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Sample records for autophagy influences glomerular

  1. Cordyceps militaris improves the survival of Dahl salt-sensitive hypertensive rats possibly via influences of mitochondria and autophagy functions.

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    Takakura, Kentaro; Ito, Shogo; Sonoda, Junya; Tabata, Koji; Shiozaki, Motoko; Nagai, Kaoru; Shibata, Masahiro; Koike, Masato; Uchiyama, Yasuo; Gotow, Takahiro

    2017-11-01

    The genus Cordyceps and its specific ingredient, cordycepin, have attracted much attention for multiple health benefits and expectations for lifespan extension. We analyzed whether Cordyceps militaris (CM), which contains large amounts of cordycepin, can extend the survival of Dahl salt-sensitive rats, whose survival was reduced to ∼3 months via a high-salt diet. The survival of these life-shortened rats was extended significantly when supplemented with CM, possibly due to a minimization of the effects of stroke. Next, we analyzed the effect of CM on hypertension-sensitive organs, the central nervous systems (CNS), heart, kidney and liver of these rats. We attempted to ascertain how the organs were improved by CM, and we paid particular attention to mitochondria and autophagy functions. The following results were from CM-treated rats in comparison with control rats. Microscopically, CNS neurons, cardiomyocytes, glomerular podocytes, renal epithelial cells, and hepatocytes all were improved. However, immunoblot and immunohistochemical analysis showed that the expressions of mitochondria-related proteins, ATP synthase β subunit, SIRT3 and SOD2, and autophagy-related proteins, LC3-II/LC3-I ratio and cathepsin D all were reduced significantly in the CNS neurons, but increased significantly in the cells of the other three organs, although p62 was decreased in its expression in all the organs tested. Activity of Akt and mTOR was enhanced but that of AMPK was reduced in the CNS, while such kinase activity was completely the opposite in the other organs. Together, the influence of CM may differ between mitochondria and autophagy functioned between the two organ groups, as mitochondria and autophagy seemed to be repressed and promoted, respectively, in the CNS, while both mitochondria and autophagy were activated in the others. This could possibly be related to the steady or improved cellular activity in both the organs, which might result in the life extension of these

  2. Rheological Influence Upon the Glomerular Podocyte and Resultant Mechanotransduction

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    Simona Pichler Sekulic

    2015-03-01

    Full Text Available The glomerular podocyte is exposed to numerous mechanical forces as a constituent of the glomerular filtration apparatus. This includes fluid shear stress (FSS displaced upon the podocytic foot process's apical, lateral, and basal surfaces. Even in the face of continuous flow the podocyte is capable of contributing to physiologic filtration, however with pathologic levels of hyperfiltration there is increased FSS placed upon the cell. The mechanisms by which the podocyte detects and responds to FSS are topics of recent investigations, with the aim to clarify the way these cells are injured and/or adapt in times of hyperfiltration and disease states. As the pathogenesis of numerous glomerulopathies is contingent on the status of the podocyte, understanding the manner that these cells can be modified by FSS is essential. Likewise, determination of the effect of such mechanical forces upon other resident cells of the renal corpuscle would reveal the contribution of FSS in the progression of glomerular diseases. The biochemical manner in which podocytes sense and respond to FSS, that is mechanotransduction, will be discussed.

  3. Influencing factors of Gate's method to measure of glomerular filtration rate

    International Nuclear Information System (INIS)

    Wu Ha; Shi Hongcheng

    2009-01-01

    Glomerular filtration rate (GFR) is an important criterion to estimate renal function. 99 Tc m - diethylenetrimainepentaacetic acid renal dynamic imaging is one of method to measure GFR that it have the characteristics of simple and accurate. But the Gate's method may be influenced by many factors such as dose of imaging agent, outlined of regions of interest, kidney depth, and so on. (authors)

  4. Cordyceps militaris improves the survival of Dahl salt-sensitive hypertensive rats possibly via influences of mitochondria and autophagy functions

    Directory of Open Access Journals (Sweden)

    Kentaro Takakura

    2017-11-01

    Full Text Available The genus Cordyceps and its specific ingredient, cordycepin, have attracted much attention for multiple health benefits and expectations for lifespan extension. We analyzed whether Cordyceps militaris (CM, which contains large amounts of cordycepin, can extend the survival of Dahl salt-sensitive rats, whose survival was reduced to ∼3 months via a high-salt diet. The survival of these life-shortened rats was extended significantly when supplemented with CM, possibly due to a minimization of the effects of stroke. Next, we analyzed the effect of CM on hypertension-sensitive organs, the central nervous systems (CNS, heart, kidney and liver of these rats. We attempted to ascertain how the organs were improved by CM, and we paid particular attention to mitochondria and autophagy functions. The following results were from CM-treated rats in comparison with control rats. Microscopically, CNS neurons, cardiomyocytes, glomerular podocytes, renal epithelial cells, and hepatocytes all were improved. However, immunoblot and immunohistochemical analysis showed that the expressions of mitochondria-related proteins, ATP synthase β subunit, SIRT3 and SOD2, and autophagy-related proteins, LC3-II/LC3-I ratio and cathepsin D all were reduced significantly in the CNS neurons, but increased significantly in the cells of the other three organs, although p62 was decreased in its expression in all the organs tested. Activity of Akt and mTOR was enhanced but that of AMPK was reduced in the CNS, while such kinase activity was completely the opposite in the other organs. Together, the influence of CM may differ between mitochondria and autophagy functioned between the two organ groups, as mitochondria and autophagy seemed to be repressed and promoted, respectively, in the CNS, while both mitochondria and autophagy were activated in the others. This could possibly be related to the steady or improved cellular activity in both the organs, which might result in the

  5. 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

  6. Chloroplast Protein Turnover: The Influence of Extraplastidic Processes, Including Autophagy

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    Masanori Izumi

    2018-03-01

    Full Text Available Most assimilated nutrients in the leaves of land plants are stored in chloroplasts as photosynthetic proteins, where they mediate CO2 assimilation during growth. During senescence or under suboptimal conditions, chloroplast proteins are degraded, and the amino acids released during this process are used to produce young tissues, seeds, or respiratory energy. Protein degradation machineries contribute to the quality control of chloroplasts by removing damaged proteins caused by excess energy from sunlight. Whereas previous studies revealed that chloroplasts contain several types of intraplastidic proteases that likely derived from an endosymbiosed prokaryotic ancestor of chloroplasts, recent reports have demonstrated that multiple extraplastidic pathways also contribute to chloroplast protein turnover in response to specific cues. One such pathway is autophagy, an evolutionarily conserved process that leads to the vacuolar or lysosomal degradation of cytoplasmic components in eukaryotic cells. Here, we describe and contrast the extraplastidic pathways that degrade chloroplasts. This review shows that diverse pathways participate in chloroplast turnover during sugar starvation, senescence, and oxidative stress. Elucidating the mechanisms that regulate these pathways will help decipher the relationship among the diverse pathways mediating chloroplast protein turnover.

  7. Research on the influencing factors of measuring glomerular filtration rate through 99Tcm-DTPA renal dynamic imaging

    International Nuclear Information System (INIS)

    Huang Jianmin; Tang Zidu; Pan Liping; Liu Xiaomei; Xie Peng; Gao Jianqing

    2011-01-01

    Glomerular filtration rate (GFR) is an important criterion to estimate renal function. The most common way to measure GFR clinically is 99 Tc m -DTPA Renal Dynamic Imaging. However, the result may be influenced by many factors such as plasma protein binding, delineation of kidney and background region of interest, kidney depth, age and renal function and preparation of patient, nurse's operative technique, etc. The article analyzed each factor above respectively for clinical reference. (authors)

  8. 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

    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...... IUGR 30,900, and experimental IUGR 28,000 glomeruli per kidney). Mean glomerular volume was increased in both IUGR groups, which was associated with an increased proteinuria. It is concluded that IUGR leads to a nephron endowment with a compensatory glomerular enlargement. This compensation...... is associated with more proteinuria in the long run. Uterine artery ligation in the pregnant rat is a suitable model to study the effects of IUGR on the kidney....

  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 Diseases

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    ... is called a glomerulus , which comes from the Greek word meaning filter. The plural form of the ... primary indicator of Alport syndrome is a family history of chronic glomerular disease, although it may also ...

  11. Genetic Variation in Autophagy-Related Genes Influences the Risk and Phenotype of Buruli Ulcer.

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    Carlos Capela

    2016-04-01

    Full Text Available Buruli ulcer (BU is a severe necrotizing human skin disease caused by Mycobacterium ulcerans. Clinically, presentation is a sum of these diverse pathogenic hits subjected to critical immune-regulatory mechanisms. Among them, autophagy has been demonstrated as a cellular process of critical importance. Since microtubules and dynein are affected by mycolactone, the critical pathogenic exotoxin produced by M. ulcerans, cytoskeleton-related changes might potentially impair the autophagic process and impact the risk and progression of infection.Genetic variants in the autophagy-related genes NOD2, PARK2 and ATG16L1 has been associated with susceptibility to mycobacterial diseases. Here, we investigated their association with BU risk, its severe phenotypes and its progression to an ulcerative form.Genetic variants were genotyped using KASPar chemistry in 208 BU patients (70.2% with an ulcerative form and 28% in severe WHO category 3 phenotype and 300 healthy endemic controls.The rs1333955 SNP in PARK2 was significantly associated with increased susceptibility to BU [odds ratio (OR, 1.43; P = 0.05]. In addition, both the rs9302752 and rs2066842 SNPs in NOD2 gee significantly increased the predisposition of patients to develop category 3 (OR, 2.23; P = 0.02; and OR 12.7; P = 0.03, respectively, whereas the rs2241880 SNP in ATG16L1 was found to significantly protect patients from presenting the ulcer phenotype (OR, 0.35; P = 0.02.Our findings indicate that specific genetic variants in autophagy-related genes influence susceptibility to the development of BU and its progression to severe phenotypes.

  12. The glomerular parietal epithelial cell's responses are influenced by SM22 alpha levels.

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    Naito, Shokichi; Pippin, Jeffrey W; Shankland, Stuart J

    2014-11-06

    Studies have shown in several diseases initially affecting podocytes, that the neighboring glomerular parietal epithelial cells (PECs) are secondarily involved. The PEC response might be reparative under certain circumstances, yet injurious under others. The factors governing these are not well understood. We have shown that SM22α, an actin-binding protein considered a marker of smooth muscle differentiation, is upregulated in podocytes and PECs in several models of podocyte disease. However, the impact of SM22α levels on PECs is not known. Experimental glomerular disease, characterized by primary podocyte injury, was induced in aged-matched SM22α+/+ and SM22α-/-mice by intraperitoneal injection of sheep anti-rabbit glomeruli antibody. Immunostaining methods were employed on days 7 and 14 of disease. The number of PEC transition cells, defined as cells co-expressing a PEC protein (PAX2) and podocyte protein (Synaptopodin) was higher in diseased SM22α-/-mice compared with SM22α+/+mice. WT1 staining along Bowman's capsule is higher in diseased SM22α-/-mice. This was accompanied by increased PEC proliferation (measured by ki-67 staining), and an increase in immunostaining for the progenitor marker NCAM, in a subpopulation of PECs in diseased SM22α-/-mice. In addition, immunostaining for vimentin and alpha smooth muscle actin, markers of epithelial-to-mesenchymal transition (EMT), was lower in diseased SM22α-/-mice compared to diseased SM22α+/+mice. SM22α levels may impact how PECs respond following a primary podocyte injury in experimental glomerular disease. Absent/lower levels favor an increase in PEC transition cells and PECs expressing a progenitor marker, and a lower EMT rate compared to SM22α+/+mice, where SM22 levels are markedly increased in PECs.

  13. Influence of Acute High Glucose on Protein Abundance Changes in Murine Glomerular Mesangial Cells

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    Michelle T. Barati

    2016-01-01

    Full Text Available The effects of acute exposure to high glucose levels as experienced by glomerular mesangial cells in postprandial conditions and states such as in prediabetes were investigated using proteomic methods. Two-dimensional gel electrophoresis and matrix assisted laser desorption ionization time of flight mass spectrometry methods were used to identify protein expression patterns in immortalized rat mesangial cells altered by 2 h high glucose (HG growth conditions as compared to isoosmotic/normal glucose control (NG⁎ conditions. Unique protein expression changes at 2 h HG treatment were measured for 51 protein spots. These proteins could be broadly grouped into two categories: (1 proteins involved in cell survival/cell signaling and (2 proteins involved in stress response. Immunoblot experiments for a protein belonging to both categories, prohibitin (PHB, supported a trend for increased total expression as well as significant increases in an acidic PHB isoform. Additional studies confirmed the regulation of proteasomal subunit alpha-type 2 and the endoplasmic reticulum chaperone and oxidoreductase PDI (protein disulfide isomerase, suggesting altered ER protein folding capacity and proteasomal function in response to acute HG. We conclude that short term high glucose induces subtle changes in protein abundances suggesting posttranslational modifications and regulation of pathways involved in proteostasis.

  14. Corticosteroids decrease glomerular angiotensin receptors

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    Douglas, J.G.

    1987-03-01

    Angiotensin II (ANG II) receptors of glomerular mesangial cells are regulated in vivo by changes in Na balance, effects that are presumed to be secondary to changes in circulating ANG II. However, since changes in ANG II were accompanied by parallel changes in plasma aldosterone in all models tested, it is possible that aldosterone may have also participated in the modulation of glomerular ANG II receptors. To test this hypothesis, short-term aldosterone infusions within the physiological range were employed to favor actions that would be mediated through a high-affinity mineralocorticoid receptor. The glucocorticoid, dexamethasone, was also tested to determine the mineralocorticoid specificity of the response. Two infusion rates were associated with a decrease in glomerular /sup 125/I ANG II receptor density of 33 and 45%, respectively. Serum potassium and urinary Na/K ratio were lower in the aldosterone group. Spironolactone abolished the effect of aldosterone consistent with an action mediated through a specific mineralocorticoid receptor. These studies support the hypothesis that corticosteroids modulate glomerular ANG II receptors and validate the complexity of glomerular receptor modulation. The downregulation observed would be expected to diminish the ability of ANG II to influence glomerular hemodynamics in models such as mineralocorticoid and glucocorticoid-induced hypertension.

  15. Glomerular filtration rate

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    ... this 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 ...

  16. Influences of different dietary energy level on sheep testicular development associated with AMPK/ULK1/autophagy pathway.

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    Pang, Jing; Li, Fengzhe; Feng, Xu; Yang, Hua; Han, Le; Fan, Yixuan; Nie, Haitao; Wang, Zhen; Wang, Feng; Zhang, Yanli

    2018-03-01

    Energy balance is an important feature for spermatozoa production in the testis. The 5'-AMP-activated protein kinase (AMPK) is a sensor of cell energy, has been implicated as a mediator between gonadal function and energy balance. Herein, we intended to determine the physiological effects of AMPK on testicular development in feed energy restricted and compensated pre-pubertal rams. Lambs had restricted feeding for 2 months and then provided compensatory feeding for another 3 months. Feed levels were 100%(control), 15% and 30% of energy restriction (ER) diets, respectively. The results showed that lambs fed the 30% ER diet had significantly lower testicular weight (P energy requirement after restriction. Taken together, dietary energy levels influence testicular development through autophagy and apoptosis interplay mediated by AMPK-ULK1 signal pathway, which also indicates the important role of the actions of AMPK in the testis homeostasis. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. 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...... as a reference treatment to emphasize the differences between an MTOR-dependent and -independent autophagy-induction. By this means 5901 phosphosites were identified of which 626 were treatment-specific regulated and 175 were coregulated. Investigation of the ammonia-specific regulated sites supported that MTOR...

  18. Glomerular Disease in Women

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    Kate Wiles

    2018-03-01

    Full Text Available Gender differences exist in the prevalence of glomerular diseases. Data based on histological diagnosis underestimate the prevalence of preeclampsia, which is almost certainly the commonest glomerular disease in the world, and uniquely gender-specific. Glomerular disease affects fertility via disease activity, the therapeutic use of cyclophosphamide, and underlying chronic kidney disease. Techniques to preserve fertility during chemotherapy and risk minimization of artificial reproductive techniques are considered. The risks, benefits, and effectiveness of different contraceptive methods for women with glomerular disease are outlined. Glomerular disease increases the risk of adverse outcomes in pregnancy, including preeclampsia; yet, diagnosis of preeclampsia is complicated by the presence of hypertension and proteinuria that precede pregnancy. The role of renal biopsy in pregnancy is examined, in addition to the use of emerging angiogenic biomarkers. The safety of drugs prescribed for glomerular disease in relation to reproductive health is detailed. The impact of both gender and pregnancy on long-term prognosis is discussed.

  19. Autophagy, signaling and obesity

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    Lavallard, Vanessa J.; Meijer, Alfred J.; Codogno, Patrice; Gual, Philippe

    2012-01-01

    Autophagy is a cellular pathway crucial for development, differentiation, survival and homeostasis. Autophagy can provide protection against aging and a number of pathologies such as cancer, neurodegeneration, cardiac disease and infection. Recent studies have reported new functions of autophagy in

  20. Pathology of glomerular lipidosis.

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    Sato, Hiroshi; Takahashi, Nobuyuki; Sato, Emiko; Kisu, Kiyomi; Ito, Sadayoshi; Saito, Takao

    2014-04-01

    Glomerular lipid deposition is sometimes associated with a particular kind of lipid metabolism disturbance. Ultrastructural analyses using electron microscopy often indicate a disease-specific aspect of intraglomerular lipid distribution.

  1. Glomerular Lipidosis in Dogs.

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    Kohnken, Rebecca A; Amerman, Hayley; Brown, Cathy A; Furrow, Eva; Lees, George E; Cianciolo, Rachel E

    2017-09-01

    Glomerular lipidosis (GL) is characterized by dilated glomerular capillary loops containing lipid-laden cells (foam cells). Previously, GL was considered to be an incidental finding because affected dogs were typically not azotemic. However, the International Renal Interest Society staging system for canine chronic kidney disease has increased the awareness of other clinical parameters (eg, proteinuria and hypertension) that should be included in the assessment of renal function. As such, the aim of this study was to determine clinical abnormalities and concurrent renal lesions in dogs with GL. GL was identified in renal biopsies from 46 dogs evaluated by the International Veterinary Renal Pathology Service. GL was the sole diagnosis in 5 of 46 cases (11%), all of which were proteinuric. All 5 dogs had at least 1 additional clinicopathologic abnormality consistent with renal disease, including hypertension (4), azotemia (3), and/or hypoalbuminemia (2). The remaining 41 dogs had GL in combination with other glomerular lesions, the most common being focal segmental glomerulosclerosis (16, 35%), lesions consistent with juvenile nephropathy (8, 17%), and glomerular amyloidosis (5, 11%). Overall, dogs with severe GL were younger than were those with mild GL ( P < .001). The percentage of glomeruli affected by GL differed by concurrent diagnoses ( P = .034), with the highest percentage of affected glomeruli in dogs with GL alone or those with concurrent juvenile nephropathy. These findings suggest that GL should be a recognized histologic phenotype of glomerular injury associated with clinical renal dysfunction and/or juvenile nephropathies.

  2. Glomerular nephrotoxicity of aminoglycosides

    International Nuclear Information System (INIS)

    Martinez-Salgado, Carlos; Lopez-Hernandez, Francisco J.; Lopez-Novoa, Jose M.

    2007-01-01

    Aminoglycoside antibiotics are the most commonly used antibiotics worldwide in the treatment of Gram-negative bacterial infections. However, aminoglycosides induce nephrotoxicity in 10-20% of therapeutic courses. Aminoglycoside-induced nephrotoxicity is characterized by slow rises in serum creatinine, tubular necrosis and marked decreases in glomerular filtration rate and in the ultrafiltration coefficient. Regulation of the ultrafiltration coefficient depends on the activity of intraglomerular mesangial cells. The mechanisms responsible for tubular nephrotoxicity of aminoglycosides have been intensively reviewed previously, but glomerular toxicity has received less attention. The purpose of this review is to critically assess the published literature regarding the toxic mechanisms of action of aminoglycosides on renal glomeruli and mesangial cells. The main goal of this review is to provide an actualized and mechanistic vision of pathways involved in glomerular toxic effects of aminoglycosides

  3. Diadenosine pentaphosphate modulates glomerular arteriolar tone and glomerular filtration rate.

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    Patzak, A; Carlström, M; Sendeski, M M; Lai, E Y; Liu, Z Z; Sällström, J; Flöge, J; Heintz, B; Jankowski, J; Jankowski, V

    2015-01-01

    Mechanisms and participating substances involved in the reduction of glomerular filtration (GFR) in contrast-induced acute kidney injury (CI-AKI) are still matter of debate. We hypothesized that diadenosine polyphosphates are released by the action of contrast media on tubular cells and may act on glomerular arterioles and reduce GFR. Freshly isolated rat tubules were treated with the contrast medium iodixanol (47 mg iodine per mL) at 37 °C for 20 min. The content of Apn A (n = 3-6) in the supernatant of treated tubules and in the plasma of healthy persons and patients with AKI was analysed using reversed-phase chromatography, affinity chromatography and mass spectrometry. GFR was obtained in conscious mice by inulin clearance. Concentration response curves for Apn A (n = 3-6, 10(-12) -10(-5)  mol L(-1) ) were measured in isolated perfused glomerular arterioles. Iodixanol treatment of tubules significantly increased the concentration of Apn A (n = 3-5) in the supernatant. Ap6 A was below the detection limit. AKI patient shows higher concentrations of Apn A compared to healthy. Application of Ap5 A significantly reduced the GFR in conscious mice. Ap5 A reduced afferent arteriolar diameters, but did not influence efferent arterioles. The constrictor effect on afferent arterioles was strong immediately after application, but weakened with time. Then, non-selective P2 inhibitor suramin blocked the Ap5 A-induced constriction. The data suggest that Ap5 A plays a role in the pathophysiology of CI-AKI. We show a contrast media-induced release of Ap5 A from tubules, which might increase afferent arteriolar resistance and reduce the GFR. © 2014 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  4. Advances in Autophagy Regulatory Mechanisms

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    Laura E. Gallagher

    2016-05-01

    Full Text Available Autophagy plays a critical role in cell metabolism by degrading and recycling internal components when challenged with limited nutrients. This fundamental and conserved mechanism is based on a membrane trafficking pathway in which nascent autophagosomes engulf cytoplasmic cargo to form vesicles that transport their content to the lysosome for degradation. Based on this simple scheme, autophagy modulates cellular metabolism and cytoplasmic quality control to influence an unexpectedly wide range of normal mammalian physiology and pathophysiology. In this review, we summarise recent advancements in three broad areas of autophagy regulation. We discuss current models on how autophagosomes are initiated from endogenous membranes. We detail how the uncoordinated 51-like kinase (ULK complex becomes activated downstream of mechanistic target of rapamycin complex 1 (MTORC1. Finally, we summarise the upstream signalling mechanisms that can sense amino acid availability leading to activation of MTORC1.

  5. Autophagy, Metabolism, and Cancer.

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    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." ©2015

  6. Autophagy in brain ischemia

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    Alicja Kost

    2011-08-01

    Full Text Available Autophagy is an intracellular process of macromolecule and organelle degradation, which plays an important role both in maintaining homeostasis and in responding to various harmful stimuli. Recent studies clearly indicate upregulation of autophagy in neurons challenged with brain ischemia. In this paper we present biosynthesis of autophagosomes as well as the role and molecular mechanisms of basal and induced neuronal autophagy. We have also reviewed recently published papers concerning the potential role of autophagy in brain ischemia. Results of both in vivo and in vitro experimental studies indicate that signaling pathways related to autophagy might become a target of new neuroprotective strategies.

  7. 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.

  8. Autophagy in freshwater planarians.

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    González-Estévez, Cristina

    2008-01-01

    Planarians provide a new and emergent in vivo model organism to study autophagy. On the whole, maintaining the normal homeostatic balance in planarians requires continuous dynamic adjustment of many processes, including proliferation, apoptosis, differentiation, and autophagy. This makes them very different from other models where autophagy only occurs at very specific times and/or in very specific organs. This chapter aims to offer a general vision of planarians as a model organism, placing more emphasis on those characteristics related to autophagy and describing how autophagy fits into the processes of body remodeling during regeneration and starvation. We also define exactly what is known about autophagy in these organisms and we discuss the techniques available to study the relevant processes, as well as the techniques that are currently being developed. As such, this chapter will serve as a compilation of the techniques available to investigate autophagy in planarians.

  9. The Mucosal Immune System and Its Regulation by Autophagy.

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    Kabat, Agnieszka M; Pott, Johanna; Maloy, Kevin J

    2016-01-01

    The gastrointestinal tract presents a unique challenge to the mucosal immune system, which has to constantly monitor the vast surface for the presence of pathogens, while at the same time maintaining tolerance to beneficial or innocuous antigens. In the intestinal mucosa, specialized innate and adaptive immune components participate in directing appropriate immune responses toward these diverse challenges. Recent studies provide compelling evidence that the process of autophagy influences several aspects of mucosal immune responses. Initially described as a "self-eating" survival pathway that enables nutrient recycling during starvation, autophagy has now been connected to multiple cellular responses, including several aspects of immunity. Initial links between autophagy and host immunity came from the observations that autophagy can target intracellular bacteria for degradation. However, subsequent studies indicated that autophagy plays a much broader role in immune responses, as it can impact antigen processing, thymic selection, lymphocyte homeostasis, and the regulation of immunoglobulin and cytokine secretion. In this review, we provide a comprehensive overview of mucosal immune cells and discuss how autophagy influences many aspects of their physiology and function. We focus on cell type-specific roles of autophagy in the gut, with a particular emphasis on the effects of autophagy on the intestinal T cell compartment. We also provide a perspective on how manipulation of autophagy may potentially be used to treat mucosal inflammatory disorders.

  10. [Morphological analysis of autophagy].

    Science.gov (United States)

    Hua, Fang; Hu, Zhuo-wei

    2016-01-01

    Autophagy is an important homeostatic cellular recycling mechanism responsible for degrading injured or dysfunctional subcellular organelles and proteins in all living cells. The process of autophagy can be divided into three relatively independent steps: the initiation of phagophore, the formation of autophagosome and the maturation/degradation stage. Different morphological characteristics and molecular marker changes can be observed at these stages. Morphological approaches are useful to produce novel knowledge that would not be achieved through other experimental methods. Here we summarize the morphological methods in monitoring autophagy, the principles in data interpretation and the cautions that should be considered in the study of autophagy.

  11. Epigallocatechin-3-Gallate (EGCG Promotes Autophagy-Dependent Survival via Influencing the Balance of mTOR-AMPK Pathways upon Endoplasmic Reticulum Stress

    Directory of Open Access Journals (Sweden)

    Marianna Holczer

    2018-01-01

    Full Text Available The maintenance of cellular homeostasis is largely dependent on the ability of cells to give an adequate response to various internal and external stimuli. We have recently proposed that the life-and-death decision in endoplasmic reticulum (ER stress response is defined by a crosstalk between autophagy, apoptosis, and mTOR-AMPK pathways, where the transient switch from autophagy-dependent survival to apoptotic cell death is controlled by GADD34. The aim of the present study was to investigate the role of epigallocatechin-3-gallate (EGCG, the major polyphenol of green tea, in promoting autophagy-dependent survival and to verify the key role in connecting GADD34 with mTOR-AMPK pathways upon prolonged ER stress. Our findings, obtained by using HEK293T cells, revealed that EGCG treatment is able to extend cell viability by inducing autophagy. We confirmed that EGCG-induced autophagy is mTOR-dependent and PKA-independent; furthermore, it also required ULK1. We show that pretreatment of cells with EGCG diminishes the negative effect of GADD34 inhibition (by guanabenz or siGADD34 treatment on autophagy. EGCG was able to delay apoptotic cell death by upregulating autophagy-dependent survival even in the absence of GADD34. Our data suggest a novel role for EGCG in promoting cell survival via shifting the balance of mTOR-AMPK pathways in ER stress.

  12. Comparative aspects of glomerular filtration in vertebrates.

    Science.gov (United States)

    Yokota, S D; Benyajati, S; Dantzler, W H

    1985-01-01

    Glomerular ultrafiltration of the plasma is a fundamental component of vertebrate renal function. The importance of the glomerulus is reflected by its near-universal presence and great elaboration among the vertebrates. Although the general structural features and functional properties of the glomerulus appear to be largely similar among diverse groups, there exists considerable variation in the magnitude of the rate of filtration. The kidney is the primary vertebrate organ responsible for water and metabolic waste excretion, and glomerular filtration plays an important role in these functions. Therefore, the magnitude of the GFR appears to be influenced primarily by the rates of water influx and metabolism. Major phylogenetic differences in morphological, physiological and metabolic design have a decisive impact on the magnitude of the GFR. The endothermic classes, with more numerous glomeruli, high metabolic rates, and high ultrafiltration pressures, have proportionately higher rates of glomerular filtration than the ectothermic groups. As a group, the reptiles, with presumably the lowest rates of water influx, exhibit the lowest GFRs. Within each class, there are trends toward species with greater access to free water having higher GFRs (e.g. fresh water vs. marine; mesic vs. xeric. The clearest examples exist for the teleosts, with marine forms having lower GFRs than their fresh water relatives. The coupling of the GFR to environmental influences is also demonstrated by the response of the animal to environmentally imposed perturbations, such as dehydration. In terrestrial animals during dehydration, reductions in the rate of glomerular filtration occur reducing the rate of urinary water loss. And increases in GFR appears to be important in the rapid elimination of water loads in nonmammalian vertebrates. This short-term modulation of the GFR occurs by either changing glomerular plasma flow or glomerular capillary hydrostatic pressure, or both. In addition

  13. Autophagy in photodynamic therapy

    African Journals Online (AJOL)

    Macroautophagy (autophagy) is crucial for cell survival during starvation and plays important roles in ... The work in this area is still limited. Keywords: Autophagy, Photodynamic therapy, Apoptosis, Cancer. Tropical Journal of Pharmaceutical Research is indexed by Science .... photodynamic dosages did not result in.

  14. Dietary fat composition influences glomerular and proximal convoluted tubule cell structure and autophagic processes in kidneys from calorie-restricted mice.

    Science.gov (United States)

    Calvo-Rubio, Miguel; Burón, M Isabel; López-Lluch, Guillermo; Navas, Plácido; de Cabo, Rafael; Ramsey, Jon J; Villalba, José M; González-Reyes, José A

    2016-06-01

    Calorie restriction (CR) has been repeatedly shown to prevent cancer, diabetes, hypertension, and other age-related diseases in a wide range of animals, including non-human primates and humans. In rodents, CR also increases lifespan and is a powerful tool for studying the aging process. Recently, it has been reported in mice that dietary fat plays an important role in determining lifespan extension with 40% CR. In these conditions, animals fed lard as dietary fat showed an increased longevity compared with mice fed soybean or fish oils. In this paper, we study the effect of these dietary fats on structural and physiological parameters of kidney from mice maintained on 40% CR for 6 and 18 months. Analyses were performed using quantitative electron microcopy techniques and protein expression in Western blots. CR mitigated most of the analyzed age-related parameters in kidney, such as glomerular basement membrane thickness, mitochondrial mass in convoluted proximal tubules and autophagic markers in renal homogenates. The lard group showed improved preservation of several renal structures with aging when compared to the other CR diet groups. These results indicate that dietary fat modulates renal structure and function in CR mice and plays an essential role in the determination of health span in rodents. © 2016 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  15. The role of autophagy in modulation of neuroinflammation in microglia.

    Science.gov (United States)

    Su, P; Zhang, J; Wang, D; Zhao, F; Cao, Z; Aschner, M; Luo, W

    2016-04-05

    Microglia have multiple functions in regulating homeostasis in the central nervous system (CNS), and microglial inflammation is thought to play a role in the etiology of the neurodegenerative diseases. When endogenous or exogenous stimuli trigger disorders in microenvironmental homeostasis in CNS, microglia critically determine the fate of other neural cells. Recently, it was reported that autophagy might influence inflammation and activation of microglia. Though the interaction between autophagy and macrophages has been reported and reviewed in length, the role of autophagy in microglia has yet to be reviewed. Herein, we will highlight recent advances on the emerging role of autophagy in microglia, focusing on the regulation of autophagy during microglial inflammation, and the possible mechanism involved. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  16. Crosstalk of ER stress-mediated autophagy and ER-phagy: Involvement of UPR and the core autophagy machinery.

    Science.gov (United States)

    Song, Shuling; Tan, Jin; Miao, Yuyang; Zhang, Qiang

    2018-05-01

    Endoplasmic reticulum (ER) stress, a common cellular stress response, is closely related to the activation of autophagy that is an important and evolutionarily conserved mechanism for maintaining cellular homeostasis. Autophagy induced by ER stress mainly includes the ER stress-mediated autophagy and ER-phagy. The ER stress-mediated autophagy is characterized by the generation of autophagosomes that include worn-out proteins, protein aggregates, and damaged organelles. While the autophagosomes of ER-phagy selectively include ER membranes, and the double membranes also derive, at least in part, from the ER. The signaling pathways of IRE1α, PERK, ATF6, and Ca 2+ are necessary for the activation of ER stress-mediated autophagy, while the receptor-mediated selective ER-phagy degrades the ER is Atg40/FAM134B. The ER stress-mediated autophagy and ER-phagy not only have differences, but also have connections. The activation of ER-phagy requires the core autophagy machinery, and the ER-phagy may be a branch of ER stress-mediated autophagy that selectively targets the ER. However, the determined factors that control the changeover switch between ER stress-mediated autophagy and ER-phagy are largely obscure, which may be associated with the type of cells and the extent of stimulation. This review summarized the crosstalk between ER stress-mediated autophagy and ER-phagy and their signaling networks. Additionally, we discussed the possible factors that influence the type of autophagy induced by ER stress. © 2017 Wiley Periodicals, Inc.

  17. 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...

  18. Dengue Virus and Autophagy

    Directory of Open Access Journals (Sweden)

    Nicholas S. Heaton

    2011-08-01

    Full Text Available Several independent groups have published that autophagy is required for optimal RNA replication of dengue virus (DENV. Initially, it was postulated that autophagosomes might play a structural role in replication complex formation. However, cryo-EM tomography of DENV replication complexes showed that DENV replicates on endoplasmic reticulum (ER cisternae invaginations and not on classical autophagosomes. Recently, it was reported that autophagy plays an indirect role in DENV replication by modulating cellular lipid metabolism. DENV-induced autophagosomes deplete cellular triglycerides that are stored in lipid droplets, leading to increased β-oxidation and energy production. This is the first example of a virus triggering autophagy to modulate cellular physiology. In this review, we summarize these data and discuss new questions and implications for autophagy during DENV replication.

  19. Phosphatidylethanolamine positively regulates autophagy and longevity.

    Science.gov (United States)

    Rockenfeller, P; Koska, M; Pietrocola, F; Minois, N; Knittelfelder, O; Sica, V; Franz, J; Carmona-Gutierrez, D; Kroemer, G; Madeo, F

    2015-03-01

    Autophagy is a cellular recycling program that retards ageing by efficiently eliminating damaged and potentially harmful organelles and intracellular protein aggregates. Here, we show that the abundance of phosphatidylethanolamine (PE) positively regulates autophagy. Reduction of intracellular PE levels by knocking out either of the two yeast phosphatidylserine decarboxylases (PSD) accelerated chronological ageing-associated production of reactive oxygen species and death. Conversely, the artificial increase of intracellular PE levels, by provision of its precursor ethanolamine or by overexpression of the PE-generating enzyme Psd1, significantly increased autophagic flux, both in yeast and in mammalian cell culture. Importantly administration of ethanolamine was sufficient to extend the lifespan of yeast (Saccharomyces cerevisiae), mammalian cells (U2OS, H4) and flies (Drosophila melanogaster). We thus postulate that the availability of PE may constitute a bottleneck for functional autophagy and that organismal life or healthspan could be positively influenced by the consumption of ethanolamine-rich food.

  20. The effect of penbutolol on glomerular filtration

    International Nuclear Information System (INIS)

    Meyer, B.H.; Muller, F.O.; Lotter, M.G.; Iturralde, M.P.; Grigoleit, H.-G.

    1981-01-01

    Penbutolol, a new β-adrenoceptor blocker, was found to increase the glomerular filtration rate (GFR) significantly (16%) relative to placebo when administered orally in a dose of 40 mg daily for 7 consecutive days to healthy males. Measurements were performed after the seventh dose. In contrast, a single acute intravenous dose of penbutolol 4 mg did not influence the GFR, which was determined by means of a gamma counter after intravenous injection of technetium-99m diethylenetriamine-penta-acetic acid. Since penbutolol possesses moderate β-adrenomimetic activity, it is postulated that the observed increase in the GFR after oral penbutolol could be due to increased cardiac output at rest

  1. [Autophagy in the kidney].

    Science.gov (United States)

    Pallet, Nicolas

    2017-03-01

    Autophagy is a highly conserved, physiological, catabolic process, involving the lysosomal degradation of cytosolic components, including macromolecules (such as proteins and lipids) and cytosolic organelles. Autophagy is believed to be essential for the maintenance of cellular homeostasis, for a number of fundamental biological activities, and an important component of the complex response of cells to multiple forms of stress. Autophagy is involved in the pathogenesis of a number of clinically important disorders but, until recently, little was known about its connection to kidney diseases. However, there is now growing evidence that autophagy is specifically linked to the pathogenesis of important renal diseases such as acute kidney injury, diabetic nephropathy and polycystic kidney disease. However, an understanding of the precise role of autophagy in the course of kidney diseases is still in its infancy. The review points out areas of particular interest for future research, and also discusses the importance of such information on whether the pharmacologic agents that modulate autophagy are potentially usable as novel forms of treatment for various kidney diseases. © 2017 médecine/sciences – Inserm.

  2. Autophagy research Lessons from metabolism

    NARCIS (Netherlands)

    Meijer, Alfred J.

    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.

  3. Autophagy-related genes in Helicobacter pylori infection.

    Science.gov (United States)

    Tanaka, Shingo; Nagashima, Hiroyuki; Uotani, Takahiro; Graham, David Y; Yamaoka, Yoshio

    2017-06-01

    In vitro studies have shown that Helicobacter pylori (H. pylori) infection induces autophagy in gastric epithelial cells. However, prolonged exposure to H. pylori reduces autophagy by preventing maturation of the autolysosome. The alterations of the autophagy-related genes in H. pylori infection are not yet fully understood. We analyzed autophagy-related gene expression in H. pylori-infected gastric mucosa compared with uninfected gastric mucosa obtained from 136 Bhutanese volunteers with mild dyspeptic symptoms. We also studied single nucleotide polymorphisms (SNPs) of autophagy-related gene in 283 Bhutanese participants to identify the influence on susceptibility to H. pylori infection. Microarray analysis of 226 autophagy-related genes showed that 16 genes were upregulated (7%) and nine were downregulated (4%). We used quantitative reverse transcriptase polymerase chain reaction to measure mRNA levels of the downregulated genes (ATG16L1, ATG5, ATG4D, and ATG9A) that were core molecules of autophagy. ATG16L1 and ATG5 mRNA levels in H. pylori-positive specimens (n=86) were significantly less than those in H. pylori-negative specimens (n=50). ATG16L1 mRNA levels were inversely related to H. pylori density. We also compared SNPs of ATG16L1 (rs2241880) among 206 H. pylori-positive and 77 H. pylori-negative subjects. The odds ratio for the presence of H. pylori in the GG genotype was 0.40 (95% CI: 0.18-0.91) relative to the AA/AG genotypes. Autophagy-related gene expression profiling using high-throughput microarray analysis indicated that downregulation of core autophagy machinery genes may depress autophagy functions and possibly provide a better intracellular habit for H. pylori in gastric epithelial cells. © 2017 John Wiley & Sons Ltd.

  4. Toxic metals and autophagy.

    Science.gov (United States)

    Chatterjee, Sarmishtha; Sarkar, Shuvasree; Bhattacharya, Shelley

    2014-11-17

    The earth's resources are finite, and it can no longer be considered a source of inexhaustible bounty for the human population. However, this realization has not been able to contain the human desire for rapid industrialization. The collateral to overusing environmental resources is the high-level contamination of undesirable toxic metals, leading to bioaccumulation and cellular damage. Cytopathological features of biological systems represent a key variable in several diseases. A review of the literature revealed that autophagy (PCDII), a high-capacity process, may consist of selective elimination of vital organelles and/or proteins that intiate mechanisms of cytoprotection and homeostasis in different biological systems under normal physiological and stress conditions. However, the biological system does survive under various environmental stressors. Currently, there is no consensus that specifies a particular response as being a dependable biomarker of toxicology. Autophagy has been recorded as the initial response of a cell to a toxic metal in a concentration- and time-dependent manner. Various signaling pathways are triggered through cellular proteins and/or protein kinases that can lead to autophagy, apoptosis (or necroptosis), and necrosis. Although the role of autophagy in tumorigenesis is associated with promoting tumor cell survival and/or acting as a tumor suppressive mechanism, PCDII in metal-induced toxicity has not been extensively studied. The aim of this review is to analyze the comparative cytotoxicity of metals/metalloids and nanoparticles (As, Cd, Cr, Hg, Fe, and metal-NP) in cells enduring autophagy. It is noted that metals/metalloids and nanoparticles prefer ATG8/LC3 as a potent inducer of autophagy in several cell lines or animal cells. MAP kinases, death protein kinases, PI3K, AKT, mTOR, and AMP kinase have been found to be the major components of autophagy induction or inhibition in the context of cellular responses to metals/metalloids and

  5. Glomerular extracellular matrix components and integrins

    NARCIS (Netherlands)

    Sterk, L. M.; de Melker, A. A.; Kramer, D.; Kuikman, I.; Chand, A.; Claessen, N.; Weening, J. J.; Sonnenberg, A.

    1998-01-01

    It has become apparent that extracellular matrix components and their cellular receptors, the integrins, are important regulators of glomerular development and function. In this rapidly evolving field we studied the production of extracellular matrix components and integrins by rat glomerular

  6. Autophagy in plant pathogenic fungi.

    Science.gov (United States)

    Liu, Xiao-Hong; Xu, Fei; Snyder, John Hugh; Shi, Huan-Bin; Lu, Jian-Ping; Lin, Fu-Cheng

    2016-09-01

    Autophagy is a conserved cellular process that degrades cytoplasmic constituents in vacuoles. Plant pathogenic fungi develop special infection structures and/or secrete a range of enzymes to invade their plant hosts. It has been demonstrated that monitoring autophagy processes can be extremely useful in visualizing the sequence of events leading to pathogenicity of plant pathogenic fungi. In this review, we introduce the molecular mechanisms involved in autophagy. In addition, we explore the relationship between autophagy and pathogenicity in plant pathogenic fungi. Finally, we discuss the various experimental strategies available for use in the study of autophagy in plant pathogenic fungi. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Autophagy and Alzheimer's Disease: From Molecular Mechanisms to Therapeutic Implications.

    Science.gov (United States)

    Uddin, Md Sahab; Stachowiak, Anna; Mamun, Abdullah Al; Tzvetkov, Nikolay T; Takeda, Shinya; Atanasov, Atanas G; Bergantin, Leandro B; Abdel-Daim, Mohamed M; Stankiewicz, Adrian M

    2018-01-01

    Alzheimer's disease (AD) is the most common cause of progressive dementia in the elderly. It is characterized by a progressive and irreversible loss of cognitive abilities and formation of senile plaques, composed mainly of amyloid β (Aβ), and neurofibrillary tangles (NFTs), composed of tau protein, in the hippocampus and cortex of afflicted humans. In brains of AD patients the metabolism of Aβ is dysregulated, which leads to the accumulation and aggregation of Aβ. Metabolism of Aβ and tau proteins is crucially influenced by autophagy. Autophagy is a lysosome-dependent, homeostatic process, in which organelles and proteins are degraded and recycled into energy. Thus, dysfunction of autophagy is suggested to lead to the accretion of noxious proteins in the AD brain. In the present review, we describe the process of autophagy and its importance in AD. Additionally, we discuss mechanisms and genes linking autophagy and AD, i.e., the mTOR pathway, neuroinflammation, endocannabinoid system, ATG7, BCL2, BECN1, CDK5, CLU, CTSD, FOXO1, GFAP, ITPR1, MAPT, PSEN1, SNCA, UBQLN1 , and UCHL1 . We also present pharmacological agents acting via modulation of autophagy that may show promise in AD therapy. This review updates our knowledge on autophagy mechanisms proposing novel therapeutic targets for the treatment of AD.

  8. Endosome-mediated autophagy

    Science.gov (United States)

    Kondylis, Vangelis; van Nispen tot Pannerden, Hezder E.; van Dijk, Suzanne; ten Broeke, Toine; Wubbolts, Richard; Geerts, Willie J.; Seinen, Cor; Mutis, Tuna; Heijnen, Harry F.G.

    2013-01-01

    Activation of TLR signaling has been shown to induce autophagy in antigen-presenting cells (APCs). Using high-resolution microscopy approaches, we show that in LPS-stimulated dendritic cells (DCs), autophagosomes emerge from MHC class II compartments (MIICs) and harbor both the molecular machinery for antigen processing and the autophagosome markers LC3 and ATG16L1. This ENdosome-Mediated Autophagy (ENMA) appears to be the major type of autophagy in DCs, as similar structures were observed upon established autophagy-inducing conditions (nutrient deprivation, rapamycin) and under basal conditions in the presence of bafilomycin A1. Autophagosome formation was not significantly affected in DCs expressing ATG4BC74A mutant and atg4b−/− bone marrow DCs, but the degradation of the autophagy substrate SQSTM1/p62 was largely impaired. Furthermore, we demonstrate that the previously described DC aggresome-like LPS-induced structures (DALIS) contain vesicular membranes, and in addition to SQSTM1 and ubiquitin, they are positive for LC3. LC3 localization on DALIS is independent of its lipidation. MIIC-driven autophagosomes preferentially engulf the LPS-induced SQSTM1-positive DALIS, which become later degraded in autolysosomes. DALIS-associated membranes also contain ATG16L1, ATG9 and the Q-SNARE VTI1B, suggesting that they may represent (at least in part) a membrane reservoir for autophagosome expansion. We propose that ENMA constitutes an unconventional, APC-specific type of autophagy, which mediates the processing and presentation of cytosolic antigens by MHC class II machinery, and/or the selective clearance of toxic by-products of elevated ROS/RNS production in activated DCs, thereby promoting their survival. PMID:23481895

  9. DNA damage and autophagy

    International Nuclear Information System (INIS)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Panayiotidis, Mihalis I.; Franco, Rodrigo

    2011-01-01

    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.

  10. 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.

  11. 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.

  12. Autophagy in idiopathic pulmonary fibrosis.

    Directory of Open Access Journals (Sweden)

    Avignat S Patel

    Full Text Available Autophagy is a basic cellular homeostatic process important to cell fate decisions under conditions of stress. Dysregulation of autophagy impacts numerous human diseases including cancer and chronic obstructive lung disease. This study investigates the role of autophagy in idiopathic pulmonary fibrosis.Human lung tissues from patients with IPF were analyzed for autophagy markers and modulating proteins using western blotting, confocal microscopy and transmission electron microscopy. To study the effects of TGF-β(1 on autophagy, human lung fibroblasts were monitored by fluorescence microscopy and western blotting. In vivo experiments were done using the bleomycin-induced fibrosis mouse model.Lung tissues from IPF patients demonstrate evidence of decreased autophagic activity as assessed by LC3, p62 protein expression and immunofluorescence, and numbers of autophagosomes. TGF-β(1 inhibits autophagy in fibroblasts in vitro at least in part via activation of mTORC1; expression of TIGAR is also increased in response to TGF-β(1. In the bleomycin model of pulmonary fibrosis, rapamycin treatment is antifibrotic, and rapamycin also decreases expression of á-smooth muscle actin and fibronectin by fibroblasts in vitro. Inhibition of key regulators of autophagy, LC3 and beclin-1, leads to the opposite effect on fibroblast expression of á-smooth muscle actin and fibronectin.Autophagy is not induced in pulmonary fibrosis despite activation of pathways known to promote autophagy. Impairment of autophagy by TGF-β(1 may represent a mechanism for the promotion of fibrogenesis in IPF.

  13. Autophagy in Measles Virus Infection

    Directory of Open Access Journals (Sweden)

    Aurore Rozières

    2017-11-01

    Full Text Available Autophagy is a biological process that helps cells to recycle obsolete cellular components and which greatly contributes to maintaining cellular integrity in response to environmental stress factors. Autophagy is also among the first lines of cellular defense against invading microorganisms, including viruses. The autophagic destruction of invading pathogens, a process referred to as xenophagy, involves cytosolic autophagy receptors, such as p62/SQSTM1 (Sequestosome 1 or NDP52/CALCOCO2 (Nuclear Dot 52 KDa Protein/Calcium Binding And Coiled-Coil Domain 2, which bind to microbial components and target them towards growing autophagosomes for degradation. However, most, if not all, infectious viruses have evolved molecular tricks to escape from xenophagy. Many viruses even use autophagy, part of the autophagy pathway or some autophagy-associated proteins, to improve their infectious potential. In this regard, the measles virus, responsible for epidemic measles, has a unique interface with autophagy as the virus can induce multiple rounds of autophagy in the course of infection. These successive waves of autophagy result from distinct molecular pathways and seem associated with anti- and/or pro-measles virus consequences. In this review, we describe what the autophagy–measles virus interplay has taught us about both the biology of the virus and the mechanistic orchestration of autophagy.

  14. Glomerular hyperfiltration: definitions, mechanisms and clinical implications.

    Science.gov (United States)

    Helal, Imed; Fick-Brosnahan, Godela M; Reed-Gitomer, Berenice; Schrier, Robert W

    2012-02-21

    Glomerular hyperfiltration is a phenomenon that can occur in various clinical conditions including kidney disease. No single definition of glomerular hyperfiltration has been agreed upon, and the pathophysiological mechanisms, which are likely to vary with the underlying disease, are not well explored. Glomerular hyperfiltration can be caused by afferent arteriolar vasodilation as seen in patients with diabetes or after a high-protein meal, and/or by efferent arteriolar vasoconstriction owing to activation of the renin-angiotensin-aldosterone system, thus leading to glomerular hypertension. Glomerular hypertrophy and increased glomerular pressure might be both a cause and a consequence of renal injury; understanding the renal adaptations to injury is therefore important to prevent further damage. In this Review, we discuss the current concepts of glomerular hyperfiltration and the renal hemodynamic changes associated with this condition. A physiological state of glomerular hyperfiltration occurs during pregnancy and after consumption of high-protein meals. The various diseases that have been associated with glomerular hyperfiltration, either per nephron or per total kidney, include diabetes mellitus, polycystic kidney disease, secondary focal segmental glomerulosclerosis caused by a reduction in renal mass, sickle cell anemia, high altitude renal syndrome and obesity. A better understanding of the mechanisms involved in glomerular hyperfiltration could enable the development of new strategies to prevent progression of kidney disease.

  15. Measurement of glomerular filtration rate

    International Nuclear Information System (INIS)

    D'haene, E.G.M.

    1987-01-01

    Discussed are various methods for measuring the glomerular filtration rate in men. The unsuitability of the creatinine clearance is again emphasized. Based on comparative studies of Fawdry et al, it is stated that using the single-shot single sample methods by using theoretical distribution volumes is the obvious technique. In Dordrecht a program is developed based on the work of Tauxe et al on the analogy of the program for ERPF determination. Some patient studies are demonstrated. The GFR determination has some disadvantages however there are indications that by using the Captopril test the GFR determination is preferred above the ERPF measurement. 11 refs.; 6 figs.; 4 tabs

  16. Autophagy to Survive

    Directory of Open Access Journals (Sweden)

    Muzeyyen Izmirli

    2014-06-01

    Full Text Available Autophagy is the catabolic mechanism that involves cell degradation of unnecessary or dysfunctional cellular components through the actions of lysosomes. It helps to keep the cells alive in such cases like oxidative stress, lack of nutrients and growth factors providing recycling of intracellular molecules. However, it works as a part of metabolism regulation, morphogenesis, cell differentiation, senescence, cell death and immune system. As a result of impairment of this mechanism, pathological situations arise including cancer, neurodegenerative and infectious diseases. Consequently, researches about autophagy mechanism are important for the development of novel diagnosis, follow-up and treatment modalities in health problems. [Archives Medical Review Journal 2014; 23(3.000: 411-419

  17. 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.

  18. Schistosomal glomerular disease (a review

    Directory of Open Access Journals (Sweden)

    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.

  19. Chaperone-Mediated Autophagy

    Science.gov (United States)

    Bejarano, Eloy; Cuervo, Ana Maria

    2010-01-01

    Continuous renewal of intracellular components is required to preserve cellular functionality. In fact, failure to timely turnover proteins and organelles leads often to cell death and disease. Different pathways contribute to the degradation of intracellular components in lysosomes or autophagy. In this review, we focus on chaperone-mediated autophagy (CMA), a selective form of autophagy that modulates the turnover of a specific pool of soluble cytosolic proteins. Selectivity in CMA is conferred by the presence of a targeting motif in the cytosolic substrates that, upon recognition by a cytosolic chaperone, determines delivery to the lysosomal surface. Substrate proteins undergo unfolding and translocation across the lysosomal membrane before reaching the lumen, where they are rapidly degraded. Better molecular characterization of the different components of this pathway in recent years, along with the development of transgenic models with modified CMA activity and the identification of CMA dysfunction in different severe human pathologies and in aging, are all behind the recent regained interest in this catabolic pathway. PMID:20160146

  20. Autophagy and leucine promote chronological longevity and respiration proficiency during calorie restriction in yeast.

    Science.gov (United States)

    Aris, John P; Alvers, Ashley L; Ferraiuolo, Roy A; Fishwick, Laura K; Hanvivatpong, Amanda; Hu, Doreen; Kirlew, Christine; Leonard, Michael T; Losin, Kyle J; Marraffini, Michelle; Seo, Arnold Y; Swanberg, Veronica; Westcott, Jennifer L; Wood, Michael S; Leeuwenburgh, Christiaan; Dunn, William A

    2013-10-01

    We have previously shown that autophagy is required for chronological longevity in the budding yeast Saccharomyces cerevisiae. Here we examine the requirements for autophagy during extension of chronological life span (CLS) by calorie restriction (CR). We find that autophagy is upregulated by two CR interventions that extend CLS: water wash CR and low glucose CR. Autophagy is required for full extension of CLS during water wash CR under all growth conditions tested. In contrast, autophagy was not uniformly required for full extension of CLS during low glucose CR, depending on the atg allele and strain genetic background. Leucine status influenced CLS during CR. Eliminating the leucine requirement in yeast strains or adding supplemental leucine to growth media extended CLS during CR. In addition, we observed that both water wash and low glucose CR promote mitochondrial respiration proficiency during aging of autophagy-deficient yeast. In general, the extension of CLS by water wash or low glucose CR was inversely related to respiration deficiency in autophagy-deficient cells. Also, autophagy is required for full extension of CLS under non-CR conditions in buffered media, suggesting that extension of CLS during CR is not solely due to reduced medium acidity. Thus, our findings show that autophagy is: (1) induced by CR, (2) required for full extension of CLS by CR in most cases (depending on atg allele, strain, and leucine availability) and, (3) promotes mitochondrial respiration proficiency during aging under CR conditions. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Autophagy: Regulation by Energy Sensing

    NARCIS (Netherlands)

    Meijer, Alfred J.; Codogno, Patrice

    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

  2. Regulation of Autophagy by Kinases

    International Nuclear Information System (INIS)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda

    2011-01-01

    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

  3. 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.

  4. Regulation of Autophagy by Kinases

    Science.gov (United States)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda

    2011-01-01

    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. PMID:24212825

  5. Regulation of Autophagy by Kinases

    Directory of Open Access Journals (Sweden)

    Savitha Sridharan

    2011-06-01

    Full Text Available 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 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.

  6. Autophagy in plasma cell pathophysiology

    Directory of Open Access Journals (Sweden)

    Laura eOliva

    2014-03-01

    Full Text Available Plasma cells are the effectors responsible for antibody-mediated immunity. They differentiate from B lymphocytes through a complete remodeling of their original structure and function. Stress is a constitutive element of plasma cell differentiation. Macroautophagy, conventionally referred to as autophagy, is a conserved lysosomal recycling strategy that integrates cellular metabolism and enables adaptation to stress. In metazoa, autophagy plays diverse roles in cell differentiation. Recently, a number of autophagic functions have been recognized in innate and adaptive immunity, including clearance of intracellular pathogens, inflammasome regulation, lymphocyte ontogenesis, and antigen presentation. We identified a previously unrecognized role played by autophagy in plasma cell differentiation and activity. Following B cell activation, autophagy moderates the expression of the transcriptional repressor Blimp-1 and immunoglobulins through a selective negative control exerted on the size of the endoplasmic reticulum and its stress signaling response, including the essential plasma cell transcription factor, XBP-1. This containment of plasma cell differentiation and function, i.e., antibody production, is essential to optimize energy metabolism and viability. As a result, autophagy sustains antibody responses in vivo. Moreover, autophagy is an essential intrinsic determinant of long-lived plasma cells in their as yet poorly understood bone marrow niche. In this essay, we discuss these findings in the context of the established biological functions of autophagy, and their manifold implications for adaptive immunity and plasma cell diseases, in primis multiple myeloma.

  7. Autophagy is required for ectoplasmic specialization assembly in sertoli cells

    Science.gov (United States)

    Liu, Chao; Wang, Hongna; Shang, Yongliang; Liu, Weixiao; Song, Zhenhua; Zhao, Haichao; Wang, Lina; Jia, Pengfei; Gao, Fengyi; Xu, Zhiliang; Yang, Lin; Gao, Fei; Li, Wei

    2016-01-01

    ABSTRACT The ectoplasmic specialization (ES) is essential for Sertoli-germ cell communication to support all phases of germ cell development and maturity. Its formation and remodeling requires rapid reorganization of the cytoskeleton. However, the molecular mechanism underlying the regulation of ES assembly is still largely unknown. Here, we show that Sertoli cell-specific disruption of autophagy influenced male mouse fertility due to the resulting disorganized seminiferous tubules and spermatozoa with malformed heads. In autophagy-deficient mouse testes, cytoskeleton structures were disordered and ES assembly was disrupted. The disorganization of the cytoskeleton structures might be caused by the accumulation of a negative cytoskeleton organization regulator, PDLIM1, and these defects could be partially rescued by Pdlim1 knockdown in autophagy-deficient Sertoli cells. Altogether, our works reveal that the degradation of PDLIM1 by autophagy in Sertoli cells is important for the proper assembly of the ES, and these findings define a novel role for autophagy in Sertoli cell-germ cell communication. PMID:26986811

  8. Physiopathology glomerular hyperfiltration in diabetes. Part 1

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    Claudio A. Mascheroni

    2014-09-01

    Full Text Available Glomerular hyperfiltration (HF in diabetic kidney disease is a complex hemodynamic phenomenon which occurs in early stages of the disease’s progress and probably has negative influences, regarding the progression to the occurrence of microalbuminuria and the progress of evident diabetic nephropathy (DN. Factors involved in its physiopathology are numerous, they include: diabetic biochemical environment and several humoral factors like nitric oxide, prostaglandins, renin-angiotensin-aldosterone system, atrial natriuretic peptide, reactive oxygen species, other humoral and growth factors. These factors cause or enhance the vasodilatation of the afferent arteriole (AA. Factors with vasoconstriction function over the efferent arteriole, all considered primary vascular factors. However, these factors cannot explain other observed alterations and they constitute primary tubular abnormalities such as the increased reabsorption at the proximal tubule, probably conditioned by kidney growth in DBT and by the overexpression of the SGLT2 cotransporter. This higher proximal reabsorption would produce a lower arrival of solutes to the macula densa (MD. This would be incompatible with an action of the tubuloglomerular balance system, but it would be compatible with an action performed by the tubuloglomerular feedback system (TGFB that senses the decrease of the ClNa concentration at the MD. Also deactivating the TGFB and causing vasodilatation of the AA, resulting in an increase of glomerular filtration (GF and renal plasma flow (RPF, characteristic of the HF process. These two processes (vascular and tubular could act in synergy or simultaneously, depending on the metabolic and progressing conditions of the diabetic kidney disease. Similar mechanisms could explain the salt paradox, whereby a lowsalt diet would exacerbate the HF phenomenon and a high-salt diet would decrease the GF and the RPF, which could result in unexpected clinical implications. The

  9. Update on the glomerular filtration barrier.

    Science.gov (United States)

    Jarad, George; Miner, Jeffrey H

    2009-05-01

    The nephrology community lacks a unified view of protein sieving through the glomerular capillary wall. The glomerular capillary wall consists of three distinct but closely interacting layers: the fenestrated endothelium, with its glycocalyx; the podocytes, with their interdigitated foot processes and slit diaphragms; and the intervening glomerular basement membrane. Proteinuria is associated with abnormalities in any one layer, suggesting that each contributes to the glomerular filtration barrier (GFB). Proteinuria can also be induced in the context of a normal glomerular capillary wall. Here, we review some classic studies as well as some newer concepts and present competing hypotheses about the GFB. Two almost forgotten concepts have recently emerged. One group has challenged the exquisite selectivity of the GFB to albumin and suggested that proteinuria is the result of abnormal tubular uptake. There has also been a reemphasis on diffusion through the glomerular basement membrane as the driving force behind macromolecular filtration. New evidence suggests that the endothelial glycocalyx is an important charge-selective barrier. We suggest viewing the GFB as a dynamic rather than as a rigid barrier, requiring three healthy layers and a hemodynamic steady state. Multiple challenges to studying the endothelium, the tubular handling of albumin, and the role of hemodynamic forces will require new tools, new hypotheses, and open minds.

  10. 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.

  11. Cytotoxic Autophagy in Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Khushboo Sharma

    2014-06-01

    Full Text Available Autophagy is a process of cellular self-digestion, whereby the cell degrades subcellular materials in order to generate energy and metabolic precursors in order to prolong survival, classically under conditions of nutrient deprivation. Autophagy can also involve the degradation of damaged or aged organelles, and misfolded or damaged proteins to eliminate these components that might otherwise be deleterious to cellular survival. Consequently, autophagy has generally been considered a prosurvival response. Many, if not most chemotherapeutic drugs and radiation also promote autophagy, which is generally considered a cytoprotective response, in that its inhibition frequently promotes apoptotic cells death. Furthermore, it has been shown that conventional chemotherapeutic drugs and radiation alone rarely induce a form of autophagy that leads to cell death. However, there are multiple examples in the literature where newer chemotherapeutic agents, drug combinations or drugs in combination with radiation promote autophagic cell death. This review will describe autophagic cell death induced in breast tumor cells, lung cancer cells as well as glioblastoma, demonstrating that it cannot be concluded that stress induced autophagy is, of necessity, cytoprotective in function.

  12. Autophagy in human embryonic stem cells

    NARCIS (Netherlands)

    Tra, Thien; Gong, Lan; Kao, Lin-Pin; Li, Xue-Lei; Grandela, Catarina; Devenish, Rodney J.; Wolvetang, Ernst; Prescott, Mark

    2011-01-01

    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

  13. Enhanced myometrial autophagy in postpartum uterine involution

    Directory of Open Access Journals (Sweden)

    Keng-Fu Hsu

    2014-09-01

    Conclusion: Autophagy of myocytes may play an important role in uterine involution. These results have implications for our understanding of myometrial functional adaptations during pregnancy and the physiological role of autophagy in the uterine remodeling events in the postpartum period.

  14. 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.

  15. Documentation of renal glomerular and tubular impairment and glomerular hyperfiltration in multitransfused patients with beta thalassemia.

    Science.gov (United States)

    Deveci, Burak; Kurtoglu, Aysegul; Kurtoglu, Erdal; Salim, Ozan; Toptas, Tayfur

    2016-02-01

    Urinary albumin to creatinine (ACR) and beta2 microglobulin to creatinine ratios (BCR) are the surrogate and robust markers of renal glomerulopathy and tubulopathy, respectively. These markers predict short-term renal deterioration and mortality in various conditions. We aimed to assess the frequency and predictors of glomerular and tubular defects, renal impairment, and hyperfiltration in 96 adult patients with beta thalassemia intermedia and major. ACR > 300 mg/g creatinine and BCR > 300 μg/g creatinine were used to define the renal glomerular and tubular damages, respectively. Glomerular filtration rate (eGFRcreat) was estimated according to 2009 the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Decreased eGFRcreat was defined as less than 60 mL/min per 1.73 m(2). Renal glomerular and/or tubular defects were observed in about 68.8 % of all patients. Forty percent of patients had glomerular hyperfiltration. None of the patients had a decreased eGFRcreat. T2* value ≤20 msec on cardiac magnetic resonance (cMR) was the only independent predictor of glomerular damage (p = 0.013). Use of alendronate was associated with less renal tubular damage (p = 0.007). Female gender and previous history of splenectomy were the independent predictors of glomerular hyperfiltration in multivariate analysis (p glomerular damage is frequent in adult patients with thalassemia intermedia and major. T2* value on cMR was the only independent predictor of glomerular damage. However, since we did not explore all the parameters of iron, it is not possible to draw a definite conclusion about the association of cMR and glomerular damage. There is no association with cardiac iron overload/accumulation and tubular damage or hyperfiltration.

  16. Genetic analysis of intracapillary glomerular lipoprotein deposits in aging mice.

    Directory of Open Access Journals (Sweden)

    Gerda A Noordmans

    Full Text Available Renal aging is characterized by functional and structural changes like decreased glomerular filtration rate, and glomerular, tubular and interstitial damage. To gain insight in pathways involved in renal aging, we studied aged mouse strains and used genetic analysis to identify genes associated with aging phenotypes.Upon morphological screening in kidneys from 20-month-old mice from 26 inbred strains we noted intracapillary PAS-positive deposits. The severity of these deposits was quantified by scoring of a total of 50 glomeruli per section (grade 0-4. Electron microscopy and immunohistochemical staining for apoE, apoB, apoA-IV and perilipin-2 was performed to further characterize the lesions. To identify loci associated with these PAS-positive intracapillary glomerular deposits, we performed haplotype association mapping.Six out of 26 mouse strains showed glomerular PAS-positive deposits. The severity of these deposits varied: NOD(0.97, NZW(0.41, NON(0.30, B10(0.21, C3 H(0.9 and C57BR(0.7. The intracapillary deposits were strongly positive for apoE and weakly positive for apoB and apoA-IV. Haplotype association mapping showed a strong association with a 30-Kb haplotype block on Chr 1 within the Esrrg gene. We investigated 1 Mb on each site of this region, which includes the genes Spata17, Gpatch2, Esrrg, Ush2a and Kctd3.By analyzing 26 aged mouse strains we found that some strains developed an intracapillary PAS and apoE-positive lesion and identified a small haplotype block on Chr 1 within the Esrrg gene to be associated with these lipoprotein deposits. The region spanning this haplotype block contains the genes Spata17, Gpatch2, Esrrg, Ush2a and Kctd3, which are all highly expressed in the kidney. Esrrg might be involved in the evolvement of these glomerular deposits by influencing lipid metabolism and possibly immune reponses.

  17. Autophagy and Alzheimer’s Disease: From Molecular Mechanisms to Therapeutic Implications

    Directory of Open Access Journals (Sweden)

    Md. Sahab Uddin

    2018-01-01

    Full Text Available Alzheimer’s disease (AD is the most common cause of progressive dementia in the elderly. It is characterized by a progressive and irreversible loss of cognitive abilities and formation of senile plaques, composed mainly of amyloid β (Aβ, and neurofibrillary tangles (NFTs, composed of tau protein, in the hippocampus and cortex of afflicted humans. In brains of AD patients the metabolism of Aβ is dysregulated, which leads to the accumulation and aggregation of Aβ. Metabolism of Aβ and tau proteins is crucially influenced by autophagy. Autophagy is a lysosome-dependent, homeostatic process, in which organelles and proteins are degraded and recycled into energy. Thus, dysfunction of autophagy is suggested to lead to the accretion of noxious proteins in the AD brain. In the present review, we describe the process of autophagy and its importance in AD. Additionally, we discuss mechanisms and genes linking autophagy and AD, i.e., the mTOR pathway, neuroinflammation, endocannabinoid system, ATG7, BCL2, BECN1, CDK5, CLU, CTSD, FOXO1, GFAP, ITPR1, MAPT, PSEN1, SNCA, UBQLN1, and UCHL1. We also present pharmacological agents acting via modulation of autophagy that may show promise in AD therapy. This review updates our knowledge on autophagy mechanisms proposing novel therapeutic targets for the treatment of AD.

  18. Novel targets for Huntington’s disease in an mTOR-independent autophagy pathway

    Science.gov (United States)

    Williams, Andrea; Sarkar, Sovan; Cuddon, Paul; Ttofi, Evangelia K.; Saiki, Shinji; Siddiqi, Farah H.; Jahreiss, Luca; Fleming, Angeleen; Pask, Dean; Goldsmith, Paul; O’Kane, Cahir J.; Floto, R. Andres; Rubinsztein, David C.

    2009-01-01

    Autophagy is a major clearance route for intracellular aggregate-prone proteins causing diseases like Huntington’s disease. Autophagy induction with the mTOR inhibitor, rapamycin, accelerates clearance of these toxic substrates. As rapamycin has non-trivial side effects, we screened FDA-approved drugs to identify novel autophagy-inducing pathways. We found that L-type Ca2+ channel antagonists, the K+ATP channel opener minoxidil, and the Gi signaling activator clonidine, induce autophagy. These drugs revealed a cyclical mTOR-independent pathway regulating autophagy, where cAMP regulates IP3 levels, influencing calpain activity, which completes the cycle by cleaving and activating Gsα, which regulates cAMP levels. This pathway has numerous potential points where autophagy can be induced and we provide proof-of-principle for therapeutic relevance in Huntington’s disease using mammalian cell, fly and zebrafish models. Our data also suggest that insults that elevate intracytosolic Ca2+, like excitotoxicity, will inhibit autophagy, thus retarding clearance of aggregate-prone proteins. PMID:18391949

  19. Autophagy and Alzheimer’s Disease: From Molecular Mechanisms to Therapeutic Implications

    Science.gov (United States)

    Uddin, Md. Sahab; Stachowiak, Anna; Mamun, Abdullah Al; Tzvetkov, Nikolay T.; Takeda, Shinya; Atanasov, Atanas G.; Bergantin, Leandro B.; Abdel-Daim, Mohamed M.; Stankiewicz, Adrian M.

    2018-01-01

    Alzheimer’s disease (AD) is the most common cause of progressive dementia in the elderly. It is characterized by a progressive and irreversible loss of cognitive abilities and formation of senile plaques, composed mainly of amyloid β (Aβ), and neurofibrillary tangles (NFTs), composed of tau protein, in the hippocampus and cortex of afflicted humans. In brains of AD patients the metabolism of Aβ is dysregulated, which leads to the accumulation and aggregation of Aβ. Metabolism of Aβ and tau proteins is crucially influenced by autophagy. Autophagy is a lysosome-dependent, homeostatic process, in which organelles and proteins are degraded and recycled into energy. Thus, dysfunction of autophagy is suggested to lead to the accretion of noxious proteins in the AD brain. In the present review, we describe the process of autophagy and its importance in AD. Additionally, we discuss mechanisms and genes linking autophagy and AD, i.e., the mTOR pathway, neuroinflammation, endocannabinoid system, ATG7, BCL2, BECN1, CDK5, CLU, CTSD, FOXO1, GFAP, ITPR1, MAPT, PSEN1, SNCA, UBQLN1, and UCHL1. We also present pharmacological agents acting via modulation of autophagy that may show promise in AD therapy. This review updates our knowledge on autophagy mechanisms proposing novel therapeutic targets for the treatment of AD. PMID:29441009

  20. Autophagy Negatively Regulates Transmissible Gastroenteritis Virus Replication.

    Science.gov (United States)

    Guo, Longjun; Yu, Haidong; Gu, Weihong; Luo, Xiaolei; Li, Ren; Zhang, Jian; Xu, Yunfei; Yang, Lijun; Shen, Nan; Feng, Li; Wang, Yue

    2016-03-31

    Autophagy is an evolutionarily ancient pathway that has been shown to be important in the innate immune defense against several viruses. However, little is known about the regulatory role of autophagy in transmissible gastroenteritis virus (TGEV) replication. In this study, we found that TGEV infection increased the number of autophagosome-like double- and single-membrane vesicles in the cytoplasm of host cells, a phenomenon that is known to be related to autophagy. In addition, virus replication was required for the increased amount of the autophagosome marker protein LC3-II. Autophagic flux occurred in TGEV-infected cells, suggesting that TGEV infection triggered a complete autophagic response. When autophagy was pharmacologically inhibited by wortmannin or LY294002, TGEV replication increased. The increase in virus yield via autophagy inhibition was further confirmed by the use of siRNA duplexes, through which three proteins required for autophagy were depleted. Furthermore, TGEV replication was inhibited when autophagy was activated by rapamycin. The antiviral response of autophagy was confirmed by using siRNA to reduce the expression of gene p300, which otherwise inhibits autophagy. Together, the results indicate that TGEV infection activates autophagy and that autophagy then inhibits further TGEV replication.

  1. [Autophagy in the cardiovascular system].

    Science.gov (United States)

    Kheloufi, Marouane; Rautou, Pierre-Emmanuel; Boulanger, Chantal M

    2017-03-01

    Cardiovascular diseases are the leading cause of mortality worldwide. Studies regarding the role of autophagy in cardiac and vascular tissues have opened new therapeutic avenues to treat cardiovascular disorders. Altogether, these studies point out that autophagic activity needs to be maintained at an optimal level to preserve cardiovascular function. Reaching this goal constitutes a challenge for future efficient therapeutic strategies. The present review therefore highlights recent advances in the understanding of the role of autophagy in cardiovascular pathologies. © 2017 médecine/sciences – Inserm.

  2. Autophagy, lipophagy and lysosomal lipid storage disorders.

    Science.gov (United States)

    Ward, Carl; Martinez-Lopez, Nuria; Otten, Elsje G; Carroll, Bernadette; Maetzel, Dorothea; Singh, Rajat; Sarkar, Sovan; Korolchuk, Viktor I

    2016-04-01

    Autophagy is a catabolic process with an essential function in the maintenance of cellular and tissue homeostasis. It is primarily recognised for its role in the degradation of dysfunctional proteins and unwanted organelles, however in recent years the range of autophagy substrates has also been extended to lipids. Degradation of lipids via autophagy is termed lipophagy. The ability of autophagy to contribute to the maintenance of lipo-homeostasis becomes particularly relevant in the context of genetic lysosomal storage disorders where perturbations of autophagic flux have been suggested to contribute to the disease aetiology. Here we review recent discoveries of the molecular mechanisms mediating lipid turnover by the autophagy pathways. We further focus on the relevance of autophagy, and specifically lipophagy, to the disease mechanisms. Moreover, autophagy is also discussed as a potential therapeutic target in several key lysosomal storage disorders. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  3. 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.

  4. Crosstalk in glomerular injury and repair

    DEFF Research Database (Denmark)

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

    2015-01-01

    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...

  5. Glomerular Lesions in Proteinuric Miniature Schnauzer Dogs.

    Science.gov (United States)

    Furrow, E; Lees, G E; Brown, C A; Cianciolo, R E

    2017-05-01

    Miniature Schnauzer dogs are predisposed to idiopathic hypertriglyerceridemia, which increases risk for diseases such as pancreatitis and gallbladder mucocele. Recently, elevated triglyceride concentrations have been associated with proteinuria in this breed, although it is difficult to determine which abnormality is primary. Retrospective review of renal tissue from 27 proteinuric Miniature Schnauzers revealed that 20 dogs had ultrastructural evidence of osmophilic globules consistent with lipid in glomerular tufts. Seven of these dogs had lipid thromboemboli in glomerular capillary loops that distorted their shape and compressed circulating erythrocytes. Triglyceride concentrations were reported in 6 of these 7 dogs, and all were hypertriglyceridemic. In addition, glomerular lipidosis (defined as accumulation of foam cells within peripheral capillary loops) was identified in a single dog. The remaining 12 dogs had smaller amounts of lipid that could only be identified ultrastructurally. Neither signalment data nor clinicopathologic parameters (serum albumin, serum creatinine, urine protein-to-creatinine ratio, and blood pressure) differed among the various types of lipid lesions. During the time course of this study, all dogs diagnosed with glomerular lipid thromboemboli were Miniature Schnauzers, underscoring the importance of recognizing these clear spaces within capillary loops as lipid.

  6. Glomerular latency coding in artificial olfaction

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    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.

  7. Determination of glomerular filtration rate with radionuclide ...

    African Journals Online (AJOL)

    Mulligan JS, Blue PW, Hasbargen JA. Methods for measuring GFR with technetium-99m-OTPA: an analysis of several common methods. J Nucl Med. 1990; 31: 1211-1219. 4. Jackson JH. Blue PW. Ghaed N. Glomerular filtration rate determined in conjunction with routine renal scanning. Radiology 1985; 154: 203-205. 5.

  8. 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.

  9. Simplified method of radionuclide determination of glomerular filtration

    International Nuclear Information System (INIS)

    Butsev, Yu.A.

    1991-01-01

    Glomerular filtration is one of the chief components of renal function. The biochemical methods of its determination (clearance of insulin and endogeneous creatinine) have a number of shortcomings. The use of labelled glomerulotropic agents simplifies methods of the determination of glomerular filtration. A formula and a table of a glomerular filtration value per 1 kg of body mass were calculated

  10. 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

    2016-05-05

    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.

  11. Implications of Therapy-Induced Selective Autophagy on Tumor Metabolism and Survival

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    Luke R. K. Hughson

    2012-01-01

    Full Text Available Accumulating evidence indicates that therapies designed to trigger apoptosis in tumor cells cause mitochondrial depolarization, nuclear damage, and the accumulation of misfolded protein aggregates, resulting in the activation of selective forms of autophagy. These selective forms of autophagy, including mitophagy, nucleophagy, and ubiquitin-mediated autophagy, counteract apoptotic signals by removing damaged cellular structures and by reprogramming cellular energy metabolism to cope with therapeutic stress. As a result, the efficacies of numerous current cancer therapies may be improved by combining them with adjuvant treatments that exploit or disrupt key metabolic processes induced by selective forms of autophagy. Targeting these metabolic irregularities represents a promising approach to improve clinical responsiveness to cancer treatments given the inherently elevated metabolic demands of many tumor types. To what extent anticancer treatments promote selective forms of autophagy and the degree to which they influence metabolism are currently under intense scrutiny. Understanding how the activation of selective forms of autophagy influences cellular metabolism and survival provides an opportunity to target metabolic irregularities induced by these pathways as a means of augmenting current approaches for treating cancer.

  12. Vibroacustic microvibrations enhance kidney blood supply, glomerular filtration and glutathione peroxidase activity in spontaneously hypertensive rats.

    Science.gov (United States)

    Miloradović, Zoran; Mihailović-Stanojević, Nevena; Jovović, Đurđica; Ivanov, Milan; Vajić, Una J; Karanović, Danijela; Grujić Milanović, Jelica

    2015-01-01

    Limited numbers of studies include research of microvibration therapy in experimental models. We examined effects of chronic vibroacustic-microvibration treatment on haemodynamics and anti-oxidative defense in experimental hypertension. Study was performed on chronically treated hypertensive and normotensive Wistar rats. Mean arterial pressure (MAP), cardiac output (CO), renal blood flow (RBF), glomerular filtration and activity of anti-oxidative enzymes were determined after three weeks treatment. Vibroacustic treatment had no influence on MAP and CO, but RBF was increased in both groups of treated rats. Additionally, vibroacustic treatment enhanced diuresis and increased glomerular filtration in hypertensive rats. Glutathione peroxidase (GSH-Px) activity was elevated in both treated rat strains, but activity of superoxide dismutase was unchanged. We conclude that microvibration treatment doesn't ameliorate hypertension but improves renal blood supply (trough diminished renal vascular resistance), glomerular filtration, diuresis, and enhances glutathione dependent anti-oxidant defense with more important beneficials in hypertensive animals.

  13. Autophagy and IL-1 family cytokines

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    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.

  14. 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.

  15. Autophagy is essential for hearing in mice.

    Science.gov (United States)

    Fujimoto, Chisato; Iwasaki, Shinichi; Urata, Shinji; Morishita, Hideaki; Sakamaki, Yuriko; Fujioka, Masato; Kondo, Kenji; Mizushima, Noboru; Yamasoba, Tatsuya

    2017-05-11

    Hearing loss is the most frequent sensory disorder in humans. Auditory hair cells (HCs) are postmitotic at late-embryonic differentiation and postnatal stages, and their damage is the major cause of hearing loss. There is no measurable HC regeneration in the mammalian cochlea, and the maintenance of cell function is crucial for preservation of hearing. Here we generated mice deficient in autophagy-related 5 (Atg5), a gene essential for autophagy, in the HCs to investigate the effect of basal autophagy on hearing acuity. Deletion of Atg5 resulted in HC degeneration and profound congenital hearing loss. In autophagy-deficient HCs, polyubiquitinated proteins and p62/SQSTM1, an autophagy substrate, accumulated as inclusion bodies during the first postnatal week, and these aggregates increased in number. These findings revealed that basal autophagy has an important role in maintenance of HC morphology and hearing acuity.

  16. Osteoporosis and autophagy: What is the relationship?

    Directory of Open Access Journals (Sweden)

    Rinaldo Florencio-Silva

    Full Text Available Summary Autophagy is a survival pathway wherein non-functional proteins and organelles are degraded in lysosomes for recycling and energy production. Therefore, autophagy is fundamental for the maintenance of cell viability, acting as a quality control process that prevents the accumulation of unnecessary structures and oxidative stress. Increasing evidence has shown that autophagy dysfunction is related to several pathologies including neurodegenerative diseases and cancer. Moreover, recent studies have shown that autophagy plays an important role for the maintenance of bone homeostasis. For instance, in vitro and animal and human studies indicate that autophagy dysfunction in bone cells is associated with the onset of bone diseases such as osteoporosis. This review had the purpose of discussing the issue to confirm whether a relationship between autophagy dysfunction and osteoporosis exits.

  17. Pathophysiology of glomerular hyperfiltration in diabetes. Part II

    Directory of Open Access Journals (Sweden)

    Claudio Mascheroni

    2014-12-01

    Full Text Available Glomerular hyperfiltration (GH in diabetic renal disease is a complex hemodynamic phenomenon that occurs early in the course of the disease and most likely has associated with poor prognosis with respect to the development of microalbuminuria and overt diabetic nephropathy. The factors involved in its pathophysiology are multiple and include the diabetic milieu and the effects of several humoral factors such as nitric oxide, prostaglandins, renin angiotensin aldosterone system, atrial natriuretic peptide, reactive oxygen species and other humoral and growth factors that act basically causing or enhancing the afferent arteriole vasodilation (AA or vasoconstriction over the efferent arteriola, all considered primary vascular factors. However, these factors could not entirely explain other observed abnormalities that include primary tubular abnormalities such as increased reabsorption in the proximal tubule probably influenced by renal growth and cotransporter SGLT2 upregulation. This increased proximal reabsorption elicit a lower solute delivery to the dense macula, which would be incompatible with glomerulotubular balance function, but would with actions mediated by tubuloglomerular feedback (TGF that would sense low NaCl concentration at the MD, deactivating TGF and producing AA vasodilation, thereby increasing the glomerular filtration rate (GFR and renal plasma flow (RPF, characteristic of the GH process.

  18. Paradoxical glomerular filtration of carbon nanotubes.

    Science.gov (United States)

    Ruggiero, Alessandro; Villa, Carlos H; Bander, Evan; Rey, Diego A; Bergkvist, Magnus; Batt, Carl A; Manova-Todorova, Katia; Deen, William M; Scheinberg, David A; McDevitt, Michael R

    2010-07-06

    The molecular weight cutoff for glomerular filtration is thought to be 30-50 kDa. Here we report rapid and efficient filtration of molecules 10-20 times that mass and a model for the mechanism of this filtration. We conducted multimodal imaging studies in mice to investigate renal clearance of a single-walled carbon nanotube (SWCNT) construct covalently appended with ligands allowing simultaneous dynamic positron emission tomography, near-infrared fluorescence imaging, and microscopy. These SWCNTs have a length distribution ranging from 100 to 500 nm. The average length was determined to be 200-300 nm, which would yield a functionalized construct with a molecular weight of approximately 350-500 kDa. The construct was rapidly (t(1/2) approximately 6 min) renally cleared intact by glomerular filtration, with partial tubular reabsorption and transient translocation into the proximal tubular cell nuclei. Directional absorption was confirmed in vitro using polarized renal cells. Active secretion via transporters was not involved. Mathematical modeling of the rotational diffusivity showed the tendency of flow to orient SWCNTs of this size to allow clearance via the glomerular pores. Surprisingly, these results raise questions about the rules for renal filtration, given that these large molecules (with aspect ratios ranging from 100:1 to 500:1) were cleared similarly to small molecules. SWCNTs and other novel nanomaterials are being actively investigated for potential biomedical applications, and these observations-that high aspect ratio as well as large molecular size have an impact on glomerular filtration-will allow the design of novel nanoscale-based therapeutics with unusual pharmacologic characteristics.

  19. The role of autophagy in cardiac hypertrophy

    Science.gov (United States)

    Li, Lanfang; Xu, Jin; He, Lu; Peng, Lijun; Zhong, Qiaoqing; Chen, Linxi; Jiang, Zhisheng

    2016-01-01

    Autophagy is conserved in nature from lower eukaryotes to mammals and is an important self-cannibalizing, degradative process that contributes to the elimination of superfluous materials. Cardiac hypertrophy is primarily characterized by excess protein synthesis, increased cardiomyocyte size, and thickened ventricular walls and is a major risk factor that promotes arrhythmia and heart failure. In recent years, cardiomyocyte autophagy has been considered to play a role in controlling the hypertrophic response. However, the beneficial or aggravating role of cardiomyocyte autophagy in cardiac hypertrophy remains controversial. The exact mechanism of cardiomyocyte autophagy in cardiac hypertrophy requires further study. In this review, we summarize the controversies associated with autophagy in cardiac hypertrophy and provide insights into the role of autophagy in the development of cardiac hypertrophy. We conclude that future studies should emphasize the relationship between autophagy and the different stages of cardiac hypertrophy, as well as the autophagic flux and selective autophagy. Autophagy will be a potential therapeutic target for cardiac hypertrophy. PMID:27084518

  20. Approaches for Studying Autophagy in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Yanfang Chen

    2017-08-01

    Full Text Available Macroautophagy (hereafter referred to as autophagy is an intracellular degradative process, well conserved among eukaryotes. By engulfing cytoplasmic constituents into the autophagosome for degradation, this process is involved in the maintenance of cellular homeostasis. Autophagy induction triggers the formation of a cup-shaped double membrane structure, the phagophore, which progressively elongates and encloses materials to be removed. This double membrane vesicle, which is called an autophagosome, fuses with lysosome and forms the autolysosome. The inner membrane of the autophagosome, along with engulfed compounds, are degraded by lysosomal enzymes, which enables the recycling of carbohydrates, amino acids, nucleotides, and lipids. In response to various factors, autophagy can be induced for non-selective degradation of bulk cytoplasm. Autophagy is also able to selectively target cargoes and organelles such as mitochondria or peroxisome, functioning as a quality control system. The modification of autophagy flux is involved in developmental processes such as resistance to stress conditions, aging, cell death, and multiple pathologies. So, the use of animal models is essential for understanding these processes in the context of different cell types throughout the entire lifespan. For almost 15 years, the nematode Caenorhabditis elegans has emerged as a powerful model to analyze autophagy in physiological or pathological contexts. This review presents a rapid overview of physiological processes involving autophagy in Caenorhabditis elegans, the different assays used to monitor autophagy, their drawbacks, and specific tools for the analyses of selective autophagy.

  1. 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.

  2. Involvement of Autophagy in Coronavirus Replication

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    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. Starvation Promotes Autophagy-Associated Maturation of the Ovary in the Giant Freshwater Prawn, Macrobrachium rosenbergii

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    Wilairat Kankuan

    2017-05-01

    Full Text Available Limitation of food availability (starvation is known to influence the reproductive ability of animals. Autophagy is a lysosomal driven degradation process that protects the cell under metabolic stress conditions, such as during nutrient shortage. Whether, and how starvation-induced autophagy impacts on the maturation and function of reproductive organs in animals are still open questions. In this study, we have investigated the effects of starvation on histological and cellular changes that may be associated with autophagy in the ovary of the giant freshwater prawn, Macrobachium rosenbergii. To this end, the female prawns were daily fed (controls or unfed (starvation condition for up to 12 days, and the ovary tissue was analyzed at different time-points. Starvation triggered ovarian maturation, and concomitantly increased the expression of autophagy markers in vitellogenic oocytes. The immunoreactivities for autophagy markers, including Beclin1, LC3-II, and Lamp1, were enhanced in the late oocytes within the mature ovaries, especially at the vitellogenic stages. These markers co-localized with vitellin in the yolk granules within the oocytes, suggesting that autophagy induced by starvation could drive vitellin utilization, thus promoting ovarian maturation.

  4. Glycogen autophagy in glucose homeostasis.

    Science.gov (United States)

    Kotoulas, O B; Kalamidas, S A; Kondomerkos, D J

    2006-01-01

    Glycogen autophagy, the sequestration and degradation of cell glycogen in the autophagic vacuoles, is a selective, hormonally controlled and highly regulated process, representing a mechanism of glucose homeostasis under conditions of demand for the production of this sugar. In the newborn animals, this process is induced by glucagon secreted during the postnatal hypoglycemia and inhibited by insulin and parenteral glucose, which abolishes glucagon secretion. Hormonal action is mediated by the cAMP/protein kinase A (induction) and phosphoinositides/mTOR (inhibition) pathways that converge on common targets, such as the protein phosphatase 2A to regulate autophgosomal glycogen-hydrolyzing acid glucosidase and glycogen autophagy. Intralysosomal phosphate exchange reactions, which are affected by changes in the calcium levels and acid mannose 6- and acid glucose 6-phosphatase activities, can modify the intralysosomal composition in phosphorylated and nonphosphorylated glucose and promote the exit of free glucose through the lysosomal membrane. Glycogen autophagy-derived nonphosphorylated glucose assists the hyaloplasmic glycogen degradation-derived glucose 6-phosphate to combat postnatal hypoglycemia and participates in other metabolic pathways to secure the fine tuning of glucose homeostasis during the neonatal period.

  5. Interleukin-6: a bone marrow stromal cell paracrine signal that induces neuroendocrine differentiation and modulates autophagy in bone metastatic PCa cells.

    Science.gov (United States)

    Delk, Nikki A; Farach-Carson, Mary C

    2012-04-01

    Autophagy reallocates nutrients and clears normal cells of damaged proteins and organelles. In the context of metastatic disease, invading cancer cells hijack autophagic processes to survive and adapt in the host microenvironment. We sought to understand how autophagy is regulated in the metastatic niche for prostate cancer (PCa) cells where bone marrow stromal cell (BMSC) paracrine signaling induces PCa neuroendocrine differentiation (NED). In PCa, this transdifferentiation of metastatic PCa cells to neuronal-like cells correlates with advanced disease. Because autophagy provides a survival advantage for cancer cells and promotes cell differentiation, we hypothesized that autophagy mediates PCa NED in the bone. Thus, we determined the ability of paracrine factors in conditioned media (CM) from two separate BMSC subtypes, HS5 and HS27a, to induce autophagy in C4-2 and C4-2B bone metastatic PCa cells by characterizing the autophagy marker, LC3. Unlike HS27a CM, HS5 CM induced LC3 accumulation in PCa cells, suggesting autophagy was induced and indicating that HS5 and HS27a secrete a different milieu of paracrine factors that influence PCa autophagy. We identified interleukin-6 (IL-6), a cytokine more highly expressed in HS5 cells than in HS27a cells, as a paracrine factor that regulates PCa autophagy. Pharmacological inhibition of STAT3 activity did not attenuate LC3 accumulation, implying that IL-6 regulates NED and autophagy through different pathways. Finally, chloroquine inhibition of autophagic flux blocked PCa NED; hence autophagic flux maintains NED. Our studies imply that autophagy is cytoprotective for PCa cells in the bone, thus targeting autophagy is a potential therapeutic strategy.

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

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    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

  7. Autophagy: A Sweet Process in Diabetes

    NARCIS (Netherlands)

    Meijer, Alfred J.; Codogno, Patrice

    2008-01-01

    Autophagy is inhibited by the insulin-amino acid-mTOR signaling pathway. Two papers in this issue of Cell Metabolism (Ebato et al., 2008; Jung et al., 2008) provide evidence that basal autophagy is necessary to maintain the architecture and function of pancreatic beta cells and that its induction in

  8. Zinc starvation induces autophagy in yeast.

    Science.gov (United States)

    Kawamata, Tomoko; Horie, Tetsuro; Matsunami, Miou; Sasaki, Michiko; Ohsumi, Yoshinori

    2017-05-19

    Zinc is an essential nutrient for all forms of life. Within cells, most zinc is bound to protein. Because zinc serves as a catalytic or structural cofactor for many proteins, cells must maintain zinc homeostasis under severely zinc-deficient conditions. In yeast, the transcription factor Zap1 controls the expression of genes required for uptake and mobilization of zinc, but to date the fate of existing zinc-binding proteins under zinc starvation remains poorly understood. Autophagy is an evolutionarily conserved cellular degradation/recycling process in which cytoplasmic proteins and organelles are sequestered for degradation in the vacuole/lysosome. In this study, we investigated how autophagy functions under zinc starvation. Zinc depletion induced non-selective autophagy, which is important for zinc-limited growth. Induction of autophagy by zinc starvation was not directly related to transcriptional activation of Zap1. Instead, TORC1 inactivation directed zinc starvation-induced autophagy. Abundant zinc proteins, such as Adh1, Fba1, and ribosomal protein Rpl37, were degraded in an autophagy-dependent manner. But the targets of autophagy were not restricted to zinc-binding proteins. When cellular zinc is severely depleted, this non-selective autophagy plays a role in releasing zinc from the degraded proteins and recycling zinc for other essential purposes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Tumor Suppression and Promotion by Autophagy

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    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.

  10. Radiation-induced glomerular thrombus formation and nephropathy are not prevented by the ADP receptor antagonist clopidogrel

    International Nuclear Information System (INIS)

    Poele, Johannes A.M. te; Kleef, Ellen M. van; Wal, Anja F. van der; Dewit, Luc G.H.; Stewart, Fiona A.

    2001-01-01

    Purpose: To assess the effects of kidney irradiation on glomerular adenosine diphosphatase (ADPase) activity and intraglomerular microthrombus formation, and their correlation to the development of renal functional impairment. Methods and Materials: C3H/HenAf-nu + mice were given single-dose or fractionated kidney irradiations. Glomerular ADPase activity was measured using a cerium-based histochemical method. Microthrombus formation within the glomeruli was assessed by a semiquantitative immunohistochemical analysis of fibrinogen/fibrin deposits. Renal function was assessed by the [ 51 Cr]EDTA retention assay. Results: The ADPase activity was significantly reduced, to approximately 50% of pretreatment value, 4-40 weeks after 10-16 Gy single-dose irradiation and at 44 weeks after 20x2 Gy. No dose-effect relationship was found. An approximately fourfold increase in glomerular fibrinogen/fibrin staining was observed at 1 year after irradiation. This increase was not influenced by treating the mice with daily, oral clopidogrel, a platelet ADP receptor antagonist, which reduced platelet aggregation by more than 75%. Radiation-induced impairment of glomerular filtration was also not affected by the clopidogrel treatment. Conclusion: These data indicate that irradiation significantly reduced glomerular ADPase activity, which correlated with an increased glomerular fibrinogen/fibrin deposition. We were not able to reduce these prothrombotic changes, nor to protect against radiation nephropathy, by pharmacological intervention with an ADP-receptor antagonist

  11. METHODICAL BASES OF ESTIMATION GLOMERULAR FILTRATION RATE IN UROLOGICAL PRACTICE

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    M. M. Batiushin

    2017-01-01

    Full Text Available The article presents a review of methodological issues of estimation of glomerular filtration rate in urologic practice. Author examine the current international and national recommendations, in particular by KDIGO, the recommendations of the scientific society of nephrologists of Russia, Association of urologists of Russia, the results of comparative analysis of different methods of assessing glomerular filtration rate. It is shown that the currently calculated methods of assessment of glomerular filtration rate have advantages over technique of clearance. The advantages and disadvantages of methods for calculating glomerular filtration rate by the formula of Cockcroft-Gault and MDRD. The author lists the pathological conditions in urological practice, in which there is a need to assess glomerular filtration rate, given nomograms and links to online calculators for quick and easy calculation of glomerular filtration rate.

  12. Contribution of autophagy to antiviral immunity.

    Science.gov (United States)

    Rey-Jurado, Emma; Riedel, Claudia A; González, Pablo A; Bueno, Susan M; Kalergis, Alexis M

    2015-11-14

    Although identified in the 1960's, interest in autophagy has significantly increased in the past decade with notable research efforts oriented at understanding as to how this multi-protein complex operates and is regulated. Autophagy is commonly defined as a "self-eating" process evolved by eukaryotic cells to recycle senescent organelles and expired proteins, which is significantly increased during cellular stress responses. In addition, autophagy can also play important roles during human diseases, such as cancer, neurodegenerative and autoimmune disorders. Furthermore, novel findings suggest that autophagy contributes to the host defense against microbial infections. In this article, we review the role of macroautophagy in antiviral immune responses and discuss molecular mechanisms evolved by viral pathogens to evade this process. A role for autophagy as an effector mechanism used both, by innate and adaptive immunity is also discussed. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  13. Autophagy in endometriosis: Friend or foe?

    Science.gov (United States)

    Zhan, Lei; Li, Jun; Wei, Bing

    2018-01-01

    Endometriosis is a chronic, estrogen-dependent disease and characterized by the implantation of endometrial glands and stroma deep and haphazardly into the outside the uterine cavity. It affects an estimated 10% of the female population of reproductive age and results in obvious reduction in health-related quality of life. Unfortunately, there is no a consistent theory for the etiology of endometriosis. Furthermore, the endometriosis is hard to diagnose in early stage and the treatment methods are limited. Importantly, emerging evidence has investigated that there is a close relationship between endometriosis and autophagy. However, autophagy is a friend or foe in endometriosis is puzzling, the precise mechanism underlying autophagy in endometriosis has not been fully elucidated yet. Here, we provide an integrated view on the acquired findings of the connections between endometriosis and autophagy. We also discuss which may contribute to the abnormal level of autophagy in endometriosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Autophagy Proteins in Phagocyte Endocytosis and Exocytosis

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    Christian Münz

    2017-09-01

    Full Text Available Autophagy was initially described as a catabolic pathway that recycles nutrients of cytoplasmic constituents after lysosomal degradation during starvation. Since the immune system monitors products of lysosomal degradation via major histocompatibility complex (MHC class II restricted antigen presentation, autophagy was found to process intracellular antigens for display on MHC class II molecules. In recent years, however, it has become apparent that the molecular machinery of autophagy serves phagocytes in many more membrane trafficking pathways, thereby regulating immunity to infectious disease agents. In this minireview, we will summarize the recent evidence that autophagy proteins regulate phagocyte endocytosis and exocytosis for myeloid cell activation, pathogen replication, and MHC class I and II restricted antigen presentation. Selective stimulation and inhibition of the respective functional modules of the autophagy machinery might constitute valid therapeutic options in the discussed disease settings.

  15. Picornavirus Subversion of the Autophagy Pathway

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    William T. Jackson

    2011-08-01

    Full Text Available While autophagy has been shown to act as an anti-viral defense, the Picornaviridae avoid and, in many cases, subvert this pathway to promote their own replication. Evidence indicates that some picornaviruses hijack autophagy in order to induce autophagosome-like membrane structures for genomic RNA replication. Expression of picornavirus proteins can specifically induce the machinery of autophagy, although the mechanisms by which the viruses employ autophagy appear to differ. Many picornaviruses up-regulate autophagy in order to promote viral replication while some members of the family also inhibit degradation by autolysosomes. Here we explore the unusual relationship of this medically important family of viruses with a degradative mechanism of innate immunity.

  16. Picornavirus subversion of the autophagy pathway.

    Science.gov (United States)

    Klein, Kathryn A; Jackson, William T

    2011-09-01

    While autophagy has been shown to act as an anti-viral defense, the Picornaviridae avoid and, in many cases, subvert this pathway to promote their own replication. Evidence indicates that some picornaviruses hijack autophagy in order to induce autophagosome-like membrane structures for genomic RNA replication. Expression of picornavirus proteins can specifically induce the machinery of autophagy, although the mechanisms by which the viruses employ autophagy appear to differ. Many picornaviruses up-regulate autophagy in order to promote viral replication while some members of the family also inhibit degradation by autolysosomes. Here we explore the unusual relationship of this medically important family of viruses with a degradative mechanism of innate immunity.

  17. Glomerular development--shaping the multi-cellular filtration unit.

    Science.gov (United States)

    Schell, C; Wanner, N; Huber, T B

    2014-12-01

    The glomerulus represents a highly structured filtration unit, composed of glomerular endothelial cells, mesangial cells, podocytes and parietal epithelial cells. During glomerulogenesis an intricate network of signaling pathways involving transcription factors, secreted factors and cell-cell communication is required to guarantee accurate evolvement of a functional, complex 3-dimensional glomerular architecture. Here, we want to provide an overview on the critical steps and relevant signaling cascades of glomerular development. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Hypercholesterolemia downregulates autophagy in the rat heart.

    Science.gov (United States)

    Giricz, Zoltán; Koncsos, Gábor; Rajtík, Tomáš; Varga, Zoltán V; Baranyai, Tamás; Csonka, Csaba; Szobi, Adrián; Adameová, Adriana; Gottlieb, Roberta A; Ferdinandy, Péter

    2017-03-23

    We have previously shown that efficiency of ischemic conditioning is diminished in hypercholesterolemia and that autophagy is necessary for cardioprotection. However, it is unknown whether isolated hypercholesterolemia disturbs autophagy or the mammalian target of rapamycin (mTOR) pathways. Therefore, we investigated whether isolated hypercholesterolemia modulates cardiac autophagy-related pathways or programmed cell death mechanisms such as apoptosis and necroptosis in rat heart. Male Wistar rats were fed either normal chow (NORM; n = 9) or with 2% cholesterol and 0.25% cholic acid-enriched diet (CHOL; n = 9) for 12 weeks. CHOL rats exhibited a 41% increase in plasma total cholesterol level over that of NORM rats (4.09 mmol/L vs. 2.89 mmol/L) at the end of diet period. Animals were sacrificed, hearts were excised and briefly washed out. Left ventricles were snap-frozen for determination of markers of autophagy, mTOR pathway, apoptosis, and necroptosis by Western blot. Isolated hypercholesterolemia was associated with a significant reduction in expression of cardiac autophagy markers such as LC3-II, Beclin-1, Rubicon and RAB7 as compared to controls. Phosphorylation of ribosomal S6, a surrogate marker for mTOR activity, was increased in CHOL samples. Cleaved caspase-3, a marker of apoptosis, increased in CHOL hearts, while no difference in the expression of necroptotic marker RIP1, RIP3 and MLKL was detected between treatments. This is the first comprehensive analysis of autophagy and programmed cell death pathways of apoptosis and necroptosis in hearts of hypercholesterolemic rats. Our data show that isolated hypercholesterolemia suppresses basal cardiac autophagy and that the decrease in autophagy may be a result of an activated mTOR pathway. Reduced autophagy was accompanied by increased apoptosis, while cardiac necroptosis was not modulated by isolated hypercholesterolemia. Decreased basal autophagy and elevated apoptosis may be responsible for the

  19. WNK1 is an unexpected autophagy inhibitor

    Science.gov (United States)

    Gallolu Kankanamalage, Sachith; Lee, A-Young; Wichaidit, Chonlarat; Lorente-Rodriguez, Andres; Shah, Akansha M.; Stippec, Steve; Whitehurst, Angelique W.; Cobb, Melanie H.

    2017-01-01

    ABSTRACT Autophagy is a cellular degradation pathway that is essential to maintain cellular physiology, and deregulation of autophagy leads to multiple diseases in humans. In a recent study, we discovered that the protein kinase WNK1 (WNK lysine deficient protein kinase 1) is an inhibitor of autophagy. The loss of WNK1 increases both basal and starvation-induced autophagy. In addition, the depletion of WNK1 increases the activation of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex, which is required to induce autophagy. Moreover, the loss of WNK1 increases the expression of ULK1 (unc-51 like kinase 1), which is upstream of the PtdIns3K complex. It also increases the pro-autophagic phosphorylation of ULK1 at Ser555 and the activation of AMPK (AMP-activated protein kinase), which is responsible for that phosphorylation. The inhibition of AMPK by compound C decreases the magnitude of autophagy induction following WNK1 loss; however, it does not prevent autophagy induction. We found that the UVRAG (UV radiation resistance associated gene), which is a component of the PtdIns3K, binds to the N-terminal region of WNK1. Moreover, WNK1 partially colocalizes with UVRAG and this colocalization decreases when autophagy is stimulated in cells. The loss of WNK1 also alters the cellular distribution of UVRAG. The depletion of the downstream target of WNK1, OXSR1/OSR1 (oxidative-stress responsive 1) has no effect on autophagy, whereas the depletion of its relative STK39/SPAK (serine/threonine kinase 39) induces autophagy under nutrient-rich and starved conditions. PMID:28282258

  20. Impairment in glomerular filtration rate or glomerular filtration barrier and occurrence of stroke.

    Science.gov (United States)

    Ovbiagele, Bruce

    2008-07-01

    Chronic kidney disease (CKD) is associated with substantial burden and is a strong risk factor for cardiovascular disease. However, data on the relationship between CKD and stroke are few and are limited by unreliable or inadequate assessment of renal function. To properly assess the relationship between renal insufficiency and stroke in stroke survivors in the United States by simultaneously examining the effect of guideline-recommended indices of renal disease that measure glomerular filtration rate (creatinine clearance) and glomerular filtration barrier (proteinuria). Cross sectional. Nationally representative survey of the United States. Participants aged 55 or older who participated in the National Health and Nutrition Examination Survey from 1999 to 2004. Indices of renal disease that measure glomerular filtration rate (creatinine clearance) and glomerular filtration barrier (microalbuminuria). Of 6382 adults who met inclusion criteria, 5624 (88%) had full and complete data, of which 414 (6%) reported having had a stroke. Stroke survivors were older and more likely to have CKD, diabetes, hypertension, coronary artery disease, elevated blood pressure, increased glycohemoglobin concentration, and lower hematocrit compared with respondents who did not report stroke. Multivariate models showed that microalbuminuria (odds ratio, 1.51; 95% confidence interval, 1.02-2.24), decreased glomerular filtration rate (odds ratio, 1.93; 95% confidence interval, 1.28-2.91), and stage 3 CKD (odds ratio, 2.09; 95% confidence interval, 1.38-3.16) were significantly associated with stroke. Stroke is independently associated with impairment in structure and function of the glomerulus, which supports the need to consider screening patients with stroke for CKD and to simultaneously assess for both indices of renal disease.

  1. The Crosstalk between ROS and Autophagy in the Field of Transplantation Medicine

    Directory of Open Access Journals (Sweden)

    Anne C. Van Erp

    2017-01-01

    Full Text Available Many factors during the transplantation process influence posttransplant graft function and survival, including donor type and age, graft preservation methods (cold storage, machine perfusion, and ischemia-reperfusion injury. Successively, they will lead to cellular and molecular alterations that determine cell and ultimately organ fate. Oxidative stress and autophagy are implicated in posttransplant outcome since they are both affected by the stress responses triggered in each step (donor, preservation, and recipient of the transplantation process. Furthermore, oxidative stress influences autophagy and vice versa. Interestingly, both processes have positive as well as negative effects on graft outcome, suggesting they are tightly linked during the transplantation process. In this review, we discuss the importance, regulation and crosstalk of oxidative signals, and autophagy in the field of transplantation medicine.

  2. HUMAN GLOMERULAR VOLUME QUANTIFICATIONDURING THE AGING PROCESS

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    Dejan Zdravković

    2004-12-01

    Full Text Available Kidney function is directly related to the changes of renal tissue, especially glomeruli, which is particularly distinct during the aging process. The impossibility of kidney function substitution points to the need for glomerular morphologic and functional characteristics estimation during the aging process.Human cadaveric kidney tissue samples were used as material during research. Age of cadavers ranged from 20 to 70 years and they were classified according to the scheme: I (20–29; II (30–39; III (40–49; IV (50–59; V (60–69 i VI (older than 70. After the routine histologic preparation of the renal tissue the slices were analized stereologicaly under the light microscope with projection screen (Reichert Visopan with 40 x lens magnification. M42 test system was used and 100, by unbased method selected glomeruli, were analyzed.Average glomerular capillary network volume shows significant increase (p< 0,001 as far as to the age of 50 years in regard to the age of 20 to 29 years. This parameter shows insignificant decrease after the age of 50 until the age of 70 years. This decrease was significant after the age of 70 years in regard to the period of the 20 to 29 (p< 0,05 and the period of 40 to 49 years (p<0,01.

  3. Glomerular Filtration Rate is Unchanged By Ultramarathon.

    Science.gov (United States)

    Wołyniec, Wojciech; Ratkowski, Wojciech; Kasprowicz, Katarzyna; Jastrzębski, Zbigniew; Małgorzewicz, Sylwia; Witek, Konrad; Grzywacz, Tomasz; Żmijewski, Piotr; Renke, Marcin

    2017-12-27

    Acute kidney injury (AKI) is reported as a common complication of marathon and ultramarathon running. In previous studies AKI was diagnosed on the basis of the creatinine level in serum and estimated glomerular filtration rate (eGFR). In the present study we calculated eGFR and also measured creatinine clearance after every 25 km of a 100 km run. 20 healthy, amateur runners (males, mean age 40.75 ± 7.15 years, mean weight 76.87 ± 8.39 kg) took part in a 100 km run on a track. Blood and urine were collected before the run, after every 25 km and 12 hours after the run. 17 runners completed the study. There was increase in creatinine, urea and uric acid observed after 100 km (p AKIN) criteria of AKI. The eGFR according to the MDRD (modification of diet in renal disease), CKD-EPI (chronic kidney disease epidemiology collaboration) and Cockcroft-Gault formulas was significantly decreased after the run (p < 0.05). Otherwise, creatinine clearance calculated from creatinine level in both serum and urine remained stable. In contrast to the majority of previous studies, we did not observe any decrease in the kidney function during an ultramarathon. In this study the creatinine clearance, which is the best routine laboratory method to determine glomerular filtration rate was used. There is no evidence that long running is harmful for kidney.

  4. Mitochondria mediate septin cage assembly to promote autophagy of Shigella.

    Science.gov (United States)

    Sirianni, Andrea; Krokowski, Sina; Lobato-Márquez, Damián; Buranyi, Stephen; Pfanzelter, Julia; Galea, Dieter; Willis, Alexandra; Culley, Siân; Henriques, Ricardo; Larrouy-Maumus, Gerald; Hollinshead, Michael; Sancho-Shimizu, Vanessa; Way, Michael; Mostowy, Serge

    2016-07-01

    Septins, cytoskeletal proteins with well-characterised roles in cytokinesis, form cage-like structures around cytosolic Shigella flexneri and promote their targeting to autophagosomes. However, the processes underlying septin cage assembly, and whether they influence S. flexneri proliferation, remain to be established. Using single-cell analysis, we show that the septin cages inhibit S. flexneri proliferation. To study mechanisms of septin cage assembly, we used proteomics and found mitochondrial proteins associate with septins in S. flexneri-infected cells. Strikingly, mitochondria associated with S. flexneri promote septin assembly into cages that entrap bacteria for autophagy. We demonstrate that the cytosolic GTPase dynamin-related protein 1 (Drp1) interacts with septins to enhance mitochondrial fission. To avoid autophagy, actin-polymerising Shigella fragment mitochondria to escape from septin caging. Our results demonstrate a role for mitochondria in anti-Shigella autophagy and uncover a fundamental link between septin assembly and mitochondria. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  5. Autophagy and apoptosis in planarians.

    Science.gov (United States)

    González-Estévez, Cristina; Saló, Emili

    2010-03-01

    Adult planarians are capable of undergoing regeneration and body remodelling in order to adapt to physical damage or extreme environmental conditions. Moreover, most planarians can tolerate long periods of starvation and during this time, they shrink from an adult size to, and sometimes beyond, the initial size at hatching. Indeed, these properties have made them a classic model to study stem cells and regeneration. Under such stressful conditions, food reserves from the gastrodermis and parenchyma are first used up and later the testes, copulatory organs and ovaries are digested. More surprisingly, when food is again made available to shrunken individuals, they grow back to adult size and all their reproductive structures reappear. These cycles of growth and shrinkage may occur over long periods without any apparent impairment to the individual, or to its future maturation and breeding capacities. This plasticity resides in a mesoderm tissue known as the parenchyma, which is formed by several differentiated non-proliferating cell types and only one mitotically active cell type, the neoblasts, which represent approximately 20-30% of the cells in the parenchyma. Neoblasts are generally thought to be somatic stem-cells that participate in the normal continuous turnover of all cell types in planarians. Hence, planarians are organisms that continuously adapt their bodies (morphallaxis) to different environmental stresses (i.e.: injury or starvation). This adaptation involves a variety of processes including proliferation, differentiation, apoptosis and autophagy, all of which are perfectly orchestrated and tightly regulated to remodel or restore the body pattern. While neoblast biology and body re-patterning are currently the subject of intense research, apoptosis and autophagy remain much less studied. In this review we will summarize our current understanding and hypotheses regarding where and when apoptosis and autophagy occur and fulfil an essential role in

  6. Glomerular filtration rate estimation: performance of serum cystatin C-based prediction equations.

    Science.gov (United States)

    Weinert, Letícia Schwerz; Camargo, Eduardo Guimarães; Soares, Ariana A; Silveiro, Sandra Pinho

    2011-11-01

    Serum creatinine measurement is a mainstay in the routine laboratory evaluation of renal function, despite of having several disadvantages. Cystatin C, on the other hand, suffers less influence of gender and muscle mass and has been proposed as a more sensitive marker for glomerular filtration rate. However, serum endogenous markers should not be used alone to assess glomerular filtration rate. Creatinine-based equations such as the modification of diet in renal disease (MDRD) and Cockcroft-Gault are widely used despite their limitations. A large number of cystatin C-based prediction equations were developed in recent years, in diverse populations, with different laboratory assays and methods. Several studies demonstrated that cystatin C-based equations are reliable markers of glomerular filtration rate and can be used for diagnosis, evaluation and follow-up of kidney disease. They are simpler than creatinine-based equations and have at least the same accuracy and precision for glomerular filtration rate estimation. In conclusion, diabetes mellitus, cystic fibrosis, kidney transplantation, HIV-infection, and cirrhosis are clinical situations where cystatin C-based equations can be useful. Extremes of age such as childhood and advanced age have also been evaluated with favorable results.

  7. Not all autophagy is equal

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    Czyzyk-Krzeska, Maria F.; Meller, Jarek; Plas, David R.

    2012-01-01

    Autophagy is an important mechanism in cancer cell survival and tumor growth and plays both pro- and anti-oncogenic roles. However, the biochemical basis for these diverse functions is not well understood. Our work provides new evidence for the existence of two separate autophagic programs regulated in an opposite manner by the von Hippel-Lindau tumor suppressor (VHL). These programs, marked by differential requirements for LC3B vs. LC3C, play tumor-promoting and tumor-suppressing roles in re...

  8. 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.

  9. Autophagy in lung disease pathogenesis and therapeutics

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    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.

  10. Autophagy in Mycobacterium tuberculosis and HIV infections

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    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.

  11. Autophagy and BNIP3 protein in tumorogenesis

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    Ewelina Świderek

    2013-05-01

    Full Text Available Autophagy is a process necessary for maintaining cell homeostasis in physiological conditions, as well as during certain stresses like nutrients or oxygen deprivation. Autophagy also plays an essential role in tumorigenesis. It prevents cell transformation, but on the other hand, autophagy enables existing cancer cells to adapt to harmful conditions and increased glucose demand, supports maintaining of cellular metabolism and accelerates tumor growth. Among others, it refers to Ras-transformed cells. Recent research unveiled BNIP3 protein as one of the key players involved in autophagy. Although BNIP3 is classified as proapoptotic member of BH3-only subfamily, its proapoptotic activity is questionable. However, BNIP3 demonstrates ability to induce or stimulate autophagy and its specific variant – mitophagy. This paper aims to summarize the existing body of knowledge related to the role of BNIP3 in autophagy, as well as the importance of this process in tumorigenesis. In particular, we emphasize the relation between autophagy and BNIP3 expression induced by Ras oncogene.

  12. Remifentanil induces autophagy and prevents hydrogen peroxide-induced apoptosis in Cos-7 cells.

    Science.gov (United States)

    Yoon, Ji-Young; Baek, Chul-Woo; Woo, Mi-Na; Kim, Eun-Jung; Yoon, Ji-Uk; Park, Chang-Hoon

    2016-09-01

    This study investigated the effect of remifentanil pretreatment on Cos-7 cells exposed to oxidative stress, and the influence of remifentanil on intracellular autophagy and apoptotic cell death. Cells were divided into 4 groups: (1) Control: non-pretreated cells were incubated in normoxia (5% CO 2 , 21% O 2 , and 74% N 2 ). (2) H 2 O 2 : non-pretreated cells were exposed to H 2 O 2 for 24 h. (3) RPC+H 2 O 2 : cells pretreated with remifentanil were exposed to H 2 O 2 for 24 h. (4) 3-MA+RPC+H 2 O 2 : cells pretreated with 3-Methyladenine (3-MA) and remifentanil were exposed to H 2 O 2 for 24 h. We determined the cell viability of each group using an MTT assay. Hoechst staining and FACS analysis of Cos-7 cells were performed to observe the effect of remifentanil on apoptosis. Autophagy activation was determined by fluorescence microscopy, MDC staining, and AO staining. The expression of autophagy-related proteins was observed using western blotting. Remifentanil pretreatment increased the viability of Cos-7 cells exposed to oxidative stress. Hoechst staining and FACS analysis revealed that oxidative stress-dependent apoptosis was suppressed by the pretreatment. Additionally, fluorescence microscopy showed that remifentanil pretreatment led to autophagy-induction in Cos-7 cells, and the expression of autophagy-related proteins was increased in the RPC+H 2 O 2 group. The study showed that remifentanil pretreatment stimulated autophagy and increased viability in an oxidative stress model of Cos-7 cells. Therefore, we suggest that apoptosis was activated upon oxidative stress, and remifentanil preconditioning increased the survival rate of the cells by activating autophagy.

  13. A genetic screen for modifiers of Drosophila caspase Dcp-1 reveals caspase involvement in autophagy and novel caspase-related genes

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    Ahnn Joohong

    2010-01-01

    Full Text Available Abstract Background Caspases are cysteine proteases with essential functions in the apoptotic pathway; their proteolytic activity toward various substrates is associated with the morphological changes of cells. Recent reports have described non-apoptotic functions of caspases, including autophagy. In this report, we searched for novel modifiers of the phenotype of Dcp-1 gain-of-function (GF animals by screening promoter element- inserted Drosophila melanogaster lines (EP lines. Results We screened ~15,000 EP lines and identified 72 Dcp-1-interacting genes that were classified into 10 groups based on their functions and pathways: 4 apoptosis signaling genes, 10 autophagy genes, 5 insulin/IGF and TOR signaling pathway genes, 6 MAP kinase and JNK signaling pathway genes, 4 ecdysone signaling genes, 6 ubiquitination genes, 11 various developmental signaling genes, 12 transcription factors, 3 translation factors, and 11 other unclassified genes including 5 functionally undefined genes. Among them, insulin/IGF and TOR signaling pathway, MAP kinase and JNK signaling pathway, and ecdysone signaling are known to be involved in autophagy. Together with the identification of autophagy genes, the results of our screen suggest that autophagy counteracts Dcp-1-induced apoptosis. Consistent with this idea, we show that expression of eGFP-Atg5 rescued the eye phenotype caused by Dcp-1 GF. Paradoxically, we found that over-expression of full-length Dcp-1 induced autophagy, as Atg8b-GFP, an indicator of autophagy, was increased in the eye imaginal discs and in the S2 cell line. Taken together, these data suggest that autophagy suppresses Dcp-1-mediated apoptotic cell death, whereas Dcp-1 positively regulates autophagy, possibly through feedback regulation. Conclusions We identified a number of Dcp-1 modifiers that genetically interact with Dcp-1-induced cell death. Our results showing that Dcp-1 and autophagy-related genes influence each other will aid future

  14. Important clinical and laboratory correlates of glomerular filtration ...

    African Journals Online (AJOL)

    Background: Renal impairment is routinely assessed using the estimated glomerular filtration rate (eGFR) and it may be helpful to obtain certain clinical or laboratory markers, which show relationship with glomerular filtration rate (GFR) in sickle cell disease (SCD). Aim: To assess the relationship between important clinical ...

  15. Glomerular disease and acute kidney injury in Sudan ...

    African Journals Online (AJOL)

    Age at presentation but not baseline renal function by estimated glomerular filtration rate (eGFR), was associated with the likelihood of having residual chronic kidney disease following an episode of AKI. Conclusions. The data suggested differences in the pattern of intrinsic renal/glomerular disease leading to AKI to those ...

  16. Autophagy. A strategy for cell survival

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    Mónica A. Costas

    2017-08-01

    Full Text Available Autophagy is a process of recycling parts of the cell. As described in this review, it occurs naturally in order to preserve cells from the accumulation of toxins, damaged molecules and organelles, and to allow processes of tissue development and differentiation. In the course of autophagy, the processing of the substrates to be recycled generates ATP, thus providing an alternative source of energy in stress situations. In this sense, under hostile conditions such as hypoxia or lack of nutrients, the autophagy process can be exacerbated leading to cell death. Some alterations in its functioning may involve the development of various pathologies, including liver damage, cancer and neurodegenerative diseases

  17. 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.

  18. Autophagy as an emerging therapy target for ovarian carcinoma

    Science.gov (United States)

    Zhan, Lei; Zhang, Yu; Wang, Wenyan; Song, Enxue; Fan, Yijun; Li, Jun; Wei, Bing

    2016-01-01

    Autophagy is a conserved cellular self-digestion pathway for maintenance of homeostasis under basal and stressed conditions. Autophagy plays pivotal roles in the pathogenesis of many diseases, such as aging-related diseases, autoimmune diseases, cardiovascular diseases, and cancers. Of special note is that accumulating data suggest an intimate relationship between autophagy and ovarian carcinoma. Autophagy is well identified to act as either as a tumor-suppressor or as a tumor-promoter in ovarian carcinoma. The exact function of autophagy in ovarian carcinoma is highly dependent on the circumstances of cancer including hypoxic, nutrient-deficient, chemotherapy and so on. However, the mechanism underlying autophagy associated with ovarian carcinoma remains elusive, the precise role of autophagy in ovarian carcinoma also remains undetermined. In this review, we tried to sum up and discuss recent research achievements of autophagy in ovarian cancer. Moreover, waves of novel therapies ways for ovarian carcinoma based on the functions of autophagy were collected. PMID:27825125

  19. Lipopolysaccharide (LPS)-Induced Autophagy Is Responsible for Enhanced Osteoclastogenesis.

    Science.gov (United States)

    Sul, Ok-Joo; Park, Hyun-Jung; Son, Ho-Jung; Choi, Hye-Seon

    2017-11-30

    We hypothesized that inflammation affects number and activity of osteoclasts (OCs) via enhancing autophagy. Lipopolysaccharide (LPS) induced autophagy, osteoclastogenesis, and cytoplasmic reactive oxygen species (ROS) in bone marrow-derived macrophages that were pre-stimulated with receptor activator of nuclear factor-κB ligand. An autophagy inhibitor, 3-methyladenine (3-MA) decreased LPS-induced OC formation and bone resorption, indicating that autophagy is responsible for increasing number and activity of OCs upon LPS stimulus. Knockdown of autophagy-related protein 7 attenuated the effect of LPS on OC-specific genes, supporting a role of LPS as an autophagy inducer in OC. Removal of ROS decreased LPS-induced OC formation as well as autophagy. However, 3-MA did not affect LPS-induced ROS levels, suggesting that ROS act upstream of phosphatidylinositol-4,5-bisphosphate 3-kinase in LPS-induced autophagy. Our results suggest the possible use of autophagy inhibitors targeting OCs to reduce inflammatory bone loss.

  20. Impact of age on glomerular filtration estimates.

    Science.gov (United States)

    Douville, Pierre; Martel, Ariane R; Talbot, Jean; Desmeules, Simon; Langlois, Serge; Agharazii, Mohsen

    2009-01-01

    Glomerular filtration decreases progressively with age in adults. Predictive equation should have proper modelling to adequately account for normal senescence. Corrected 24-h creatinine clearances (CCLs) were measured in a cohort of 773 outpatients from 18 to 90 years old. Multiple linear regression was used to model the effect of age on glomerular filtration. Comparisons were made with the simplified MDRD and the MAYO equations. Impact of the derived equation was tested in a second cohort of 7551 patients with normal serum creatinine. While all equations show declining function with age, our results suggest that the GFR reduction is progressive after the age of 30 and continue to decline steadily after the age of 60. This leads to a convex curve in the multiple regression analysis that is best fitted by an equation including the quadratic term (age(2)). In contrast, the MDRD equation produces a faster decrease in early adulthood and a flatter curve after the age of 60 while the MAYO equation produces a more linear effect. MDRD results in the normal range are lower than those estimated by the MAYO equation. These equations, as applied on an independent cohort of 7551 normal outpatients from 18 to 102 years, produce different profile of evolution of GFR with age. Inclusion of a quadratic term for age in the formula estimating GFR results in better modelling of the natural decline of renal function associated with ageing. Furthermore, as GFR steadily declines after the age of 30, a single cut-off value of GFR normality for all ages leads to underdiagnosis of young adults and over diagnosis of elderly individuals. Guidelines should take into account the observed reduction of kidney function with age in normal population for optimal evaluation of eGFR.

  1. 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.

  2. Autophagy: More Than a Nonselective Pathway

    Directory of Open Access Journals (Sweden)

    Fulvio Reggiori

    2012-01-01

    Full Text Available Autophagy is a catabolic pathway conserved among eukaryotes that allows cells to rapidly eliminate large unwanted structures such as aberrant protein aggregates, superfluous or damaged organelles, and invading pathogens. The hallmark of this transport pathway is the sequestration of the cargoes that have to be degraded in the lysosomes by double-membrane vesicles called autophagosomes. The key actors mediating the biogenesis of these carriers are the autophagy-related genes (ATGs. For a long time, it was assumed that autophagy is a bulk process. Recent studies, however, have highlighted the capacity of this pathway to exclusively eliminate specific structures and thus better fulfil the catabolic necessities of the cell. We are just starting to unveil the regulation and mechanism of these selective types of autophagy, but what it is already clearly emerging is that structures targeted to destruction are accurately enwrapped by autophagosomes through the action of specific receptors and adaptors. In this paper, we will briefly discuss the impact that the selective types of autophagy have had on our understanding of autophagy.

  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. Kinases Involved in Both Autophagy and Mitosis

    Directory of Open Access Journals (Sweden)

    Zhiyuan Li

    2017-08-01

    Full Text Available Both mitosis and autophagy are highly regulated dynamic cellular processes and involve various phosphorylation events catalysed by kinases, which play vital roles in almost all physiological and pathological conditions. Mitosis is a key event during the cell cycle, in which the cell divides into two daughter cells. Autophagy is a process in which the cell digests its own cellular contents. Although autophagy regulation has mainly been studied in asynchronous cells, increasing evidence indicates that autophagy is in fact tightly regulated in mitosis. Here in this review, we will discuss kinases that were originally identified to be involved in only one of either mitosis or autophagy, but were later found to participate in both processes, such as CDKs (cyclin-dependent kinases, Aurora kinases, PLK-1 (polo-like kinase 1, BUB1 (budding uninhibited by benzimidazoles 1, MAPKs (mitogen-activated protein kinases, mTORC1 (mechanistic target of rapamycin complex 1, AMPK (AMP-activated protein kinase, PI3K (phosphoinositide-3 kinase and protein kinase B (AKT. By focusing on kinases involved in both autophagy and mitosis, we will get a more comprehensive understanding about the reciprocal regulation between the two key cellular events, which will also shed light on their related therapeutic investigations.

  5. Dynamics of intrarenal pressures and glomerular filtration rate after acetazolamide

    DEFF Research Database (Denmark)

    Leyssac, P P; Karlsen, F M; Skøtt, O

    1991-01-01

    The dynamics of intrarenal pressures, early distal tubular fluid conductivity (EDC), and renal flood flow (RBF) were studied in rats given acetazolamide (ACZ), an inhibitor of proximal reabsorption. Glomerular filtration rate (GFR) and end-proximal flow were estimated by clearances of 51Cr......-EDTA and lithium. Proximal tubular pressure (Pprox) increased initially by 1.7 +/- 0.1 mmHg after ACZ, causing a decrease in the hydrostatic pressure difference across the glomerular membrane (delta P). EDC increased, and then RBF, glomerular capillary pressure (Pgc), Pprox, and star vessel pressures (Psv) dropped...

  6. Apicomplexan autophagy and modulation of autophagy in parasite-infected host cells

    Directory of Open Access Journals (Sweden)

    Perle Laté de Laté

    2017-02-01

    Full Text Available Apicomplexan parasites are responsible for a number of important human pathologies. Obviously, as Eukaryotes they share a number of cellular features and pathways with their respective host cells. One of them is autophagy, a process involved in the degradation of the cell's own components. These intracellular parasites nonetheless seem to present a number of original features compared to their very evolutionarily distant host cells. In mammals and other metazoans, autophagy has been identified as an important contributor to the defence against microbial pathogens. Thus, host autophagy also likely plays a key role in the control of apicomplexan parasites, although its potential manipulation and subversion by intracellular parasites creates a complex interplay in the regulation of host and parasite autophagy. In this mini-review, we summarise current knowledge on autophagy in both parasites and their host cells, in the context of infection by three Apicomplexa: Plasmodium, Toxoplasma, and Theileria.

  7. Starvation Promotes Autophagy-Associated Maturation of the Ovary in the Giant Freshwater Prawn,Macrobrachium rosenbergii.

    Science.gov (United States)

    Kankuan, Wilairat; Wanichanon, Chaitip; Titone, Rossella; Engsusophon, Attakorn; Sumpownon, Chanudporn; Suphamungmee, Worawit; Morani, Federica; Masini, Matilde; Novelli, Michela; Isidoro, Ciro; Sobhon, Prasert

    2017-01-01

    Limitation of food availability (starvation) is known to influence the reproductive ability of animals. Autophagy is a lysosomal driven degradation process that protects the cell under metabolic stress conditions, such as during nutrient shortage. Whether, and how starvation-induced autophagy impacts on the maturation and function of reproductive organs in animals are still open questions. In this study, we have investigated the effects of starvation on histological and cellular changes that may be associated with autophagy in the ovary of the giant freshwater prawn, Macrobachium rosenbergii . To this end, the female prawns were daily fed (controls) or unfed (starvation condition) for up to 12 days, and the ovary tissue was analyzed at different time-points. Starvation triggered ovarian maturation, and concomitantly increased the expression of autophagy markers in vitellogenic oocytes. The immunoreactivities for autophagy markers, including Beclin1, LC3-II, and Lamp1, were enhanced in the late oocytes within the mature ovaries, especially at the vitellogenic stages. These markers co-localized with vitellin in the yolk granules within the oocytes, suggesting that autophagy induced by starvation could drive vitellin utilization, thus promoting ovarian maturation.

  8. Autophagy as a target for cancer therapy: new developments

    International Nuclear Information System (INIS)

    Carew, Jennifer S; Kelly, Kevin R; Nawrocki, Steffan T

    2012-01-01

    Autophagy is an evolutionarily conserved lysosomal degradation pathway that eliminates cytosolic proteins, macromolecules, organelles, and protein aggregates. Activation of autophagy may function as a tumor suppressor by degrading defective organelles and other cellular components. However, this pathway may also be exploited by cancer cells to generate nutrients and energy during periods of starvation, hypoxia, and stress induced by chemotherapy. Therefore, induction of autophagy has emerged as a drug resistance mechanism that promotes cancer cell survival via self-digestion. Numerous preclinical studies have demonstrated that inhibition of autophagy enhances the activity of a broad array of anticancer agents. Thus, targeting autophagy may be a global anticancer strategy that may improve the efficacy of many standard of care agents. These results have led to multiple clinical trials to evaluate autophagy inhibition in combination with conventional chemotherapy. In this review, we summarize the anticancer agents that have been reported to modulate autophagy and discuss new developments in autophagy inhibition as an anticancer strategy

  9. 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...

  10. 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.

    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

  11. Normalisation of glomerular filtration rate measurements

    International Nuclear Information System (INIS)

    White, A.J.; Strydom, W.J.

    1991-01-01

    The result of a glomerular filtration rate (GFR) measurement on a particular patient is of limited use to the referring physician since normal GFR values vary widely with the patient's age and build, etc. To overcome this problem, it is usual to normalise the measured GFR by dividing it by the patient's surface area and multiplying the result by the surface area of a 'standard' man. This transforms the measurment onto a scale which applies to all patients, young and old, large and small, where normal values fall within a well-defined range and where the degree of renal impairment can be quantified. We have examined the generally accepted surface area (SA) and the less well-known extracellular volume (ECV) normalisation methods of GFR measurements in a series of 110 patients. The results show that both methods produce essentially the same result; however, ECV normalisation is theoretically more correct, can be found directly without the patient's ECV being measured and does not require the use of empirical formulae. Mathematical justification for ECV normalisation is presented, and a proposed distribution pattern for the normalised measurement is introduced. A simple mathematical model shows that accurate GFR measurements can be made in the presence of an enlarged ECV, but normalisation of these will produce misleading low values. (orig.)

  12. Glomerular basement membrane lipidosis in Alagille syndrome.

    Science.gov (United States)

    Davis, Jessica; Griffiths, Ryan; Larkin, Kay; Rozansky, David; Troxell, Megan

    2010-06-01

    Alagille syndrome is characterized by a paucity of interlobular bile ducts with chronic cholestasis, cardiac, skeletal, and eye abnormalities and is associated predominantly with JAG1 mutations. Various renal abnormalities have been sporadically described. The classic renal histopathology described in Alagille syndrome is mesangiolipidosis, with lipid deposits predominately confined to the mesangium and minimal deposition within the glomerular basement membrane (GBM). We report a 5-year-old girl with Alagille syndrome who presented with persistent subnephrotic proteinuria and renal tubular acidosis. A renal biopsy showed GBM irregularities (mimicking membranous glomerulonephritis), mesangial sclerosis, and focal segmental glomerulosclerosis (FSGS) on light microscopy. Electron microscopy revealed few lipid inclusions within the mesangium but extensive inclusions along the GBM. These findings are mostly consistent with those reported previously in Alagille syndrome. However, the histologic distribution of lipid vacuoles is seemingly reversed in this patient and is uniquely accompanied by FSGS, emphasizing the spectrum of renal histopathology seen in Alagille syndrome. The proteinuria observed in this patient is likely attributed to significant GBM lipid deposition, which over time may contribute to the development of FSGS.

  13. Estimating Glomerular Filtration Rate in Older People

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    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 defici...

  15. Progress and controversies in unraveling the glomerular filtration mechanism.

    Science.gov (United States)

    Saritas, Turgay; Kuppe, Christoph; Moeller, Marcus J

    2015-05-01

    At first sight, the glomerular filter appears like a problem that should be easily solved. The majority of researchers view the filter like an impermeable wall perforated by specialized and size-selective pores (pore model). However, the fact that this model is in conflict with many of the experimental findings suggests that it may not yet be complete. In the more recent electrokinetic model, we have proposed including electrical effects (streaming potentials). The present review investigates how this can provide a relatively simple mechanistic explanation for the great majority of the so far unexplained characteristics of the filter, for example why the filter never clogs. Understanding how the glomerular filter functions is a prerequisite to investigate the pathogenesis of proteinuric glomerular diseases and the link between glomerular proteinuria and cardiovascular disease.

  16. Rapid induction of glomerular lipidosis in APA hamsters by streptozotocin.

    Science.gov (United States)

    Han, J. S.; Sugawara, Y.; Doi, K.

    1992-01-01

    The pathology of male Syrian hamsters of APA strain which were injected intraperitoneally with 40 mg/kg body weight of streptozotocin (SZ) at 2 months of age was examined. It showed long-lasting prominent hyperglycaemia and hyperlipidaemia with glucosuria and the development of glomerular lipidosis from 1 month after SZ-injection (1 MAI). Glomerular lesions were restricted to the juxtamedullary cortex at 1 MAI and then extended to the subcapsular cortex. At 3 MAI, glomerular lesions were characterized by focal segmental glomerulosclerosis showing segmental expansion of the mesangial area due to an increase of basement membrane-like material and mesangial cells with lipid droplets and foam cells. SZ-induced diabetic APA hamsters will be a useful model for the investigation of glomerular lipidosis and focal segmental glomerulosclerosis. Images Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:1533531

  17. MicroRNA-125a Inhibits Autophagy Activation and Antimicrobial Responses during Mycobacterial Infection.

    Science.gov (United States)

    Kim, Jin Kyung; Yuk, Jae-Min; Kim, Soo Yeon; Kim, Tae Sung; Jin, Hyo Sun; Yang, Chul-Su; Jo, Eun-Kyeong

    2015-06-01

    MicroRNAs (miRNAs) are small noncoding nucleotides that play critical roles in the regulation of diverse biological functions, including the response of host immune cells. Autophagy plays a key role in activating the antimicrobial host defense against Mycobacterium tuberculosis. Although the pathways associated with autophagy must be tightly regulated at a posttranscriptional level, the contribution of miRNAs and whether they specifically influence the activation of macrophage autophagy during M. tuberculosis infection are largely unknown. In this study, we demonstrate that M. tuberculosis infection of macrophages leads to increased expression of miRNA-125a-3p (miR-125a), which targets UV radiation resistance-associated gene (UVRAG), to inhibit autophagy activation and antimicrobial responses to M. tuberculosis. Forced expression of miR-125a significantly blocked M. tuberculosis-induced activation of autophagy and phagosomal maturation in macrophages, and inhibitors of miR-125a counteracted these effects. Both TLR2 and MyD88 were required for biogenesis of miR-125a during M. tuberculosis infection. Notably, activation of the AMP-activated protein kinase significantly inhibited the expression of miR-125a in M. tuberculosis-infected macrophages. Moreover, either overexpression of miR-125a or silencing of UVRAG significantly attenuated the antimicrobial effects of macrophages against M. tuberculosis. Taken together, these data indicate that miR-125a regulates the innate host defense by inhibiting the activation of autophagy and antimicrobial effects against M. tuberculosis through targeting UVRAG. Copyright © 2015 by The American Association of Immunologists, Inc.

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

    Indian Academy of Sciences (India)

    2012-01-08

    Jan 8, 2012 ... Nonetheless, compelling data also reveal an unfavorable function of autophagy in facilitating the production of intracellular Aβ. ..... Effect on autophagy. Mode of action in autophagic regulation. References. Lithium. IMPase inhibitor. Activator of autophagy. Reduces inositol and IP3 levels. Sarkar et al. 2005.

  19. 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...

  20. miR-184 and miR-150 promote renal glomerular mesangial cell aging by targeting Rab1a and Rab31.

    Science.gov (United States)

    Liu, Xiujuan; Fu, Bo; Chen, Dapeng; Hong, Quan; Cui, Jing; Li, Jin; Bai, Xueyuan; Chen, Xiangmei

    2015-08-15

    The molecular mechanism of kidney aging is not well understood, but the abnormal expression of miRNAs with aging is considered to be an important contributor. miR-184 and miR-150 were screened using a miRNA microarray and qRT-PCR and found to be significantly upregulated in 24-month-old rats. Rat renal primary glomerular mesangial cells (GMCs) were isolated from 3-month and 24-month-old rats for the in vitro analysis of the roles of miR-184 and miR-150 in kidney aging. Bioinformatics analyses suggested that Rab1a and Rab31, which are associated with cell autophagy, were targeted by both miR-184 and miR-150. miR-184 and miR-150 were increased significantly in aging GMCs versus young cells, while Rab1a and Rab31 were significantly lower in aging cells. Furthermore, dual luciferase reporter assays revealed that miR-184 and miR-150 bound to the 3'-UTR of Rab1a and Rab31 mRNAs. Transfection of miR-184 and miR-150 mimics into young GMCs suppressed the expression of Rab1a and Rab31. Transfected cells showed lower autophagy activities and higher levels of cellular oxidative products, leading to the aging of young GMCs. However, miR-184 and miR-150 inhibitors promoted autophagy and reduced oxidative damage by upregulating Rab1a and Rab31 in old GMCs. In conclusion, miR-184 and miR-150 inhibited autophagy, promoting GMC aging. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Antioxidant Supplement Inhibits Skeletal Muscle Constitutive Autophagy rather than Fasting-Induced Autophagy in Mice

    Directory of Open Access Journals (Sweden)

    Zhengtang Qi

    2014-01-01

    Full Text Available In this study, we tested the hypothesis that NAC administration leads to reduced oxidative stress and thus to decreased expression of autophagy markers in young mice. Our results reveal that NAC administration results in reduced muscle mRNA levels of several autophagy markers, including Beclin-1, Atg7, LC3, Atg9, and LAMP2. However, NAC supplement fails to block the activation of skeletal muscle autophagy in response to fasting, because fasting significantly increases the mRNA level of several autophagy markers and LC3 lipidation. We further examined the effects of NAC administration on mitochondrial antioxidant capacity in fed and 24-hour fasted mice. Our results clearly show that NAC administration depresses the expression of manganese superoxide dismutase (MnSOD and TP53-induced glycolysis and apoptosis regulator (TIGAR, both of which play a predominant antioxidant role in mitochondria by reducing ROS level. In addition, we found no beneficial effect of NAC supplement on muscle mass but it can protect from muscle loss in response to fasting. Collectively, our findings indicate that ROS is required for skeletal muscle constitutive autophagy, rather than starvation-induced autophagy, and that antioxidant NAC inhibits constitutive autophagy by the regulation of mitochondrial ROS production and antioxidant capacity.

  3. 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.

  4. Targeting Autophagy in ALK-Associated Cancers

    Directory of Open Access Journals (Sweden)

    Julie Frentzel

    2017-11-01

    Full Text Available Autophagy is an evolutionarily conserved catabolic process, which is used by the cells for cytoplasmic quality control. This process is induced following different kinds of stresses e.g., metabolic, environmental, or therapeutic, and acts, in this framework, as a cell survival mechanism. However, under certain circumstances, autophagy has been associated with cell death. This duality has been extensively reported in solid and hematological cancers, and has been observed during both tumor development and cancer therapy. As autophagy plays a critical role at the crossroads between cell survival and cell death, its involvement and therapeutic modulation (either activation or inhibition are currently intensively studied in cancer biology, to improve treatments and patient outcomes. Over the last few years, studies have demonstrated the occurrence of autophagy in different Anaplastic Lymphoma Kinase (ALK-associated cancers, notably ALK-positive anaplastic large cell lymphoma (ALCL, non-small cell lung carcinoma (NSCLC, Neuroblastoma (NB, and Rhabdomyosarcoma (RMS. In this review, we will first briefly describe the autophagic process and how it can lead to opposite outcomes in anti-cancer therapies, and we will then focus on what is currently known regarding autophagy in ALK-associated cancers.

  5. 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.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

  6. Ubiquitin-coated nanodiamonds bind to autophagy receptors for entry into the selective autophagy pathway.

    Science.gov (United States)

    Liu, Kuang-Kai; Qiu, Wei-Ru; Naveen Raj, Emmanuel; Liu, Huei-Fang; Huang, Hou-Syun; Lin, Yu-Wei; Chang, Chien-Jen; Chen, Ting-Hua; Chen, Chinpiao; Chang, Huan-Cheng; Hwang, Jenn-Kang; Chao, Jui-I

    2017-01-02

    Selective macroautophagy/autophagy plays a pivotal role in the processing of foreign pathogens and cellular components to maintain homeostasis in human cells. To date, numerous studies have demonstrated the uptake of nanoparticles by cells, but their intracellular processing through selective autophagy remains unclear. Here we show that carbon-based nanodiamonds (NDs) coated with ubiquitin (Ub) bind to autophagy receptors (SQSTM1 [sequestosome 1], OPTN [optineurin], and CALCOCO2/NDP52 [calcium binding and coiled-coil domain 2]) and are then linked to MAP1LC3/LC3 (microtubule-associated protein 1 light chain 3) for entry into the selective autophagy pathway. NDs are ultimately delivered to lysosomes. Ectopically expressed SQSTM1-green fluorescence protein (GFP) could bind to the Ub-coated NDs. By contrast, the Ub-associated domain mutant of SQSTM1 (ΔUBA)-GFP did not bind to the Ub-coated NDs. Chloroquine, an autophagy inhibitor, prevented the ND-containing autophagosomes from fusing with lysosomes. Furthermore, autophagy receptors OPTN and CALCOCO2/NDP52, involved in the processing of bacteria, were found to be involved in the selective autophagy of NDs. However, ND particles located in the lysosomes of cells did not induce mitotic blockage, senescence, or cell death. Single ND clusters in the lysosomes of cells were observed in the xenografted human lung tumors of nude mice. This study demonstrated for the first time that Ub-coated nanoparticles bind to autophagy receptors for entry into the selective autophagy pathway, facilitating their delivery to lysosomes.

  7. Renal extramedullary hematopoiesis: interstitial and glomerular pathology.

    Science.gov (United States)

    Alexander, Mariam P; Nasr, Samih H; Kurtin, Paul J; Casey, Edward T; Hernandez, Loren P Herrera; Fidler, Mary E; Sethi, Sanjeev; Cornell, Lynn D

    2015-12-01

    Renal extramedullary hematopoiesis is rarely recognized in the antemortem setting. We identified 14 patients with renal extramedullary hematopoiesis on antemortem specimens from 1994 to 2015. The mean age was 68 years (range 47-87 years); males predominated (M:F=9:5). All presented with renal insufficiency, including five (36%) with acute kidney injury. The mean serum creatinine at biopsy was 2.9 mg/dl (range 1.2-7.3 mg/dl). All had proteinuria (mean 7.9 g/24 h; range 0.5-28; n=13), including 9 with ≥3 g/24 h. Renal extramedullary hematopoiesis appeared histologically as an interstitial infiltrate (n=12) and/or a perirenal infiltrate (n=3) or mass-like lesion (n=1). Five were misdiagnosed as interstitial nephritis. Concurrent glomerular disease was prevalent and included fibrillary-like glomerulonephritis (n=3), chronic thrombotic microangiopathy (n=5), focal segmental glomerulosclerosis (n=6), and diabetic glomerulosclerosis (n=2). All patients had an underlying hematologic malignancy: primary myelofibrosis in 9, myeloproliferative neoplasm not otherwise specified in 1, essential thrombocythemia in 1, polycythemia vera in 1, and plasma cell myeloma in 2. Clinical follow-up was available in 12 patients, mean of 29 months (range 4-120 months). In 10 patients for whom treatment history could be obtained, 9 were treated with chemotherapy, and 1 was treated with steroids. The mean creatinine at last follow-up was 2 mg/dl (range 1.2-3.9 mg/dl) (n=9). Ten patients died in the follow-up period from their underlying hematological disease and had persistent renal disease. The two remaining patients had persistent chronic kidney disease. Renal extramedullary hematopoiesis should be considered in the differential diagnosis of interstitial infiltrates, particularly in the presence of a glomerulopathy and a hematologic malignancy.

  8. Lipophagy: Connecting Autophagy and Lipid Metabolism

    Directory of Open Access Journals (Sweden)

    Rajat Singh

    2012-01-01

    Full Text Available Lipid droplets (LDs, initially considered “inert” lipid deposits, have gained during the last decade the classification of cytosolic organelles due to their defined composition and the multiplicity of specific cellular functions in which they are involved. The classification of LD as organelles brings along the need for their regulated turnover and recent findings support the direct contribution of autophagy to this turnover through a process now described as lipophagy. This paper focuses on the characteristics of this new type of selective autophagy and the cellular consequences of the mobilization of intracellular lipids through this process. Lipophagy impacts the cellular energetic balance directly, through lipid breakdown and, indirectly, by regulating food intake. Defective lipophagy has been already linked to important metabolic disorders such as fatty liver, obesity and atherosclerosis, and the age-dependent decrease in autophagy could underline the basis for the metabolic syndrome of aging.

  9. Autophagy in health and disease: focus on the cardiovascular system.

    Science.gov (United States)

    Mialet-Perez, Jeanne; Vindis, Cécile

    2017-12-12

    Autophagy is a highly conserved mechanism of lysosome-mediated protein and organelle degradation that plays a crucial role in maintaining cellular homeostasis. In the last few years, specific functions for autophagy have been identified in many tissues and organs. In the cardiovascular system, autophagy appears to be essential to heart and vessel homeostasis and function; however defective or excessive autophagy activity seems to contribute to major cardiovascular disorders including heart failure (HF) or atherosclerosis. Here, we review the current knowledge on the role of cardiovascular autophagy in physiological and pathophysiological conditions. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  10. Emerging role of autophagy in kidney function, diseases and aging

    Science.gov (United States)

    Huber, Tobias B.; Edelstein, Charles L.; Hartleben, Björn; Inoki, Ken; Jiang, Man; Koya, Daisuke; Kume, Shinji; Lieberthal, Wilfred; Pallet, Nicolas; Quiroga, Alejandro; Ravichandran, Kameswaran; Susztak, Katalin; Yoshida, Sei; Dong, Zheng

    2012-01-01

    Autophagy is a highly conserved process that degrades cellular long-lived proteins and organelles. Accumulating evidence indicates that autophagy plays a critical role in kidney maintenance, diseases and aging. Ischemic, toxic, immunological, and oxidative insults can cause an induction of autophagy in renal epithelial cells modifying the course of various kidney diseases. This review summarizes recent insights on the role of autophagy in kidney physiology and diseases alluding to possible novel intervention strategies for treating specific kidney disorders by modifying autophagy. PMID:22692002

  11. Myocardial Autophagy after Severe Burn in Rats

    Science.gov (United States)

    Zhang, Qiong; Shi, Xiao-hua; Huang, Yue-sheng

    2012-01-01

    Background Autophagy plays a major role in myocardial ischemia and hypoxia injury. The present study investigated the effects of autophagy on cardiac dysfunction in rats after severe burn. Methods Protein expression of the autophagy markers LC3 and Beclin 1 were determined at 0, 1, 3, 6, and 12 h post-burn in Sprague Dawley rats subjected to 30% total body surface area 3rd degree burns. Autophagic, apoptotic, and oncotic cell death were evaluated in the myocardium at each time point by immunofluorescence. Changes of cardiac function were measured in a Langendorff model of isolated heart at 6 h post-burn, and the autophagic response was measured following activation by Rapamycin and inhibition by 3-methyladenine (3-MA). The angiotensin converting enzyme inhibitor enalaprilat, the angiotensin receptor I blocker losartan, and the reactive oxygen species inhibitor diphenylene iodonium (DPI) were also applied to the ex vivo heart model to examine the roles of these factors in post-burn cardiac function. Results Autophagic cell death was first observed in the myocardium at 3 h post-burn, occurring in 0.008 ± 0.001% of total cardiomyocytes, and continued to increase to a level of 0.022 ± 0.005% by 12 h post-burn. No autophagic cell death was observed in control hearts. Compared with apoptosis, autophagic cell death occurred earlier and in larger quantities. Rapamycin enhanced autophagy and decreased cardiac function in isolated hearts 6 h post-burn, while 3-MA exerted the opposite response. Enalaprilat, losartan, and DPI all inhibited autophagy and enhanced heart function. Conclusion Myocardial autophagy is enhanced in severe burns and autophagic cell death occurred early at 3 h post-burn, which may contribute to post-burn cardiac dysfunction. Angiotensin II and reactive oxygen species may play important roles in this process by regulating cell signaling transduction. PMID:22768082

  12. 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.

  13. Autophagy in breast cancer and its implications for therapy

    Science.gov (United States)

    Jain, Kirti; Paranandi, Krishna S; Sridharan, Savitha; Basu, Alakananda

    2013-01-01

    Autophagy is an evolutionarily conserved process of cellular self-digestion that serves as a mechanism to clear damaged organelles and recycle nutrients. Since autophagy can promote cell survival as well as cell death, it has been linked to different human pathologies, including cancer. Although mono-allelic deletion of autophagy-related gene BECN1 in breast tumors originally indicated a tumor suppressive role for autophagy in breast cancer, the intense research during the last decade suggests a role for autophagy in tumor progression. It is now recognized that tumor cells often utilize autophagy to survive various stresses, such as oncogene-induced transformation, hypoxia, endoplasmic reticulum (ER) stress and extracellular matrix detachment. Induction of autophagy by tumor cells may also contribute to tumor dormancy and resistance to anticancer therapies, thus making autophagy inhibitors promising drug candidates for breast cancer treatment. The scientific endeavors continue to define a precise role for autophagy in breast cancer. In this article, we review the current literature on the role of autophagy during the development and progression of breast cancer, and discuss the potential of autophagy modulators for breast cancer treatment. PMID:23841025

  14. Inhibition of autophagy initiation potentiates chemosensitivity in mesothelioma.

    Science.gov (United States)

    Follo, Carlo; Cheng, Yao; Richards, William G; Bueno, Raphael; Broaddus, Virginia Courtney

    2018-03-01

    The benefits of inhibiting autophagy in cancer are still controversial, with differences in outcome based on the type of tumor, the context and the particular stage of inhibition. Here, we investigated the impact of inhibiting autophagy at different stages on chemosensitivity using 3-dimensional (3D) models of mesothelioma, including ex vivo human tumor fragment spheroids. As shown by LC3B accumulation, we successfully inhibited autophagy using either an early stage ULK1/2 inhibitor (MRT 68921) or a late stage inhibitor (hydroxychloroquine). We found that inhibition of autophagy at the early stage, but not at late stage, potentiated chemosensitivity. This effect was seen only in those spheroids with high autophagy and active initiation at steady state. Inhibition of autophagy alone, at either early or late stage, did not cause cell death, showing that the inhibitors were non-toxic and that mesothelioma did not depend on autophagy at baseline, at least over 24 h. Using ATG13 puncta analysis, we found that autophagy initiation identified tumors that are more chemosensitive at baseline and after autophagy inhibition. Our results highlight a potential role of autophagy initiation in supporting mesothelioma cells during chemotherapy. Our work also highlights the importance of testing the inhibition of different stages in order to uncover the role of autophagy and the potential of its modulation in the treatment of cancer. © 2017 Wiley Periodicals, Inc.

  15. Autophagy: one more Nobel Prize for yeast

    Directory of Open Access Journals (Sweden)

    Andreas Zimmermann

    2016-12-01

    Full Text Available The recent announcement of the 2016 Nobel Prize in Physiology or Medicine, awarded to Yoshinori Ohsumi for the discoveries of mechanisms governing autophagy, underscores the importance of intracellular degradation and recycling. At the same time, it further cements yeast, in which this field decisively developed, as a prolific model organism. Here we provide a quick historical overview that mirrors both the importance of autophagy as a conserved and essential process for cellular life and death as well as the crucial role of yeast in its mechanistic characterization.

  16. Role of autophagy in development and progression of acute pancreatitis

    Directory of Open Access Journals (Sweden)

    YANG Shuli

    2014-08-01

    Full Text Available Acute pancreatitis is considered an autodigestive disorder in which inappropriate activation of trypsinogen to trypsin within pancreatic acinar cells leads to the development of pancreatitis. Autophagy is an evolutionarily preserved degradation process of cytoplasmic cellular constituents, and it is one of the early pathological processes in acute pancreatitis. Autophagic flux is impaired in acute pancreatitis, which mediates the key pathologic responses of this disease. Impaired autophagy, dysfunction of lysosomes, and dysregulation of autophagy suggest a disorder of the endolysosomal pathway in acute pancreatitis. The role of autophagy in acute pancreatitis is discussed from the aspects of autophagic process, autophagy and activation of trypsinogen, impaired autophagy and acute pancreatitis, and defective autophagy promoting inflammation.

  17. Molecular Interactions of Autophagy with the Immune System and Cancer

    Directory of Open Access Journals (Sweden)

    Yunho Jin

    2017-08-01

    Full Text Available Autophagy is a highly conserved catabolic mechanism that mediates the degradation of damaged cellular components by inducing their fusion with lysosomes. This process provides cells with an alternative source of energy for the synthesis of new proteins and the maintenance of metabolic homeostasis in stressful environments. Autophagy protects against cancer by mediating both innate and adaptive immune responses. Innate immune receptors and lymphocytes (T and B are modulated by autophagy, which represent innate and adaptive immune responses, respectively. Numerous studies have demonstrated beneficial roles for autophagy induction as well as its suppression of cancer cells. Autophagy may induce either survival or death depending on the cell/tissue type. Radiation therapy is commonly used to treat cancer by inducing autophagy in human cancer cell lines. Additionally, melatonin appears to affect cancer cell death by regulating programmed cell death. In this review, we summarize the current understanding of autophagy and its regulation in cancer.

  18. 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.

  19. Degradation of AF1Q by chaperone-mediated autophagy

    International Nuclear Information System (INIS)

    Li, Peng; Ji, Min; Lu, Fei; Zhang, Jingru; Li, Huanjie; Cui, Taixing; Li Wang, Xing; Tang, Dongqi; Ji, Chunyan

    2014-01-01

    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

  20. 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.

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

    International Nuclear Information System (INIS)

    Maruyama, Yoko; Sou, Yu-Shin; Kageyama, Shun; Takahashi, Takao; Ueno, Takashi; Tanaka, Keiji; Komatsu, Masaaki; Ichimura, Yoshinobu

    2014-01-01

    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

  2. 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.

  3. Distinct surveillance pathway for immunopathology during acute infection via autophagy and SR-BI

    Science.gov (United States)

    Pfeiler, Susanne; Khandagale, Avinash B.; Magenau, Astrid; Nichols, Maryana; Heijnen, Harry F. G.; Rinninger, Franz; Ziegler, Tilman; Seveau, Stephanie; Schubert, Sören; Zahler, Stefan; Verschoor, Admar; Latz, Eicke; Massberg, Steffen; Gaus, Katharina; Engelmann, Bernd

    2016-01-01

    The mechanisms protecting from immunopathology during acute bacterial infections are incompletely known. We found that in response to apoptotic immune cells and live or dead Listeria monocytogenes scavenger receptor BI (SR-BI), an anti-atherogenic lipid exchange mediator, activated internalization mechanisms with characteristics of macropinocytosis and, assisted by Golgi fragmentation, initiated autophagic responses. This was supported by scavenger receptor-induced local increases in membrane cholesterol concentrations which generated lipid domains particularly in cell extensions and the Golgi. SR-BI was a key driver of beclin-1-dependent autophagy during acute bacterial infection of the liver and spleen. Autophagy regulated tissue infiltration of neutrophils, suppressed accumulation of Ly6C+ (inflammatory) macrophages, and prevented hepatocyte necrosis in the core of infectious foci. Perifocal levels of Ly6C+ macrophages and Ly6C− macrophages were unaffected, indicating predominant regulation of the focus core. SR-BI-triggered autophagy promoted co-elimination of apoptotic immune cells and dead bacteria but barely influenced bacterial sequestration and survival or inflammasome activation, thus exclusively counteracting damage inflicted by immune responses. Hence, SR-BI- and autophagy promote a surveillance pathway that partially responds to products of antimicrobial defenses and selectively prevents immunity-induced damage during acute infection. Our findings suggest that control of infection-associated immunopathology can be based on a unified defense operation. PMID:27694929

  4. Investigation of cadmium-induced alterations in renal glomerular function

    International Nuclear Information System (INIS)

    Long, T.J.

    1982-01-01

    This research was designed to test the hypothesis that certain aspects of cadmium-induced renal dysfunction are the result of glomerular, rather than classic tubular, injury. To determine whether cadmium-induced proteinuria was due to altered glomerular function, cadmium was administered chronically at a concentration of 185 ppm in the drinking water. This protocol resulted in the production of proteinuria which when analyzed by high pressure liquid chromatography and radioimmunoassay was indistinguishable from that occurring in control rats. Glomerular filtration rate, renal blood flow, and filtration fraction were all significantly depressed after 20-30 weeks of exposure. In order to further investigate these alterations in glomerular function, an acute exposure model was developed. It was found that a single i.p. injection of cadmium in mercaptoethanol resulted in the onset of acute renal failure. The clinical picture was characterized by a reduction in glomerular filtrate rate of 50-90% within 24 hours, with partial to total recovery occurring by day 7 post-exposure. Histological evidence indicated that to a large extent the reduction in GFR was due to tubular blockade and/or backleak of filtrate across damaged tubules

  5. Molecular make-up of the glomerular filtration barrier.

    Science.gov (United States)

    Patrakka, Jaakko; Tryggvason, Karl

    2010-05-21

    The glomerular filtration barrier is composed of glomerular endothelial cells, the glomerulus basement membrane and the podocyte cell layer. The filtration barrier is a target of injury in several systemic and renal diseases, and this often leads to progressive renal disease and kidney failure. Therefore, it is essential to understand the molecular biology of the glomerulus. During the last two decades, a lot of new information about molecular components of the glomerulus filtration barrier has been generated. Many of the key discoveries have been obtained through studies on the genetic background of inherited glomerular diseases. These studies have emphasized the role of podocytes in the filtration barrier function. During the last decade, the use of knockout mouse technology has become more available and given important new insights into the functional significance of glomerular components. Large-scale approaches, such as microarray profiling, have also given data about molecules involved in the biology and pathology of the glomerulus. In the coming decade, the use of global expression profiling platforms, transgenic mouse lines, and other in vivo gene delivery methods will rapidly expand our understanding of biology and pathology of the glomerular filtration barrier, and hopefully expose novel target molecules for therapy in progressive renal diseases. 2010 Elsevier Inc. All rights reserved.

  6. Outcome of the acute glomerular injury in proliferative lupus nephritis

    Energy Technology Data Exchange (ETDEWEB)

    Chagnac, A.; Kiberd, B.A.; Farinas, M.C.; Strober, S.; Sibley, R.K.; Hoppe, R.; Myers, B.D. (Stanford Univ. Medical Center, CA (USA))

    1989-09-01

    Treatment with total lymphoid irradiation (TLI) and corticosteroids markedly reduced activity of systemic lupus erythematosis in 10 patients with diffuse proliferative lupus nephritis (DPLN) complicated by a nephrotic syndrome. Physiologic and morphometric techniques were used serially before, and 12 and 36 mo post-TLI to characterize the course of glomerular injury. Judged by a progressive reduction in the density of glomerular cells and immune deposits, glomerular inflammation subsided. A sustained reduction in the fractional clearance of albumin, IgG and uncharged dextrans of radius greater than 50 A, pointed to a parallel improvement in glomerular barrier size-selectivity. Corresponding changes in GFR were modest, however. A trend towards higher GFR at 12 mo was associated with a marked increase in the fraction of glomerular tuft area occupied by patent capillary loops as inflammatory changes receded. A late trend toward declining GFR beyond 12 mo was associated with progressive glomerulosclerosis, which affected 57% of all glomeruli globally by 36 mo post-TLI. Judged by a parallel increase in volume by 59%, remaining, patent glomeruli had undergone a process of adaptive enlargement. We propose that an increasing fraction of glomeruli continues to undergo progressive sclerosis after DPLN has become quiescent, and that the prevailing GFR depends on the extent to which hypertrophied remnant glomeruli can compensate for the ensuing loss of filtration surface area.

  7. Emerging connections between RNA and autophagy

    DEFF Research Database (Denmark)

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

    2017-01-01

    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...

  8. Autophagy: Regulation and role in disease

    NARCIS (Netherlands)

    Meijer, Alfred J.; Codogno, Patrice

    2009-01-01

    Autophagy, a lysosomal process involved in the maintenance of cellular homeostasis, is responsible for the turnover of long-lived proteins and organelles that are either damaged or functionally redundant. The process is tightly controlled by the insulin-amino acid-mammalian target of the

  9. 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.

  10. Autophagy in the light of sphingolipid metabolism

    DEFF Research Database (Denmark)

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

    2015-01-01

    moieties of biomembranes, lipids including sphingolipids are increasingly being recognized as central regulators of a number of important cellular processes, including autophagy. In the present review we describe how sphingolipids, with special emphasis on ceramides and sphingosine-1-phosphate, can act...

  11. Optical, real-time monitoring of the glomerular filtration rate

    Science.gov (United States)

    Rabito, Carlos A.; Chen, Yang; Schomacker, Kevin T.; Modell, Mark D.

    2005-10-01

    An easy and accurate assessment of the renal function is a critical requirement for detecting the initial functional decline of the kidney induced by acute or chronic renal disease. A method for measuring the glomerular filtration rate is developed with the accuracy of clearance techniques and the convenience of plasma creatinine. The renal function is measured in rats as the rate of clearance determined from time-resolved transcutaneous fluorescence measurements of a new fluorescent glomerular filtration agent. The agent has a large dose-safety coefficient and the same space distribution and clearance characteristics as iothalamate. This new approach is a convenient and accurate way to perform real-time measurements of the glomerular filtration rate to detect early kidney disease before the renal function becomes severely and irreversibly compromised.

  12. Glomerular basement membrane composition and the filtration barrier.

    Science.gov (United States)

    Miner, Jeffrey H

    2011-09-01

    The glomerular basement membrane (GBM) is an especially thick basement membrane that contributes importantly to the kidney's filtration barrier. The GBM derives from the fusion of separate podocyte and endothelial cell basement membranes during glomerulogenesis and consists primarily of laminin-521 (α5β2γ1), collagen α3α4α5(IV), nidogens-1 and -2, and agrin. Of these nine proteins, mutations in the genes encoding four of them (LAMB2, COL4A3, COL4A4, and COL4A5) cause glomerular disease in humans as well as in mice. Furthermore, mutation of a fifth (Lama5) gene in podocytes in mice causes proteinuria, nephrotic syndrome, and progression to renal failure. These results highlight the importance of the GBM for establishing and maintaining a properly functioning glomerular filtration barrier.

  13. Glomerular hyperfiltration and increased glomerular filtration surface are associated with renal function decline in normo- and microalbuminuric type 2 diabetes.

    Science.gov (United States)

    Moriya, Tatsumi; Tsuchiya, Akiko; Okizaki, Shin-ichiro; Hayashi, Akinori; Tanaka, Keiji; Shichiri, Masayoshi

    2012-03-01

    The prevalence of glomerular hyperfiltration in type 2 diabetic patients varies widely. Here we studied whether glomerular hyperfiltration in diabetic nephropathy in type 2 patients is related to renal structural changes and predicts the functional development of diabetic nephropathy. Thirty normo- or microalbuminuric type 2 diabetic patients having a renal biopsy were followed every 6 months for a mean of 6.2 years. The glomerular filtration rate (GFR) at the time of biopsy, determined by iohexol clearance, correlated with filtration surface per glomerulus, but no other quantitative microscopic morphometric parameter. The filtration surface was positively associated with the decrease in GFR during the first year but not associated in subsequent years following the renal biopsy. The GFR showed a statistically significant linear decrease in 9 of the 30 patients; however, slopes of the regression lines were almost zero in 11 patients. The GFR increased and decreased in a parabolic manner in two patients. Seven of the nine patients with a statistically significant decline in renal function did not show any appreciable worsening of albuminuria, while two patients developed persistent proteinuria. Thus, in renal biopsy-proven normo- or microalbuminuric type 2 diabetic patients, glomerular hyperfiltration is closely associated with an increased glomerular filtration surface. An elevated GFR predicts its subsequent decline, which may occur without worsening of albuminuria.

  14. Role of autophagy in HIV infection and pathogenesis.

    Science.gov (United States)

    Nardacci, R; Ciccosanti, F; Marsella, C; Ippolito, G; Piacentini, M; Fimia, G M

    2017-05-01

    The aim of autophagy is to re-establish homeostasis in response to a variety of stress conditions. By forming double-membrane vesicles, autophagy engulfs damaged or superfluous cytoplasmic material and recycles degradation products for new synthesis or energy production. Of note, the same mechanism is used to capture pathogens and has important implications in both innate and adaptive immunity. To establish a chronic infection, pathogens have therefore evolved multiple mechanisms to evade autophagy-mediated degradation. HIV infection represents one of the best characterized systems in which autophagy is disarmed by a virus using multiple strategies to prevent the sequestration and degradation of its proteins and to establish a chronic infection. HIV alters autophagy at various stages of the process in both infected and bystander cells. In particular, the HIV proteins TAT, NEF and ENV are involved in this regulation by either blocking or stimulating autophagy through direct interaction with autophagy proteins and/or modulation of the mTOR pathway. Although the roles of autophagy during HIV infection are multiple and vary amongst the different cell types, several lines of evidence point to a potential beneficial effect of stimulating autophagy-mediated lysosomal degradation to potentiate the immune response to HIV. Characterization of the molecular mechanisms regulating selective autophagy is expected to be valuable for developing new drugs able to specifically enhance the anti-HIV response. © 2017 The Association for the Publication of the Journal of Internal Medicine.

  15. Impairment of autophagy: From hereditary disorder to drug intoxication

    International Nuclear Information System (INIS)

    Aki, Toshihiko; Funakoshi, Takeshi; Unuma, Kana; Uemura, Koichi

    2013-01-01

    At first, the molecular mechanism of autophagy was unveiled in a unicellular organism Saccharomyces cerevisiae (budding yeast), followed by the discovery that the basic mechanism of autophagy is conserved in multicellular organisms including mammals. Although autophagy was considered to be a non-selective bulk protein degradation system to recycle amino acids during periods of nutrient starvation, it is also believed to be an essential mechanism for the selective elimination of proteins/organelles that are damaged under pathological conditions. Research advances made using autophagy-deficient animals have revealed that impairments of autophagy often underlie the pathogenesis of hereditary disorders such as Danon, Parkinson's, Alzheimer's, and Huntington's diseases, and amyotrophic lateral sclerosis. On the other hand, there are many reports that drugs and toxicants, including arsenic, cadmium, paraquat, methamphetamine, and ethanol, induce autophagy during the development of their toxicity on many organs including heart, brain, lung, kidney, and liver. Although the question as to whether autophagic machinery is involved in the execution of cell death or not remains controversial, the current view of the role of autophagy during cell/tissue injury is that it is an important, often essential, cytoprotective reaction; disturbances in cytoprotective autophagy aggravate cell/tissue injuries. The purpose of this review is to provide (1) a gross summarization of autophagy processes, which are becoming more important in the field of toxicology, and (2) examples of important studies reporting the involvement of perturbations in autophagy in cell/tissue injuries caused by acute as well as chronic intoxication

  16. 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.

  17. Defective regulation of adipose tissue autophagy in obesity.

    Science.gov (United States)

    Nuñez, C E; Rodrigues, V S; Gomes, F S; Moura, R F de; Victorio, S C; Bombassaro, B; Chaim, E A; Pareja, J C; Geloneze, B; Velloso, L A; Araujo, E P

    2013-11-01

    Autophagy is a highly regulated process that has an important role in the control of a wide range of cellular functions, such as organelle recycling, nutrient availability and tissue differentiation. A recent study has shown an increased autophagic activity in the adipose tissue of obese subjects, and a role for autophagy in obesity-associated insulin resistance was proposed. Body mass reduction is the most efficient approach to tackle insulin resistance in over-weight subjects; however, the impact of weight loss in adipose tissue autophagy is unknown. Adipose tissue autophagy was evaluated in mice and humans. First, a mouse model of diet-induced obesity and diabetes was maintained on a 15-day, 40% caloric restriction. At baseline, markers of autophagy were increased in obese mice as compared with lean controls. Upon caloric restriction, autophagy increased in the lean mice, whereas it decreased in the obese mice. The reintroduction of ad libitum feeding was sufficient to rapidly reduce autophagy in the lean mice and increase autophagy in the obese mice. In the second part of the study, autophagy was evaluated in the subcutaneous adipose tissue of nine obese-non-diabetic and six obese-diabetic subjects undergoing bariatric surgery for body mass reduction. Specimens were collected during the surgery and approximately 1 year later. Markers of systemic inflammation, such as tumor necrosis factor-1α, interleukin (IL)-6 and IL-1β were evaluated. As in the mouse model, human obesity was associated with increased autophagy, and body mass reduction led to an attenuation of autophagy in the adipose tissue. Obesity and caloric overfeeding are associated with the defective regulation of autophagy in the adipose tissue. The studies in obese-diabetic subjects undergoing improved metabolic control following calorie restriction suggest that autophagy and inflammation are regulated independently.

  18. Analysis of Autophagy Genes in Microalgae: Chlorella as a Potential Model to Study Mechanism of Autophagy

    Science.gov (United States)

    Jiang, Qiao; Zhao, Li; Dai, Junbiao; Wu, Qingyu

    2012-01-01

    Background Microalgae, with the ability to mitigate CO2 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 photosynthetic

  19. Autophagy contributes to degradation of Hirano bodies.

    Science.gov (United States)

    Kim, Dong-Hwan; Davis, Richard C; Furukawa, Ruth; Fechheimer, Marcus

    2009-01-01

    Hirano bodies are actin-rich inclusions reported most frequently in the hippocampus in association with a variety of conditions including neurodegenerative diseases, and aging. We have developed a model system for formation of Hirano bodies in Dictyostelium and cultured mammalian cells to permit detailed studies of the dynamics of these structures in living cells. Model Hirano bodies are frequently observed in membrane-enclosed vesicles in mammalian cells consistent with a role of autophagy in the degradation of these structures. Clearance of Hirano bodies by an exocytotic process is supported by images from electron microscopy showing extracellular release of Hirano bodies, and observation of Hirano bodies in the culture medium of Dictyostelium and mammalian cells. An autophagosome marker protein Atg8-GFP, was co-localized with model Hirano bodies in wild type Dictyostelium cells, but not in atg5(-) or atg1-1 autophagy mutant strains. Induction of model Hirano bodies in Dictyostelium with a high level expression of 34 kDa DeltaEF1 from the inducible discoidin promoter resulted in larger Hirano bodies and a cessation of cell doubling. The degradation of model Hirano bodies still occurred rapidly in autophagy mutant (atg5(-)) Dictyostelium, suggesting that other mechanisms such as the ubiquitin-mediated proteasome pathway could contribute to the degradation of Hirano bodies. Chemical inhibition of the proteasome pathway with lactacystin, significantly decreased the turnover of Hirano bodies in Dictyostelium providing direct evidence that autophagy and the proteasome can both contribute to degradation of Hirano bodies. Short term treatment of mammalian cells with either lactacystin or 3-methyl adenine results in higher levels of Hirano bodies and a lower level of viable cells in the cultures, supporting the conclusion that both autophagy and the proteasome contribute to degradation of Hirano bodies.

  20. 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.

  1. The kinetics of autophagy in the lung following acute spinal cord injury in rats.

    Science.gov (United States)

    Chu, Ruiliang; Wang, Jiuling; Bi, Yang; Nan, Guoxin

    2018-01-31

    Lung injury is a major cause of respiratory complications following an acute spinal cord injury (ASCI), which are associated with a high mortality rate. Autophagy has been shown to be involved in a variety of lung diseases; however, whether autophagy is activated in the lung following ASCI remains unknown. The objective of this study was to investigate the induction of autophagy in the lung after ASCI. This is an experimental animal study of ASCI investigating kinetics of autophagy in the lung following ASCI. One hundred and forty-four rats (N=144) were divided into two groups: (1) a sham (n=72) and (2) an injury group (n=72). Allen's method was used to induce an injury at the level of the 10th thoracic vertebra. Rats were sacrificed at 6, 12, 24, 48, and 72 hours, 1 week, and 2 weeks after surgery. Lung pathology and apoptosis were assessed to determine the level of damage in the lung. LC3, RAB7, P62, and Beclin 1 were used to detect the induction of autophagy. The study was funded by the Natural Science Foundation of China (NSFC,81272172); National Key Specialty Construction of Clinical Projects of China (#2013-544). The funder of the present study had no capacity to influence the scholarly conduct of the research, interpretation of results, or dissemination of study outcomes. In the injury group, pathologic changes (i.e., pulmonary congestion, hemorrhage, inflammatory exudation, and alveolar collapse) occurred within the lung tissue within 72 hours after ASCI. Apoptosis of the lung cells gradually increased and peaked 72 hours after ASCI. Within 24 hours of ASCI, LC3 expression decreased, recovered, and gradually increased from 24 hours to 72 hours. As RAB7 decreased, P62 increased, and the ratio of RAB7/LC3 significantly decreased. After ASCI, autophagy in the injured lung underwent dynamic changes, as early autophagosome formation decreased and late autophagosomes accumulated; thus, autophagy is in a state of inhibition. Copyright © 2018 Elsevier Inc. All

  2. Propofol protects against oxidative-stress-induced COS-7 cell apoptosis by inducing autophagy.

    Science.gov (United States)

    Yoon, Ji-Young; Baek, Chul-Woo; Kim, Eun-Jung; Park, Bong-Soo; Yu, Su-Bin; Yoon, Ji-Uk; Kim, Eok-Nyun

    2017-03-01

    In oxidative stress, reactive oxygen species (ROS) production contributes to cellular dysfunction and initiates the apoptotic cascade. Autophagy is considered the mechanism that decreases ROS concentration and oxidative damage. Propofol shows antioxidant properties, but the mechanisms underlying the effect of propofol preconditioning (PPC) on oxidative injury remain unclear. Therefore, we investigated whether PPC protects against cell damage from hydrogen peroxide (H 2 O 2 )-induced oxidative stress and influences cellular autophagy. COS-7 cells were randomly divided into the following groups: control, cells were incubated in normoxia (5% CO 2 , 21% O 2 , and 74% N 2 ) for 24 h without propofol; H 2 O 2 , cells were exposed to H 2 O 2 (400 µM) for 2 h; PPC + H 2 O 2 , cells pretreated with propofol were exposed to H 2 O 2 ; and 3-methyladenine (3-MA) + PPC + H 2 O 2 , cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to H 2 O 2 . Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide thiazolyl blue (MTT) reduction. Apoptosis was determined using Hoechst 33342 staining and fluorescence microscopy. The relationship between PPC and autophagy was detected using western blot analysis. Cell viability decreased more significantly in the H 2 O 2 group than in the control group, but it was improved by PPC (100 µM). Pretreatment with propofol effectively decreased H 2 O 2 -induced COS-7 cell apoptosis. However, pretreatment with 3-MA inhibited the protective effect of propofol during apoptosis. Western blot analysis showed that the level of autophagy-related proteins was higher in the PPC + H 2 O 2 group than that in the H 2 O 2 group. PPC has a protective effect on H 2 O 2 -induced COS-7 cell apoptosis, which is mediated by autophagy activation.

  3. Triptolide induces autophagy and apoptosis through ERK activation in human breast cancer MCF-7 cells.

    Science.gov (United States)

    Gao, Huan; Zhang, Yue; Dong, Lei; Qu, Xiao-Yu; Tao, Li-Na; Zhang, Yue-Ming; Zhai, Jing-Hui; Song, Yan-Qing

    2018-04-01

    To investigate the effects of triptolide (TPI) on proliferation, autophagy and death in human breast cancer MCF-7 cells, and to elucidate the associated molecular mechanisms, intracellular alterations were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays. The results of the MTT assay revealed that TPI significantly reduced the MCF-7 cell survival rate when the concentration was >10 nmol/l. TPI activated a caspase cascade reaction by regulating Bcl-2-associated X protein (Bax), caspase-3 and B-cell lymphoma 2 expression, and promoted programmed cell death via the mitochondrial pathway. The results demonstrated that TPI significantly reduced the cell proliferation rate and viability in a time- and dose-dependent manner, which was confirmed by western blotting and immunofluorescent staining. TPI induced autophagy and influenced p38 mitogen-activated protein kinases, extracellular signal-regulated kinase (Erk)1/2, and mammalian target of rapamycin (mTOR) phosphorylation, which resulted in apoptosis. When cells were treated with a combination of TPI and the Erk1/2 inhibitor U0126, the downregulation of P62 and upregulation of Bax were inhibited, which demonstrated that the inhibition of Erk1/2 reversed the autophagy changes induced by TPI. The results indicated that Erk1/2 activation may be a novel mechanism by which TPI induces autophagy and apoptosis in MCF-7 breast cancer cells. In conclusion, TPI affects the proliferation and apoptosis of MCF-7 cells, potentially via autophagy and p38/Erk/mTOR phosphorylation. The present study offers a novel view of the mechanisms by which TPI regulates cell death.

  4. 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.

  5. 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. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  6. Autophagy as a potential target for sarcoma treatment.

    Science.gov (United States)

    Min, Li; Choy, Edwin; Pollock, Raphael E; Tu, Chongqi; Hornicek, Francis; Duan, Zhenfeng

    2017-08-01

    Autophagy is a constitutively active, evolutionary conserved, catabolic process for maintaining homeostasis in cellular stress responses and cell survival. Although its mechanism has not been fully illustrated, recent work on autophagy in various types of sarcomas has demonstrated that autophagy exerts an important role in sarcoma cell growth and proliferation, in pro-survival response to therapies and stresses, and in therapeutic resistance of sarcoma. Thus, the autophagic process is being seen as a possibly novel therapeutic target of sarcoma. Additionally, some co-regulators of autophagy have also been investigated as promising biomarkers for the diagnosis and prognosis of sarcoma. In this review, we summarize contemporary advances in the role of autophagy in sarcoma and discuss the potential of autophagy as a new target for sarcoma treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. 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

    2014-01-01

    ABSTRACT 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. PMID:24618251

  8. 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. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Molecular mechanisms of autophagy and its role in cancer development

    Directory of Open Access Journals (Sweden)

    Kathleen Salazar-Ramírez

    2016-07-01

    The role of autophagy in the treatment of cancer is described as a “double-edged sword”, which reflects its involvement in tumor suppression, survival and subsequent proliferation of tumor cells. Recent advances are useful for planning appropriate adjustments to inhibit or promote autophagy in order to obtain therapeutic efficacy in cancer patients. The objectives of this review are to clarify the role of autophagy in cancer and to highlight the need for more research in the field.

  10. 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.

  11. Glomerular filtration rate determined in conjunction with routine renal scanning

    International Nuclear Information System (INIS)

    Jackson, J.H.; Blue, P.W.; Ghaed, N.

    1985-01-01

    A method has been developed to estimate glomerular filtration rate using computer evaluation of images obtained during routine renal scanning. The technique requires less than 40 minutes of imaging time, requires only a single blood sample and correlates highly with 24 hour creatinine clearance

  12. 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...

  13. Estimated Glomerular Filtration Rate and Risk of Survival in Acute ...

    African Journals Online (AJOL)

    Objective: To assess the risk of survival in acute stroke using the MDRD equation derived estimated glomerular filtration rate. Design: A prospective observational cross-sectional study. Setting: Medical wards of a tertiary care hospital. Subjects: Eighty three acute stroke patients had GFR calculated within 48 hours of ...

  14. Estimated glomerular filtration rate at initiation of hemodialysis in a ...

    African Journals Online (AJOL)

    Background: Renal replacement therapy is indicated for patients with end-stage renal disease (ESRD). The glomerular filtration rate (GFR) of ESRD patients at initiation of hemodialysis vary depending on several factors including comorbidities, physicians' practice and geographical region amongst others. Aim: We ...

  15. Glomerular filtration rate in steady state children with sickle cell ...

    African Journals Online (AJOL)

    Background: Sickle cell anaemia (SCA) affects mostly people of African origin. It causes kidney problems termed Sickle cell nephropathy (SCN). Increased glomerular filtration rate (GFR) has been documented as one of the functional abnormalities seen in young SCA patients. Objective: To estimate GFR in Nigerian ...

  16. Effect of glycaemic control on glomerular filtration rate in Diabetes ...

    African Journals Online (AJOL)

    Background: Glomerular filtration rate (GFR) is a widely accepted parameter in assessing overall renal function. This study sought to assess the effect of glucose lowering on GFR in diabetic patients admitted for short term therapy at Mulago hospital. Methods: This was a descriptive study where consenting patients were ...

  17. Evaluation of Serum Cystatin C as an Indicator of Glomerular ...

    African Journals Online (AJOL)

    Background: The Glomerular Filtration Rate (GFR) is the best indicator of renal function. Serum cystatin C has been introduced as an endogenous marker of GFR. However, there are conflicting reports regarding its use in pregnancy and pre-eclampsia. We aimed to assess the GFR changes in pre-eclampsia, evaluate the ...

  18. Parietal cells-new perspectives in glomerular disease.

    Science.gov (United States)

    Miesen, Laura; Steenbergen, Eric; Smeets, Bart

    2017-07-01

    In normal glomeruli, parietal epithelial cells (PECs) line the inside of Bowman's capsule and form an inconspicuous sheet of flat epithelial cells in continuity with the proximal tubular epithelial cells (PTECs) at the urinary pole and with the podocytes at the vascular pole. PECs, PTECs and podocytes have a common mesenchymal origin and are the result of divergent differentiation during embryogenesis. Podocytes and PTECs are highly differentiated cells with well-established functions pertaining to the maintenance of the filtration barrier and transport, respectively. For PECs, no specific function other than a structural one has been known until recently. Possible important functions for PECs in the fate of the glomerulus in glomerular disease have now become apparent: (1) PECs may be involved in the replacement of lost podocytes; (2) PECs form the basis of extracapillary proliferative lesions and subsequent sclerosis in glomerular disease. In addition to the acknowledgement that PECs are crucial in glomerular disease, knowledge has been gained regarding the molecular processes driving the phenotypic changes and behavior of PECs. Understanding these molecular processes is important for the development of specific therapeutic approaches aimed at either stimulation of the regenerative function of PECs or inhibition of the pro-sclerotic action of PECs. In this review, we discuss recent advances pertaining to the role of PECs in glomerular regeneration and disease and address the major molecular processes involved.

  19. Structural Alterations of the Glomerular Wall And Vessels in Early ...

    African Journals Online (AJOL)

    Structural Alterations of the Glomerular Wall And Vessels in Early Stages of Diabetes Mellitus: Light and Transmission Electron Microscopic Study. ... 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, ...

  20. Important clinical and laboratory correlates of glomerular filtration ...

    African Journals Online (AJOL)

    2015-02-03

    Feb 3, 2015 ... associated with laboratory indicators of hemolysis in this group of patients.[6] Progression of sickle nephropathy can. Important clinical and laboratory correlates of glomerular filtration rate in sickle cell anemia. AJ Madu, A Ubesie1, S Ocheni, J Chinawa1, KA Madu2, OG Ibegbulam, C Nlemadim3, A Eze3.

  1. 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.

  2. 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.

  3. 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.

  4. Inhibition of Cellular Autophagy Deranges Dengue Virion Maturation

    Science.gov (United States)

    Mateo, Roberto; Nagamine, Claude M.; Spagnolo, Jeannie; Méndez, Ernesto; Rahe, Michael; Gale, Michael; Yuan, Junying

    2013-01-01

    Autophagy is an important component of the innate immune response, directly destroying many intracellular pathogens. However, some pathogens, including several RNA viruses, subvert the autophagy pathway, or components of the pathway, to facilitate their replication. In the present study, the effect of inhibiting autophagy on the growth of dengue virus was tested using a novel inhibitor, spautin-1 (specific and potent autophagy inhibitor 1). Inhibition of autophagy by spautin-1 generated heat-sensitive, noninfectious dengue virus particles, revealing a large effect of components of the autophagy pathway on viral maturation. A smaller effect on viral RNA accumulation was also observed. Conversely, stimulation of autophagy resulted in increased viral titers and pathogenicity in the mouse. We conclude that the presence of functional autophagy components facilitates viral RNA replication and, more importantly, is required for infectious dengue virus production. Pharmacological inhibition of host processes is an attractive antiviral strategy to avoid selection of treatment-resistant variants, and inhibitors of autophagy may prove to be valuable therapeutics against dengue virus infection and pathogenesis. PMID:23175363

  5. AMPK regulates autophagy by phosphorylating BECN1 at threonine 388

    Science.gov (United States)

    Zhang, Deyi; Wang, Wei; Sun, Xiujie; Xu, Daqian; Wang, Chenyao; Zhang, Qian; Wang, Huafei; Luo, Wenwen; Chen, Yan; Chen, Huaiyong; Liu, Zhixue

    2016-01-01

    ABSTRACT Macroautophagy/autophagy is a conserved catabolic process that recycles cytoplasmic material during low energy conditions. BECN1/Beclin1 (Beclin 1, autophagy related) is an essential protein for function of the class 3 phosphatidylinositol 3-kinase (PtdIns3K) complexes that play a key role in autophagy nucleation and elongation. Here, we show that AMP-activated protein kinase (AMPK) regulates autophagy by phosphorylating BECN1 at Thr388. Phosphorylation of BECN1 is required for autophagy upon glucose withdrawal. BECN1T388A, a phosphorylation defective mutant, suppresses autophagy through decreasing the interaction between PIK3C3 (phosphatidylinositol 3-kinase catalytic subunit type 3) and ATG14 (autophagy-related 14). The BECN1T388A mutant has a higher affinity for BCL2 than its wild-type counterpart; the mutant is more prone to dimer formation. Conversely, a BECN1 phosphorylation mimic mutant, T388D, has stronger binding to PIK3C3 and ATG14, and promotes higher autophagy activity than the wild-type control. These findings uncover a novel mechanism of autophagy regulation. PMID:27304906

  6. Regulation of autophagy by cytosolic acetyl-coenzyme A

    DEFF Research Database (Denmark)

    Mariño, Guillermo; Pietrocola, Federico; Eisenberg, Tobias

    2014-01-01

    levels inhibited maladaptive autophagy in a model of cardiac pressure overload. Depletion of AcCoA reduced the activity of the acetyltransferase EP300, and EP300 was required for the suppression of autophagy by high AcCoA levels. Altogether, our results indicate that cytosolic AcCoA functions...... proteins, as well as the induction of autophagy, a homeostatic process of self-digestion. Multiple distinct manipulations designed to increase or reduce cytosolic AcCoA led to the suppression or induction of autophagy, respectively, both in cultured human cells and in mice. Moreover, maintenance of high AcCoA...

  7. 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.

  8. Quiltophagy--autophagy as folk art.

    Science.gov (United States)

    Crumrine, Barbara M; Klionsky, Daniel J

    2015-01-01

    Over the years macroautophagy (hereafter autophagy) has been depicted artistically through painting, music, dance, videos, and poetry. A unifying idea behind these different aesthetic approaches is that people learn in different ways. Thus, some learners may be engaged by a detailed, but static, painting, whereas others may find insight through the dynamic visualization provided by a dance. While each of these formats has advantages, they also have a common weakness--whether delivered through watercolor on a canvas, words on a paper, or movement captured in a video, they are all 2-dimensional. Yet, some people are tactile learners. In this paper, a quilter describes a project she created with the goal of demonstrating autophagy using a 3-dimensional approach, in which different fiber textures could be used to elaborate certain parts of the process.

  9. 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 mi......RNAs to regulation of the autophagy pathway. This regulation occurs both through specific core pathway components as well as through less well-defined mechanisms. Although this field is still in its infancy, we are beginning to understand the potential implications of these initial findings, both from a pathological...

  10. Persistent decline in estimated but not measured glomerular filtration rate on tenofovir may reflect tubular rather than glomerular toxicity

    NARCIS (Netherlands)

    Vrouenraets, Saskia M. E.; Fux, Christoph A.; Wit, Ferdinand W. N. M.; Garcia, Evian Fernandez; Furrer, Hansjakob; Brinkman, Kees; Hoek, Frans J.; Abeling, Nico G. G. M.; Krediet, Ray T.; Reiss, Peter

    2011-01-01

    Tenofovir disoproxil fumarate (TDF) has been associated with proximal renal tubulopathy and reduction in estimated glomerular filtration rate (eGFR), without accounting for the tubular secretion of creatinine. A substudy was performed among 19 participants of a randomized 48-week trial, comparing

  11. 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

  12. Activation of RARα induces autophagy in SKBR3 breast cancer cells and depletion of key autophagy genes enhances ATRA toxicity.

    Science.gov (United States)

    Brigger, D; Schläfli, A M; Garattini, E; Tschan, M P

    2015-08-27

    All-trans retinoic acid (ATRA), a pan-retinoic acid receptor (RAR) agonist, is, along with other retinoids, a promising therapeutic agent for the treatment of a variety of solid tumors. On the one hand, preclinical studies have shown promising anticancer effects of ATRA in breast cancer; on the other hand, resistances occurred. Autophagy is a cellular recycling process that allows the degradation of bulk cellular contents. Tumor cells may take advantage of autophagy to cope with stress caused by anticancer drugs. We therefore wondered if autophagy is activated by ATRA in mammary tumor cells and if modulation of autophagy might be a potential novel treatment strategy. Indeed, ATRA induces autophagic flux in ATRA-sensitive but not in ATRA-resistant human breast cancer cells. Moreover, using different RAR agonists as well as RARα-knockdown breast cancer cells, we demonstrate that autophagy is dependent on RARα activation. Interestingly, inhibition of autophagy in breast cancer cells by either genetic or pharmacological approaches resulted in significantly increased apoptosis under ATRA treatment and attenuated epithelial differentiation. In summary, our findings demonstrate that ATRA-induced autophagy is mediated by RARα in breast cancer cells. Furthermore, inhibition of autophagy results in enhanced apoptosis. This points to a potential novel treatment strategy for a selected group of breast cancer patients where ATRA and autophagy inhibitors are applied simultaneously.

  13. Autophagy: A brief overview in perspective of dermatology

    Directory of Open Access Journals (Sweden)

    Rahul Nagar

    2017-01-01

    Full Text Available Autophagy, literally meaning “self-eating,” is an intracellular catabolic process of delivering cytosol and/or its specific content to the lysosomes for degradation.The resulting macromolecular constituents are recycled and utilized again by the cells. Basal level autophagy plays an important role in cellular homeostasis through the elimination of the old or damaged organelles, as well as aggregated intracellular proteins. Autophagy refers to sequestration of intact organelles along with a portion of cytosol, into a double-or multi-membrane structure known as phagophore, which elongates, and after closure, forms a vesicular structure known as the autophagosome. Subsequently, the mature autophagosome fuses with a lysosome, thereby forming a single membrane structure, an autolysosome. Autophagy plays a critical role in inflammation, autoimmunity and cellular differentiation. Skin serves as the first line of defense against a variety of environmental insults and autophagy is thought to be a form of an endogenous defense mechanism against such environmental derangements. Autophagy has been linked with keratinocyte differentiation and melanocyte survival, as well as with the pathogenesis of diverse skin disorders including systemic lupus erythematosus, systemic sclerosis, psoriasis, vitiligo, infectious skin diseases and cancer. Autophagy has been one of the most studied phenomena in cell biology and pathophysiology, and given its broad clinical implications, has become a major target for drug discovery. The last decade has seen a substantial upsurge in autophagy-related research and publications; still, the dermatology literature appears to be less initiated. Autophagy will probably change our understanding of dermatological disorders/medicines. Hence, a basic knowledge of autophagy is a prerequisite to understand the developments in the field of autophagy-related research.

  14. Interplay between Autophagy, Exosomes and HIV-1 Associated Neurological Disorders: New Insights for Diagnosis and Therapeutic Applications

    Directory of Open Access Journals (Sweden)

    Chet Raj Ojha

    2017-07-01

    Full Text Available The autophagy–lysosomal pathway mediates a degradative process critical in the maintenance of cellular homeostasis as well as the preservation of proper organelle function by selective removal of damaged proteins and organelles. In some situations, cells remove unwanted or damaged proteins and RNAs through the release to the extracellular environment of exosomes. Since exosomes can be transferred from one cell to another, secretion of unwanted material to the extracellular environment in exosomes may have an impact, which can be beneficial or detrimental, in neighboring cells. Exosome secretion is under the influence of the autophagic system, and stimulation of autophagy can inhibit exosomal release and vice versa. Neurons are particularly vulnerable to degeneration, especially as the brain ages, and studies indicate that imbalances in genes regulating autophagy are a common feature of many neurodegenerative diseases. Cognitive and motor disease associated with severe dementia and neuronal damage is well-documented in the brains of HIV-infected individuals. Neurodegeneration seen in the brain in HIV-1 infection is associated with dysregulation of neuronal autophagy. In this paradigm, we herein provide an overview on the role of autophagy in HIV-associated neurodegenerative disease, focusing particularly on the effect of autophagy modulation on exosomal release of HIV particles and how this interplay impacts HIV infection in the brain. Specific autophagy–regulating agents are being considered for therapeutic treatment and prevention of a broad range of human diseases. Various therapeutic strategies for modulating specific stages of autophagy and the current state of drug development for this purpose are also evaluated.

  15. Captoril suppresses glomerular filtration rate but not blood flow in the affected kidney in renovascular hypertension

    International Nuclear Information System (INIS)

    Fommei, E.; Ghione, S.; Palla, L.; Giaconi, S.; Morraccini, P.; Palombo, C.; Rosa, C.; Gazzetti, P.; Donato, L.

    1985-01-01

    The acute effects of Captopril on glomerular filtration rate and blood flow of the kidney affected by unilateral renal artery stenosis in a patient with renovascular hypertension are reported. The contribution of the stenotic kidney to total glomerular filtration rate and blood flow was assessed by scintigraphic methods, using respectively the glomerular tracer 99m Tc-DTPA and 99m Tc-Albumin microspheres. Captopril induced a marked reduction of glomerular filtration without affecting blood flow. This finding indicates a profound dysruption of Angiotensin II - dependent autoregulation of the glomerular filtration induced by converting enzyme inhibition in renal artery stenosis

  16. 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

  17. Autophagy Inhibition Dysregulates TBK1 Signaling and Promotes Pancreatic Inflammation.

    Science.gov (United States)

    Yang, Shenghong; Imamura, Yu; Jenkins, Russell W; Cañadas, Israel; Kitajima, Shunsuke; Aref, Amir; Brannon, Arthur; Oki, Eiji; Castoreno, Adam; Zhu, Zehua; Thai, Tran; Reibel, Jacob; Qian, Zhirong; Ogino, Shuji; Wong, Kwok K; Baba, Hideo; Kimmelman, Alec C; Pasca Di Magliano, Marina; Barbie, David A

    2016-06-01

    Autophagy promotes tumor progression downstream of oncogenic KRAS, yet also restrains inflammation and dysplasia through mechanisms that remain incompletely characterized. Understanding the basis of this paradox has important implications for the optimal targeting of autophagy in cancer. Using a mouse model of cerulein-induced pancreatitis, we found that loss of autophagy by deletion of Atg5 enhanced activation of the IκB kinase (IKK)-related kinase TBK1 in vivo, associated with increased neutrophil and T-cell infiltration and PD-L1 upregulation. Consistent with this observation, pharmacologic or genetic inhibition of autophagy in pancreatic ductal adenocarcinoma cells, including suppression of the autophagy receptors NDP52 or p62, prolonged TBK1 activation and increased expression of CCL5, IL6, and several other T-cell and neutrophil chemotactic cytokines in vitro Defective autophagy also promoted PD-L1 upregulation, which is particularly pronounced downstream of IFNγ signaling and involves JAK pathway activation. Treatment with the TBK1/IKKε/JAK inhibitor CYT387 (also known as momelotinib) not only inhibits autophagy, but also suppresses this feedback inflammation and reduces PD-L1 expression, limiting KRAS-driven pancreatic dysplasia. These findings could contribute to the dual role of autophagy in oncogenesis and have important consequences for its therapeutic targeting. Cancer Immunol Res; 4(6); 520-30. ©2016 AACR. ©2016 American Association for Cancer Research.

  18. Signalling and autophagy regulation in health, aging and disease

    NARCIS (Netherlands)

    Meijer, Alfred J.; Codogno, Patrice

    2006-01-01

    It has become clear in recent years that autophagy not only serves to produce amino acids for ongoing protein synthesis and to produce substrates for energy production when cells become starved but autophagy is also able to eliminate defective cell structures and for this reason the process may be

  19. Autophagy and its implication in human oral diseases.

    Science.gov (United States)

    Tan, Ya-Qin; Zhang, Jing; Zhou, Gang

    2017-02-01

    Macroautophagy/autophagy is a conserved lysosomal degradation process essential for cell physiology and human health. By regulating apoptosis, inflammation, pathogen clearance, immune response and other cellular processes, autophagy acts as a modulator of pathogenesis and is a potential therapeutic target in diverse diseases. With regard to oral disease, autophagy can be problematic either when it is activated or impaired, because this process is involved in diverse functions, depending on the specific disease and its level of progression. In particular, activated autophagy functions as a cytoprotective mechanism under environmental stress conditions, which regulates tumor growth and mediates resistance to anticancer treatment in established tumors. During infections and inflammation, activated autophagy selectively delivers microbial antigens to the immune systems, and is therefore connected to the elimination of intracellular pathogens. Impaired autophagy contributes to oxidative stress, genomic instability, chronic tissue damage, inflammation and tumorigenesis, and is involved in aberrant bacterial clearance and immune priming. Hence, substantial progress in the study of autophagy provides new insights into the pathogenesis of oral diseases. This review outlines the mechanisms of autophagy, and highlights the emerging roles of this process in oral cancer, periapical lesions, periodontal diseases, and oral candidiasis.

  20. Role of Autophagy in Cisplatin Resistance in Ovarian Cancer Cells*

    Science.gov (United States)

    Wang, Juan; Wu, Gen Sheng

    2014-01-01

    Cisplatin-based treatment is the first line chemotherapy for several cancers including ovarian cancer. The development of cisplatin resistance results in treatment failure, but the underlying mechanisms are not fully understood. Here we show that the induction of autophagy plays an important role in cisplatin resistance in ovarian cancer cells. Specifically, we show that cisplatin resistance is correlated with autophagy induction in a panel of ovarian cancer cells but not in immortalized human ovarian surface epithelial cells. Mechanistically, cisplatin treatment activates ERK and subsequently promotes autophagy. The inhibition of ERK activation with MEK inhibitors or knockdown of ERK expression with siRNA decreases cisplatin-induced autophagy and subsequently sensitizes ovarian cancer cells to cisplatin-induced apoptosis. In ovarian cancer cells that have developed acquired cisplatin resistance, both ERK activation and autophagy induction are increased. Importantly, knockdown of ERK or inhibition of autophagy promotes cisplatin-induced apoptosis in acquired cisplatin-resistant cells. Collectively, our data indicate that ERK-mediated autophagy can lead to cisplatin resistance and suggest that cisplatin resistance can be overcome by inhibition of autophagy in ovarian cancer cells. PMID:24794870

  1. The Nobel Prize for understanding autophagy, a cellular mechanism ...

    Indian Academy of Sciences (India)

    This processof autophagy (self-eating) maintains cellular homeostasis and helps the cell and the organism to surviveduring periods of stress, such as starvation, by recycling the cellular components to generate amino acidsand nutrients needed for producing energy. Autophagy and ubiquitin-proteasome system are the two ...

  2. Autophagy-dependent secretion: contribution to tumor progression

    Directory of Open Access Journals (Sweden)

    Tom Keulers

    2016-11-01

    Full Text Available Autophagy is best known as a lysosomal degradation and recycling pathway to maintain cellular homeostasis. During autophagy, cytoplasmic content is recognized and packed in autophagic vacuoles, or autophagosomes, and targeted for degradation. However, during the last years, it has become evident that the role of autophagy is not restricted to degradation alone but also mediates unconventional forms of secretion. Furthermore, cells with defects in autophagy apparently are able to reroute their cargo, like mitochondria, to the extracellular environment; effects that contribute to an array of pathologies. In this review we discuss the current knowledge of the physiological roles of autophagy-dependent secretion, i.e. the effect on inflammation and insulin/ hormone secretion. Finally, we focus on the effects of autophagy-dependent secretion on the tumour microenvironment and tumour progression. The autophagy mediated secreted factors may stimulate cellular proliferation via auto- and paracrine signaling. The autophagy mediated release of immune modulating proteins change the immunosuppresive tumor microenvironment and may promote an invasive phenotype. These effects may be either direct or indirect through facilitating formation of the mobilized vesicle, aid in anterograde trafficking or alterations in homeostasis and/or autonomous cell signaling.

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

    NARCIS (Netherlands)

    Codogno, Patrice; Meijer, Alfred J.

    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

  4. Autophagy Is Required for Neutrophil-Mediated Inflammation

    Directory of Open Access Journals (Sweden)

    Abhisek Bhattacharya

    2015-09-01

    Full Text Available Autophagy, an intracellular degradation and energy recycling mechanism, is emerging as an important regulator of immune responses. However, the role of autophagy in regulating neutrophil functions is not known. We investigated neutrophil biology using myeloid-specific autophagy-deficient mice and found that autophagy deficiency reduced neutrophil degranulation in vitro and in vivo. Mice with autophagy deficiency showed reduced severity of several neutrophil-mediated inflammatory and autoimmune disease models, including PMA-induced ear inflammation, LPS-induced breakdown of blood-brain barrier, and experimental autoimmune encephalomyelitis. NADPH oxidase-mediated reactive oxygen species generation was also reduced in autophagy-deficient neutrophils, and inhibition of NADPH oxidase reduced neutrophil degranulation, suggesting NADPH oxidase to be a player at the intersection of autophagy and degranulation. Overall, this study establishes autophagy as an important regulator of neutrophil functions and neutrophil-mediated inflammation in vivo.

  5. Autophagy Primes Neutrophils for Neutrophil Extracellular Trap Formation during Sepsis.

    Science.gov (United States)

    Park, So Young; Shrestha, Sanjeeb; Youn, Young-Jin; Kim, Jun-Kyu; Kim, Shin-Yeong; Kim, Hyun Jung; Park, So-Hee; Ahn, Won-Gyun; Kim, Shin; Lee, Myung Goo; Jung, Ki-Suck; Park, Yong Bum; Mo, Eun-Kyung; Ko, Yousang; Lee, Suh-Young; Koh, Younsuck; Park, Myung Jae; Song, Dong-Keun; Hong, Chang-Won

    2017-09-01

    Neutrophils are key effectors in the host's immune response to sepsis. Excessive stimulation or dysregulated neutrophil functions are believed to be responsible for sepsis pathogenesis. However, the mechanisms regulating functional plasticity of neutrophils during sepsis have not been fully determined. We investigated the role of autophagy in neutrophil functions during sepsis in patients with community-acquired pneumonia. Neutrophils were isolated from patients with sepsis and stimulated with phorbol 12-myristate 13-acetate (PMA). The levels of reactive oxygen species generation, neutrophil extracellular trap (NET) formation, and granule release, and the autophagic status were evaluated. The effect of neutrophil autophagy augmentation was further evaluated in a mouse model of sepsis. Neutrophils isolated from patients who survived sepsis showed an increase in autophagy induction, and were primed for NET formation in response to subsequent PMA stimulation. In contrast, neutrophils isolated from patients who did not survive sepsis showed dysregulated autophagy and a decreased response to PMA stimulation. The induction of autophagy primed healthy neutrophils for NET formation and vice versa. In a mouse model of sepsis, the augmentation of autophagy improved survival via a NET-dependent mechanism. These results indicate that neutrophil autophagy primes neutrophils for increased NET formation, which is important for proper neutrophil effector functions during sepsis. Our study provides important insights into the role of autophagy in neutrophils during sepsis.

  6. Host-pathogen interactions and subversion of autophagy.

    Science.gov (United States)

    McEwan, David G

    2017-12-12

    Macroautophagy ('autophagy'), is the process by which cells can form a double-membraned vesicle that encapsulates material to be degraded by the lysosome. This can include complex structures such as damaged mitochondria, peroxisomes, protein aggregates and large swathes of cytoplasm that can not be processed efficiently by other means of degradation. Recycling of amino acids and lipids through autophagy allows the cell to form intracellular pools that aid survival during periods of stress, including growth factor deprivation, amino acid starvation or a depleted oxygen supply. One of the major functions of autophagy that has emerged over the last decade is its importance as a safeguard against infection. The ability of autophagy to selectively target intracellular pathogens for destruction is now regarded as a key aspect of the innate immune response. However, pathogens have evolved mechanisms to either evade or reconfigure the autophagy pathway for their own survival. Understanding how pathogens interact with and manipulate the host autophagy pathway will hopefully provide a basis for combating infection and increase our understanding of the role and regulation of autophagy. Herein, we will discuss how the host cell can identify and target invading pathogens and how pathogens have adapted in order to evade destruction by the host cell. In particular, we will focus on interactions between the mammalian autophagy gene 8 (ATG8) proteins and the host and pathogen effector proteins. © 2017 The Author(s).

  7. 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.

  8. 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.

  9. Inhibition of autophagy as a treatment strategy for p53 wild-type acute myeloid leukemia

    NARCIS (Netherlands)

    Folkerts, Hendrik; Hilgendorf, Susan; Wierenga, Albertus T J; Jaques, Jennifer; Mulder, André B; Coffer, Paul J; Schuringa, Jan Jacob; Vellenga, Edo

    2017-01-01

    Here we have explored whether inhibition of autophagy can be used as a treatment strategy for acute myeloid leukemia (AML). Steady-state autophagy was measured in leukemic cell lines and primary human CD34(+) AML cells with a large variability in basal autophagy between AMLs observed. The autophagy

  10. The Effect of Alium Satium Extract on the Glomerular Diameter of STZ -induced Sprague dawley Rats

    Directory of Open Access Journals (Sweden)

    Susilorini Susilorini

    2013-06-01

    Full Text Available Hyperglycemia exert toxic effect in kidney.The aim of this study was to investigate the short term effect of ethanolic extract of garlic in preventing nephropathy following streptozotocin (STZ induced rats. Twenty male Sprague dawley rats were randomly divided into 4 group, all group induced induced by single dose intraperitoneal injection of 40 mg kg-1 of streptozotocin (STZ. Treatment with 3 doses ethanolic extract of garlic (0,1; 0,25; 0,5 mg kg-1 day-1 was followed for 14 days, then the left kidneys were excised and histhopathological studies were carried out using scanner 3D Hitech and Panoramic view software. Statistical analysis have been done using non parametric analysis Kruskall Wallis. The study revealed that glomerular diameter of the treatment rats was significantly different from the control group (p=0,0001. Increasing doses didn’t make difference. The ethanolic extract of garlic (Allium sativum influences the diameter glomeruli but increasing doses has no effect on the glomerular diameter.

  11. Autophagy in Drosophila: From Historical Studies to Current Knowledge

    Science.gov (United States)

    Mulakkal, Nitha C.; Nagy, Peter; Takats, Szabolcs; Tusco, Radu; Juhász, Gábor; Nezis, Ioannis P.

    2014-01-01

    The discovery of evolutionarily conserved Atg genes required for autophagy in yeast truly revolutionized this research field and made it possible to carry out functional studies on model organisms. Insects including Drosophila are classical and still popular models to study autophagy, starting from the 1960s. This review aims to summarize past achievements and our current knowledge about the role and regulation of autophagy in Drosophila, with an outlook to yeast and mammals. The basic mechanisms of autophagy in fruit fly cells appear to be quite similar to other eukaryotes, and the role that this lysosomal self-degradation process plays in Drosophila models of various diseases already made it possible to recognize certain aspects of human pathologies. Future studies in this complete animal hold great promise for the better understanding of such processes and may also help finding new research avenues for the treatment of disorders with misregulated autophagy. PMID:24949430

  12. Monitoring Autophagy in the Model Green Microalga Chlamydomonas reinhardtii

    Directory of Open Access Journals (Sweden)

    María Esther Pérez-Pérez

    2017-10-01

    Full Text Available Autophagy is an intracellular catabolic system that delivers cytoplasmic constituents and organelles in the vacuole. This degradative process is mediated by a group of proteins coded by autophagy-related (ATG genes that are widely conserved from yeasts to plants and mammals. Homologs of ATG genes have been also identified in algal genomes including the unicellular model green alga Chlamydomonas reinhardtii. The development of specific tools to monitor autophagy in Chlamydomonas has expanded our current knowledge about the regulation and function of this process in algae. Recent findings indicated that autophagy is regulated by redox signals and the TOR network in Chlamydomonas and revealed that this process may play in important role in the control of lipid metabolism and ribosomal protein turnover in this alga. Here, we will describe the different techniques and approaches that have been reported to study autophagy and autophagic flux in Chlamydomonas.

  13. 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.

  14. Bim Inhibits Autophagy by Recruiting Beclin 1 to Microtubules

    Science.gov (United States)

    Luo, Shouqing; Garcia-Arencibia, Moises; Zhao, Rui; Puri, Claudia; Toh, Pearl P.C.; Sadiq, Oana; Rubinsztein, David C.

    2012-01-01

    Summary Bim is a proapoptotic BH3-only Bcl-2 family member. In response to death stimuli, Bim dissociates from the dynein light chain 1 (DYNLL1/LC8), where it is inactive, and can then initiate Bax/Bak-mediated mitochondria-dependent apoptosis. We found that Bim depletion increases autophagosome synthesis in cells and in vivo, and this effect is inhibited by overexpression of cell death-deficient Bim. Bim inhibits autophagy by interacting with Beclin 1, an autophagy regulator, and this interaction is facilitated by LC8. Bim bridges the Beclin 1-LC8 interaction and thereby inhibits autophagy by mislocalizing Beclin 1 to the dynein motor complex. Starvation, an autophagic stimulus, induces Bim phosphorylation, which abrogates LC8 binding to Bim, leading to dissociation of Bim and Beclin 1. Our data suggest that Bim switches locations between apoptosis-inactive/autophagy-inhibitory and apoptosis-active/autophagy-permissive sites. PMID:22742832

  15. Subversion of the cellular autophagy pathway by viruses.

    Science.gov (United States)

    Kirkegaard, Karla

    2009-01-01

    Autophagy is a cellular process that creates double-membraned vesicles, engulfs and degrades cytoplasmic material, and generates and recycles nutrients. A recognized participant in the innate immune response to microbial infection, a functional autophagic response can help to control the replication of many viruses. However, for several viruses, there is functional and mechanistic evidence that components of the autophagy pathway act as host factors in viral replicative cycles, viral dissemination, or both. Investigating the mechanisms by which viruses subvert or imitate autophagy, as well as the mechanisms by which they inhibit autophagy, will reveal cell biological tools and processes that will be useful for understanding the many functional ramifications of the double-membraned vesicle formation and cytosolic entrapment unique to the autophagy pathway.

  16. A simple method for the estimation of glomerular filtration rate

    International Nuclear Information System (INIS)

    Groth, T.; Tengstroem, B.

    1977-01-01

    A simple method is presented for indirect estimation of the glomerular filtration rate from two venous blood samples, drawn after a single injection of a small dose of [ 125 I]sodium iothalamate (10 μCi). The method does not require exact dosage, as the first sample, taken after a few minutes (t=5 min) after injection, is used to normilize the value of the second sample, which should be taken in between 2-4 h after injection. The glomerular filtration rate, as measured by standard inulin clearance, may then be predicted from the logarithm of the normalized value and linear regression formulas with a standard error of estimate of the order of 1-2 ml/min/1.73 m 2 . The slope-intercept method for direct estimation of glomerular filtration rate is also evaluated and found to significantly underestimate standard insulin clearance. The normalized 'single-point' method is concluded to be superior to the slope-intercept method and more sophisticated methods using curve fitting technique, with regard to predictive force and clinical applicability. (Auth.)

  17. Intraglomerular microcirculation: measurements of single glomerular loop flow in rats.

    Science.gov (United States)

    Steinhausen, M; Zimmerhackl, B; Thederan, H; Dussel, R; Parekh, N; Esslinger, H U; von Hagens, G; Komitowski, D; Dallenbach, F D

    1981-08-01

    With the use of a new fluorescent microscopic technique, we were able to measure the mean intracapillary velocities and pressures of single capillary loops of renal glomeruli of living rats. The technique involved photographing and recording the flow of fluorescent latex particles through the glomerular loops with a television monitor. In 25 rats the single glomerular loop flow velocity was 781 +/- (SD) 271 micrometers . sec-1. The mean diameter of the capillary loops measured 8.4 +/- 1.4 micrometers; their lengths were 72.3 +/- 37.5 micrometers. From the decrease in velocity of flow along the capillary loop, we were able to evaluate the filtration equivalent for the capillary surface. It was possible to measure intracapillary pressures of single glomerular loops continuously under microscopic control. High intracapillary pressures correlated with high intracapillary velocities. From the data we obtained, we were unable to calculate a filtration equilibrium at the ends of the observed capillary loops. For further correlations, we injected the glomeruli we had studied in the living state and examined them with the scanning electron microscope.

  18. Loss of endogenous thymosin β4 accelerates glomerular disease.

    Science.gov (United States)

    Vasilopoulou, Elisavet; Kolatsi-Joannou, Maria; Lindenmeyer, Maja T; White, Kathryn E; Robson, Michael G; Cohen, Clemens D; Sebire, Neil J; Riley, Paul R; Winyard, Paul J; Long, David A

    2016-11-01

    Glomerular disease is characterized by morphologic changes in podocyte cells accompanied by inflammation and fibrosis. Thymosin β 4 regulates cell morphology, inflammation, and fibrosis in several organs and administration of exogenous thymosin β 4 improves animal models of unilateral ureteral obstruction and diabetic nephropathy. However, the role of endogenous thymosin β 4 in the kidney is unknown. We demonstrate that thymosin β 4 is expressed prominently in podocytes of developing and adult mouse glomeruli. Global loss of thymosin β 4 did not affect healthy glomeruli, but accelerated the severity of immune-mediated nephrotoxic nephritis with worse renal function, periglomerular inflammation, and fibrosis. Lack of thymosin β 4 in nephrotoxic nephritis led to the redistribution of podocytes from the glomerular tuft toward the Bowman capsule suggesting a role for thymosin β 4 in the migration of these cells. Thymosin β 4 knockdown in cultured podocytes also increased migration in a wound-healing assay, accompanied by F-actin rearrangement and increased RhoA activity. We propose that endogenous thymosin β 4 is a modifier of glomerular injury, likely having a protective role acting as a brake to slow disease progression. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  19. 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. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. Pravastatin Protects Against Avascular Necrosis of Femoral Head via Autophagy.

    Science.gov (United States)

    Liao, Yun; Zhang, Ping; Yuan, Bo; Li, Ling; Bao, Shisan

    2018-01-01

    Autophagy serves as a stress response and may contribute to the pathogenesis of avascular necrosis of the femoral head induced by steroids. Statins promote angiogenesis and ameliorate endothelial functions through apoptosis inhibition and necrosis of endothelial progenitor cells, however the process used by statins to modulate autophagy in avascular necrosis of the femoral head remains unclear. This manuscript determines whether pravastatin protects against dexamethasone-induced avascular necrosis of the femoral head by activating endothelial progenitor cell autophagy. Pravastatin was observed to enhance the autophagy activity in endothelial progenitor cells, specifically by upregulating LC3-II/Beclin-1 (autophagy related proteins), and autophagosome formation in vivo and in vitro . An autophagy inhibitor, 3-MA, reduced pravastatin protection in endothelial progenitor cells exposed to dexamethasone by attenuating pravastatin-induced autophagy. Adenosine monophosphate-activated protein kinase (AMPK) is a key autophagy regulator by sensing cellular energy changes, and indirectly suppressing activation of the mammalian target of rapamycin (mTOR). We found that phosphorylation of AMPK was upregulated however phosphorylation of mTOR was downregulated in pravastatin-treated endothelial progenitor cells, which was attenuated by AMPK inhibitor compound C. Furthermore, liver kinase B1 (a phosphorylase of AMPK) knockdown eliminated pravastatin regulated autophagy protein LC3-II in endothelial progenitor cells in vitro . We therefore demonstrated pravastatin rescued endothelial progenitor cells from dexamethasone-induced autophagy dysfunction through the AMPK-mTOR signaling pathway in a liver kinase B1-dependent manner. Our results provide useful information for the development of novel therapeutics for management of glucocorticoids-induced avascular necrosis of the femoral head.

  1. Autophagy and leucine promote chronological longevity and respiration proficiency during calorie restriction in yeast

    OpenAIRE

    Aris, John P.; Alvers, Ashley L.; Ferraiuolo, Roy A.; Fishwick, Laura K.; Hanvivatpong, Amanda; Hu, Doreen; Kirlew, Christine; Leonard, Michael T.; Losin, Kyle J.; Marraffini, Michelle; Seo, Arnold Y.; Swanberg, Veronica; Westcott, Jennifer L.; Wood, Michael S.; Leeuwenburgh, Christiaan

    2013-01-01

    We have previously shown that autophagy is required for chronological longevity in the budding yeast Saccharomyces cerevisiae. Here we examine the requirements for autophagy during extension of chronological life span (CLS) by calorie restriction (CR). We find that autophagy is upregulated by two CR interventions that extend CLS: water wash CR and low glucose CR. Autophagy is required for full extension of CLS during water wash CR under all growth conditions tested. In contrast, autophagy was...

  2. [Advances in the Research of the Regulation of Chinese Traditional Medicine Monomer and Its Derivatives on Autophagy in Non-small Cell Lung Cancer].

    Science.gov (United States)

    Xiang, Meiyi; Li, Ruilei; Zhang, Zhiwei; Song, Xin

    2017-03-20

    The high morbidity and mortality of non-small cell lung cancer (NSCLC) did influence the quality of life of tumor patients world-wide. There is an urgent need to develop new therapies that have high anti-tumor activity and low toxicity side effects. It is widely accepted that autophagy can play diverse roles in carcinogenesis, such as induces pro-death of lung cancer cells or helps the escape from cell death, making it become a proper anticancer target. It's believed that various monomers of Chinese traditional medicine closely correlates to anti-NSCLC activities, and that even could affect the acquired multiple drug resistance (MDR). Furthermore, autophagy might be the underling mechanisms which could play a role as the candidate targets of natural active compounds. Recent studies of terpenoids, alkaloid, dietary polyphenols, saponins and other active ingredients that extracted from a large variety of herbs suggest that different monomer compounds could either regulate the activity of pro-death autophagy or influence the level of protective autophagy of NSCLC cells, thus changing their drug sensitivity and cell viability. This paper aims to give a systemic description of the latest advances about natural compounds and their derivatives that involved in tumorigenesis of NSCLC via inducing the autophagy.

  3. Change in glomerular volume and its clinicopathological impact after kidney transplantation.

    Science.gov (United States)

    Kobayashi, Akimitsu; Yamamoto, Izumi; Katsumata, Haruki; Yamakawa, Takafumi; Mafune, Aki; Nakada, Yasuyuki; Koike, Kentaro; Mitome, Jun; Miki, Jun; Yamada, Hiroki; Tanno, Yudo; Ohkido, Ichiro; Tsuboi, Nobuo; Yokoyama, Keitaro; Yamamoto, Hiroyasu; Yokoo, Takashi

    2015-07-01

    Both immunological and non-immunological etiologies affect graft function after kidney transplantation, including acute rejection, calcineurin inhibitor toxicity, and a recurrence of glomerulonephritis. Glomerular enlargement or glomerular sclerosis due to glomerular hyperfiltration related to increased renal blood flow is another cause. Although the glomerular volume in baseline biopsies predicts late allograft function, the relationship between allograft function and the annual changes in glomerular volume after kidney transplantation are unclear. We investigated changes in glomerular volume after kidney transplantation and their clinicopathological relationship. We enrolled 23 patients with stable kidney function without an episode of rejection or any complication resulting in a functional decrease in the graft. We measured glomerular volume (GV) using the Weibel-Gomez method and glomerular density (GD) using 0,1 h biopsy samples as baseline controls and 1 yr biopsy samples and investigated the association between the changes in them and clinical parameters, including graft function, proteinuria, and renal hemodynamic markers, including effective renal plasma flow (ERPF) and filtration fraction (FF). The ERPF was calculated from a 99mTc-mercaptoacetyltriglycine (MAG3) renogram. The GV and ERPF increased significantly 1 yr after kidney transplantation. In contrast, proteinuria decreased significantly and Δproteinuria (1 yr - 1 month after transplantation) was correlated with ΔGV (P Glomerular enlargement 1 yr after transplantation may be related to improved proteinuria. It is possible that glomerular enlargement serves as a renal adaptation after kidney transplantation. © 2015 Asian Pacific Society of Nephrology.

  4. The different regulatory effects of p53 status on multidrug resistance are determined by autophagy in ovarian cancer cells.

    Science.gov (United States)

    Kong, Dejuan; Ma, Shumei; Liang, Bing; Yi, Heqing; Zhao, Yinlong; Xin, Rui; Cui, Li; Jia, Lili; Liu, Xin; Liu, Xiaodong

    2012-06-01

    Multidrug resistance (MDR) has become an obstacle for chemotherapy of cancer. p53 is reported to participate in the regulation of MDR, but the association between p53 status and MDR are complicated and conditional. It has been verified that apoptosis is not the only mechanism for MDR regulation by p53, the roles of autophagy in MDR is less studied. Human ovarian carcinoma cell lines SKOV3 and multidrug resistant phenotype SKVCR cells were used and wild-type p53 (wt p53) and mutant 175H constructs were introduced into cells to establish cell models with different p53 status by gene engineering, the sensitivity to vincristine (VCR), cisplatin (DDP), pirarubicin (THP) and etoposide (VP-16) were detected by MTT assay, Western blot and quantitative real-time PCR were used to detect the expression of protein and mRNA, especially, monodansylcadaverine (MDC) staining was used for autophagy rate, Hoechst 33342/propidium iodide (PI) were used to assess apoptosis and necrosis. SKVCR cells induced by VCR shown overexpression of P-glycoprotein (P-gp) and MDR, and also displayed an enhanced autophagy compared with parental SKOV3. Wt p53 and 175H has no influence on drug sensitivity in SKOV3, while both sensitized SKVCR cells to VCR, THP and VP-16, especially 175H. The introduction of wt p53-induced apoptosis only, while 175H trigged autophagic cell death, necrosis and apoptosis so as to reverse the MDR. The enhancement of autophagy in MDR cells allows to survive during chemotherapy stress, autophagy plays important role in wt p53 and mutant p53-immediated MDR. The different influence of p53 status on drug sensitivity hint the individual treatment strategies based on p53 status in patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  5. Systemic Monocyte Chemotactic Protein-1 Inhibition Modifies Renal Macrophages and Restores Glomerular Endothelial Glycocalyx and Barrier Function in Diabetic Nephropathy.

    Science.gov (United States)

    Boels, Margien G S; Koudijs, Angela; Avramut, M Cristina; Sol, Wendy M P J; Wang, Gangqi; van Oeveren-Rietdijk, Annemarie M; van Zonneveld, Anton Jan; de Boer, Hetty C; van der Vlag, Johan; van Kooten, Cees; Eulberg, Dirk; van den Berg, Bernard M; IJpelaar, Daphne H T; Rabelink, Ton J

    2017-11-01

    Inhibition of monocyte chemotactic protein-1 (MCP-1) with the Spiegelmer emapticap pegol (NOX-E36) shows long-lasting albuminuria-reducing effects in diabetic nephropathy. MCP-1 regulates inflammatory cell recruitment and differentiation of macrophages. Because the endothelial glycocalyx is also reduced in diabetic nephropathy, we hypothesized that MCP-1 inhibition restores glomerular barrier function through influencing macrophage cathepsin L secretion, thus reducing activation of the glycocalyx-degrading enzyme heparanase. Four weeks of treatment of diabetic Apoe knockout mice with the mouse-specific NOX-E36 attenuated albuminuria without any change in systemic hemodynamics, despite persistent loss of podocyte function. MCP-1 inhibition, however, increased glomerular endothelial glycocalyx coverage, with preservation of heparan sulfate. Mechanistically, both glomerular cathepsin L and heparanase expression were reduced. MCP-1 inhibition resulted in reduced CCR2-expressing Ly6C hi monocytes in the peripheral blood, without affecting overall number of kidney macrophages at the tissue level. However, the CD206 + /Mac3 + cell ratio, as an index of presence of anti-inflammatory macrophages, increased in diabetic mice after treatment. Functional analysis of isolated renal macrophages showed increased release of IL-10, whereas tumor necrosis factor and cathepsin L release was reduced, further confirming polarization of tissue macrophages toward an anti-inflammatory phenotype during mouse-specific NOX-E36 treatment. We show that MCP-1 inhibition restores glomerular endothelial glycocalyx and barrier function and reduces tissue inflammation in the presence of ongoing diabetic injury, suggesting a therapeutic potential for NOX-E36 in diabetic nephropathy. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  6. Autophagy in proximal tubules protects against acute kidney injury.

    Science.gov (United States)

    Jiang, Man; Wei, Qingqing; Dong, Guie; Komatsu, Masaaki; Su, Yunchao; Dong, Zheng

    2012-12-01

    Autophagy is induced in renal tubular cells during acute kidney injury; however, whether this is protective or injurious remains controversial. We address this question by pharmacologic and genetic blockade of autophagy using mouse models of cisplatin- and ischemia-reperfusion-induced acute kidney injury. Chloroquine, a pharmacological inhibitor of autophagy, blocked autophagic flux and enhanced acute kidney injury in both models. Rapamycin, however, activated autophagy and protected against cisplatin-induced acute kidney injury. We also established a renal proximal tubule-specific autophagy-related gene 7-knockout mouse model shown to be defective in both basal and cisplatin-induced autophagy in kidneys. Compared with wild-type littermates, these knockout mice were markedly more sensitive to cisplatin-induced acute kidney injury as indicated by renal functional loss, tissue damage, and apoptosis. Mechanistically, these knockout mice had heightened activation of p53 and c-Jun N terminal kinase, the signaling pathways contributing to cisplatin acute kidney injury. Proximal tubular cells isolated from the knockout mice were more sensitive to cisplatin-induced apoptosis than cells from wild-type mice. In addition, the knockout mice were more sensitive to renal ischemia-reperfusion injury than their wild-type littermates. Thus, our results establish a renoprotective role of tubular cell autophagy in acute kidney injury where it may interfere with cell killing mechanisms.

  7. Laser stimulation can activate autophagy in HeLa cells

    International Nuclear Information System (INIS)

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

    2014-01-01

    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 Ca 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.

  8. 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.

  9. Functions of autophagy in normal and diseased liver

    Science.gov (United States)

    Czaja, Mark J.; Ding, Wen-Xing; Donohue, Terrence M.; Friedman, Scott L.; Kim, Jae-Sung; Komatsu, Masaaki; Lemasters, John J.; Lemoine, Antoinette; Lin, Jiandie D.; Ou, Jing-hsiung James; Perlmutter, David H.; Randall, Glenn; Ray, Ratna B.; Tsung, Allan; Yin, Xiao-Ming

    2013-01-01

    Autophagy has emerged as a critical lysosomal pathway that maintains cell function and survival through the degradation of cellular components such as organelles and proteins. Investigations specifically employing the liver or hepatocytes as experimental models have contributed significantly to our current knowledge of autophagic regulation and function. The diverse cellular functions of autophagy, along with unique features of the liver and its principal cell type the hepatocyte, suggest that the liver is highly dependent on autophagy for both normal function and to prevent the development of disease states. However, instances have also been identified in which autophagy promotes pathological changes such as the development of hepatic fibrosis. Considerable evidence has accumulated that alterations in autophagy are an underlying mechanism of a number of common hepatic diseases including toxin-, drug- and ischemia/reperfusion-induced liver injury, fatty liver, viral hepatitis and hepatocellular carcinoma. This review summarizes recent advances in understanding the roles that autophagy plays in normal hepatic physiology and pathophysiology with the intent of furthering the development of autophagy-based therapies for human liver diseases. PMID:23774882

  10. 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.

  11. 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.

  12. Distinct Contributions of Autophagy Receptors in Measles Virus Replication.

    Science.gov (United States)

    Petkova, Denitsa S; Verlhac, Pauline; Rozières, Aurore; Baguet, Joël; Claviere, Mathieu; Kretz-Remy, Carole; Mahieux, Renaud; Viret, Christophe; Faure, Mathias

    2017-05-22

    Autophagy is a potent cell autonomous defense mechanism that engages the lysosomal pathway to fight intracellular pathogens. Several autophagy receptors can recognize invading pathogens in order to target them towards autophagy for their degradation after the fusion of pathogen-containing autophagosomes with lysosomes. However, numerous intracellular pathogens can avoid or exploit autophagy, among which is measles virus (MeV). This virus induces a complete autophagy flux, which is required to improve viral replication. We therefore asked how measles virus interferes with autophagy receptors during the course of infection. We report that in addition to NDP52/CALCOCO₂ and OPTINEURIN/OPTN, another autophagy receptor, namely T6BP/TAXIBP1, also regulates the maturation of autophagosomes by promoting their fusion with lysosomes, independently of any infection. Surprisingly, only two of these receptors, NDP52 and T6BP, impacted measles virus replication, although independently, and possibly through physical interaction with MeV proteins. Thus, our results suggest that a restricted set of autophagosomes is selectively exploited by measles virus to replicate in the course of infection.

  13. Autophagy and senescence: a partnership in search of definition.

    Science.gov (United States)

    Gewirtz, David A

    2013-05-01

    Autophagy and senescence share a number of characteristics, which suggests that both responses could serve to collaterally protect the cell from the toxicity of external stress such as radiation and chemotherapy and internal forms of stress such as telomere shortening and oncogene activation. Studies of oncogene activation in normal fibroblasts as well as exposure of tumor cells to chemotherapy have indicated that autophagy and senescence are closely related but not necessarily interdependent responses; specifically, interference with autophagy delays but does not abrogate senescence. The literature relating to this topic is inconclusive, with some reports appearing to be consistent with a direct relationship between autophagy and senescence and others indicative of an inverse relationship. Before this question can be resolved, additional studies will be necessary where autophagy is clearly inhibited by genetic silencing and where the temporal responses of both autophagy and senescence are monitored, preferably in cells that are intrinsically incapable of apoptosis or where apoptosis is suppressed. Understanding the nature of this relationship may provide needed insights relating to cytoprotective as well as potential cytotoxic functions of both autophagy and senescence.

  14. Autophagy as an Emerging Common Pathomechanism in Inherited Peripheral Neuropathies

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    Mansour Haidar

    2017-05-01

    Full Text Available The inherited peripheral neuropathies (IPNs comprise a growing list of genetically heterogeneous diseases. With mutations in more than 80 genes being reported to cause IPNs, a wide spectrum of functional consequences is expected to follow this genotypic diversity. Hence, the search for a common pathomechanism among the different phenotypes has become the holy grail of functional research into IPNs. During the last decade, studies on several affected genes have shown a direct and/or indirect correlation with autophagy. Autophagy, a cellular homeostatic process, is required for the removal of cell aggregates, long-lived proteins and dead organelles from the cell in double-membraned vesicles destined for the lysosomes. As an evolutionarily highly conserved process, autophagy is essential for the survival and proper functioning of the cell. Recently, neuronal cells have been shown to be particularly vulnerable to disruption of the autophagic pathway. Furthermore, autophagy has been shown to be affected in various common neurodegenerative diseases of both the central and the peripheral nervous system including Alzheimer’s, Parkinson’s, and Huntington’s diseases. In this review we provide an overview of the genes involved in hereditary neuropathies which are linked to autophagy and we propose the disruption of the autophagic flux as an emerging common pathomechanism. We also shed light on the different steps of the autophagy pathway linked to these genes. Finally, we review the concept of autophagy being a therapeutic target in IPNs, and the possibilities and challenges of this pathway-specific targeting.

  15. The regulation of autophagy differentially affects Trypanosoma cruzi metacyclogenesis

    Science.gov (United States)

    Vanrell, María Cristina; Losinno, Antonella Denisse; Cueto, Juan Agustín; Balcazar, Darío; Fraccaroli, Laura Virginia; Carrillo, Carolina

    2017-01-01

    Autophagy is a cellular process required for the removal of aged organelles and cytosolic components through lysosomal degradation. All types of eukaryotic cells from yeasts to mammalian cells have the machinery to activate autophagy as a result of many physiological and pathological situations. The most frequent stimulus of autophagy is starvation and the result, in this case, is the fast generation of utilizable food (e.g. amino acids and basic nutrients) to maintain the vital biological processes. In some organisms, starvation also triggers other associated processes such as differentiation. The protozoan parasite Trypanosoma cruzi undergoes a series of differentiation processes throughout its complex life cycle. Although not all autophagic genes have been identified in the T. cruzi genome, previous works have demonstrated the presence of essential autophagic-related proteins. Under starvation conditions, TcAtg8, which is the parasite homolog of Atg8/LC3 in other organisms, is located in autophagosome-like vesicles. In this work, we have characterized the autophagic pathway during T. cruzi differentiation from the epimastigote to metacyclic trypomastigote form, a process called metacyclogenesis. We demonstrated that autophagy is stimulated during metacyclogenesis and that the induction of autophagy promotes this process. Moreover, with exception of bafilomycin, other classical autophagy modulators have similar effects on T. cruzi autophagy. We also showed that spermidine and related polyamines can positively regulate parasite autophagy and differentiation. We concluded that both polyamine metabolism and autophagy are key processes during T. cruzi metacyclogenesis that could be exploited as drug targets to avoid the parasite cycle progression. PMID:29091711

  16. The regulation of autophagy differentially affects Trypanosoma cruzi metacyclogenesis.

    Directory of Open Access Journals (Sweden)

    María Cristina Vanrell

    2017-11-01

    Full Text Available Autophagy is a cellular process required for the removal of aged organelles and cytosolic components through lysosomal degradation. All types of eukaryotic cells from yeasts to mammalian cells have the machinery to activate autophagy as a result of many physiological and pathological situations. The most frequent stimulus of autophagy is starvation and the result, in this case, is the fast generation of utilizable food (e.g. amino acids and basic nutrients to maintain the vital biological processes. In some organisms, starvation also triggers other associated processes such as differentiation. The protozoan parasite Trypanosoma cruzi undergoes a series of differentiation processes throughout its complex life cycle. Although not all autophagic genes have been identified in the T. cruzi genome, previous works have demonstrated the presence of essential autophagic-related proteins. Under starvation conditions, TcAtg8, which is the parasite homolog of Atg8/LC3 in other organisms, is located in autophagosome-like vesicles. In this work, we have characterized the autophagic pathway during T. cruzi differentiation from the epimastigote to metacyclic trypomastigote form, a process called metacyclogenesis. We demonstrated that autophagy is stimulated during metacyclogenesis and that the induction of autophagy promotes this process. Moreover, with exception of bafilomycin, other classical autophagy modulators have similar effects on T. cruzi autophagy. We also showed that spermidine and related polyamines can positively regulate parasite autophagy and differentiation. We concluded that both polyamine metabolism and autophagy are key processes during T. cruzi metacyclogenesis that could be exploited as drug targets to avoid the parasite cycle progression.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. The regulation of autophagy differentially affects Trypanosoma cruzi metacyclogenesis.

    Science.gov (United States)

    Vanrell, María Cristina; Losinno, Antonella Denisse; Cueto, Juan Agustín; Balcazar, Darío; Fraccaroli, Laura Virginia; Carrillo, Carolina; Romano, Patricia Silvia

    2017-11-01

    Autophagy is a cellular process required for the removal of aged organelles and cytosolic components through lysosomal degradation. All types of eukaryotic cells from yeasts to mammalian cells have the machinery to activate autophagy as a result of many physiological and pathological situations. The most frequent stimulus of autophagy is starvation and the result, in this case, is the fast generation of utilizable food (e.g. amino acids and basic nutrients) to maintain the vital biological processes. In some organisms, starvation also triggers other associated processes such as differentiation. The protozoan parasite Trypanosoma cruzi undergoes a series of differentiation processes throughout its complex life cycle. Although not all autophagic genes have been identified in the T. cruzi genome, previous works have demonstrated the presence of essential autophagic-related proteins. Under starvation conditions, TcAtg8, which is the parasite homolog of Atg8/LC3 in other organisms, is located in autophagosome-like vesicles. In this work, we have characterized the autophagic pathway during T. cruzi differentiation from the epimastigote to metacyclic trypomastigote form, a process called metacyclogenesis. We demonstrated that autophagy is stimulated during metacyclogenesis and that the induction of autophagy promotes this process. Moreover, with exception of bafilomycin, other classical autophagy modulators have similar effects on T. cruzi autophagy. We also showed that spermidine and related polyamines can positively regulate parasite autophagy and differentiation. We concluded that both polyamine metabolism and autophagy are key processes during T. cruzi metacyclogenesis that could be exploited as drug targets to avoid the parasite cycle progression.

  19. 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.

  20. ER stress, autophagy, and RNA viruses

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    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.

  1. Autophagy in HCV Infection: Keeping Fat and Inflammation at Bay

    Directory of Open Access Journals (Sweden)

    Tiziana Vescovo

    2014-01-01

    Full Text Available Hepatitis C virus (HCV infection is one of the main causes of chronic liver disease. Viral persistence and pathogenesis rely mainly on the ability of HCV to deregulate specific host processes, including lipid metabolism and innate immunity. Recently, autophagy has emerged as a cellular pathway, playing a role in several aspects of HCV infection. This review summarizes current knowledge on the molecular mechanisms that link the HCV life cycle with autophagy machinery. In particular, we discuss the role of HCV/autophagy interaction in dysregulating inflammation and lipid homeostasis and its potential for translational applications in the treatment of HCV-infected patients.

  2. Multiscale and Multimodal Approaches to Study Autophagy in Model Plants

    Directory of Open Access Journals (Sweden)

    Jessica Marion

    2018-01-01

    Full Text Available Autophagy is a catabolic process used by eukaryotic cells to maintain or restore cellular and organismal homeostasis. A better understanding of autophagy in plant biology could lead to an improvement of the recycling processes of plant cells and thus contribute, for example, towards reducing the negative ecological consequences of nitrogen-based fertilizers in agriculture. It may also help to optimize plant adaptation to adverse biotic and abiotic conditions through appropriate plant breeding or genetic engineering to incorporate useful traits in relation to this catabolic pathway. In this review, we describe useful protocols for studying autophagy in the plant cell, taking into account some specificities of the plant model.

  3. Glomerular hyperfiltration in children with cancer: prevalence and a hypothesis

    Energy Technology Data Exchange (ETDEWEB)

    Kwatra, Neha S. [Children' s National Medical Center, Division of Diagnostic Imaging and Radiology, Washington, DC (United States); Boston Children' s Hospital, Department of Radiology, Boston, MA (United States); Meany, Holly J. [Children' s National Medical Center, Department of Hematology/Oncology, Washington, DC (United States); Ghelani, Sunil J. [Boston Children' s Hospital, Department of Cardiology, Boston, MA (United States); Zahavi, David [The Johns Hopkins University School of Medicine, Department of Pathology, Baltimore, MD (United States); Pandya, Nayan; Majd, Massoud [Children' s National Medical Center, Division of Diagnostic Imaging and Radiology, Washington, DC (United States)

    2017-02-15

    Glomerular hyperfiltration has recently been reported in children with malignancies and has been attributed to increased solute from breakdown of tumor tissues. To evaluate the prevalence of hyperfiltration in the pediatric oncology population and explore its pathophysiological mechanism. Tc-99 m diethylenetriaminepentaacetic acid (DTPA) glomerular filtration rate (GFR) examinations (437 studies) and medical records of 177 patients <21 years of age diagnosed with a malignancy between January 2005 and October 2013 were retrospectively reviewed. Hyperfiltration was defined as a GFR ≥ 160 ml/min/1.73 m{sup 2}. Seventy-seven (43.5%) patients had hyperfiltration in at least one GFR exam. A significantly higher percentage of patients with central nervous system (CNS) tumors (63.6%) had hyperfiltration when compared to other tumor types (27.3%, P < 0.001). No association was found between hyperfiltration and age, gender, race or bone marrow involvement. There was a significant trend toward decreasing hyperfiltration after the second cycle of chemotherapy (P = 0.006) and a significant increase in subjects with low GFR (<100 ml/min/1.73 m{sup 2}) with increasing number of cycles of chemotherapy (P = 0.005). Glomerular hyperfiltration is common in children with malignancies at diagnosis and during initial cycles of chemotherapy. It is particularly prevalent in patients with central nervous tumors, which are frequently smaller in volume. Therefore, the pathophysiological mechanism of hyperfiltration cannot be explained solely on the basis of large tumor volume and subsequent cell breakdown. We hypothesize that host hypermetabolic state plays an important role in pathophysiology of hyperfiltration. (orig.)

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

    International Nuclear Information System (INIS)

    Yang, Xiaojun; Zhong, Xiaomin; Tanyi, Janos L.; Shen, Jianfeng; Xu, Congjian; Gao, Peng; Zheng, Tim M.; DeMichele, Angela; Zhang, Lin

    2013-01-01

    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

  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. Glomerular sieving of high molecular weight proteins in proteinuric rats

    International Nuclear Information System (INIS)

    Bertolatus, J.A.; Abuyousef, M.; Hunsicker, L.G.

    1987-01-01

    To characterize the permeability of the glomerular capillary wall to high molecular weight proteins in normal and proteinuric rats, we determined the glomerular sieving coefficients (GSC) of radioiodinated marker proteins of known size and charge by means of a paired label, tissue accumulation method previously validated in this laboratory. In one group of rats (Series A) the GSCs of 125 I-anionic IgG (aIgG-molecular weight [mol wt] 150,000, pI 4.9) and 131 I-neutral IgG (nIgG-pI 7.4 to 7.6) were measured simultaneously. In Series B, the GSC of a second anionic marker, 131 I-human ceruloplasmin (Crp-mol wt 137,000, pI 4.9) was compared to that of 125 I-nIgG. As in the previous report, the labeled proteins were not degraded or deiodinated during the 20 minute clearance period for GSC determination. Within Series A and B, three subgroups of rats were studied: control saline-infused rats, rats made acutely proteinuric by infusion of the polycation hexadimethrine (HDM), and rats with chronic doxorubicin (Adriamycin-Adria) nephrosis. In the control rats, GSCs for the anionic markers aIgG (Series A) or Crp (Series B) were significantly greater than that of nIgG (both series). These large proteins crossed the filtration barrier by a different pathway from that available to smaller neutral molecules the size of albumin, which in our previous study had a much higher GSC than a native, anionic albumin marker. In a third group of control rats only (Series C), the GSCs of native anionic bovine albumin (BSA) and nIgG were compared directly. The GSC of BSA (0.0029) was only slightly larger than the GSC of nIgG (0.0025), indicating that most of the native albumin crosses the glomerular capillary wall via a nonselective pathway similar to that available to nIgG. The results in the control groups are compatible with recently-described heteroporous models of glomerular size selectivity

  7. 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.

  8. 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

  9. Determination of normal value of glomerular size in Chinese adults by different measurement methods.

    Science.gov (United States)

    Cheng, Hong; Dong, Hong-Rui; Lin, Rui-Qi; Sun, Li-Jun; Chen, Yi-Pu

    2012-07-01

      Identification of glomerulomegaly is a prerequisite for diagnosis of obesity-related glomerulopathy, so measurement of glomerular size is of critical importance.   A total 100 cases pathologically diagnosed as minor glomerular abnormalities or thin basement membrane nephropathy with normal body mass index and blood glucose level were selected as the normal value measurement group of glomerular size. The mean value of diameters of capillary tuft on the glomerular maximum profile was determined using the direct method and indirect method with the Motic Med 6.0 digital medical image analysis system. Meanwhile, 80 cases of different glomerular disease with normal body mass index and blood glucose level were also collected. Their glomerular diameters were measured and compared with those in the normal value measurement group.   The measurement results showed that gender and age had no effects on glomerular diameter. The normal value ranges of the diameter on glomerular maximum profile were as follows. (i) Pole-containing glomerulus (the glomerulus with vascular pole or/and urinary pole): direct method, 101.3-184.9 µm; indirect method, 100.3-183.5 µm. (ii) Pole-containing glomerulus plus non-pole glomerulus (the glomerulus without poles, the maximum profile of which was larger than that in the smallest pole-containing glomerulus): direct method, 108.3-185.9 µm; indirect method, 107.4-185.4 µm. The glomerular diameters of the 80 cases with different glomerular disease were all within the aforementioned normal value ranges.   Both methods used in the present study are feasible to measure the glomerular diameter and the normal value range of glomerular diameter in Chinese adults is established. © 2012 The Authors. Nephrology © 2012 Asian Pacific Society of Nephrology.

  10. The lack of autophagy triggers precocious activation of Notch signaling during Drosophila oogenesis.

    Science.gov (United States)

    Barth, Julia M I; Hafen, Ernst; Köhler, Katja

    2012-12-05

    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. 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. 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.

  11. Fentanyl induces autophagy via activation of the ROS/MAPK pathway and reduces the sensitivity of cisplatin in lung cancer cells.

    Science.gov (United States)

    Yao, Jiaqi; Ma, Chi; Gao, Wei; Liang, Jinxiao; Liu, Chang; Yang, Hongfang; Yan, Qiu; Wen, Qingping

    2016-12-01

    Cancer pain is the most common complication of lung carcinoma. Opioid agonist fentanyl is widely used for relieving pain in cancer patients, and cisplatin (DDP)‑based chemotherapy is commonly used for the treatment of advanced lung cancer; these two drugs are always used together in lung carcinoma patients. However, the mechanisms and related biological pathways by which fentanyl influences cisplatin sensitivity are relatively poorly reported. Here, we found that fentanyl reduces the sensitivity of cisplatin in human lung cancer cells and induces autophagy. Fentanyl induced reactive oxygen species (ROS) generation and JNK activation. N-acetyl‑L‑cysteine is a ROS scavenger and antioxidant, and the inhibition of JNK with SP600125 prevented fentanyl‑induced autophagy. We also found that 3-methyladenine (3-MA; an autophagy inhibitor) increased the sensitivity of DDP and weakened the inhibition of fentanyl. In conclusion, fentanyl reduces the sensitivity of cisplatin in lung cancer cells through the ROS-JNK-autophagy pathway, whereas the autophagy inhibitor 3-MA may weaken this effect.

  12. STAT3 balances myocyte hypertrophy vis-à-vis autophagy in response to Angiotensin II by modulating the AMPKα/mTOR axis.

    Science.gov (United States)

    Chen, Lei; Zhao, Lin; Samanta, Anweshan; Mahmoudi, Seyed Morteza; Buehler, Tanner; Cantilena, Amy; Vincent, Robert J; Girgis, Magdy; Breeden, Joshua; Asante, Samuel; Xuan, Yu-Ting; Dawn, Buddhadeb

    2017-01-01

    Signal transducers and activators of transcription 3 (STAT3) is known to participate in various cardiovascular signal transduction pathways, including those responsible for cardiac hypertrophy and cytoprotection. However, the role of STAT3 signaling in cardiomyocyte autophagy remains unclear. We tested the hypothesis that Angiotensin II (Ang II)-induced cardiomyocyte hypertrophy is effected, at least in part, through STAT3-mediated inhibition of cellular autophagy. In H9c2 cells, Ang II treatment resulted in STAT3 activation and cellular hypertrophy in a dose-dependent manner. Ang II enhanced autophagy, albeit without impacting AMPKα/mTOR signaling or cellular ADP/ATP ratio. Pharmacologic inhibition of STAT3 with WP1066 suppressed Ang II-induced myocyte hypertrophy and mRNA expression of hypertrophy-related genes ANP and β-MHC. These molecular events were recapitulated in cells with STAT3 knockdown. Genetic or pharmacologic inhibition of STAT3 significantly increased myocyte ADP/ATP ratio and enhanced autophagy through AMPKα/mTOR signaling. Pharmacologic activation and inhibition of AMPKα attenuated and exaggerated, respectively, the effects of Ang II on ANP and β-MHC gene expression, while concomitant inhibition of STAT3 accentuated the inhibition of hypertrophy. Together, these data indicate that novel nongenomic effects of STAT3 influence myocyte energy status and modulate AMPKα/mTOR signaling and autophagy to balance the transcriptional hypertrophic response to Ang II stimulation. These findings may have significant relevance for various cardiovascular pathological processes mediated by Ang II signaling.

  13. Podocyte-specific overexpression of metallothionein mitigates diabetic complications in the glomerular filtration barrier and glomerular histoarchitecture: a transmission electron microscopy stereometric analysis.

    Science.gov (United States)

    Carlson, Edward C; Chhoun, Jennifer M; Laturnus, Donna I; Bikash, K C; Berg, Brittany; Zheng, Shirong; Epstein, Paul N

    2013-02-01

    We previously demonstrated that cellular and extracellular components of the blood-urine barrier in renal glomeruli are susceptible to damage in OVE transgenic mice, a valuable model of human diabetic nephropathy that expresses profound albuminuria. To test our hypothesis that glomerular filtration barrier damage in OVE mice may be the result of oxidative insult to podocytes, 150-day-old bi-transgenic OVENmt diabetic mice that overexpress the antioxidant metallothionein specifically in podocytes were examined by enzyme-linked immunosorbent assay for albuminuria mitigation and by unbiased transmission electron microscopy (TEM) stereometry for protection from chronic structural diabetic complications. Although blood glucose and HbA(1c) levels were indistinguishable in OVE and OVENmt animals, albuminuria was significantly reduced (average >7-fold) in OVENmt mice through 8 months of age. Interestingly, the Nmt transgene provided significant glomerular protection against diabetic nephropathic complications outside of the podocyte. Glomerular filtration barrier damage was reduced in OVENmt mice, including significantly increased area occupied by endothelial luminal fenestrations (~13%), significantly reduced glomerular basement membrane (GBM) thickening (~17%) and significantly less podocyte effacement (~18%). In addition, OVENmt mice exhibited significantly reduced glomerular volume (~50%), fewer glomerular endothelial cells (~33%), fewer mesangial cells (~57%) and fewer total glomerular cells (~40%). These results provide evidence of oxidative damage to podocytes induces primary diabetic nephropathic features including severe and sustained albuminuria, specific glomerular filtration barrier damage and alterations in glomerular endothelial and mesangial cell number. Importantly, these diabetic complications are significantly mitigated by podocyte targeted metallothionein overexpression. Copyright © 2012 John Wiley & Sons, Ltd.

  14. Autophagy in Skeletal Muscle Homeostasis and in Muscular Dystrophies

    Directory of Open Access Journals (Sweden)

    Paolo Bonaldo

    2012-07-01

    Full Text Available Skeletal muscles are the agent of motion and one of the most important tissues responsible for the control of metabolism. The maintenance of muscle homeostasis is finely regulated by the balance between catabolic and anabolic process. Macroautophagy (or autophagy is a catabolic process that provides the degradation of protein aggregation and damaged organelles through the fusion between autophagosomes and lysosomes. Proper regulation of the autophagy flux is fundamental for the homeostasis of skeletal muscles during physiological situations and in response to stress. Defective as well as excessive autophagy is harmful for muscle health and has a pathogenic role in several forms of muscle diseases. This review will focus on the role of autophagy in muscle homeostasis and diseases.

  15. 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...

  16. Autophagy of mitochondria: a promising therapeutic target for neurodegenerative disease.

    Science.gov (United States)

    Kamat, Pradip K; Kalani, Anuradha; Kyles, Philip; Tyagi, Suresh C; Tyagi, Neetu

    2014-11-01

    The autophagic process is the only known mechanism for mitochondrial turnover and it has been speculated that dysfunction of autophagy may result in mitochondrial error and cellular stress. Emerging investigations have provided new understanding of how autophagy of mitochondria (also known as mitophagy) is associated with cellular oxidative stress and its impact on neurodegeneration. This impaired autophagic function may be considered as a possible mechanism in the pathogenesis of several neurodegenerative disorders including Parkinson's disease, Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington disease. It can be suggested that autophagy dysfunction along with oxidative stress is considered main events in neurodegenerative disorders. New therapeutic approaches have now begun to target mitochondria as a potential drug target. This review discusses evidence supporting the notion that oxidative stress and autophagy are intimately associated with neurodegenerative disease pathogenesis. This review also explores new approaches that can prevent mitochondrial dysfunction, improve neurodegenerative etiology, and also offer possible cures to the aforementioned neurodegenerative diseases.

  17. Autophagy as a mediator of life and death in plants.

    Science.gov (United States)

    Üstün, Suayib; Hafrén, Anders; Hofius, Daniel

    2017-12-01

    Autophagy is a major pathway for degradation and recycling of cytoplasmic material, including individual proteins, aggregates, and entire organelles. Autophagic processes serve mainly survival functions in cellular homeostasis, stress adaptation and immune responses but can also have death-promoting activities in different eukaryotic organisms. In plants, the role of autophagy in the regulation of programmed cell death (PCD) remained elusive and a subject of debate. More recent evidence, however, has resulted in the consensus that autophagy can either promote or restrict different forms of PCD. Here, we present latest advances in understanding the molecular mechanisms and functions of plant autophagy and discuss their implications for life and death decisions in the context of developmental and pathogen-induced PCD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Autophagy as a Therapeutic Target in Cardiovascular Disease

    Science.gov (United States)

    Nemchenko, Andriy; Chiong, Mario; Turer, Aslan; Lavandero, Sergio; Hill, Joseph A.

    2011-01-01

    The epidemic of heart failure continues apace, and development of novel therapies with clinical efficacy has lagged. Now, important insights into the molecular circuitry of cardiovascular autophagy have raised the prospect that this cellular pathway of protein quality control may be a target of clinical relevance. Whereas basal levels of autophagy are required for cell survival, excessive levels – or perhaps distinct forms of autophagic flux – contribute to disease pathogenesis. Our challenge will be to distinguish mechanisms that drive adaptive versus maladaptive autophagy and to manipulate those pathways for therapeutic gain. Recent evidence suggests this may be possible. Here, we review the fundamental biology of autophagy and its role in a variety of forms of cardiovascular disease. We discuss ways in which this evolutionarily conserved catabolic mechanism can be manipulated, discuss studies presently underway in heart disease, and provide our perspective on where this exciting field may lead in the future. PMID:21723289

  19. The Impact of Autophagy on Cardiovascular Senescence and Diseases.

    Science.gov (United States)

    Sasaki, Yuichi; Ikeda, Yoshiyuki; Iwabayashi, Masaaki; Akasaki, Yuichi; Ohishi, Mitsuru

    2017-10-21

    The risk of cardiovascular disease increases with age, causing chronic disability, morbidity, and mortality in the elderly. Cardiovascular aging and disease are characterized by heart failure, cardiac ischemia-reperfusion injury, cardiomyopathy, hypertension, arterial stiffness, and atherosclerosis. As a cell ages, damaged organelles and abnormal proteins accumulate. A system for removing these cytoplasmic substrates is essential for maintaining homeostasis. Autophagy assists tissue homeostasis by forming a pathway by which these substances are degraded. Growing evidence suggests that autophagy plays a role in age-related and disease states of the cardiovascular system, and it may even be effective in preventing or treating cardiovascular disease. On the other hand, overexpression of autophagy in the heart and arteries can produce detrimental effects. We summarize the current understanding of the close relationship between autophagy and cardiovascular senescence.

  20. Determination of Glomerular Filtration Rate by Using Gamma camera

    International Nuclear Information System (INIS)

    Amer, M.; Salim, D.

    2007-01-01

    Glomerular filtration rate (GFR) is a commonly accepted standard measure of renal function. It is routinely measured using tracers that are cleared exclusively by glomerular filtration. The aim of this study was to apply new nuclear medicine technique based on direct determination of clearance of a radioactive tracer provided that all the uptake compartments of the radioactive tracer should be included in the field of the view of the gamma camera. A total of 10 men and 7 women range from 27 to 64 years old were studied using dual head gamma camera. The data for clearance calculation comprises : (1) a transmission scan of part of the body using water phantom with a uniform distribution of the radioisotope , (2) the background corrected activity curves in the anterior and posterior views over all uptake compartments following the injection of radioactive tracer, and (3) the activity of radioactive tracer in two blood samples drawn during the examination. The results for GFR above 30 ml min -1 , the regression line of GFR by using simplified multiple sample method versus GFR in gamma camera method were not significantly different from the line of identity. The reliability of the gamma camera method was about 16%, 12 % and 8% for GFR values of 30, 60 and 100 ml min-1. Therefore, the reliability of the gamma camera and the simplified multiple sample method for prediction of GFR were almost the same.

  1. Autophagy Regulates Colistin-Induced Apoptosis in PC-12 Cells

    Science.gov (United States)

    Zhang, Ling; Zhao, Yonghao; Ding, Wenjian; Jiang, Guozheng; Lu, Ziyin; Li, Li; Wang, Jinli

    2015-01-01

    Colistin is a cyclic cationic polypeptide antibiotic with activity against multidrug-resistant Gram-negative bacteria. Our recent study demonstrated that colistin induces apoptosis in primary chick cortex neurons and PC-12 cells. Although apoptosis and autophagy have different impacts on cell fate, there is a complex interaction between them. Autophagy plays an important role as a homeostasis regulator by removing excessive or unnecessary proteins and damaged organelles. The aim of the present study was to investigate the modulation of autophagy and apoptosis regulation in PC-12 cells in response to colistin treatment. PC-12 cells were exposed to colistin (125 to 250 μg/ml), and autophagy was detected by visualization of monodansylcadaverine (MDC)-labeled vacuoles, LC3 (microtubule-associated protein 1 light chain 3) immunofluorescence microscopic examination, and Western blotting. Apoptosis was measured by flow cytometry, Hoechst 33258 staining, and Western blotting. Autophagosomes were observed after treatment with colistin for 12 h, and the levels of LC3-II gene expression were determined; observation and protein levels both indicated that colistin induced a high level of autophagy. Colistin treatment also led to apoptosis in PC-12 cells, and the level of caspase-3 expression increased over the 24-h period. Pretreatment of cells with 3-methyladenine (3-MA) increased colistin toxicity in PC-12 cells remarkably. However, rapamycin treatment significantly increased the expression levels of LC3-II and beclin 1 and decreased the rate of apoptosis of PC-12 cells. Our results demonstrate that colistin induced autophagy and apoptosis in PC-12 cells and that the latter was affected by the regulation of autophagy. It is very likely that autophagy plays a protective role in the reduction of colistin-induced cytotoxicity in neurons. PMID:25645826

  2. 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.

  3. Thermogenic activation represses autophagy in brown adipose tissue.

    Science.gov (United States)

    Cairó, M; Villarroya, J; Cereijo, R; Campderrós, L; Giralt, M; Villarroya, F

    2016-10-01

    Brown adipose tissue (BAT) thermogenesis is an adaptive process, essential for energy expenditure and involved in the control of obesity. Obesity is associated with abnormally increased autophagy in white adipose tissue. Autophagy has been proposed as relevant for brown-vs-white adipocyte differentiation; however, its role in the response of BAT to thermogenic activation is unknown. The effects of thermogenic activation on autophagy in BAT were analyzed in vivo by exposing mice to 24 h cold condition. The effects of norepinephrine (NE), cAMP and modulators of lysosomal activity were determined in differentiated brown adipocytes in the primary culture. Transcript expression was quantified by real-time PCR, and specific proteins were determined by immunoblot. Transmission electron microscopy, as well as confocal microscopy analysis after incubation with specific antibodies or reagents coupled to fluorescent emission, were performed in BAT and cultured brown adipocytes, respectively. Autophagy is repressed in association with cold-induced thermogenic activation of BAT in mice. This effect was mimicked by NE action in brown adipocytes, acting mainly through a cAMP-dependent protein kinase A pathway. Inhibition of autophagy in brown adipocytes leads to an increase in UCP1 protein and uncoupled respiration, suggesting a repressing role for autophagy in relation to the activity of BAT thermogenic machinery. Under basal conditions, brown adipocytes show signs of active lipophagy, which is suppressed by a cAMP-mediated thermogenic stimulus. Our results show a noradrenergic-mediated inverse relationship between autophagy and thermogenic activity in BAT and point toward autophagy repression as a component of brown adipocyte adaptive mechanisms to activate thermogenesis.

  4. p53-Mediated Molecular Control of Autophagy in Tumor Cells

    Directory of Open Access Journals (Sweden)

    Maria Mrakovcic

    2018-03-01

    Full Text Available Autophagy is an indispensable mechanism of the eukaryotic cell, facilitating the removal and renewal of cellular components and thereby balancing the cell’s energy consumption and homeostasis. Deregulation of autophagy is now regarded as one of the characteristic key features contributing to the development of tumors. In recent years, the suppression of autophagy in combination with chemotherapeutic treatment has been approached as a novel therapy in cancer treatment. However, depending on the type of cancer and context, interference with the autophagic machinery can either promote or disrupt tumorigenesis. Therefore, disclosure of the major signaling pathways that regulate autophagy and control tumorigenesis is crucial. To date, several tumor suppressor proteins and oncogenes have emerged as eminent regulators of autophagy whose depletion or mutation favor tumor formation. The mammalian cell “janitor” p53 belongs to one of these tumor suppressors that are most commonly mutated in human tumors. Experimental evidence over the last decade convincingly reports that p53 can act as either an activator or an inhibitor of autophagy depending on its subcellular localization and its mode of action. This finding gains particular significance as p53 deficiency or mutant variants of p53 that accumulate in the cytoplasm of tumor cells enable activation of autophagy. Accordingly, we recently identified p53 as a molecular hub that regulates autophagy and apoptosis in histone deacetylase inhibitor-treated uterine sarcoma cells. In light of this novel experimental evidence, in this review, we focus on p53 signaling as a mediator of the autophagic pathway in tumor cells.

  5. Autophagy Proteins in Viral Exocytosis and Anti-Viral Immune Responses

    Directory of Open Access Journals (Sweden)

    Christian Münz

    2017-10-01

    Full Text Available Abstract: Autophagy-related (Atg gene-encoded proteins were originally described for their crucial role in macroautophagy, a catabolic pathway for cytoplasmic constituent degradation in lysosomes. Recently it has become clear that modules of this machinery can also be used to influence endo- and exocytosis. This mini review discusses how these alternative Atg functions support virus replication and viral antigen presentation on major histocompatibility (MHC class I and II molecules. A better understanding of the modular use of the macroautophagy machinery might enable us to manipulate these alternative functions of Atg proteins during anti-viral therapies and to attenuate virus-induced immune pathologies.

  6. Characterization of a novel autophagy-specific gene, ATG29

    International Nuclear Information System (INIS)

    Kawamata, Tomoko; Kamada, Yoshiaki; Suzuki, Kuninori; Kuboshima, Norihiro; Akimatsu, Hiroshi; Ota, Shinichi; Ohsumi, Mariko; Ohsumi, Yoshinori

    2005-01-01

    Autophagy is a process whereby cytoplasmic proteins and organelles are sequestered for bulk degradation in the vacuole/lysosome. At present, 16 ATG genes have been found that are essential for autophagosome formation in the yeast Saccharomyces cerevisiae. Most of these genes are also involved in the cytoplasm to vacuole transport pathway, which shares machinery with autophagy. Most Atg proteins are colocalized at the pre-autophagosomal structure (PAS), from which the autophagosome is thought to originate, but the precise mechanism of autophagy remains poorly understood. During a genetic screen aimed to obtain novel gene(s) required for autophagy, we identified a novel ORF, ATG29/YPL166w. atg29Δ cells were sensitive to starvation and induction of autophagy was severely retarded. However, the Cvt pathway operated normally. Therefore, ATG29 is an ATG gene specifically required for autophagy. Additionally, an Atg29-GFP fusion protein was observed to localize to the PAS. From these results, we propose that Atg29 functions in autophagosome formation at the PAS in collaboration with other Atg proteins

  7. Autophagy, Warburg, and Warburg Reverse Effects in Human Cancer

    Directory of Open Access Journals (Sweden)

    Claudio D. Gonzalez

    2014-01-01

    Full Text Available Autophagy is a highly regulated-cell pathway for degrading long-lived proteins as well as for clearing cytoplasmic organelles. Autophagy is a key contributor to cellular homeostasis and metabolism. Warburg hypothesized that cancer growth is frequently associated with a deviation of a set of energy generation mechanisms to a nonoxidative breakdown of glucose. This cellular phenomenon seems to rely on a respiratory impairment, linked to mitochondrial dysfunction. This mitochondrial dysfunction results in a switch to anaerobic glycolysis. It has been recently suggested that epithelial cancer cells may induce the Warburg effect in neighboring stromal fibroblasts in which autophagy was activated. These series of observations drove to the proposal of a putative reverse Warburg effect of pathophysiological relevance for, at least, some tumor phenotypes. In this review we introduce the autophagy process and its regulation and its selective pathways and role in cancer cell metabolism. We define and describe the Warburg effect and the newly suggested “reverse” hypothesis. We also discuss the potential value of modulating autophagy with several pharmacological agents able to modify the Warburg effect. The association of the Warburg effect in cancer and stromal cells to tumor-related autophagy may be of relevance for further development of experimental therapeutics as well as for cancer prevention.

  8. Integrative metabolomics as emerging tool to study autophagy regulation

    Directory of Open Access Journals (Sweden)

    Sarah Stryeck

    2017-07-01

    Full Text Available Recent technological developments in metabolomics research have enabled in-depth characterization of complex metabolite mixtures in a wide range of biological, biomedical, environmental, agricultural, and nutritional research fields. Nuclear magnetic resonance spectroscopy and mass spectrometry are the two main platforms for performing metabolomics studies. Given their broad applicability and the systemic insight into metabolism that can be ob-tained it is not surprising that metabolomics becomes increasingly popular in basic biological research. In this review, we provide an overview on key me-tabolites, recent studies, and future opportunities for metabolomics in stud-ying autophagy regulation. Metabolites play a pivotal role in autophagy regulation and are therefore key targets for autophagy research. Given the recent success of metabolomics, it can be expected that metabolomics ap-proaches will contribute significantly to deciphering the complex regulatory mechanisms involved in autophagy in the near future and promote under-standing of autophagy and autophagy-related diseases in living cells and or-ganisms.

  9. 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. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  10. 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

  11. Tenovin-6 impairs autophagy by inhibiting autophagic flux.

    Science.gov (United States)

    Yuan, Hongfeng; Tan, Brandon; Gao, Shou-Jiang

    2017-02-09

    Tenovin-6 has attracted significant interest because it activates p53 and inhibits sirtuins. It has anti-neoplastic effects on multiple hematopoietic malignancies and solid tumors in both in vitro and in vivo studies. Tenovin-6 was recently shown to impair the autophagy pathway in chronic lymphocytic leukemia cells and pediatric soft tissue sarcoma cells. However, whether tenovin-6 has a general inhibitory effect on autophagy and whether there is any involvement with SIRT1 and p53, both of which are regulators of the autophagy pathway, remain unclear. In this study, we have demonstrated that tenovin-6 increases microtubule-associated protein 1 light chain 3 (LC3-II) level in diverse cell types in a time- and dose-dependent manner. Mechanistically, the increase of LC3-II by tenovin-6 is caused by inhibition of the classical autophagy pathway via impairing lysosomal function without affecting the fusion between autophagosomes and lysosomes. Furthermore, we have revealed that tenovin-6 activation of p53 is cell type dependent, and tenovin-6 inhibition of autophagy is not dependent on its regulatory functions on p53 and SIRT1. Our results have shown that tenovin-6 is a potent autophagy inhibitor, and raised the precaution in interpreting results where tenovin-6 is used as an inhibitor of SIRT1.

  12. Overweight in elderly people induces impaired autophagy in skeletal muscle.

    Science.gov (United States)

    Potes, Yaiza; de Luxán-Delgado, Beatriz; Rodriguez-González, Susana; Guimarães, Marcela Rodrigues Moreira; Solano, Juan J; Fernández-Fernández, María; Bermúdez, Manuel; Boga, Jose A; Vega-Naredo, Ignacio; Coto-Montes, Ana

    2017-09-01

    Sarcopenia is the gradual loss of skeletal muscle mass, strength and quality associated with aging. Changes in body composition, especially in skeletal muscle and fat mass are crucial steps in the development of chronic diseases. We studied the effect of overweight on skeletal muscle tissue in elderly people without reaching obesity to prevent this extreme situation. Overweight induces a progressive protein breakdown reflected as a progressive withdrawal of anabolism against the promoted catabolic state leading to muscle wasting. Protein turnover is regulated by a network of signaling pathways. Muscle damage derived from overweight displayed by oxidative and endoplasmic reticulum (ER) stress induces inflammation and insulin resistance and forces the muscle to increase requirements from autophagy mechanisms. Our findings showed that failure of autophagy in the elderly deprives it to deal with the cell damage caused by overweight. This insufficiently efficient autophagy leads to an accumulation of p62 and NBR1, which are robust markers of protein aggregations. This impaired autophagy affects myogenesis activity. Depletion of myogenic regulatory factors (MRFs) without links to variations in myostatin levels in overweight patients suggest a possible reduction of satellite cells in muscle tissue, which contributes to declined muscle quality. This discovery has important implications that improve the understanding of aged-related atrophy caused by overweight and demonstrates how impaired autophagy is one of the main responsible mechanisms that aggravate muscle wasting. Therefore, autophagy could be an interesting target for therapeutic interventions in humans against muscle impairment diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. 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.

  14. Roles of Autophagy Induced by Natural Compounds in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    V. Naponelli

    2015-01-01

    Full Text Available Autophagy is a homeostatic mechanism through which intracellular organelles and proteins are degraded and recycled in response to increased metabolic demand or stress. Autophagy dysfunction is often associated with many diseases, including cancer. Because of its role in tumorigenesis, autophagy can represent a new therapeutic target for cancer treatment. Prostate cancer (PCa is one of the most common cancers in aged men. The evidence on alterations of autophagy related genes and/or protein levels in PCa cells suggests a potential implication of autophagy in PCa onset and progression. The use of natural compounds, characterized by low toxicity to normal tissue associated with specific anticancer effects at physiological levels in vivo, is receiving increasing attention for prevention and/or treatment of PCa. Understanding the mechanism of action of these compounds could be crucial for the development of new therapeutic or chemopreventive options. In this review we focus on the current evidence showing the capacity of natural compounds to exert their action through autophagy modulation in PCa cells.

  15. Cytoplasmic sphingosine-1-phosphate pathway modulates neuronal autophagy.

    Science.gov (United States)

    Moruno Manchon, Jose Felix; Uzor, Ndidi-Ese; Dabaghian, Yuri; Furr-Stimming, Erin E; Finkbeiner, Steven; Tsvetkov, Andrey S

    2015-10-19

    Autophagy is an important homeostatic mechanism that eliminates long-lived proteins, protein aggregates and damaged organelles. Its dysregulation is involved in many neurodegenerative disorders. Autophagy is therefore a promising target for blunting neurodegeneration. We searched for novel autophagic pathways in primary neurons and identified the cytosolic sphingosine-1-phosphate (S1P) pathway as a regulator of neuronal autophagy. S1P, a bioactive lipid generated by sphingosine kinase 1 (SK1) in the cytoplasm, is implicated in cell survival. We found that SK1 enhances flux through autophagy and that S1P-metabolizing enzymes decrease this flux. When autophagy is stimulated, SK1 relocalizes to endosomes/autophagosomes in neurons. Expression of a dominant-negative form of SK1 inhibits autophagosome synthesis. In a neuron model of Huntington's disease, pharmacologically inhibiting S1P-lyase protected neurons from mutant huntingtin-induced neurotoxicity. These results identify the S1P pathway as a novel regulator of neuronal autophagy and provide a new target for developing therapies for neurodegenerative disorders.

  16. 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.

  17. Role of Autophagy in HIV Pathogenesis and Drug Abuse.

    Science.gov (United States)

    Cao, Lu; Glazyrin, Alexey; Kumar, Santosh; Kumar, Anil

    2017-10-01

    Autophagy is a highly regulated process in which excessive cytoplasmic materials are captured and degraded during deprivation conditions. The unique nature of autophagy that clears invasive microorganisms has made it an important cellular defense mechanism in a variety of clinical situations. In recent years, it has become increasingly clear that autophagy is extensively involved in the pathology of HIV-1. To ensure survival of the virus, HIV-1 viral proteins modulate and utilize the autophagy pathway so that biosynthesis of the virus is maximized. At the same time, the abuse of illicit drugs such as methamphetamine, cocaine, morphine, and alcohol is thought to be a significant risk factor for the acquirement and progression of HIV-1. During drug-induced toxicity, autophagic activity has been proved to be altered in various cell types. Here, we review the current literature on the interaction between autophagy, HIV-1, and drug abuse and discuss the complex role of autophagy during HIV-1 pathogenesis in co-exposure to illicit drugs.

  18. Cell "self-eating" (autophagy) mechanism in Alzheimer's disease.

    Science.gov (United States)

    Funderburk, Sarah F; Marcellino, Bridget K; Yue, Zhenyu

    2010-01-01

    The autophagy pathway is the major degradation pathway of the cell for long-lived proteins and organelles. Dysfunction of autophagy has been linked to several neurodegenerative disorders that are associated with an accumulation of misfolded protein aggregates. Alzheimer's disease, the most common neurodegenerative disorder, is characterized by 2 aggregate forms, tau tangles and amyloid-beta plaques. Autophagy has been linked to Alzheimer's disease pathogenesis through its merger with the endosomal-lysosomal system, which has been shown to play a role in the formation of the latter amyloid-beta plaques. However, the precise role of autophagy in Alzheimer's disease pathogenesis is still under contention. One hypothesis is that aberrant autophagy induction results in an accumulation of autophagic vacuoles containing amyloid-beta and the components necessary for its generation, whereas other evidence points to impaired autophagic clearance or even an overall reduction in autophagic activity playing a role in Alzheimer's disease pathogenesis. In this review, we discuss the current evidence linking autophagy to Alzheimer's disease as well as the uncertainty over the exact role and level of autophagic regulation in the pathogenic mechanism of Alzheimer's disease. (c) 2010 Mount Sinai School of Medicine.

  19. 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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. Targeting autophagy in cancer management – strategies and developments

    International Nuclear Information System (INIS)

    Ozpolat, Bulent; Benbrook, Doris M

    2015-01-01

    Autophagy is a highly regulated catabolic process involving lysosomal degradation of intracellular components, damaged organelles, misfolded proteins, and toxic aggregates, reducing oxidative stress and protecting cells from damage. The process is also induced in response to various conditions, including nutrient deprivation, metabolic stress, hypoxia, anticancer therapeutics, and radiation therapy to adapt cellular conditions for survival. Autophagy can function as a tumor suppressor mechanism in normal cells and dysregulation of this process (ie, monoallelic Beclin-1 deletion) may lead to malignant transformation and carcinogenesis. In tumors, autophagy is thought to promote tumor growth and progression by helping cells to adapt and survive in metabolically-challenged and harsh tumor microenvironments (ie, hypoxia and acidity). Recent in vitro and in vivo studies in preclinical models suggested that modulation of autophagy can be used as a therapeutic modality to enhance the efficacy of conventional therapies, including chemo and radiation therapy. Currently, more than 30 clinical trials are investigating the effects of autophagy inhibition in combination with cytotoxic chemotherapies and targeted agents in various cancers. In this review, we will discuss the role, molecular mechanism, and regulation of autophagy, while targeting this process as a novel therapeutic modality, in various cancers

  1. Characterization of glomerular extracellular matrix by proteomic analysis of laser captured microdissected glomeruli

    Science.gov (United States)

    Hobeika, Liliane; Barati, Michelle T.; Caster, Dawn J.; McLeish, Kenneth R.; Merchant, Michael L.

    2016-01-01

    Abnormal extracellular matrix (ECM) remodeling is a prominent feature of many glomerular diseases and is a final common pathway of glomerular injury. However, changes in ECM composition accompanying disease-related remodeling are unknown. The physical properties of ECM create challenges for characterization of composition using standard protein extraction techniques, as the insoluble components of ECM are frequently discarded and many ECM proteins are in low abundance compared to other cell proteins. Prior proteomic studies defining normal ECM composition used a large number of glomeruli isolated from human kidneys retrieved for transplantation or by nephrectomy for cancer. Here we examined the ability to identify ECM proteins by mass spectrometry using glomerular sections compatible with that available from standard renal biopsy specimens. Proteins were classified as ECM by comparison to the Matrisome database and previously identified glomerular ECM proteins. Optimal ECM protein identification resulted from sequential decellularization and protein extraction of 100 human glomerular sections isolated by laser capture microdissection from either frozen or formalin fixed paraffin embedded tissue. In total, 147 ECM proteins were identified, including the majority of structural and GBM proteins previously identified along with a number of matrix and glomerular basement membrane proteins not previously associated with glomeruli. Thus, our study demonstrates the feasibility of proteomic analysis of glomerular ECM from retrieved glomerular sections isolated from renal biopsy tissue and expands the list of known ECM proteins in glomeruli. PMID:27988214

  2. Nucleosomes and histones are present in glomerular deposits in human lupus nephritis

    NARCIS (Netherlands)

    vanBruggen, MCJ; Kramers, C; Walgreen, B; Elema, JD; Kallenberg, CGM; vandenBorn, J; Smeenk, RJT; Assmann, KJM; Muller, S; Monestier, M; Berden, JHM

    Background. Recently we showed that antinuclear autoantibodies complexed to nucleosomes can bind to heparan sulphate (HS) in the glomerular basement membrane (GEM) via the histone part of the nucleosome. Histones have been identified in glomerular deposits in human and murine lupus nephritis. In

  3. 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

  4. Autophagy is essential for the differentiation of porcine PSCs into insulin-producing cells.

    Science.gov (United States)

    Ren, Lipeng; Yang, Hong; Cui, Yanhua; Xu, Shuanshuan; Sun, Fen; Tian, Na; Hua, Jinlian; Peng, Sha

    2017-07-01

    Porcine pancreatic stem cells (PSCs) are seed cells with potential use for diabetes treatment. Stem cell differentiation requires strict control of protein turnover and lysosomal digestion of organelles. Autophagy is a highly conserved process that controls the turnover of organelles and proteins within cells and contributes to the balance of cellular components. However, whether autophagy plays roles in PSC differentiation remains unknown. In this study, we successfully induced porcine PSCs into insulin-producing cells and found that autophagy was activated during the second induction stage. Inhibition of autophagy in the second stage resulted in reduced differentiational efficiency and impaired glucose-stimulated insulin secretion. Moreover, the expression of active β-catenin increased while autophagy was activated but was suppressed when autophagy was inhibited. Therefore, autophagy is essential to the formation of insulin-producing cells, and the effects of autophagy on differentiation may be regulated by canonical Wnt signalling pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. 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...

  6. 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.

  7. Glomerular diseases and cancer: evaluation of underlying malignancy.

    Science.gov (United States)

    Pani, Antonello; Porta, Camillo; Cosmai, Laura; Melis, Patrizia; Floris, Matteo; Piras, Doloretta; Gallieni, Maurizio; Rosner, Mitchell; Ponticelli, Claudio

    2016-04-01

    Onconephrology is an emerging medical subspecialty focused on the numerous interconnections between cancer and kidney diseases. Patient with malignancies commonly experience kidney problems including acute kidney injury, tumor lysis syndrome, fluid and electrolyte disorders and chronic kidney disease, often as a consequence of the anti-cancer treatment. Conversely, a number of glomerulopathies, tubulopathies and vascular renal diseases can early signal the presence of an underlying cancer. Furthermore, the administration of immunosuppressive drugs, especially cytotoxic drugs and calcineurin inhibitors, may strongly impair the immune response increasing the risk of cancer. The objective of this review article is to: (i) discuss paraneoplastic glomerular disease, (ii) review cancer as an adverse effect of immunosuppressive agents used to treat glomerulopathies, and (iii) in the absence of international approved guidelines, propose a screening program based on expert opinion aimed at guiding nephrologists to early detect malignancies during their clinical practice.

  8. The Effects of Kaempferol-Inhibited Autophagy on Osteoclast Formation.

    Science.gov (United States)

    Kim, Chang-Ju; Shin, Sang-Hun; Kim, Bok-Joo; Kim, Chul-Hoon; Kim, Jung-Han; Kang, Hae-Mi; Park, Bong-Soo; Kim, In-Ryoung

    2018-01-02

    Kaempferol, a flavonoid compound, is derived from the rhizome of Kaempferia galanga L ., which is used in traditional medicine in Asia. Autophagy has pleiotropic functions that are involved in cell growth, survival, nutrient supply under starvation, defense against pathogens, and antigen presentation. There are many studies dealing with the inhibitory effects of natural flavonoids in bone resorption. However, no studies have explained the relationship between the autophagic and inhibitory processes of osteoclastogenesis by natural flavonoids. The present study was undertaken to investigate the inhibitory effects of osteoclastogenesis through the autophagy inhibition process stimulated by kaempferol in murin macrophage (RAW 264.7) cells. The cytotoxic effect of Kaempferol was investigated by MTT assay. The osteoclast differentiation and autophagic process were confirmed via tartrate-resistant acid phosphatase (TRAP) staining, pit formation assay, western blot, and real-time PCR. Kaempferol controlled the expression of autophagy-related factors and in particular, it strongly inhibited the expression of p62/SQSTM1. In the western blot and real time-PCR analysis, when autophagy was suppressed with the application of 3-Methyladenine (3-MA) only, osteoclast and apoptosis related factors were not significantly affected. However, we found that after cells were treated with kaempferol, these factors inhibited autophagy and activated apoptosis. Therefore, we presume that kaempferol-inhibited autophagy activated apoptosis by degradation of p62/SQSTM1. Further study of the p62/SQSTM1 gene as a target in the autophagy mechanism, may help to delineate the potential role of kaempferol in the treatment of bone metabolism disorders.

  9. 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.

  10. Glomerular and Tubular Damage Markers in Individuals with Progressive Albuminuria

    Science.gov (United States)

    Nauta, Ferdau L.; Scheven, Lieneke; Meijer, Esther; van Oeveren, Wim; de Jong, Paul E.; Bakker, Stephan J.L.

    2013-01-01

    Summary Background and objectives Albuminuria is associated with risk for renal and cardiovascular disease. It is difficult to predict which persons will progress in albuminuria. This study investigated whether assessment of urinary markers associated with damage to different parts of the nephron may help identify individuals that will progress in albuminuria. Design, setting, participants, & measurements Individuals were selected from a prospective community-based cohort study with serial follow-up and defined as “progressors” if they belonged to the quintile of participants with the most rapid annual increase in albuminuria, and reached an albuminuria ≥150 mg/d during follow-up. Patients with known renal disease or macroalbuminuria at baseline were excluded. Each progressor was matched to two control participants, based on baseline albuminuria, age, and sex. Furthermore, damage markers were measured in a separate set of healthy individuals. Results After a median follow-up of 8.6 years, 183 of 8394 participants met the criteria for progressive albuminuria. Baseline clinical characteristics were comparable between progressors and matched controls (n=366). Both had higher baseline albuminuria than the overall population. Urinary excretion of the glomerular damage marker IgG was significantly higher in progressors, whereas urinary excretion of proximal tubular damage markers and inflammatory markers was lower in these individuals compared with controls. Healthy individuals (n=109) had the lowest values for all urinary damage markers measured. Conclusions These data suggest that albuminuria associated with markers of glomerular damage is more likely to progress, whereas albuminuria associated with markers of tubulointerstitial damage is more likely to remain stable. PMID:23539232

  11. Glomerular diseases associated with HBV and HCV infection

    Directory of Open Access Journals (Sweden)

    Boriana Kiperova

    2014-03-01

    Full Text Available Hepatitis B and C viruses are human pathogens of major significance. Their extrahepatic manifestations are global health problem. HBV is a well-known cause of membranous nephropathy, membranoproliferative GN and IgA nephropathy, frequently in Asian populations. Polyarteritis nodosa is a rare, but serious systemic complication of chronic HBV. Immunosuppressive therapy in HBV-related GN is not recommended. Interferon alpha treatment produces sustained remission of porteinuria, often associated with clearance of HBeAg and/or HBsAg, however, it has many side effects. Compared to interferon, nucleos(tide analogues offer some advantages. These antiviral agents suppress HBV replication through their inhibitory effect on viral DNA polymerase. They have convenient administration and high tolerability. Lamivudine is well tolerated and safe in long-term studies, but the resistance of HBV is an escalating problem. The resistance to newer polymerase inhibitors Entecavir and Tenofovir is significantly lower. Hepatitis C virus causes cryoglobulinemia-mediated glomerulonephritis and other immune complex forms of GN. The renal manifestations are usually associated with long-lasting HCV infection. HCV glomerular disease is more frequent in adult males, and often leads to chronic renal insufficiency. The first line treatment in patients with mild to moderate clinical and histological kidney damage is the antiviral therapy with pegylated INF alpha and ribavirin. In case of severe HCV-associated cryoglobulinemic GN - nephrotic syndrome, nephritic syndrome and/or progressive renal failure, high activity score of glomerulonephritis on light microscopy, the initial treatment might consist of sequential administration of antiviral and immunosuppressive agents (corticosteroids, cyclophosphamide and plasma exchange, or rituximab. The treatment of HCV-related glomerular disease is still under debate and based on scant experimental evidence. Large randomized and controlled

  12. Glomerular damage as a predictor of renal allograft loss

    Directory of Open Access Journals (Sweden)

    G. Moscoso-Solorzano

    2010-06-01

    Full Text Available Interstitial fibrosis and tubular atrophy (IF/TA are the most common cause of renal graft failure. Chronic transplant glomerulopathy (CTG is present in approximately 1.5-3.0% of all renal grafts. We retrospectively studied the contribution of CTG and recurrent post-transplant glomerulopathies (RGN to graft loss. We analyzed 123 patients with chronic renal allograft dysfunction and divided them into three groups: CTG (N = 37, RGN (N = 21, and IF/TA (N = 65. Demographic data were analyzed and the variables related to graft function identified by statistical methods. CTG had a significantly lower allograft survival than IF/TA. In a multivariate analysis, protective factors for allograft outcomes were: use of angiotensin-converting enzyme inhibitor (ACEI; hazard ratio (HR = 0.12, P = 0.001, mycophenolate mofetil (MMF; HR = 0.17, P = 0.026, hepatitis C virus (HR = 7.29, P = 0.003, delayed graft function (HR = 5.32, P = 0.016, serum creatinine ≥1.5 mg/dL at the 1st year post-transplant (HR = 0.20, P = 0.011, and proteinuria ≥0.5 g/24 h at the 1st year post-transplant (HR = 0.14, P = 0.004. The presence of glomerular damage is a risk factor for allograft loss (HR = 4.55, P = 0.015. The presence of some degree of chronic glomerular damage in addition to the diagnosis of IF/TA was the most important risk factor associated with allograft loss since it could indicate chronic active antibody-mediated rejection. ACEI and MMF were associated with better outcomes, indicating that they might improve graft survival.

  13. Dysregulated autophagy in the RPE is associated with increased susceptibility to oxidative stress and AMD.

    Science.gov (United States)

    Mitter, Sayak K; Song, Chunjuan; Qi, Xiaoping; Mao, Haoyu; Rao, Haripriya; Akin, Debra; Lewin, Alfred; Grant, Maria; Dunn, William; Ding, Jindong; Bowes Rickman, Catherine; Boulton, Michael

    2014-01-01

    Autophagic dysregulation has been suggested in a broad range of neurodegenerative diseases including age-related macular degeneration (AMD). To test whether the autophagy pathway plays a critical role to protect retinal pigmented epithelial (RPE) cells against oxidative stress, we exposed ARPE-19 and primary cultured human RPE cells to both acute (3 and 24 h) and chronic (14 d) oxidative stress and monitored autophagy by western blot, PCR, and autophagosome counts in the presence or absence of autophagy modulators. Acute oxidative stress led to a marked increase in autophagy in the RPE, whereas autophagy was reduced under chronic oxidative stress. Upregulation of autophagy by rapamycin decreased oxidative stress-induced generation of reactive oxygen species (ROS), whereas inhibition of autophagy by 3-methyladenine (3-MA) or by knockdown of ATG7 or BECN1 increased ROS generation, exacerbated oxidative stress-induced reduction of mitochondrial activity, reduced cell viability, and increased lipofuscin. Examination of control human donor specimens and mice demonstrated an age-related increase in autophagosome numbers and expression of autophagy proteins. However, autophagy proteins, autophagosomes, and autophagy flux were significantly reduced in tissue from human donor AMD eyes and 2 animal models of AMD. In conclusion, our data confirm that autophagy plays an important role in protection of the RPE against oxidative stress and lipofuscin accumulation and that impairment of autophagy is likely to exacerbate oxidative stress and contribute to the pathogenesis of AMD.

  14. A ventral glomerular deficit in Parkinson's disease revealed by whole olfactory bulb reconstruction.

    Science.gov (United States)

    Zapiec, Bolek; Dieriks, Birger V; Tan, Sheryl; Faull, Richard L M; Mombaerts, Peter; Curtis, Maurice A

    2017-10-01

    Olfactory dysfunction is common in Parkinson's disease and is an early symptom, but its pathogenesis remains poorly understood. Hindering progress in our mechanistic understanding of olfactory dysfunction in Parkinson's disease is the paucity of literature about the human olfactory bulb, both from normal and Parkinson's disease cases. Qualitatively it is well established that the neat arrangement of the glomerular array seen in the mouse olfactory bulb is missing in humans. But rigorous quantitative approaches to describe and compare the thousands of glomeruli in the human olfactory bulb are not available. Here we report a quantitative approach to describe the glomerular component of the human olfactory bulb, and its application to draw statistical comparisons between olfactory bulbs from normal and Parkinson's disease cases. We subjected horizontal 10 µm sections of olfactory bulbs from six normal and five Parkinson's disease cases to fluorescence immunohistochemistry with antibodies against vesicular glutamate transporter-2 and neural cell adhesion molecule. We scanned the immunostained sections with a fluorescence slide scanner, segmented the glomeruli, and generated 3D reconstructions of whole olfactory bulbs. We document the occurrence of atypical glomerular morphologies and glomerular-like structures deep in the olfactory bulb, both in normal and Parkinson's disease cases. We define a novel and objective parameter: the global glomerular voxel volume, which is the total volume of all voxels that are classified immunohistochemically as glomerular. We find that the global glomerular voxel volume in Parkinson's disease cases is half that of normal cases. The distribution of glomerular voxels along the dorsal-ventral dimension of the olfactory bulb in these series of horizontal sections is significantly altered in Parkinson's disease cases: whereas most glomerular voxels reside within the ventral half of olfactory bulbs from normal cases, glomerular voxels are

  15. Autophagy and Non-Alcoholic Fatty Liver Disease

    Directory of Open Access Journals (Sweden)

    Vanessa J. Lavallard

    2014-01-01

    Full Text Available Autophagy, or cellular self-digestion, is a catabolic process that targets cell constituents including damaged organelles, unfolded proteins, and intracellular pathogens to lysosomes for degradation. Autophagy is crucial for development, differentiation, survival, and homeostasis. Important links between the regulation of autophagy and liver complications associated with obesity, non-alcoholic fatty liver disease (NAFLD, have been reported. The spectrum of these hepatic abnormalities extends from isolated steatosis to non-alcoholic steatohepatitis (NASH, steatofibrosis, which sometimes leads to cirrhosis, and hepatocellular carcinoma. NAFLD is one of the three main causes of cirrhosis and increases the risk of liver-related death and hepatocellular carcinoma. The pathophysiological mechanisms of the progression of a normal liver to steatosis and then more severe disease are complex and still unclear. The regulation of the autophagic flux, a dynamic response, and the knowledge of the role of autophagy in specific cells including hepatocytes, hepatic stellate cells, immune cells, and hepatic cancer cells have been extensively studied these last years. This review will provide insight into the current understanding of autophagy and its role in the evolution of the hepatic complications associated with obesity, from steatosis to hepatocellular carcinoma.

  16. Autophagy and non-alcoholic fatty liver disease.

    Science.gov (United States)

    Lavallard, Vanessa J; Gual, Philippe

    2014-01-01

    Autophagy, or cellular self-digestion, is a catabolic process that targets cell constituents including damaged organelles, unfolded proteins, and intracellular pathogens to lysosomes for degradation. Autophagy is crucial for development, differentiation, survival, and homeostasis. Important links between the regulation of autophagy and liver complications associated with obesity, non-alcoholic fatty liver disease (NAFLD), have been reported. The spectrum of these hepatic abnormalities extends from isolated steatosis to non-alcoholic steatohepatitis (NASH), steatofibrosis, which sometimes leads to cirrhosis, and hepatocellular carcinoma. NAFLD is one of the three main causes of cirrhosis and increases the risk of liver-related death and hepatocellular carcinoma. The pathophysiological mechanisms of the progression of a normal liver to steatosis and then more severe disease are complex and still unclear. The regulation of the autophagic flux, a dynamic response, and the knowledge of the role of autophagy in specific cells including hepatocytes, hepatic stellate cells, immune cells, and hepatic cancer cells have been extensively studied these last years. This review will provide insight into the current understanding of autophagy and its role in the evolution of the hepatic complications associated with obesity, from steatosis to hepatocellular carcinoma.

  17. Enhanced Autophagy in Polycystic Kidneys of AQP11 Null Mice

    Directory of Open Access Journals (Sweden)

    Yasuko Tanaka

    2016-11-01

    Full Text Available Aquaporin-11 (AQP11 is an intracellular water channel expressed at the endoplasmic reticulum (ER of the proximal tubule. Its gene disruption in mice leads to intracellular vacuole formation at one week and the subsequent development of polycystic kidneys by three weeks. As the damaged proximal tubular cells with intracellular vacuoles form cysts later, we postulated that autophagy may play a role in the cyst formation and examined autophagy activity before and after cyst development in AQP11(−/− kidneys. PCR analysis showed the increased expression of the transcript encoding LC3 (Map1lc3b as well as other autophagy-related genes in AQP11(−/− mice. Using green fluorescent protein (GFP-LC3 transgenic mice and AQP11(−/− mice, we found that the number of GFP-LC3–positive puncta was increased in the proximal tubule of AQP11(−/− mice before the cyst formation. Interestingly, they were also observed in the cyst-lining epithelial cell. Further PCR analyses revealed the enhanced expression of apoptosis-related and ER stress–related caspase genes before and after the cyst formation, which may cause the enhanced autophagy. These results suggest the involvement of autophagy in the development and maintenance of kidney cysts in AQP11(−/− mice.

  18. 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

    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. PMID:27077655

  19. Regorafenib delays the proliferation of hepatocellular carcinoma by inducing autophagy.

    Science.gov (United States)

    Han, Rui; Li, Shixin

    2018-04-02

    The aim of the present study was to investigate the effects of regorafenib on hepatocellular carcinoma autophagy, thereby supressing the malignancy of HCC. First, HepG2 and Hep3B cell autophagy was investigated using GFP-LC3 transfection after the treatment of regorafenib. Then, the activation of Akt/mTOR signaling was analyzed using western blot. Our data showed that liver cancer cell autophagy was significantly induced by 20 μM regorafenib using GFP-LC3 transfection. Meanwhile, regorafenib-induced cell death could largely be abolished by 3-MA or CQ treatment, suggesting that regorafenib-induced HepG2 cell death was partially dependent on autophagy. Moreover, the activation of Akt/mTOR signaling was inhibited by regorafenib pre-incubation. MTT assay showed the combination use of regorafenib and CDDP led to a stronger growth inhibitory effect on HepG2 and Hep3B cells. In summary, regorafenib may acts an adjunctive therapy for liver cancer patients via modulating autophagy-dependent cell death even when apoptosis resistance is induced in cancer cells.

  20. The Role of Autophagy in the Pathogenesis of Diabetic Nephropathy

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    Kosuke Yamahara

    2013-01-01

    Full Text Available Diabetic nephropathy is a leading cause of end-stage renal disease worldwide. The multipronged drug approach targeting blood pressure and serum levels of glucose, insulin, and lipids fails to fully prevent the onset and progression of diabetic nephropathy. Therefore, a new therapeutic target to combat diabetic nephropathy is required. Autophagy is a catabolic process that degrades damaged proteins and organelles in mammalian cells and plays a critical role in maintaining cellular homeostasis. The accumulation of proteins and organelles damaged by hyperglycemia and other diabetes-related metabolic changes is highly associated with the development of diabetic nephropathy. Recent studies have suggested that autophagy activity is altered in both podocytes and proximal tubular cells under diabetic conditions. Autophagy activity is regulated by both nutrient state and intracellular stresses. Under diabetic conditions, an altered nutritional state due to nutrient excess may interfere with the autophagic response stimulated by intracellular stresses, leading to exacerbation of organelle dysfunction and diabetic nephropathy. In this review, we discuss new findings showing the relationships between autophagy and diabetic nephropathy and suggest the therapeutic potential of autophagy in diabetic nephropathy.

  1. Autophagy response in the liver of pigeon exposed to avermectin.

    Science.gov (United States)

    Wang, Xian-Song; Liu, Ci; Khoso, Pervez Ahmed; Zheng, Weijia; Li, Ming; Li, Shu

    2017-05-01

    Pesticide residues are an important aspect of environmental pollution. Environmental avermectin residues have produced adverse effects in organisms. Many pesticides exert their toxic effects via the mechanism of autophagy. The purpose of this study was to examine the changes in autophagy levels and in autophagy-related genes, including LC3, Beclin 1, Dynein, ATG5, TORC1, and TORC2, resulting from exposure to subchronic levels of AVM in liver tissue in the king pigeon model. We observed abundant autophagic vacuoles with extensively degraded organelles, autophagosomal vacuoles, secondary lysosomes, and double-membrane structures in the liver. The expression levels of the autophagy-related genes LC3-I, LC3-II, Beclin 1, ATG5, and Dynein were up-regulated; however, TORC1 and TORC2 expression levels were down-regulated. These changes occurred in a concentration-dependent manner after AVM exposure for 30, 60, and 90 days in pigeons. Taken together, these results suggested that AVM increased the autophagic flux and that upregulation of autophagy might be closely related to the hepatotoxicity of AVM in birds.

  2. Ghrelin improves vascular autophagy in rats with vascular calcification.

    Science.gov (United States)

    Xu, Mingming; Liu, Lin; Song, Chenfang; Chen, Wei; Gui, Shuyan

    2017-06-15

    This study aimed to investigate whether ghrelin ameliorated vascular calcification (VC) through improving autophagy. VC model was induced by nicotine plus vitamin D 3 in rats and β-glycerophosphate in vascular smooth muscle cell (VSMC). Calcium deposition was detected by von Kossa staining or alizarin red S staining. ALP activity was also detected. Western blot was used to assess the protein expression. Ghrelin treatment attenuated the elevation of calcium deposition and ALP activity in VC model both in vivo and in vitro. Interesting, the protein levels of autophagy markers, LC3 and beclin1 were significantly upregulated by ghrelin in VC model. An autophagy inhibitor, 3-methyladenine blocks the ameliorative effect of ghrelin on VC. Furthermore, protein expressions of phosphate-AMPK were increased by ghrelin treatment both in calcified aorta and VSMC. The effect of ghrelin on autophagy induction and VC attenuation was prevented by AMPK inhibitor, compound C. Our results suggested that ghrelin improved autophagy through AMPK activation, which was resulted in VC amelioration. These data maybe throw light on prevention and therapy of VC. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Targeting autophagy in obesity: from pathophysiology to management.

    Science.gov (United States)

    Zhang, Yingmei; Sowers, James R; Ren, Jun

    2018-04-23

    Obesity poses a severe threat to human health, including the increased prevalence of hypertension, insulin resistance, diabetes mellitus, cancer, inflammation, sleep apnoea and other chronic diseases. Current therapies focus mainly on suppressing caloric intake, but the efficacy of this approach remains poor. A better understanding of the pathophysiology of obesity will be essential for the management of obesity and its complications. Knowledge gained over the past three decades regarding the aetiological mechanisms underpinning obesity has provided a framework that emphasizes energy imbalance and neurohormonal dysregulation, which are tightly regulated by autophagy. Accordingly, there is an emerging interest in the role of autophagy, a conserved homeostatic process for cellular quality control through the disposal and recycling of cellular components, in the maintenance of cellular homeostasis and organ function by selectively ridding cells of potentially toxic proteins, lipids and organelles. Indeed, defects in autophagy homeostasis are implicated in metabolic disorders, including obesity, insulin resistance, diabetes mellitus and atherosclerosis. In this Review, the alterations in autophagy that occur in response to nutrient stress, and how these changes alter the course of obesogenesis and obesity-related complications, are discussed. The potential of pharmacological modulation of autophagy for the management of obesity is also addressed.

  4. In Situ Immunofluorescent Staining of Autophagy in Muscle Stem Cells

    KAUST Repository

    Castagnetti, Francesco

    2017-06-13

    Increasing evidence points to autophagy as a crucial regulatory process to preserve tissue homeostasis. It is known that autophagy is involved in skeletal muscle development and regeneration, and the autophagic process has been described in several muscular pathologies and agerelated muscle disorders. A recently described block of the autophagic process that correlates with the functional exhaustion of satellite cells during muscle repair supports the notion that active autophagy is coupled with productive muscle regeneration. These data uncover the crucial role of autophagy in satellite cell activation during muscle regeneration in both normal and pathological conditions, such as muscular dystrophies. Here, we provide a protocol to monitor the autophagic process in the adult Muscle Stem Cell (MuSC) compartment during muscle regenerative conditions. This protocol describes the setup methodology to perform in situ immunofluorescence imaging of LC3, an autophagy marker, and MyoD, a myogenic lineage marker, in muscle tissue sections from control and injured mice. The methodology reported allows for monitoring the autophagic process in one specific cell compartment, the MuSC compartment, which plays a central role in orchestrating muscle regeneration.

  5. System-wide Benefits of Intermeal Fasting by Autophagy.

    Science.gov (United States)

    Martinez-Lopez, Nuria; Tarabra, Elena; Toledo, Miriam; Garcia-Macia, Marina; Sahu, Srabani; Coletto, Luisa; Batista-Gonzalez, Ana; Barzilai, Nir; Pessin, Jeffrey E; Schwartz, Gary J; Kersten, Sander; Singh, Rajat

    2017-12-05

    Autophagy failure is associated with metabolic insufficiency. Although caloric restriction (CR) extends healthspan, its adherence in humans is poor. We established an isocaloric twice-a-day (ITAD) feeding model wherein ITAD-fed mice consume the same food amount as ad libitum controls but at two short windows early and late in the diurnal cycle. We hypothesized that ITAD feeding will provide two intervals of intermeal fasting per circadian period and induce autophagy. We show that ITAD feeding modifies circadian autophagy and glucose/lipid metabolism that correlate with feeding-driven changes in circulating insulin. ITAD feeding decreases adiposity and, unlike CR, enhances muscle mass. ITAD feeding drives energy expenditure, lowers lipid levels, suppresses gluconeogenesis, and prevents age/obesity-associated metabolic defects. Using liver-, adipose-, myogenic-, and proopiomelanocortin neuron-specific autophagy-null mice, we mapped the contribution of tissue-specific autophagy to system-wide benefits of ITAD feeding. Our studies suggest that consuming two meals a day without CR could prevent the metabolic syndrome. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. 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. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  7. Organogenesis of the kidney glomerulus: focus on the glomerular basement membrane.

    Science.gov (United States)

    Miner, Jeffrey H

    2011-01-01

    The glomerular basement membrane (GBM) is a crucial component of the kidney's filtration barrier that separates the vasculature from the urinary space. During glomerulogenesis, the GBM is formed from fusion of two distinct basement membranes, one synthesized by the glomerular epithelial cell (podocyte) and the other by the glomerular endothelial cell. The main components of the GBM are laminin-521 (α5β2γ1), collagen α3α4α5(IV), nidogen and the heparan sulfate proteoglycan, agrin. By studying mice lacking specific GBM components, we have shown that during glomerulogenesis, laminin is the only one that is required for GBM integrity and in turn, the GBM is required for completion of glomerulogenesis and glomerular vascularization. In addition, our results from laminin β2-null mice suggest that laminin-521, and thus the GBM, contribute to the establishment and maintenance of the glomerular filtration barrier to plasma albumin. In contrast, mutations that affect GBM collagen IV or agrin do not impair glomerular development or cause immediate leakage of plasma proteins. However, collagen IV mutation, which causes Alport syndrome and ESRD in humans, leads to gradual damage to the GBM that eventually leads to albuminuria and renal failure. These results highlight the importance of the GBM for establishing and maintaining a perfectly functioning, highly selective glomerular filter.

  8. SnRK1 activates autophagy via the TOR signaling pathway in Arabidopsis thaliana.

    Science.gov (United States)

    Soto-Burgos, Junmarie; Bassham, Diane C

    2017-01-01

    Autophagy is a degradation process in which cells break down and recycle their cytoplasmic contents when subjected to environmental stress or during cellular remodeling. The Arabidopsis thaliana SnRK1 complex is a protein kinase that senses changes in energy levels and triggers downstream responses to enable survival. Its mammalian ortholog, AMPK, and yeast ortholog, Snf-1, activate autophagy in response to low energy conditions. We therefore hypothesized that SnRK1 may play a role in the regulation of autophagy in response to nutrient or energy deficiency in Arabidopsis. To test this hypothesis, we determined the effect of overexpression or knockout of the SnRK1 catalytic subunit KIN10 on autophagy activation by abiotic stresses, including nutrient deficiency, salt, osmotic, oxidative, and ER stress. While wild-type plants had low basal autophagy activity in control conditions, KIN10 overexpression lines had increased autophagy under these conditions, indicating activation of autophagy by SnRK1. A kin10 mutant had a basal level of autophagy under control conditions similar to wild-type plants, but activation of autophagy by most abiotic stresses was blocked, indicating that SnRK1 is required for autophagy induction by a wide variety of stress conditions. In mammals, TOR is a negative regulator of autophagy, and AMPK acts to activate autophagy both upstream of TOR, by inhibiting its activity, and in a parallel pathway. Inhibition of Arabidopsis TOR leads to activation of autophagy; inhibition of SnRK1 did not block this activation. Furthermore, an increase in SnRK1 activity was unable to induce autophagy when TOR was also activated. These results demonstrate that SnRK1 acts upstream of TOR in the activation of autophagy in Arabidopsis.

  9. TOR-Dependent and -Independent Pathways Regulate Autophagy in Arabidopsis thaliana.

    Science.gov (United States)

    Pu, Yunting; Luo, Xinjuan; Bassham, Diane C

    2017-01-01

    Autophagy is a critical process for recycling of cytoplasmic materials during environmental stress, senescence and cellular remodeling. It is upregulated under a wide range of abiotic stress conditions and is important for stress tolerance. Autophagy is repressed by the protein kinase target of rapamycin (TOR), which is activated in response to nutrients and in turn upregulates cell growth and translation and inhibits autophagy. Down-regulation of TOR in Arabidopsis thaliana leads to constitutive autophagy and to decreased growth, but the relationship to stress conditions is unclear. Here, we assess the extent to which TOR controls autophagy activation by abiotic stress. Overexpression of TOR inhibited autophagy activation by nutrient starvation, salt and osmotic stress, indicating that activation of autophagy under these conditions requires down-regulation of TOR activity. In contrast, TOR overexpression had no effect on autophagy induced by oxidative stress or ER stress, suggesting that activation of autophagy by these conditions is independent of TOR function. The plant hormone auxin has been shown previously to up-regulate TOR activity. To confirm the existence of two pathways for activation of autophagy, dependent on the stress conditions, auxin was added exogenously to activate TOR, and the effect on autophagy under different conditions was assessed. Consistent with the effect of TOR overexpression, the addition of the auxin NAA inhibited autophagy during nutrient deficiency, salt and osmotic stress, but not during oxidative or ER stress. NAA treatment was unable to block autophagy induced by a TOR inhibitor or by a mutation in the TOR complex component RAPTOR1B , indicating that auxin is upstream of TOR in the regulation of autophagy. We conclude that repression of auxin-regulated TOR activity is required for autophagy activation in response to a subset of abiotic stress conditions.

  10. TOR-Dependent and -Independent Pathways Regulate Autophagy in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yunting Pu

    2017-07-01

    Full Text Available Autophagy is a critical process for recycling of cytoplasmic materials during environmental stress, senescence and cellular remodeling. It is upregulated under a wide range of abiotic stress conditions and is important for stress tolerance. Autophagy is repressed by the protein kinase target of rapamycin (TOR, which is activated in response to nutrients and in turn upregulates cell growth and translation and inhibits autophagy. Down-regulation of TOR in Arabidopsis thaliana leads to constitutive autophagy and to decreased growth, but the relationship to stress conditions is unclear. Here, we assess the extent to which TOR controls autophagy activation by abiotic stress. Overexpression of TOR inhibited autophagy activation by nutrient starvation, salt and osmotic stress, indicating that activation of autophagy under these conditions requires down-regulation of TOR activity. In contrast, TOR overexpression had no effect on autophagy induced by oxidative stress or ER stress, suggesting that activation of autophagy by these conditions is independent of TOR function. The plant hormone auxin has been shown previously to up-regulate TOR activity. To confirm the existence of two pathways for activation of autophagy, dependent on the stress conditions, auxin was added exogenously to activate TOR, and the effect on autophagy under different conditions was assessed. Consistent with the effect of TOR overexpression, the addition of the auxin NAA inhibited autophagy during nutrient deficiency, salt and osmotic stress, but not during oxidative or ER stress. NAA treatment was unable to block autophagy induced by a TOR inhibitor or by a mutation in the TOR complex component RAPTOR1B, indicating that auxin is upstream of TOR in the regulation of autophagy. We conclude that repression of auxin-regulated TOR activity is required for autophagy activation in response to a subset of abiotic stress conditions.

  11. Roles of autophagy in male reproductive development in plants

    Directory of Open Access Journals (Sweden)

    Shigeru eHanamata

    2014-09-01

    Full Text Available Autophagy, a major catabolic pathway in eukaryotic cells, is essential in development, maintenance of cellular homeostasis, immunity and programmed cell death (PCD in multicellular organisms. In plant cells, autophagy plays roles in recycling of proteins and metabolites including lipids, and is involved in many physiological processes such as abiotic and biotic stress responses. However, its roles during reproductive development had remained poorly understood. Quantitative live cell imaging techniques for the autophagic flux and genetic studies in several plant species have recently revealed significant roles of autophagy in developmental processes, regulation of PCD and lipid metabolism. We here review the novel roles of autophagic fluxes in plant cells, and discuss their possible significance in PCD and metabolic regulation, with particular focus on male reproductive development during the pollen maturation.

  12. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. 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

  14. Assessment of glomerular filtration rate and effective renal plasma flow in cystic fibrosis

    International Nuclear Information System (INIS)

    Spino, M.; Chai, R.P.; Isles, A.F.; Balfe, J.W.; Brown, R.G.; Thiessen, J.J.; MacLeod, S.M.

    1985-01-01

    A study was conducted to examine renal function in 10 healthy control subjects and eight patients with cystic fibrosis in stable condition. Sequential bolus injections of /sup 99m/Tc-DTPA and 125 I-OIH were administered to assess glomerular filtration rate and effective renal plasma flow, respectively. Blood was subsequently collected for 3 hours, and urine for 24 hours. Renal clearances of both radioisotope markers were virtually identical in patients and controls. Inasmuch as neither glomerular filtration rate nor effective renal plasma flow was enhanced in patients with cystic fibrosis, increased clearance of drugs in these patients is unlikely to be the result of enhanced glomerular filtration or tubular secretion

  15. Changing the concepts of immune-mediated glomerular diseases through proteomics.

    Science.gov (United States)

    Caster, Dawn J; Hobeika, Liliane; Klein, Jon B; Powell, David W; McLeish, Kenneth R

    2015-12-01

    Standard classification of glomerular diseases is based on histopathologic abnormalities. The recent application of proteomic technologies has resulted in paradigm changes in the understanding and classification of idiopathic membranous nephropathy and membranoproliferative glomerulonephritis. Those examples provide evidence that proteomics will lead to advances in understanding of the molecular basis of other glomerular diseases, such as lupus nephritis. Proof of principle experiments show that proteomics can be applied to patient renal biopsy specimens. This viewpoint summarizes the advances in immune-mediated glomerular diseases that have relied on proteomics, and potential future applications are discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Shock Wave Therapy Promotes Cardiomyocyte Autophagy and Survival during Hypoxia

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    Ling Du

    2017-06-01

    Full Text Available Background: Autophagy plays an important role in cardiovascular disease. Controversy still exists regarding the effect of autophagy on ischemic/hypoxic myocardium. Cardiac shock wave therapy (CSWT is an effective alternative treatment for refractory ischemic heart disease. Whether CSWT can regulate cardiomyocyte autophagy under hypoxic conditions is not clear. We established a myocardial hypoxia model using the H9c2 cell line and performed shock waves (SWs treatment to evaluate the effect of SW on autophagy. Methods: The H9c2 cells were incubated under hypoxic conditions, and SW treatment was then performed at energies of 0.02, 0.05, or 0.10 mJ/mm2. The cell viability and intracellular ATP level were examined. Western blot analysis was used to assess the expression of LC3B, AMPK, mTOR, Beclin-1, Sirt1, and HIF-1α. Autophagic vacuoles were visualized by monodansylcadaverine staining. Results: After the 24-hour hypoxic period, cardiomyocyte viability and ATP levels were decreased and autophagy was significantly increased in H9c2 cells. SW treatment with an energy of 0.05 mJ/mm2 significantly increased the cellular viability, ATP level, LC3B-II/I, and number of autophagic vacuoles. In addition, phosphorylated AMPK and Sirt1 were increased and phosphorylated mTOR and HIF-1α were decreased after SW treatment. Conclusion: SW treatment can potentially promote cardiomyocyte autophagy during hypoxia and protect cardiomyocyte function by regulating the AMPK/mTOR pathway.

  17. Autophagy regulates the stemness of cervical cancer stem cells

    Directory of Open Access Journals (Sweden)

    Yang Y

    2017-06-01

    Full Text Available Yi Yang,1,2 Li Yu,1 Jin Li,1 Ya Hong Yuan,1 Xiao Li Wang,1 Shi Rong Yan,1 Dong Sheng Li,1 Yan Ding1 1Hubei Key Laboratory of Embryonic Stem Cell Research, 2Reproductive Center, Taihe Hospital, Hubei University of Medicine, Shiyan, People’s Republic of China Abstract: Cancer stem cells (CSCs are a rare population of multipotent cells with the capacity to self-renew. It has been reported that there are CSCs in cervical cancer cells. Pluripotency-associated (PA transcription factors such as Oct4, Sox2, Nanog and CD44 have been used to isolate CSCs subpopulations. In this study, we showed that autophagy plays an important role in the biological behavior of cervical cancer cells. The expression of the autophagy protein Beclin 1 and LC3B was higher in tumorspheres established from human cervical cancers cell lines (and CaSki than in the parental adherent cells. It was also observed that the basal and starvation-induced autophagy flux was higher in tumorspheres than in the bulk population. Autophagy could regulate the expression level of PA proteins in cervical CSCs. In addition, CRISPR/Cas 9-mediated Beclin 1 knockout enhanced the malignancy of HeLa cells, leading to accumulation of PA proteins and promoted tumorsphere formation. Our findings suggest that autophagy modulates homeostasis of PA proteins, and Beclin 1 is critical for CSC maintenance and tumor development in nude mice. This demonstrates that a prosurvival autophagic pathway is critical for CSC maintenance. Keywords: cervical cancer, autophagy, cancer stem cell, LC3, Oct4

  18. Tuning flux: autophagy as a target of heart disease therapy

    Science.gov (United States)

    Xie, Min; Morales, Cyndi R.; Lavandero, Sergio; Hill, Joseph A.

    2013-01-01

    Purpose of review Despite maximum medical and mechanical support therapy, heart failure remains a relentlessly progressive disorder with substantial morbidity and mortality. Autophagy, an evolutionarily conserved process of cellular cannibalization, has been implicated in virtually all forms of cardiovascular disease. Indeed, its role is context dependent, antagonizing or promoting disease depending on the circumstance. Here, we review current understanding of the role of autophagy in the pathogenesis of heart failure and explore this pathway as a target of therapeutic intervention. Recent findings In preclinical models of heart disease, cardiomyocyte autophagic flux is activated; indeed, its role in disease pathogenesis is the subject of intense investigation to define mechanism. Similarly, in failing human heart of a variety of etiologies, cardiomyocyte autophagic activity is upregulated, and therapy, such as with mechanical support systems, elicits declines in autophagy activity. However, when suppression of autophagy is complete, rapid and catastrophic cell death occurs, consistent with a model in which basal autophagic flux is required for proteostasis. Thus, a narrow zone of ‘optimal’ autophagy seems to exist. The challenge moving forward is to tune the stress-triggered autophagic response within that ‘sweet spot’ range for therapeutic benefit. Summary Whereas we have known for some years of the participation of lysosomal mechanisms in heart disease, it is only recently that upstream mechanisms (autophagy) are being explored. The challenge for the future is to dissect the underlying circuitry and titrate the response into an optimal, proteostasis-promoting range in hopes of mitigating the ever-expanding epidemic of heart failure. PMID:21415729

  19. Crosstalk between autophagy and inflammatory signalling pathways: balancing defence and homeostasis.

    Science.gov (United States)

    Cadwell, Ken

    2016-11-01

    Autophagy has broad functions in immunity, ranging from cell-autonomous defence to coordination of complex multicellular immune responses. The successful resolution of infection and avoidance of autoimmunity necessitates efficient and timely communication between autophagy and pathways that sense the immune environment. The recent literature indicates that a variety of immune mediators induce or repress autophagy. It is also becoming increasingly clear that immune signalling cascades are subject to regulation by autophagy, and that a return to homeostasis following a robust immune response is critically dependent on this pathway. Importantly, examples of non-canonical forms of autophagy in mediating immunity are pervasive. In this article, the progress in elucidating mechanisms of crosstalk between autophagy and inflammatory signalling cascades is reviewed. Improved mechanistic understanding of the autophagy machinery offers hope for treating infectious and inflammatory diseases.

  20. Autophagy-regulating protease Atg4: structure, function, regulation and inhibition

    Science.gov (United States)

    Maruyama, Tatsuro; Noda, Nobuo N

    2018-01-01

    Autophagy is an intracellular degradation system that contributes to cellular homeostasis through degradation of various targets such as proteins, organelles and microbes. Since autophagy is related to various diseases such as infection, neurodegenerative diseases and cancer, it is attracting attention as a new therapeutic target. Autophagy is mediated by dozens of autophagy-related (Atg) proteins, among which Atg4 is the sole protease that regulates autophagy through the processing and deconjugating of Atg8. As the Atg4 activity is essential and highly specific to autophagy, Atg4 is a prospective target for developing autophagy-specific inhibitors. In this review article, we summarize our current knowledge of the structure, function and regulation of Atg4 including efforts to develop Atg4-specific inhibitors. PMID:28901328

  1. Glomerular filtration rate estimation in renal transplant patients based on serum cystatin-C levels: comparison with other markers of glomerular filtration rate.

    Science.gov (United States)

    Visvardis, G; Griveas, I; Zilidou, R; Papadopoulou, D; Mitsopoulos, E; Kyriklidou, P; Manou, E; Ginikopoulou, E; Meimaridou, D; Pavlitou, A; Sakellariou, G

    2004-01-01

    The assessment of glomerular filtration rate (GFR) is the most commonly used test of renal function. Cystatin-C, a cysteine protease inhibitor, which can be measured by light-scattering immunoassay, possesses many of the attributes required of the ideal GFR marker. Conversely, many endogenous markers that are widely used for the estimation of GFR such as serum creatinine (SCr) are not ideal. The present study was undertaken to evaluate the clinical application of serum cystatin-C (CysC) as a new marker of GFR in renal transplant patients. Eighteen patients (9 men) were enrolled in the study (mean age: 46.35, range: 31-67 years) to measure serum CysC levels and compare them, with SCr, creatinine clearance (CCr), as well as the Cockcroft-Gault equation (CG) or the MDRD as indicator of GFR. Spearman's correlation coefficient was used to determine the relationship between CysC and other markers. There was a significant negative correlation between serum CysC and CCr (r = -0.768). Moreover, the CysC level was negatively correlated with CG (r = -0.854), positively correlated with SCr (r = 0.629), and negatively correlated with MDRD (r = -0.604). These results indicate that measurement of serum cystatin-C was useful and accurate to estimate GFR in renal transplant patients. The recent literature confirms our data although there are concerns about nonrenal influence on this test. Although serum CysC can generally be recommended as a marker for GFR, our study is still in progress seeking to validate the conclusions in a larger number of patients.

  2. Physiology Lab Demonstration: Glomerular Filtration Rate in a Rat.

    Science.gov (United States)

    Hinojosa-Laborde, Carmen; Jespersen, Brian; Shade, Robert

    2015-07-26

    Measurements of glomerular filtration rate (GFR), and the fractional excretion of sodium (Na) and potassium (K) are critical in assessing renal function in health and disease. GFR is measured as the steady state renal clearance of inulin which is filtered at the glomerulus, but not secreted or reabsorbed along the nephron. The fractional excretion of Na and K can be determined from the concentration of Na and K in plasma and urine. The renal clearance of inulin can be demonstrated in an anesthetized animal which has catheters in the femoral artery, femoral vein and bladder. The equipment and supplies used for this procedure are those commonly available in a research core facility, and thus makes this procedure a practical means for measuring renal function. The purpose of this video is to demonstrate the procedures required to perform a lab demonstration in which renal function is assessed before and after a diuretic drug. The presented technique can be utilized to assess renal function in rat models of renal disease.

  3. American Society of Nephrology quiz and questionnaire 2014: glomerular diseases.

    Science.gov (United States)

    Bomback, Andrew S; Perazella, Mark A; Choi, Michael J

    2015-04-07

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the Annual Kidney Week Meeting of the American Society of Nephrology. Once again, the conference hall was overflowing with audience members and eager quiz participants. Topics covered by the expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases representing each of these categories along with single best answer questions were prepared and submitted by the panel of experts. Before the meeting, program directors of United States nephrology training programs and nephrology fellows answered the questions through an internet-based questionnaire. During the live session, members of the audience tested their knowledge and judgment on a series of case-oriented questions that were prepared and discussed by the experts. They compared their answers in real time using audience response devices with the answers of the nephrology fellows and training program directors. The correct and incorrect answers were then discussed after the audience responses, and the results of the questionnaire were displayed. As always, the audience, lecturers, and moderators enjoyed this educational session. This article recapitulates the session and reproduces its educational value for the readers of CJASN. Enjoy the clinical cases and expert discussions. Copyright © 2015 by the American Society of Nephrology.

  4. GLOMERULAR FILTRATION RATE AS INDICATOR OF RENAL FAILURE IN DIABETICS

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    Saša Đurišić

    2007-10-01

    Full Text Available Diabetic nephropathy is a progredient disease which leads to the end stage renal disease and stands for a leading cause of its development in western countries. About one third of patients included in the dialysis program or transplanation program in the USA are diabetics. The aim of the paper was to analyze the degree of renal failure in diabetics by measuring the glomerular filtration rate (GFR and to show the advantages of this method comparing with serum creatinine levels. Total numbers of 23 patients with diabetes mellitus type 1 or type 2 were anlyzed and controlled monthly during 6 months. Average GFR in the examined patients was 53,23±15,48 mL/min/1.73m2. Obtained values for GFR according to CKD Care and ESRD recommendations showed that the great number of diabetics had stage 3 renal failure while stages 1 and 5 were not registered. GFR is an important marker for diagnostics and estimation of renal failure progression in diabetics. Bearing in mind this facts, periodical controls in diabetics must be suplemented by measuring GFR, so as to perform early identification and determination of severity of renal failure. Measuring of lipoprotein levels and determination of glycemic profile must be done according to the National recommendations twice a year. Besides adequate glycoregulation, diabetics need statins therapy and antyhipertensive tratment with ACE inhibitors.

  5. 125I iothalamate an ideal marker for glomerular filtration

    International Nuclear Information System (INIS)

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

    1985-01-01

    The triiodinated angiographic contrast medium, iothalamate (usually labelled 125 I), has been used extensively as a marker for glomerular filtration. The authors have studied the renal handling of 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 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 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

  6. 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.

  7. American Society of Nephrology Quiz and Questionnaire 2015: Glomerular Diseases.

    Science.gov (United States)

    Bomback, Andrew S; Perazella, Mark A; Choi, Michael J

    2016-05-06

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the annual Kidney Week meeting of the American Society of Nephrology. Once again, the conference hall was overflowing with audience members and eager quiz participants. Topics covered by the expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and kidney transplantation. Complex cases representing each of these categories, along with single-best-answer questions, were prepared and submitted by the panel of experts. Before the meeting, training program directors of United States nephrology fellowship programs and nephrology fellows answered the questions through an Internet-based questionnaire. During the live session, members of the audience tested their knowledge and judgment on a series of case-oriented questions prepared and discussed by the experts. They compared their answers in real time using their cell phones with a special app with the answers of the nephrology fellows and training program directors. The correct and incorrect answers were then discussed after the results of the questionnaire were displayed. As always, the audience, lecturers, and moderators enjoyed this educational session. This article recapitulates the session and reproduces its educational value for Clinical Journal of the American Society of Nephrology readers. Enjoy the clinical cases and expert discussions. Copyright © 2016 by the American Society of Nephrology.

  8. Prohibitin 1 modulates mitochondrial stress-related autophagy in human colonic epithelial cells.

    Directory of Open Access Journals (Sweden)

    Arwa S Kathiria

    Full Text Available 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.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.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.Decreased PHB levels coupled with dysfunctional autophagy renders intestinal epithelial cells

  9. The lack of autophagy triggers precocious activation of Notch signaling during Drosophila oogenesis

    Directory of Open Access Journals (Sweden)

    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.

  10. Basement membrane proteoglycans in glomerular morphogenesis: chondroitin sulfate proteoglycan is temporally and spatially restricted during development

    DEFF Research Database (Denmark)

    McCarthy, K J; Bynum, K; St John, P L

    1993-01-01

    basement membrane (GBM) but present in other basement membranes of the nephron, including collecting ducts, tubules, Bowman's capsule, and the glomerular mesangium. In light of this unique pattern of distribution and of the complex histoarchitectural reorganization occurring during nephrogenesis...

  11. Morphological aspects of the rat kidney preserved by cold storage. I. Glomerular morphometric changes.

    Science.gov (United States)

    Neagu, S; Chirculescu, A R; Ranga, V; Popescu, F

    1983-01-01

    The absolute density of glomeruli in the microscopic field was determined in the rat kidney preserved by cold storage for 24, 48, 72 and 96 hrs in two different media: Sacks (hyperosmolar electrolytic solution of intracellular type) and Plasmagel (gelatin solution 4%). Progressive, statistically significant (p less than 0.01) decrease of glomerular density at 24 and 48 hrs was followed by return to initial values at 96 hrs. Decrease of the glomerular density was greater with Plasmagel.

  12. [Effect of collagenase on the permeability of the glomerular basement membrane in the rat kidney].

    Science.gov (United States)

    Laloi, C; Geloso-Meyer, A; Cheignon, M; Schaeverbeke, J

    1981-03-16

    Recently, several authors have emphasized the role of negative sites located in th laminae rarae of the glomerular basement membrane (GBM), in restricting glomerular permeability to anionic macromolecules. In this work, we point out that ultrafiltration properties involve integrity of the GBM. Indeed after intravenous perfusion of bacterian collagenase, anionic ferritin permeates the GBM though negative site distribution (as shown by fixation of colloidal iron) is unaffected.

  13. Haemodynamic influences on kidney oxygenation: clinical implications of integrative physiology

    NARCIS (Netherlands)

    Evans, Roger G.; Ince, Can; Joles, Jaap A.; Smith, David W.; May, Clive N.; O'Connor, Paul M.; Gardiner, Bruce S.

    2013-01-01

    Renal blood flow, local tissue perfusion and blood oxygen content are the major determinants of oxygen delivery to kidney tissue. Arterial pressure and segmental vascular resistance influence kidney oxygen consumption through effects on glomerular filtration rate and sodium reabsorption. Diffusive

  14. Progression of renal injury toward interstitial inflammation and glomerular sclerosis is dependent on abnormal protein filtration.

    Science.gov (United States)

    Zoja, Carlamaria; Abbate, Mauro; Remuzzi, Giuseppe

    2015-05-01

    Chronic proteinuric renal diseases, independent from the type of the initial insult, have in common a loss of selectivity of the glomerular barrier to protein filtration. Glomerular sclerosis is the progressive lesion affecting the glomerular capillary wall, the primary site at which the protein filtration is abnormally enhanced by disease. Dysfunction of podocytes, that serve to maintain the intact barrier, is a central event in lesion development. However, glomerular injury is signalled to tubular and interstitial structures largely in advance of nephron destruction. Glomerular ultrafiltration of excessive amounts of plasma-derived proteins and associated factors incites tubulointerstitial damage and might amplify an inherent susceptibility of the kidney to become dysfunctional in several disease conditions. Thus, noxious substances in the proteinuric ultrafiltrate promote apoptotic responses and multiple changes in the phenotype of tubule cells with generation of inflammatory and fibrogenic mediators. The severity of tubular interstitial damage has long been recognized to be highly correlated to the degree of deterioration of renal failure even better than glomerular lesions. This review focuses on pathways of tubular injury and apoptosis that in turn promote nephron-by-nephron degeneration and interstitial fibrosis during proteinuria contributing to multifaceted processes of kidney scarring and function loss. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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. The Nobel Prize for understanding autophagy, a cellular mechanism ...

    Indian Academy of Sciences (India)

    The Nobel Prize in Physiology or Medicine, 2016, was awarded to Prof Yoshinori Ohsumi from TokyoInstitute of Technology, Yokohoma, Japan, for his work that helped in understanding the molecularmechanisms of autophagy, a process used by most eukaryotic cells to degrade a portion of cytoplasmincluding damaged ...

  17. Functions of autophagy in plant carbon and nitrogen metabolism

    Directory of Open Access Journals (Sweden)

    Chenxia eRen

    2014-06-01

    Full Text Available Carbon and nitrogen are essential components for plant growth. Although models of plant carbon and nitrogen metabolisms have long been established, certain gaps remain unfilled, such as how plants are able to maintain a flexible nocturnal starch turnover capacity over various light cycles, or how nitrogen remobilization is achieved during the reproductive growth stage. Recent advances in plant autophagy have shed light on such questions. Not only does autophagy contribute to starch degradation at night, but it participates in the degradation of chloroplast proteins and even chloroplasts after prolonged carbon starvation, thus help maintain the free amino acid pool and provide substrate for respiration. The induction of autophagy under these conditions may involve transcriptional regulation. Large-scale transcriptome analyses revealed that ATG8e belongs to a core carbon signaling response shared by Arabidopsis accessions, and the transcription of Arabidopsis ATG7 is tightly co-regulated with genes functioning in chlorophyll degradation and leaf senescence. In the reproductive phase, autophagy is essential for bulk degradation of leaf proteins, thus contributes to Nitrogen Use Efficiency (NUE both under normal and low-nitrogen conditions.

  18. Pseudomonas toxin pyocyanin triggers autophagy: Implications for pathoadaptive mutations.

    Science.gov (United States)

    Yang, Zhong-Shan; Ma, Lan-Qing; Zhu, Kun; Yan, Jin-Yuan; Bian, Li; Zhang, Ke-Qin; Zou, Cheng-Gang

    2016-06-02

    Pseudomonas aeruginosa can establish life-long chronic infection in patients with cystic fibrosis by generating genetic loss-of-function mutations, which enhance fitness of the bacterium in the airways. However, the precise role of the pathoadaptive mutations in persistence in chronic airways infection remains largely unknown. Here we demonstrate that pyocyanin, a well-described P. aeruginosa virulence factor that plays an important role in the initial infection, promotes autophagy in bronchial epithelial cells. Disruption of phzM, which is required for pyocyanin biosynthesis, leads to a significant reduction in autophagy in Beas-2B cells and lung tissues. Pyocyanin-induced autophagy is mediated by the EIF2AK4/GCN2-EIF2S1/eIF2α-ATF4 pathway. Interestingly, rats infected with the phzMΔ mutant strain have high mortality rate and numbers of colony-forming units, compared to those infected with wild-type (WT) P. aeruginosa PA14 strain, during chronic P. aeruginosa infection. In addition, the phzMΔ mutant strain induces more extensive alveolar wall thickening than the WT strain in the pulmonary airways of rats. As autophagy plays an essential role in suppressing bacterial burden, our findings provide a detailed understanding of why reduction of pyocyanin production in P. aeruginosa in chronic airways infections has been associated with better host adaptation and worse outcomes in cystic fibrosis.

  19. Chlorogenic acid alleviates autophagy and insulin resistance by ...

    Indian Academy of Sciences (India)

    49

    with hypertension, obesity, dyslipidemia and type 2 diabetes (Lim et al, 2015). A prevalent hypothesis for NAFLD development points out that insulin resistance, as the. “first-hit” to the liver, elicits the onset of second hits, such as oxidative stress, inflammation, apoptosis, and autophagy (Polyzos et al, 2012). Indeed, insulin.

  20. Inhibition of mammalian S6 kinase by resveratrol suppresses autophagy

    Science.gov (United States)

    Armour, Sean M.; Baur, Joseph A.; Hsieh, Sherry N.; Land-Bracha, Abigail; Thomas, Sheila M.; Sinclair, David A.

    2009-01-01

    Resveratrol is a plant-derived polyphenol that promotes health and disease resistance in rodent models, and extends lifespan in lower organisms. A major challenge is to understand the biological processes and molecular pathways by which resveratrol induces these beneficial effects. Autophagy is a critical process by which cells turn over damaged components and maintain bioenergetic requirements. Disruption of the normal balance between pro- and anti-autophagic signals is linked to cancer, liver disease, and neurodegenerative disorders. Here we show that resveratrol attenuates autophagy in response to nutrient limitation or rapamycin in multiple cell lines through a pathway independent of a known target, SIRT1. In a large-scalein vitro kinase screen we identified p70 S6 kinase (S6K1) as a target of resveratrol. Blocking S6K1 activity by expression of a dominant-negative mutant or RNA interference is sufficient to disrupt autophagy to a similar extent as resveratrol. Furthermore, co-administration of resveratrol with S6K1 knockdown does not produce an additive effect. These data indicate that S6K1 is important for the full induction of autophagy in mammals and raise the possibility that some of the beneficial effects of resveratrol are due to modulation of S6K1 activity. PMID:20157535

  1. Lipid Storage and Autophagy in Melanoma Cancer Cells

    Directory of Open Access Journals (Sweden)

    Claudia Giampietri

    2017-06-01

    Full Text Available Cancer stem cells (CSC represent a key cellular subpopulation controlling biological features such as cancer progression in all cancer types. By using melanospheres established from human melanoma patients, we compared less differentiated melanosphere-derived CSC to differentiating melanosphere-derived cells. Increased lipid uptake was found in melanosphere-derived CSC vs. differentiating melanosphere-derived cells, paralleled by strong expression of lipogenic factors Sterol Regulatory Element-Binding Protein-1 (SREBP-1 and Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ. An inverse relation between lipid-storing phenotype and autophagy was also found, since microtubule-associated protein 1A/1B-Light Chain 3 (LC3 lipidation is reduced in melanosphere-derived CSC. To investigate upstream autophagy regulators, Phospho-AMP activated Protein Kinase (P-AMPK and Phospho-mammalian Target of Rapamycin (P-mTOR were analyzed; lower P-AMPK and higher P-mTOR expression in melanosphere-derived CSC were found, thus explaining, at least in part, their lower autophagic activity. In addition, co-localization of LC3-stained autophagosome spots and perilipin-stained lipid droplets was demonstrated mainly in differentiating melanosphere-derived cells, further supporting the role of autophagy in lipid droplets clearance. The present manuscript demonstrates an inverse relationship between lipid-storing phenotype and melanoma stem cells differentiation, providing novel indications involving autophagy in melanoma stem cells biology.

  2. Exocyst and autophagy-related membrane trafficking in plants

    Czech Academy of Sciences Publication Activity Database

    Pečenková, Tamara; Marković, Vedrana; Sabol, P.; Kulich, I.; Žárský, Viktor

    2018-01-01

    Roč. 69, č. 1 (2018), s. 47-57 ISSN 0022-0957 R&D Projects: GA ČR(CZ) GA15-14886S Institutional support: RVO:61389030 Keywords : Autophagy * endomembranes * exocyst * plant defence * secretory transport * ups Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Cell biology Impact factor: 5.830, year: 2016

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

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... This article briefly summarizes seminal discoveries that are shedding new light on the critical and unique roles of autophagy in AD and potential therapeutic ... those of the staff, the journals, various programmes, and Current Science, has changed from 'ias.ernet.in' (or 'academy.ias.ernet.in') to 'ias.ac.in'.

  4. Inhibition of mammalian S6 kinase by resveratrol suppresses autophagy.

    Science.gov (United States)

    Armour, Sean M; Baur, Joseph A; Hsieh, Sherry N; Land-Bracha, Abigail; Thomas, Sheila M; Sinclair, David A

    2009-06-03

    Resveratrol is a plant-derived polyphenol that promotes health and disease resistance in rodent models, and extends lifespan in lower organisms. A major challenge is to understand the biological processes and molecular pathways by which resveratrol induces these beneficial effects. Autophagy is a critical process by which cells turn over damaged components and maintain bioenergetic requirements. Disruption of the normal balance between pro- and anti-autophagic signals is linked to cancer, liver disease, and neurodegenerative disorders. Here we show that resveratrol attenuates autophagy in response to nutrient limitation or rapamycin in multiple cell lines through a pathway independent of a known target, SIRT1. In a large-scalein vitro kinase screen we identified p70 S6 kinase (S6K1) as a target of resveratrol. Blocking S6K1 activity by expression of a dominant-negative mutant or RNA interference is sufficient to disrupt autophagy to a similar extent as resveratrol. Furthermore, co-administration of resveratrol with S6K1 knockdown does not produce an additive effect. These data indicate that S6K1 is important for the full induction of autophagy in mammals and raise the possibility that some of the beneficial effects of resveratrol are due to modulation of S6K1 activity.

  5. Checks and Balances between Autophagy and Inflammasomes during Infection

    Science.gov (United States)

    Seveau, Stephanie; Turner, Joanne; Gavrilin, Mikhail A.; Torrelles, Jordi B.; Hall-Stoodley, Luanne; Yount, Jacob S.; Amer, Amal O.

    2017-01-01

    Autophagy and inflammasome complex assembly are physiological processes that control homeostasis, inflammation, and immunity. Autophagy is a ubiquitous pathway that degrades cytosolic macromolecules or organelles, as well as intracellular pathogens. Inflammasomes are multi-protein complexes that assemble in the cytosol of cells upon detection of pathogen- or danger-associated molecular patterns. A critical outcome of inflammasome assembly is the activation of the serine protease caspase-1, which activates the pro-inflammatory cytokine precursors pro-IL-1β and pro-IL-18. Studies on chronic inflammatory diseases, heart diseases, Alzheimer's disease, and multiple sclerosis revealed that autophagy and inflammasomes intersect and regulate each other. In the context of infectious diseases, however, less is known about the interplay between autophagy and inflammasome assembly, although it is becoming evident that pathogens have evolved multiple strategies to inhibit and/or subvert these pathways and to take advantage of their intricate crosstalk. An improved appreciation of these pathways and their subversion by diverse pathogens is expected to help in the design of anti-infective therapeutic interventions. PMID:29162504

  6. The yeast autophagy protease Atg4 is regulated by thioredoxin.

    Science.gov (United States)

    Pérez-Pérez, María Esther; Zaffagnini, Mirko; Marchand, Christophe H; Crespo, José L; Lemaire, Stéphane D

    2014-01-01

    Autophagy is a membrane-trafficking process whereby double-membrane vesicles called autophagosomes engulf and deliver intracellular material to the vacuole for degradation. Atg4 is a cysteine protease with an essential function in autophagosome formation. Mounting evidence suggests that reactive oxygen species may play a role in the control of autophagy and could regulate Atg4 activity but the precise mechanisms remain unclear. In this study, we showed that reactive oxygen species activate autophagy in the model yeast Saccharomyces cerevisiae and unraveled the molecular mechanism by which redox balance controls Atg4 activity. A combination of biochemical assays, redox titrations, and site-directed mutagenesis revealed that Atg4 is regulated by oxidoreduction of a single disulfide bond between Cys338 and Cys394. This disulfide has a low redox potential and is very efficiently reduced by thioredoxin, suggesting that this oxidoreductase plays an important role in Atg4 regulation. Accordingly, we found that autophagy activation by rapamycin was more pronounced in a thioredoxin mutant compared with wild-type cells. Moreover, in vivo studies indicated that Cys338 and Cys394 are required for the proper regulation of autophagosome biogenesis, since mutation of these cysteines resulted in increased recruitment of Atg8 to the phagophore assembly site. Thus, we propose that the fine-tuning of Atg4 activity depending on the intracellular redox state may regulate autophagosome formation.

  7. Chlorogenic acid alleviates autophagy and insulin resistance by ...

    Indian Academy of Sciences (India)

    49

    diet-fed rats exhibited an increase in body weight, glucose tolerance, liver injury, insulin resistance, as well as autophagy and C-Jun N-terminal kinase (JNK) pathway. Nevertheless, all these effects were alleviated by CG treatment. Moreover, angiotensin treatment in CG group activated the JNK pathway, and promoted.

  8. Retinoid receptor signaling and autophagy in acute promyelocytic leukemia.

    LENUS (Irish Health Repository)

    Orfali, Nina

    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.

  9. System-wide Benefits of Intermeal Fasting by Autophagy

    NARCIS (Netherlands)

    Martinez-Lopez, Nuria; Tarabra, Elena; Toledo, Miriam; Garcia-Macia, Marina; Sahu, Srabani; Coletto, Luisa; Batista-Gonzalez, Ana; Barzilai, Nir; Pessin, Jeffrey E.; Schwartz, Gary J.; Kersten, Sander; Singh, Rajat

    2017-01-01

    Autophagy failure is associated with metabolic insufficiency. Although caloric restriction (CR) extends healthspan, its adherence in humans is poor. We established an isocaloric twice-a-day (ITAD) feeding model wherein ITAD-fed mice consume the same food amount as ad libitum controls but at two

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

    Directory of Open Access Journals (Sweden)

    Beverly A Schaefer

    Full Text Available 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.

  11. Measurement of glomerular filtration rate in the conscious rat.

    Science.gov (United States)

    Pestel, Sabine; Krzykalla, Volker; Weckesser, Gerhard

    2007-01-01

    Glomerular filtration rate (GFR) is an important parameter for studying drug-induced impairments on renal function in rats. The GFR is calculated from the concentration of creatinine and blood urea nitrogen (BUN) in serum and in urine, respectively. Following current protocols serum and urine samples must be taken from the same animal. Thus, in order to determine time-dependent effects it is necessary to use for each time point one separated group of animals. We developed a statistical test which allows analyzing the GFR from two different groups of animals: one used for repeated serum and the other one used for repeated urine analysis. Serum and urine samples were taken from two different sets of rats which were otherwise treated identically, i.e. drug doses, routes of administration (per os or per inhalation) and tap water loading. For each dose group GFR mean, standard deviation and statistical analysis to identify differences between the dose groups were determined. After determination of the optimal time points for measurements, the effect on GFR of the three reference compounds, furosemide, hydrochlorothiazide and formoterol, was calculated. The results showed that the diuretic drugs furosemide and hydrochlorothiazide decreased the GFR and the antidiuretic drug formoterol increased the GFR, as counter regulation on urine loss or urine retention, respectively. A mathematical model and the corresponding algorithm were developed, which can be used to calculate the GFR, and to test for differences between groups from two separated sets of rats, one used for urine, and the other one for serum analysis. This new method has the potential to reduce the number of animals needed and to improve the quality of data generated from various groups of animals in renal function studies.

  12. /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.

  13. Mammalian autophagy is essential for hepatic and renal ketogenesis during starvation.

    Science.gov (United States)

    Takagi, Ayano; Kume, Shinji; Kondo, Motoyuki; Nakazawa, Jun; Chin-Kanasaki, Masami; Araki, Hisazumi; Araki, Shin-ichi; Koya, Daisuke; Haneda, Masakazu; Chano, Tokuhiro; Matsusaka, Taiji; Nagao, Kenji; Adachi, Yusuke; Chan, Lawrence; Maegawa, Hiroshi; Uzu, Takashi

    2016-01-06

    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 gluconeogenesis during starvation. Though skeletal muscle- and kidney-specific autophagy-deficiency did not alter starvation-induced increases in blood ketone levels, liver-specific autophagy-deficiency significantly attenuated this effect. Interestingly, renal as well as hepatic expression of HMG-CoA synthase 2 increased with prolonged starvation. Furthermore, during starvation, mice lacking autophagy both in liver and kidney showed even lower blood ketone levels and physical activity than mice lacking autophagy only in liver. Starvation induced massive lipid droplet formation in extra-adipose tissues including liver and kidney, which was essential for ketogenesis. Moreover, this process was impaired in the autophagy-deficient liver and kidney. These findings demonstrate that hepatic and renal autophagy are essential for starvation-induced lipid droplet formation and subsequent ketogenesis and, ultimately, for maintaining systemic energy homeostasis. Our findings provide novel biological insights into adaptive mechanisms to combat starvation in mammals.

  14. Nobiletin attenuates adverse cardiac remodeling after acute myocardial infarction in rats via restoring autophagy flux.

    Science.gov (United States)

    Wu, Xiaoqian; Zheng, Dechong; Qin, Yuyan; Liu, Zumei; Zhang, Guiping; Zhu, Xiaoyan; Zeng, Lihuan; Liang, Zhenye

    2017-10-14

    Our previous study showed that autophagy flux was impaired with sustained heart ischemia, which exacerbated adverse cardiac remodeling after acute myocardial infarction (AMI). Here we investigated whether Nobiletin, a citrus polymethoxylated flavonoids, could restore the autophagy flux and improve cardiac prognosis after AMI. AMI was induced by ligating left anterior descending (LAD) coronary artery in rats. Nobiletin improved the post-infarct cardiac dysfunction significantly and attenuated adverse cardiac remodeling. Meanwhile, Nobiletin protected H9C2 cells against oxygen glucose deprivation (OGD) in vitro. The impaired autophagy flux due to ischemia was ameliorated after Nobiletin treatment by testing the autophagy substrate, LC3BⅡ and P62 protein level both in vivo and in vitro. GFP-mRFP-LC3 adenovirus transfection also supported that Nobiletin restored the impaired autophagy flux. Specifically, the autophagy flux inhibitor, chloroquine, but not 3 MA, alleviated Nobiletin-mediated protection against OGD. Notably, Nobiletin does not affect the activation of classical upstream autophagy signaling pathways. However, Nobiletin increased the lysosome acidation which also supported that Nobiletin accelerated autophagy flux. Taken together, our findings suggested that Nobiletin restored impaired autophagy flux and protected against acute myocardial infarction, suggesting a potential role of autophagy flux in Nobiletin-mediated myocardial protection. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Trehalose-mediated autophagy impairs the anti-viral function of human primary airway epithelial cells.

    Directory of Open Access Journals (Sweden)

    Qun Wu

    Full Text Available Human rhinovirus (HRV is the most common cause of acute exacerbations of chronic lung diseases including asthma. Impaired anti-viral IFN-λ1 production and increased HRV replication in human asthmatic airway epithelial cells may be one of the underlying mechanisms leading to asthma exacerbations. Increased autophagy has been shown in asthmatic airway epithelium, but the role of autophagy in anti-HRV response remains uncertain. Trehalose, a natural glucose disaccharide, has been recognized as an effective autophagy inducer in mammalian cells. In the current study, we used trehalose to induce autophagy in normal human primary airway epithelial cells in order to determine if autophagy directly regulates the anti-viral response against HRV. We found that trehalose-induced autophagy significantly impaired IFN-λ1 expression and increased HRV-16 load. Inhibition of autophagy via knockdown of autophagy-related gene 5 (ATG5 effectively rescued the impaired IFN-λ1 expression by trehalose and subsequently reduced HRV-16 load. Mechanistically, ATG5 protein interacted with retinoic acid-inducible gene I (RIG-I and IFN-β promoter stimulator 1 (IPS-1, two critical molecules involved in the expression of anti-viral interferons. Our results suggest that induction of autophagy in human primary airway epithelial cells inhibits the anti-viral IFN-λ1 expression and facilitates HRV infection. Intervention of excessive autophagy in chronic lung diseases may provide a novel approach to attenuate viral infections and associated disease exacerbations.

  16. The Role of Autophagy in Nanoparticles-Induced Toxicity and Its Related Cellular and Molecular Mechanisms.

    Science.gov (United States)

    Li, Yubin; Ju, Dianwen

    2018-01-01

    In the past decades, nanoparticles have been widely used in industry and pharmaceutical fields for drug delivery, anti-pathogen, and diagnostic imaging purposes because of their unique physicochemical characteristics such as special ultrastructure, dispersity, and effective cellular uptake properties. But the nanotoxicity has been raised over the extensive applications of nanoparticles. Researchers have elucidated series of mechanisms in nanoparticles-induced toxicity, including apoptosis, necrosis, oxidative stress, and autophagy. Among upon mechanisms, autophagy was recently recognized as an important cell death style in various nanoparticles-induced toxicity, but the role of autophagy and its related cellular and molecular mechanisms during nanoparticles-triggered toxicity were still confusing. In the chapter, we briefly introduced the general process of autophagy, summarized the different roles of autophagy in various nanoparticle-treated different in vitro/in vivo models, and deeply analyzed the physicochemical and biochemical (cellular and molecular) mechanisms of autophagy during nanoparticles-induced toxicity through listing and summarizing representative examples. Physicochemical mechanisms mainly include dispersity, size, charge, and surface chemistry; cellular mechanisms primarily focus on lysosome impairment, mitochondria dysfunction, mitophagy, endoplasmic reticulum stress and endoplasmic reticulum autophagy; while molecular mechanisms were mainly including autophagy related signaling pathways, hypoxia-inducible factor, and oxidative stress. This chapter highlighted the important role of autophagy as a critical mechanism in nanoparticles-induced toxicity, and the physicochemical and biochemical mechanisms of autophagy triggered by nanoparticles might be useful for establishing a guideline for the evaluation of nanotoxicology, designing and developing new biosafety nanoparticles in the future.

  17. VMP1 related autophagy and apoptosis in colorectal cancer cells: VMP1 regulates cell death

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Qinyi [Department of Ultrasonograph, Changshu No. 2 People’s Hospital, Changshu (China); Zhou, Hao; Chen, Yan [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Shen, Chenglong [Department of General Surgery, Changshu No. 2 People’s Hospital, Changshu (China); He, Songbing; Zhao, Hua; Wang, Liang [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Wan, Daiwei, E-mail: 372710369@qq.com [Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou (China); Gu, Wen, E-mail: 505339704@qq.com [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China)

    2014-01-17

    Highlights: •This research confirmed VMP1 as a regulator of autophagy in colorectal cancer cell lines. •We proved the pro-survival role of VMP1-mediated autophagy in colorectal cancer cell lines. •We found the interaction between VMP1 and BECLIN1 also existing in colorectal cancer cell lines. -- Abstract: Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to address this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death.

  18. SIRT5 regulation of ammonia-induced autophagy and mitophagy

    Science.gov (United States)

    Polletta, Lucia; Vernucci, Enza; Carnevale, Ilaria; Arcangeli, Tania; Rotili, Dante; Palmerio, Silvia; Steegborn, Clemens; Nowak, Theresa; Schutkowski, Mike; Pellegrini, Laura; Sansone, Luigi; Villanova, Lidia; Runci, Alessandra; Pucci, Bruna; Morgante, Emanuela; Fini, Massimo; Mai, Antonello; Russo, Matteo A; Tafani, Marco

    2015-01-01

    In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism. PMID:25700560

  19. Assessment of Autophagy in Neurons and Brain Tissue

    Science.gov (United States)

    Benito-Cuesta, Irene; Diez, Héctor; Ordoñez, Lara; Wandosell, Francisco

    2017-01-01

    Autophagy is a complex process that controls the transport of cytoplasmic components into lysosomes for degradation. This highly conserved proteolytic system involves dynamic and complex processes, using similar molecular elements and machinery from yeast to humans. Moreover, autophagic dysfunction may contribute to a broad spectrum of mammalian diseases. Indeed, in adult tissues, where the capacity for regeneration or cell division is low or absent (e.g., in the mammalian brain), the accumulation of proteins/peptides that would otherwise be recycled or destroyed may have pathological implications. Indeed, such changes are hallmarks of pathologies, like Alzheimer’s, Prion or Parkinson’s disease, known as proteinopathies. However, it is still unclear whether such dysfunction is a cause or an effect in these conditions. One advantage when analysing autophagy in the mammalian brain is that almost all the markers described in different cell lineages and systems appear to be present in the brain, and even in neurons. By contrast, the mixture of cell types present in the brain and the differentiation stage of such neurons, when compared with neurons in culture, make translating basic research to the clinic less straightforward. Thus, the purpose of this review is to describe and discuss the methods available to monitor autophagy in neurons and in the mammalian brain, a process that is not yet fully understood, focusing primarily on mammalian macroautophagy. We will describe some general features of neuronal autophagy that point to our focus on neuropathologies in which macroautophagy may be altered. Indeed, we centre this review around the hypothesis that enhanced autophagy may be able to provide therapeutic benefits in some brain pathologies, like Alzheimer’s disease, considering this pathology as one of the most prevalent proteinopathies. PMID:28832529

  20. A pitfall of glomerular sieving: profibrotic and matrix proteins derive from the Bowman's capsule and not the glomerular tuft in rats with renovascular hypertension.

    Science.gov (United States)

    Steinmetz, O M; Panzer, U; Fehr, S; Meyer-Schwesinger, C; Stahl, R A K; Wenzel, U O

    2007-10-01

    The glomeruli in the non-clipped kidney of rats with 2-kidney, 1-clip hypertension are a classical model for studying the mechanisms of glomerular injury. In the present study, we compared the glomerular expression of PAI-1 and collagen I alpha1 mRNA from glomeruli isolated by the classic technique of sieving with the recently developed technique of tissue laser microdissection. For quantification of mRNA from both methods, real-time PCR was used. Real-time PCR revealed a 9.0 +/- 1.3- and a 7.1 +/- 0.2-fold induction of PAI-1 and collagen I alpha 1, respectively, in the glomeruli from hypertensive rats isolated by sieving. However, in situ hybridization and microdissection revealed that expression of both mRNAs was mainly from the Bowman's capsule and not from the glomerular tuft (10.7 +/- 1.3- and 7.2 +/- 0.6-fold higher induction in whole glomeruli compared with tuft alone). This emphasizes that studies focusing on processes in the mesangium, endothelial cells or podocytes should not rely on glomeruli obtained by sieving. Rather, a technique like the laser microdissection or in situ hybridization should be applied which allows the clear separation of different glomerular and periglomerular compartments.

  1. MicroRNA-144-3p inhibits autophagy activation and enhances Bacillus Calmette-Guérin infection by targeting ATG4a in RAW264.7 macrophage cells.

    Science.gov (United States)

    Guo, Le; Zhou, Linlin; Gao, Qian; Zhang, Aijun; Wei, Jun; Hong, Dantong; Chu, Yuankui; Duan, Xiangguo; Zhang, Ying; Xu, Guangxian

    2017-01-01

    MicroRNAs (miRNAs) are small noncoding nucleotides that play major roles in the response of host immune cells. Autophagy plays a key role in activating the antimicrobial host defense against Mycobacterium tuberculosis (M. tuberculosis). Whether miRNAs specifically influence the activation of macrophage autophagy during M. tuberculosis infection is largely unknown. In the present study, we demonstrate that Mycobacterium bovis Bacillus Calmette-Guérin (BCG) infection of macrophages leads to increased expression of miR-144-3p, which targets autophagy-related gene 4a (ATG4a), to inhibit autophagy activation and antimicrobial responses to BCG. Overexpression of miR-144-3p significantly decreased both mRNA and protein levels of ATG4a, inhibited the formation of autophagosomes in RAW264.7 cells and increased intracellular survival of BCG. However, transfection with miR-144-3p inhibitor led to an increase in ATG4a levels, accelerated the autophagic response in macrophages, and decreased BCG survival in macrophages. The experimental results of this study reveal a novel role of miR-144-3p in inhibiting autophagy activation by targeting ATG4a and enhancing BCG infection, and provide potential targets for developing improved treatment.

  2. Genome-wide analysis of autophagy-related genes in banana highlights MaATG8s in cell death and autophagy in immune response to Fusarium wilt.

    Science.gov (United States)

    Wei, Yunxie; Liu, Wen; Hu, Wei; Liu, Guoyin; Wu, Chunjie; Liu, Wei; Zeng, Hongqiu; He, Chaozu; Shi, Haitao

    2017-08-01

    MaATG8s play important roles in hypersensitive-like cell death and immune response, and autophagy is essential for disease resistance against Foc in banana. Autophagy is responsible for the degradation of damaged cytoplasmic constituents in the lysosomes or vacuoles. Although the effects of autophagy have been extensively revealed in model plants, the possible roles of autophagy-related gene in banana remain unknown. In this study, 32 MaATGs were identified in the draft genome, and the profiles of several MaATGs in response to fungal pathogen Fusarium oxysporum f. sp. cubense (Foc) were also revealled. We found that seven MaATG8s were commonly regulated by Foc. Through transient expression in Nicotiana benthamiana leaves, we highlight the novel roles of MaATG8s in conferring hypersensitive-like cell death, and MaATG8s-mediated hypersensitive response-like cell death is dependent on autophagy. Notablly, autophagy inhibitor 3-methyladenine (3-MA) treatment resulted in decreased disease resistance in response to Foc4, and the effect of 3-MA treatment could be rescued by exogenous salicylic acid, jasmonic acid and ethylene, indicating the involvement of autophagy-mediated plant hormones in banana resistance to Fusarium wilt. Taken together, this study may extend our understanding the putative role of MaATG8s in hypersensitive-like cell death and the essential role of autophagy in immune response against Foc in banana.

  3. 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

  4. Comparing different estimated glomerular filtration rate equations in assessing glomerular function in children based on creatinine and cystatin C.

    Science.gov (United States)

    Conkar, Seçil; Mir, Sevgi; Karaslan, Fatma Nur; Hakverdi, Gülden

    2018-02-27

    Glomerular filtration rate (GFR) is the best marker used to assess renal function. Estimated GFR (eGFR) equations have been developed, and the ideal formula is still under discussion. We wanted to find the most practical and reliable GFR in eGFR formulas. We compared serum creatinine (Scr)- and cystatin C (cysC)-based eGFR formulas in the literature. We also aimed to determine the suitability and the reliability of cysC for practical use in determining GFR in children. We have enrolled 238 children in the study. Measurement of 24-hour creatinine clearance was compared with eGFR equations which are based on Scr, cysC, and creatinine plus cysC. Of the patients (n = 238), 117 were males (49.2%), and 121 (50.8%) were females with a median age of 9.0 years. The areas under the ROC curves of Counahan-Barratt and Bedside Schwartz were equal and 0.89 (with a 95% CI 0.80-0.97). The areas under the ROC curves were not significantly different in all cystatin C-based eGFR equations. The highest AUC values for differentiating normal vs abnormal renal functions according to CrCl 24 were for the CKiD-cysC and CKiD-Scr-cysC equations. In our study, compared with creatinine-based ones, the cystatin C-based formulas did not show much superiority in predicting eGFR. Still, we think Bedside Schwartz is a good formula to provide ease of use because, in this equation, the constant k is same for all age groups. However, the most valuable equations in determining chronic kidney disease are the CKiD-cysC and CKiD-Scr-cysC equations. © 2018 Wiley Periodicals, Inc.

  5. BRAF associated autophagy exploitation: BRAF and autophagy inhibitors synergise to efficiently overcome resistance of BRAF mutant colorectal cancer cells.

    Science.gov (United States)

    Goulielmaki, Maria; Koustas, Evangelos; Moysidou, Eirini; Vlassi, Margarita; Sasazuki, Takehiko; Shirasawa, Senji; Zografos, George; Oikonomou, Eftychia; Pintzas, Alexander

    2016-02-23

    Autophagy is the basic catabolic mechanism that involves cell degradation of unnecessary or dysfunctional cellular components. Autophagy has a controversial role in cancer--both in protecting against tumor progression by isolation of damaged organelles, or by potentially contributing to cancer growth. The impact of autophagy in RAS induced transformation still remains to be further analyzed based on the differential effect of RAS isoforms and tumor cell context. In the present study, the effect of KRAS/BRAF/PIK3CA oncogenic pathways on the autophagic cell properties and on main components of the autophagic machinery like p62 (SQSTM1), Beclin-1 (BECN1) and MAP1LC3 (LC3) in colon cancer cells was investigated. This study provides evidence that BRAF oncogene induces the expression of key autophagic markers, like LC3 and BECN1 in colorectal tumor cells. Herein, PI3K/AKT/MTOR inhibitors induce autophagic tumor properties, whereas RAF/MEK/ERK signalling inhibitors reduce expression of autophagic markers. Based on the ineffectiveness of BRAFV600E inhibitors in BRAFV600E bearing colorectal tumors, the BRAF related autophagic properties in colorectal cancer cells are further exploited, by novel combinatorial anti-cancer protocols. Strong evidence is provided here that pre-treatment of autophagy inhibitor 3-MA followed by its combination with BRAFV600E targeting drug PLX4720 can synergistically sensitize resistant colorectal tumors. Notably, colorectal cancer cells are very sensitive to mono-treatments of another autophagy inhibitor, Bafilomycin A1. The findings of this study are expected to provide novel efficient protocols for treatment of otherwise resistant colorectal tumors bearing BRAFV600E, by exploiting the autophagic properties induced by BRAF oncogene.

  6. Dietary fish oil intake: effects on glomerular prostanoid formation, hemodynamics, and proteinuria in nephrotoxic serum nephritis.

    Science.gov (United States)

    Thaiss, F; Schoeppe, W; Germann, P; Stahl, R A

    1990-08-01

    Dietary fish oil intake improves glomerular pathology and proteinuria in murine models of autoimmune disease. We evaluated glomerular prostanoid formation, glomerular hemodynamics, and proteinuria in rats with nephrotoxic serum nephritis (NSN) to test whether this beneficial effect of marine lipids also applies to other animal models of glomerular immune injury. Rats were fed diets (8 weeks) containing either cod liver oil or sunflower oil. NSN was induced with a rabbit anti-rat glomerular basement membrane antiserum. Antibody injection significantly stimulated glomerular thromboxane B2 (TxB2) formation in animals fed cod liver oil and sunflower oil at 2 hours, 24 hours, and 7 days. TxB2 production in glomeruli of sunflower oil rats, however, was five to seven times higher when compared with that in rats fed cod liver oil. The dietary regimen led to a significant decrease of glomerular TxB2 and prostaglandin E2 formation in the animals receiving cod liver oil when compared with those fed sunflower oil. Induction of NSN resulted in a significant fall of inulin clearance (Cin) and paraaminohippurate clearance at 2 hours, 24 hours, and 7 days in both groups. The decrease in Cin at 2 hours was greater in rats fed cod liver oil when compared with animals receiving sunflower oil (p less than 0.02); it was not different, however, at 24 hours and 7 days. Animals with NSN developed proteinuria. There was no difference in protein excretion between rats fed cod liver oil or those fed sunflower oil (days 2 and 7).(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Research advances in the role of autophagy in liver cells and regulation of MAPK pathway

    Directory of Open Access Journals (Sweden)

    JIANG Na

    2016-05-01

    Full Text Available Autophagy is a highly conservative cellular process in eukaryotes that plays an important role in nutrition and energy metabolism in the liver. It can promote the autophagy of hepatocytes and protect the hepatocytes against the adverse external stimulation, but excessive autophagy can cause autophagic cell death of hepatocytes. Hepatic stellate cells (HSC play an important role in the development and progression of liver fibrosis. Autophagy can provide energy for their activation, but may also lead to their death. This article introduces the relationship of autophagy with hepatocytes/HSC and the mitogen-activated protein kinase pathway, and points out that in-depth studies on the relationship between autophagy and pathway regulation during liver fibrosis can provide new targets for developing antifibrotic drugs.

  8. Primary cilium and autophagy: The avengers of cell-size regulation.

    Science.gov (United States)

    Orhon, Idil; Dupont, Nicolas; Codogno, Patrice

    2016-11-01

    The maintenance of cellular homeostasis in response to extracellular stresses by autophagy is vital for the health of various tissues. Extracellular stimuli may include nutrient starvation, endoplasmic reticulum stress, hypoxia, cytotoxic agents, or mechanical stress. The primary cilium (PC) is a microtubule-based sensory organelle that regulates the integration of various extracellular stimuli. The interconnection between macroautophagy/autophagy and the PC is beginning to be illuminated. In this punctum, we discuss our recent study of PC-dependent autophagy in response to fluid flow in kidney epithelial cells. Urinary flow in kidney tubules creates a shear stress that regulates epithelial cell volume. PC-mediated autophagy is necessary for the regulation of cell size. The signal from the PC is transduced by the activation of STK11/LKB1 and by MTOR inhibition. Our results clarify the physiological role of PC-dependent autophagy in the kidney and suggest that autophagy manipulation may provide a route to the treatment of ciliopathies.

  9. 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...... 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...

  10. Mutation in ATG5 reduces autophagy and leads to ataxia with developmental delay.

    Science.gov (United States)

    Kim, Myungjin; Sandford, Erin; Gatica, Damian; Qiu, Yu; Liu, Xu; Zheng, Yumei; Schulman, Brenda A; Xu, Jishu; Semple, Ian; Ro, Seung-Hyun; Kim, Boyoung; Mavioglu, R Nehir; Tolun, Aslıhan; Jipa, Andras; Takats, Szabolcs; Karpati, Manuela; Li, Jun Z; Yapici, Zuhal; Juhasz, Gabor; Lee, Jun Hee; Klionsky, Daniel J; Burmeister, Margit

    2016-01-26

    Autophagy is required for the homeostasis of cellular material and is proposed to be involved in many aspects of health. Defects in the autophagy pathway have been observed in neurodegenerative disorders; however, no genetically-inherited pathogenic mutations in any of the core autophagy-related (ATG) genes have been reported in human patients to date. We identified a homozygous missense mutation, changing a conserved amino acid, in ATG5 in two siblings with congenital ataxia, mental retardation, and developmental delay. The subjects' cells display a decrease in autophagy flux and defects in conjugation of ATG12 to ATG5. The homologous mutation in yeast demonstrates a 30-50% reduction of induced autophagy. Flies in which Atg5 is substituted with the mutant human ATG5 exhibit severe movement disorder, in contrast to flies expressing the wild-type human protein. Our results demonstrate the critical role of autophagy in preventing neurological diseases and maintaining neuronal health.

  11. [Advances in the research of effects of regulation of cell autophagy on wound healing].

    Science.gov (United States)

    Li, M; Liu, D W

    2017-10-20

    As one of the self-protection mechanism, autophagy widely exists in eukaryotic cells. It plays an important role in maintaining cells survival, update, material recycling, and tissue homeostasis. A series of researches discovered that autophagy played dual function in fibrotic diseases. The induction of autophagy can promote the degradation of collagen on one hand, on the other hand, the regulation of autophagy through microRNA, transforming growth factor β, and other factors can promote the occurrence of fibrosis. In wound healing, autophagy may participate in the pathophysiological processes of inflammation, reepithlialization, and wound remodeling. The regulation of cell autophagy may become an effective way and the new target for treatment of wound and pathological scar.

  12. Autophagy downregulation contributes to insulin resistance mediated injury in insulin receptor knockout podocytes in vitro

    Directory of Open Access Journals (Sweden)

    Ying Xu

    2016-04-01

    Full Text Available It is unknown whether autophagy activity is altered in insulin resistant podocytes and whether autophagy could be a therapeutic target for diabetic nephropathy (DN. Here we used shRNA transfection to knockdown the insulin receptor (IR gene in cultured human immortalized podocytes as an in vitro insulin resistant model. Autophagy related proteins LC3, Beclin, and p62 as well as nephrin, a podocyte injury marker, were assessed using western blot and immunofluorescence staining. Our results show that autophagy is suppressed when podocytes lose insulin sensitivity and that treatment of rapamycin, an mTOR specific inhibitor, could attenuate insulin resistance induced podocytes injury via autophagy activation. The present study deepens our understanding of the role of autophagy in the pathogenesis of DN.

  13. Autophagy, programmed cell death and reactive oxygen species in sexual reproduction in plants.

    Science.gov (United States)

    Kurusu, Takamitsu; Kuchitsu, Kazuyuki

    2017-05-01

    Autophagy is one of the major cellular processes of recycling of proteins, metabolites and intracellular organelles, and plays crucial roles in the regulation of innate immunity, stress responses and programmed cell death (PCD) in many eukaryotes. It is also essential in development and sexual reproduction in many animals. In plants, although autophagy-deficient mutants of Arabidopsis thaliana show phenotypes in abiotic and biotic stress responses, their life cycle seems normal and thus little had been known until recently about the roles of autophagy in development and reproduction. Rice mutants defective in autophagy show sporophytic male sterility and immature pollens, indicating crucial roles of autophagy during pollen maturation. Enzymatic production of reactive oxygen species (ROS) by respiratory burst oxidase homologues (Rbohs) play multiple roles in regulating anther development, pollen tube elongation and fertilization. Significance of autophagy and ROS in the regulation of PCD of transient cells during plant sexual reproduction is discussed in comparison with animals.

  14. Renal endoplasmic reticulum stress is coupled to impaired autophagy in a mouse model of GSD Ia.

    Science.gov (United States)

    Farah, Benjamin L; Landau, Dustin J; Wu, Yajun; Sinha, Rohit A; Loh, Alwin; Bay, Boon-Huat; Koeberl, Dwight D; Yen, Paul M

    2017-11-01

    GSD Ia (von Gierke Disease, Glycogen Storage Disease Type Ia) is a devastating genetic disorder with long-term sequelae, such as non-alcoholic fatty liver disease and renal failure. Down-regulated autophagy is involved in the development of hepatic metabolic dysfunction in GSD Ia; however, the role of autophagy in the renal pathology is unknown. Here we show that autophagy is impaired and endoplasmic reticulum (ER) stress is increased in the kidneys of a mouse model of GSD Ia. Induction of autophagy by rapamycin also reduces this ER stress. Taken together, these results show an additional role for autophagy down-regulation in the pathogenesis of GSD Ia, and provide further justification for the use of autophagy modulators in GSD Ia. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Autophagy sustains the replication of porcine reproductive and respiratory virus in host cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qinghao; Qin, Yixian; Zhou, Lei; Kou, Qiuwen; Guo, Xin; Ge, Xinna [Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agribiotechnology, China Agricultural University, Beijing (China); Yang, Hanchun, E-mail: yanghanchun1@cau.edu.cn [Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agribiotechnology, China Agricultural University, Beijing (China); Hu, Hongbo, E-mail: hongbo@cau.edu.cn [College of Food Science and Nutritional Engineering, China Agricultural University, Beijing (China)

    2012-08-01

    In this study, we confirmed the autophagy induced by porcine reproductive and respiratory syndrome virus (PRRSV) in permissive cells and investigated the role of autophagy in the replication of PRRSV. We first demonstrated that PRRSV infection significantly results in the increased double-membrane vesicles, the accumulation of LC3 fluorescence puncta, and the raised ratio of LC3-II/{beta}-actin, in MARC-145 cells. Then we discovered that induction of autophagy by rapamycin significantly enhances the viral titers of PRRSV, while inhibition of autophagy by 3-MA and silencing of LC3 gene by siRNA reduces the yield of PRRSV. The results showed functional autolysosomes can be formed after PRRSV infection and the autophagosome-lysosome-fusion inhibitor decreases the virus titers. We also examined the induction of autophagy by PRRSV infection in pulmonary alveolar macrophages. These findings indicate that autophagy induced by PRRSV infection plays a role in sustaining the replication of PRRSV in host cells.

  16. Degradation of misfolded proteins by autophagy: is it a strategy for Huntington's disease treatment?

    Science.gov (United States)

    Lin, Fang; Qin, Zheng-Hong

    2013-01-01

    Autophagy is a degradation pathway for long-lived cytoplasmic proteins, protein complexes, or damaged organelles. The accumulation and aggregation of misfolded proteins are hallmarks of several neurodegenerative diseases. Many researchers have reported that autophagy degrades disease-causing misfolded and aggregated proteins, including mutant huntingtin (Htt) in Huntington's disease, mutant synuclein in familial Parkingson's disease, mutant Cu, Zn-Superoxide dismutase (SOD1) in familial amyotrophic lateral sclerosis. In this review, we will bring up new evidence to elucidate the involvement of autophagy in degradation of mutant Htt, discuss the mechanisms regulating the degradation of mutant Htt by autophagy and the therapeutic effects of drugs that enhance autophagy to improve clearance of mutant Htt. We propose that enhancement of autophagy by drugs may be a strategy to treat or retard progression of Huntington's disease.

  17. Validation of estimated glomerular filtration rate equations for Japanese children.

    Science.gov (United States)

    Gotoh, Yoshimitsu; Uemura, Osamu; Ishikura, Kenji; Sakai, Tomoyuki; Hamasaki, Yuko; Araki, Yoshinori; Hamda, Riku; Honda, Masataka

    2018-01-25

    The gold standard for evaluation of kidney function is renal inulin clearance (Cin). However, the methodology for Cin is complicated and difficult, especially for younger children and/or patients with bladder dysfunction. Therefore, we developed a simple and easier method for obtaining the estimated glomerular filtration rate (eGFR) using equations and values for several biomarkers, i.e., serum creatinine (Cr), serum cystatin C (cystC), serum beta-2 microglobulin (β 2 MG), and creatinine clearance (Ccr). The purpose of the present study was to validate these equations with a new data set. To validate each equation, we used data of 140 patients with CKD with clinical need for Cin, using the measured GFR (mGFR). We compared the results for each eGFR equation with the mGFR using mean error (ME), root mean square error (RMSE), P 30 , and Bland-Altman analysis. The ME of Cr, cystC, β 2 MG, and Ccr based on eGFR was 15.8 ± 13.0, 17.2 ± 16.5, 15.4 ± 14.3, and 10.6 ± 13.0 ml/min/1.73 m 2 , respectively. The RMSE was 29.5, 23.8, 20.9, and 16.7, respectively. The P 30 was 79.4, 71.1, 69.5, and 92.9%, respectively. The Bland-Altman bias analysis showed values of 4.0 ± 18.6, 5.3 ± 16.8, 12.7 ± 17.0, and 2.5 ± 17.2 ml/min/1.73 m 2 , respectively, for these parameters. The bias of each eGFR equation was not large. Therefore, each eGFR equation could be used.

  18. Lutein Induces Autophagy via Beclin-1 Upregulation in IEC-6 Rat Intestinal Epithelial Cells.

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    Chang, Chi-Jen; Lin, Ji-Fan; Hsiao, Chien-Yu; Chang, Hsun-Hao; Li, Hsin-Ju; Chang, Hsun-Hsien; Lee, Gon-Ann; Hung, Chi-Feng

    2017-01-01

    Lutein is a carotenoid with anti-oxidant properties. Autophagy, an evolutionarily conserved catabolic cellular pathway for coping with stress conditions, is responsive to reactive oxygen species (ROS) and degrades damaged organelles. We previously demonstrated that lutein can induce anti-oxidant enzymes to relieve methotrexate-induced ROS stress. We therefore hypothesized that lutein, which activates ROS-scavenging enzymes, can also induce autophagy for cell survival. In this study, we demonstrated that lutein treatment attenuated the reduction in cell viability caused by H 2 O 2 . Lutein dose-dependently induced the processing of microtubule-associated protein light chain 3 (LC3)-II, an autophagy marker protein, and accumulation of LC3-positive puncta in rat intestinal IEC-6 cells. Furthermore, (a) direct observation of autophagosome formation through transmission electron microscopy, (b) upregulation of autophagy-related genes including ATG4A, ATG5, ATG7, ATG12, and beclin-1 (BENC1), and (c) increased BECN1/Bcl-2 ratio confirmed the induction of autophagy by lutein. The results revealed that bafilomycin-A1-induced inhibition of autophagy reduced cell viability and increased apoptosis in lutein-treated cells, indicating a protective role of lutein-induced autophagy. Lutein treatment also activated adenosine monophosphate-activated protein kinase (AMPK), c-Jun N-terminal kinase (JNK), and p-38, but had no effects on the induction of extracellular signal-related kinase or inhibition of mTOR; however, the inhibition of activated AMPK, JNK, or p-38 did not attenuate lutein-induced autophagy. Finally, increased BECN1 expression levels were detected in lutein-treated cells, and BECN1 knockdown abolished autophagy induction. These results suggest that lutein-induced autophagy was mediated by the upregulation of BECN1 in IEC-6 cells. We are the first to demonstrate that lutein induces autophagy. Elevated autophagy in lutein-treated IEC-6 cells may have a protective role

  19. Recycling to discover something new: the role of autophagy in kidney disease.

    Science.gov (United States)

    Leventhal, Jeremy S; Wyatt, Christina M; Ross, Michael J

    2017-01-01

    This year, the Nobel Prize in Physiology or Medicine was awarded to Yoshinori Ohsumi for his groundbreaking work in dissecting the mechanisms of autophagy, a cellular process resulting in the organized degradation of cytoplasmic components. Ohsumi's work paved the way for subsequent studies that demonstrated critical roles for autophagy in modulating both acute and chronic kidney injury. This work may lead to future therapeutic approaches that target the autophagy system to prevent or treat kidney diseases. Published by Elsevier Inc.

  20. Impact of cellular autophagy on viruses: Insights from hepatitis B virus and human retroviruses.

    Science.gov (United States)

    Tang, Sai-Wen; Ducroux, Aurelie; Jeang, Kuan-Teh; Neuveut, Christine

    2012-10-30

    Autophagy is a protein degradative process important for normal cellular metabolism. It is apparently used also by cells to eliminate invading pathogens. Interestingly, many pathogens have learned to subvert the cell's autophagic process. Here, we review the interactions between viruses and cells in regards to cellular autophagy. Using findings from hepatitis B virus and human retroviruses, HIV-1 and HTLV-1, we discuss mechanisms used by viruses to usurp cellular autophagy in ways that benefit viral replication.

  1. Effects of aerobic training on markers of autophagy in the elderly

    OpenAIRE

    Mej?as-Pe?a, Yubisay; Rodriguez-Miguelez, Paula; Fernandez-Gonzalo, Rodrigo; Mart?nez-Fl?rez, Susana; Almar, Mar; de Paz, Jos? A.; Cuevas, Mar?a J.; Gonz?lez-Gallego, Javier

    2016-01-01

    Autophagy is a molecular process essential for the maintenance of cellular homeostasis, which appears to (i) decline with age and (ii) respond to physical exercise. In addition, recent evidence suggests a crosstalk between autophagy and toll-like receptor (TLR)-associated inflammatory responses. This study assessed the effects of aerobic exercise training on autophagy and TLR signaling in older subjects. Twenty-nine healthy women and men (age, 69.7???1.0?year) were randomized to a training (T...

  2. Kaempferol induces hepatocellular carcinoma cell death via endoplasmic reticulum stress-CHOP-autophagy signaling pathway

    OpenAIRE

    Guo, Haiqing; Lin, Wei; Zhang, Xiangying; Zhang, Xiaohui; Hu, Zhongjie; Li, Liying; Duan, Zhongping; Zhang, Jing; Ren, Feng

    2017-01-01

    Kaempferol is a flavonoid compound that has gained widespread attention due to its antitumor functions. However, the underlying mechanisms are still not clear. The present study investigated the effect of kaempferol on hepatocellular carcinoma and its underlying mechanisms. Kaempferol induced autophagy in a concentration- and time-dependent manner in HepG2 or Huh7 cells, which was evidenced by the significant increase of autophagy-related genes. Inhibition of autophagy pathway, through 3-meth...

  3. Impaired Autophagy in the Lipid-Storage Disorder Niemann-Pick Type C1 Disease

    OpenAIRE

    Sarkar, Sovan; Carroll, Bernadette; Buganim, Yosef; Maetzel, Dorothea; Ng, Alex H.M.; Cassady, John P.; Cohen, Malkiel A.; Chakraborty, Souvik; Wang, Haoyi; Spooner, Eric; Ploegh, Hidde; Gsponer, Joerg; Korolchuk, Viktor I.; Jaenisch, Rudolf

    2013-01-01

    Autophagy dysfunction has been implicated in misfolded protein accumulation and cellular toxicity in several diseases. Whether alterations in autophagy also contribute to the pathology of lipid-storage disorders is not clear. Here, we show defective autophagy in Niemann-Pick type C1 (NPC1) disease associated with cholesterol accumulation, where the maturation of autophagosomes is impaired because of defective amphisome formation caused by failure in SNARE machinery, whereas the lysosomal prot...

  4. Intermedin suppresses pressure overload cardiac hypertrophy through activation of autophagy.

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    Chen, Huali; Wang, Xue; Tong, Mingming; Wu, Dan; Wu, Sisi; Chen, Jiaxiang; Wang, Xiaoxiao; Wang, Xulei; Kang, Yu; Tang, Hong; Tang, Chaoshu; Jiang, Wei

    2013-01-01

    Left ventricular hypertrophy is a maladaptive response to pressure overload and an important risk factor for heart failure. Intermedin (IMD), a multi-functional peptide, plays important roles in cardiovascular protection. In this study, we revealed an autophagy-dependent mechanism involved in IMD's protection against cardiac remodeling and cardiomyocyte death in heart hypertrophy. We observed that transverse aortic contraction (TAC) induction, Ang II or ISO exposure induced remarkable increase in the expression of endogenous IMD and its receptor components, CRLR, RAMP1 and RAMP3, in mouse hearts and H9c2 cell cultures, respectively. Furthermore, the heart size, heart weight/body weight ratios, cardiomyocyte size and apoptosis, interstitial collagen, hypertrophic markers including ANP and BNP expression were also significantly increased, which were effectively suppressed by IMD supplementation. In addition, IMD induced capillary angiogenesis and improved functions in hypertrophic hearts. We further observed that IMD induced strong autophagy in hypertrophic hearts and cultured cells, which was paralleling with the decrease in cardiomyocyte size and apoptosis. Furthermore, an autophagy inhibitor, 3-MA, was used to block the IMD-augmented autophagy level, and then the protection of IMD on cardiomyocyte hypertrophy and apoptosis was almost abrogated. We also observed that IMD supplementation stirred intracellular cAMP production, and augmented the ERK1/2 phosphorylation induced by Ang II/ISO exposure in H9c2 cells. In addition, we inhibited PI3K, PKA and MAPK/ERK1/2 signaling pathways by using wortamannin, H89 and PD98059, respectively, in H9c2 cells co-incubating with both IMD and Ang II or ISO, and observed that these inhibitors effectively reduced IMD-augmented autophagy level, but only H89 and PD98059 pre-incubation abrogated the anti-apoptotic action of IMD. These results indicate that the endogenous IMD and its receptor complexes are induced in hypertrophic

  5. Intermedin suppresses pressure overload cardiac hypertrophy through activation of autophagy.

    Directory of Open Access Journals (Sweden)

    Huali Chen

    Full Text Available Left ventricular hypertrophy is a maladaptive response to pressure overload and an important risk factor for heart failure. Intermedin (IMD, a multi-functional peptide, plays important roles in cardiovascular protection. In this study, we revealed an autophagy-dependent mechanism involved in IMD's protection against cardiac remodeling and cardiomyocyte death in heart hypertrophy. We observed that transverse aortic contraction (TAC induction, Ang II or ISO exposure induced remarkable increase in the expression of endogenous IMD and its receptor components, CRLR, RAMP1 and RAMP3, in mouse hearts and H9c2 cell cultures, respectively. Furthermore, the heart size, heart weight/body weight ratios, cardiomyocyte size and apoptosis, interstitial collagen, hypertrophic markers including ANP and BNP expression were also significantly increased, which were effectively suppressed by IMD supplementation. In addition, IMD induced capillary angiogenesis and improved functions in hypertrophic hearts. We further observed that IMD induced strong autophagy in hypertrophic hearts and cultured cells, which was paralleling with the decrease in cardiomyocyte size and apoptosis. Furthermore, an autophagy inhibitor, 3-MA, was used to block the IMD-augmented autophagy level, and then the protection of IMD on cardiomyocyte hypertrophy and apoptosis was almost abrogated. We also observed that IMD supplementation stirred intracellular cAMP production, and augmented the ERK1/2 phosphorylation induced by Ang II/ISO exposure in H9c2 cells. In addition, we inhibited PI3K, PKA and MAPK/ERK1/2 signaling pathways by using wortamannin, H89 and PD98059, respectively, in H9c2 cells co-incubating with both IMD and Ang II or ISO, and observed that these inhibitors effectively reduced IMD-augmented autophagy level, but only H89 and PD98059 pre-incubation abrogated the anti-apoptotic action of IMD. These results indicate that the endogenous IMD and its receptor complexes are induced in

  6. Autophagy Mediates Interleukin-1β Secretion in Human Neutrophils

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    Leonardo Iula

    2018-02-01

    Full Text Available Interleukin-1β (IL-1β, a major pro-inflammatory cytokine, is a leaderless cytosolic protein whose secretion does not follow the classical endoplasmic reticulum-to-Golgi pathway, and for which a canonical mechanism of secretion remains to be established. Neutrophils are essential players against bacterial and fungi infections. These cells are rapidly and massively recruited from the circulation into infected tissues and, beyond of displaying an impressive arsenal of toxic weapons effective to kill pathogens, are also an important source of IL-1β in infectious conditions. Here, we analyzed if an unconventional secretory autophagy mechanism is involved in the exportation of IL-1β by these cells. Our findings indicated that inhibition of autophagy with 3-methyladenine and Wortmannin markedly reduced IL-1β secretion induced by LPS + ATP, as did the disruption of the autophagic flux with Bafilomycin A1 and E64d. These compounds did not noticeable affect neutrophil viability ruling out that the effects on IL-1β secretion were due to cell death. Furthermore, VPS34IN-1, a specific autophagy inhibitor, was still able to reduce IL-1β secretion when added after it was synthesized. Moreover, siRNA-mediated knockdown of ATG5 markedly reduced IL-1β secretion in neutrophil-differentiated PLB985 cells. Upon LPS + ATP stimulation, IL-1β was incorporated to an autophagic compartment, as was revealed by its colocalization with LC3B by confocal microscopy. Overlapping of IL-1β-LC3B in a vesicular compartment peaked before IL-1β increased in culture supernatants. On the other hand, stimulation of autophagy by cell starvation augmented the colocalization of IL-1β and LC3B and then promoted neutrophil IL-1β secretion. In addition, specific ELISAs indicated that although both IL-1β and pro-IL-1β are released to culture supernatants upon neutrophil stimulation, autophagy only promotes IL-1β secretion. Furthermore, the serine proteases inhibitor

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

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    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.

  8. Estimated glomerular filtration rate function in patients with and without metabolic syndrome

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    María E Lizardo

    2016-06-01

    Full Text Available Introduction: Metabolic syndrome (MS is an independent risk factor, which affects the development of chronic kidney disease, so the glomerular filtration rate (GFR as an indicator of glomerular function in patients with and without MS who attended the outpatient clinic “los Grillitos, sector Caña de Azucar”. Materials and Methods: A comparative, correlational, cross-sectional study was conducted in a non-probability sample of convenience consisting of 60 patients with MS diagnosed according to the criteria Panel ATP III, and 60 apparently healthy individuals, whom the GFR was determined by the Cockcroft-Gault as well as clinical and biochemical parameters for the diagnosis of MS. Results: Out of the total patients evaluated, 37 (30.7% showed alterations that put them in grades G2 and G3 system risk stratification of CKD, of these 18 and 19 corresponded to patients with and without MS respectively. Glomerular Hyperfiltration (> 120 mil / min it was found in both groups 28 (46.7% and 24 (40% cases of patients with and without MS respectively. The glomerular function was strongly correlated with abdominal obesity and high levels of stress arterial. As for the number of criteria and its relationship to the level of kidney damage present, not a firm to increase the latter with respect to the first (p=0.385 trend was observed. Conclusion: The change in the glomerular function is not directly related to the MS but with its components, specifically abdominal obesity and hypertension.

  9. Renal glomerular lesions in unselected patients with cirrhosis undergoing orthotopic liver transplantation.

    Science.gov (United States)

    Axelsen, R A; Crawford, D H; Endre, Z H; Lynch, S V; Balderson, G A; Strong, R W; Fleming, S J

    1995-07-01

    Renal biopsies were obtained from 23 patients at the time of orthotopic liver transplantation. Twelve biopsies showed minor glomerular abnormalities, 2 exhibited IgA nephropathy and one showed mesangiocapillary glomerulonephritis type I. The remaining 8 patients had glomerular lesions diagnosed as hepatic glomerulosclerosis (HGS). Immunofluorescence, available in 6 of the 8 biopsies with HGS, revealed granular deposits of immunoglobulins and complement in glomerular capillary walls and/or the mesangium. IgA was seen in 5 biopsies with HGS, but the staining for this protein was no more intense than that for the other immunoglobulins in 4 of these. Electron microscopy in HGS revealed partial mesangial interposition, hypertophy of mesangial and endothelial cells, granular material in a widened subendothelial space, slender projections of endothelial cytoplasm extending into the subendothelial space, and clusters of vesicles in the mesangium and glomerular capillary walls. These ultrastructural abnormalities have not hitherto been reported as a group of associated pathological changes. The renal biopsies were obtained from patients with advanced hepatic disease not selected because of urinary abnormalities or renal dysfunction. The frequency of lesions in this group of patients therefore probably reflects the true incidence of glomerular lesions in cirrhosis and related conditions. Progressive decline in renal function was not observed in any patient during follow up which ranged from 11 days to 55 mths.

  10. Childhood primary glomerular diseases in the western region of Saudi Arabia

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    Jalalah Sawsan

    2009-01-01

    Full Text Available We report our institute experience on primary glomerular disease in children in the western region of Saudi Arabia over the last 18 years (1988 to 2006. A total of 169 cases were identified as primary glomerular diseases in children and adolescent with age range from first year of life till 18 years. Minimal change disease and focal segmental glomerulosclerosis were the com-monly encountered primary glomerular diseases (20.1%and 19.5% respectively, mesangioprolifera-tive glomerulonephritis IgM nephropathy (14.8%, IgA nephropathy (10.7%, postinfectious glome-rulonephritis (9.5%, membranous glomerulonephritis (7.1%, membranoproliferative glomerulone-phritis (5.9% and mesangioproliferative glomerulonephritis with negative immunofluorescence (5.9%. The less frequently encountered primary glomerular diseases were congenital nephritic syn-drome Finnish type (2.4%, Alport syndrome (2.4%, dense deposit disease (1.2%, and mesangio-proliferative glomerulonephritis with IgG positive (0.6%. We concluded that minimal change di-sease and focal segmental glomerulosclerosis are the most common primary glomerular disorder en-countered in children in our series and with similar age distribution.

  11. 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.

  12. The Rho-GTPase binding protein IQGAP2 is required for the glomerular filtration barrier.

    Science.gov (United States)

    Sugano, Yuya; Lindenmeyer, Maja T; Auberger, Ines; Ziegler, Urs; Segerer, Stephan; Cohen, Clemens D; Neuhauss, Stephan C F; Loffing, Johannes

    2015-11-01

    Podocyte dysfunction impairs the size selectivity of the glomerular filter, leading to proteinuria, hypoalbuminuria, and edema, clinically defined as nephrotic syndrome. Hereditary forms of nephrotic syndrome are linked to mutations in podocyte-specific genes. To identify genes contributing to podocyte dysfunction in acquired nephrotic syndrome, we studied human glomerular gene expression data sets for glomerular-enriched gene transcripts differentially regulated between pretransplant biopsy samples and biopsies from patients with nephrotic syndrome. Candidate genes were screened by in situ hybridization for expression in the zebrafish pronephros, an easy-to-use in vivo assay system to assess podocyte function. One glomerulus-enriched product was the Rho-GTPase binding protein, IQGAP2. Immunohistochemistry found a strong presence of IQGAP2 in normal human and zebrafish podocytes. In zebrafish larvae, morpholino-based knockdown of iqgap2 caused a mild foot process effacement of zebrafish podocytes and a cystic dilation of the urinary space of Bowman's capsule upon onset of urinary filtration. Moreover, the glomerulus of zebrafish morphants showed a glomerular permeability for injected high-molecular-weight dextrans, indicating an impaired size selectivity of the glomerular filter. Thus, IQGAP2 is a Rho-GTPase binding protein, highly abundant in human and zebrafish podocytes, which controls normal podocyte structure and function as evidenced in the zebrafish pronephros.

  13. TNF-mediated damage to glomerular endothelium is an important determinant of acute kidney injury in sepsis.

    Science.gov (United States)

    Xu, Chang; Chang, Anthony; Hack, Bradley K; Eadon, Michael T; Alper, Seth L; Cunningham, Patrick N

    2014-01-01

    Severe sepsis is often accompanied by acute kidney injury (AKI) and albuminuria. Here we studied whether the AKI and albuminuria associated with lipopolysaccharide (LPS) treatment in mice reflects impairment of the glomerular endothelium with its associated endothelial surface layer. LPS treatment decreased the abundance of endothelial surface layer heparan sulfate proteoglycans and sialic acid, and led to albuminuria likely reflecting altered glomerular filtration permselectivity. LPS treatment decreased the glomerular filtration rate (GFR), while also causing significant ultrastructural alterations in the glomerular endothelium. The density of glomerular endothelial cell fenestrae was 5-fold lower, whereas the average fenestrae diameter was 3-fold higher in LPS-treated than in control mice. The effects of LPS on the glomerular endothelial surface layer, endothelial cell fenestrae, GFR, and albuminuria were diminished in TNF receptor 1 (TNFR1) knockout mice, suggesting that these LPS effects are mediated by TNF-α activation of TNFR1. Indeed, intravenous administration of TNF decreased GFR and led to loss of glomerular endothelial cell fenestrae, increased fenestrae diameter, and damage to the glomerular endothelial surface layer. LPS treatment decreased kidney expression of vascular endothelial growth factor (VEGF). Thus, our findings confirm the important role of glomerular endothelial injury, possibly by a decreased VEGF level, in the development and progression of AKI and albuminuria in the LPS model of sepsis in the mouse.

  14. Persistent activation of autophagy in kidney tubular cells promotes renal interstitial fibrosis during unilateral ureteral obstruction

    Science.gov (United States)

    Livingston, Man J.; Ding, Han-Fei; Huang, Shuang; Hill, Joseph A.; Yin, Xiao-Ming; Dong, Zheng

    2016-01-01

    ABSTRACT Renal fibrosis is the final, common pathway of end-stage renal disease. Whether and how autophagy contributes to renal fibrosis remains unclear. Here we first detected persistent autophagy in kidney proximal tubules in the renal fibrosis model of unilateral ureteral obstruction (UUO) in mice. UUO-associated fibrosis was suppressed by pharmacological inhibitors of autophagy and also by kidney proximal tubule-specific knockout of autophagy-related 7 (PT-Atg7 KO). Consistently, proliferation and activation of fibroblasts, as indicated by the expression of ACTA2/α-smooth muscle actin and VIM (vimentin), was inhibited in PT-Atg7 KO mice, so was the accumulation of extracellular matrix components including FN1 (fibronectin 1) and collagen fibrils. Tubular atrophy, apoptosis, nephron loss, and interstitial macrophage infiltration were all inhibited in these mice. Moreover, these mice showed a specific suppression of the expression of a profibrotic factor FGF2 (fibroblast growth factor 2). In vitro, TGFB1 (transforming growth factor β 1) induced autophagy, apoptosis, and FN1 accumulation in primary proximal tubular cells. Inhibition of autophagy suppressed FN1 accumulation and apoptosis, while enhancement of autophagy increased TGFB1-induced-cell death. These results suggest that persistent activation of autophagy in kidney proximal tubules promotes renal interstitial fibrosis during UUO. The profibrotic function of autophagy is related to the regulation on tubular cell death, interstitial inflammation, and the production of profibrotic factors. PMID:27123926

  15. Alpha-lipoic acid protects cardiomyocytes against hypoxia/reoxygenation injury by inhibiting autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xueming; Chen, Aihua, E-mail: aihuachen2012@sina.com; Yang, Pingzhen; Song, Xudong; Liu, Yingfeng; Li, Zhiliang; Wang, Xianbao; Wang, Lizi; Li, Yunpeng

    2013-11-29

    Highlights: •We observed the cell viability and death subjected to H/R in H9c2 cardiomyocytes. •We observed the degree of autophagy subjected to H/R in H9c2 cardiomyocytes. •LA inhibited the degree of autophagy in parallel to the enhanced cell survival. •LA inhibited the autophagy in parallel to the decreased total cell death. •We concluded that LA protected cardiomyocytes against H/R by inhibiting autophagy. -- Abstract: Hypoxia/reoxygenation (H/R) is an important in vitro model for exploring the molecular mechanisms and functions of autophagy during myocardial ischemia/reperfusion (I/R). Alpha-lipoic acid (LA) plays an important role in the etiology of cardiovascular disease. Autophagy is widely implicated in myocardial I/R injury. We assessed the degree of autophagy by pretreatment with LA exposed to H/R in H9c2 cell based on the expression levels of Beclin-1, LC3II/LC3I, and green fluorescent protein-labeled LC3 fusion proteins. Autophagic vacuoles were confirmed in H9c2 cells exposed to H/R using transmission electron microscopy. Our findings indicated that pretreatment with LA inhibited the degree of autophagy in parallel to the enhanced cell survival and decreased total cell death in H9c2 cells exposed to H/R. We conclude that LA protects cardiomyocytes against H/R injury by inhibiting autophagy.

  16. Multiple Roles of Autophagy in the Sorafenib Resistance of Hepatocellular Carcinoma

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    Ting Sun

    2017-11-01

    Full Text Available Hepatocellular carcinoma (HCC is the second leading cause of cancer-related death worldwide, and prognosis remains unsatisfactory since the disease is often diagnosed at the advanced stages. Currently, the multikinase inhibitor sorafenib is the only drug approved for the treatment of advanced HCC. However, primary or acquired resistance to sorafenib develops, generating a roadblock in HCC therapy. Autophagy is an intracellular lysosomal pathway involved in protein and organelle degradation, with an astonishing number of connections to human disease and physiology. Current understanding of the role of autophagy in the progression of cancer and the response to cancer therapy remains controversial. Sorafenib is able to induce autophagy in HCC, but the effect of autophagy is indistinct. Some studies established that sorafenib-induced autophagy serves as a pro-survival response. However, other studies found that sorafenib-induced autophagy improves the lethality of sorafenib against HCC cells. The mechanisms underlying autophagy and sorafenib resistance remain elusive. The purpose of this review is to summarize the progress of research focused on autophagy and sorafenib resistance and to update current knowledge of how cellular autophagy impacts sorafenib sensitivity in HCC treatment.

  17. The role of autophagy in THP-1 macrophages resistance to HIV- vpr-induced apoptosis

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    Zhou, Hua-ying, E-mail: zhouhuaying_2004@126.com; Zheng, Yu-huang; He, Yan; Chen, Zi; He, Bo

    2017-02-01

    Macrophages are resistant to cell death and are one of HIV reservoirs. HIV viral protein Vpr has the potential to promote infection of and survival of macrophages, which could be a highly significant factor in the development and/or maintenance of macrophage viral reservoirs. However, the impact of vpr on macrophages resistance to apoptosis is yet to be comprehended. Autophagy is a cell survival mechanism under stress state. In this study, we investigated whether autophagy is involved in macrophages resistant to vpr-induced apoptosis. Using the THP1 macrophages, we studied the interconnection between macrophages resistance to apoptosis and autophagy. We found that vpr is able to trigger autophagy in transfected THP-1 macrophages confirmed by electron microscopy (EM) and western blot analysis, and inhibition of autophagy with 3MA increased vpr-induced apoptosis. The results indicate that autophagy may be responsible for maintenance of macrophage HIV reservoirs. - Highlights: • HIV Vpr is able to trigger autophagy in transfected THP-1 macrophages. • Autophagy inhibition increases vpr-transfected THP1-macrophages apoptosis. • Autophagy is involved in THP-1 macrophages resistant to vpr-induced apoptosis.

  18. Autophagy regulated by miRNAs in colorectal cancer progression and resistance

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    Andrew Fesler

    2017-01-01

    Full Text Available The catabolic process of autophagy is an essential cellular function that allows for the breakdown and recycling of cellular macromolecules. In recent years, the impact of epigenetic regulation of autophagy by noncoding miRNAs has been recognized in human cancer. In colorectal cancer, autophagy plays critical roles in cancer progression as well as resistance to chemotherapy, and recent evidence demonstrates that miRNAs are directly involved in mediating these functions. In this review, we focus on the recent advancements in the field of miRNA regulation of autophagy in colorectal cancer.

  19. GOLGA2 loss causes fibrosis with autophagy in the mouse lung and liver.

    Science.gov (United States)

    Park, Sungjin; Kim, Sanghwa; Kim, Min Jung; Hong, Youngeun; Lee, Ah Young; Lee, Hyunji; Tran, Quangdon; Kim, Minhee; Cho, Hyeonjeong; Park, Jisoo; Kim, Kwang Pyo; Park, Jongsun; Cho, Myung-Haing

    2018-01-01

    Autophagy is a biological recycling process via the self-digestion of organelles, proteins, and lipids for energy-consuming differentiation and homeostasis. The Golgi serves as a donor of the double-membraned phagophore for autophagosome assembly. In addition, recent studies have demonstrated that pulmonary and hepatic fibrosis is accompanied by autophagy. However, the relationships among Golgi function, autophagy, and fibrosis are unclear. Here, we show that the deletion of GOLGA2, encoding a cis-Golgi protein, induces autophagy with Golgi disruption. The induction of autophagy leads to fibrosis along with the reduction of subcellular lipid storage (lipid droplets and lamellar bodies) by autophagy in the lung and liver. GOLGA2 knockout mice clearly demonstrated fibrosis features such as autophagy-activated cells, densely packed hepatocytes, increase of alveolar macrophages, and decrease of alveolar surfactant lipids (dipalmitoylphosphatidylcholine). Therefore, we confirmed the associations among Golgi function, fibrosis, and autophagy. Moreover, GOLGA2 knockout mice may be a potentially valuable animal model for studying autophagy-induced fibrosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Impaired Autophagy in the Lipid-Storage Disorder Niemann-Pick Type C1 Disease

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    Sovan Sarkar

    2013-12-01

    Full Text Available Autophagy dysfunction has been implicated in misfolded protein accumulation and cellular toxicity in several diseases. Whether alterations in autophagy also contribute to the pathology of lipid-storage disorders is not clear. Here, we show defective autophagy in Niemann-Pick type C1 (NPC1 disease associated with cholesterol accumulation, where the maturation of autophagosomes is impaired because of defective amphisome formation caused by failure in SNARE machinery, whereas the lysosomal proteolytic function remains unaffected. Expression of functional NPC1 protein rescues this defect. Inhibition of autophagy also causes cholesterol accumulation. Compromised autophagy was seen in disease-affected organs of Npc1 mutant mice. Of potential therapeutic relevance is that HP-β-cyclodextrin, which is used for cholesterol-depletion treatment, impedes autophagy, whereas stimulating autophagy restores its function independent of amphisome formation. Our data suggest that a low dose of HP-β-cyclodextrin that does not perturb autophagy, coupled with an autophagy inducer, may provide a rational treatment strategy for NPC1 disease.

  1. Impaired autophagy in the lipid-storage disorder Niemann-Pick type C1 disease.

    Science.gov (United States)

    Sarkar, Sovan; Carroll, Bernadette; Buganim, Yosef; Maetzel, Dorothea; Ng, Alex H M; Cassady, John P; Cohen, Malkiel A; Chakraborty, Souvik; Wang, Haoyi; Spooner, Eric; Ploegh, Hidde; Gsponer, Joerg; Korolchuk, Viktor I; Jaenisch, Rudolf

    2013-12-12

    Autophagy dysfunction has been implicated in misfolded protein accumulation and cellular toxicity in several diseases. Whether alterations in autophagy also contribute to the pathology of lipid-storage disorders is not clear. Here, we show defective autophagy in Niemann-Pick type C1 (NPC1) disease associated with cholesterol accumulation, where the maturation of autophagosomes is impaired because of defective amphisome formation caused by failure in SNARE machinery, whereas the lysosomal proteolytic function remains unaffected. Expression of functional NPC1 protein rescues this defect. Inhibition of autophagy also causes cholesterol accumulation. Compromised autophagy was seen in disease-affected organs of Npc1 mutant mice. Of potential therapeutic relevance is that HP-β-cyclodextrin, which is used for cholesterol-depletion treatment, impedes autophagy, whereas stimulating autophagy restores its function independent of amphisome formation. Our data suggest that a low dose of HP-β-cyclodextrin that does not perturb autophagy, coupled with an autophagy inducer, may provide a rational treatment strategy for NPC1 disease. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Autophagy and Macropinocytosis: Keeping an Eye on the Corneal/Limbal Epithelia.

    Science.gov (United States)

    Peng, Han; Park, Jong Kook; Lavker, Robert M

    2017-01-01

    Autophagy and macropinocytosis are processes that are vital for cellular homeostasis, and help cells respond to stress and take up large amounts of material, respectively. The limbal and corneal epithelia have the machinery necessary to carry out both processes; however, autophagy and macropinocytosis are relatively understudied in these two epithelia. In this Perspectives, we describe the basic principles behind macropinocytosis and autophagy, discuss how these two processes are regulated in the limbal and corneal epithelia, consider how these two processes impact on the physiology of limbal and corneal epithelia, and elaborate on areas of future research in autophagy and macropinocytosis as related to the limbal/corneal epithelia.

  3. Autophagy protects intestinal epithelial cells against deoxynivalenol toxicity by alleviating oxidative stress via IKK signaling pathway.

    Science.gov (United States)

    Tang, Yulong; Li, Jianjun; Li, Fengna; Hu, Chien-An A; Liao, Peng; Tan, Kunrong; Tan, Bie; Xiong, Xia; Liu, Gang; Li, Tiejun; Yin, Yulong

    2015-12-01

    Autophagy is an intracellular process of homeostatic degradation that promotes cell survival under various stressors. Deoxynivalenol (DON), a fungal toxin, often causes diarrhea and disturbs the homeostasis of the intestinal system. To investigate the function of intestinal autophagy in response to DON and associated mechanisms, we firstly knocked out ATG5 (autophagy-related gene 5) in porcine intestinal epithelial cells (IPEC-J2) using CRISPR-Cas9 technology. When treated with DON, autophagy was induced in IPEC-J2 cells but not in IPEC-J2.Atg5ko cells. The deficiency in autophagy increased DON-induced apoptosis in IPEC-J2.atg5ko cells, in part, through the generation of reactive oxygen species (ROS). The cellular stress response can be restored in IPEC-J2.atg5ko cells by overexpressing proteins involved in protein folding. Interestingly, we found that autophagy deficiency downregulated the expression of endoplasmic reticulum folding proteins BiP and PDI when IPEC-J2.atg5ko cells were treated with DON. In addition, we investigated the molecular mechanism of autophagy involved in the IKK, AMPK, and mTOR signaling pathway and found that Bay-117082 and Compound C, specific inhibitors for IKK and AMPK, respectively, inhibited the induction of autophagy. Taken together, our results suggest that autophagy is pivotal for protection against DON in pig intestinal cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Hijacker of the Antitumor Immune Response: Autophagy Is Showing Its Worst Facet.

    Science.gov (United States)

    Viry, Elodie; Noman, Muhammad Zaeem; Arakelian, Tsolère; Lequeux, Audrey; Chouaib, Salem; Berchem, Guy; Moussay, Etienne; Paggetti, Jérôme; Janji, Bassam

    2016-01-01

    Macroautophagy (hereafter referred to as autophagy) is a housekeeping process constitutively executed at basal level in all cells to promote cellular homeostasis by regulating organelle and protein turnover. However, autophagy deregulation caused by several stress factors, such as hypoxia, is prevalent in many cancers. It is now well established that autophagy can act as tumor suppressor or tumor promoter depending on tumor type, stage, and genetic context. In developed tumors, autophagy promotes the survival of cancer cells and therefore operates as a cell resistance mechanism. Emerging evidence point to the prominent role of autophagy in disabling the antitumor immune response by multiple overlapping mechanisms leading to tumor escape from immune cell attack mediated by both natural killer cells and cytotoxic T-lymphocytes. Such a role has inspired significant interest in applying anti-autophagy therapies as an entirely new approach to overcome tumor escape from immune surveillance, which constitutes so far a major challenge in developing more effective cancer immunotherapies. In this review, we will summarize recent reports describing how tumor cells, by activating autophagy, manage to hijack the immune system. In particular, we will focus on the emerging role of hypoxia-induced autophagy in shaping the antitumor immune response and in allowing tumor cells to outmaneuver an effective immune response and escape immunosurveillance. In keeping with this, we strongly believe that autophagy represents an attractive future therapeutic target to develop innovative and effective cancer immunotherapeutic approaches.

  5. 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

    Ancient autophagy pathways are emerging as key defense modules in host eukaryotic cells against microbial pathogens. Apart from actively eliminating intracellular intruders, autophagy is also responsible for cell survival, for example by reducing the deleterious effects of endoplasmic reticulum...... documented, but how autophagy contributes to plant innate immunity and cell death is not that clear. A few research reports have appeared recently to shed light on the roles of autophagy in plant-pathogen interactions and in disease-associated host cell death. We present a first attempt to reconcile...

  6. Autophagy: an adaptive metabolic response to stress shaping the antitumor immunity.

    Science.gov (United States)

    Viry, Elodie; Paggetti, Jerome; Baginska, Joanna; Mgrditchian, Takouhie; Berchem, Guy; Moussay, Etienne; Janji, Bassam

    2014-11-01

    Several environmental-associated stress conditions, including hypoxia, starvation, oxidative stress, fast growth and cell death suppression, modulate both cellular metabolism and autophagy to enable cancer cells to rapidly adapt to environmental stressors, maintain proliferation and evade therapies. It is now widely accepted that autophagy is essential to support cancer cell growth and metabolism and that metabolic reprogramming in cancer can also favor autophagy induction. Therefore, this complex interplay between autophagy and tumor cell metabolism will provide unique opportunities to identify new therapeutic targets. As the regulation of the autophagic activity is related to metabolism, it is important to elucidate the exact molecular mechanism which drives it and the functional consequence of its activation in the context of cancer therapy. In this review, we will summarize the role of autophagy in shaping the cellular response to an abnormal tumor microenvironment and discuss some recent results on the molecular mechanism by which autophagy plays such a role in the context of the anti-tumor immune response. We will also describe how autophagy activation can behave as a double-edged sword, by activating the immune response in some circumstances, and impairing the anti-tumor immunity in others. These findings imply that defining the precise context-specific role for autophagy in cancer is critical to guide autophagy-based therapeutics which are becoming key strategies to overcome tumor resistance to therapies. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. The interaction between DAP1 and autophagy in the context of human carcinogenesis.

    Science.gov (United States)

    Wazir, Umar; Khanzada, Zubair S; Jiang, Wen G; Sharma, Anup K; Kasem, Abdul; Mokbel, Kefah

    2014-01-01

    Autophagy is an evolutionarily-conserved catabolic process which furthers cell survival, especially in times of nutritional stress. Whilst being by itself a pro-survival mechanism, it has many areas of overlap with apoptosis. Autophagic cell death is recognised as a subset of programmed cell death, with features more typical of autophagy rather than classical apoptosis. The mechanisms preventing autophagy from unravelling into autophagic cell death are still the subject of much controversy. We discuss the current understanding of these mechanisms, including recent research regarding the role of death-associated protein-1 in autophagy and apoptosis.

  8. Protein kinase C β inhibits autophagy and sensitizes cervical cancer Hela cells to cisplatin.

    Science.gov (United States)

    Li, Na; Zhang, Wei

    2017-04-28

    Recently, autophagy has been indicated to play an essential role in various biological events, such as the response of cervical cancer cells to chemotherapy. However, the exact signalling mechanism that regulates autophagy during chemotherapy remains unclear. In the present study, we investigated the regulation by cisplatin on protein kinase C β (PKC β), on B-cell lymphoma 2 (Bcl-2) and on apoptosis in cervical cancer Hela cells. And then we examined the regulation by cisplatin on autophagy and the role of autophagy on the chemotherapy in Hela cells. In addition, the regulation of the PKC β on the autophagy was also investigated. Our results indicated that cisplatin promoted PKC β in Hela cells. The PKC β inhibitor reduced the cisplatin-induced apoptosis, whereas increased the cisplatin-induced autophagy in Hela cells. On the other side, the PKC β overexpression aggravated the cisplatin-induced apoptosis, whereas down-regulated the cisplatin-induced autophagy. Taken together, our study firstly recognized the involvement of PKC β in the cytotoxicity of cisplatin via inhibiting autophagy in cervical cancer cells. We propose that PKC β would sensitize cervical cancer cells to chemotherapy via reducing the chemotherapy induced autophagy in cancer cells. © 2017 The Author(s).

  9. Autophagy in acute leukemias: a double-edged sword with important therapeutic implications.

    Science.gov (United States)

    Evangelisti, Cecilia; Evangelisti, Camilla; Chiarini, Francesca; Lonetti, Annalisa; Buontempo, Francesca; Neri, Luca M; McCubrey, James A; Martelli, Alberto M

    2015-01-01

    Macroautophagy, usually referred to as autophagy, is a degradative pathway wherein cytoplasmatic components such as aggregated/misfolded proteins and organelles are engulfed within double-membrane vesicles (autophagosomes) and then delivered to lysosomes for degradation. Autophagy plays an important role in the regulation of numerous physiological functions, including hematopoiesis, through elimination of aggregated/misfolded proteins, and damaged/superfluous organelles. The catabolic products of autophagy (amino acids, fatty acids, nucleotides) are released into the cytosol from autophagolysosomes and recycled into bio-energetic pathways. Therefore, autophagy allows cells to survive starvation and other unfavorable conditions, including hypoxia, heat shock, and microbial pathogens. Nevertheless, depending upon the cell context and functional status, autophagy can also serve as a death mechanism. The cohort of proteins that constitute the autophagy machinery function in a complex, multistep biochemical pathway which has been partially identified over the past decade. Dysregulation of autophagy may contribute to the development of several disorders, including acute leukemias. In this kind of hematologic malignancies, autophagy can either act as a chemo-resistance mechanism or have tumor suppressive functions, depending on the context. Therefore, strategies exploiting autophagy, either for activating or inhibiting it, could find a broad application for innovative treatment of acute leukemias and could significantly contribute to improved clinical outcomes. These aspects are discussed here after a brief introduction to the autophagic molecular machinery and its roles in hematopoiesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Mouse Norovirus infection promotes autophagy induction to facilitate replication but prevents final autophagosome maturation

    Energy Technology Data Exchange (ETDEWEB)

    O’Donnell, Tanya B. [Department of Microbiology and Immunology, at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne 3010 (Australia); Hyde, Jennifer L. [School of Chemical and Biological Sciences, University of Queensland, St. Lucia, Brisbane, Queensland 4072 (Australia); Mintern, Justine D. [Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne 3010 (Australia); Mackenzie, Jason M., E-mail: jason.mackenzie@unimelb.edu.au [Department of Microbiology and Immunology, at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne 3010 (Australia)

    2016-05-15

    Autophagy is a cellular process used to eliminate intracellular pathogens. Many viruses however are able to manipulate this cellular process for their own advantage. Here we demonstrate that Mouse Norovirus (MNV) infection induces autophagy but does not appear to utilise the autophagosomal membrane for establishment and formation of the viral replication complex. We have observed that MNV infection results in lipidation and recruitment of LC3 to the autophagosome membrane but prevents subsequent fusion of the autophagosomes with lysosomes, as SQSTM1 (an autophagy receptor) accumulates and Lysosome-Associated Membrane Protein1 is sequestered to the MNV replication complex (RC) rather than to autophagosomes. We have additionally observed that chemical modulation of autophagy differentially affects MNV replication. From this study we can conclude that MNV infection induces autophagy, however suppresses the final maturation step of this response, indicating that autophagy induction contributes to MNV replication independently of RC biogenesis. - Highlights: • MNV induces autophagy in infected murine macrophages. • MNV does not utilise autophagosomal membranes for replication. • The MNV-induced autophagosomes do not fuse with lysosomes. • MNV sequesters SQSTM1 to prevent autophagy degradation and turnover. • Chemical modulation of autophagy enhances MNV replication.

  11. A role for autophagy in the extension of lifespan by dietary restriction in C. elegans.

    Directory of Open Access Journals (Sweden)

    Malene Hansen

    2008-02-01

    Full Text Available In many organisms, dietary restriction appears to extend lifespan, at least in part, by down-regulating the nutrient-sensor TOR (Target Of Rapamycin. TOR inhibition elicits autophagy, the large-scale recycling of cytoplasmic macromolecules and organelles. In this study, we asked whether autophagy might contribute to the lifespan extension induced by dietary restriction in C. elegans. We find that dietary restriction and TOR inhibition produce an autophagic phenotype and that inhibiting genes required for autophagy prevents dietary restriction and TOR inhibition from extending lifespan. The longevity response to dietary restriction in C. elegans requires the PHA-4 transcription factor. We find that the autophagic response to dietary restriction also requires PHA-4 activity, indicating that autophagy is a transcriptionally regulated response to food limitation. In spite of the rejuvenating effect that autophagy is predicted to have on cells, our findings suggest that autophagy is not sufficient to extend lifespan. Long-lived daf-2 insulin/IGF-1 receptor mutants require both autophagy and the transcription factor DAF-16/FOXO for their longevity, but we find that autophagy takes place in the absence of DAF-16. Perhaps autophagy is not sufficient for lifespan extension because although it provides raw material for new macromolecular synthesis, DAF-16/FOXO must program the cells to recycle this raw material into cell-protective longevity proteins.

  12. 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

  13. Membrane proteomics of phagosomes suggests a connection to autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Shui, Wenqing; Sheu, Leslie; Liu, Jun; Smart, Brian; Petzold, Christopher J.; Hsieh, Tsung-yen; Pitcher, Austin; Keasling*, Jay D.; Bertozzi*, Carolyn R.

    2008-11-25

    Phagocytosis is the central process by which macrophage cellsinternalize and eliminate infectious microbes as well as apoptoticcells. During maturation, phagosomes containing engulfed particlesfuse with various endosomal compartments through theaction of regulatory molecules on the phagosomal membrane. Inthis study, we performed a proteomic analysis of the membranefraction from latex bead-containing (LBC) phagosomes isolatedfrom macrophages. The profile, which comprised 546 proteins,suggests diverse functions of the phagosome and potential connectionsto secretory processes, toll-like receptor signaling, andautophagy. Many identified proteins were not previously knownto reside in the phagosome. We characterized several proteins inLBC phagosomes that change in abundance on induction of autophagy,a process that has been previously implicated in the hostdefense against microbial pathogens. These observations suggestcrosstalk between autophagy and phagocytosis that may be relevantto the innate immune response of macrophages.

  14. THE ROLE OF AUTOPHAGY AND ANGIOGENESIS IN COLORECTAL CANCER

    Directory of Open Access Journals (Sweden)

    K. V. Rachkovsky

    2017-01-01

    Full Text Available The purpose of the study was a review of available data on the role of autophagy and angiogenesis in the development, progression and prognosis of colorectal cancer. Material and methods. Databases searched were Medline, Cochrane Library and Elibrary. Of 340 studies, 48 were used to write a systematic review. Results. To date, there is a variety of prognostic markers used in the study of pathogenesis, diagnosis and treatment of colorectal cancer. The review describes the molecular mechanisms of the participation of various proteins of autophagy and angiogenesis in the pathogenesis and progression of colorectal cancer, and the potential importance of their use in clinical practice is presented. Conclusion. Many of the existing markers can be used not only in assessing the prognosis, but also sensitivity to chemotherapy. However, the contradictory results of studies with respect to certain proteins require further study, validation, and subsequent introduction into practice. 

  15. Autophagy and Retromer Components in Plant Innate Immunity

    DEFF Research Database (Denmark)

    Munch, David

    Innate immunity depends on the recognition of pathogens and subsequent regulation of complex interactions that ultimately leads to production of compounds to deter microbial innovation. This thesis presents different aspects of immunity-associated cell death with focus on autophagy in the plant...... metabolism and its role in plant innate immunity will be presented. A homolog of ACD11 in humans is FOUR-PHOSPHATE ADAPTOR PROTEIN2 (FAPP2) and it has also been shown to be involved in cell death regulation in human Jurkat T cells. The data presented here show that FAPP2 does not appear to be involved......, a component of the retromer complex, was discovered as a relatively weak suppressor. Here I show redundancy between the three VPS35 homologs present in Arabidopsis in regulation of immunity-associated cell death, with a focus on the catabolic pathway autophagy. In addition a role for ACD11 in sphingolipid...

  16. Autophagy--A free meal in sickness-associated anorexia.

    Science.gov (United States)

    van Niekerk, Gustav; Loos, Ben; Nell, Theo; Engelbrecht, Anna-Mart

    2016-01-01

    Activation of the immune system is metabolically costly, yet a hallmark of an infection is a reduction in appetite with a subsequent reduction in metabolite provision. What is the functional value of decreasing nutrient intake when an infection imposes large demands on metabolic parameters? Here, we propose that sickness-associated anorexia (SAA) upregulates the ancient process of autophagy systemically, thereby profoundly controlling not only immune- but also nonimmune-competent cells. This allows an advanced impact on the resolution of an infection through direct pathogen killing, enhancement of epitope presentation and the contribution toward the clearance of noxious factors. By rendering a 'free meal,' autophagy is thus most fundamentally harnessed during an anorexic response in order to promote both host tolerance and resistance. These findings strongly suggest a reassessment of numerous SAA-related clinical applications and a re-evaluation of current efforts in patient care.

  17. Diabetes and the Brain: Oxidative Stress, Inflammation, and Autophagy

    Directory of Open Access Journals (Sweden)

    María Muriach

    2014-01-01

    Full Text Available Diabetes mellitus is a common metabolic disorder associated with chronic complications including a state of mild to moderate cognitive impairment, in particular psychomotor slowing and reduced mental flexibility, not attributable to other causes, and shares many symptoms that are best described as accelerated brain ageing. A common theory for aging and for the pathogenesis of this cerebral dysfunctioning in diabetes relates cell death to oxidative stress in strong association to inflammation, and in fact nuclear factor κB (NFκB, a master regulator of inflammation and also a sensor of oxidative stress, has a strategic position at the crossroad between oxidative stress and inflammation. Moreover, metabolic inflammation is, in turn, related to the induction of various intracellular stresses such as mitochondrial oxidative stress, endoplasmic reticulum (ER stress, and autophagy defect. In parallel, blockade of autophagy can relate to proinflammatory signaling via oxidative stress pathway and NFκB-mediated inflammation.

  18. Glomerular filtration rate by 51chomium and 113mindium labeled EDTA in horses

    International Nuclear Information System (INIS)

    Maliska, C.; D'Almeida, J.; Pellegrini, P.M.; Schimit, T.S.; Pinho, W.R.; Lima, J.E.T.

    2009-01-01

    The glomerular filtration rate was determined in nine healthy horses, six male and three female, aged two to 12-year-old, by means of 51 Cr and 113m In labeled EDTA single injection technique. The glomerular filtration rate was calculated from the plasma disappearance curve and the volume of distribution of the radiotracer, 51 Cr-EDTA or 113m In-EDTA. The result (mean +- standard deviation) was 148.80 +- 26.42 m L.min -1 .100 kg. It is concluded that the measurement of glomerular filtration rate by 51 Cr-EDTA or 113m In-EDTA by single injection technique eliminates the bladder catheterization, and for its simplicity, convenience, accuracy, and low dose of radiation, can be used in horses as a method of choice in clinical routine. (author)

  19. Glomerular filtration rate: estimation from fractional renal accumulation of 99mTc-DTPA (stannous)

    International Nuclear Information System (INIS)

    Gates, G.F.

    1982-01-01

    99mTc diethylenetriaminepentaacetic acid (stannous) is cleared from the blood by glomerular filtration. However, calculation of the glomerular filtration rate has required analysis of serial blood samples drawn over intervals of several hours in order to determine the radionuclide clearance rate. This lengthy procedure can be circumvented by the direct scintigraphic determination of fractional radionuclide accumulation within each kidney, occurring at a specified time interval after radionuclide administration. This value has been correlated with 24 hr creatinine clearance values in a group of hospitalized patients. From these data, a formula was derived allowing for estimation of total glomerular filtration rate, as well as individually for each kidney, without requiring blood samples. This procedure needs only 6 min of patient time

  20. Glomerular nerve endings in corial papillae of the pig lip skin.

    Science.gov (United States)

    Malinovský, L; Pác, L; Krivánková, L

    1982-01-01

    In the tops of corial papillae of the pig lip skin the authors sometimes observed besides typical sensory corpuscles also glomerular nerve endings. They are formed by one axon or they are polyaxon. The nerve fibres are richly branched in the formation. In electronogrammes a large number of axons is visible in cross sections round some of which there are more or less formed lamellous systems up to four lamellae. Between the axons there are nuclei of Schwann cells, on the surface there is a thin capsule of fibrocyte character. In non-primate mammals the typical receptor in the corium of the skin are simple corpuscles, in primates glomerular nerve endings. As concerns sensory corpuscles it is the other way round. The authors are of the opinion that the observed glomerular endings represent morphologically a transitory formation. With respect to the occurrence of lamellous complexes in the glomeruli, they can be considered as equivalent to simple sensory corpuscles with rapid adaptation.

  1. Reduction in non-glomerular renal clearance of the caffeine metabolite 1-methylxanthine by probenecid.

    Science.gov (United States)

    Rengelshausen, J; Göggelmann, C; Burhenne, J; Riedel, K D; Mikus, G; Walter-Sack, I; Haefeli, W E

    2007-08-01

    Urinary caffeine metabolic ratios used to quantify the activity of numerous drug-metabolizing enzymes are an established component of cocktail approaches for metabolic phenotyping. Because in vitro evidence suggests that 1-methylxanthine (1-MX), a major caffeine metabolite, is actively secreted into urine by organic anion transporters (hOATs), coadministration of renal hOAT inhibitors like probenecid may impair these procedures. In a randomized, placebo-controlled, double-blind crossover design, single oral doses of 300 mg caffeine with oral coadministration of placebo or 500 mg probenecid 3 times daily for 2 days were administered to 7 healthy men. The plasma and urine concentrations of caffeine and its major metabolites 1,7-dimethylxanthine (1,7-DMX) and 1-MX were determined by high-performance liquid chromatography. Coadministration of probenecid resulted in a 34% reduction of the renal clearance of 1-MX (mean +/- SD 190 +/- 42 versus 290 +/- 83 ml min(-1), 95% CI on difference 0.2, 200, p = 0.04) with a 41% reduction in its estimated non-glomerular clearance. The renal clearances of caffeine and 1,7-DMX and the area under the plasma concentration-time curves of all substances were not significantly changed. 1-MX undergoes renal tubular secretion which is substantially reduced by probenecid, possibly due to inhibition of renal hOATs. This inhibition may explain the influence of probenecid on urinary caffeine metabolic ratios and, thus, its impact on the assessment of enzyme activities. It also suggests that 1-MX might serve as a model substrate for the renal tubular transport of organic anions.

  2. 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.

  3. [Cystatin C as a marker of glomerular filtration rate in patients with ovarian cancer].

    Science.gov (United States)

    Bodnar, Lubomir; Wcisło, Gabriel B; elichowski, Grzegorz; Raczka, Anna; Wańkowicz, Zofia; Szczylik, Cezary

    2008-04-01

    Cystatin C, a cysteine protease inhibitor, has been recommended as a new marker of glomerular filtration rate (GFR). THE AIM OF STUDY We investigated significance of cystatin C in assessment of GFR and its influence on overall survival (OS) in patients with ovarian cancer (OC). We prospectively included consecutive patients with OC, who after surgery were qualified to first line chemotherapy according to the following protocol: cisplatin 75 mg/m2 and 24-hour infusion of paclitaxel 135 mg/m2 every three weeks. We assessed: serum levels of creatinine (Cr), cystatin C (Cys C), creatinine clearance (ClCr) calculated from 24-hour urine collection, GFR estimated according to Cocroft-Gault (CG) and Modification Diet of Renal Disease (MDRD) formulas. Age median of 37 patients enrolled into this study was 54 years (range from 28 to 68). We noted correlation between cystatin C and CrCl (R Spearman= -0.36; p = 0.03). We did not state any correlation between Cys C and another markers of GFR as: serum creatinine, CG, MDRD. However, we observed correlation between Cys C and measured tumor mass seeing in spiral CT-scan (diameter more than 1 cm) after surgery (R Spearman = 0.4; p = 0.01) and serum level of marker CA 125 (R Spearman= 0.4; p = 0.03). We didn't find any statistical correlation between values of serum Cys C (using median's as cutoff values) in overall survival of our patients (log-rank test, p = 0.9). Serum cystatin C level in patient with ovarian cancer is both the poor marker of GFR and has not prognostic value in the course of cancer after surgery with further primary chemotherapy. The explanation of this phenomenon could rely on the presence of residual ovarian cancer.

  4. Prognostic impact of autophagy biomarkers for cutaneous melanoma.

    Directory of Open Access Journals (Sweden)

    Diana Yao Li Tang

    2016-11-01

    Full Text Available Prognosis and survival for malignant melanoma is highly dependent on early diagnosis and treatment. While the American Joint Committee on Cancer (AJCC criteria provides a means of staging melanomas and guiding treatment approaches, it is unable to identify the risk of disease progression of early stage tumours or provide reliable stratification for novel adjuvant therapies. The demand for credible prognostic/companion biomarkers able to identify high risk melanoma subgroups as well as guide more effective personalised/precision based therapy is therefore of paramount importance. Autophagy, the principle lysosomal-mediated process for the degradation/recycling of cellular debris, is a hot topic in cancer medicine and observations of its deregulation in melanoma have brought its potential as a prognostic biomarker to the forefront of current research. Key regulatory proteins, including Atg8/microtubule-associated light chain 3 (LC3 and BECN1 (Beclin 1 have been proposed as potential prognostic biomarkers. However, given the dynamic nature of autophagy, their expression in vitro does not translate to their use as a prognostic biomarker for melanoma in vivo. We have recently identified the expression levels of Sequestosome1/SQSTM1 (p62 and activating molecule in Beclin 1 regulated autophagy protein 1 (AMBRA1 as novel independent prognostic biomarkers for early stage melanomas. While increasing followed by subsequent decreasing levels of p62 expression reflects the paradoxical role of autophagy in melanoma, expression levels additionally define a novel prognostic biomarker for AJCC stage II tumours. Conversely, loss of AMBRA1 in the epidermis overlying primary melanomas defines a novel prognostic biomarker for AJCC stage I tumours. Collectively, the definition of AMBRA1 and p62 as prognostic biomarkers for early stage melanomas provides novel and accurate means through which to identify tumours at risk of disease progression, facilitating earlier

  5. Autophagy, inflammation and innate immunity in inflammatory myopathies.

    Directory of Open Access Journals (Sweden)

    Cristina Cappelletti

    Full Text Available Autophagy has a large range of physiological functions and its dysregulation contributes to several human disorders, including autoinflammatory/autoimmune diseases such as inflammatory myopathies (IIMs. In order to better understand the pathogenetic mechanisms of these muscular disorders, we sought to define the role of autophagic processes and their relation with the innate immune system in the three main subtypes of IIM, specifically sporadic inclusion body myositis (sIBM, polymyositis (PM, dermatomyositis (DM and juvenile dermatomyositis (JDM. We found that although the mRNA transcript levels of the autophagy-related genes BECN1, ATG5 and FBXO32 were similar in IIM and controls, autophagy activation in all IIM subgroups was suggested by immunoblotting results and confirmed by immunofluorescence. TLR4 and TLR3, two potent inducers of autophagy, were highly increased in IIM, with TLR4 transcripts significantly more expressed in PM and DM than in JDM, sIBM and controls, and TLR3 transcripts highly up-regulated in all IIM subgroups compared to controls. Co-localization between autophagic marker, LC3, and TLR4 and TLR3 was observed not only in sIBM but also in PM, DM and JDM muscle tissues. Furthermore, a highly association with the autophagic processes was observed in all IIM subgroups also for some TLR4 ligands, endogenous and bacterial HSP60, other than the high-mobility group box 1 (HMGB1. These findings indicate that autophagic processes are active not only in sIBM but also in PM, DM and JDM, probably in response to an exogenous or endogenous 'danger signal'. However, autophagic activation and regulation, and also interaction with the innate immune system, differ in each type of IIM. Better understanding of these differences may lead to new therapies for the different IIM types.

  6. Overcoming Autophagy to Induce Apoptosis in Castration Resistant Prostate Cancer

    Science.gov (United States)

    2015-10-01

    AWARD NUMBER: W81XWH-12-1-0529 TITLE: Overcoming Autophagy to Induce Apoptosis in Castration Resistant Prostate Cancer PRINCIPAL...survival mechanism and led cells to undergo apoptosis . Survival mechanisms elicited by CRPC C4-2B cells when treated with Enza may be blocked by...Targeting cancer cell metabolism: the combination of metformin and 2-deoxyglucose induces p53-dependent apoptosis in prostate cancer cells. Cancer

  7. Erythroid precursors from patients with low-risk myelodysplasia demonstrate ultrastructural features of enhanced autophagy of mitochondria

    NARCIS (Netherlands)

    Houwerzijl, E. J.; Pol, H-W D.; Blom, N. R.; van der Want, J. J. L.; de Wolf, J. Thm; Vellenga, E.

    Recent studies in erythroid cells have shown that autophagy is an important process for the physiological clearance of mitochondria during terminal differentiation. However, autophagy also plays an important role in removing damaged and dysfunctional mitochondria. Defective mitochondria and impaired

  8. Alix differs from ESCRT proteins in the control of autophagy

    International Nuclear Information System (INIS)

    Petiot, Anne; Strappazzon, Flavie; Chatellard-Causse, Christine; Blot, Beatrice; Torch, Sakina; Jean-Marc Verna; Sadoul, Remy

    2008-01-01

    Alix/AIP1 is a cytosolic protein that regulates cell death through mechanisms that remain unclear. Alix binds to two protein members of the so-called Endosomal Sorting Complex Required for Transport (ESCRT), which facilitates membrane fission events during multivesicular endosome formation, enveloped virus budding and cytokinesis. Alix itself has been suggested to participate in these cellular events and is thus often considered to function in the ESCRT pathway. ESCRT proteins were recently implicated in autophagy, a process involved in bulk degradation of cytoplasmic constituents in lysosomes, which can also participate in cell death. In this study, we shown that, unlike ESCRT proteins, Alix is not involved in autophagy. These results strongly suggest that the capacity of several mutants of Alix to block both caspase-dependent and independent cell death does not relate to their capacity to modulate autophagy. Furthermore, they reinforce the conclusion of other studies demonstrating that the role of Alix is different from that of classical ESCRT proteins

  9. Autophagy induction by histone deacetylase inhibitors inhibits HIV type 1.

    Science.gov (United States)

    Campbell, Grant R; Bruckman, Rachel S; Chu, Yen-Lin; Spector, Stephen A

    2015-02-20

    Histone deacetylase inhibitors (HDACi) are being evaluated in a "shock-and-kill" therapeutic approach to reverse human immunodeficiency virus type-1 (HIV) latency from CD4(+) T cells. Using this approach, HDACi have induced HIV RNA synthesis in latently infected cells from some patients. The hope is that the increase in viral production will lead to killing of the infected cell either by the virus itself or by the patient's immune system, a "sterilizing cure." Although administered within the context of combination antiretroviral therapy, the infection of bystander cells remains a concern. In this study, we investigated the effect of HDACi (belinostat, givinostat, panobinostat, romidepsin, and vorinostat) on the productive infection of macrophages. We demonstrate that the HDACi tested do not alter the initial susceptibility of macrophages to HIV infection. However, we demonstrate that HDACi decrease HIV release from macrophages in a dose-dependent manner (belinostat the canonical autophagy pathway. This mechanism involves unc-51-like autophagy-activating kinase 1 (ULK1) and the inhibition of the mammalian target of rapamycin and requires the formation of autophagosomes and their maturation into autolysosomes in the absence of increased cell death. These data provide further evidence in support of a role for autophagy in the control of HIV infection and suggest that careful consideration of off-target effects will be essential if HDACi are to be a component of a multipronged approach to eliminate latently infected cells. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Midgut morphological changes and autophagy during metamorphosis in sand flies.

    Science.gov (United States)

    Malta, Juliana; Heerman, Matthew; Weng, Ju Lin; Fernandes, Kenner M; Martins, Gustavo Ferreira; Ramalho-Ortigão, Marcelo

    2017-06-01

    During metamorphosis, holometabolous insects undergo significant remodeling of their midgut and become able to cope with changes in dietary requirements between larval and adult stages. At this stage, insects must be able to manage and recycle available food resources in order to develop fully into adults, especially when no nutrients are acquired from the environment. Autophagy has been previously suggested to play a crucial role during metamorphosis of the mosquito. Here, we investigate the overall morphological changes of the midgut of the sand fly during metamorphosis and assess the expression profiles of the autophagy-related genes ATG1, ATG6, and ATG8, which are associated with various steps of the autophagic process. Morphological changes in the midgut start during the fourth larval instar, with epithelial degeneration followed by remodeling via the differentiation of regenerative cells in pre-pupal and pupal stages. The changes in the midgut epithelium are paired with the up-regulation of ATG1, ATG6 and ATG8 during the larva-adult transition. Vein, a putative epidermal growth factor involved in regulating epithelial midgut regeneration, is also up-regulated. Autophagy has further been confirmed in sand flies via the presence of autophagosomes residing within the cytoplasmic compartment of the pupal stages. An understanding of the underlying mechanisms of this process should aid the future management of this neglected tropical vector.

  11. Regulation of endoplasmic reticulum turnover by selective autophagy.

    Science.gov (United States)

    Khaminets, Aliaksandr; Heinrich, Theresa; Mari, Muriel; Grumati, Paolo; Huebner, Antje K; Akutsu, Masato; Liebmann, Lutz; Stolz, Alexandra; Nietzsche, Sandor; Koch, Nicole; Mauthe, Mario; Katona, Istvan; Qualmann, Britta; Weis, Joachim; Reggiori, Fulvio; Kurth, Ingo; Hübner, Christian A; Dikic, Ivan

    2015-06-18

    The endoplasmic reticulum (ER) is the largest intracellular endomembrane system, enabling protein and lipid synthesis, ion homeostasis, quality control of newly synthesized proteins and organelle communication. Constant ER turnover and modulation is needed to meet different cellular requirements and autophagy has an important role in this process. However, its underlying regulatory mechanisms remain unexplained. Here we show that members of the FAM134 reticulon protein family are ER-resident receptors that bind to autophagy modifiers LC3 and GABARAP, and facilitate ER degradation by autophagy ('ER-phagy'). Downregulation of FAM134B protein in human cells causes an expansion of the ER, while FAM134B overexpression results in ER fragmentation and lysosomal degradation. Mutant FAM134B proteins that cause sensory neuropathy in humans are unable to act as ER-phagy receptors. Consistently, disruption of Fam134b in mice causes expansion of the ER, inhibits ER turnover, sensitizes cells to stress-induced apoptotic cell death and leads to degeneration of sensory neurons. Therefore, selective ER-phagy via FAM134 proteins is indispensable for mammalian cell homeostasis and controls ER morphology and turnover in mice and humans.

  12. Spectral imaging-based methods for quantifying autophagy and apoptosis.

    Science.gov (United States)

    Dolloff, Nathan G; Ma, Xiahong; Dicker, David T; Humphreys, Robin C; Li, Lin Z; El-Deiry, Wafik S

    2011-08-15

    Spectral imaging systems are capable of detecting and quantifying subtle differences in light quality. In this study we coupled spectral imaging with fluorescence and white light microscopy to develop new methods for quantifying autophagy and apoptosis. For autophagy, we employed multispectral imaging to examine spectral changes in the fluorescence of LC3-GFP, a chimeric protein commonly used to track autophagosome formation. We found that punctate autophagosome-associated LC3-GFP exhibited a spectral profile that was distinctly different from diffuse cytosolic LC3-GFP. We then exploited this shift in spectral quality to quantify the amount of autophagosome-associated signal in single cells. Hydroxychloroquine (CQ), an anti-malarial agent that increases autophagosomal number, significantly increased the punctate LC3-GFP spectral signature, providing proof-of-principle for this approach. For studying apoptosis, we employed the Prism and Reflector Imaging Spectroscopy System (PARISS) hyperspectral imaging system to identify a spectral signature for active caspase-8 immunostaining in ex vivo tumor samples. This system was then used to rapidly quantify apoptosis induced by lexatumumab, an agonistic TRAIL-R2/DR5 antibody, in histological sections from a preclinical mouse model. We further found that the PARISS could accurately distinguish apoptotic tumor regions in hematoxylin and eosin-stained sections, which allowed us to quantify death receptor-mediated apoptosis in the absence of an apoptotic marker. These spectral imaging systems provide unbiased, quantitative and fast means for studying autophagy and apoptosis and complement the existing methods in their respective fields.

  13. Autophagy, Innate Immunity and Tissue Repair in Acute Kidney Injury

    Directory of Open Access Journals (Sweden)

    Pu Duann

    2016-05-01

    Full Text Available Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed.

  14. Isoliquiritigenin Induces Autophagy and Inhibits Ovarian Cancer Cell Growth

    Directory of Open Access Journals (Sweden)

    Hsin-Yuan Chen

    2017-09-01

    Full Text Available Ovarian cancer is one of the commonest gynecologic malignancies, which has a poor prognosis for patients at the advanced stage. Isoliquiritigenin (ISL, an active flavonoid component of the licorice plant, previously demonstrated antioxidant, anti-inflammatory, and tumor suppressive effects. In this study, we investigated the antitumor effect of ISL on human ovarian cancer in vitro using the human ovarian cancer cell lines, OVCAR5 and ES-2, as model systems. Our results show that ISL significantly inhibited the viability of cancer cells in a concentration- and time-dependent manner. Flow cytometry analysis indicated that ISL induced G2/M phase arrest. Furthermore, the expression of cleaved PARP, cleaved caspase-3, Bax/Bcl-2 ratio, LC3B-II, and Beclin-1 levels were increased in western blot analysis. To clarify the role of autophagy and apoptosis in the effect of ISL, we used the autophagy inhibitor—3-methyladenine (3-MA to attenuate the punctate fluorescence staining pattern of the p62/sequestosome 1 (SQSTM1, red fluorescence and LC3 (green fluorescence proteins after ISL treatment, and 3-MA inhibited the cytotoxicity of ISL. These findings provide new information about the link between ISL-induced autophagy and apoptosis and suggest that ISL is a candidate agent for the treatment of human ovarian cancer.

  15. MOLECULAR DETERMINANTS OF SELECTIVE CLEARANCE OF PROTEIN INCLUSIONS BY AUTOPHAGY

    Science.gov (United States)

    Wong, Esther; Bejarano, Eloy; Rakshit, Moumita; Lee, Karen; Hanson, Hugo H.; Zaarur, Nava; Phillips, Greg R.; Sherman, Michael Y.; Cuervo, Ana Maria

    2012-01-01

    Protein quality control is essential for cellular survival. Failure to eliminate pathogenic proteins leads to their intracellular accumulation in the form of protein aggregates. Autophagy can recognize protein aggregates and degrade them in lysosomes. However, some aggregates escape the autophagic surveillance. Here we analyze the autophagic degradation of different types of aggregates of synphilin-1 (Sph1), a protein often found in pathogenic protein inclusions. We show that small Sph1 aggregates and large aggresomes are differentially targeted by constitutive and inducible autophagy. Furthermore, we identify a region in Sph1 necessary for its own basal and inducible aggrephagy, and sufficient for the degradation of other pro-aggregating proteins. Although the presence of this peptide is sufficient for basal aggrephagy, inducible aggrephagy requires its ubiquitination, which diminishes protein mobility on the surface of the aggregate and favors the recruitment and assembly of the protein complexes required for autophagosome formation. Our study reveals different mechanisms for cells to cope with aggregate proteins via autophagy and supports the idea that autophagic susceptibility of prone-to-aggregate proteins may not depend on the nature of the aggregating proteins per se but on their dynamic properties in the aggregate. PMID:23212369

  16. Eyeing autophagy and macropinocytosis in the corneal/limbal epithelia.

    Science.gov (United States)

    Peng, Han; Park, Jong Kook; Lavker, Robert M

    2017-05-04

    Macroautophagy/autophagy is vital for cellular homeostasis and helps cells respond to various stress situations. Macropinocytosis enables cells to nonselectively engulf and take up large volumes of fluid and is known to supply amino acids to cells. The stem cell-enriched limbal epithelium has the machinery necessary to carry out both autophagy and macropinocytosis; however, both processes are relatively understudied in this tissue. We have demonstrated that these processes are linked via MIR103-MIR107, a microRNA family that is limbal epithelial-preferred. Loss of MIR103-MIR107 causes the accumulation of large vacuoles that originate, in part, from a dysregulation in macropinocytosis via activation of SRC-RAS signaling. We found that these vacuoles were autophagic in nature and retained in cells due to inappropriate regulation of end-stage autophagy. Specifically, MIR103-MIR107 regulates diacylglycerol-PRKC/protein kinase C and CDK5 (cyclin dependent kinase 5) signaling, which enables DNM1 (dynamin 1) to function in vacuole clearance.

  17. Macrophage migration inhibitory factor induces vascular leakage via autophagy

    Directory of Open Access Journals (Sweden)

    Hong-Ru Chen

    2015-01-01

    Full Text Available Vascular leakage is an important feature of acute inflammatory shock, which currently has no effective treatment. Macrophage migration inhibitory factor (MIF is a pro-inflammatory cytokine that can induce vascular leakage and plays an important role in the pathogenesis of shock. However, the mechanism of MIF-induced vascular leakage is still unclear. In this study, using recombinant MIF (rMIF, we demonstrated that MIF induced disorganization and degradation of junction proteins and increased the permeability of human endothelial cells in vitro. Western blotting analysis showed that rMIF treatment induced LC3 conversion and p62 degradation. Inhibition of autophagy with a PI3K inhibitor (3-MA, a ROS scavenger (NAC or autophagosomal-lysosomal fusion inhibitors (bafilomycin A1 and chloroquine rescued rMIF-induced vascular leakage, suggesting that autophagy mediates MIF-induced vascular leakage. The potential involvement of other signaling pathways was also studied using different inhibitors, and the results suggested that MIF-induced vascular leakage may occur through the ERK pathway. In conclusion, we showed that MIF triggered autophagic degradation of endothelial cells, resulting in vascular leakage. Inhibition of MIF-induced autophagy may provide therapeutic targets against vascular leakage in inflammatory shock.

  18. ABIN1 Determines Severity of Glomerulonephritis via Activation of Intrinsic Glomerular Inflammation.

    Science.gov (United States)

    Korte, Erik A; Caster, Dawn J; Barati, Michelle T; Tan, Min; Zheng, Shirong; Berthier, Celine C; Brosius, Frank C; Vieyra, Mark B; Sheehan, Ryan M; Kosiewicz, Michele; Wysoczynski, Marcin; Gaffney, Patrick M; Salant, David J; McLeish, Kenneth R; Powell, David W

    2017-12-01

    Transcription factor NF-κB regulates expression of numerous genes that control inflammation and is activated in glomerular cells in glomerulonephritis (GN). We previously identified genetic variants for a NF-κB regulatory, ubiquitin-binding protein ABIN1 as risk factors for GN in systemic autoimmunity. The goal was to define glomerular inflammatory events controlled by ABIN1 function in GN. Nephrotoxic serum nephritis was induced in wild-type (WT) and ubiquitin-binding deficient ABIN1[D485N] mice, and renal pathophysiology and glomerular inflammatory phenotypes were assessed. Proteinuria was also measured in ABIN1[D485N] mice transplanted with WT mouse bone marrow. Inflammatory activation of ABIN1[D472N] (D485N homolog) cultured human-derived podocytes, and interaction with primary human neutrophils were also assessed. Disruption of ABIN1 function exacerbated proteinuria, podocyte injury, glomerular NF-κB activity, glomerular expression of inflammatory mediators, and glomerular recruitment and retention of neutrophils in antibody-mediated nephritis. Transplantation of WT bone marrow did not prevent the increased proteinuria in ABIN1[D845N] mice. Tumor necrosis factor-stimulated enhanced expression and secretion of NF-κB-targeted proinflammatory mediators in ABIN1[D472N] cultured podocytes compared with WT cells. Supernatants from ABIN1[D472N] podocytes accelerated chemotaxis of human neutrophils, and ABIN1[D472N] podocytes displayed a greater susceptibility to injurious morphologic findings induced by neutrophil granule contents. These studies define a novel role for ABIN1 dysfunction and NF-κB in mediating GN through proinflammatory activation of podocytes. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  19. Defining Glomerular Disease in Mechanistic Terms: Implementing an Integrative Biology Approach in Nephrology.

    Science.gov (United States)

    Mariani, Laura H; Pendergraft, William F; Kretzler, Matthias

    2016-11-07

    Advances in biomedical research allow for the capture of an unprecedented level of genetic, molecular, and clinical information from large patient cohorts, where the quest for precision medicine can be pursued. An overarching goal of precision medicine is to integrate the large-scale genetic and molecular data with deep phenotypic information to identify a new mechanistic disease classification. This classification can ideally be used to meet the clinical goal of the right medication for the right patient at the right time. Glomerular disease presents a formidable challenge for precision medicine. Patients present with similar signs and symptoms, which cross the current disease categories. The diseases are grouped by shared histopathologic features, but individual patients have dramatic variability in presentation, progression, and response to therapy, reflecting the underlying biologic heterogeneity within each glomerular disease category. Despite the clinical challenge, glomerular disease has several unique advantages to building multilayered datasets connecting genetic, molecular, and structural information needed to address the goals of precision medicine in this population. Kidney biopsy tissue, obtained during routine clinical care, provides a direct window into the molecular mechanisms active in the affected organ. In addition, urine is a biofluid ideally suited for repeated measurement from the diseased organ as a liquid biopsy with potential to reflect the dynamic state of renal tissue. In our review, current approaches for large-scale data generation and integration along the genotype-phenotype continuum in glomerular disease will be summarized. Several successful examples of this integrative biology approach within glomerular disease will be highlighted along with an outlook on how achieving a mechanistic disease classification could help to shape glomerular disease research and care in the future. Copyright © 2016 by the American Society of Nephrology.

  20. 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

  1. 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.

  2. A microtechnique for radioisotopic determination of glomerular filtration rate in infants and children

    International Nuclear Information System (INIS)

    Braren, V.; Brill, A.B.; Touya, J.; Goddard, J.

    1982-01-01

    Our experience with a microtechnique using 99 mTc-DTPA for determination of glomerular filtraton rate in 172 children is presented. It is a simple finger-stick method carried out in a four-hour time period by trained nuclear medical personnel. The procedure meets all criteria for precise measurement of glomerular filtration rate, and the radiation dose is low. Proof of accuracy was obtained by comparison of this technique with concomitant 24-hour urinary creatinine clearance in a subset of children

  3. On determinants of glomerular filtration rate after inhibition of proximal tubular reabsorption

    DEFF Research Database (Denmark)

    Leyssac, P P; Karlsen, F M; Holstein-Rathlou, N H

    1994-01-01

    The carbonic anhydrase inhibitor acetazolamide (ACZ) inhibits the absolute rate of proximal reabsorption (APR), causes a reduction in glomerular filtration rate (GFR), and activates the tubuloglomerular feedback mechanism (TGF) resulting in afferent vasoconstriction. The quantitative importance...... of the afferent vasoconstriction for the reduced GFR was tested by addition of a vasodilator during continuous infusion of ACZ. Dopamine caused an increase in renal blood flow (RBF) to pre-ACZ levels. Glomerular capillary pressure (Pgc) and proximal tubular pressure (Pprox) increased in parallel (by 3.1 and 3...

  4. Measurement of glomerular filtration rate by impulse synthesis: Clinical validation and optimization

    International Nuclear Information System (INIS)

    Palagi, B.; Verga, P.; Broggi, A.; Picozzi, R.; Villa, F.; Guzzini, F.; Cozzi, C.; Tomasi, A.

    1988-01-01

    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 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 [de

  5. Determination of glomerular filtration rate and renal plasma flow with radioisotopes

    International Nuclear Information System (INIS)

    Duarte, C.G.; Elveback, L.R.; Liedtke, J.R.

    1983-01-01

    The concept of glomerular filtration and the clearance of inulin and creatinine as an index of renal function, advantages in the use of radioisotopes to measure glomerular filtration rate, and the clearance of /sup 125/I-iothalamate in (1) standard clearance and (2) subcutaneous short-clearance studies. The concept of renal plasma flow and clearance of para-aminohippurate, the use of radioisotopes for the measurement of renal plasma flow, and the clearance of /sup 131/I-Hippuran (iodohippurate sodium). Laboratory procedures for standard renal clearances with labeled iothalamate and Hippuran are given in detail, as is the short iothalamate clearance procedure

  6. Transitory cell attachments in the differentiating glomerular epithelium of the opossum metanephros.

    Science.gov (United States)

    Krause, W J; Cutts, J H

    1980-01-01

    Numerous transitory intercellular attachments are observed between the central, lateral surfaces of adjacent glomerular epithelial cells in the differentiating renal corpuscle. The junctions are characterized by an increased electron density of the adjacent cell membranes and cytoplasm. The intervening intercellular space may contain an amorphous material of moderate electron density. The distribution and position of such temporary cell attachments, together with their modification and subsequent loss during the differentiation of podocytes, suggest that they play an important role in the histogenesis of the glomerular epithelium.

  7. Targeted deletion of Atg5 reveals differential roles of autophagy in keratin K5-expressing epithelia

    Energy Technology Data Exchange (ETDEWEB)

    Sukseree, Supawadee [Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna (Austria); Department of Biochemistry, Faculty of Medicine, Srinakharinwirot University, Bangkok (Thailand); Rossiter, Heidemarie; Mildner, Michael [Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna (Austria); Pammer, Johannes [Institute of Clinical Pathology, Medical University of Vienna, Vienna (Austria); Buchberger, Maria; Gruber, Florian [Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna (Austria); Watanapokasin, Ramida [Department of Biochemistry, Faculty of Medicine, Srinakharinwirot University, Bangkok (Thailand); Tschachler, Erwin [Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna (Austria); Eckhart, Leopold, E-mail: leopold.eckhart@meduniwien.ac.at [Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna (Austria)

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer We generated mice lacking Atg5 and autophagy in keratin K5-positive epithelia. Black-Right-Pointing-Pointer Suppression of autophagy in thymic epithelium was not associated with signs of autoimmunity. Black-Right-Pointing-Pointer Autophagy was required for normal terminal differentiation of preputial gland cells. Black-Right-Pointing-Pointer Autophagy-deficient cells of the preputial glands degraded nuclear DNA prematurely. -- Abstract: Autophagy contributes to the homeostasis of many tissues, yet its role in epithelia is incompletely understood. A recent report proposed that Atg5-dependent autophagy in thymic epithelial cells is essential for their function in the negative selection of self-reactive T-cells and, thus, for the suppression of tissue inflammation. Here we crossed mice carrying floxed alleles of the Atg5 gene with mice expressing the Cre recombinase under the control of the keratin K5 promoter to suppress autophagy in all K5-positive epithelia. The efficiency of autophagy abrogation was confirmed by immunoanalyses of LC3, which was converted to the autophagy-associated LC3-II form in normal but not Atg5-deficient cells, and of p62, which accumulated in Atg5-deficient cells. Mice carrying the epithelium-specific deletion of Atg5 showed normal weight gain, absence of tissue inflammation, and a normal morphology of the thymic epithelium. By contrast, autophagy-deficient epithelial cells of the preputial gland showed aberrant eosinophilic staining in histology and premature degradation of nuclear DNA during terminal differentiation. Taken together, the results of this study suggest that autophagy is dispensable for the suppression of autoimmunity by thymic epithelial cells but essential for normal differentiation of the preputial gland in mice.

  8. Idarubicin induces mTOR-dependent cytotoxic autophagy in leukemic cells

    Energy Technology Data Exchange (ETDEWEB)

    Ristic, Biljana [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Bosnjak, Mihajlo [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Arsikin, Katarina [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Mircic, Aleksandar; Suzin-Zivkovic, Violeta [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Bogdanovic, Andrija [Clinic for Hematology, Clinical Centre of Serbia, School of Medicine, University of Belgrade, Belgrade (Serbia); Perovic, Vladimir [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Martinovic, Tamara; Kravic-Stevovic, Tamara; Bumbasirevic, Vladimir [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Trajkovic, Vladimir, E-mail: vtrajkovic@med.bg.ac.rs [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Harhaji-Trajkovic, Ljubica, E-mail: buajk@yahoo.com [Institute for Biological Research, University of Belgrade, Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade (Serbia)

    2014-08-01

    We investigated if the antileukemic drug idarubicin induces autophagy, a process of programmed cellular self-digestion, in leukemic cell lines and primary leukemic cells. Transmission electron microscopy and acridine orange staining demonstrated the presence of autophagic vesicles and intracellular acidification, respectively, in idarubicin-treated REH leukemic cell line. Idarubicin increased punctuation/aggregation of microtubule-associated light chain 3B (LC3B), enhanced the conversion of LC3B-I to autophagosome-associated LC3B-II in the presence of proteolysis inhibitors, and promoted the degradation of the selective autophagic target p62, thus indicating the increase in autophagic flux. Idarubicin inhibited the phosphorylation of the main autophagy repressor mammalian target of rapamycin (mTOR) and its downstream target p70S6 kinase. The treatment with the mTOR activator leucine prevented idarubicin-mediated autophagy induction. Idarubicin-induced mTOR repression was associated with the activation of the mTOR inhibitor AMP-activated protein kinase and down-regulation of the mTOR activator Akt. The suppression of autophagy by pharmacological inhibitors or LC3B and beclin-1 genetic knockdown rescued REH cells from idarubicin-mediated oxidative stress, mitochondrial depolarization, caspase activation and apoptotic DNA fragmentation. Idarubicin also caused mTOR inhibition and cytotoxic autophagy in K562 leukemic cell line and leukocytes from chronic myeloid leukemia patients, but not healthy controls. By demonstrating mTOR-dependent cytotoxic autophagy in idarubicin-treated leukemic cells, our results warrant caution when considering combining idarubicin with autophagy inhibitors in leukemia therapy. - Highlights: • Idarubicin induces autophagy in leukemic cell lines and primary leukemic cells. • Idarubicin induces autophagy by inhibiting mTOR in leukemic cells. • mTOR suppression by idarubicin is associated with AMPK activation and Akt blockade.

  9. Autophagy facilitates multidrug resistance development through inhibition of apoptosis in breast cancer cells.

    Science.gov (United States)

    Sun, W L; Lan, D; Gan, T Q; Cai, Z W

    2015-01-01

    Acquired multidrug resistance (MDR) is the main mechanism of chemotherapeutic drugs resistance. Nevertheless, the mechanisms of MDR are complex and still not very clear. Recently, including our previous study, several studies have revealed that macroautophagy (here referred to as autophagy) induced by anti-cancer drugs in breast cancer cells may facilitate the development of resistance to epirubicin (EPI), paclitaxel (PTX), tamoxifen or herceptin. Whereas there are a few studies on the relationship between autophagy and MDR, especially the studies designed directly employing induced resistant breast cancer cells. Based on previous study, we explored the relationship between autophagy and MDR. The results showed th