma treatment, this review summarizes reports on glioblastoma treatments with TMZ and autophagic modulators from in vitro and in vivo studies, as well as clinical trials. Additionally, we discuss the possibility of using autophagy regulatory compounds that can sensitive TMZ treatment as a chemotherapy for glioma treatment.

  20. Berberine attenuates autophagy in adipocytes by targeting BECN1.

    Science.gov (United States)

    Deng, Yujie; Xu, Jun; Zhang, Xiaoyan; Yang, Jian; Zhang, Di; Huang, Jian; Lv, Pengfei; Shen, Weili; Yang, Ying

    2014-10-01

    The lysosomal degradation pathway, autophagy, is essential for the maintenance of cellular homeostasis. Recently, autophagy has been demonstrated to be required in the process of adipocyte conversion. However, its role in mature adipocytes under physiological and pathological conditions remains unclear. Here, we report a major function of BECN1 in the regulation of basal autophagy in mature adipocytes. We also show that berberine, a natural plant alkaloid, inhibits basal autophagy in adipocytes and adipose tissue of mice fed a high-fat diet via downregulation of BECN1 expression. We further demonstrate that berberine has a pronounced effect on the stability of Becn 1 mRNA through the Mir30 family. These findings explore the potential of BECN1 as a key molecule and a drug target for regulating autophagy in mature adipocytes.

  1. Mitochondrial accumulation under oxidative stress is due to defects in autophagy.

    Science.gov (United States)

    Luo, Cheng; Li, Yan; Wang, Hui; Feng, Zhihui; Li, Yuan; Long, Jiangang; Liu, Jiankang

    2013-01-01

    Mitochondrial dynamics maintains normal mitochondrial function by degrading damaged mitochondria and generating newborn mitochondria. The accumulation of damaged mitochondria influences the intracellular environment by promoting mitochondrial dysfunction, and thus initiating a vicious cycle. Oxidative stress induces mitochondrial malfunction, which is involved in many cardiovascular diseases. However, the mechanism of mitochondrial accumulation in cardiac myoblasts remains unclear. We observed mitochondrial dysfunction and an increase in mitochondrial mass under the oxidative conditions produced by tert-butyl hydroperoxide (tBHP) in cardiac myoblast H9c2 cells. However, in contrast to the increase in mitochondrial mass, mitochondrial DNA (mtDNA) decreased, suggesting that enhanced mitochondrial biogenesis may be not the primary cause of the mitochondrial accumulation. Therefore, we investigated changes in a number of proteins involved in autophagy. Beclin1, Atg12-Atg5 conjugate, Atg7 contents decreased but LC3-II accumulated in tBHP-treated H9c2 cells. Moreover, the capacity for acid hydrolysis decreased in H9c2 cells. We also demonstrated a decrease in DJ-1 protein under the oxidative conditions that deregulate mitochondrial dynamics. These results reveal that autophagy became defective under oxidative stress. We therefore suggest that defects in autophagy mediate mitochondrial accumulation under these conditions.

  2. Redox regulation of autophagy in healthy brain and neurodegeneration.

    Science.gov (United States)

    Hensley, Kenneth; Harris-White, Marni E

    2015-12-01

    Autophagy and redox biochemistry are two major sub disciplines of cell biology which are both coming to be appreciated for their paramount importance in the etiology of neurodegenerative diseases including Alzheimer's disease (AD). Thus far, however, there has been relatively little exploration of the interface between autophagy and redox biology. Autophagy normally recycles macro-molecular aggregates produced through oxidative-stress mediated pathways, and also may reduce the mitochondrial production of reactive oxygen species through recycling of old and damaged mitochondria. Conversely, dysfunction in autophagy initiation, progression or clearance is evidenced to increase aggregation-prone proteins in neural and extraneural tissues. Redox mechanisms of autophagy regulation have been documented at the level of cross-talk between the Nrf2/Keap1 oxidant and electrophilic defense pathway and p62/sequestosome-1 (SQSTM1)-associated autophagy, at least in extraneural tissue; but other mechanisms of redox autophagy regulation doubtless remain to be discovered and the relevance of such processes to maintenance of neural homeostasis remains to be determined. This review summarizes current knowledge regarding the relationship of redox signaling, autophagy control, and oxidative stress as these phenomena relate to neurodegenerative disease. AD is specifically addressed as an example of the theme and as a promising indication for new therapies that act through engagement of autophagy pathways. To exemplify one such novel therapeutic entity, data is presented that the antioxidant and neurotrophic agent lanthionine ketimine-ethyl ester (LKE) affects autophagy pathway proteins including beclin-1 in the 3xTg-AD model of Alzheimer's disease where the compound has been shown to reduce pathological features and cognitive dysfunction.

  3. EXPERIMENTS ON THE GLOMERULAR DISTRIBUTION OF BLOOD IN THE MAMMALIAN KIDNEY.

    Science.gov (United States)

    Hayman, J M; Starr, I

    1925-10-31

    increase and decrease respectively in number of glomeruli through which blood flows (see Text-fig. 1). Analogous changes apparently occur in the capillary pathway in individual glomeruli. Hence renal function in mammals may be altered by changes in the extent of glomerular filtration surface to which the blood has access. Other conditions remaining the same, it is obvious that changes in extent of filtration surface must result in proportionate changes in urinary output. The figures for rate of urine elimination at the time of injection of the dye in these experiments are in substantial agreement with these statements (see Text-fig. 2). Exceptions to our chief conclusion as stated have been encountered. In Experiment 57,86 per cent of the glomeruli were open in a constricted kidney which was excreting no urine: in Experiment 30, 16 per cent were open in the kidney which was eliminating seven drops per minute: the outputs of the kidneys in the caffeine experiments were far higher than those of control kidneys in which comparable numbers of glomeruli were open. In considering these exceptions, account must be taken of the fact that other conditions do not commonly remain constant. When a renal vasodilator is introduced we conceive not only of possible increase in extent of accessible glomerular surface, but also of increase in glomerular pressure and increased rate of renewal of fluid in contact with glomerular membranes. Hence the response is greater than can be accounted for by any one factor alone. A basis of experiment exists in support of the belief that usually sufficient differences in physiological state exist among the small arteries and arterioles of the kidney so that a constrictor influence, exerted equally upon all, elicits various degrees of response (1). Closure of some, continuing patency of others, results. Blood flow and blood pressure in the glomeruli which are supplied by the vessels which remain open may be decreased, increased, or unchanged according

  4. Glomerular filtration rate, cardiovascular risk factors and insulin resistance Filtrado glomerular, riesgo cardiovascular y resistencia a la insulina

    Directory of Open Access Journals (Sweden)

    Martín R. Salazar

    2009-10-01

    Full Text Available The aim of this paper was to study the estimated glomerular filtration rate (eGFR, its changes with age, and its association with systolic blood pressure (SBP and diastolic BP (DBP, indicators of obesity, dyslipemia, insulin resistance and inflammation on a random population sample. BP, weight, size and waist circumference (WC were recorded at home. Fasting morning blood samples were analysed. The eGFR was calculated with MDRD (eGFR-MDRD, Cockroft-Gault (eGFR-CG adjusted to 1.73 m² and reciprocal of serum creatinine (100/serum cretinine. A total of 1016 individuals, 722 females (41.97 ± 0.66 years old and 294 males (42.06 ± 0.99 years old, completed the laboratory tests. The mean of 100/Scr was 115.13 ± 0.60 (dl/mg, the mean eGFR-CG was 98.48 ± 0.82 ml/min/1.73 m²; the mean eGFR-MDRD was 85.15 ± 0.58 ml/min/1.73 m². The eGFR-MDRD decreased with age and with the number of risk factors in both sexes. The eGFR-MDRD El objetivo fue evaluar en una muestra poblacional aleatoria el filtrado glomerular estimado (FGe, sus cambios con la edad y su asociación con presión arterial sistólica (PAS y diastólica (PAD, indicadores de obesidad, dislipemia, resistencia a la insulina e inflamación. En cada domicilio fueron medidos presión arterial, peso y talla y perímetro de la cintura (PC. Se analizaron muestras de sangre en ayunas y fue calculado el FGe usando las fórmulas de MDRD (FGe-MDRD y Cockroft-Gault (FGe-CG ajustado a 1.73 m², y la inversa de la creatinina sérica (100/CrS. Completaron el protocolo de laboratorio 1016 sujetos, 722 mujeres (41.97 ± 0.66 años y 294 varones (42.06 ± 0.99 años. La media de 100/Crs fue 115.13 ± 0.60 (dl/mg, la del FGe-CG 98.48 ± 0.82 ml/min/1.73 m² y la del FGe-MDRD 85.15 ± 0.58 ml/min/1.73 m² (CI 95% 84.00-86.29. El FGe-MDRD disminuyó con la edad y con el número de factores de riesgo cardiovascular en ambos sexos. La prevalecencia ajustada de FGe-MDRD < 60 ml/min/1.73 m² fue 6.2 por 100

  5. Deep hypothermia-enhanced autophagy protects PC12 cells against oxygen glucose deprivation via a mitochondrial pathway.

    Science.gov (United States)

    Tang, Dang; Wang, Cheng; Gao, Yongjun; Pu, Jun; Long, Jiang; Xu, Wei

    2016-10-06

    Deep hypothermia is known for its organ-preservation properties, which is introduced into surgical operations on the brain and heart, providing both safety in stopping circulation as well as an attractive bloodless operative field. However, the molecular mechanisms have not been clearly identified. This study was undertaken to determine the influence of deep hypothermia on neural apoptosis and the potential mechanism of these effects in PC12 cells following oxygen-glucose deprivation. Deep hypothermia (18°C) was given to PC12 cells while the model of oxygen-glucose deprivation (OGD) induction for 1h. After 24h of reperfusion, the results showed that deep hypothermia decreased the neural apoptosis, and significantly suppressed overexpression of Bax, CytC, Caspase 3, Caspase 9 and cleaved PARP-1, and inhibited the reduction of Bcl-2 expression. While deep hypothermia increased the LC3II/LC3I and Beclin 1, an autophagy marker, which can be inhibited by 3-methyladenine (3-MA), indicating that deep hypothermia-enhanced autophagy ameliorated apoptotic cell death in PC12 cells subjected to OGD. Based on these findings we propose that deep hypothermia protects against neural apoptosis after the induction of OGD by attenuating the mitochondrial apoptosis pathway, moreover, the mechanism of these antiapoptosis effects is related to the enhancement of autophagy, which autophagy might provide a means of neuroprotection against OGD.

  6. Molecular sieve of the rat glomerular basement membrane: a transmission electron microscopic study of enzyme-treated specimens.

    Directory of Open Access Journals (Sweden)

    Ichiyasu,Akira

    1988-12-01

    Full Text Available Isolated rat glomerular basement membrane was treated with elastase and observed by transmission electron microscopy. The treatment with elastase revealed the fundamental structure of the glomerular basement membrane quite clearly, and enabled the observation of a sieve structure within the glomerular basement membrane. This sieve structure may play a major role in the filtration of blood as well as in the production of urine. Treatment with antibody showed that the sieve was mainly constituted of type IV collagen.

  7. Study on the Relationship between Blood Stasis Syndrome and Clinical Pathology in 227 Patients with Primary Glomerular Disease

    Institute of Scientific and Technical Information of China (English)

    李深; 饶向荣; 王素霞; 张改华; 李晓玫; 戴希文; 陈可冀

    2009-01-01

    To investigate the relationship between the severity of Chinese medicine(CM) bloodstasis syndrome(BSS) with clinical features and renal lesion indexes of the primary glomerular disease. Methods:An epidemiological survey was conducted to collect the data of 227 patients diagnosed as chronic primary glomerular diseases,and their severity of BSS were scored three days before renal biopsies were performed.The following clinical indexes were analyzed:age,course of glomerular diseases,24-h urine protein ration...

  8. Laser stimulation can activate autophagy in HeLa cells

    Science.gov (United States)

    Wang, Yisen; Lan, Bei; He, Hao; Hu, Minglie; Cao, Youjia; Wang, Chingyue

    2014-10-01

    For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca2+ dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

  9. Laser stimulation can activate autophagy in HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yisen; Hu, Minglie; Wang, Chingyue [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Lan, Bei; Cao, Youjia [Key Laboratory of Microbial Functional Genomics of Ministry of Education, College of Life Sciences, Nankai University, Tianjin (China); He, Hao, E-mail: haohe@tju.edu.cn [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Med-X Research Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai (China)

    2014-10-27

    For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca{sup 2+} dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

  10. Lifespan extension by suppression of autophagy genes in Caenorhabditis elegans.

    Science.gov (United States)

    Hashimoto, Yasufumi; Ookuma, Sadatsugu; Nishida, Eisuke

    2009-06-01

    Lifespan is regulated by a complex combination of environmental and genetic factors. Autophagy, which is a bulk degradation system of macromolecules and organelles, has an important role in various biological events. In Caenorhabditis elegans, several autophagy genes have been shown to have a role in promoting longevity, but many other autophagy genes have not been examined for their role in the lifespan regulation. Here we have systematically examined the effect of RNAi suppression of 14 autophagy genes on lifespan. While maternal RNAi of autophagy genes in wild-type worms tended to reduce lifespan, maternal RNAi of each of seven autophagy genes in the insulin/IGF-1 receptor daf-2 mutants extended lifespan. Remarkably, RNAi of unc-51/atg-1, bec-1/atg-6 or atg-9, from young adult, i.e. after development, extended lifespan in both wild-type animals and daf-2 mutants, although RNAi of one or two genes shortened it. Moreover, our analysis suggests that the lifespan extension, which is induced by RNAi of unc-51, bec-1 or atg-9 after development, does not require the transcription factor daf-16, the NAD(+)-dependent protein deacetylase sir-2.1 or the genes related to mitochondrial functions. Collectively, our results suggest that autophagy may not always be beneficial to longevity, but may also function to restrict lifespan in C. elegans.

  11. Basal autophagy protects cardiomyocytes from doxorubicin-induced toxicity.

    Science.gov (United States)

    Pizarro, Marcela; Troncoso, Rodrigo; Martínez, Gonzalo J; Chiong, Mario; Castro, Pablo F; Lavandero, Sergio

    2016-08-31

    Doxorubicin (Doxo) is one of the most effective anti-neoplastic agents but its cardiotoxicity has been an important clinical limitation. The major mechanism of Doxo-induced cardiotoxicity is associated to its oxidative capacity. However, other processes are also involved with significant consequences for the cardiomyocyte. In recent years, a number of studies have investigated the role of autophagy on Doxo-induced cardiotoxicity but to date it is not clear how Doxo alters that process and its consequence on cardiomyocytes viability. Here we investigated the effect of Doxo 1uM for 24h of stimulation on cultured neonatal rat cardiomyocytes. We showed that Doxo inhibits basal autophagy. This inhibition is due to both Akt/mTOR signaling pathway activation and Beclin 1 level decrease. To assess the role of autophagy on Doxo-induced cardiomyocyte death, we evaluated the effects 3-methyladenine (3-MA), bafilomycin A1 (BafA), siRNA Beclin 1 (siBeclin 1) and rapamycin (Rapa) on cell viability. Inhibition of autophagy with 3-MA, BafA and siBeclin 1 increased lactate dehydrogenase (LDH) release but, when autophagy was induced by Rapa, Doxo-induced cardiomyocyte death was decreased. These results suggest that Doxo inhibits basal autophagy and contributes to cardiomyocyte death. Activation of autophagy could be used as a strategy to protect the heart against Doxo toxicity.

  12. Nanomaterials and Autophagy: New Insights in Cancer Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Panzarini, Elisa; Inguscio, Valentina; Tenuzzo, Bernardetta Anna; Carata, Elisabetta; Dini, Luciana, E-mail: luciana.dini@unisalento.it [Department of Biological and Environmental Science and Technology (Di.S.Te.B.A.), University of Salento, Lecce 73100 (Italy)

    2013-03-21

    Autophagy represents a cell’s response to stress. It is an evolutionarily conserved process with diversified roles. Indeed, it controls intracellular homeostasis by degradation and/or recycling intracellular metabolic material, supplies energy, provides nutrients, eliminates cytotoxic materials and damaged proteins and organelles. Moreover, autophagy is involved in several diseases. Recent evidences support a relationship between several classes of nanomaterials and autophagy perturbation, both induction and blockade, in many biological models. In fact, the autophagic mechanism represents a common cellular response to nanomaterials. On the other hand, the dynamic nature of autophagy in cancer biology is an intriguing approach for cancer therapeutics, since during tumour development and therapy, autophagy has been reported to trigger both an early cell survival and a late cell death. The use of nanomaterials in cancer treatment to deliver chemotherapeutic drugs and target tumours is well known. Recently, autophagy modulation mediated by nanomaterials has become an appealing notion in nanomedicine therapeutics, since it can be exploited as adjuvant in chemotherapy or in the development of cancer vaccines or as a potential anti-cancer agent. Herein, we summarize the effects of nanomaterials on autophagic processes in cancer, also considering the therapeutic outcome of synergism between nanomaterials and autophagy to improve existing cancer therapies.

  13. The Regulation of Autophagy by Influenza A Virus

    Directory of Open Access Journals (Sweden)

    Rong Zhang

    2014-01-01

    Full Text Available Influenza A virus is a dreadful pathogen of animals and humans, causing widespread infection and severe morbidity and mortality. It is essential to characterize the influenza A virus-host interaction and develop efficient counter measures against the viral infection. Autophagy is known as a catabolic process for the recycling of the cytoplasmic macromolecules. Recently, it has been shown that autophagy is a critical mechanism underlying the interaction between influenza A virus and its host. Autophagy can be induced by the infection with influenza A virus, which is considered as a necessary process for the viral proliferation, including the accumulation of viral elements during the replication of influenza A virus. On the other hand, influenza A virus can inhibit the autophagic formation via interaction with the autophagy-related genes (Atg and signaling pathways. In addition, autophagy is involved in the influenza virus-regulated cell deaths, leading to significant changes in host apoptosis. Interestingly, the high pathogenic strains of influenza A virus, such as H5N1, stimulate autophagic cell death and appear to interplay with the autophagy in distinct ways as compared with low pathogenic strains. This review discusses the regulation of autophagy, an influenza A virus driven process.

  14. TOR-dependent post-transcriptional regulation of autophagy.

    Science.gov (United States)

    Hu, Guowu; McQuiston, Travis; Bernard, Amélie; Park, Yoon-Dong; Qiu, Jin; Vural, Ali; Zhang, Nannan; Waterman, Scott R; Blewett, Nathan H; Myers, Timothy G; Maraia, Richard J; Kehrl, John H; Uzel, Gulbu; Klionsky, Daniel J; Williamson, Peter R

    2015-01-01

    Regulation of autophagy is required to maintain cellular equilibrium and prevent disease. While extensive study of post-translational mechanisms has yielded important insights into autophagy induction, less is known about post-transcriptional mechanisms that could potentiate homeostatic control. In our study, we showed that the RNA-binding protein, Dhh1 in Saccharomyces cerevisiae and Vad1 in the pathogenic yeast Cryptococcus neoformans is involved in recruitment and degradation of key autophagy mRNAs. In addition, phosphorylation of the decapping protein Dcp2 by the target of rapamycin (TOR), facilitates decapping and degradation of autophagy-related mRNAs, resulting in repression of autophagy under nutrient-replete conditions. The post-transcriptional regulatory process is conserved in both mouse and human cells and plays a role in autophagy-related modulation of the inflammasome product IL1B. These results were then applied to provide mechanistic insight into autoimmunity of a patient with a PIK3CD/p110δ gain-of-function mutation. These results thus identify an important new post-transcriptional mechanism of autophagy regulation that is highly conserved between yeast and mammals.

  15. YY1-MIR372-SQSTM1 regulatory axis in autophagy.

    Science.gov (United States)

    Feng, Lifeng; Ma, Yanning; Sun, Jie; Shen, Qi; Liu, Leiming; Lu, Haiqi; Wang, Faliang; Yue, Yongfang; Li, Jiaqiu; Zhang, Shenjie; Lin, Xiaoying; Chu, Jue; Han, Weidong; Wang, Xian; Jin, Hongchuan

    2014-08-01

    Autophagy is a self-proteolytic process that degrades intracellular material to enable cellular survival under unfavorable conditions. However, how autophagy is activated in human carcinogenesis remains largely unknown. Herein we report an epigenetic regulation of autophagy in human cancer cells. YY1 (YY1 transcription factor) is a well-known epigenetic regulator and is upregulated in many cancers. We found that YY1 knockdown inhibited cell viability and autophagy flux through downregulating SQSTM1 (sequestosome 1). YY1 regulated SQSTM1 expression through the epigenetic modulation of the transcription of MIR372 (microRNA 372) which was found to target SQSTM1 directly. During nutrient starvation, YY1 was stimulated to promote SQSTM1 expression and subsequent autophagy activation by suppressing MIR372 expression. Similar to YY1 depletion, MIR372 overexpression blocked autophagy activation and inhibited in vivo tumor growth. SQSTM1 upregulation and competent autophagy flux thus contributed to the oncogenic function of YY1. YY1-promoted SQSTM1 upregulation might be a useful histological marker for cancer detection and a potential target for drug development.

  16. Autophagy in the immune response to tuberculosis: clinical perspectives.

    LENUS (Irish Health Repository)

    Ní Cheallaigh, C

    2011-06-01

    A growing body of evidence points to autophagy as an essential component in the immune response to tuberculosis. Autophagy is a direct mechanism of killing intracellular Mycobacterium tuberculosis and also acts as a modulator of proinflammatory cytokine secretion. In addition, autophagy plays a key role in antigen processing and presentation. Autophagy is modulated by cytokines; it is stimulated by T helper type 1 (Th1) cytokines such as tumour necrosis factor (TNF)-α and interferon (IFN)-γ, and is inhibited by the Th2 cytokines interleukin (IL)-4 and IL-13 and the anti-inflammatory cytokine IL-10. Vitamin D, via cathelicidin, can also induce autophagy, as can Toll-like receptor (TLR)-mediated signals. Autophagy-promoting agents, administered either locally to the lungs or systemically, could have a clinical application as adjunctive treatment of drug-resistant and drug-sensitive tuberculosis. Moreover, vaccines which effectively induce autophagy could be more successful in preventing acquisition or reactivation of latent tuberculosis.

  17. The inositol trisphosphate receptor in the control of autophagy.

    Science.gov (United States)

    Criollo, Alfredo; Vicencio, José Miguel; Tasdemir, Ezgi; Maiuri, M Chiara; Lavandero, Sergio; Kroemer, Guido

    2007-01-01

    The second messenger myo-inositol-1,4,5-trisphosphate (IP(3)) acts on the IP(3) receptor (IP(3)R), an IP(3)-activated Ca(2+) channel of the endoplasmic reticulum (ER). The IP(3)R agonist IP(3) inhibits starvation-induced autophagy. The IP(3)R antagonist xestospongin B induces autophagy in human cells through a pathway that requires the obligate contribution of Beclin-1, Atg5, Atg10, Atg12 and hVps34, yet is inhibited by ER-targeted Bcl-2 or Bcl-XL, two proteins that physically interact with IP(3)R. Autophagy can also be induced by depletion of the IP(3)R by small interfering RNAs. Autophagy induction by IP(3)R blockade cannot be explained by changes in steady state levels of Ca(2+) in the endoplasmic reticulum (ER) and the cytosol. Autophagy induction by IP(3)R blockade is effective in cells lacking the obligate mediator of ER stress IRE1. In contrast, IRE1 is required for autophagy induced by ER stress-inducing agents such a tunicamycin or thapsigargin. These findings suggest that there are several distinct pathways through which autophagy can be initiated at the level of the ER.

  18. The IKK complex contributes to the induction of autophagy.

    Science.gov (United States)

    Criollo, Alfredo; Senovilla, Laura; Authier, Hélène; Maiuri, Maria Chiara; Morselli, Eugenia; Vitale, Ilio; Kepp, Oliver; Tasdemir, Ezgi; Galluzzi, Lorenzo; Shen, Shensi; Tailler, Maximilien; Delahaye, Nicolas; Tesniere, Antoine; De Stefano, Daniela; Younes, Aména Ben; Harper, Francis; Pierron, Gérard; Lavandero, Sergio; Zitvogel, Laurence; Israel, Alain; Baud, Véronique; Kroemer, Guido

    2010-02-03

    In response to stress, cells start transcriptional and transcription-independent programs that can lead to adaptation or death. Here, we show that multiple inducers of autophagy, including nutrient depletion, trigger the activation of the IKK (IkappaB kinase) complex that is best known for its essential role in the activation of the transcription factor NF-kappaB by stress. Constitutively active IKK subunits stimulated autophagy and transduced multiple signals that operate in starvation-induced autophagy, including the phosphorylation of AMPK and JNK1. Genetic inhibition of the nuclear translocation of NF-kappaB or ablation of the p65/RelA NF-kappaB subunit failed to suppress IKK-induced autophagy, indicating that IKK can promote the autophagic pathway in an NF-kappaB-independent manner. In murine and human cells, knockout and/or knockdown of IKK subunits (but not that of p65) prevented the induction of autophagy in response to multiple stimuli. Moreover, the knockout of IKK-beta suppressed the activation of autophagy by food deprivation or rapamycin injections in vivo, in mice. Altogether, these results indicate that IKK has a cardinal role in the stimulation of autophagy by physiological and pharmacological stimuli.

  19. Emerging role of autophagy in pediatric neurodegenerative and neurometabolic diseases.

    Science.gov (United States)

    Ebrahimi-Fakhari, Darius; Wahlster, Lara; Hoffmann, Georg F; Kölker, Stefan

    2014-01-01

    Pediatric neurodegenerative diseases are a heterogeneous group of diseases that result from specific genetic and biochemical defects. In recent years, studies have revealed a wide spectrum of abnormal cellular functions that include impaired proteolysis, abnormal lipid trafficking, accumulation of lysosomal content, and mitochondrial dysfunction. Within neurons, elaborated degradation pathways such as the ubiquitin-proteasome system and the autophagy-lysosomal pathway are critical for maintaining homeostasis and normal cell function. Recent evidence suggests a pivotal role for autophagy in major adult and pediatric neurodegenerative diseases. We herein review genetic, pathological, and molecular evidence for the emerging link between autophagy dysfunction and lysosomal storage disorders such as Niemann-Pick type C, progressive myoclonic epilepsies such as Lafora disease, and leukodystrophies such as Alexander disease. We also discuss the recent discovery of genetically deranged autophagy in Vici syndrome, a multisystem disorder, and the implications for the role of autophagy in development and disease. Deciphering the exact mechanism by which autophagy contributes to disease pathology may open novel therapeutic avenues to treat neurodegeneration. To this end, an outlook on novel therapeutic approaches targeting autophagy concludes this review.

  20. Haematuria as a risk factor for chronic kidney disease progression in glomerular diseases: A review.

    Science.gov (United States)

    Moreno, Juan Antonio; Yuste, Claudia; Gutiérrez, Eduardo; Sevillano, Ángel M; Rubio-Navarro, Alfonso; Amaro-Villalobos, Juan Manuel; Praga, Manuel; Egido, Jesús

    2016-04-01

    Haematuria has long been considered to be a benign condition associated with glomerular diseases. However, new evidences suggest that haematuria has a pathogenic role in promoting kidney disease progression. An increased risk for end-stage renal disease has been reported in adolescents and young adults with persistent microscopic haematuria. A persistent impairment of renal function has been also reported following macroscopic haematuria-associated acute kidney injury in immunoglobulin A nephropathy. Haematuria-induced renal damage has been related to oxidant, cytotoxic and inflammatory effects induced by haemoglobin or haem released from red blood cells. The pathophysiological origin of haematuria may be due to a more fragile and easily ruptured glomerular filtration barrier, as reported in several glomerular diseases. In this review we describe a number of the key issues associated with the epidemiology and pathogenesis of haematuria-associated diseases, provide an update of recent knowledge on the role of haematuria on renal function outcome and discuss specific therapeutic approaches in this setting. KEY SUMMARY POINTS: 1. Glomerular haematuria is a common observation in a number of renal diseases that may lead to persistent renal injury. 2. Haematuria in children differs from that in adults in specific aspects, particularly in the frequency of glomerular diseases and renal disease outcome. 3. Regular follow-up of renal function in children with isolated microhaematuria may be recommended.

  1. Pathogenesis of common glomerular diseases – role of the podocyte cytoskeleton

    Directory of Open Access Journals (Sweden)

    Kumagai T

    2012-10-01

    Full Text Available Takanori Kumagai, Flaviana Mouawad, Tomoko TakanoDepartment of Medicine, McGill University Health Centre, Montreal, Quebec, CanadaAbstract: Glomerulus is the filtration unit of the kidney where the first step of urine formation takes place. In the glomerulus, water and small molecules including waste products of the body are filtered into the urine, while large molecules essential for body function such as albumin are retained. When this barrier function of the kidney is impaired, protein leakage into the urine (proteinuria occurs. Proteinuria is not only a hallmark of many glomerular diseases but also a prognostic marker of kidney disease progression. Visceral glomerular epithelial cells (commonly called podocytes are known to have an important role in the maintenance of glomerular barrier function. In the last decade, remarkable progress has been made in podocyte biology, mainly led by the discoveries of important proteins that work together to maintain the intricate morphology and function of podocytes. Most of these so-called podocyte proteins modulate the actin cytoskeleton either directly or indirectly. The aim of the current review is to discuss the pathogenesis of common glomerular diseases with a particular focus on the role of the actin cytoskeleton in podocytes. The diseases covered include minimal change disease, focal segmental glomerulosclerosis (idiopathic and hereditary, membranous nephropathy, hypertensive glomerulosclerosis, and diabetic nephropathy.Keywords: glomerular disease, podocyte, cytoskeleton, proteinuria

  2. Pattern of glomerular diseases in oman: A study based on light microscopy and immunofluorescence

    Directory of Open Access Journals (Sweden)

    Nasar Yousuf Alwahaibi

    2013-01-01

    Full Text Available Light microscopy and immunofluorescence play an important part in the final diagnosis of renal biopsy. The aim of this study was to analyze the pattern of various glomerular diseases in Oman. A total of 424 renal biopsies were retrospectively analyzed at the Sultan Qaboos University Hospital between 1999 and 2010. Focal and segmental glomerulosclerosis (FSGS, minimal change disease (MCD, membranous glomerulopathy (MGN and IgA nephropathy were the most common primary glomerular diseases encountered, accounting for 21.2%, 17%, 12.3% and 8.3%, respectively, of all cases. Lupus nephritis was the most common secondary glomerular disease and was the most prevalent among all biopsies, accounting for 30.4% of all biopsies. Amyloidosis was seen in only two cases. The presence of fluorescein isothiocyanatefibrin in all renal cases was low when compared with IgG, IgA, IgM, C3 and C1q markers. In conclusion, based on the findings of this study, lupus nephritis was the most common of all glomerular diseases and FSGS was the most common primary glomerular disease. The importance of fluorescein isothiocyanate-fibrin in the diagnosis of renal biopsy needs to be further investigated.

  3. Glomerular Disease Associated with Takayasu Arteritis:6 Cases Analysis and Review of the Literature

    Institute of Scientific and Technical Information of China (English)

    Xue-mei Li; Wen-ling Ye; Yu-bing Wen; Hang Li; Li-meng Chen; Dong-yan Liu; Xue-jun Zeng; Xue-wang Li

    2009-01-01

    To evaluate the clinical features, renal histopathology and therapeutic response to glucocorticoid and immunosuppressive agents in patients with glomerular disease associated with Takayasu arteritis (TA).Methods Patients with TA and renal biopsy-confirmed glomerular disease were investigated retrospectively. None of them had renal artery stenosis or occlusive changes.Results Six patients with glomerulopathy, accounting for 3.75% of the 160 TA patients admitted to our hospital at the same period, were analyzed. All of them were females with a mean age of 35.5 ± 10.0 years. Four cases presented with lower extremity edema. Laboratory tests showed that one was nephrotic syndrome, three were nephrotic range proteinuria, and two of them had mild renal dysfunction. The other two patients were asymptomatic microscopic hematuria and proteinuria. Renal pathology revealed mild immunoglobulin A nephropathy in two cases, mild mesangial proliferative glomerulonephritis (GN),membranoproliferative GN, minimal change disease, and fibrillary GN in one case respectively. Five cases received glucocorticoids and cyclophosphamide therapy. Proteinuria and microscopic hematuria disappeared in 2 to 4 weeks after the initiation of therapy in three cases. The patient with membranoproliferative GN also reached complete remission of proteinuria and recovered renal function 6 months after the treatment.Conclusions TA may induce glomerular disease as a part of its histological spectrum. Apart from ischemic glomerular disease, glomerular disease should be suspected when TA patients have microscopic hematuria or proteinuria, that may be therapeutically responsive to glucocorticoids and immunosuppressive agent in relative early phase.

  4. Nephritogenic lupus antibodies recognize glomerular basement membrane-associated chromatin fragments released from apoptotic intraglomerular cells.

    Science.gov (United States)

    Kalaaji, Manar; Mortensen, Elin; Jørgensen, Leif; Olsen, Randi; Rekvig, Ole Petter

    2006-06-01

    Antibodies to dsDNA represent a classification criterion for systemic lupus erythematosus. Subpopulations of these antibodies are involved in lupus nephritis. No known marker separates nephritogenic from non-nephritogenic anti-dsDNA antibodies. It is not clear whether specificity for glomerular target antigens or intrinsic antibody-affinity for dsDNA or nucleosomes is a critical parameter. Furthermore, it is still controversial whether glomerular target antigen(s) is constituted by nucleosomes or by non-nucleosomal glomerular structures. Previously, we have demonstrated that antibodies eluted from murine nephritic kidneys recognize nucleosomes, but not other glomerular antigens. In this study, we determined the structures that bind nephritogenic autoantibodies in vivo by transmission electron microscopy, immune electron microscopy, and colocalization immune electron microscopy using experimental antibodies to dsDNA, to histones and transcription factors, or to laminin. The data obtained are consistent and point at glomerular basement membrane-associated nucleosomes as target structures for the nephritogenic autoantibodies. Terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling or caspase-3 assays demonstrate that lupus nephritis is linked to intraglomerular cell apoptosis. The data suggest that nucleosomes are released by apoptosis and associate with glomerulus basement membranes, which may then be targeted by pathogenic anti-nucleosome antibodies. Thus, apoptotic nucleosomes may represent both inducer and target structures for nephritogenic autoantibodies in systemic lupus erythematosus.

  5. Autophagy contributes to gefitinib-induced glioma cell growth inhibition

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    Chang, Cheng-Yi [Department of Surgery, Fong-Yuan Hospital, Taichung 420, Taiwan (China); Graduate Institute of Pharmaceutical Science and Technology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan (China); Kuan, Yu-Hsiang [Department of Pharmacology, School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Pharmacy, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); Ou, Yen-Chuan; Li, Jian-Ri [Division of Urology, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Wu, Chih-Cheng [Department of Anesthesiology, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Department of Financial and Computational Mathematics, Providence University, Taichung 433, Taiwan (China); Pan, Pin-Ho [Department of Pediatrics, Tungs’ Taichung MetroHarbor Hospital, Taichung 435, Taiwan (China); Chen, Wen-Ying [Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan (China); Huang, Hsuan-Yi [Department of Surgery, Fong-Yuan Hospital, Taichung 420, Taiwan (China); Chen, Chun-Jung, E-mail: cjchen@vghtc.gov.tw [Department of Medical Research, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Institute of Biomedical Sciences, National Chung Hsing University, Taichung 402, Taiwan (China); Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan (China); Center for General Education, Tunghai University, Taichung 407, Taiwan (China); Department of Nursing, HungKuang University, Taichung 433, Taiwan (China)

    2014-09-10

    Epidermal growth factor receptor tyrosine kinase inhibitors, including gefitinib, have been evaluated in patients with malignant gliomas. However, the molecular mechanisms involved in gefitinib-mediated anticancer effects against glioma are incompletely understood. In the present study, the cytostatic potential of gefitinib was demonstrated by the inhibition of glioma cell growth, long-term clonogenic survival, and xenograft tumor growth. The cytostatic consequences were accompanied by autophagy, as evidenced by monodansylcadaverine staining of acidic vesicle formation, conversion of microtubule-associated protein-1 light chain 3-II (LC3-II), degradation of p62, punctate pattern of GFP-LC3, and conversion of GFP-LC3 to cleaved-GFP. Autophagy inhibitor 3-methyladenosine and chloroquine and genetic silencing of LC3 or Beclin 1 attenuated gefitinib-induced growth inhibition. Gefitinib-induced autophagy was not accompanied by the disruption of the Akt/mammalian target of rapamycin signaling. Instead, the activation of liver kinase-B1/AMP-activated protein kinase (AMPK) signaling correlated well with the induction of autophagy and growth inhibition caused by gefitinib. Silencing of AMPK suppressed gefitinib-induced autophagy and growth inhibition. The crucial role of AMPK activation in inducing glioma autophagy and growth inhibition was further supported by the actions of AMP mimetic AICAR. Gefitinib was shown to be capable of reducing the proliferation of glioma cells, presumably by autophagic mechanisms involving AMPK activation. - Highlights: • Gefitinib causes cytotoxic and cytostatic effect on glioma. • Gefitinib induces autophagy. • Gefitinib causes cytostatic effect through autophagy. • Gefitinib induces autophagy involving AMPK.

  6. Autophagy Is an Innate Mechanism Associated with Leprosy Polarization

    Science.gov (United States)

    Andrade, Priscila Ribeiro; Ferreira, Helen; Nery, José Augusto da Costa; Côrte-Real, Suzana; da Silva, Gilberto Marcelo Sperandio; Rosa, Patricia Sammarco; Fabri, Mario; Sarno, Euzenir Nunes

    2017-01-01

    Leprosy is a chronic infectious disease that may present different clinical forms according to the immune response of the host. Levels of IFN-γ are significantly raised in paucibacillary tuberculoid (T-lep) when compared with multibacillary lepromatous (L-lep) patients. IFN-γ primes macrophages for inflammatory activation and induces the autophagy antimicrobial mechanism. The involvement of autophagy in the immune response against Mycobacterium leprae remains unexplored. Here, we demonstrated by different autophagic assays that LC3-positive autophagosomes were predominantly observed in T-lep when compared with L-lep lesions and skin-derived macrophages. Accumulation of the autophagic receptors SQSTM1/p62 and NBR1, expression of lysosomal antimicrobial peptides and colocalization analysis of autolysosomes revealed an impairment of the autophagic flux in L-lep cells, which was restored by IFN-γ or rapamycin treatment. Autophagy PCR array gene-expression analysis revealed a significantly upregulation of autophagy genes (BECN1, GPSM3, ATG14, APOL1, and TPR) in T-lep cells. Furthermore, an upregulation of autophagy genes (TPR, GFI1B and GNAI3) as well as LC3 levels was observed in cells of L-lep patients that developed type 1 reaction (T1R) episodes, an acute inflammatory condition associated with increased IFN-γ levels. Finally, we observed increased BCL2 expression in L-lep cells that could be responsible for the blockage of BECN1-mediated autophagy. In addition, in vitro studies demonstrated that dead, but not live M. leprae can induce autophagy in primary and lineage human monocytes, and that live mycobacteria can reduce the autophagy activation triggered by dead mycobacteria, suggesting that M. leprae may hamper the autophagic machinery as an immune escape mechanism. Together, these results indicate that autophagy is an important innate mechanism associated with the M. leprae control in skin macrophages. PMID:28056107

  7. Applicability of estimating glomerular filtration rate equations in pediatric patients: comparison with a measured glomerular filtration rate by iohexol clearance.

    Science.gov (United States)

    Deng, Fang; Finer, Gal; Haymond, Shannon; Brooks, Ellen; Langman, Craig B

    2015-03-01

    Estimating glomerular filtration rate (eGFR) has become popular in clinical medicine as an alternative to measured GFR (mGFR), but there are few studies comparing them in clinical practice. We determined mGFR by iohexol clearance in 81 consecutive children in routine practice and calculated eGFR from 14 standard equations using serum creatinine, cystatin C, and urea nitrogen that were collected at the time of the mGFR procedure. Nonparametric Wilcoxon test, Spearman correlation, Bland-Altman analysis, bias (median difference), and accuracy (P15, P30) were used to compare mGFR with eGFR. For the entire study group, the mGFR was 77.9 ± 38.8 mL/min/1.73 m(2). Eight of the 14 estimating equations demonstrated values without a significant difference from the mGFR value and demonstrated a lower bias in Bland-Altman analysis. Three of these 8 equations based on a combination of creatinine and cystatin C (Schwartz et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol 2009;20:629-37; Schwartz et al. Improved equations estimating GFR in children with chronic kidney disease using an immunonephelometric determination of cystatin C. Kidney Int 2012;82:445-53; Chehade et al. New combined serum creatinine and cystatin C quadratic formula for GFR assessment in children. Clin J Am Soc Nephrol 2014;9:54-63) had the highest accuracy with approximately 60% of P15 and 80% of P30. In 10 patients with a single kidney, 7 with kidney transplant, and 11 additional children with short stature, values of the 3 equations had low bias and no significant difference when compared with mGFR. In conclusion, the 3 equations that used cystatin C, creatinine, and growth parameters performed in a superior manner over univariate equations based on either creatinine or cystatin C and also had good applicability in specific pediatric patients with single kidneys, those with a kidney transplant, and short stature. Thus, we suggest that eGFR calculations in pediatric clinical practice

  8. Autophagy and immunity – insights from human herpesviruses

    Directory of Open Access Journals (Sweden)

    Luke eWilliams

    2012-07-01

    Full Text Available The herpesviruses are a family of double-stranded DNA viruses that infect a large variety of organisms. Having co-evolved with their hosts over millennia, herpesviruses have developed a large repertoire of mechanisms to manipulate normal cellular processes. Given the important role of autophagy in cells, this pathway is a target for manipulation by herpesviruses. Here we describe the ways that human herpesviruses interact and interfere with the cellular autophagy machinery in order to escape innate and adaptive immunity. Recent research on the human herpesvirus Epstein-Barr Virus (EBV suggesting that localisation within the nucleus can shelter viral proteins from autophagy is also discussed.

  9. Alternative autophagy, brefeldin A and viral trafficking pathways

    Science.gov (United States)

    Grose, Charles; Klionsky, Daniel J.

    2016-01-01

    ABSTRACT Two topics that have attracted recent attention in the field of autophagy concern the source of the membrane that is used to form the autophagosome during macroautophagy and the role of noncanonical autophagic pathways. The 2 topics may converge when considering the intersection of autophagy with viral infection. We suggest that noncanonical autophagy, which is sensitive to treatment with brefeldin A, may converge with the infectious cycles of certain DNA and RNA viruses that utilize membrane from the ER and cis-Golgi. PMID:27439673

  10. Role of autophagy in acute myeloid leukemia therapy

    Institute of Scientific and Technical Information of China (English)

    Su-Ping Zhang; Yu-Na Niu; Na Yuan; Ai-Hong Zhang; Dan Chao; Qiu-Ping Xu; Li-Jun Wang

    2013-01-01

    Despite its dual role in determining cell fate in a wide array of solid cancer cell lines,autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion protein that drives leukemogenesis.However,autophagy also induces the demise of acute leukemia cells that do not express the known fusion protein,though the molecular mechanism remains elusive.Nevertheless,since it can induce cooperation with apoptosis and differentiation in response to autophagic signals,autophagy can be manipulated for a better therapy on acute myeloid leukemia.

  11. The protective roles of autophagy in ischemic preconditioning

    Institute of Scientific and Technical Information of China (English)

    Wen-jun YAN; Hai-long DONG; Li-ze XIONG

    2013-01-01

    Autophagy,a process for the degradation of protein aggregates and dysfunctional organelles,is required for cellular homeostasis and cell survival in response to stress and is implicated in endogenous protection.Ischemic preconditioning is a brief and nonlethal episode of ischemia,confers protection against subsequent ischemia-repenfusion through the up-regulation of endogenous protective mechanisms.Emerging evidence shows that autophagy is associated with the protective effect of ischemic preconditioning.This review summarizes recent progress in research on the functions and regulations of the autophagy pathway in preconditioning-induced protection and cellular survival.

  12. Regulation of autophagy by some natural products as a potential therapeutic strategy for cardiovascular disorders.

    Science.gov (United States)

    Hashemzaei, Mahmoud; Entezari Heravi, Reza; Rezaee, Ramin; Roohbakhsh, Ali; Karimi, Gholamreza

    2017-02-24

    Autophagy is a lysosomal degradation process through which long-lived and misfolded proteins and organelles are sequestered, degraded by lysosomes, and recycled. Autophagy is an essential part of cardiomyocyte homeostasis and increases the survival of cells following cellular stress and starvation. Recent studies made clear that dysregulation of autophagy in the cardiovascular system leads to heart hypertrophy and failure. In this manner, autophagy seems to be an attractive target in the new treatment of cardiovascular diseases. Although limited activation of autophagy is generally considered to be cardioprotective, excessive autophagy leads to cell death and cardiac atrophy. Natural products such as resveratrol, berberine, and curcumin that are present in our diet, can trigger autophagy via canonical (Beclin-1-dependent) and non-canonical (Beclin-1-independent) pathways. The autophagy-modifying capacity of these compounds should be taken into consideration for designing novel therapeutic agents. This review focuses on the role of autophagy in the cardioprotective effects of these compounds.

  13. Spermidine and resveratrol induce autophagy by distinct pathways converging on the acetylproteome.

    Science.gov (United States)

    Morselli, Eugenia; Mariño, Guillermo; Bennetzen, Martin V; Eisenberg, Tobias; Megalou, Evgenia; Schroeder, Sabrina; Cabrera, Sandra; Bénit, Paule; Rustin, Pierre; Criollo, Alfredo; Kepp, Oliver; Galluzzi, Lorenzo; Shen, Shensi; Malik, Shoaib Ahmad; Maiuri, Maria Chiara; Horio, Yoshiyuki; López-Otín, Carlos; Andersen, Jens S; Tavernarakis, Nektarios; Madeo, Frank; Kroemer, Guido

    2011-02-21

    Autophagy protects organelles, cells, and organisms against several stress conditions. Induction of autophagy by resveratrol requires the nicotinamide adenine dinucleotide-dependent deacetylase sirtuin 1 (SIRT1). In this paper, we show that the acetylase inhibitor spermidine stimulates autophagy independent of SIRT1 in human and yeast cells as well as in nematodes. Although resveratrol and spermidine ignite autophagy through distinct mechanisms, these compounds stimulate convergent pathways that culminate in concordant modifications of the acetylproteome. Both agents favor convergent deacetylation and acetylation reactions in the cytosol and in the nucleus, respectively. Both resveratrol and spermidine were able to induce autophagy in cytoplasts (enucleated cells). Moreover, a cytoplasm-restricted mutant of SIRT1 could stimulate autophagy, suggesting that cytoplasmic deacetylation reactions dictate the autophagic cascade. At doses at which neither resveratrol nor spermidine stimulated autophagy alone, these agents synergistically induced autophagy. Altogether, these data underscore the importance of an autophagy regulatory network of antagonistic deacetylases and acetylases that can be pharmacologically manipulated.

  14. ER stress, autophagy, and RNA viruses

    Directory of Open Access Journals (Sweden)

    Jia-Rong eJheng

    2014-08-01

    Full Text Available Endoplasmic reticulum (ER stress is a general term for representing the pathway by which various stimuli affect ER functions. ER stress induces the evolutionarily conserved signaling pathways, called the unfolded protein response (UPR, which compromises the stimulus and then determines whether the cell survives or dies. In recent years, ongoing research has suggested that these pathways may be linked to the autophagic response, which plays a key role in the cell’s response to various stressors. Autophagy performs a self-digestion function, and its activation protects cells against certain pathogens. However, the link between the UPR and autophagy may be more complicated. These two systems may act dependently, or the induction of one system may interfere with the other. Experimental studies have found that different viruses modulate these mechanisms to allow them to escape the host immune response or, worse, to exploit the host’s defense to their advantage; thus, this topic is a critical area in antiviral research. In this review, we summarize the current knowledge about how RNA viruses, including influenza virus, poliovirus, coxsackievirus, enterovirus 71, Japanese encephalitis virus, hepatitis C virus, and dengue virus, regulate these processes. We also discuss recent discoveries and how these will produce novel strategies for antiviral treatment.

  15. Zymophagy: Selective Autophagy of Secretory Granules

    Directory of Open Access Journals (Sweden)

    Maria I. Vaccaro

    2012-01-01

    Full Text Available Timing is everything. That's especially true when it comes to the activation of enzymes created by the pancreas to break down food. Pancreatic enzymes are packed in secretory granules as precursor molecules called zymogens. In physiological conditions, those zymogens are activated only when they reach the gut, where they get to work releasing and distributing nutrients that we need to survive. If this process fails and the enzymes are prematurely activated within the pancreatic cell, before they are released from the gland, they break down the pancreas itself causing acute pancreatitis. This is a painful disease that ranges from a mild and autolimited process to a severe and lethal condition. Recently, we demonstrated that the pancreatic acinar cell is able to switch on a refined mechanism that could explain the autolimited form of the disease. This is a novel selective form of autophagy named zymophagy, a cellular process to specifically detect and degrade secretory granules containing activated enzymes before they can digest the organ. In this work, we revise the molecules and mechanisms that mediate zymophagy, a selective autophagy of secretory granules.

  16. Nephrin Deficiency Activates NF-κB and Promotes Glomerular Injury

    Science.gov (United States)

    Hussain, Sagair; Romio, Leile; Saleem, Moin; Mathieson, Peter; Serrano, Manuel; Moscat, Jorge; Diaz-Meco, Maria; Scambler, Peter

    2009-01-01

    Increasing evidence implicates activation of NF-κB in a variety of glomerular diseases, but the mechanisms involved are unknown. Here, upregulation of NF-κB in the podocytes of transgenic mice resulted in glomerulosclerosis and proteinuria. Absence of the podocyte protein nephrin resulted in NF-κB activation, suggesting that nephrin negatively regulates the NF-κB pathway. Signal transduction assays supported a functional relationship between nephrin and NF-κB and suggested the involvement of atypical protein kinase C (aPKCζ/λ/ι) as an intermediary. We propose that disruption of the slit diaphragm leads to activation of NF-κB; subsequent upregulation of NF-κB-driven genes results in glomerular damage mediated by NF-κB-dependent pathways. In summary, nephrin may normally limit NF-κB activity in the podocyte, suggesting a mechanism by which it might discourage the evolution of glomerular disease. PMID:19497968

  17. mir-30d Regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaojun [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zhong, Xiaomin [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Tanyi, Janos L.; Shen, Jianfeng [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Xu, Congjian [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Gao, Peng [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zheng, Tim M. [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); DeMichele, Angela [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); Zhang, Lin, E-mail: linzhang@mail.med.upenn.edu [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)

    2013-02-15

    Highlights: ► Gene set enrichment analysis indicated mir-30d might regulate the autophagy pathway. ► mir-30d represses the expression of BECN1, BNIP3L, ATG12, ATG5 and ATG2. ► BECN1, BNIP3L, ATG12, ATG5 and ATG2 are direct targets of mir-30d. ► mir-30d inhibits autophagosome formation and LC3B-I conversion to LC3B-II. ► mir-30d regulates the autophagy process. -- Abstract: In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy.

  18. Variation in genes that regulate blood pressure are associated with glomerular filtration rate in Chinese.

    Directory of Open Access Journals (Sweden)

    May E Montasser

    Full Text Available Chronic kidney disease (CKD can be a consequence of diabetes, hypertension, immunologic disorders, and other exposures, as well as genetic factors that are still largely unknown. Glomerular filtration rate (GFR, which is widely used to measure kidney function, has a heritability ranging from 25% to 75%, but only 1.5% of this heritability is explained by genetic loci that have been identified to date. In this study we tested for associations between GFR and 234 SNPs in 26 genes from pathways of blood pressure regulation in 3,025 rural Chinese participants of the "Genetic Epidemiology Network of Salt Sensitivity" (GenSalt study. We estimated GFR (eGFR using baseline serum creatinine measurements obtained prior to dietary intervention. We identified significant associations between eGFR and 12 SNPs in 6 genes (ACE, ADD1, AGT, GRK4, HSD11B1, and SCNN1G. The cumulative effect of the protective alleles was an increase in mean eGFR of 4 mL/min per 1.73 m2, while the cumulative effect of the risk alleles was a decrease in mean eGFR of 3 mL/min per 1.73 m2. In addition, we identified a significant interaction between SNPs in CYP11B1 and ADRB2. We have identified common variants in genes from pathways that regulate blood pressure and influence kidney function as measured by eGFR, providing new insights into the genetic determinants of kidney function. Complex genetic effects on kidney function likely involve interactions among genes as we observed for CYP11B1 and ADRB2.

  19. Metabolic and Hormonal Determinants of Glomerular Filtration Rate and Renal Hemodynamics in Severely Obese Individuals

    Directory of Open Access Journals (Sweden)

    Edoardo Vitolo

    2016-10-01

    Full Text Available Objective: Renal function is often compromised in severe obesity. A true measurement of glomerular filtration rate (GFR is unusual, and how estimation formulae (EstForm perform in such individuals is unclear. We characterized renal function and hemodynamics in severely obese individuals, assessing the reliability of EstForm. Methods: We measured GFR (mGFR by iohexol plasma clearance, renal plasma flow (RPF by 123I-ortho-iodo-hippurate, basal and stimulated vascular renal indices, endothelium-dependent and -independent vasodilation using flow-mediated dilation (FMD as well as metabolic and hormonal profile in morbid, otherwise healthy, obese subjects. Results: Compared with mGFR, the better performing EstForm was CKD-EPI (5.3 ml/min/1.73 m2 bias by Bland-Altman analysis. mGFR was directly related with RPF, total and incremental glucose AUC, and inversely with PTH and h8 cortisol. Patients with mGFR below the median shown significantly higher PTH and lower vitamin D3. Basal or dynamic renal resistive index, FMD, pulse wave velocity were not related with mGFR. In an adjusted regression model, renal diameter and plasma flow remained related with mGFR (R2 = 0.67, accounting for 15% and 21% of mGFR variance, respectively. Conclusions: CKD-EPI formula should be preferred in morbid obesity; glucose increments during oral glucose tolerance test correlate with hyperfiltration; RPF and diameter are independent determinants of mGFR; slightly high PTH values, frequent in obesity, might influence mGFR.

  20. Effect of Cisplatin on Glomerular Filtration Rate and Effective Renal Plasma Flow

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sang Moo; Hong, Sung Woon; Kim, Young Hyun; Hong, Weon Seon; Song, Jae Kwan; Kim, Young Whan; Lee, Jhin Oh; Kang, Tae Woong [Korea Cancer Canter Hospital, Seoul (Korea, Republic of)

    1989-03-15

    While cisplatin has been widely used in the treatment of a variety of cancers, nephrotoxicity is one of the major problems which frequently limit clinical usefulness of cisplatin. This study has been conducted to investigate nephrotoxicity of cisplatin in terms of changes in glomerular filtration rate (GFR) and effective renal plasma flow (EFPF) measured by the simultaneous use of {sup 99m}Tc-DTPP and {sup 131}I-OIH, before and after administration of cisplatin, in 12 patients with lung cancer and four patients with esophageal cancer. Cisplatin was administrated at total doses of 75-100 mg/m{sup 2} with two hour hydration and diuresis method. GFR determined by the use of {sup 99m}Tc-DTPA had a good correlation with 24-hour creatinine clearance rate (r=0.77, p<0.001). GFR and filtration fraction decreased immediately after administration of cisplatin, however, they showed a tendency to be in completely recovered four weeks after administration. ERPF was not changed immediately after and four weeks after administration of cisplatin. GFR before and immediately after administration of cisplatin were analyzed with regard to age, sex, performance status, previous administration of cisplatin and method of administration. None of these factors had any influence on the rate of decrease in GFR except method of administration. Administration of cisplatin as a single dose lowered GFR more compared with that as divided doses. In this study, we have also demonstrated that the simultaneous use of {sup 99m}Tc-DTPA and {sup 131}I-OIH was a useful tool for the measurement of GFR and ERPF respectively.

  1. Autophagy and Cancer Treatment%细胞自噬与肿瘤发生

    Institute of Scientific and Technical Information of China (English)

    相建峰; 林盛明; 相燕洁; 张闽光

    2012-01-01

    Autophagy is widely exist in eukaryotic cells, the phenomenon of life, is an important body defense and protection mechanisms. Cells can through the autophagy and the lysosome, eliminate,degradation,digestivedamage,degeneration,aging and lose function of cells,organelles,denatured protein and nucleic acid and biological macromolecules,for the reconstruction of the cells, regeneration and repair provide the necessary raw materials, achieve cell recycling and reuse. Autophagy abnormalities and tumors development is closely related to the tumor process involving multiple levels of influence,including oncogenes,cell cycle, angiogenesis and lysosome changes,etc. Therefore,through the study of effects of autophagy,not only to further reveals tumor occurrence and development of potential mechanism, but also may provide cancer prevention and treatment of new ideas.%细胞自噬(autophagy)是广泛存在于真核细胞中的生命现象,是机体一种重要的防御和保护机制.细胞可以通过自噬和溶酶体,消除、降解、消化受损、变性、衰老和失去功能的细胞、细胞器、变性蛋白质与核酸等生物大分子,为细胞的重建、再生和修复提供必须原料,实现细胞的再循环和再利用.自噬异常与肿瘤的发生、发展密切相关,涉及影响肿瘤进程的多个层面,包括肿瘤基因,细胞周期,血管生成及溶酶体变化等.因此,通过对自噬作用的研究,既进一步揭示肿瘤发生、发展的潜在机制,也可能为肿瘤的预防和治疗提供新的思路.

  2. Role of enhanced glomerular synthesis of thromboxane A2 in progressive kidney disease.

    Science.gov (United States)

    Salvati, P; Ferti, C; Ferrario, R G; Lamberti, E; Duzzi, L; Bianchi, G; Remuzzi, G; Perico, N; Benigni, A; Braidotti, P

    1990-09-01

    Normotensive rats of the Milan strain (MNS) spontaneously develop focal glomerulosclerosis. In order to explore the contribution of glomerular thromboxane (TX) A2 synthesis to the development of the disease, we have characterized the time course of renal functional and biochemical changes, and their modification by long-term treatment with a TX-synthase inhibitor. Oral administration (150 mg.kg-1 from 1 to 14 months of age) of FCE 22178 suppressed enhanced glomerular TXB2 production at all experimental times (mean inhibition 80%) and proteinuria (varying between 27.1 and 73.0%) while preserving renal blood flow and glomerular filtration rate. These effects of TX-synthase inhibition were seen in the absence of any statistically significant changes in systemic blood pressure. Moreover, FCE 22178 had no antihypertensive effects in hypertensive rats of the Milan strain (MHS) nor in spontaneously hypertensive rats (SHR). Treatment also prevented the age-related hypoalbuminemia and hyperlipidemia observed in control MNS and significantly (P less than 0.01) reduced glomerular histologic damage, as demonstrated by light microscopy studies and measurement of sclerotic area. We conclude that: 1) MNS rats provide an animal model of long-lasting proteinuria characterized by an age-related increase in glomerular TXB2 production paralleled by progressive loss of renal structural integrity and function and by a secondary dyslipidemia; 2) pharmacological inhibition of glomerular TX-synthase attenuates the structural as well as the functional expression of kidney disease, without a primary effect on systemic blood pressure. These data are suggestive of an important modulating role of TXA2 in the progression of MNS renal disease.

  3. Perfil das doenças glomerulares em um hospital público do Distrito Federal Profile of glomerular diseases in a public hospital of Federal District, Brazil

    Directory of Open Access Journals (Sweden)

    Fabio Humberto Ribeiro Paes Ferraz

    2010-09-01

    Full Text Available INTRODUÇÃO: As doenças glomerulares são uma causa frequente de doença renal crônica, sobretudo nos países em desenvolvimento. OBJETIVO: O objetivo deste estudo foi determinar o perfil destas glomerulopatias em um hospital público da cidade de Brasília, Distrito Federal. MÉTODOS: Foram realizadas 121 biopsias renais pela equipe de nefrologia do Hospital Regional da Asa Norte (HRAN entre agosto de 2005 e maio de 2009. Foram excluídas oito biopsias realizadas em pacientes transplantados renais e analisados os prontuários dos 113 pacientes restantes. Dados analisados: sexo, idade, exames laboratoriais, síndrome glomerular, diagnóstico clínico, grau de fibrose intersticial, uso de imunossupressores, necessidade de diálise e desfecho clínico. RESULTADOS: A média de idade foi 34,9 ± 16,2 anos, com predomínio masculino (51,3%. As principais síndromes glomerulares foram: síndrome nefrótica (41,6% e glomerulonefrite rapidamente progressiva (35,4%. Entre as glomerulopatias primárias, houve predomínio da glomeruloesclerose segmentar e focal (26,9% e da nefropatia por IgA (25% e entre as secundárias a nefrite lúpica (50% e a glomerulonefrite proliferativa exsudativa difusa (34,2%. A maioria dos pacientes fez uso de imunossupressores (68,1% e quase um terço deles (29,2% necessitou de diálise durante a internação. Evoluíram para terapia dialítica crônica 13,3% dos pacientes e 10,6% evoluíram a óbito. CONCLUSÃO: Este estudo poderá contribuir para melhor entendimento epidemiológico das doenças glomerulares no Distrito Federal, orientando na adoção de políticas públicas visando permitir rápido diagnóstico e manejo clínico das mesmas.INTRODUCTION: Glomerular diseases are a frequent etiology of chronic kidney disease, especially in the developing countries. OBJECTIVE: To determine the profile of such glomerulopathies in a public hospital located in the city of Brasilia, Federal District. METHODS: 121 renal biopsies in

  4. Role of Protein Kinase C (PKC in Podocytes and Development of Glomerular Damage in Diabetic Nephropathy

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    Beina eTeng

    2014-11-01

    Full Text Available The early glomerular changes in diabetes include a podocyte phenotype with loss of slit diaphragm proteins, changes in the actin cytoskeleton and foot process architecture. This review focusses on the role of the Protein Kinase C family in podocytes and points out the differential roles of classical, novel and atypical PKCs in podocytes. Some PKC-isoforms are indispensable for proper glomerular development and slit diaphragm maintenance whereas others might be harmful when activated in the diabetic milieu. Therefore some might be interesting treatment targets in the early phase of diabetes.

  5. Relationship between islet α-cell function and glomerular filtration rate in type 2 diabetic patients

    Institute of Scientific and Technical Information of China (English)

    王晓宇

    2013-01-01

    Objective To analyze the isletα-cell function in type 2 diabetic patients with different levels of glomerular filtration rate (eGFR) .Methods Three hundred and eighty-eight cases of type 2 diabetic patients were classified into four groups according to eGFR:glomerular hyperfiltration group,normal renal function group,mild renal dysfunction group and moderate-severe renal dysfunction group.Oral glucose tolerance test,insulin releasing test and glucagon releasing test were conducted to compare

  6. Correlation between glomerular filtration rate and urinary N acetyl-beta-D glucosaminidase in children with persistent proteinuria in chronic glomerular disease

    Directory of Open Access Journals (Sweden)

    Jeong Deok Hong

    2012-04-01

    Full Text Available Purpose: Urinary excretion of N acetyl-beta-D glucosaminidase (NAG and ?#11437;microglobulin (?#11437;M was increased in the presence of proximal tubular damage. Based on these urinary materials, we investigated the ability of expecting renal function in chronic glomerular diseases. In this study, we evaluated the relationship between glomerular filtration rate (GFR urinary NAG, and urinary ?#11437;M. Methods: We evaluated 52 children with chronic kidney disease at the Chung-Ang University Hospital between January 2003 and August 2009. We investigated the 24-hour urinalysis and hematologic values in all 52 patients. Serum creatinine, creatinine clearance (Ccr, serum cystatin C, urinary ?#11437;M and urinary NAG were measured. Results: Out of 52 patients, there were 13 children with minimal change in disease, 3 children with focal segmental glomerulosclerosis, 17 children with immunoglobulin A nephropathy, 15 children with Henoch-Schonlein purpua nephritis, 3 children with poststreptococcal glomerulonephritis, and 1 child with thin glomerular basement membrane disease. In these patients, there were significant correlation between the Ccr and urinary NAG (r=-0.817; P&lt;0.01, and between the GFR (as determined by Schwartz method and urinary NAG (r=- 0.821; P&lt;0.01. In addition, there was a significant correlation between the GFR (as determined by Bokencamp method and urinary NAG (r=- 0.858; P&lt;0.01. Conclusion: In our study, there was a significant correlation between the GFR and urinary NAG, but there was no correlation between the GFR and urinary ?#11437;M, suggesting that the GFR can be predicted by urinary NAG in patients with chronic glomerular disease.

  7. Interactions between Autophagy and Bacterial Toxins: Targets for Therapy?

    Directory of Open Access Journals (Sweden)

    Jacques Mathieu

    2015-08-01

    Full Text Available Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.

  8. A role for TOR complex 2 signaling in promoting autophagy.

    Science.gov (United States)

    Vlahakis, Ariadne; Powers, Ted

    2014-01-01

    The conserved target of rapamycin (TOR) kinase is a central regulator of cell growth in response to nutrient availability. TOR forms 2 structurally and functionally distinct complexes, TORC1 and TORC2, and negatively regulates autophagy via TORC1. Here we demonstrate TOR also operates independently through the TORC2 signaling pathway to promote autophagy upon amino acid limitation. Under these conditions, TORC2, through its downstream target kinase Ypk1, inhibits the Ca(2+)- and Cmd1/calmodulin-dependent phosphatase, calcineurin, to enable the activation of the amino acid-sensing EIF2S1/eIF2α kinase, Gcn2, and promote autophagy. Thus TORC2 signaling regulates autophagy in a pathway distinct from TORC1 to provide a tunable response to the cellular metabolic state.

  9. The emerging role of acid sphingomyelinase in autophagy.

    Science.gov (United States)

    Perrotta, Cristiana; Cervia, Davide; De Palma, Clara; Assi, Emma; Pellegrino, Paolo; Bassi, Maria Teresa; Clementi, Emilio

    2015-05-01

    Autophagy, the main intracellular process of cytoplasmic material degradation, is involved in cell survival and death. Autophagy is regulated at various levels and novel modulators of its function are being continuously identified. An intriguing recent observation is that among these modulators is the sphingolipid metabolising enzyme, Acid Sphingomyelinase (A-SMase), already known to play a fundamental role in apoptotic cell death participating in several pathophysiological conditions. In this review we analyse and discuss the relationship between autophagy and A-SMase describing how A-SMase may regulate it and defining, for the first time, the existence of an A-SMase-autophagy axis. The imbalance of this axis plays a role in cancer, nervous system, cardiovascular, and hepatic disorders.

  10. Autophagy-modulating aminosteroids isolated from the sponge Cliona celata

    NARCIS (Netherlands)

    R.A. Keyzers; J. Daoust; M.T. Davies-Coleman; R. van Soest; A. Balgi; E. Donohue; M. Roberge; R.J. Andersen

    2008-01-01

    Clionamines A−D (1−4), new aminosteroids that modulate autophagy, have been isolated from South African specimens of the sponge Cliona celata. Clionamine D (4) has an unprecedented spiro bislactone side chain.

  11. Monitoring of autophagy is complicated--salinomycin as an example.

    Science.gov (United States)

    Jangamreddy, Jaganmohan Reddy; Panigrahi, Soumya; Łos, Marek J

    2015-03-01

    Monitoring of autophagy is challenging because of its multiple steps and lack of single befitting technique for a complete mechanistic understanding, which makes the task complicated. Here, we evaluate the functionality of autophagy triggered by salinomycin (anti-cancer stem cell agent) using flow cytometry and advanced microscopy. We show that salinomycin does induce functional autophagy at lower concentrations and such a dose is cell type-dependent. For example, PC3 cells show active autophagic flux at 10 μM concentration of salinomycin while murine embryonic fibroblasts already show an inhibition of flux at such doses. A higher concentration of salinomycin (i.e. 30 μM) inhibits autophagic flux in both cell types. The data confirms our previous findings that salinomycin is an inducer of autophagy, whereas autophagic flux inhibition is a secondary response.

  12. Role of autophagy in liver physiology and pathophysiology

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Autophagy is a highly conserved intracellular degradation pathway by which bulk cytoplasm and superfluous or damaged organelles are enveloped by double membrane structures termed autophagosomes. The autophago-somes then fuse with lysosomes for degradation of their contents, and the resulting amino acids can then recycle back to the cytosol. Autophagy is normally activated in response to nutrient deprivation and other stressors and occurs in all eukaryotes. In addition to maintaining energy and nutrient balance in the liver, it is now clear that autophagy plays a role in liver protein aggregates related diseases, hepatocyte cell death, steatohepatitis, hepatitis virus infection and hepatocellular carcinoma. In this review, I discuss the recent findings of autophagy with a focus on its role in liver pathophysiology.

  13. Heat shock response and autophagy--cooperation and control.

    Science.gov (United States)

    Dokladny, Karol; Myers, Orrin B; Moseley, Pope L

    2015-01-01

    Protein quality control (proteostasis) depends on constant protein degradation and resynthesis, and is essential for proper homeostasis in systems from single cells to whole organisms. Cells possess several mechanisms and processes to maintain proteostasis. At one end of the spectrum, the heat shock proteins modulate protein folding and repair. At the other end, the proteasome and autophagy as well as other lysosome-dependent systems, function in the degradation of dysfunctional proteins. In this review, we examine how these systems interact to maintain proteostasis. Both the direct cellular data on heat shock control over autophagy and the time course of exercise-associated changes in humans support the model that heat shock response and autophagy are tightly linked. Studying the links between exercise stress and molecular control of proteostasis provides evidence that the heat shock response and autophagy coordinate and undergo sequential activation and downregulation, and that this is essential for proper proteostasis in eukaryotic systems.

  14. Ultrastructure of autophagy in plant cells: a review.

    Science.gov (United States)

    van Doorn, Wouter G; Papini, Alessio

    2013-12-01

    Just as with yeasts and animal cells, plant cells show several types of autophagy. Microautophagy is the uptake of cellular constituents by the vacuolar membrane. Although microautophagy seems frequent in plants it is not yet fully proven to occur. Macroautophagy occurs farther away from the vacuole. In plants it is performed by autolysosomes, which are considerably different from the autophagosomes found in yeasts and animal cells, as in plants these organelles contain hydrolases from the onset of their formation. Another type of autophagy in plant cells (called mega-autophagy or mega-autolysis) is the massive degradation of the cell at the end of one type of programmed cell death (PCD). Furthermore, evidence has been found for autophagy during degradation of specific proteins, and during the internal degeneration of chloroplasts. This paper gives a brief overview of the present knowledge on the ultrastructure of autophagic processes in plants.

  15. Interactions between Autophagy and Bacterial Toxins: Targets for Therapy?

    Science.gov (United States)

    Mathieu, Jacques

    2015-08-04

    Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.

  16. Basal autophagy is required for the efficient catabolism of sialyloligosaccharides.

    Science.gov (United States)

    Seino, Junichi; Wang, Li; Harada, Yoichiro; Huang, Chengcheng; Ishii, Kumiko; Mizushima, Noboru; Suzuki, Tadashi

    2013-09-13

    Macroautophagy is an essential, homeostatic process involving degradation of a cell's own components; it plays a role in catabolizing cellular components, such as protein or lipids, and damaged or excess organelles. Here, we show that in Atg5(-/-) cells, sialyloligosaccharides specifically accumulated in the cytosol. Accumulation of these glycans was observed under non-starved conditions, suggesting that non-induced, basal autophagy is essential for their catabolism. Interestingly, once accumulated in the cytosol, sialylglycans cannot be efficiently catabolized by resumption of the autophagic process, suggesting that functional autophagy is important for preventing sialyloligosaccharides from accumulating in the cytosol. Moreover, knockdown of sialin, a lysosomal transporter of sialic acids, resulted in a significant reduction of sialyloligosaccharides, implying that autophagy affects the substrate specificity of this transporter. This study thus provides a surprising link between basal autophagy and catabolism of N-linked glycans.

  17. Detection of Autophagy in Caenorhabditis elegans Using GFP::LGG-1 as an Autophagy Marker.

    Science.gov (United States)

    Palmisano, Nicholas J; Meléndez, Alicia

    2016-01-04

    In yeast and mammalian cells, the autophagy protein Atg8/LC3 (microtubule-associated proteins 1A/1B light chain 3B encoded by MAP1LC3B) has been the marker of choice to detect double-membraned autophagosomes that are produced during the process of autophagy. A lipid-conjugated form of Atg8/LC3B is localized to the inner and outer membrane of the early-forming structure known as the phagophore. During maturation of autophagosomes, Atg8/LC3 bound to the inner autophagosome membrane remains in situ as the autophagosomes fuse with lysosomes. The nematode Caenorhabditis elegans is thought to conduct a similar process, meaning that tagging the nematode ortholog of Atg8/LC3-known as LGG-1-with a fluorophore has become a widely accepted method to visualize autophagosomes. Under normal growth conditions, GFP-modified LGG-1 displays a diffuse expression pattern throughout a variety of tissues, whereas, when under conditions that induce autophagy, the GFP::LGG-1 tag labels positive punctate structures, and its overall level of expression increases. Here, we present a protocol for using fluorescent reporters of LGG-1 coupled to GFP to monitor autophagosomes in vivo. We also discuss the use of alternative fluorescent markers and the possible utility of the LGG-1 paralog LGG-2.

  18. Glucocorticoids induce autophagy in rat bone marrow mesenchymal stem cells

    DEFF Research Database (Denmark)

    Wang, L.; Fan, J.; Lin, Y. S.;

    2015-01-01

    and their responses to diverse stimuli, however, the role of autophagy in glucocorticoidinduced damage to bone marrow mesenchymal stem cells (BMSCs) remains unclear. The current study confirmed that glucocorticoid administration impaired the proliferation of BMSCs. Transmission electron microscopy......Glucocorticoidinduced osteoporosis (GIOP) is a widespread clinical complication following glucocorticoid therapy. This irreversible damage to boneforming and resorbing cells is essential in the pathogenesis of osteoporosis. Autophagy is a physiological process involved in the regulation of cells...

  19. Autophagy Deficiency Promotes β-Lactam Production in Penicillium chrysogenum

    OpenAIRE

    Bartoszewska, Magdalena; Kiel, Jan A.K.W.; Bovenberg, Roel A. L.; Veenhuis, Marten; van der Klei, Ida J.

    2011-01-01

    We have investigated the significance of autophagy in the production of the β-lactam antibiotic penicillin (PEN) by the filamentous fungus Penicillium chrysogenum. In this fungus PEN production is compartmentalized in the cytosol and in peroxisomes. We demonstrate that under PEN-producing conditions significant amounts of cytosolic and peroxisomal proteins are degraded via autophagy. Morphological analysis, based on electron and fluorescence microscopy, revealed that this phenomenon might con...

  20. ROLE OF AUTOPHAGY IN AGE-RELATED MUSCLE LOSS

    OpenAIRE

    Lo Verso, Francesca

    2014-01-01

    Autophagy is an ubiquitous degradation system, that is conserved through species. Cells activate autophagy to degrade long-lived proteins, damaged organelles or portions of cytoplasm, that are engulfed in double-membrane vesicles called autophagosomes, that ultimately fuse to lysosomes, where the cargo is degraded and breakdown products are recycled to sustain cellular energetic demands. Skeletal muscle is the most abundant tissue in mammals and controls 80% of the blood glucose. We have r...

  1. Are mitochondrial reactive oxygen species required for autophagy?

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jianfei, E-mail: jjf73@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Maeda, Akihiro; Ji, Jing [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Baty, Catherine J.; Watkins, Simon C. [Center for Biologic Imaging, Department of Cell Biology and Physiology, University of Pittsburgh (United States); Greenberger, Joel S. [Department of Radiation Oncology, University of Pittsburgh (United States); Kagan, Valerian E., E-mail: kagan@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States)

    2011-08-19

    Highlights: {yields} Autophageal and apoptotic pathways were dissected in cytochrome c deficient cells. {yields} Staurosporine (STS)-induced autophagy was not accompanied by ROS generation. {yields} Autophagy was detectable in mitochondrial DNA deficient {rho}{sup 0} cells. {yields} Mitochondrial ROS are not required for the STS-induced autophagy in HeLa cells. -- Abstract: Reactive oxygen species (ROS) are said to participate in the autophagy signaling. Supporting evidence is obscured by interference of autophagy and apoptosis, whereby the latter heavily relies on ROS signaling. To dissect autophagy from apoptosis we knocked down expression of cytochrome c, the key component of mitochondria-dependent apoptosis, in HeLa cells using shRNA. In cytochrome c deficient HeLa1.2 cells, electron transport was compromised due to the lack of electron shuttle between mitochondrial respiratory complexes III and IV. A rapid and robust LC3-I/II conversion and mitochondria degradation were observed in HeLa1.2 cells treated with staurosporine (STS). Neither generation of superoxide nor accumulation of H{sub 2}O{sub 2} was detected in STS-treated HeLa1.2 cells. A membrane permeable antioxidant, PEG-SOD, plus catalase exerted no effect on STS-induced LC3-I/II conversion and mitochondria degradation. Further, STS caused autophagy in mitochondria DNA-deficient {rho}{sup o} HeLa1.2 cells in which both electron transport and ROS generation were completely disrupted. Counter to the widespread view, we conclude that mitochondrial ROS are not required for the induction of autophagy.

  2. Anti-DNA autoantibodies initiate experimental lupus nephritis by binding directly to the glomerular basement membrane in mice.

    Science.gov (United States)

    Krishnan, Meera R; Wang, Congmiao; Marion, Tony N

    2012-07-01

    The strongest serological correlate for lupus nephritis is antibody to double-stranded DNA, although the mechanism by which anti-DNA antibodies initiate lupus nephritis is unresolved. Most recent reports indicate that anti-DNA must bind chromatin in the glomerular basement membrane or mesangial matrix to form glomerular deposits. Here we determined whether direct binding of anti-DNA antibody to glomerular basement membrane is critical to initiate glomerular binding of anti-DNA in experimental lupus nephritis. Mice were co-injected with IgG monoclonal antibodies or hybridomas with similar specificity for DNA and chromatin but different IgG subclass and different relative affinity for basement membrane. Only anti-DNA antibodies that bound basement membrane bound to glomeruli, activated complement, and induced proteinuria whether injected alone or co-injected with a non-basement-membrane-binding anti-DNA antibody. Basement membrane-binding anti-DNA antibodies co-localized with heparan sulfate proteoglycan in glomerular basement membrane and mesangial matrix but not with chromatin. Thus, direct binding of anti-DNA antibody to antigens in the glomerular basement membrane or mesangial matrix may be critical to initiate glomerular inflammation. This may accelerate and exacerbate glomerular immune complex formation in human and murine lupus nephritis.

  3. Autophagy as a Possible Underlying Mechanism of Nanomaterial Toxicity

    Directory of Open Access Journals (Sweden)

    Vanessa Cohignac

    2014-07-01

    Full Text Available The rapid development of nanotechnologies is raising safety concerns because of the potential effects of engineered nanomaterials on human health, particularly at the respiratory level. Since the last decades, many in vivo studies have been interested in the pulmonary effects of different classes of nanomaterials. It has been shown that some of them can induce toxic effects, essentially depending on their physico-chemical characteristics, but other studies did not identify such effects. Inflammation and oxidative stress are currently the two main mechanisms described to explain the observed toxicity. However, the exact underlying mechanism(s still remain(s unknown and autophagy could represent an interesting candidate. Autophagy is a physiological process in which cytoplasmic components are digested via a lysosomal pathway. It has been shown that autophagy is involved in the pathogenesis and the progression of human diseases, and is able to modulate the oxidative stress and pro-inflammatory responses. A growing amount of literature suggests that a link between nanomaterial toxicity and autophagy impairment could exist. In this review, we will first summarize what is known about the respiratory effects of nanomaterials and we will then discuss the possible involvement of autophagy in this toxicity. This review should help understand why autophagy impairment could be taken as a promising candidate to fully understand nanomaterials toxicity.

  4. Targeting Protective Autophagy Exacerbates UV-Triggered Apoptotic Cell Death

    Directory of Open Access Journals (Sweden)

    Shih-Hwa Chiou

    2012-01-01

    Full Text Available Autophagy is activated by various stresses, including DNA damage, and previous studies of DNA damage-induced autophagy have focused on the response to chemotherapeutic drugs, ionizing radiation, and reactive oxygen species. In this study, we investigated the biological significance of autophagic response to ultraviolet (UV irradiation in A549 and H1299 cells. Our results indicated that UV induces on-rate autophagic flux in these cells. Autophagy inhibition resulting from the knockdown of beclin-1 and Atg5 reduced cell viability and enhanced apoptosis. Moreover, we found that ATR phosphorylation was accompanied by microtubule-associated protein 1 light chain 3B II (LC3B-II expression during the early phases following UV irradiation, which is a well-established inducer of ATR. Knocking down ATR further attenuated the reduction in LC3B-II at early stages in response to UV treatment. Despite the potential role of ATR in autophagic response, reduced ATR expression does not affect autophagy induction during late phases (24 and 48 h after UV treatment. The result is consistent with the reduced ATR phosphorylation at the same time points and suggests that autophagic response at this stage is activated via a distinct pathway. In conclusion, this study demonstrated that autophagy acts as a cytoprotective mechanism against UV-induced apoptosis and that autophagy induction accompanied with apoptosis at late stages is independent of ATR activation.

  5. Retinoid receptor signaling and autophagy in acute promyelocytic leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Orfali, Nina [Cork Cancer Research Center, University College Cork, Cork (Ireland); Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States); McKenna, Sharon L. [Cork Cancer Research Center, University College Cork, Cork (Ireland); Cahill, Mary R. [Department of Hematology, Cork University Hospital, Cork (Ireland); Gudas, Lorraine J., E-mail: ljgudas@med.cornell.edu [Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States); Mongan, Nigel P., E-mail: nigel.mongan@nottingham.ac.uk [Faculty of Medicine and Health Science, School of Veterinary Medicine and Science, University of Nottingham, LE12 5RD (United Kingdom); Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States)

    2014-05-15

    Retinoids are a family of signaling molecules derived from vitamin A with well established roles in cellular differentiation. Physiologically active retinoids mediate transcriptional effects on cells through interactions with retinoic acid (RARs) and retinoid-X (RXR) receptors. Chromosomal translocations involving the RARα gene, which lead to impaired retinoid signaling, are implicated in acute promyelocytic leukemia (APL). All-trans-retinoic acid (ATRA), alone and in combination with arsenic trioxide (ATO), restores differentiation in APL cells and promotes degradation of the abnormal oncogenic fusion protein through several proteolytic mechanisms. RARα fusion-protein elimination is emerging as critical to obtaining sustained remission and long-term cure in APL. Autophagy is a degradative cellular pathway involved in protein turnover. Both ATRA and ATO also induce autophagy in APL cells. Enhancing autophagy may therefore be of therapeutic benefit in resistant APL and could broaden the application of differentiation therapy to other cancers. Here we discuss retinoid signaling in hematopoiesis, leukemogenesis, and APL treatment. We highlight autophagy as a potential important regulator in anti-leukemic strategies. - Highlights: • Normal and aberrant retinoid signaling in hematopoiesis and leukemia is reviewed. • We suggest a novel role for RARα in the development of X-RARα gene fusions in APL. • ATRA therapy in APL activates transcription and promotes onco-protein degradation. • Autophagy may be involved in both onco-protein degradation and differentiation. • Pharmacologic autophagy induction may potentiate ATRA's therapeutic effects.

  6. Autophagy inhibitors as a potential antiamoebic treatment for Acanthamoeba keratitis.

    Science.gov (United States)

    Moon, Eun-Kyung; Kim, So-Hee; Hong, Yeonchul; Chung, Dong-Il; Goo, Youn-Kyoung; Kong, Hyun-Hee

    2015-07-01

    Acanthamoeba cysts are resistant to extreme physical and chemical conditions. Autophagy is an essential pathway for encystation of Acanthamoeba cells. To evaluate the possibility of an autophagic Acanthamoeba encystation mechanism, we evaluated autophagy inhibitors, such as 3-methyladenine (3MA), LY294002, wortmannin, bafilomycin A, and chloroquine. Among these autophagy inhibitors, the use of 3MA and chloroquine showed a significant reduction in the encystation ratio in Acanthamoeba cells. Wortmannin also inhibited the formation of mature cysts, while LY294002 and bafilomycin A did not affect the encystation of Acanthamoeba cells. Transmission electron microscopy revealed that 3MA and wortmannin inhibited autophagy formation and that chloroquine interfered with the formation of autolysosomes. Inhibition of autophagy or autolysosome formation resulted in a significant block in the encystation in Acanthamoeba cells. Clinical treatment with 0.02% polyhexamethylene biguanide (PHMB) showed high cytopathic effects on Acanthamoeba trophozoites and cysts; however, it also revealed high cytopathic effects on human corneal epithelial cells. In this study, we investigated effects of the combination of a low (0.00125%) concentration of PHMB with each of the autophagy inhibitors 3MA, wortmannin, and chloroquine on Acanthamoeba and human corneal epithelial cells. These new combination treatments showed low cytopathic effects on human corneal cells and high cytopathic effects on Acanthamoeba cells. Taken together, these results provide fundamental information for optimizing the treatment of Acanthamoeba keratitis.

  7. The role of autophagy in microbial infection and immunity

    Directory of Open Access Journals (Sweden)

    Desai M

    2015-01-01

    Full Text Available Mayura Desai,1 Rong Fang,2 Jiaren Sun11Department of Microbiology and Immunology, 2Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX, USAAbstract: The autophagy pathway represents an evolutionarily conserved cell recycling process that is activated in response to nutrient deprivation and other stress signals. Over the years, it has been linked to an array of cellular functions. Equally, a wide range of cell-intrinsic, as well as extracellular, factors have been implicated in the induction of the autophagy pathway. Microbial infections represent one such factor that can not only activate autophagy through specific mechanisms but also manipulate the response to the invading microbe's advantage. Moreover, in many cases, particularly among viruses, the pathway has been shown to be intricately involved in the replication cycle of the pathogen. Conversely, autophagy also plays a role in combating the infection process, both through direct destruction of the pathogen and as one of the key mediating factors in the host defense mechanisms of innate and adaptive immunity. Further, the pathway also plays a role in controlling the pathogenesis of infectious diseases by regulating inflammation. In this review, we discuss various interactions between pathogens and the cellular autophagic response and summarize the immunological functions of the autophagy pathway.Keywords: autophagy, xenophagy, antiviral, antibacterial

  8. Crosstalk between apoptosis and autophagy within the Beclin 1 interactome.

    Science.gov (United States)

    Maiuri, Maria Chiara; Criollo, Alfredo; Kroemer, Guido

    2010-02-03

    Although the essential genes for autophagy (Atg) have been identified, the molecular mechanisms through which Atg proteins control 'self eating' in mammalian cells remain elusive. Beclin 1 (Bec1), the mammalian orthologue of yeast Atg6, is part of the class III phosphatidylinositol 3-kinase (PI3K) complex that induces autophagy. The first among an increasing number of Bec1-interacting proteins that has been identified is the anti-apoptotic protein Bcl-2. The dissociation of Bec1 from Bcl-2 is essential for its autophagic activity, and Bcl-2 only inhibits autophagy when it is present in the endoplasmic reticulum (ER). A paper in this issue of the EMBO Journal has identified a novel protein, NAF-1 (nutrient-deprivation autophagy factor-1), that binds Bcl-2 at the ER. NAF-1 is a component of the inositol-1,4,5 trisphosphate (IP3) receptor complex, which contributes to the interaction of Bcl-2 with Bec1 and is required for Bcl-2 to functionally antagonize Bec1-mediated autophagy. This work provides mechanistic insights into how autophagy- and apoptosis-regulatory molecules crosstalk at the ER.

  9. Role of autophagy in prion protein-induced neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    Hao Yao; Deming Zhao; Sher Hayat Khan; Lifeng Yang

    2013-01-01

    Prion diseases,characterized by spongiform degeneration and the accumulation of misfolded and aggregated PrPSc in the central nervous system,are one of fatal neurodegenerative and infectious disorders of humans and animals.In earlier studies,autophagy vacuoles in neurons were frequently observed in neurodegenerative diseases such as Alzheimer's,Parkinson's,and Huntington's diseases as well as prion diseases.Autophagy is a highly conserved homeostatic process by which several cytoplasmic components (proteins or organelles) are sequestered in a doublemembrane-bound vesicle termed 'autophagosome' and degraded upon their fusion with lysosome.The pathway of intercellular self-digestion at basal physiological levels is indispensable for maintaining the healthy status of tissues and organs.In case of prion infection,increasing evidence indicates that autophagy has a crucial ability of eliminating pathological PrPSc accumulated within neurons.In contrast,autophagy dysfunction in affected neurons may contribute to the formation of spongiform changes.In this review,we summarized recent findings about the effect of mammalian autophagy in neurodegenerative disorders,particularly in prion diseases.We also summarized the therapeutic potential of some small molecules (such as lithium,rapamycin,Sirtuin 1 and resveratrol) targets to mitigate such diseases on brain function.Furthermore,we discussed the controversial role of autophagy,whether it mediates neuronal toxicity or serves a protective function in neurodegenerative disorders.

  10. Impaired Podocyte Autophagy Exacerbates Proteinuria in Diabetic Nephropathy.

    Science.gov (United States)

    Tagawa, Atsuko; Yasuda, Mako; Kume, Shinji; Yamahara, Kosuke; Nakazawa, Jun; Chin-Kanasaki, Masami; Araki, Hisazumi; Araki, Shin-Ichi; Koya, Daisuke; Asanuma, Katsuhiko; Kim, Eun-Hee; Haneda, Masakazu; Kajiwara, Nobuyuki; Hayashi, Kazuyuki; Ohashi, Hiroshi; Ugi, Satoshi; Maegawa, Hiroshi; Uzu, Takashi

    2016-03-01

    Overcoming refractory massive proteinuria remains a clinical and research issue in diabetic nephropathy. This study was designed to investigate the pathogenesis of massive proteinuria in diabetic nephropathy, with a special focus on podocyte autophagy, a system of intracellular degradation that maintains cell and organelle homeostasis, using human tissue samples and animal models. Insufficient podocyte autophagy was observed histologically in patients and rats with diabetes and massive proteinuria accompanied by podocyte loss, but not in those with no or minimal proteinuria. Podocyte-specific autophagy-deficient mice developed podocyte loss and massive proteinuria in a high-fat diet (HFD)-induced diabetic model for inducing minimal proteinuria. Interestingly, huge damaged lysosomes were found in the podocytes of diabetic rats with massive proteinuria and HFD-fed, podocyte-specific autophagy-deficient mice. Furthermore, stimulation of cultured podocytes with sera from patients and rats with diabetes and massive proteinuria impaired autophagy, resulting in lysosome dysfunction and apoptosis. These results suggest that autophagy plays a pivotal role in maintaining lysosome homeostasis in podocytes under diabetic conditions, and that its impairment is involved in the pathogenesis of podocyte loss, leading to massive proteinuria in diabetic nephropathy. These results may contribute to the development of a new therapeutic strategy for advanced diabetic nephropathy.

  11. Glomerular changes in trisomy 18-related horseshoe kidney: report of a case and review of the literature

    Directory of Open Access Journals (Sweden)

    Giuseppina Parodo

    2012-10-01

    Full Text Available A case of horseshoe kidney is reported in a 11 week-old fetus affected by trisomy 18. Macroscopic examination did not show any other pathological change. The histological picture of the fused-kidney was characterized by architectural and glomerular changes. At x 100 magnification, large areas of metanephric mesenchyme, characterized by spindle cells surrounded by a loose oedematous stroma, were detected in the deep cortex and in the medulla. At higher power, multiple glomerular changes were observed. Maldeveloped glomeruli showed enlarged capsular spaces, adhesions between vascular tuft and capsular cells, podocytes in multiple layers, and large glomerular bodies formed by two vascular tufts. Our data confirm previous reports on glomerular changes in horseshoe kidney, and reinforce the hypothesis that horseshoe kidney should not be considered a simple fusion problem, but a complex developmental abnormality, possibly involving glomerular development.

  12. Structural Alterations of the Glomerular Wall And Vessels in Early Stages of Diabetes Mellitus: Light and Transmission Electron Microscopic Study

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    Dkhil MA

    2007-01-01

    Full Text Available Objective: The capillary changes at the initial stage of diabetes may show an angioarchitecture clearly different from those of later stages and,/or very severe glomerular change. However, the onset of alterations in the early phases is unclear. This study attempts to determine the functional and structural alterations of the glomerular wall and vesicles in the early stage of diabetes.Material and Methods: Twenty-five adult rats were used in this study. They were divided into two groups: the first group of five was used as a control .The second group of 20 (the experimental group was injected intraperitoneally by a single dose of streptozotocin to induce hyperglycemia. Rats were sacrificed after ten days, two months, and four months.Five rats at two months of age with hyperglycemia were treated with insulin for eight weeks. Renal tissues were prepared by routine technique for light and transmission electron microscopic evaluation. Results: By light microscopy after ten days of induced hyperglycemia, there were no structural modifications detected either in renal glomerular fine vessels or in the glomerular basement membrane of the glomerular capillaries. After two months, there was a moderate glomerular enlargement and dilatation of glomerular capillaries, afferent, and efferent arterioles. After four months, glomerular basement membrane thickening was the only structural alteration observed. Recovery of the glomerular alterations was observed after two months of treatment with insulin. Conclusion: In early stages of diabetes mellitus in rats, there was an increase in the diameter of glomerular vessels. In later stages of the disease, the reverse was seen, but insulin treatment had a positive role in reversing these changes in the study subjects.

  13. Expression and significance of Pdlim2 in the glomerular podocyte of hyperlipidemic rate

    Institute of Scientific and Technical Information of China (English)

    彭兰

    2014-01-01

    Objective To investigate the expression changes and significance of Pdlim2 in the glomerular podocyte of hyperlipidemic rats.Methods Forty-five individuals of SD rats were divided randomly into 3 groups(n=15 in each group).The control group was fed with normal diet.The high fat group was fed with high fat diet.The simvastatin

  14. Impaired autoregulation of the glomerular filtration rate in patients with nondiabetic nephropathies

    DEFF Research Database (Denmark)

    Christensen, P K; Hommel, E E; Clausen, P

    1999-01-01

    BACKGROUND: The ability of the kidney to maintain constancy of the glomerular filtration rate (GFR) over a wide range of renal perfusion pressures is termed autoregulation. Defective autoregulation of GFR has been demonstrated in diabetic nephropathy. Whether this is also the case in patients...

  15. Antimyeloperoxidase antibodies rapidly induce alpha-4-integrin-dependent glomerular neutrophil adhesion.

    Science.gov (United States)

    Kuligowski, Michael P; Kwan, Rain Y Q; Lo, Cecilia; Wong, Cyndi; James, Will G; Bourges, Dorothee; Ooi, Joshua D; Abeynaike, Latasha D; Hall, Pam; Kitching, A Richard; Hickey, Michael J

    2009-06-18

    Patients with antineutrophil cytoplasmic antibodies (ANCAs) frequently develop severe vasculitis and glomerulonephritis. Although ANCAs, particularly antimyeloperoxidase (anti-MPO), have been shown to promote leukocyte adhesion in postcapillary venules, their ability to promote adhesion in the glomerular vasculature is less clear. We used intravital microscopy to examine glomerular leukocyte adhesion induced by anti-MPO. In mice pretreated with LPS, 50 microg anti-MPO induced LFA-1-dependent adhesion in glomeruli. In concert with this finding, in mice pretreated with LPS, more than 80% of circulating neutrophils bound anti-MPO within 5 minutes of intravenous administration. However, even in the absence of LPS, more than 40% of circulating neutrophils bound anti-MPO in vivo, a response not seen in MPO(-/-) mice. In addition, a higher dose of anti-MPO (200 microg) induced robust glomerular leukocyte adhesion in the absence of LPS. The latter response was beta2-integrin independent, instead requiring the alpha4-integrin, which was up-regulated on neutrophils in response to anti-MPO. These data indicate that anti-MPO antibodies bind to circulating neutrophils, and can induce glomerular leukocyte adhesion via multiple pathways. Lower doses induce adhesion only after an infection-related stimulus, whereas higher doses are capable of inducing responses in the absence of an additional inflammatory stimulus, via alternative adhesion mechanisms.

  16. QUANTIFICATION OF GLOMERULAR EPITHELIAL-CELL ADHESION BY USING ANTI-DNA ANTIBODIES IN ELISA

    NARCIS (Netherlands)

    COERS, W; SMEENK, RJT; SALANT, DJ; WEENING, JJ

    1992-01-01

    A sensitive and reproducible microassay is described for quantification of adhesion of cells to matrix-coated 96-wells plates under different experimental conditions. For this purpose glomerular visceral epithelial cells (GVEC) were used. Attached GVEC were fixed with methanol and incubated with a m

  17. Measurement of glomerular filtration rate in adults: accuracy of five single-sample plasma clearance methods

    DEFF Research Database (Denmark)

    Rehling, M; Rabøl, A

    1989-01-01

    After an intravenous injection of a tracer that is removed from the body solely by filtration in the kidneys, the glomerular filtration rate (GFR) can be determined from its plasma clearance. The method requires a great number of blood samples but collection of urine is not needed. In the present...

  18. Rapid decline in glomerular filtration rate during the first weeks following heart transplantation

    DEFF Research Database (Denmark)

    Hornum, M; Andersen, M; Gustafsson, F;

    2011-01-01

    We hypothesized that a decrease in renal function is seen immediately after heart transplantation (HTX) with little recovery over time. Twelve consecutive patients had their glomerular filtration rate (GFR) measured using (51)Cr-ethylenediaminetetraacetic acid (EDTA) measured GFR (mGFR) before...

  19. Reliability of estimated glomerular filtration rate in patients treated with platinum containing therapy

    DEFF Research Database (Denmark)

    Lauritsen, Jakob; Gundgaard, Maria G; Mortensen, Mette S

    2014-01-01

    Estimates of glomerular filtration rate (eGFR) are widely used when administering nephrotoxic chemotherapy. No studies performed in oncology patients have shown whether eGFR can safely substitute a measured GFR (mGFR) based on a marker method. We aimed to assess the validity of four major formula...

  20. The Spectrum of Glomerular Diseases on Renal Biopsy: Data From A Single Tertiary Center In Oman

    Directory of Open Access Journals (Sweden)

    Dawood Al Riyami

    2013-05-01

    Full Text Available Objective: To study the pattern of glomerular disease (GD from the result of renal biopsies at our center.Methods: We conducted a retrospective review of 190 adult native renal biopsy reports from the pathology registry of renal biopsy performed at our hospital between 1992 and 2010.Results: Lupus nephritis was the most common pathology 48/133 (36.1% with a female preponderance. The most common primary glomerular disease was focal segmental glomerulosclerosis (FSGS 26/133(19.5%, followed by membranous glemerulopathy (MGN 13/133 (9.8%, and mesangial proliferative glomerulonephritis 6/133 (4.5%. IgA nephropathy and acute proliferative glomerulonephritis each accounted for 4/133 (3.0%. Membranoproliferative glomerulonephritis accounted for 3/133 (2.3%. Focal proliferative and cresentic glomerulonephritis each accounted for 2/133 (1.5%. Vasculitis was not common and there was no report of anti-GBM disease.Conclusion: Among the secondary glomerular diseases, lupus nephritis was the commonest condition with a female preponderance. Among the primary glomerular diseases, FSGS was the commonest. These results are consistent with global trend. IgA nephropathy is not common as the case in the Caucasian population. Vasculitis was not common and there was no report of anti-GBM disease.

  1. REPRODUCTIVE CONDITION, GLOMERULAR ADENOSINE DIPHOSPHATASE ACTIVITY, AND PLATELET-AGGREGATION IN THE RAT - EFFECT OF ENDOTOXIN

    NARCIS (Netherlands)

    VISSCHER, CA; FAAS, MM; BAKKER, WW; SCHUILING, GA

    1993-01-01

    In experiment A, the activity of the glomerular antithrombotic enzyme adenosine diphosphatase (ADPase) and the sensitivity of this enzyme for endotoxin (1.0 mug/kg BW) in various reproductive conditions of female rats were studied through use of enzyme histochemical methods. In experiment B, the eff

  2. MRI-based glomerular morphology and pathology in whole human kidneys.

    Science.gov (United States)

    Beeman, Scott C; Cullen-McEwen, Luise A; Puelles, Victor G; Zhang, Min; Wu, Teresa; Baldelomar, Edwin J; Dowling, John; Charlton, Jennifer R; Forbes, Michael S; Ng, Amanda; Wu, Qi-zhu; Armitage, James A; Egan, Gary F; Bertram, John F; Bennett, Kevin M

    2014-06-01

    Nephron number (N(glom)) and size (V(glom)) are correlated with risk for chronic cardiovascular and kidney disease and may be predictive of renal allograft viability. Unfortunately, there are no techniques to assess N(glom) and V(glom) in intact kidneys. This work demonstrates the use of cationized ferritin (CF) as a magnetic resonance imaging (MRI) contrast agent to measure N(glom) and V(glom) in viable human kidneys donated to science. The kidneys were obtained from patients with varying levels of cardiovascular and renal disease. CF was intravenously injected into three viable human kidneys. A fourth control kidney was perfused with saline. After fixation, immunofluorescence and electron microscopy confirmed binding of CF to the glomerulus. The intact kidneys were imaged with three-dimensional MRI and CF-labeled glomeruli appeared as punctate spots. Custom software identified, counted, and measured the apparent volumes of CF-labeled glomeruli, with an ~6% false positive rate. These measurements were comparable to stereological estimates. The MRI-based technique yielded a novel whole kidney distribution of glomerular volumes. Histopathology demonstrated that the distribution of CF-labeled glomeruli may be predictive of glomerular and vascular disease. Variations in CF distribution were quantified using image texture analyses, which be a useful marker of glomerular sclerosis. This is the first report of direct measurement of glomerular number and volume in intact human kidneys.

  3. Minimal change-like glomerular alterations induced by a human plasma factor

    NARCIS (Netherlands)

    Cheung, PK; Klok, PA; Bakker, WW

    1996-01-01

    Circulating factors, including the plasma protease (100KF) described previously, have been suspected to play a role in the pathogenesis of minimal change disease (MCD) for several decades. This factor was able to induce MCD-like alterations in kidney tissue in vitro, i.e. impairment of glomerular po

  4. Tubulo-glomerular feedback response: enhancement in adult spontaneously hypertensive rats and effects of anaesthetics

    DEFF Research Database (Denmark)

    Leyssac, P P; Holstein-Rathlou, N H

    1989-01-01

    Open-loop tubulo-glomerular feedback (TGF) responses were measured in halothane anaesthetized spontaneously hypertensive rats (SHR), in normotensive Wistar Kyoto (WKY) and Sprague-Dawley rats (SPRD), and in inactin anaesthetized SPRD. Proximal intratubular free flow pressures (FFP) (13.8-14.7 mm Hg...

  5. Modulation of glomerular ECTO-ADPase expression by oestradiol - A histochemical study

    NARCIS (Netherlands)

    Faas, MM; Bakker, WW; Klok, PA; Baller, JFW; Schuiling, GA

    1997-01-01

    The effect of 17-beta-oestradiol (OE2) upon the activity of the glomerular anti-thrombotic ecto-enzyme ADPase was studied in cyclic and ovariectomized (OVX) Wistar rats. On day 0 (i.e. at the time of ovariectomy or 11 days after ovariectomy) rats received OE2-releasing Silastic implants or empty imp

  6. Reduced glomerular angiotensin II receptor density in diabetes mellitus in the rat: time course and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Wilkes, B.M.

    1987-04-01

    Glomerular angiotensin II receptors are reduced in number in early diabetes mellitus, which may contribute to hyperfiltration and glomerular injury. The time course and role of the renin-angiotensin-aldosterone system in the pathogenesis of the receptor abnormality were studied in male Sprague-Dawley rats made diabetic with streptozotocin (65 mg, iv). Glomerular angiotensin II receptors were measured by Scatchard analysis; insulin, renin activity, angiotensin II, and aldosterone were measured by RIA. Diabetes mellitus was documented at 24 h by a rise in plasma glucose (vehicle-injected control, 133 +/- 4; diabetic, 482 +/- 22 mg/dl and a fall in plasma insulin (control, 53.1 +/- 5.7; diabetic, 35.6 +/- 4.0 microIU/ml. At 24 h glomerular angiotensin II receptor density was decreased by 26.5% in diabetic rats (control, 75.5 +/- 9.6 X 10(6); diabetic, 55.5 +/- 8.3 X 10(6) receptors/glomerulus. Receptor occupancy could not explain the defect, because there was reduced binding in diabetic glomeruli after pretreatment with 3 M MgCl/sub 2/, a maneuver that caused dissociation of previously bound hormone. There was a progressive return of the receptor density toward normal over the 60 days following induction of diabetes, with diabetic glomeruli measuring 22.7%, 14.8%, and 3.7% fewer receptors than age-matched controls at 11 days, 1 month, and 2 months, respectively.

  7. A re-evaluation of the determinants of glomerular filtration rate

    DEFF Research Database (Denmark)

    Karlsen, F M; Holstein-Rathlou, N H; Leyssac, P P

    1995-01-01

    Several factors are potentially able to change the glomerular filtration rate (GFR) and thereby participate in its regulation, but only a few factors seem to be physiologically important. The variable nature of proximal tubular pressure should be recognized as important in the regulation of GFR...

  8. Limited value of cystatin-C over estimated glomerular filtration rate for heart failure risk stratification.

    Directory of Open Access Journals (Sweden)

    Elisabet Zamora

    Full Text Available BACKGROUND: To compare the prognostic value of estimated glomerular filtration rate, cystatin-C, an alternative renal biomarker, and their combination, in an outpatient population with heart failure. Estimated glomerular filtration rate is routinely used to assess renal function in heart failure patients. We recently demonstrated that the Cockroft-Gault formula is the best among the most commonly used estimated glomerular filtration rate formulas for predicting heart failure prognosis. METHODOLOGY/PRINCIPAL FINDINGS: A total of 879 consecutive patients (72% men, age 70.4 years [P(25-75 60.5-77.2] were studied. The etiology of heart failure was mainly ischemic heart disease (52.7%. The left ventricular ejection fraction was 34% (P(25-75 26-43%. Most patients were New York Heart Association class II (65.8% or III (25.9%. During a median follow-up of 3.46 years (P(25-75 1.85-5.05, 312 deaths were recorded. In an adjusted model, estimated glomerular filtration rate and cystatin-C showed similar prognostic value according to the area under the curve (0.763 and 0.765, respectively. In Cox regression, the multivariable analysis hazard ratios were 0.99 (95% CI: 0.98-1, P = 0.006 and 1.14 (95% CI: 1.02-1.28, P = 0.02 for estimated glomerular filtration rate and cystatin-C, respectively. Reclassification, assessed by the integration discrimination improvement and the net reclassification improvement indices, was poorer with cystatin-C (-0.5 [-1.0;-0.1], P = 0.024 and -4.9 [-8.8;-1.0], P = 0.013, respectively. The value of cystatin-C over estimated glomerular filtration rate for risk-stratification only emerged in patients with moderate renal dysfunction (eGFR 30-60 ml/min/1.73 m(2, chi-square 12.9, P<0.001. CONCLUSIONS/SIGNIFICANCE: Taken together, the results indicate that estimated glomerular filtration rate and cystatin-C have similar long-term predictive values in a real-life ambulatory heart failure population. Cystatin-C seems to

  9. The yeast Saccharomyces cerevisiae : an overview of methods to study autophagy progression

    NARCIS (Netherlands)

    Delorme-Axford, Elizabeth; Guimaraes, Rodrigo Soares; Reggiori, Fulvio; Klionsky, Daniel J

    2015-01-01

    Macroautophagy (hereafter autophagy) is a highly evolutionarily conserved process essential for sustaining cellular integrity, homeostasis, and survival. Most eukaryotic cells constitutively undergo autophagy at a low basal level. However, various stimuli, including starvation, organelle deteriorati

  10. Transient overexpression of Werner protein rescues starvation induced autophagy in Werner syndrome cells.

    Science.gov (United States)

    Maity, Jyotirindra; Bohr, Vilhelm A; Laskar, Aparna; Karmakar, Parimal

    2014-12-01

    Reduced autophagy may be associated with normal and pathological aging. Here we report a link between autophagy and Werner protein (WRNp), mutated in Werner syndrome, the human premature aging Werner syndrome (WS). WRN mutant fibroblast AG11395 and AG05229 respond weakly to starvation induced autophagy compared to normal cells. While the fusion of phagosomes with lysosome is normal, WS cells contain fewer autophagy vacuoles. Cellular starvation autophagy in WS cells is restored after transfection with full length WRN. Further, siRNA mediated silencing of WRN in the normal fibroblast cell line WI-38 results in decreased autophagy and altered expression of autophagy related proteins. Thus, our observations suggest that WRN may have a role in controlling autophagy and hereby cellular maintenance.

  11. A switch from canonical to noncanonical autophagy shapes B cell responses.

    Science.gov (United States)

    Martinez-Martin, Nuria; Maldonado, Paula; Gasparrini, Francesca; Frederico, Bruno; Aggarwal, Shweta; Gaya, Mauro; Tsui, Carlson; Burbage, Marianne; Keppler, Selina Jessica; Montaner, Beatriz; Jefferies, Harold B J; Nair, Usha; Zhao, Yan G; Domart, Marie-Charlotte; Collinson, Lucy; Bruckbauer, Andreas; Tooze, Sharon A; Batista, Facundo D

    2017-02-10

    Autophagy is important in a variety of cellular and pathophysiological situations; however, its role in immune responses remains elusive. Here, we show that among B cells, germinal center (GC) cells exhibited the highest rate of autophagy during viral infection. In contrast to mechanistic target of rapamycin complex 1-dependent canonical autophagy, GC B cell autophagy occurred predominantly through a noncanonical pathway. B cell stimulation was sufficient to down-regulate canonical autophagy transiently while triggering noncanonical autophagy. Genetic ablation of WD repeat domain, phosphoinositide-interacting protein 2 in B cells alone enhanced this noncanonical autophagy, resulting in changes of mitochondrial homeostasis and alterations in GC and antibody-secreting cells. Thus, B cell activation prompts a temporal switch from canonical to noncanonical autophagy that is important in controlling B cell differentiation and fate.

  12. Laminin α2-mediated focal adhesion kinase activation triggers Alport glomerular pathogenesis.

    Science.gov (United States)

    Delimont, Duane; Dufek, Brianna M; Meehan, Daniel T; Zallocchi, Marisa; Gratton, Michael Anne; Phillips, Grady; Cosgrove, Dominic

    2014-01-01

    It has been known for some time that laminins containing α1 and α2 chains, which are normally restricted to the mesangial matrix, accumulate in the glomerular basement membranes (GBM) of Alport mice, dogs, and humans. We show that laminins containing the α2 chain, but not those containing the α1 chain activates focal adhesion kinase (FAK) on glomerular podocytes in vitro and in vivo. CD151-null mice, which have weakened podocyte adhesion to the GBM rendering these mice more susceptible to biomechanical strain in the glomerulus, also show progressive accumulation of α2 laminins in the GBM, and podocyte FAK activation. Analysis of glomerular mRNA from both models demonstrates significant induction of MMP-9, MMP-10, MMP-12, MMPs linked to GBM destruction in Alport disease models, as well as the pro-inflammatory cytokine IL-6. SiRNA knockdown of FAK in cultured podocytes significantly reduced expression of MMP-9, MMP-10 and IL-6, but not MMP-12. Treatment of Alport mice with TAE226, a small molecule inhibitor of FAK activation, ameliorated fibrosis and glomerulosclerosis, significantly reduced proteinuria and blood urea nitrogen levels, and partially restored GBM ultrastructure. Glomerular expression of MMP-9, MMP-10 and MMP-12 mRNAs was significantly reduced in TAE226 treated animals. Collectively, this work identifies laminin α2-mediated FAK activation in podocytes as an important early event in Alport glomerular pathogenesis and suggests that FAK inhibitors, if safe formulations can be developed, might be employed as a novel therapeutic approach for treating Alport renal disease in its early stages.

  13. Laminin α2-mediated focal adhesion kinase activation triggers Alport glomerular pathogenesis.

    Directory of Open Access Journals (Sweden)

    Duane Delimont

    Full Text Available It has been known for some time that laminins containing α1 and α2 chains, which are normally restricted to the mesangial matrix, accumulate in the glomerular basement membranes (GBM of Alport mice, dogs, and humans. We show that laminins containing the α2 chain, but not those containing the α1 chain activates focal adhesion kinase (FAK on glomerular podocytes in vitro and in vivo. CD151-null mice, which have weakened podocyte adhesion to the GBM rendering these mice more susceptible to biomechanical strain in the glomerulus, also show progressive accumulation of α2 laminins in the GBM, and podocyte FAK activation. Analysis of glomerular mRNA from both models demonstrates significant induction of MMP-9, MMP-10, MMP-12, MMPs linked to GBM destruction in Alport disease models, as well as the pro-inflammatory cytokine IL-6. SiRNA knockdown of FAK in cultured podocytes significantly reduced expression of MMP-9, MMP-10 and IL-6, but not MMP-12. Treatment of Alport mice with TAE226, a small molecule inhibitor of FAK activation, ameliorated fibrosis and glomerulosclerosis, significantly reduced proteinuria and blood urea nitrogen levels, and partially restored GBM ultrastructure. Glomerular expression of MMP-9, MMP-10 and MMP-12 mRNAs was significantly reduced in TAE226 treated animals. Collectively, this work identifies laminin α2-mediated FAK activation in podocytes as an important early event in Alport glomerular pathogenesis and suggests that FAK inhibitors, if safe formulations can be developed, might be employed as a novel therapeutic approach for treating Alport renal disease in its early stages.

  14. Pattern of glomerular diseases in Sudanese children:A clinico-pathological study

    Directory of Open Access Journals (Sweden)

    Abdelraheem Mohamed

    2010-01-01

    Full Text Available Glomerular diseases are a common cause of chronic kidney disease (CKD in many countries. The pattern of glomerular diseases has been reported in adult Sudanese patients but there has been no previous study on Sudanese children. The aim of this study is to describe the pattern of glomerular diseases in Sudanese children from a clinico-pathological perspective. We retrospectively reviewed the clinical records of 321 children seen with nephritis/nephrosis at the Pediatric Nephrology Unit, Soba University Hospital and Dr. Salma Dialysis and Kidney Transplantation Centre, Khartoum, Sudan during the period from 2002 to 2007. Biopsies were studied with light microscopy and immuno-histochemistry with electron microscopy performed abroad in selected patients (predominantly Alport′s. The mean age of the 321 study children was 8.71 years (range 2 months-16 yrs of whom, 188 were males (60.2%. The most common presentation was with the nephrotic syndrome, seen in 202 patients (62.9%. The most common glomerular disease encountered was minimal change disease, seen in 96 children (29.9%, followed by post-infectious GN in 78 (24.3% and focal and segmental glome-rulosclerosis, seen in 44 patients (13.7%. Membranoproliferative GN (MPGN was seen in 43 patients (13.4% while mesangioproliferative GN was seen in 24 (7.5%. Systemic lupus erythematosus (SLE was the most common secondary glomerular disease accounting for 16 patients (4.9%. HBsAg was positive in 10 patients and the most common associated lesion was MPGN (60%. Histopathology enabled us to change the therapy in 55.3% of the patients. Our study suggests that the pattern of GN in our cohort of patients is comparable with reports from other parts of the world with a high prevalence of post-infectious GN. Renal biopsies have an important part in planning therapy and management. Also, the importance of establishing a Sudanese renal registry including pediatric patients is stressed.

  15. Glomerular C3d as a novel prognostic marker for renal vasculitis.

    Science.gov (United States)

    Villacorta, Javier; Diaz-Crespo, Francisco; Acevedo, Mercedes; Guerrero, Carmen; Campos-Martin, Yolanda; García-Díaz, Eugenio; Mollejo, Manuela; Fernandez-Juarez, Gema

    2016-10-01

    Pauci-immune necrotizing crescentic glomerulonephritis is the histologic substrate of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Several studies in animal models have demonstrated the crucial role of complement activation in the pathogenesis of ANCA-associated vasculitis, but only small series have analyzed the prognostic implications of complement glomerular deposits. This study aimed to assess the clinical and prognostic implications of C3d- and C4d-positive glomerular staining in renal vasculitis. Eighty-five patients with a diagnosis of pauci-immune necrotizing crescentic glomerulonephritis were included in the study. C3d and C4d were analyzed by immunohistochemical staining using a polyclonal antibody. The primary predictors were glomerular C3d- and C4d-positive staining. The primary end point was the cumulative percentage of patients who developed end-stage renal disease. Glomerular staining for C3d and C4d was observed in 42 (49.4%) of 85 biopsies and 38 (44.7%) of 85 biopsies, respectively. C3d-positive staining was associated with the severity of renal impairment and with a lower response rate to treatment (P=.003 and P=.04, respectively). Renal survival at 2 and 5 years was 60.9% and 51.8% in C3d-positive patients compared with 87.7% and 78.9% in C3d-negative patients (P=.04). C4d-positive staining did not show any impact in renal outcome. When adjusted by renal function and other histologic parameters, C3d staining remained as an independent predictor for renal survival (hazard ratio, 2.5; 95% confidence interval, 1.1-5.7; P=.03). Therefore, this study demonstrates that C3d-positive glomerular staining is an independent risk factor for the development of end-stage renal disease in ANCA-associated renal vasculitis.

  16. HANAC Syndrome Col4a1 Mutation Causes Neonate Glomerular Hyperpermeability and Adult Glomerulocystic Kidney Disease.

    Science.gov (United States)

    Chen, Zhiyong; Migeon, Tiffany; Verpont, Marie-Christine; Zaidan, Mohamad; Sado, Yoshikazu; Kerjaschki, Dontscho; Ronco, Pierre; Plaisier, Emmanuelle

    2016-04-01

    Hereditary angiopathy, nephropathy, aneurysms, and muscle cramps (HANAC) syndrome is an autosomal dominant syndrome caused by mutations in COL4A1 that encodes the α1 chain of collagen IV, a major component of basement membranes. Patients present with cerebral small vessel disease, retinal tortuosity, muscle cramps, and kidney disease consisting of multiple renal cysts, chronic kidney failure, and sometimes hematuria. Mutations producing HANAC syndrome localize within the integrin binding site containing CB3[IV] fragment of the COL4A1 protein. To investigate the pathophysiology of HANAC syndrome, we generated mice harboring the Col4a1 p.Gly498Val mutation identified in a family with the syndrome. Col4a1 G498V mutation resulted in delayed glomerulogenesis and podocyte differentiation without reduction of nephron number, causing albuminuria and hematuria in newborns. The glomerular defects resolved within the first month, but glomerular cysts developed in 3-month-old mutant mice. Abnormal structure of Bowman's capsule was associated with metalloproteinase induction and activation of the glomerular parietal epithelial cells that abnormally expressed CD44,α-SMA, ILK, and DDR1. Inflammatory infiltrates were observed around glomeruli and arterioles. Homozygous Col4a1 G498V mutant mice additionally showed dysmorphic papillae and urinary concentration defects. These results reveal a developmental role for the α1α1α2 collagen IV molecule in the embryonic glomerular basement membrane, affecting podocyte differentiation. The observed association between molecular alteration of the collagenous network in Bowman's capsule of the mature kidney and activation of parietal epithelial cells, matrix remodeling, and inflammation may account for glomerular cyst development and CKD in patients with COL4A1-related disorders.

  17. AGEs Induced Autophagy Impairs Cutaneous Wound Healing via Stimulating Macrophage Polarization to M1 in Diabetes

    OpenAIRE

    Yuanyuan Guo; Cai Lin; Peng Xu; Shan Wu; Xiujun Fu; Weidong Xia; Min Yao

    2016-01-01

    Autophagy is essential in physiological and pathological processes, however, the role of autophagy in cutaneous wound healing and the underlying molecular mechanism remain elusive. We hypothesized that autophagy plays an important role in regulating wound healing. Here, we show that enhanced autophagy negatively impacts on normal cutaneous healing process and is related to chronic wounds as demonstrated by the increased LC3 in diabetic mice skin or patients’ chronic wounds. In addition, inhib...

  18. Autophagy is required for exercise training-induced skeletal muscle adaptation and improvement of physical performance.

    Science.gov (United States)

    Lira, Vitor A; Okutsu, Mitsuharu; Zhang, Mei; Greene, Nicholas P; Laker, Rhianna C; Breen, David S; Hoehn, Kyle L; Yan, Zhen

    2013-10-01

    Pathological and physiological stimuli, including acute exercise, activate autophagy; however, it is unknown whether exercise training alters basal levels of autophagy and whether autophagy is required for skeletal muscle adaptation to training. We observed greater autophagy flux (i.e., a combination of increased LC3-II/LC3-I ratio and LC3-II levels and reduced p62 protein content indicating a higher rate of initiation and resolution of autophagic events), autophagy protein expression (i.e., Atg6/Beclin1, Atg7, and Atg8/LC3) and mitophagy protein Bnip3 expression in tonic, oxidative muscle compared to muscles of either mixed fiber types or of predominant glycolytic fibers in mice. Long-term voluntary running (4 wk) resulted in increased basal autophagy flux and expression of autophagy proteins and Bnip3 in parallel to mitochondrial biogenesis in plantaris muscle with mixed fiber types. Conversely, exercise training promoted autophagy protein expression with no significant increases of autophagy flux and mitochondrial biogenesis in the oxidative soleus muscle. We also observed increased basal autophagy flux and Bnip3 content without increases in autophagy protein expression in the plantaris muscle of sedentary muscle-specific Pgc-1α transgenic mice, a genetic model of augmented mitochondrial biogenesis. These findings reveal that endurance exercise training-induced increases in basal autophagy, including mitophagy, only take place if an enhanced oxidative phenotype is achieved. However, autophagy protein expression is mainly dictated by contractile activity independently of enhancements in oxidative phenotype. Exercise-trained mice heterozygous for the critical autophagy protein Atg6 showed attenuated increases of basal autophagy flux, mitochondrial content, and angiogenesis in skeletal muscle, along with impaired improvement of endurance capacity. These results demonstrate that increased basal autophagy is required for endurance exercise training-induced skeletal

  19. Mammalian autophagy is essential for hepatic and renal ketogenesis during starvation

    OpenAIRE

    Ayano Takagi; Shinji Kume; Motoyuki Kondo; Jun Nakazawa; Masami Chin-Kanasaki; Hisazumi Araki; Shin-ichi Araki; Daisuke Koya; Masakazu Haneda; Tokuhiro Chano; Taiji Matsusaka; Kenji Nagao; Yusuke Adachi; Lawrence Chan; Hiroshi Maegawa

    2016-01-01

    Autophagy is an intracellular degradation system activated, across species, by starvation. Although accumulating evidence has shown that mammalian autophagy is involved in pathogenesis of several modern diseases, its physiological role to combat starvation has not been fully clarified. In this study, we analysed starvation-induced gluconeogenesis and ketogenesis in mouse strains lacking autophagy in liver, skeletal muscle or kidney. Autophagy-deficiency in any tissue had no effect on gluconeo...

  20. Sinomenine Hydrochloride Protects against Polymicrobial Sepsis via Autophagy

    Directory of Open Access Journals (Sweden)

    Yu Jiang

    2015-01-01

    Full Text Available Sepsis, a systemic inflammatory response to infection, is the major cause of death in intensive care units (ICUs. The mortality rate of sepsis remains high even though the treatment and understanding of sepsis both continue to improve. Sinomenine (SIN is a natural alkaloid extracted from Chinese medicinal plant Sinomenium acutum, and its hydrochloride salt (Sinomenine hydrochloride, SIN-HCl is widely used to treat rheumatoid arthritis (RA. However, its role in sepsis remains unclear. In the present study, we investigated the role of SIN-HCl in sepsis induced by cecal ligation and puncture (CLP in BALB/c mice and the corresponding mechanism. SIN-HCl treatment improved the survival of BALB/c mice that were subjected to CLP and reduced multiple organ dysfunction and the release of systemic inflammatory mediators. Autophagy activities were examined using Western blotting. The results showed that CLP-induced autophagy was elevated, and SIN-HCl treatment further strengthened the autophagy activity. Autophagy blocker 3-methyladenine (3-MA was used to investigate the mechanism of SIN-HCl in vitro. Autophagy activities were determined by examining the autophagosome formation, which was shown as microtubule-associated protein light chain 3 (LC3 puncta with green immunofluorescence. SIN-HCl reduced lipopolysaccharide (LPS-induced inflammatory cytokine release and increased autophagy in peritoneal macrophages (PM. 3-MA significantly decreased autophagosome formation induced by LPS and SIN-HCl. The decrease of inflammatory cytokines caused by SIN-HCl was partially aggravated by 3-MA treatment. Taken together, our results indicated that SIN-HCl could improve survival, reduce organ damage, and attenuate the release of inflammatory cytokines induced by CLP, at least in part through regulating autophagy activities.

  1. Sinomenine hydrochloride protects against polymicrobial sepsis via autophagy.

    Science.gov (United States)

    Jiang, Yu; Gao, Min; Wang, Wenmei; Lang, Yuejiao; Tong, Zhongyi; Wang, Kangkai; Zhang, Huali; Chen, Guangwen; Liu, Meidong; Yao, Yongming; Xiao, Xianzhong

    2015-01-23

    Sepsis, a systemic inflammatory response to infection, is the major cause of death in intensive care units (ICUs). The mortality rate of sepsis remains high even though the treatment and understanding of sepsis both continue to improve. Sinomenine (SIN) is a natural alkaloid extracted from Chinese medicinal plant Sinomenium acutum, and its hydrochloride salt (Sinomenine hydrochloride, SIN-HCl) is widely used to treat rheumatoid arthritis (RA). However, its role in sepsis remains unclear. In the present study, we investigated the role of SIN-HCl in sepsis induced by cecal ligation and puncture (CLP) in BALB/c mice and the corresponding mechanism. SIN-HCl treatment improved the survival of BALB/c mice that were subjected to CLP and reduced multiple organ dysfunction and the release of systemic inflammatory mediators. Autophagy activities were examined using Western blotting. The results showed that CLP-induced autophagy was elevated, and SIN-HCl treatment further strengthened the autophagy activity. Autophagy blocker 3-methyladenine (3-MA) was used to investigate the mechanism of SIN-HCl in vitro. Autophagy activities were determined by examining the autophagosome formation, which was shown as microtubule-associated protein light chain 3 (LC3) puncta with green immunofluorescence. SIN-HCl reduced lipopolysaccharide (LPS)-induced inflammatory cytokine release and increased autophagy in peritoneal macrophages (PM). 3-MA significantly decreased autophagosome formation induced by LPS and SIN-HCl. The decrease of inflammatory cytokines caused by SIN-HCl was partially aggravated by 3-MA treatment. Taken together, our results indicated that SIN-HCl could improve survival, reduce organ damage, and attenuate the release of inflammatory cytokines induced by CLP, at least in part through regulating autophagy activities.

  2. Role of autophagy in disease resistance and hypersensitive response-associated cell death

    DEFF Research Database (Denmark)

    Hofius, Daniel; Munch, David; Bressendorff, Simon

    2011-01-01

    stress. At the same time, autophagy can contribute to cellular suicide. The concurrent engagement of autophagy in these processes during infection may sometimes mask its contribution to differing pro-survival and pro-death decisions. The importance of autophagy in innate immunity in mammals is well...

  3. A nonapoptotic role for CASP2/caspase 2: modulation of autophagy.

    Science.gov (United States)

    Tiwari, Meenakshi; Sharma, Lokendra K; Vanegas, Difernando; Callaway, Danielle A; Bai, Yidong; Lechleiter, James D; Herman, Brian

    2014-06-01

    CASP2/caspase 2 plays a role in aging, neurodegeneration, and cancer. The contributions of CASP2 have been attributed to its regulatory role in apoptotic and nonapoptotic processes including the cell cycle, DNA repair, lipid biosynthesis, and regulation of oxidant levels in the cells. Previously, our lab demonstrated CASP2-mediated modulation of autophagy during oxidative stress. Here we report the novel finding that CASP2 is an endogenous repressor of autophagy. Knockout or knockdown of CASP2 resulted in upregulation of autophagy in a variety of cell types and tissues. Reinsertion of Caspase-2 gene (Casp2) in mouse embryonic fibroblast (MEFs) lacking Casp2 (casp2(-/-)) suppresses autophagy, suggesting its role as a negative regulator of autophagy. Loss of CASP2-mediated autophagy involved AMP-activated protein kinase, mechanistic target of rapamycin, mitogen-activated protein kinase, and autophagy-related proteins, indicating the involvement of the canonical pathway of autophagy. The present study also demonstrates an important role for loss of CASP2-induced enhanced reactive oxygen species production as an upstream event in autophagy induction. Additionally, in response to a variety of stressors that induce CASP2-mediated apoptosis, casp2(-/-) cells demonstrate a further upregulation of autophagy compared with wild-type MEFs, and upregulated autophagy provides a survival advantage. In conclusion, we document a novel role for CASP2 as a negative regulator of autophagy, which may provide important insight into the role of CASP2 in various processes including aging, neurodegeneration, and cancer.

  4. Stimulation of autophagy by the p53 target gene Sestrin2.

    Science.gov (United States)

    Maiuri, Maria Chiara; Malik, Shoaib Ahmad; Morselli, Eugenia; Kepp, Oliver; Criollo, Alfredo; Mouchel, Pierre-Luc; Carnuccio, Rosa; Kroemer, Guido

    2009-05-15

    The oncosuppressor protein p53 regulates autophagy in a dual fashion. The pool of cytoplasmic p53 protein represses autophagy in a transcription-independent fashion, while the pool of nuclear p53 stimulates autophagy through the transactivation of specific genes. Here we report the discovery that Sestrin2, a novel p53 target gene, is involved in the induction of autophagy. Depletion of Sestrin2 by RNA interference reduced the level of autophagy in a panel of p53-sufficient human cancer cell lines responding to distinct autophagy inducers. In quantitative terms, Sestrin2 depletion was as efficient in preventing autophagy induction as was the depletion of Dram, another p53 target gene. Knockout of either Sestrin2 or Dram reduced autophagy elicited by nutrient depletion, rapamycin, lithium or thapsigargin. Moreover, autophagy induction by nutrient depletion or pharmacological stimuli led to an increase in Sestrin2 expression levels in p53-proficient cells. In strict contrast, the depletion of Sestrin2 or Dram failed to affect autophagy in p53-deficient cells and did not modulate the inhibition of baseline autophagy by a cytoplasmic p53 mutant that was reintroduced into p53-deficient cells. We conclude that Sestrin2 acts as a positive regulator of autophagy in p53-proficient cells.

  5. Evaluating the Effectiveness of GTM-1, Rapamycin, and Carbamazepine on Autophagy and Alzheimer Disease

    Science.gov (United States)

    Zhang, Lijuan; Wang, Lina; Wang, Run; Gao, Yuan; Che, Haoyue; Pan, Yonghua; Fu, Peng

    2017-01-01

    Background This study was proposed to compare the efficacy and safety of GTM-1, Rapamycin (Rap), and Carbamazepine (CBZ) in managing Alzheimer disease (AD). The impact of the above mentioned therapeutic drugs on autophagy was also investigated in our study. Material/Methods Firstly, 3×Tg AD mice were randomly allocated into 4 groups (each group with 10 mice), in which AD mice were separately treated with dimethylsulfoxide (DMSO, vehicle group), GTM-1 (6 mg/kg), Rap (1 mg/kg), and CBZ (100 mg/kg). Then spatial memory and learning ability of mice was tested using the Morris water maze. Routine blood tests were performed to evaluate the toxicity of these drugs. Amyloid-β42 (Aβ42) concentration was detected by ELISA and immunohistochemistry. Proteins related to autophagy were detected by Western blot. Results GTM-1, Rap, and CBZ significantly improved the spatial memory of 3×Tg AD mice compared to that in the vehicle group (all P<0.05). Moreover, this study revealed that CBZ dosage was related to toxicity in mice. All of the above drugs significantly increased the expression of LC3-II and reduced Aβ42 levels in hippocampi of 3×Tg AD mice (all P<0.05). On the other hand, neither GTM-1 nor CBZ had significant influence on the expression of proteins on the mTOR pathway. Conclusions GTM-1 can alleviate the AD syndrome by activating autophagy in a manner that is dependent on the mTOR pathway and it therefore can be considered as an alternative to Rap. PMID:28193995

  6. Heparin-binding Hemagglutinin of Mycobacterium tuberculosis Is an Inhibitor of Autophagy

    Science.gov (United States)

    Zheng, Qing; Li, Zhi; Zhou, Shan; Zhang, Qian; Zhou, Lei; Fu, Xiaorui; Yang, Liu; Ma, Yueyun; Hao, Xiaoke

    2017-01-01

    Airway epithelial cell is often the initial site of attack by pathogens, and cell death is commonly caused by internalization of Mycobacterium tuberculosis (Mtb). However, the mechanism of interaction between epithelial cells and Mtb is not well understood. In this study, we investigated the role of the heparin-binding hemagglutinin (HBHA) protein of Mtb in the function of epithelial cells. In particular, the autophagy of A549 cells was determined based on microtubule-associated protein 1 light chain 3 alpha (LC3) activity. Autophagosome formation was detected by Monodansylcadaverine (MDC) staining and immune fluorescence staining of LC3. Autophagy could be significantly suppressed by HBHA protein. In addition, the LDH assay results showed that HBHA treatment could induce death on A549 cells. To explore the form of cell death, we detected the activity of caspase-3 and LDH release of A549 cells in the presence or absence of caspase inhibitor Z-VAD-FMK. Results demonstrated that HBHA treatment could induce apoptosis of A549 cells. To further confirm these results, we constructed the recombinant Mycobacterium smegmatis (MS) expressing HBHA (rMS-HBHA) and explored the influence of rMS-HBHA on the function of A549 cells. rMS-HBHA infection significantly inhibited LC3 expression and the maturation of autophagosomes in A549 cells. Subsequently, we infected A549 cells with MS and detected the viability of intracellular MS by CFU counts. rMS-HBHA showed higher survival and replication capacity in A549 cells than those of the wild-type MS. Finally, infection of A549 cells with rMS-HBHA caused further apoptosis. These findings suggested that rMS-HBHA could inhibit autophagy, promote its survival and replication within A549 cells, and subsequently induce apoptosis on infected cells to facilitate infection.

  7. Pentosan polysulfate prevents glomerular hypertension and structural injury despite persisting hypertension in 5/6 nephrectomy rats.

    Science.gov (United States)

    Bobadilla, N A; Tack, I; Tapia, E; Sánchez-Lozada, L G; Santamaría, J; Jiménez, F; Striker, L J; Striker, G E; Herrera-Acosta, J

    2001-10-01

    Five/six nephrectomy induces systemic and glomerular hypertension, glomerulosclerosis, proteinuria, and tubulointerstitial fibrosis. Polysulfate pentosan (PPS) decreases mesangial proliferation and extracellular matrix accumulation. The aim of this study was to determine whether PPS prevents glomerular hemodynamic changes and renal damage. Micropuncture studies were performed in three groups of eight male Wistar rats. Two groups included rats with 5/6 nephrectomy-one of which was treated with PPS in drinking water (100 mg/kg body wt) and the second of which received normal drinking water-and the third group consisted of normal rats that served as controls. Five/six nephrectomy produced systemic hypertension, a 50% reduction in GFR, and a 67% increase in single-nephron GFR due to elevated glomerular pressure and single-nephron plasma flow as well as proteinuria. Hypertension persisted in PPS-treated animals. Despite a similar reduction in GFR, PPS prevented the rise in single-nephron GFR, glomerular capillary hydrostatic pressure, and proteinuria. By morphometry, glomerular volume was increased by 46% and mesangial area by 94%. Fractional glomerular capillary area decreased by 24%. PPS prevented these changes. Tubular dilatation, epithelial cell atrophy, and increased interstitial area were largely prevented by PPS, as was the interstitial inflammatory infiltrate. These results suggest that the renal protection conferred by PPS was mediated both by prevention of glomerular hypertension as well as suppression of the inflammatory response. It was postulated that this was partly due to the preservation of a greater fraction of functional nephrons.

  8. Crosstalk between Beclin-1-dependent autophagy and caspase-dependent apoptosis induced by tanshinone IIA in human osteosarcoma MG-63 cells

    Science.gov (United States)

    Ma, Kun; Zhang, Chuan; Huang, Man-Yu; Guo, Yan-Xing; Hu, Guo-Qiang

    2016-01-01

    The aim of the present study was to ascertain whether or not autophagy is induced by tanshinone IIA (TanIIA), and to explore the crosstalk between autophagy and apoptosis in regards to the antitumor effects of TanIIA on MG-63 cells and the potential mechanism. MG-63 cells were cultured in vitro with various concentrations of TanIIA (0, 2.5, 5, 10 and 20 mg/l) for 0, 24, 48 and 72 h, respectively. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to evaluate the inhibition of the proliferation of osteosarcoma MG-63 cells by TanIIA or in the presence/absence of chloroquine (CQ). Autophagic vacuoles and characteristic autophagosomes were observed by transmission electron microscopy (TEM). TanIIA-induced autophagy in MG-63 cells was confirmed by GFP-LC3 punctate fluorescence. The expression levels of apoptosis-related proteins caspase-3, caspase-8, caspase-9 and cleaved-PARP and autophagy-related proteins LC3II/LC3I and Beclin-1 were detected by western blotting. FITC-Annexin V/propidium iodide (PI) staining, flow cytometry and Hoechst 33258 staining were used to analyze the apoptotic rate. Fluorescence intensity of reactive oxygen species (ROS) was examined under a fluorescence microscope using an analysis software system. Cell proliferation was obviously inhibited by TanIIA in a dose- and time-dependent manner. Generation of autophagy was triggered by TanIIA (0–20 mg/l) treatment, and in a Beclin-1-dependent manner. Compared with the control group, the apoptosis ratio following treatment with 2.5 mg/l TanIIA failed to achieve statistical significance. Expression of caspase-3, -8 and -9, and cleaved-PARP in the other groups was gradually enhanced in dose-dependent manner. Our analysis also suggested that the influence of autophagy on TanIIA cytotoxicity had a phase effect; with low-dose drugs and shorter treatment periods, autophagy functioned as a damage repair mechanism. In conrast, when the cells were treated with higher doses of Tan

  9. Glomerular filtration rate in patients with gout and factors influencing the rate

    Directory of Open Access Journals (Sweden)

    F M Kudaeva

    2007-09-01

    Zaklyuchenie. Sushchestvuet zavisimost' mezhdu sostoyaniem azotovydelitel'noy funktsii pochek i vozrastom bol'nykh, dlitel'nost'yu i IT podagry. Nalichie AG, IBS, KhSN dostoverno ukhudshaet azotovydelitel'nuyu funktsiyu pochek pri podagre.

  10. Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR.

    Science.gov (United States)

    Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S; Liu, Qingsong; Zhang, Xin

    2016-01-01

    Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors.

  11. Polymorphisms in autophagy genes and susceptibility to tuberculosis.

    Directory of Open Access Journals (Sweden)

    Mario Songane

    Full Text Available Recent data suggest that autophagy is important for intracellular killing of Mycobacterium tuberculosis, and polymorphisms in the autophagy gene IRGM have been linked with susceptibility to tuberculosis (TB among African-Americans, and with TB caused by particular M. tuberculosis genotypes in Ghana. We compared 22 polymorphisms of 14 autophagy genes between 1022 Indonesian TB patients and 952 matched controls, and between patients infected with different M. tuberculosis genotypes, as determined by spoligotyping. The same autophagy polymorphisms were studied in correlation with ex-vivo production of TNF, IL-1β, IL-6, IL-8, IFN-γ and IL-17 in healthy volunteers. No association was found between TB and polymorphisms in the genes ATG10, ATG16L2, ATG2B, ATG5, ATG9B, IRGM, LAMP1, LAMP3, P2RX7, WIPI1, MTOR and ATG4C. Associations were found between polymorphisms in LAMP1 (p = 0.02 and MTOR (p = 0.02 and infection with the successful M. tuberculosis Beijing genotype. The polymorphisms examined were not associated with M. tuberculosis induced cytokines, except for a polymorphism in ATG10, which was linked with IL-8 production (p = 0.04. All associations found lost statistical significance after correction for multiple testing. This first examination of a broad set of polymorphisms in autophagy genes fails to show a clear association with TB, with M. tuberculosis Beijing genotype infection or with ex-vivo pro-inflammatory cytokine production.

  12. Ubiquitin and Autophagy%泛素与自噬

    Institute of Scientific and Technical Information of China (English)

    冯梅; 王莉新; 王易

    2011-01-01

    Protein degradation mediated by ubiquitin and autophagy are the basic mechanisms involved in cellular self-regulation. Ubiquitin may be involved in the process of autophagy by serving as a umversal recognition signal. Induction of autophagy can promote ubiquitination, thereby enhancing the degradation of substrate. This paper mainly focuses on the relation and the potential mutual regulation between ubiquitination and autophagy, as well as the phenomenon of programmed cell death that is associated with both ubiquitination and autophagy processes.%泛素调节的蛋白质降解过程和细胞的自噬现象都是细胞自我调节的基本机制.其中,泛素可能作为一种普遍的识别信号参与了自噬过程;而自噬的诱导又能促进泛素化作用,从而增强对底物的降解.本文着重探讨这两者间的关系及可能存在的相互调节作用,并兼及两者共同涉及的细胞程序性死亡现象.

  13. Mutant alpha-synuclein and autophagy in PC12 cells

    Institute of Scientific and Technical Information of China (English)

    Kangyong Liu; Chunfeng Liu; Chuancheng Ren; Yaping Yang; Liwei Shen; Xuezhong Li; Fen Wang; Zhenghong Qin

    2011-01-01

    Several studies have demonstrated that overexpression of mutant α-synuclein in PC12 cells is related to occurrence of autophagy.The present study established mutant a-synuclein (A30P)-transfected PC12 cells and treated them with the autophagy inducer rapamycin and autophagy inhibitor wortmannin, respectively.Results demonstrated that mutant o-synuclein resulted in cell death via autophagy and involved α-synuclein accumulation, membrane lipid oxidation, and loss of plasma membrane integrity.Mutant α-synuclein (A30P) also mediated toxicity of1-methyl-4-phenylpyridinium ion.Moreover, rapamycin inhibited a-synuclein aggregation, while wortmannin promoted o-synuclein aggregation and cell death.To further determine the role of autophagy due to mutant a-synuclein, the present study measured expression of microtubule-associated protein light chain 3.Results revealed that wortmannin and 1-methyl-4-phenylpyridinium ion inhibited expression of microtubule-associated protein light chain 3,while rapamycin promoted its expression.These findings suggested that abnormal aggregation of a-synuclein induced autophagic programmed cell death in PC12 cells.

  14. Blue-Print Autophagy: Potential for Cancer Treatment

    Directory of Open Access Journals (Sweden)

    Nadia Ruocco

    2016-07-01

    Full Text Available The marine environment represents a very rich source of biologically active compounds with pharmacological applications. This is due to its chemical richness, which is claiming considerable attention from the health science communities. In this review we give a general overview on the marine natural products involved in stimulation and inhibition of autophagy (a type of programmed cell death linked to pharmacological and pathological conditions. Autophagy represents a complex multistep cellular process, wherein a double membrane vesicle (the autophagosome captures organelles and proteins and delivers them to the lysosome. This natural and destructive mechanism allows the cells to degrade and recycle its cellular components, such as amino acids, monosaccharides, and lipids. Autophagy is an important mechanism used by cells to clear pathogenic organism and deal with stresses. Therefore, it has also been implicated in several diseases, predominantly in cancer. In fact, pharmacological stimulation or inhibition of autophagy have been proposed as approaches to develop new therapeutic treatments of cancers. In conclusion, this blue-print autophagy (so defined because it is induced and/or inhibited by marine natural products represents a new strategy for the future of biomedicine and of biotechnology in cancer treatment.

  15. All-you-can-eat: autophagy in neurodegeneration and neuroprotection

    Directory of Open Access Journals (Sweden)

    Jaeger Philipp A

    2009-04-01

    Full Text Available Abstract Autophagy is the major pathway involved in the degradation of proteins and organelles, cellular remodeling, and survival during nutrient starvation. Autophagosomal dysfunction has been implicated in an increasing number of diseases from cancer to bacterial and viral infections and more recently in neurodegeneration. While a decrease in autophagic activity appears to interfere with protein degradation and possibly organelle turnover, increased autophagy has been shown to facilitate the clearance of aggregation-prone proteins and promote neuronal survival in a number of disease models. On the other hand, too much autophagic activity can be detrimental as well and lead to cell death, suggesting the regulation of autophagy has an important role in cell fate decisions. An increasing number of model systems are now available to study the role of autophagy in the central nervous system and how it might be exploited to treat disease. We will review here the current knowledge of autophagy in the central nervous system and provide an overview of the various models that have been used to study acute and chronic neurodegeneration.

  16. Thyroid hormone stimulates hepatic lipid catabolism via activation of autophagy.

    Science.gov (United States)

    Sinha, Rohit Anthony; You, Seo-Hee; Zhou, Jin; Siddique, Mobin M; Bay, Boon-Huat; Zhu, Xuguang; Privalsky, Martin L; Cheng, Sheue-Yann; Stevens, Robert D; Summers, Scott A; Newgard, Christopher B; Lazar, Mitchell A; Yen, Paul M

    2012-07-01

    For more than a century, thyroid hormones (THs) have been known to exert powerful catabolic effects, leading to weight loss. Although much has been learned about the molecular mechanisms used by TH receptors (TRs) to regulate gene expression, little is known about the mechanisms by which THs increase oxidative metabolism. Here, we report that TH stimulation of fatty acid β-oxidation is coupled with induction of hepatic autophagy to deliver fatty acids to mitochondria in cell culture and in vivo. Furthermore, blockade of autophagy by autophagy-related 5 (ATG5) siRNA markedly decreased TH-mediated fatty acid β-oxidation in cell culture and in vivo. Consistent with this model, autophagy was altered in livers of mice expressing a mutant TR that causes resistance to the actions of TH as well as in mice with mutant nuclear receptor corepressor (NCoR). These results demonstrate that THs can regulate lipid homeostasis via autophagy and help to explain how THs increase oxidative metabolism.

  17. Blue-Print Autophagy: Potential for Cancer Treatment.

    Science.gov (United States)

    Ruocco, Nadia; Costantini, Susan; Costantini, Maria

    2016-07-21

    The marine environment represents a very rich source of biologically active compounds with pharmacological applications. This is due to its chemical richness, which is claiming considerable attention from the health science communities. In this review we give a general overview on the marine natural products involved in stimulation and inhibition of autophagy (a type of programmed cell death) linked to pharmacological and pathological conditions. Autophagy represents a complex multistep cellular process, wherein a double membrane vesicle (the autophagosome) captures organelles and proteins and delivers them to the lysosome. This natural and destructive mechanism allows the cells to degrade and recycle its cellular components, such as amino acids, monosaccharides, and lipids. Autophagy is an important mechanism used by cells to clear pathogenic organism and deal with stresses. Therefore, it has also been implicated in several diseases, predominantly in cancer. In fact, pharmacological stimulation or inhibition of autophagy have been proposed as approaches to develop new therapeutic treatments of cancers. In conclusion, this blue-print autophagy (so defined because it is induced and/or inhibited by marine natural products) represents a new strategy for the future of biomedicine and of biotechnology in cancer treatment.

  18. Inhibition of autophagy by TAB2 and TAB3.

    Science.gov (United States)

    Criollo, Alfredo; Niso-Santano, Mireia; Malik, Shoaib Ahmad; Michaud, Mickael; Morselli, Eugenia; Mariño, Guillermo; Lachkar, Sylvie; Arkhipenko, Alexander V; Harper, Francis; Pierron, Gérard; Rain, Jean-Christophe; Ninomiya-Tsuji, Jun; Fuentes, José M; Lavandero, Sergio; Galluzzi, Lorenzo; Maiuri, Maria Chiara; Kroemer, Guido

    2011-11-11

    Autophagic responses are coupled to the activation of the inhibitor of NF-κB kinase (IKK). Here, we report that the essential autophagy mediator Beclin 1 and TGFβ-activated kinase 1 (TAK1)-binding proteins 2 and 3 (TAB2 and TAB3), two upstream activators of the TAK1-IKK signalling axis, constitutively interact with each other via their coiled-coil domains (CCDs). Upon autophagy induction, TAB2 and TAB3 dissociate from Beclin 1 and bind TAK1. Moreover, overexpression of TAB2 and TAB3 suppresses, while their depletion triggers, autophagy. The expression of the C-terminal domain of TAB2 or TAB3 or that of the CCD of Beclin 1 competitively disrupts the interaction between endogenous Beclin 1, TAB2 and TAB3, hence stimulating autophagy through a pathway that requires endogenous Beclin 1, TAK1 and IKK to be optimally efficient. These results point to the existence of an autophagy-stimulatory 'switch' whereby TAB2 and TAB3 abandon inhibitory interactions with Beclin 1 to engage in a stimulatory liaison with TAK1.

  19. Autophagy is required for the activation of NFκB.

    Science.gov (United States)

    Criollo, Alfredo; Chereau, Fanny; Malik, Shoaib Ahmad; Niso-Santano, Mireia; Mariño, Guillermo; Galluzzi, Lorenzo; Maiuri, Maria Chiara; Baud, Véronique; Kroemer, Guido

    2012-01-01

    It is well-established that the activation of the inhibitor of NFκB (IκBα) kinase (IKK) complex is required for autophagy induction by multiple stimuli. Here, we show that in autophagy-competent mouse embryonic fibroblasts (MEFs), distinct autophagic triggers, including starvation, mTOR inhibition with rapamycin and p53 inhibition with cyclic pifithrin α lead to the activation of IKK, followed by the phosphorylation-dependent degradation of IκBα and nuclear translocation of NFκB. Remarkably, the NFκB signaling pathway was blocked in MEFs lacking either the essential autophagy genes Atg5 or Atg7. In addition, we found that tumor necrosis factor α (TNFα)-induced NFκB nuclear translocation is abolished in both Atg5- and Atg7-deficient MEFs. Similarly, the depletion of essential autophagy modulators, including ATG5, ATG7, Beclin 1 and VPS34, by RNA interference inhibited TNFα-driven NFκB activation in two human cancer cell lines. In conclusion, it appears that, at least in some instances, autophagy is required for NFκB activation, highlighting an intimate crosstalk between these two stress response signaling pathways.

  20. Salvianolic acid B inhibits autophagy and protects starving cardiac myocytes

    Science.gov (United States)

    Han, Xiao; Liu, Jian-xun; Li, Xin-zhi

    2011-01-01

    Aim: To investigate the protective or lethal role of autophagy and the effects of Salvianolic acid B (Sal B) on autophagy in starving myocytes. Methods: Cardiac myocytes were incubated under starvation conditions (GD) for 0, 1, 2, 3, and 6 h. Autophagic flux in starving cells was measured via chloroquine (3 μmol/L). After myocytes were treated with Sal B (50 μmol/L) in the presence or absence of chloroquine (3 μmol/L) under GD 3 h, the amount of LC3-II, the abundance of LC3-positive fluorescent dots in cells, cell viability and cellular ATP levels were determined using immunoblotting, immunofluorescence microscopy, MTT assay and luminometer, respectively. Moreover, electron microscopy (EM) and immunofluorescent duel labeling of LC3 and Caspase-8 were used to examine the characteristics of autophagy and apoptosis. Results: Immunoblot analysis showed that the amount of LC3-II in starving cells increased in a time-dependent manner accompanied by increased LC3-positive fluorescence and decreased cell viability and ATP content. Sal B (50 μmol/L) inhibited the increase in LC3-II, reduced the abundance of LC3 immunofluorescence and intensity of Caspase-8 fluorescence, and enhanced cellular viability and ATP levels in myocytes under GD 3 h, regardless of whether chloroquine was present. Conclusion: Autophagy induced by starvation for 3 h led to cell injury. Sal B protected starving cells by blocking the early stage of autophagic flux and inhibiting apoptosis that occurred during autophagy. PMID:21113177

  1. Boosting autophagy in the diabetic heart: a translational perspective.

    Science.gov (United States)

    Sciarretta, Sebastiano; Boppana, V Subbarao; Umapathi, Mahaa; Frati, Giacomo; Sadoshima, Junichi

    2015-10-01

    Diabetes, obesity, and dyslipidemia are main risk factors that promote the development of cardiovascular diseases. These metabolic abnormalities are frequently found to be associated together in a highly morbid clinical condition called metabolic syndrome. Metabolic derangements promote endothelial dysfunction, atherosclerotic plaque formation and rupture, cardiac remodeling and dysfunction. This evidence strongly encourages the elucidation of the mechanisms through which obesity, diabetes, and metabolic syndrome induce cellular abnormalities and dysfunction in order to discover new therapeutic targets and strategies for their prevention and treatment. Numerous studies employing both dietary and genetic animal models of obesity and diabetes have demonstrated that autophagy, an intracellular system for protein degradation, is impaired in the heart under these conditions. This suggests that autophagy reactivation may represent a future potential therapeutic intervention to reduce cardiac maladaptive alterations in patients with metabolic derangements. In fact, autophagy is a critical mechanism to preserve cellular homeostasis and survival. In addition, the physiological activation of autophagy protects the heart during stress, such as acute ischemia, starvation, chronic myocardial infarction, pressure overload, and proteotoxic stress. All these aspects will be discussed in our review article together with the potential ways to reactivate autophagy in the context of obesity, metabolic syndrome, and diabetes.

  2. Autophagy mediates tolerance to Staphylococcus aureus alpha-toxin.

    Science.gov (United States)

    Maurer, Katie; Reyes-Robles, Tamara; Alonzo, Francis; Durbin, Joan; Torres, Victor J; Cadwell, Ken

    2015-04-01

    Resistance and tolerance are two defense strategies employed by the host against microbial threats. Autophagy-mediated degradation of bacteria has been extensively described as a major resistance mechanism. Here we find that the dominant function of autophagy proteins during infections with the epidemic community-associated methicillin-resistant Staphylococcus aureus USA300 is to mediate tolerance rather than resistance. Atg16L1 hypomorphic mice (Atg16L1(HM)), which have reduced autophagy, were highly susceptible to lethality in both sepsis and pneumonia models of USA300 infection. Autophagy confers protection by limiting the damage caused by α-toxin, particularly to endothelial cells. Remarkably, Atg16L1(HM) mice display enhanced survival rather than susceptibility upon infection with α-toxin-deficient S. aureus. These results identify an essential role for autophagy in tolerance to Staphylococcal disease and highlight how a single virulence factor encoded by a pathogen can determine whether a given host factor promotes tolerance or resistance.

  3. Evidence for selective mitochondrial autophagy and failure in aging.

    Science.gov (United States)

    Cavallini, Gabriella; Donati, Alessio; Taddei, Michele; Bergamini, Ettore

    2007-01-01

    Autophagy is a major intracellular degradation/recycling system ubiquitous in eukaryotic cells. It contributes to the turnover of cellular components by delivering portions of the cytoplasm and organelles to lysosomes, where they are digested. Starvation-induced autophagy is required for maintaining an amino acid pool for gluconeogenesis and for the synthesis of proteins essential to survival under starvation conditions. In addition, autophagy plays an important role in the degradation of excess or injured organelles, including mitochondria. To test the hypothesis of an involvement of a decrease in autophagy in the process of aging, we explored the antiaging effects of pharmacological stimulation of autophagy on the age-dependent accumulation of 8-OHdG-rich mitochondria in rat liver. Male 3-month and 16-month-old 24 hours-fasted Sprague Dawley rats were injected with the antilipolytic agent [3,5-dimethylpyrazole (DMP)] intraperitoneally. Results showed that drug injection rescued older cells from the accumulation of 8-OHdG in the mtDNA in less than 6 hours, but no significant decrease in the level of cytochrome c oxidase activity was observed. Together, these data provide indirect evidence that 8-OHdG might accumulate in a small pool of mitochondria with increasing age rather than be degraded by the autophagic machinery selectively.

  4. An effector of the Irish potato famine pathogen antagonizes a host autophagy cargo receptor

    Science.gov (United States)

    Dagdas, Yasin F; Belhaj, Khaoula; Maqbool, Abbas; Chaparro-Garcia, Angela; Pandey, Pooja; Petre, Benjamin; Tabassum, Nadra; Cruz-Mireles, Neftaly; Hughes, Richard K; Sklenar, Jan; Win, Joe; Menke, Frank; Findlay, Kim; Banfield, Mark J; Kamoun, Sophien; Bozkurt, Tolga O

    2016-01-01

    Plants use autophagy to safeguard against infectious diseases. However, how plant pathogens interfere with autophagy-related processes is unknown. Here, we show that PexRD54, an effector from the Irish potato famine pathogen Phytophthora infestans, binds host autophagy protein ATG8CL to stimulate autophagosome formation. PexRD54 depletes the autophagy cargo receptor Joka2 out of ATG8CL complexes and interferes with Joka2's positive effect on pathogen defense. Thus, a plant pathogen effector has evolved to antagonize a host autophagy cargo receptor to counteract host defenses. DOI: http://dx.doi.org/10.7554/eLife.10856.001 PMID:26765567

  5. PML at Mitochondria-Associated Membranes Is Critical for the Repression of Autophagy and Cancer Development

    Directory of Open Access Journals (Sweden)

    Sonia Missiroli

    2016-08-01

    Full Text Available The precise molecular mechanisms that coordinate apoptosis and autophagy in cancer remain to be determined. Here, we provide evidence that the tumor suppressor promyelocytic leukemia protein (PML controls autophagosome formation at mitochondria-associated membranes (MAMs and, thus, autophagy induction. Our in vitro and in vivo results demonstrate how PML functions as a repressor of autophagy. PML loss promotes tumor development, providing a growth advantage to tumor cells that use autophagy as a cell survival strategy during stress conditions. These findings demonstrate that autophagy inhibition could be paired with a chemotherapeutic agent to develop anticancer strategies for tumors that present PML downregulation.

  6. Crosstalk between Autophagy and Apoptosis: Potential and Emerging Therapeutic Targets for Cardiac Diseases

    Directory of Open Access Journals (Sweden)

    Meng Li

    2016-03-01

    Full Text Available Autophagy is a cell survival process which is related to breaking down and reusing cytoplasm components. Moreover, autophagy regulates cell death under certain conditions. Apoptosis has the characteristics of chromatin agglutination and the shrinking of nuclear and apoptosis body form. Even if the mechanisms of autophagy and apoptosis have differences, some proteins modulate both autophagy and apoptosis. Crosstalk between them exists. This review highlights recent advances in the interaction of autophagy and apoptosis and its importance in the development of cardiovascular diseases.

  7. Autophagy, Inflammation, and Immunity: A Troika Governing Cancer and Its Treatment.

    Science.gov (United States)

    Zhong, Zhenyu; Sanchez-Lopez, Elsa; Karin, Michael

    2016-07-14

    Autophagy, a cellular waste disposal process, has well-established tumor-suppressive properties. New studies indicate that, in addition to its cell-autonomous anti-tumorigenic functions, autophagy inhibits cancer development by orchestrating inflammation and immunity. While attenuating tumor-promoting inflammation, autophagy enhances the processing and presentation of tumor antigens and thereby stimulates anti-tumor immunity. Although cancer cells can escape immunosurveillance by tuning down autophagy, certain chemotherapeutic agents with immunogenic properties may enhance anti-tumor immunity by inducing autophagic cell death. Understanding the intricate and complex relationships within this troika and how they are affected by autophagy enhancing drugs should improve the efficacy of cancer immunotherapy.

  8. Additive effect of polymorphisms in the β2 -adrenoceptor and NADPH oxidase p22 phox genes contributes to the loss of estimated glomerular filtration rate in Chinese.

    Science.gov (United States)

    Wang, Tao; Zhang, Yan; Ma, JingTao; Feng, Zhen; Niu, Kai; Liu, Bing

    2014-09-01

    Because increased oxidative stress may mediate the detrimental actions of enhanced sympathetic nervous activity on renal function and vice versa, we investigated the effect of the polymorphic Arg16Gly in the β2 -adrenoceptor (ADRB2) gene, Trp64Arg in the β3 -adrenoceptor (ADRB3) gene and C242T in the NADPH oxidase p22phox (CYBA) gene on estimated glomerular filtration rate (eGFR) in a Chinese population. Initially recruited from different outpatient services of HeBei General Hospital in northern China, 668 individuals were finally included in the study, with complete demographic information. Laboratory tests were performed and estimated glomerular filtration rate (eGFR) was derived from the Modification of Diet in Renal Disease (MDRD) equation for the Chinese population. Plasma noradrenaline levels and genotype were determined by HPLC and the TaqMan method, respectively. Only across the Arg16Gly polymorphism did eGFR show significant difference: it was lower in individuals with the Gly16Gly variation, who also had the highest plasma noradrenaline levels. This polymorphism remained a significant determinant of eGFR after multivariate analysis. Of importance, the multifactor dimensionality reduction method further detected a significant synergism between the Arg16Gly and C242T polymorphisms in reducing eGFR. These observations clarify the effects of the studied polymorphisms on eGFR and exemplify gene-gene interactions influencing renal function.

  9. MAVS maintains mitochondrial homeostasis via autophagy

    Science.gov (United States)

    Sun, Xiaofeng; Sun, Liwei; Zhao, Yuanyuan; Li, Ying; Lin, Wei; Chen, Dahua; Sun, Qinmiao

    2016-01-01

    Mitochondrial antiviral signalling protein (MAVS) acts as a critical adaptor protein to transduce antiviral signalling by physically interacting with activated RIG-I and MDA5 receptors. MAVS executes its functions at the outer membrane of mitochondria to regulate downstream antiviral signalling, indicating that the mitochondria provides a functional platform for innate antiviral signalling transduction. However, little is known about whether and how MAVS-mediated antiviral signalling contributes to mitochondrial homeostasis. Here we show that the activation of MAVS is sufficient to induce autophagic signalling, which may mediate the turnover of the damaged mitochondria. Importantly, we find MAVS directly interacts with LC3 through its LC3-binding motif ‘YxxI’, suggesting that MAVS might act as an autophagy receptor to mediate mitochondrial turnover upon excessive activation of RLR signalling. Furthermore, we provide evidence that both MAVS self-aggregation and its interaction with TRAF2/6 proteins are important for MAVS-mediated mitochondrial turnover. Collectively, our findings suggest that MAVS acts as a potential receptor for mitochondria-associated autophagic signalling to maintain mitochondrial homeostasis. PMID:27551434

  10. ATG8 Expansion: A Driver of Selective Autophagy Diversification?

    Science.gov (United States)

    Kellner, Ronny; De la Concepcion, Juan Carlos; Maqbool, Abbas; Kamoun, Sophien; Dagdas, Yasin F

    2017-03-01

    Selective autophagy is a conserved homeostatic pathway that involves engulfment of specific cargo molecules into specialized organelles called autophagosomes. The ubiquitin-like protein ATG8 is a central player of the autophagy network that decorates autophagosomes and binds to numerous cargo receptors. Although highly conserved across eukaryotes, ATG8 diversified from a single protein in algae to multiple isoforms in higher plants. We present a phylogenetic overview of 376 ATG8 proteins across the green plant lineage that revealed family-specific ATG8 clades. Because these clades differ in fixed amino acid polymorphisms, they provide a mechanistic framework to test whether distinct ATG8 clades are functionally specialized. We propose that ATG8 expansion may have contributed to the diversification of selective autophagy pathways in plants.

  11. Autophagy deficiency promotes beta-lactam production in Penicillium chrysogenum.

    Science.gov (United States)

    Bartoszewska, Magdalena; Kiel, Jan A K W; Bovenberg, Roel A L; Veenhuis, Marten; van der Klei, Ida J

    2011-02-01

    We have investigated the significance of autophagy in the production of the β-lactam antibiotic penicillin (PEN) by the filamentous fungus Penicillium chrysogenum. In this fungus PEN production is compartmentalized in the cytosol and in peroxisomes. We demonstrate that under PEN-producing conditions significant amounts of cytosolic and peroxisomal proteins are degraded via autophagy. Morphological analysis, based on electron and fluorescence microscopy, revealed that this phenomenon might contribute to progressive deterioration of late subapical cells. We show that deletion of the P. chrysogenum ortholog of Saccharomyces cerevisiae serine-threonine kinase atg1 results in impairment of autophagy. In P. chrysogenum atg1 cells, a distinct delay in cell degeneration is observed relative to wild-type cells. This phenomenon is associated with an increase in the enzyme levels of the PEN biosynthetic pathway and enhanced production levels of this antibacterial compound.

  12. Identification of an autophagy defect in smokers' alveolar macrophages.

    Science.gov (United States)

    Monick, Martha M; Powers, Linda S; Walters, Katherine; Lovan, Nina; Zhang, Michael; Gerke, Alicia; Hansdottir, Sif; Hunninghake, Gary W

    2010-11-01

    Alveolar macrophages are essential for clearing bacteria from the alveolar surface and preventing microbe-induced infections. It is well documented that smokers have an increased incidence of infections, in particular lung infections. Alveolar macrophages accumulate in smokers' lungs, but they have a functional immune deficit. In this study, we identify an autophagy defect in smokers' alveolar macrophages. Smokers' alveolar macrophages accumulate both autophagosomes and p62, a marker of autophagic flux. The decrease in the process of autophagy leads to impaired protein aggregate clearance, dysfunctional mitochondria, and defective delivery of bacteria to lysosomes. This study identifies the autophagy pathway as a potential target for interventions designed to decrease infection rates in smokers and possibly in individuals with high environmental particulate exposure.

  13. Modelling autophagy selectivity by receptor clustering on peroxisomes

    CERN Document Server

    Brown, Aidan I

    2016-01-01

    When subcellular organelles are degraded by autophagy, typically some, but not all, of each targeted organelle type are degraded. Autophagy selectivity must not only select the correct type of organelle, but must discriminate between individual organelles of the same kind. In the context of peroxisomes, we use computational models to explore the hypothesis that physical clustering of autophagy receptor proteins on the surface of each organelle provides an appropriate all-or-none signal for degradation. The pexophagy receptor proteins NBR1 and p62 are well characterized, though only NBR1 is essential for pexophagy (Deosaran {\\em et al.}, 2013). Extending earlier work by addressing the initial nucleation of NBR1 clusters on individual peroxisomes, we find that larger peroxisomes nucleate NBR1 clusters first and lose them due to competitive coarsening last, resulting in significant size-selectivity favouring large peroxisomes. This effect can explain the increased catalase signal that results from experimental s...

  14. Methamphetamine-induced toxicity: The role of autophagy?

    Science.gov (United States)

    Roohbakhsh, Ali; Shirani, Kobra; Karimi, Gholamreza

    2016-12-25

    Methamphetamine (METH) is a highly potent and addictive drug with major medical, psychiatric, cognitive, socioeconomic, and legal consequences. It is well absorbed following different routes of administration and distributed throughout the body. METH is known as psychomotor stimulant with potent physiological outcomes on peripheral and central nervous systems, resulting in physical and psychological disorders. Autophagy is a highly conserved and regulated catabolic pathway which is critical for maintaining cellular energy homeostasis and regulating cell growth. The mechanism of autophagy has attracted considerable attention in the last few years because of its recognition as a vital arbiter of death/survival decisions in cells and as a critical defense mechanism in undesirable physiological conditions. The purpose of the current article was to review available evidence to find a relationship between METH toxicity and mechanisms associated with autophagy in different organs.

  15. Saturated fatty acids modulate autophagy's proteins in the hypothalamus.

    Science.gov (United States)

    Portovedo, Mariana; Ignacio-Souza, Letícia M; Bombassaro, Bruna; Coope, Andressa; Reginato, Andressa; Razolli, Daniela S; Torsoni, Márcio A; Torsoni, Adriana S; Leal, Raquel F; Velloso, Licio A; Milanski, Marciane

    2015-01-01

    Autophagy is an important process that regulates cellular homeostasis by degrading dysfunctional proteins, organelles and lipids. In this study, the hypothesis that obesity could lead to impairment in hypothalamic autophagy in mice was evaluated by examining the hypothalamic distribution and content of autophagic proteins in animal with obesity induced by 8 or 16 weeks high fat diet to induce obesity and in response to intracerebroventricular injections of palmitic acid. The results showed that chronic exposure to a high fat diet leads to an increased expression of inflammatory markers and downregulation of autophagic proteins. In obese mice, autophagic induction leads to the downregulation of proteins, such as JNK and Bax, which are involved in the stress pathways. In neuron cell-line, palmitate has a direct effect on autophagy even without inflammatory activity. Understanding the cellular and molecular bases of overnutrition is essential for identifying new diagnostic and therapeutic targets for obesity.

  16. Autophagy and tumors%自噬与肿瘤

    Institute of Scientific and Technical Information of China (English)

    李姣; 范松青

    2013-01-01

    近期研究发现自噬不仅对细胞内自我平衡调节起着重要作用,而且在肿瘤的发生发展中起着双刃剑的作用.研究自噬的分子机制以及自噬与肿瘤的关系对肿瘤防治有重大意义.%Recent studies show that autophagy ont only plays an important role in maintaining homeostasis in cells,but also palys a double role in the tumorigenesis and development of cancer.Studying the molecular mechanisms of autophagy and the relationship between autophagy and cancer have great significance for cancer treatment and prevention.

  17. Methylprednisolone exerts neuroprotective effects by regulating autophagy and apoptosis

    Institute of Scientific and Technical Information of China (English)

    Wei Gao; Shu-rui Chen; Meng-yao Wu; Kai Gao; Yuan-long Li; Hong-yu Wang; Chen-yuan Li; Hong Li

    2016-01-01

    Methylprednisolone markedly reduces autophagy and apoptosis after secondary spinal cord injury. Here, we investigated whether pretreat-ment of cells with methylprednisolone would protect neuron-like cells from subsequent oxidative damagevia suppression of autophagy and apoptosis. Cultured N2a cells were pretreated with 10 µM methylprednisolone for 30 minutes, then exposed to 100 µM H2O2 for 24 hours. Inverted phase contrast microscope images, MTT assay, lfow cytometry and western blot results showed that, compared to cells ex-posed to 100 µM H2O2 alone, cells pretreated with methylprednisolone had a signiifcantly lower percentage of apoptotic cells, maintained a healthy morphology, and showed downregulation of autophagic protein light chain 3B and Beclin-1 protein expression. These ifndings indicate that methylprednisolone exerted neuroprotective effects against oxidative damage by suppressing autophagy and apoptosis.

  18. Impaired autoregulation of glomerular filtration rate in type 1 (insulin-dependent) diabetic patients with nephropathy

    DEFF Research Database (Denmark)

    Parving, H H; Kastrup, Helge; Smidt, U M

    1984-01-01

    The effect of acute lowering of arterial blood pressure upon kidney function in nephropathy was studied in 13 patients with long-term Type 1 (insulin-dependent) diabetes. Ten normal subjects (six normotensive and four hypertensive) and five short-term Type 1 diabetic patients without nephropathy...... micrograms) or saline (0.154 mmol/l). The arterial blood pressure was similar in the diabetic patients with nephropathy (mean 136 +/- 11 divided by 88 +/- mmHg) and in the non-diabetic control subjects (mean 140 +/- 25 divided by 92 +/- 15 mmHg). The clonidine injection induced similar reductions in mean...... excretion declined from 1707 to 938 micrograms/min (p less than 0.01) in the patients with diabetic nephropathy. Our results suggest that an intrinsic vascular (arteriolar) mechanism underlying the normal autoregulation of glomerular filtration rate, i.e. the relative constancy of glomerular filtration rate...

  19. Sieve plugs in fenestrae of glomerular capillaries--site of the filtration barrier?

    DEFF Research Database (Denmark)

    Rostgaard, Jørgen; Qvortrup, Klaus

    2002-01-01

    The exact location of the filtration barrier of the glomerular capillary wall, which consists of an endothelium, a basement membrane and a visceral epithelium, has not yet been determined. Apparent discrepancies between different investigators in the past could be explained if postmortem...... artifactual tissue changes, due to subnormal blood pressure or anoxia, have taken place in the endothelium before the tissue and tracers have been sufficiently fixed and immobilized by the fixative. To test this supposition, a new method of fixation, which includes a technique to maintain a physiological...... perfusion pressure and a fixative composed of an oxygen-carrying blood substitute fluid containing glutaraldehyde, was employed combined with contrast enhancement. New observations of the glomerular capillary wall revealed that filamentous plugs (about 90 nm in height) filled the capillary fenestrae...

  20. Pathology of nondiabetic glomerular disease among adult Iraqi patients from a single center

    Directory of Open Access Journals (Sweden)

    Hashim Al-Saedi Ali

    2009-01-01

    Full Text Available Almost all forms of glomerular diseases have been reported in diabetics. In a recent series, 12% of those with type I and 27% of those with type II diabetes were found to have non diabetic renal disease. We studied 80 adult diabetic Iraqi patients who were diagnosed with glo-merular disease on native kidney biopsies from January 2000 to April 2008. Membranoproliferative GN was seen in 32 patients (40%, Focal and Segmental glomerulosclerosis in 16 patients (20%, Membranous nephropathy in 20 patients (25%, Minimal change disease in 8 patients (10%, Renal amyloidosis in 4 patients (5%. In conclusion Membranoproliferative GN was the most common histological diagnosis in our diabetic patients undergoing renal biopsy.

  1. EFFECTS OF PDGF-BB ON INTRACELLULAR CALCIUM CONCENTRATION AND PROLIFERATION IN CULTURED GLOMERULAR MESANGIAL CELLS

    Institute of Scientific and Technical Information of China (English)

    WEN Li-ping; ZHANG Chong; BIAN Fan; ZOU Jun; JIANG Geng-ru; ZHU Han-wei

    2006-01-01

    Objective To investigate the relationship between the alteration of intracellular calcium concentration and proliferation in cultured glomerular mesangial cells. Methods Rat mesangial cells were cultured.Intracellular calcium concentrations were measured by confocal Laser Scanning Microscopy and Fura-3 fluorescence dyeing techniques. Cell growth was measured by MTT assay. Results PDGF-BB increased intracellular calcium concentrations in a dose-dependent manner, and at the same time promote the proliferation of mesangial cells. After preincubation with calcium channel blocker nifedipine or angiotensin converting enzyme inhibitor captopril, both the increase of intracellular calcium concentrations and cell proliferations induced by PDGF-BB were inhibited. Tripterigium Wilfordii Glycosides (TMG) significantly inhibited the mesangial cell proliferations, but it had no significant effect on intracellular calcium concentrations. Conclusion There was a positive relationship between the elevation of intracellular calcium concentration and cell proliferation in glomerular mesangial cells, but the increase of in- tracellular calcium concentrations wasn't the only way for proliferation.

  2. Autocrine growth regulation of human glomerular mesangial cells is primarily mediated by basic fibroblast growth factor.

    OpenAIRE

    Francki, A.; Uciechowski, P.; Floege, J; von der Ohe, J.; Resch, K.; Radeke, H. H.

    1995-01-01

    For various forms of human glomerulonephritis a close relationship between inflammatory injury and a local mesangial proliferative response has been described. Herein, we used primary cultures of human glomerular mesangial cells (HMCs) from five different donors to determine the autocrine growth-inducing capacity of their supernatants after stimulation with different cytokines and lipopolysaccharide (LPS) to determine whether this effect is due to basic fibroblast growth factor (bFGF). The ba...

  3. Estimating total glomerular number in human kidneys with a physical disector/fractionator combination:

    OpenAIRE

    Kelli J Johnson; Wreford, Nigel G.; Hoy, Wendy E.; John F Bertram

    2000-01-01

    End-stage renal disease (ESRD) has emerged as a major health issue for Australian Aborigines. This phenomenon is paralleled in other populations that have adopted a Westernised lifestyle, including African Americans. It has been suggested that abnormal glomerular hypertrophy (glomerulomegaly) is an important predisposing factor for ESRD. The pathogenesis of glomerulomegaly remains unknown. It may represent a compensatory hypertrophic response to decreased nephron endowment during fetal develo...

  4. Decrease of Glomerular Filtration Rate may be Attributed to the Microcirculation Damage in Renal Artery Stenosis

    Institute of Scientific and Technical Information of China (English)

    Hao-Jian Dong; Cheng Huang; De-Mou Luo; Jing-Guang Ye; Jun-Qing Yang; Guang Li; Jian-Fang Luo

    2015-01-01

    Background:The decrease of glomerular filtration rate has been theoretically supposed to be the result of low perfusion in renal artery stenosis (RAS).But the gap between artery stenosis and the glomerular filtration ability is still unclear.Methods:Patients with selective renal artery angiogram were divided by the degree of renal artery narrowing,level of estimated glomerular filtration rate (eGFR),respectively.The different levels of eGFR,renal microcirculation markers,and RAS severity were compared with each other,to determine the relationships among them.Results:A total of 215 consecutive patients were enrolled in the prospective cohort study.Concentrations of microcirculation markers had no significant difference between RAS group (RAS ≥ 50%) and no RAS group (RAS < 50%) or did not change correspondingly to RAS severity.The value of eGFR in RAS group was lower than that in the no RAS group,but it did not decline parallel to the progressive severity of RAS.The microcirculation markers presented integral difference if grouped by different eGFR level with negative tendency,especially that plasma cystatin C (cysC) and urinary microalbumin to creatinine ratio (mACR) increased with the deterioration of eGFR,with strong (r =-0.713,P < 0.001) and moderate (r =-0.580,P < 0.001) correlations.In the subgroup analysis of severe RAS (RAS ≥ 80%),the levels of plasma cysC and urinary mACR demonstrated stronger negative associations with eGFR,(r =-0.827,P < 0.001) and (r =-0.672,P < 0.001) correlations,respectively.Conclusions:Severity of RAS could not accurately predict the value of eGFR,whereas microcirculation impairment may substantially contribute to the glomerular filtration loss in patients with RAS.

  5. Progression of glomerular filtration rate reduction determined in conscious Dahl salt-sensitive hypertensive rats.

    Science.gov (United States)

    Cowley, Allen W; Ryan, Robert P; Kurth, Terry; Skelton, Meredith M; Schock-Kusch, Daniel; Gretz, Norbert

    2013-07-01

    Sequential changes in glomerular filtration rate during development of hypertension in the conscious Dahl salt-sensitive rats were determined using a new method for measurement. Using a miniaturized device, disappearance curves of fluorescein isothiocyanate-sinistrin were measured by transcutaneous excitation and real-time detection of the emitted light through the skin. Rats with implanted femoral venous catheters (dye injection and sampling) and carotid catheters (mean arterial pressure by telemetry) were studied, while maintained on a 0.4% NaCl diet and on days 2, 5, 7, 14, and 21 after switching to 4.0% (high-salt [HS]) diet. A separate group of rats were maintained on 0.4% for 21 days as a time control. Mean arterial pressure rose progressively from the last day of 0.4% (130±2 mm Hg) reaching significance by day 5 of HS and averaged 162±7 mm Hg by day 21. Urine albumin excretion was significantly elevated (×3) by day 7 of HS in Dahl salt-sensitive rats. Glomerular filtration rate reduced on day 14 of HS falling from 1.53±0.06 mL/min per 100 g body weight to 1.27±0.04. By day 21, glomerular filtration rate had fallen 28% to 1.1±0.04 mL/min per 100 g (t(1/2) 28.4±1.1 minute.) No significant reductions of creatinine clearance were observed throughout the study in response to HS demonstrating the insensitivity of creatinine clearance measurements even with creatinine measured using mass spectrometry. We conclude that the observed reduction of glomerular filtration rate was a consequence and not a cause of the hypertension and that this noninvasive approach could be used in these conscious Dahl salt-sensitive rats for a longitudinal assessment of renal function.

  6. Decrease of Glomerular Filtration Rate may be Attributed to the Microcirculation Damage in Renal Artery Stenosis

    Directory of Open Access Journals (Sweden)

    Hao-Jian Dong

    2015-01-01

    Full Text Available Background: The decrease of glomerular filtration rate has been theoretically supposed to be the result of low perfusion in renal artery stenosis (RAS. But the gap between artery stenosis and the glomerular filtration ability is still unclear. Methods: Patients with selective renal artery angiogram were divided by the degree of renal artery narrowing, level of estimated glomerular filtration rate (eGFR, respectively. The different levels of eGFR, renal microcirculation markers, and RAS severity were compared with each other, to determine the relationships among them. Results: A total of 215 consecutive patients were enrolled in the prospective cohort study. Concentrations of microcirculation markers had no significant difference between RAS group (RAS ≥ 50% and no RAS group (RAS < 50% or did not change correspondingly to RAS severity. The value of eGFR in RAS group was lower than that in the no RAS group, but it did not decline parallel to the progressive severity of RAS. The microcirculation markers presented integral difference if grouped by different eGFR level with negative tendency, especially that plasma cystatin C (cysC and urinary microalbumin to creatinine ratio (mACR increased with the deterioration of eGFR, with strong (r = −0.713, P < 0.001 and moderate (r = −0.580, P < 0.001 correlations. In the subgroup analysis of severe RAS (RAS ≥ 80%, the levels of plasma cysC and urinary mACR demonstrated stronger negative associations with eGFR, (r = −0.827, P < 0.001 and (r = −0.672, P < 0.001 correlations, respectively. Conclusions: Severity of RAS could not accurately predict the value of eGFR, whereas microcirculation impairment may substantially contribute to the glomerular filtration loss in patients with RAS.

  7. Glomerular disease search filters for Pubmed, Ovid Medline, and Embase: a development and validation study

    Directory of Open Access Journals (Sweden)

    Hildebrand Ainslie M

    2012-06-01

    Full Text Available Abstract Background Tools to enhance physician searches of Medline and other bibliographic databases have potential to improve the application of new knowledge in patient care. This is particularly true for articles about glomerular disease, which are published across multiple disciplines and are often difficult to track down. Our objective was to develop and test search filters for PubMed, Ovid Medline, and Embase that allow physicians to search within a subset of the database to retrieve articles relevant to glomerular disease. Methods We used a diagnostic test assessment framework with development and validation phases. We read a total of 22,992 full text articles for relevance and assigned them to the development or validation set to define the reference standard. We then used combinations of search terms to develop 997,298 unique glomerular disease filters. Outcome measures for each filter included sensitivity, specificity, precision, and accuracy. We selected optimal sensitive and specific search filters for each database and applied them to the validation set to test performance. Results High performance filters achieved at least 93.8% sensitivity and specificity in the development set. Filters optimized for sensitivity reached at least 96.7% sensitivity and filters optimized for specificity reached at least 98.4% specificity. Performance of these filters was consistent in the validation set and similar among all three databases. Conclusions PubMed, Ovid Medline, and Embase can be filtered for articles relevant to glomerular disease in a reliable manner. These filters can now be used to facilitate physician searching.

  8. Atrasentan Reduces Albuminuria by Restoring the Glomerular Endothelial Glycocalyx Barrier in Diabetic Nephropathy.

    Science.gov (United States)

    Boels, Margien G S; Avramut, M Cristina; Koudijs, Angela; Dane, Martijn J C; Lee, Dae Hyun; van der Vlag, Johan; Koster, Abraham J; van Zonneveld, Anton Jan; van Faassen, Ernst; Gröne, Hermann-Josef; van den Berg, Bernard M; Rabelink, Ton J

    2016-08-01

    Atrasentan, a selective endothelin A receptor antagonist, has been shown to reduce albuminuria in type 2 diabetes. We previously showed that the structural integrity of a glomerular endothelial glycocalyx is required to prevent albuminuria. Therefore we tested the potential of atrasentan to stabilize the endothelial glycocalyx in diabetic apolipoprotein E (apoE)-deficient mice in relation to its antialbuminuric effects. Treatment with atrasentan (7.5 mg/kg/day) for 4 weeks reduced urinary albumin-to-creatinine ratios by 26.0 ± 6.5% (P < 0.01) in apoE knockout (KO) mice with streptozotocin-induced diabetes consuming an atherogenic diet, without changes in gross glomerular morphology, systemic blood pressure, and blood glucose concentration. Endothelial cationic ferritin surface coverage, investigated using large-scale digital transmission electron microscopy, revealed that atrasentan treatment increases glycocalyx coverage in diabetic apoE KO mice from 40.7 ± 3.2% to 81.0 ± 12.5% (P < 0.05). This restoration is accompanied by increased renal nitric oxide concentrations, reduced expression of glomerular heparanase, and a marked shift in the balance of M1 and M2 glomerular macrophages. In vitro experiments with endothelial cells exposed to laminar flow and cocultured with pericytes confirmed that atrasentan reduced endothelial heparanase expression and increased glycocalyx thickness in the presence of a diabetic milieu. Together these data point toward a role for the restoration of endothelial function and tissue homeostasis through the antialbuminuric effects of atrasentan, and they provide a mechanistic explanation for the clinical observations of reduced albuminuria with atrasentan in diabetic nephropathy.

  9. Glomerular hemodynamic alterations during acute hyperinsulinemia in normal and diabetic rats

    Science.gov (United States)

    Tucker, B. J.; Anderson, C. M.; Thies, R. S.; Collins, R. C.; Blantz, R. C.

    1992-01-01

    Treatment of insulin dependent diabetes invariably requires exogenous insulin to control blood glucose. Insulin treatment, independent of other factors associated with insulin dependent diabetes, may induce changes that affect glomerular function. Due to exogenous delivery of insulin in insulin dependent diabetes entering systemic circulation prior to the portal vein, plasma levels of insulin are often in excess of that observed in non-diabetics. The specific effects of hyperinsulinemia on glomerular hemodynamics have not been previously examined. Micropuncture studies were performed in control (non-diabetic), untreated diabetic and insulin-treated diabetic rats 7 to 10 days after administration of 65 mg/kg body weight streptozotocin. After the first period micropuncture measurements were obtained, 5 U of regular insulin (Humulin-R) was infused i.v., and glucose clamped at euglycemic values (80 to 120 mg/dl). Blood glucose concentration in non-diabetic controls was 99 +/- 6 mg/dl. In control rats, insulin infusion and glucose clamp increased nephron filtration rate due to decreases in both afferent and efferent arteriolar resistance (afferent greater than efferent) resulting in increased plasma flow and increased glomerular hydrostatic pressure gradient. However, insulin infusion and glucose clamp produced the opposite effect in both untreated and insulin-treated diabetic rats with afferent arteriolar vasoconstriction resulting in decreases in plasma flow, glomerular hydrostatic pressure gradient and nephron filtration rate. Thromboxane A2 (TX) synthetase inhibition partially decreased the vasoconstrictive response due to acute insulin infusion in diabetic rats preventing the decrease in nephron filtration rate.(ABSTRACT TRUNCATED AT 250 WORDS).

  10. Radiation induced changes in the expression of fibronectin, Pai-1, MMP in rat glomerular epithelial cell

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    Park, Woo Yoon; Kim, Won Dong; Zheng, Ying; Ha, Tae Sun [Chungbuk National University, Cheongju (Korea, Republic of); Kim, Jae Sung [Seoul National University, Seoul (Korea, Republic of); Cho, Moon June [Chungnam National University, Daejeon (Korea, Republic of)

    2006-03-15

    Renal irradiation can lead to the development of radiation nephropathy, and this is characterized by the accumulation of extracellular matrix and final fibrosis. To determine the possible role of the glomerular epithelial cell, the radiation-induced changes in the expression of its genes associated with the extracellular matrix were analyzed. Rat glomerular epithelial cells (GEpC) were irradiated with a single dose of 0, 2, 5, 10 and 20 Gy with using 6 MV LINAC (Siemens, USA), and the samples were collected 6, 24, 48 and 72 hours post-irradiation, respectively. Northern blotting, western blotting and zymography were used to measure the expression level of fibronectin (Fn), plasminogen activator inhibitor-1 (Pai-1), matrix metalloproteinases-2, 9 (MMP-2, 9), tissue inhibitor of metalloproteinases-2 (TIMP-2), tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA). Irradiation with a single dose of 10 Gy resulted in a significant increase in Fn mRNA since 24 hours post-irradiation, and a single dose of 5 and 10 Gy significantly increased the Fn immunoreactive protein measured 48 hours post-irradiation. An increase in Pai-mRNA and protein was also observed and especially, a single dose of 10 Gy significantly increased the mRNA measured 24 and 48 hours post-irradiation. The active MMP-2 measured 24 hours post-irradiation slightly increased in a dose dependent manner, but this increase did not reach statistical significance. The levels of MMP-9, TIMP-2, t-PA and u-PA appeared unaltered after irradiation. Irradiation of the glomerular epithelial cells altered the expression of genes associated with the extracellular matrix, implying that the glomerular epithelial cell may be involved in the development of radiation nephropathy.

  11. PATTERN OF GLOMERULAR DISEASES IN PATIENTS WITH SIGNIFICANT PROTEINURIA: A CLINICOPATHOLOGICAL STUDY FROM UPPER ASSAM

    Directory of Open Access Journals (Sweden)

    Sawjib Borphukan

    2016-07-01

    Full Text Available BACKGROUND The prevalence of biopsy proven glomerular diseases varies according to the geographic area, race, age, demography and indication of renal biopsy. This has been poorly studied in the North-Eastern part of India, especially from Assam, the largest state, population-wise. METHODS This is a retrospective and observational study of kidney biopsy records and relevant clinical data of mainly adult patients. Patients (≥ 16 years old presenting with significant proteinuria (> 2 g/24 hours who attended our Medical College from October 2012 to September 2015 were subjected to kidney biopsy provided they were able to afford the cost and willing for the same. All biopsies were subjected to light and immunofluorescence microscopy. The histopathological pattern was analysed according to various clinical parameters. RESULTS A total of 136 kidney biopsies were included for analysis. 72 cases (52.9% were males and 64 (47.1% were females. Mean age of the patients was 37 ± 15.7 years. Among the patients, 85.3% (n = 116 were diagnosed with primary glomerular disease (PGD and 14.7% (n = 20 were diagnosed with secondary glomerular disease (SGD. The most common histopathological lesion was minimal change disease (MCD (27.9% followed by membranous glomerulonephritis or nephropathy (MGN (24.3%. In the age group ≥ 40 years, MGN (34.5% was the predominant histological lesion followed by MCD (20.7%. Lupus nephritis (LN (11% was the most common secondary glomerular pathology. 20 of our patients (14.70% had creatinine levels more than 1.5 mg/dL. CONCLUSION In this study, MCD was the commonest lesion in our north-east adult population in a wide age range. However, MGN was predominant in the middle age and elderly patients. This is in contrast to the trend in the increasing incidence of FSGS found in other parts of the country and western population.

  12. Elastase induces lung epithelial cell autophagy through placental growth factor

    Science.gov (United States)

    Hou, Hsin-Han; Cheng, Shih-Lung; Chung, Kuei-Pin; Kuo, Mark Yen-Ping; Yeh, Cheng-Chang; Chang, Bei-En; Lu, Hsuan-Hsuan; Wang, Hao-Chien; Yu, Chong-Jen

    2014-01-01

    Chronic obstructive pulmonary disease (COPD) is a devastating disease, which is associated with increasing mortality and morbidity. Therefore, there is a need to clearly define the COPD pathogenic mechanism and to explore effective therapies. Previous studies indicated that cigarette smoke (CS) induces autophagy and apoptosis in lung epithelial (LE) cells. Excessive ELANE/HNE (elastase, neutrophil elastase), a factor involved in protease-antiprotease imbalance and the pathogenesis of COPD, causes LE cell apoptosis and upregulates the expression of several stimulus-responsive genes. However, whether or not elastase induces autophagy in LE cell remains unknown. The level of PGF (placental growth factor) is higher in COPD patients than non-COPD controls. We hypothesize that elastase induces PGF expression and causes autophagy in LE cells. In this study, we demonstrated that porcine pancreatic elastase (PPE) induced PGF expression and secretion in LE cells in vitro and in vivo. The activation of MAPK8/JNK1 (mitogen-activated protein kinase 8) and MAPK14/p38alpha MAPK signaling pathways was involved in the PGF mediated regulation of the TSC (tuberous sclerosis complex) pathway and autophagy in LE cells. Notably, PGF-induced MAPK8 and MAPK14 signaling pathways mediated the inactivation of MTOR (mechanistic target of rapamycin), the upregulation of MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 β) and the increase of autophagosome formation in mice. Furthermore, the PPE-induced autophagy promotes further apoptosis in vitro and in vivo. In summary, elastase-induced autophagy promotes LE cell apoptosis and pulmonary emphysema through the upregulation of PGF. PGF and its downstream MAPK8 and MAPK14 signaling pathways are potential therapeutic targets for the treatment of emphysema and COPD. PMID:24988221

  13. Role of autophagy in COPD skeletal muscle dysfunction.

    Science.gov (United States)

    Hussain, Sabah N A; Sandri, Marco

    2013-05-01

    Chronic obstructive pulmonary disease (COPD) is a debilitating disease caused by parenchymal damage and irreversible airflow limitation. In addition to lung dysfunction, patients with COPD develop weight loss, malnutrition, poor exercise performance, and skeletal muscle atrophy. The latter has been attributed to an imbalance between muscle protein synthesis and protein degradation. Several reports have confirmed that enhanced protein degradation and atrophy of limb muscles of COPD patient is mediated in part through activation of the ubiquitin-proteasome pathway and that this activation is triggered by enhanced production of reactive oxygen species. Until recently, the importance of the autophagy-lysosome pathway in protein degradation of skeletal muscles has been largely ignored, however, recent evidence suggests that this pathway is actively involved in recycling of cytosolic proteins, organelles, and protein aggregates in normal skeletal muscles. The protective role of autophagy in the regulation of muscle mass has recently been uncovered in mice with muscle-specific suppression of autophagy. These mice develop severe muscle weakness, atrophy, and decreased muscle contractility. No information is yet available about the involvement of the autophagy in the regulation of skeletal muscle mass in COPD patients. Pilot experiments on vastus lateralis muscle samples suggest that the autophagy-lysosome system is induced in COPD patients compared with control subjects. In this review, we summarize recent progress related to molecular structure, regulation, and roles of the autophagy-lysosome pathway in normal and diseased skeletal muscles. We also speculate about regulation and functional importance of this system in skeletal muscle dysfunction in COPD patients.

  14. B cell autophagy mediates TLR7-dependent autoimmunity and inflammation.

    Science.gov (United States)

    Weindel, Chi G; Richey, Lauren J; Bolland, Silvia; Mehta, Abhiruchi J; Kearney, John F; Huber, Brigitte T

    2015-01-01

    Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease, defined by loss of B cell self-tolerance that results in production of antinuclear antibodies (ANA) and chronic inflammation. While the initiating events in lupus development are not well defined, overexpression of the RNA-recognizing toll-like receptor (TLR)7 has been linked to SLE in humans and mice. We postulated that autophagy plays an essential role in TLR7 activation of B cells for the induction of SLE by delivering RNA ligands to the endosomes, where this innate immune receptor resides. To test this hypothesis, we compared SLE development in Tlr7 transgenic (Tg) mice with or without B cell-specific ablation of autophagy (Cd19-Cre Atg5(f/f)). We observed that in the absence of B cell autophagy the 2 hallmarks of SLE, ANA and inflammation, were eliminated, thus curing these mice of lupus. This was also evident in the significantly extended survival of the autophagy-deficient mice compared to Tlr7.1 Tg mice. Furthermore, glomerulonephritis was ameliorated, and the serum levels of inflammatory cytokines in the knockout (KO) mice were indistinguishable from those of control mice. These data provide direct evidence that B cells require TLR7-dependent priming through an autophagy-dependent mechanism before autoimmunity is induced, thereafter involving many cell types. Surprisingly, hyper-IgM production persisted in Tlr7.1 Tg mice in the absence of autophagy, likely involving a different activation pathway than the production of autoantibodies. Furthermore, these mice still presented with anemia, but responded with a striking increase in extramedullary hematopoiesis (EMH), possibly due to the absence of pro-inflammatory cytokines.

  15. ARP101 inhibits α-MSH-stimulated melanogenesis by regulation of autophagy in melanocytes.

    Science.gov (United States)

    Kim, Eun Sung; Jo, Yoon Kyung; Park, So Jung; Chang, Huikyoung; Shin, Ji Hyun; Choi, Eun Sun; Kim, Jun Bum; Seok, Su Hyeon; Kim, Jae-Sung; Oh, Jeong Su; Kim, Myoung-Hwan; Lee, Eunjoo H; Cho, Dong-Hyung

    2013-12-11

    Autophagy is a cooperative process between autophagosomes and lysosomes that degrades cellular organelles. Although autophagy regulates the turnover of cellular components, its role in melanogenesis is not clearly established. Previously, we reported that ARP101 induces autophagy in various cancer cells. Here, we show that ARP101 inhibits melanogenesis by regulation of autophagy. ARP101 inhibited α-MSH-stimulated melanin synthesis and suppressed the expression of tyrosinase and TRP1 in immortalized mouse melanocytes. ARP101 also induced autophagy in melanocytes. Knockdown of ATG5 reduced both anti-melanogenic activity and autophagy mediated by ARP101 in α-MSH treated melanocytes. Electron microscopy analysis further revealed that autophagosomes engulf melanin or melanosome in α-MSH and ARP101-treated cells. Collectively, our results suggest that ARP101 inhibits α-MSH-stimulated melanogenesis through the activation of autophagy in melanocytes.

  16. Induction of Autophagy by Second-Fermentation Yeasts during Elaboration of Sparkling Wines

    Science.gov (United States)

    Cebollero, Eduardo; Gonzalez, Ramon

    2006-01-01

    Autophagy is a transport system mediated by vesicles, ubiquitous in eukaryotic cells, by which bulk cytoplasm is targeted to a lysosome or vacuole for degradation. In the yeast Saccharomyces cerevisiae, autophagy is triggered by nutritional stress conditions (e.g., carbon- or nitrogen-depleted medium). In this study we showed that there is induction of autophagy in second-fermentation yeasts during sparkling wine making. Two methods were employed to detect autophagy: a biochemical approach based on depletion of the protein acetaldehyde dehydrogenase Ald6p and a morphological strategy consisting of visualization of autophagic bodies and autophagosomes, which are intermediate vesicles in the autophagic process, by transmission electron microscopy. This study provides the first demonstration of autophagy in second-fermentation yeasts under enological conditions. The correlation between autophagy and yeast autolysis during sparkling wine production is discussed, and genetic engineering of autophagy-related genes in order to accelerate the aging steps in wine making is proposed. PMID:16751523

  17. Autophagy activation aggravates neuronal injury in the hippocampus of vascular dementia rats

    Institute of Scientific and Technical Information of China (English)

    Bin Liu; Jing Tang; Jinxia Zhang; Shiying Li; Min Yuan; Ruimin Wang

    2014-01-01

    It remains unclear whether autophagy affects hippocampal neuronal injury in vascular dementia. In the present study, we investigated the effects of autophagy blockade on hippocampal neuro-nal injury in a rat model of vascular dementia. In model rats, hippocampal CA1 neurons were severely damaged, and expression of the autophagy-related proteins beclin-1, cathepsin B and microtubule-associated protein 1 light chain 3 was elevated compared with that in sham-oper-ated animals. These responses were suppressed in animals that received a single intraperitoneal injection of wortmannin, an autophagy inhibitor, prior to model establishment. The present results conifrm that autophagy and autophagy-related proteins are involved in the pathological changes of vascular dementia, and that inhibition of autophagy has neuroprotective effects.

  18. Rph1 mediates the nutrient-limitation signaling pathway leading to transcriptional activation of autophagy.

    Science.gov (United States)

    Bernard, Amélie; Klionsky, Daniel J

    2015-04-01

    To maintain proper cellular homeostasis, the magnitude of autophagy activity has to be finely tuned in response to environmental changes. Many aspects of autophagy regulation have been extensively studied: pathways integrating signals through the master regulators TORC1 and PKA lead to multiple post-translational modifications affecting the functions, protein-protein interactions, and localization of Atg proteins. The expression of several ATG genes increases sharply upon autophagy induction conditions, and defects in ATG gene expression are associated with various diseases, pointing to the importance of transcriptional regulation of autophagy. Yet, how changes in ATG gene expression affect the rate of autophagy is not well characterized, and transcriptional regulators of the autophagy pathway remain largely unknown. To identify such regulators, we analyzed the expression of several ATG genes in a library of DNA-binding protein mutants. This led to the identification of Rph1 as a master transcriptional regulator of autophagy.

  19. Plant autophagy puts the brakes on cell death by controlling salicylic acid signaling.

    Science.gov (United States)

    Yoshimoto, Kohki

    2010-01-01

    It has long been recognized that autophagy in plants is important for nutrient recycling and plays a critical role in the ability of plants to adapt to environmental extremes such as nutrient deprivation. Recent reverse genetic studies, however, hint at other roles for autophagy, showing that autophagy defects in higher plants result in early senescence and excessive immunity-related programmed cell death (PCD), irrespective of nutrient conditions. Until now, the mechanisms by which cells die in the absence of autophagy were unclear. In our study, using biochemical, pharmacological and genetic approaches, we reveal that excessive salicylic acid (SA) signaling is a major factor in autophagy-defective plant-dependent cell death and that the SA signal can induce autophagy. These findings suggest a novel physiological function for plant autophagy that operates via a negative feedback loop to modulate proper SA signaling.

  20. Nuclear autophagy: An evolutionarily conserved mechanism of nuclear degradation in the cytoplasm.

    Science.gov (United States)

    Luo, Majing; Zhao, Xueya; Song, Ying; Cheng, Hanhua; Zhou, Rongjia

    2016-11-01

    Macroautophagy/autophagy is a catabolic process that is essential for cellular homeostasis. Studies on autophagic degradation of cytoplasmic components have generated interest in nuclear autophagy. Although its mechanisms and roles have remained elusive, tremendous progress has been made toward understanding nuclear autophagy. Nuclear autophagy is evolutionarily conserved in eukaryotes that may target various nuclear components through a series of processes, including nuclear sensing, nuclear export, autophagic substrate encapsulation and autophagic degradation in the cytoplasm. However, the molecular processes and regulatory mechanisms involved in nuclear autophagy remain largely unknown. Numerous studies have highlighted the importance of nuclear autophagy in physiological and pathological processes such as cancer. This review focuses on current advances in nuclear autophagy and provides a summary of its research history and landmark discoveries to offer new perspectives.

  1. Role of alpha-synuclein in autophagy modulation of primary human T lymphocytes.

    Science.gov (United States)

    Colasanti, T; Vomero, M; Alessandri, C; Barbati, C; Maselli, A; Camperio, C; Conti, F; Tinari, A; Carlo-Stella, C; Tuosto, L; Benincasa, D; Valesini, G; Malorni, W; Pierdominici, M; Ortona, E

    2014-05-29

    It has been demonstrated that α-synuclein can aggregate and contribute to the pathogenesis of some neurodegenerative diseases and it is capable of hindering autophagy in neuronal cells. Here, we investigated the implication of α-synuclein in the autophagy process in primary human T lymphocytes. We provide evidence that: (i) knocking down of the α-synuclein gene resulted in increased autophagy, (ii) autophagy induction by energy deprivation was associated with a significant decrease of α-synuclein levels, (iii) autophagy inhibition by 3-methyladenine or by ATG5 knocking down led to a significant increase of α-synuclein levels, and (iv) autophagy impairment, constitutive in T lymphocytes from patients with systemic lupus erythematosus, was associated with abnormal accumulation of α-synuclein aggregates. These results suggest that α-synuclein could be considered as an autophagy-related marker of peripheral blood lymphocytes, potentially suitable for use in the clinical practice.

  2. Glomerular filtration rate is altered in children with sickle cell disease: a comparison between Hb SS and Hb SC

    Science.gov (United States)

    de Paula, Rafael Pereira; Nascimento, Alana Ferreira; Sousa, Sandra Mara Bispo; Bastos, Paulo Roberto Velasco; Barbosa, Ana Angélica Leal

    2013-01-01

    Background Renal failure is common among older patients with sickle cell disease; this is preceded by subclinical glomerular hyperfiltration. Data about renal function of adults with sickle cell disease have been reported, but data on children is scarce, especially when comparing heterozygotic and homozygotic patients. Objective The goal of this study was to investigate the glomerular filtration rate of heterozygotic and homozygotic children with sickle cell disease. Methods The glomerular filtration rate of 11 children with sickle cell disease [7 homozygotic (SS) and 4 heterozygotic (SC)] with a mean age of 11 years (standard deviation: ± 5 years) was evaluated using standard laboratory techniques. Results are presented as descriptive analysis. Results Our results suggest that glomerular hyperfiltration is present in children with sickle cell disease; this is more evident in homozygotic than heterozygotic children. Conclusion There is evidence of a need to monitor the renal function of children with sickle cell disease when special attention should be paid to homozygotic patients. PMID:24255619

  3. Measurement of glomerular filtration rate by impulse synthesis: Clinical validation and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Palagi, B.; Verga, P.; Broggi, A.; Picozzi, R.; Villa, F.; Guzzini, F.; Cozzi, C.; Tomasi, A.

    1988-08-01

    Impulse synthesis is a technique which relies upon the logic of continuous infusion but extracts the clearance value from single-injection data by shifting and adding them until an asymptotic value is attained. This study has been aimed at validating and optimizing clinically the measurement of glomerular filtration rate by impulse synthesis. A single intravenous injection of /sup 51/Cr-EDTA has been made in 32 patients and plasma activity monitored over the next 6 h. Glomerular filtration rate computed by a single-exponential fit method (GFR-SEF) has been shown to be significantly (p<0.001) overestimated when compared with the glomerular filtration rate obtained by the impulse synthesis technique (GFR-IS) in spite of an excellent (r=0.989) linear correlation between the two sets of data. On the other hand, the comparison between GFR-IS and 24-h creatinine clearance has not shown any significant difference. Moreover, we have found that in patients with severe renal failure GFR-IS is overestimated when the sampling time span is shortened to 3 h. On the other hand, GFR-IS is slightly underestimated in patients with severe renal failure when the convolution time interval is increased over a few minutes.

  4. Autoantibodies targeting glomerular annexin A2 identify patients with proliferative lupus nephritis

    Science.gov (United States)

    Caster, Dawn J.; Korte, Erik A.; Merchant, Michael L.; Klein, Jon B.; Wilkey, Daniel W.; Rovin, Brad H.; Birmingham, Dan J.; Harley, John B.; Cobb, Beth L.; Namjou, Bahram; McLeish, Kenneth R.; Powell, David W.

    2015-01-01

    PURPOSE Patients with systemic lupus erythematosus (SLE) frequently develop lupus nephritis (LN), a complication frequently leading to end stage kidney disease. Immune complex deposition in the glomerulus is central to the development of LN. Using a targeted proteomic approach, we tested the hypothesis that autoantibodies targeting glomerular antigens contribute to the development of LN. EXPERIMENTAL DESIGN Human podocyte and glomerular proteins were separated by SDS-PAGE and immunoblotted with sera from SLE patients with and without LN. The regions of those gels corresponding to reactive bands observed with sera from LN patients were analyzed using LC-MS/MS. RESULTS LN reactive bands were seen at approximately 50 kDa in podocyte extracts and between 36-50 kDa in glomerular extracts. Those bands were analyzed by LC-MS/MS and 102 overlapping proteins were identified. Bioinformatic analysis determined that 36 of those proteins were membrane associated, including a protein previously suggested to contribute to glomerulonephritis and LN, annexin A2. By ELISA, patients with proliferative LN demonstrated significantly increased antibodies against annexin A2. CONCLUSION AND CLINICAL RELEVANCE Proteomic approaches identified multiple candidate antigens for autoantibodies in patients with LN. Serum antibodies against annexin A2 were significantly elevated in subjects with proliferative LN, validating those antibodies as potential biomarkers. PMID:25824007

  5. Involvement of MAPKs in ICAM-1 Expression in Glomerular Endothelial Cells in Diabetic Nephropathy

    Directory of Open Access Journals (Sweden)

    Watanabe,Naomi

    2011-08-01

    Full Text Available Inflammatory processes are involved in the pathogenesis of diabetic nephropathy. The aim of this study was to clarify the role of mitogen-activated protein kinase (MAPK pathways for induction of intercellular adhesion molecule-1 (ICAM-1 expression in glomerular endothelial cells under diabetic conditions. We examined the expression of ICAM-1 in the kidneys of experimental diabetic rats. Human glomerular endothelial cells (GE cells were exposed to normal glucose concentration, high glucose concentration (HG, or high mannitol concentration (HM, and then the expression of the ICAM-1 protein and the phosphorylation of the 3 subfamilies of mitogen-activated protein kinase (MAPK were determined using Western blot analysis. Next, to evaluate the involvement of MAPKs in HG- or HM-induced ICAM-1 expression, we preincubated GE cells with the inhibitors for ERK, p38 or JNK 1h prior to the application of glucose or mannitol. Expression of ICAM-1 was increased in the glomeruli of diabetic rats. Both HG and HM induced ICAM-1 expression and phosphorylation of ERK1/2, p38 and JNK in GE cells. Expression of ICAM-1 was significantly attenuated by inhibitors of ERK, p38 and JNK. We conclude that activation of ERK1/2, p38 and JNK cascades may be involved in ICAM-1 expression in glomerular endothelial cells under diabetic conditions.

  6. Darbepoetin-α treatment enhances glomerular regenerative process in the Thy-1 glomerulonephritis model.

    Science.gov (United States)

    Cañadillas, Sagrario; Ortega, Rosa; Estepa, Jose-Carlos; Egea, Jeronimo; Gonzalez-Menchen, Alberto; Perez-Seoane, Carlos; Lopez-Andreu, Maria; Ramirez, Rafael; Tetta, Ciro; Rodriguez, Mariano; Martin-Malo, Alejandro; Aljama, Pedro

    2010-12-01

    Recent studies have demonstrated that erythropoietin (EPO) and its analogs induce cytoprotective effects on many nonerythroid cells. In this study, we examined whether darbepoetin-α might prevent glomerular lesions in the Thy-1.1 model of glomerulonephritis (Thy-1-GN). GN was induced in Wistar rats by a single injection of monoclonal anti-Thy-1.1 antibody. Rats were killed at 24 h, 72 h, 7 days, 10 days, or 15 days after antibody injection. Kidneys were removed for histological analysis, and proteinuria was measured. Because at day 7 the maximal degree of renal damage and proteinuria was found, the effect of darbepoetin-α was tested at day 7 and two different protocols of administration were used; After anti-Thy-1.1 injection, rats received two doses of darbepoetin-α or vehicle at days 0 and 4 or at days 4 and 6. At day 7, proteinuria, plasma creatinine concentration, and renal morphology analysis were performed. Also, α-actin, desmin, caspase-3, and Ki67 protein expression were evaluated by immunohistochemistry. Our results showed that in both protocols of administration, darbepoetin-α treatment decreased proteinuria in Thy-1-GN rats and this effect correlated with the improvement in renal morphology. Glomerular lesions, α-actin, and caspase-3 protein expression, observed in most glomeruli of Thy-1-GN rats, were significantly reduced in darbepoetin-α-treated rats, while cell proliferation was significantly enhanced. The results indicate that darbepoetin-α treatment promotes glomerular recovery.

  7. Intrarenal renin-angiotensin system modulates glomerular angiotensin receptors in the rat

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    Wilkes, B.M.; Pion, I.; Sollott, S.; Michaels, S.; Kiesel, G. (North Shore Univ. Hospital and Cornell Univ. Medical College, Manhasset, NY (USA))

    1988-03-01

    The aim of this study was to test the hypothesis that the intrarenal renin-angiotensin system (RAS) modulates glomerular angiotensin II (ANG II) receptors. In one protocol ANG II receptors were measured 7 days after unilateral denervation of the left kidney in rats. There were 50% more receptors in the glomeruli from denervated compared with innervated kidneys, which was associated with a 63% reduction in left renal vein renin. The differences in ANG II receptors between the left and right kidneys were not longer present when angiotensin-converting enzyme was inhibited with enalapril or when pharmacological amounts of ANG II were infused. In a second protocol, renal cortical renin content was raised in the left kidney by placing a 0.20-mm clip on the left renal artery. At 7 days, glomerular ANG II receptors were reduced by 72.3% in the clipped compared with the contralateral kidneys. The differences in ANG II receptors were no longer present after enalapril treatment. Pharmacological maneuvers that either blocked ANG II formation or increased circulating ANG II resulted in an equal number of ANG II receptors in the right and left kidneys. The data indicate that the intrarenal RAS modulates the density of glomerular ANG II receptors and is a more important receptor modulation than plasma ANG II.

  8. The Macrophage Is a Key Factor in Renal Injuries Caused by Glomerular Hyperfiltration

    Directory of Open Access Journals (Sweden)

    Sasaki,Motofumi

    2011-04-01

    Full Text Available Glomerular hyperfiltration is a common pathway leading to glomerulosclerosis in various kinds of kidney diseases. The 5/6 renal ablation is an established experimental animal model for glomerular hyperfiltration. On the other hand, low-grade inflammation is also a common mechanism for the progression of kidney diseases including diabetic nephropathy and atherosclerosis. Here we analyzed the gene expression profile in the remnant kidney tissues of 5/6 nephrectomized mice using a DNA microarray system and compared it with that of sham-operated control mice. The 5/6 nephrectomized mice showed glomerular hypertrophy and an increase in the extracellular matrix in the glomeruli. DNA microarray analysis indicated the up-regulated expression of various kinds of genes related to the inflammatory process in remnant kidneys. We confirmed the up-regulated expression of platelet factor-4, and monocyte chemoattractant protein-1, 2, and 5 in remnant kidneys by RT-PCR. The current results suggest that the inflammatory process is involved in the progression of glomerulosclerosis and is a common pathway of the pathogenesis of kidney disease.

  9. microRNA-101 is a potent inhibitor of autophagy

    DEFF Research Database (Denmark)

    Frankel, Lisa B; Wen, Jiayu; Lees, Michael

    2011-01-01

    performed a functional screen in search of microRNAs (miRNAs), which regulate the autophagic flux in breast cancer cells. In this study, we identified the tumour suppressive miRNA, miR-101, as a potent inhibitor of basal, etoposide- and rapamycin-induced autophagy. Through transcriptome profiling, we...... identified three novel miR-101 targets, STMN1, RAB5A and ATG4D. siRNA-mediated depletion of these genes phenocopied the effect of miR-101 overexpression, demonstrating their importance in autophagy regulation. Importantly, overexpression of STMN1 could partially rescue cells from miR-101-mediated inhibition...

  10. Salvianolic acid B inhibits autophagy and protects starving cardiac myocytes

    OpenAIRE

    Han, Xiao; Liu, Jian-Xun; Xin-zhi LI

    2010-01-01

    Aim: To investigate the protective or lethal role of autophagy and the effects of Salvianolic acid B (Sal B) on autophagy in starving myocytes. Methods: Cardiac myocytes were incubated under starvation conditions (GD) for 0, 1, 2, 3, and 6 h. Autophagic flux in starving cells was measured via chloroquine (3 μmol/L). After myocytes were treated with Sal B (50 μmol/L) in the presence or absence of chloroquine (3 μmol/L) under GD 3 h, the amount of LC3-II, the abundance of LC3-positive fluoresce...

  11. Viruses, Autophagy Genes, and Crohn’s Disease

    Directory of Open Access Journals (Sweden)

    Vanessa M. Hubbard

    2011-07-01

    Full Text Available The etiology of the intestinal disease Crohn’s disease involves genetic factors as well as ill-defined environmental agents. Several genetic variants linked to this disease are associated with autophagy, a process that is critical for proper responses to viral infections. While a role for viruses in this disease remains speculative, accumulating evidence indicate that this possibility requires serious consideration. In this review, we will examine the three-way relationship between viruses, autophagy genes, and Crohn’s disease and discuss how host-pathogen interactions can mediate complex inflammatory disorders.

  12. The lack of autophagy triggers precocious activation of Notch signaling during Drosophila oogenesis

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    Barth Julia MI

    2012-12-01

    Full Text Available Abstract Background The proper balance of autophagy, a lysosome-mediated degradation process, is indispensable for oogenesis in Drosophila. We recently demonstrated that egg development depends on autophagy in the somatic follicle cells (FC, but not in the germline cells (GCs. However, the lack of autophagy only affects oogenesis when FCs are autophagy-deficient but GCs are wild type, indicating that a dysfunctional signaling between soma and germline may be responsible for the oogenesis defects. Thus, autophagy could play an essential role in modulating signal transduction pathways during egg development. Results Here, we provide further evidence for the necessity of autophagy during oogenesis and demonstrate that autophagy is especially required in subsets of FCs. Generation of autophagy-deficient FCs leads to a wide range of phenotypes that are similar to mutants with defects in the classical cell-cell signaling pathways in the ovary. Interestingly, we observe that loss of autophagy leads to a precocious activation of the Notch pathway in the FCs as monitored by the expression of Cut and Hindsight, two downstream effectors of Notch signaling. Conclusion Our findings point to an unexpected function for autophagy in the modulation of the Notch signaling pathway during Drosophila oogenesis and suggest a function for autophagy in proper receptor activation. Egg development is affected by an imbalance of autophagy between signal sending (germline and signal receiving cell (FC, thus the lack of autophagy in the germline is likely to decrease the amount of active ligand and accordingly compensates for increased signaling in autophagy-defective follicle cells.

  13. Prohibitin 1 modulates mitochondrial stress-related autophagy in human colonic epithelial cells.

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    Arwa S Kathiria

    Full Text Available INTRODUCTION: Autophagy is an adaptive response to extracellular and intracellular stress by which cytoplasmic components and organelles, including damaged mitochondria, are degraded to promote cell survival and restore cell homeostasis. Certain genes involved in autophagy confer susceptibility to Crohn's disease. Reactive oxygen species and pro-inflammatory cytokines such as tumor necrosis factor α (TNFα, both of which are increased during active inflammatory bowel disease, promote cellular injury and autophagy via mitochondrial damage. Prohibitin (PHB, which plays a role in maintaining normal mitochondrial respiratory function, is decreased during active inflammatory bowel disease. Restoration of colonic epithelial PHB expression protects mice from experimental colitis and combats oxidative stress. In this study, we investigated the potential role of PHB in modulating mitochondrial stress-related autophagy in intestinal epithelial cells. METHODS: We measured autophagy activation in response to knockdown of PHB expression by RNA interference in Caco2-BBE and HCT116 WT and p53 null cells. The effect of exogenous PHB expression on TNFα- and IFNγ-induced autophagy was assessed. Autophagy was inhibited using Bafilomycin A(1 or siATG16L1 during PHB knockdown and the affect on intracellular oxidative stress, mitochondrial membrane potential, and cell viability were determined. The requirement of intracellular ROS in siPHB-induced autophagy was assessed using the ROS scavenger N-acetyl-L-cysteine. RESULTS: TNFα and IFNγ-induced autophagy inversely correlated with PHB protein expression. Exogenous PHB expression reduced basal autophagy and TNFα-induced autophagy. Gene silencing of PHB in epithelial cells induces mitochondrial autophagy via increased intracellular ROS. Inhibition of autophagy during PHB knockdown exacerbates mitochondrial depolarization and reduces cell viability. CONCLUSIONS: Decreased PHB levels coupled with dysfunctional

  14. A dual role of p53 in the control of autophagy.

    Science.gov (United States)

    Tasdemir, Ezgi; Chiara Maiuri, M; Morselli, Eugenia; Criollo, Alfredo; D'Amelio, Marcello; Djavaheri-Mergny, Mojgan; Cecconi, Francesco; Tavernarakis, Nektarios; Kroemer, Guido

    2008-08-01

    Genotoxic stress can induce autophagy in a p53-dependent fashion and p53 can transactivate autophagy-inducing genes. We have observed recently that inactivation of p53 by deletion, depletion or inhibition can trigger autophagy. Thus, human and mouse cells subjected to knockout, knockdown or pharmacological inhibition of p53 manifest signs of autophagy such as depletion of p62/SQSTM1, LC3 lipidation, redistribution of GFP-LC3 in cytoplasmic puncta, and accumulation of autophagosomes and autolysosomes, both in vitro and in vivo. Inhibition of p53 causes autophagy in enucleated cells, indicating that the cytoplasmic, non-nuclear pool of p53 can regulate autophagy. Accordingly, retransfection of p53(-/-) cells with wild-type p53 as well as a p53 mutant that is excluded from the nucleus (due to the deletion of the nuclear localization sequence) can inhibit autophagy, whereas retransfection with a nucleus-restricted p53 mutant (in which the nuclear localization sequence has been deleted) does not inhibit autophagy. Several distinct autophagy inducers (e.g., starvation, rapamycin, lithium, tunicamycin and thapsigargin) stimulate the rapid degradation of p53. In these conditions, inhibition of the p53-specific E3 ubiquitin ligase HDM2 can avoid p53 depletion and simultaneously prevent the activation of autophagy. Moreover, a p53 mutant that lacks the HDM2 ubiquitinylation site and hence is more stable than wild-type p53 is particularly efficient in suppressing autophagy. In conclusion, p53 plays a dual role in the control of autophagy. On the one hand, nuclear p53 can induce autophagy through transcriptional effects. On the other hand, cytoplasmic p53 may act as a master repressor of autophagy.

  15. Glomerular filtration rate estimated from the uptake phase of 99mTc-DTPA renography in chronic renal failure

    DEFF Research Database (Denmark)

    Petersen, L J; Petersen, J R; Talleruphuus, U

    1999-01-01

    The purpose of the study was to compare the estimation of glomerular filtration rate (GFR) from 99mTc-DTPA renography with that estimated from the renal clearance of 51Cr-EDTA, creatinine and urea.......The purpose of the study was to compare the estimation of glomerular filtration rate (GFR) from 99mTc-DTPA renography with that estimated from the renal clearance of 51Cr-EDTA, creatinine and urea....

  16. Glomerulo-tubular junction stenosis as a factor contributing to glomerular obsolescence in IgA nephropathy.

    Science.gov (United States)

    Sato, Mitsuhiro; Hotta, Osamu; Taguma, Yoshio

    2002-05-01

    Periglomerular fibrosis (PF) is an interstitial injury observed in various renal diseases. It is speculated that this lesion, by occluding the glomerulo-tubular junction (GTJ) and causing atubular glomeruli, may result functionally in a reduction of the glomerular filtration rate (GFR) and may be a factor contributing to the progression of renal disease. In the present study, 340 renal biopsy specimens were analysed to determine whether or not there was nephron injury derived from such a mechanism, as well as direct glomerular injury, in IgA nephropathy (IgAN). The patients were divided into five groups according to the degree of glomerular sclerosis. The average age was lower in groups with milder sclerosis and serum creatinine (Cr) was elevated in groups with more severe sclerosis. Because the GTJ was assumed to disappear when an atubular glomerulus was formed, the ratio of the number of glomeruli with discernible GTJ to the total number of glomeruli was evaluated. As glomerular sclerosis progressed, discernible GTJ reduced significantly (p <0.001) and the degree of PF increased significantly (p <0.05). By serial section study in cases with pronounced PF, transitions between the stages of stenosis of the GTJ and atubular glomeruli were observed. It is speculated that the occlusion of the GTJ eventually hyalinizes the glomerulus; in such cases, glomerular obsolescence of the collapse type might be formed. On the other hand, obsolescence of the mesangial proliferative type might be formed in the hyalinization derived from direct glomerular injury. In this context, glomerular obsolescence of the collapse type was observed more frequently and was accompanied by more increased PF than obsolescence of the mesangial proliferative type (p <0.001). These results suggest that in addition to direct glomerular injury, nephron injury derived from interstitial damage of this type plays an important contributory role in the progression of IgAN.

  17. Autophagy and SQSTM1 on the RHOA(d) again: emerging roles of autophagy in the degradation of signaling proteins.

    Science.gov (United States)

    Belaid, Amine; Ndiaye, Papa Diogop; Cerezo, Michaël; Cailleteau, Laurence; Brest, Patrick; Klionsky, Daniel J; Carle, Georges F; Hofman, Paul; Mograbi, Baharia

    2014-02-01

    Degradation of signaling proteins is one of the most powerful tumor-suppressive mechanisms by which a cell can control its own growth, its survival, and its motility. Emerging evidence suggests that autophagy limits several signaling pathways by degrading kinases, downstream components, and transcription factors; however, this often occurs under stressful conditions. Our recent studies revealed that constitutive autophagy temporally and spatially controls the RHOA pathway. Specifically, inhibition of autophagosome degradation induces the accumulation of the GTP-bound form of RHOA. The active RHOA is sequestered via SQSTM1/p62 within autolysosomes, and accordingly fails to localize to the spindle midbody or to the cell surface, as we demonstrate herein. As a result, all RHOA-downstream responses are deregulated, thus driving cytokinesis failure, aneuploidy and motility, three processes that directly have an impact upon cancer progression. We therefore propose that autophagy acts as a degradative brake for RHOA signaling and thereby controls cell proliferation, migration, and genome stability.

  18. Anti-glomerular basement membrane disease superimposed on membranous nephropathy: a case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Nivera Noel

    2010-08-01

    Full Text Available Abstract Introduction Anti-glomerular basement membrane disease is a rare autoimmune disorder characterized by pulmonary hemorrhage, crescentic glomerulonephritis and the presence of circulating anti-glomerular basement membrane antibodies. The simultaneous occurrence of both anti-glomerular basement membrane disease and membranous nephropathy is rare. Case presentation A 59-year-old Hispanic man presented with acute onset of nausea and vomiting and was found to have renal insufficiency. Work-up included a kidney biopsy, which revealed anti-glomerular basement membrane disease with underlying membranous nephropathy. He was treated with emergent hemodialysis, intravenous corticosteroids, plasmapheresis, and cyclophosphamide without improvement in his renal function. Conclusion Simultaneous anti-glomerular basement membrane disease and membranous nephropathy is very rare. There have been 16 previous case reports in the English language literature that have been associated with a high mortality and morbidity, and a very high rate of renal failure resulting in hemodialysis. Co-existence of membranous nephropathy and anti-glomerular basement membrane disease may be immune-mediated, although the exact mechanism is not clear.

  19. Assessing glomerular filtration rate in healthy adult potential kidney donors in Bangladesh: a comparison of various prediction equations with measured glomerular filtration rate by diethylentriamine pentaacetic acid renogram.