101
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Lay AC, Coward RJM. The Evolving Importance of Insulin Signaling in Podocyte Health and Disease. Front Endocrinol (Lausanne) 2018; 9:693. [PMID: 30524379 PMCID: PMC6258712 DOI: 10.3389/fendo.2018.00693] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/05/2018] [Indexed: 12/17/2022] Open
Abstract
Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease worldwide, occuring in approximately one-third of diabetic patients. One of the earliest hallmarks of DKD is albuminuria, often occurring following disruptions to the glomerular filtration barrier. Podocytes are highly specialized cells with a central role in filtration barrier maintenance; hence, podocyte dysfunction is a major cause of albuminuria in many settings, including DKD. Numerous studies over the last decade have highlighted the importance of intact podocyte insulin responses in the maintenance of podocyte function. This review summarizes our current perspectives on podocyte insulin signaling, highlighting evidence to support the notion that dysregulated podocyte insulin responses contribute toward podocyte damage, particularly during the pathogenesis of DKD.
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102
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Abstract
Inflammasomes influence a diverse range of kidney disease, including acute and chronic kidney diseases, and those mediated by innate and adaptive immunity. Both IL-18 and in particular IL-1β are validated therapeutic targets in several kidney diseases. In addition to leukocyte-derived inflammasomes, renal tissue cells express functional inflammasome components. Furthermore, a range of endogenous substances that directly activate inflammasomes also mediate kidney injury. Many of the functional studies have focussed on the NLRP3 inflammasome, and there is also evidence for the involvement of other inflammasomes in some conditions. While, at least in some disease, the mechanistic details of the involvement of the inflammasome remain to be elucidated, therapies focussed on inflammasomes and their products have potential in treating kidney disease in the future.
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Affiliation(s)
- Holly L Hutton
- Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton, VIC, Australia
| | - Maliha A Alikhan
- Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton, VIC, Australia
| | - A Richard Kitching
- Centre for Inflammatory Diseases, Monash University Department of Medicine, Monash Medical Centre, Clayton, VIC, Australia.
- Department of Nephrology, Monash Health, Clayton, VIC, Australia.
- Department of Paediatric Nephrology, Monash Health, Clayton, VIC, Australia.
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103
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104
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Cybulsky AV, Papillon J, Guillemette J, Belkina N, Patino-Lopez G, Torban E. Ste20-like kinase, SLK, a novel mediator of podocyte integrity. Am J Physiol Renal Physiol 2017; 315:F186-F198. [PMID: 29187370 DOI: 10.1152/ajprenal.00238.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
SLK is essential for embryonic development and may play a key role in wound healing, tumor growth, and metastasis. Expression and activation of SLK are increased in kidney development and during recovery from ischemic acute kidney injury. Overexpression of SLK in glomerular epithelial cells/podocytes in vivo induces injury and proteinuria. Conversely, reduced SLK expression leads to abnormalities in cell adhesion, spreading, and motility. Tight regulation of SLK expression thus may be critical for normal renal structure and function. We produced podocyte-specific SLK-knockout mice to address the functional role of SLK in podocytes. Mice with podocyte-specific deletion of SLK showed reduced glomerular SLK expression and activity compared with control. Podocyte-specific deletion of SLK resulted in albuminuria at 4-5 mo of age in male mice and 8-9 mo in female mice, which persisted for up to 13 mo. At 11-12 mo, knockout mice showed ultrastructural changes, including focal foot process effacement and microvillous transformation of podocyte plasma membranes. Mean foot process width was approximately twofold greater in knockout mice compared with control. Podocyte number was reduced by 35% in knockout mice compared with control, and expression of nephrin, synaptopodin, and podocalyxin was reduced in knockout mice by 20-30%. In summary, podocyte-specific deletion of SLK leads to albuminuria, loss of podocytes, and morphological evidence of podocyte injury. Thus, SLK is essential to the maintenance of podocyte integrity as mice age.
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Affiliation(s)
- Andrey V Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University , Montreal, Quebec , Canada
| | - Joan Papillon
- Department of Medicine, McGill University Health Centre Research Institute, McGill University , Montreal, Quebec , Canada
| | - Julie Guillemette
- Department of Medicine, McGill University Health Centre Research Institute, McGill University , Montreal, Quebec , Canada
| | - Natalya Belkina
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland
| | - Genaro Patino-Lopez
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health , Bethesda, Maryland
| | - Elena Torban
- Department of Medicine, McGill University Health Centre Research Institute, McGill University , Montreal, Quebec , Canada
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105
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Cheng YC, Chen CA, Chen HC. Endoplasmic reticulum stress-induced cell death in podocytes. Nephrology (Carlton) 2017; 22 Suppl 4:43-49. [DOI: 10.1111/nep.13145] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2017] [Indexed: 01/07/2023]
Affiliation(s)
- Yu-Chi Cheng
- Division of Nephrology, Department of Internal Medicine; Kaohsiung Medical University Hospital, Kaohsiung Medical University; Kaohsiung Taiwan
| | - Chien-An Chen
- Division of Nephrology; Sinlau Hospital; Tainan Taiwan
| | - Hung-Chun Chen
- Division of Nephrology, Department of Internal Medicine; Kaohsiung Medical University Hospital, Kaohsiung Medical University; Kaohsiung Taiwan
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106
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Chang YP, Sun B, Han Z, Han F, Hu SL, Li XY, Xue M, Yang Y, Chen L, Li CJ, Chen LM. Saxagliptin Attenuates Albuminuria by Inhibiting Podocyte Epithelial- to-Mesenchymal Transition via SDF-1α in Diabetic Nephropathy. Front Pharmacol 2017; 8:780. [PMID: 29163166 PMCID: PMC5672017 DOI: 10.3389/fphar.2017.00780] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/16/2017] [Indexed: 12/31/2022] Open
Abstract
The dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin has been found to reduce progressive albuminuria, but the exact mechanism of inhibition is unclear. Podocyte epithelial-to-mesenchymal transition (EMT) has emerged as a potential pathway leading to proteinuria in diabetic nephropathy (DN). Stromal cell–derived factor-1α (SDF-1α), one of the substrates of DPP-4, can activate the protein kinase A pathway and subsequently inhibit its downstream effector, transforming growth factor-β1 (TGF-β1), which induces podocyte EMT. Thus, this study was designed to test the hypothesis that saxagliptin reduces progressive albuminuria by preventing podocyte EMT through inhibition of SDF-1α cleavage in DN. The results of a series of assays, including ELISA, western blotting, and immunochemistry/immunofluorescence, showed that saxagliptin treatment obviously ameliorated urinary microalbumin excretion and renal histological changes in high-fat diet/streptozotocin-induced diabetic rats. Furthermore, saxagliptin-treated diabetic rats presented with suppression of DPP-4 activity/protein expression accompanied by restoration of SDF-1α levels, which subsequently hindered NOX2 expression and podocyte EMT. In vitro, we consistently observed that saxagliptin significantly inhibited increased DPP-4 activity/expression, oxidative stress and podocyte EMT. Application of an SDF-1α receptor inhibitor (AMD3100) to cultured podocytes further confirmed the essential role of SDF-1α in podocyte EMT inhibition. In sum, we demonstrated for the first time that saxagliptin treatment plays an essential role in ameliorating progressive DN by preventing podocyte EMT through a SDF-1α-related pathway, suggesting that saxagliptin could offer renoprotection and that SDF-1α might be a potential therapeutic target for DN.
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Affiliation(s)
- Yun-Peng Chang
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Bei Sun
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Zhe Han
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Fei Han
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Shao-Lan Hu
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Xiao-Yu Li
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Mei Xue
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Yang Yang
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Li Chen
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Chun-Jun Li
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Li-Ming Chen
- Key Laboratory of Hormones and Development (Ministry of Health), Tianjin Key Laboratory of Metabolic Diseases, Tianjin Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
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107
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Interaction of CD80 with Neph1: a potential mechanism of podocyte injury. Clin Exp Nephrol 2017; 22:508-516. [PMID: 29022109 DOI: 10.1007/s10157-017-1489-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 09/14/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND The induction of CD80 on podocytes has been shown in animal models of podocyte injury and in certain cases of nephrotic syndrome. In a lipopolysaccharide (LPS)-induced mouse model of albuminuria, we have recently shown a signalling axis of LPS-myeloid cell activation-TNFα production-podocyte CD80 induction-albuminuria. Therefore, in this report, we investigated the cellular and molecular consequences of TNFα addition and CD80 expression on cultured podocytes. METHODS A murine podocyte cell line was used for TNFα treatment and for over-expressing CD80. Expression and localization of various podocyte proteins was analysed by reverse transcriptase-polymerase chain reaction, western blotting and immunofluorescence. HEK293 cells were used to biochemically characterize interactions. RESULTS Podocytes treated with LPS in vitro did not cause CD80 upregulation but TNFα treatment was associated with an increase in CD80 levels, actin derangement and poor wound healing. Podocytes stably expressing CD80 showed actin derangement and co-localization with Neph1. CD80 and Neph1 interaction was confirmed by pull down assays of CD80 and Neph1 transfected in HEK293 cells. CONCLUSION Addition of TNFα to podocytes causes CD80 upregulation, actin reorganization and podocyte injury. Overexpressed CD80 and Neph1 interact via their extracellular domain. This interaction implies a mechanism of slit diaphragm disruption and possible use of small molecules that disrupt CD80-Neph1 interaction as a potential for treatment of nephrotic syndrome associated with CD80 upregulation.
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108
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Abstract
This chapter offers a brief introduction of the functions of TRPC channels in non-neuronal systems. We focus on three major organs of which the research on TRPC channels have been most focused on: kidney, heart, and lung. The chapter highlights on cellular functions and signaling pathways mediated by TRPC channels. It also summarizes several inherited diseases in humans that are related to or caused by TRPC channel mutations and malfunction. A better understanding of TRPC channels functions and the importance of TRPC channels in health and disease should lead to new insights and discovery of new therapeutic approaches for intractable disease.
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109
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Hagmann H, Mangold N, Rinschen MM, Koenig T, Kunzelmann K, Schermer B, Benzing T, Brinkkoetter PT. Proline-dependent and basophilic kinases phosphorylate human TRPC6 at serine 14 to control channel activity through increased membrane expression. FASEB J 2017; 32:208-219. [PMID: 28877958 DOI: 10.1096/fj.201700309r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 08/21/2017] [Indexed: 01/01/2023]
Abstract
Signaling via the transient receptor potential (TRP) ion channel C6 plays a pivotal role in hereditary and sporadic glomerular kidney disease. Several studies have identified gain-of-function mutations of TRPC6 and report induced expression and enhanced channel activity of TRPC6 in association with glomerular diseases. Interfering with TRPC6 activity may open novel therapeutic pathways. TRPC6 channel activity is controlled by protein expression and stability as well as intracellular trafficking. Identification of regulatory phosphorylation sites in TRPC6 and corresponding protein kinases is essential to understand the regulation of TRPC6 activity and may result in future therapeutic strategies. In this study, an unbiased phosphoproteomic screen of human TRPC6 identified several novel serine phosphorylation sites. The phosphorylation site at serine 14 of TRPC6 is embedded in a basophilic kinase motif that is highly conserved across species. We confirmed serine 14 as a target of MAPKs and proline-directed kinases like cyclin-dependent kinase 5 (Cdk5) in cell-based as well as in vitro kinase assays and quantitative phosphoproteomic analysis of TRPC6. Phosphorylation of TRPC6 at serine 14 enhances channel conductance by boosting membrane expression of TRPC6, whereas protein stability and multimerization of TRPC6 are not altered, making serine 14 phosphorylation a potential drug target to interfere with TRPC6 channel activity.-Hagmann, H., Mangold, N., Rinschen, M. M., Koenig, T., Kunzelmann, K., Schermer, B., Benzing, T., Brinkkoetter, P. T. Proline-dependent and basophilic kinases phosphorylate human TRPC6 at serine 14 to control channel activity through increased membrane expression.
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Affiliation(s)
- Henning Hagmann
- Department II of Internal Medicine, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Nicole Mangold
- Department II of Internal Medicine, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department II of Internal Medicine, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Tim Koenig
- Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Institute for Genetics Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; and
| | - Karl Kunzelmann
- Department of Physiology, University Regensburg, Regensburg, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Response in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Paul T Brinkkoetter
- Department II of Internal Medicine, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany;
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110
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Schlöndorff D, Wyatt CM, Campbell KN. Revisiting the determinants of the glomerular filtration barrier: what goes round must come round. Kidney Int 2017; 92:533-536. [DOI: 10.1016/j.kint.2017.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 06/01/2017] [Indexed: 11/25/2022]
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111
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Song K, Fu J, Song J, Herzog BH, Bergstrom K, Kondo Y, McDaniel JM, McGee S, Silasi-Mansat R, Lupu F, Chen H, Bagavant H, Xia L. Loss of mucin-type O-glycans impairs the integrity of the glomerular filtration barrier in the mouse kidney. J Biol Chem 2017; 292:16491-16497. [PMID: 28842487 DOI: 10.1074/jbc.m117.798512] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/14/2017] [Indexed: 12/14/2022] Open
Abstract
The kidney's filtration activity is essential for removing toxins and waste products from the body. The vascular endothelial cells of the glomerulus are fenestrated, flattened, and surrounded by podocytes, specialized cells that support glomerular endothelial cells. Mucin-type core 1-derived O-glycans (O-glycans) are highly expressed on both glomerular capillary endothelial cells and their supporting podocytes, but their biological role is unclear. Biosynthesis of core 1-derived O-glycans is catalyzed by the glycosyltransferase core 1 β1,3-galactosyltransferase (C1galt1). Here we report that neonatal or adult mice with inducible deletion of C1galt1 (iC1galt1-/-) exhibit spontaneous proteinuria and rapidly progressing glomerulosclerosis. Ultrastructural analysis of the glomerular filtration barrier components revealed that loss of O-glycans results in altered podocyte foot processes. Further analysis indicated that O-glycan is essential for the normal signaling function of podocalyxin, a podocyte foot process-associated glycoprotein. Our results reveal a new function of O-glycosylation in the integrity of the glomerular filtration barrier.
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Affiliation(s)
- Kai Song
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104.,the Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Jianxin Fu
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Jianhua Song
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Brett H Herzog
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Kirk Bergstrom
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Yuji Kondo
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - J Michael McDaniel
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Samuel McGee
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Robert Silasi-Mansat
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Florea Lupu
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Hong Chen
- the Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Harini Bagavant
- the Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104
| | - Lijun Xia
- From the Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, .,the Jiangsu Institute of Hematology, Collaborative Innovation Center of Hematology, Key Laboratory of Thrombosis and Hemostasis of Ministry of Health, First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu, China, and.,the Department of Molecular Biology and Biochemistry, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104
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112
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Wadie W, El-Tanbouly DM. Vinpocetine mitigates proteinuria and podocytes injury in a rat model of diabetic nephropathy. Eur J Pharmacol 2017; 814:187-195. [PMID: 28843828 DOI: 10.1016/j.ejphar.2017.08.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 08/12/2017] [Accepted: 08/23/2017] [Indexed: 11/30/2022]
Abstract
Podocyte injury and glomerular basement membrane thickening have been considered as essential pathophysiological events in diabetic nephropathy. The aim of this study was to investigate the possible beneficial effects of vinpocetine on diabetes-associated renal damage. Male Wistar rats were made diabetic by injection of streptozotocin (STZ). Diabetic rats were treated with vinpocetine in a dose of 20mg/kg/day for 6 weeks. Treatment with vinpocetine resulted in a marked decrease in the levels of blood glucose, glycosylated haemoglobin, creatinine, blood urea nitrogen, urinary albumin and albumin/creatinine ratio along with an elevation in creatinine clearance rate. The renal contents of advanced glycation end-products, interleukin-10, tissue growth factor-β, nuclear factor (NF)-κB and Ras-related C3 botulinum toxin substrate 1 (Rac 1) were decreased. Renal nephrin and podocin contents were increased and their mRNA expressions were replenished in vinpocetine-treated rats. Moreover, administration of vinpocetine showed improvements in oxidative status as well as renal glomerular and tubular structures. The current investigation revealed that vinpocetine ameliorated the STZ-induced renal damage. This beneficial effect could be attributed to its antioxidant and antihyperglycemic effects parallel to its ability to inhibit NF-κB which eventually modulated cytokines production as well as nephrin and podocin proteins expression.
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Affiliation(s)
- Walaa Wadie
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Dalia M El-Tanbouly
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
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113
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114
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Kang MK, Park SH, Kim YH, Lee EJ, Antika LD, Kim DY, Choi YJ, Kang YH. Chrysin ameliorates podocyte injury and slit diaphragm protein loss via inhibition of the PERK-eIF2α-ATF-CHOP pathway in diabetic mice. Acta Pharmacol Sin 2017; 38:1129-1140. [PMID: 28502979 DOI: 10.1038/aps.2017.30] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 02/20/2017] [Indexed: 12/17/2022] Open
Abstract
Glomerular epithelial podocytes are highly specialized cells that play a crucial role in maintaining normal function of the glomerular filtration barrier via their foot processes. Chrysin (5,7-dihydroxyflavone) is a natural flavonoid found in propolis and mushrooms that has anti-inflammatory, antioxidant and anticancer properties. This study aimed to evaluate the renoprotective effects of chrysin on podocyte apoptotic loss and slit diaphragm protein deficiency in high glucose-exposed podocytes and in db/db mouse kidneys. Exposure to high glucose (33 mmol/L) caused glomerular podocyte apoptosis in vitro, which was dose-dependently attenuated by nontoxic chrysin (1-20 μmol/L) through reduction of DNA fragmentation. Chrysin treatment dose-dependently restored the increased Bax/Bcl-2 ratio, and suppressed Apaf-1 induction and the elevated cytochrome c release in high glucose-exposed renal podocytes. In diabetic db/db mice, oral administration of chrysin (10 mg·kg-1·d-1, for 10 weeks) significantly attenuated proteinuria, and alleviated the abnormal alterations in glomerular ultrastructure, characterized by apoptotic podocytes and foot process effacement. In addition, this compound improved the induction of slit diaphragm proteins podocin/nephrin in the diabetic glomeruli. Exposure to high glucose elevated the unfolded protein response (UPR) to ER stress in renal podocytes, evidenced by up-regulation of PERK-eIF2α-ATF4-CHOP. Chrysin treatment blocked such ER stress responses pertinent to podocyte apoptosis and reduced synthesis of slit diaphragm proteins in vitro and in vivo. These observations demonstrate that targeting ER stress is an underlying mechanism of chrysin-mediated amelioration of diabetes-associated podocyte injury and dysfunction.
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115
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Rinschen MM, Hoppe AK, Grahammer F, Kann M, Völker LA, Schurek EM, Binz J, Höhne M, Demir F, Malisic M, Huber TB, Kurschat C, Kizhakkedathu JN, Schermer B, Huesgen PF, Benzing T. N-Degradomic Analysis Reveals a Proteolytic Network Processing the Podocyte Cytoskeleton. J Am Soc Nephrol 2017; 28:2867-2878. [PMID: 28724775 DOI: 10.1681/asn.2016101119] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 05/08/2017] [Indexed: 11/03/2022] Open
Abstract
Regulated intracellular proteostasis, controlled in part by proteolysis, is essential in maintaining the integrity of podocytes and the glomerular filtration barrier of the kidney. We applied a novel proteomics technology that enables proteome-wide identification, mapping, and quantification of protein N-termini to comprehensively characterize cleaved podocyte proteins in the glomerulus in vivo We found evidence that defined proteolytic cleavage results in various proteoforms of important podocyte proteins, including those of podocin, nephrin, neph1, α-actinin-4, and vimentin. Quantitative mapping of N-termini demonstrated perturbation of protease action during podocyte injury in vitro, including diminished proteolysis of α-actinin-4. Differentially regulated protease substrates comprised cytoskeletal proteins as well as intermediate filaments. Determination of preferential protease motifs during podocyte damage indicated activation of caspase proteases and inhibition of arginine-specific proteases. Several proteolytic processes were clearly site-specific, were conserved across species, and could be confirmed by differential migration behavior of protein fragments in gel electrophoresis. Some of the proteolytic changes discovered in vitro also occurred in two in vivo models of podocyte damage (WT1 heterozygous knockout mice and puromycin aminonucleoside-treated rats). Thus, we provide direct and systems-level evidence that the slit diaphragm and podocyte cytoskeleton are regulated targets of proteolytic modification, which is altered upon podocyte damage.
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Affiliation(s)
- Markus M Rinschen
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC).,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), and.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Ann-Kathrin Hoppe
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC)
| | - Florian Grahammer
- Department of Medicine III, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Medicine IV, Medical Center and Faculty of Medicine - University of Freiburg, Freiburg, Germany
| | - Martin Kann
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC)
| | - Linus A Völker
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC)
| | - Eva-Maria Schurek
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC)
| | - Julie Binz
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC)
| | - Martin Höhne
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC).,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), and.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Fatih Demir
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany
| | - Milena Malisic
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany
| | - Tobias B Huber
- Department of Medicine III, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Medicine IV, Medical Center and Faculty of Medicine - University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies and Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University, Freiburg, Germany; and
| | - Christine Kurschat
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC)
| | - Jayachandran N Kizhakkedathu
- Centre for Blood Research, Department of Pathology and Laboratory Medicine, Department of Chemistry, University of British Columbia, Vancouver, Canada
| | - Bernhard Schermer
- Department II of Internal Medicine.,Center for Molecular Medicine Cologne (CMMC).,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), and.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Pitter F Huesgen
- Central Institute for Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany;
| | - Thomas Benzing
- Department II of Internal Medicine, .,Center for Molecular Medicine Cologne (CMMC).,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), and.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
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116
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Kaufman DR, Papillon J, Larose L, Iwawaki T, Cybulsky AV. Deletion of inositol-requiring enzyme-1α in podocytes disrupts glomerular capillary integrity and autophagy. Mol Biol Cell 2017; 28:1636-1651. [PMID: 28428258 PMCID: PMC5469607 DOI: 10.1091/mbc.e16-12-0828] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/10/2017] [Accepted: 04/14/2017] [Indexed: 12/02/2022] Open
Abstract
Inositol-requiring enzyme-1α (IRE1α) is an endoplasmic reticulum (ER)-transmembrane endoribonuclease kinase that plays an essential function in extraembryonic tissues during normal development and is activated during ER stress. To address the functional role of IRE1α in glomerular podocytes, we produced podocyte-specific IRE1α-deletion mice. In male mice, deletion of IRE1α in podocytes resulted in albuminuria beginning at 5 mo of age and worsening with time. Electron microscopy revealed focal podocyte foot-process effacement in 9-mo-old male IRE1α-deletion mice, as well as microvillous transformation of podocyte plasma membranes. Compared with control, glomerular cross-sectional and capillary lumenal areas were greater in deletion mice, and there was relative podocyte depletion. Levels of microtubule-associated protein 1A/1B-light chain 3 (LC3)-II expression and c-Jun N-terminal kinase-1 phosphorylation were decreased in IRE1α-deletion glomeruli, in keeping with reduced autophagy. Deletion of IRE1α exacerbated glomerular injury in anti-glomerular basement membrane nephritis. In cell culture, IRE1α dominant-negative mutants reduced the physiological (basal) accumulation of LC3B-II and the size of autophagic vacuoles but did not affect ER-associated degradation. Thus IRE1α is essential for maintaining podocyte and glomerular integrity as mice age and in glomerulonephritis. The mechanism is related, at least in part, to the maintenance of autophagy in podocytes.
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Affiliation(s)
- Daniel Robert Kaufman
- Department of Physiology, McGill University, and McGill University Health Centre Research Institute, Montreal, QC H4A 3J1, Canada
| | - Joan Papillon
- Department of Medicine, McGill University, and McGill University Health Centre Research Institute, Montreal, QC H4A 3J1, Canada
| | - Louise Larose
- Department of Medicine, McGill University, and McGill University Health Centre Research Institute, Montreal, QC H4A 3J1, Canada
| | - Takao Iwawaki
- Department of Life Science, Medical Research Institute, Kanazawa Medical University, Uchinada 920-0293, Japan
| | - Andrey V Cybulsky
- Department of Physiology, McGill University, and McGill University Health Centre Research Institute, Montreal, QC H4A 3J1, Canada
- Department of Medicine, McGill University, and McGill University Health Centre Research Institute, Montreal, QC H4A 3J1, Canada
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117
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Dab1 Contributes to Angiotensin II-Induced Apoptosis via p38 Signaling Pathway in Podocytes. BIOMED RESEARCH INTERNATIONAL 2017; 2017:2484303. [PMID: 28676854 PMCID: PMC5476836 DOI: 10.1155/2017/2484303] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 04/16/2017] [Accepted: 05/10/2017] [Indexed: 12/24/2022]
Abstract
Numerous studies have found that angiotensin II (Ang II) participates in podocyte apoptosis and exacerbates progression of end-stage kidney disease (ESKD). However, its underlying mechanism remains largely unexplored. As a homolog of Drosophila disabled (Dab) protein, Dab1 plays a vital role in cytoskeleton, neuronal migration, and proliferation. In the present study, our data revealed that Ang II-infused rats developed hypertension, proteinuria, and podocyte injury accompanied by Dab1 phosphorylation and increased reelin expression in kidney. Moreover, Ang II induced podocyte apoptosis in vitro. Dab1 phosphorylation and reelin expression in podocytes were increased after exposure to Ang II. Conversely, Dab1 small interfering RNA (siRNA) exerted protective effects on Ang II-induced podocyte apoptosis, resulting in decreased p38 phosphorylation and reelin expression. These results indicated that Dab1 mediated Ang II-induced podocyte apoptosis via p38 signaling pathway.
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118
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Koehler S, Brähler S, Braun F, Hagmann H, Rinschen MM, Späth MR, Höhne M, Wunderlich FT, Schermer B, Benzing T, Brinkkoetter PT. Construction of a viral T2A-peptide based knock-in mouse model for enhanced Cre recombinase activity and fluorescent labeling of podocytes. Kidney Int 2017; 91:1510-1517. [PMID: 28187984 DOI: 10.1016/j.kint.2016.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/23/2016] [Accepted: 12/01/2016] [Indexed: 12/16/2022]
Abstract
Podocyte injury is a key event in glomerular disease leading to proteinuria and opening the path toward glomerular scarring. As a consequence, glomerular research strives to discover molecular mechanisms and signaling pathways affecting podocyte health. The hNphs2.Cre mouse model has been a valuable tool to manipulate podocyte-specific genes and to label podocytes for lineage tracing and purification. Here we designed a novel podocyte-specific tricistronic Cre mouse model combining codon improved Cre expression and fluorescent cell labeling with mTomato under the control of the endogenous Nphs2 promoter using viral T2A-peptides. Independent expression of endogenous podocin, codon improved Cre, and mTomato was confirmed by immunofluorescence, fluorescent activated cell sorting and protein analyses. Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type mice developed normally and did not show any signs of glomerular disease or off-target effects under basal conditions and in states of disease. Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type-mediated gene recombination was superior to conventional hNphs2.Cre mice-mediated gene recombination. Last, we compared Cre efficiency in a disease model by mating Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type and hNphs2.Cre mice to Phb2fl/fl mice. The podocyte-specific Phb2 knockout by Nphs2pod.T2A.ciCre.T2A.mTomato/wild-type mice resulted in an aggravated glomerular injury as compared to a podocyte-specific Phb2 gene deletion triggered by hNphs2.Cre. Thus, we generated the first tricistronic podocyte mouse model combining enhanced Cre recombinase efficiency and fluorescent labeling in podocytes without the need for additional matings with conventional reporter mouse lines.
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Affiliation(s)
- Sybille Koehler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sebastian Brähler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Department of Pathology and Immunology, Division of Immunobiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Fabian Braun
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Henning Hagmann
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Martin R Späth
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Martin Höhne
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | | | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Paul T Brinkkoetter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.
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119
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Cybulsky AV, Guillemette J, Papillon J, Abouelazm NT. Regulation of Ste20-like kinase, SLK, activity: Dimerization and activation segment phosphorylation. PLoS One 2017; 12:e0177226. [PMID: 28475647 PMCID: PMC5419656 DOI: 10.1371/journal.pone.0177226] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/24/2017] [Indexed: 12/11/2022] Open
Abstract
The Ste20-like kinase, SLK, has diverse cellular functions. SLK mediates organ development, cell cycle progression, cytoskeletal remodeling, cytokinesis, and cell survival. Expression and activity of SLK are enhanced in renal ischemia-reperfusion injury, and overexpression of SLK was shown to induce apoptosis in cultured glomerular epithelial cells (GECs) and renal tubular cells, as well as GEC/podocyte injury in vivo. The SLK protein consists of a N-terminal catalytic domain and an extensive C-terminal domain, which contains coiled-coils. The present study addresses the regulation of SLK activity. Controlled dimerization of the SLK catalytic domain enhanced autophosphorylation of SLK at T183 and S189, which are located in the activation segment. The full-length ectopically- and endogenously-expressed SLK was also autophosphorylated at T183 and S189. Using ezrin as a model SLK substrate (to address exogenous kinase activity), we demonstrate that dimerized SLK 1–373 or full-length SLK can effectively induce activation-specific phosphorylation of ezrin. Mutations in SLK, including T183A, S189A or T193A reduced T183 or S189 autophosphorylation, and showed a greater reduction in ezrin phosphorylation. Mutations in the coiled-coil region of full-length SLK that impair dimerization, in particular I848G, significantly reduced ezrin phosphorylation and tended to reduce autophosphorylation of SLK at T183. In experimental membranous nephropathy in rats, proteinuria and GEC/podocyte injury were associated with increased glomerular SLK activity and ezrin phosphorylation. In conclusion, dimerization via coiled-coils and phosphorylation of T183, S189 and T193 play key roles in the activation and signaling of SLK, and provide targets for novel therapeutic approaches.
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Affiliation(s)
- Andrey V. Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
- * E-mail:
| | - Julie Guillemette
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Joan Papillon
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
| | - Nihad T. Abouelazm
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, Quebec, Canada
- Department of Clinical Pharmacology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
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120
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Zhai L, Gu J, Yang D, Hu W, Wang W, Ye S. Metformin ameliorates podocyte damage by restoring renal tissue nephrin expression in type 2 diabetic rats. J Diabetes 2017; 9:510-517. [PMID: 27248136 DOI: 10.1111/1753-0407.12437] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 05/14/2016] [Accepted: 05/26/2016] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Previous studies found that metformin provided some renoprotection for diabetic renal damage. In the present study, we evaluated the effects of different doses of metformin on the expression of renal tissue nephrin in type 2 diabetes mellitus (T2DM) model rats and the possible mechanism underlying its protective effect in kidney podocytes. METHODS A high-fat diet combined with a low dose of streptozotocin was used to induce T2DM model rats. Diabetic rats were treated with 150, 300, or 500 mg/kg metformin for 8 weeks. At the end of the study, urine and blood samples were collected for measurement of different indices. Light microscopy and transmission electron microscopy were used to identify morphological changes. Renal expression of nephrin protein was assayed by immunohistochemical staining, whereas real-time polymerase chain reaction was used to detect renal nephrin (Nphs1) mRNA expression. RESULTS Metformin treatment of T2DM rats produced dose-dependent significant reductions in urinary albumin and nephrin concentrations, glomerular basement membrane thickness (GBMT), and the foot process fusion rate (FPFR) compared with control T2DM model rats, whereas renal expression of nephrin protein and Nphs1 mRNA was dose-dependently increased by metformin treatment. CONCLUSION Metformin protects kidney podocytes in T2DM model rats by dose-dependently adjusting renal nephrin expression.
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MESH Headings
- Albuminuria/urine
- Animals
- Blood Glucose/analysis
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/genetics
- Diet, High-Fat/adverse effects
- Dose-Response Relationship, Drug
- Gene Expression/drug effects
- Glycated Hemoglobin/analysis
- Hypoglycemic Agents/pharmacology
- Immunohistochemistry
- Insulin/blood
- Kidney/drug effects
- Kidney/metabolism
- Kidney/ultrastructure
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Membrane Proteins/urine
- Metformin/pharmacology
- Microscopy, Electron, Transmission
- Podocytes/drug effects
- Podocytes/metabolism
- Podocytes/pathology
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Limin Zhai
- Department of Endocrinology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, China
| | - Junfei Gu
- Department of Endocrinology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, China
| | - Di Yang
- Department of Endocrinology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, China
| | - Wen Hu
- Department of Pathology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, China
| | - Wei Wang
- Department of Endocrinology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, China
| | - Shandong Ye
- Department of Endocrinology, Anhui Provincial Hospital Affiliated to Anhui Medical University, Hefei, China
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121
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Rinschen MM, Grahammer F, Hoppe AK, Kohli P, Hagmann H, Kretz O, Bertsch S, Höhne M, Göbel H, Bartram MP, Gandhirajan RK, Krüger M, Brinkkoetter PT, Huber TB, Kann M, Wickström SA, Benzing T, Schermer B. YAP-mediated mechanotransduction determines the podocyte's response to damage. Sci Signal 2017; 10:10/474/eaaf8165. [PMID: 28400537 DOI: 10.1126/scisignal.aaf8165] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Podocytes are terminally differentiated cells of the kidney filtration barrier. They are subjected to physiological filtration pressure and considerable mechanical strain, which can be further increased in various kidney diseases. When injury causes cytoskeletal reorganization and morphological alterations of these cells, the filtration barrier may become compromised and allow proteins to leak into the urine (a condition called proteinuria). Using time-resolved proteomics, we showed that podocyte injury stimulated the activity of the transcriptional coactivator YAP and the expression of YAP target genes in a rat model of glomerular disease before the development of proteinuria. Although the activities of YAP and its ortholog TAZ are activated by mechanical stress in most cell types, injury reduced YAP and TAZ activity in cultured human and mouse podocyte cell lines grown on stiff substrates. Culturing these cells on soft matrix or inhibiting stress fiber formation recapitulated the damage-induced YAP up-regulation observed in vivo, indicating a mechanotransduction-dependent mechanism of YAP activation in podocytes. YAP overexpression in cultured podocytes increased the abundance of extracellular matrix-related proteins that can contribute to fibrosis. YAP activity was increased in mouse models of diabetic nephropathy, and the YAP target CTGF was highly expressed in renal biopsies from glomerular disease patients. Although overexpression of human YAP in mice induced mild proteinuria, pharmacological inhibition of the interaction between YAP and its partner TEAD in rats ameliorated glomerular disease and reduced damage-induced mechanosignaling in the glomeruli. Thus, perturbation of YAP-dependent mechanosignaling is a potential therapeutic target for treating some glomerular diseases.
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Affiliation(s)
- Markus M Rinschen
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Florian Grahammer
- Department of Medicine IV, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany.,III. Medical Clinic and Polyclinic, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ann-Kathrin Hoppe
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Priyanka Kohli
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Cologne, Germany
| | - Henning Hagmann
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Oliver Kretz
- Department of Medicine IV, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany.,III. Medical Clinic and Polyclinic, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Neuroanatomy, Institute of Anatomy, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sabine Bertsch
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Martin Höhne
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Heike Göbel
- Institute of Pathology, University of Cologne, Cologne, Germany
| | - Malte P Bartram
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | | | - Marcus Krüger
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Cologne, Germany
| | - Paul-Thomas Brinkkoetter
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Tobias B Huber
- Department of Medicine IV, Medical Center and Faculty of Medicine, University of Freiburg, Freiburg, Germany.,III. Medical Clinic and Polyclinic, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Center for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Martin Kann
- Department of Internal Medicine II, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sara A Wickström
- Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Cologne, Germany.,Skin Homeostasis and Ageing, Paul Gerson Unna Research Group, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Thomas Benzing
- Department of Internal Medicine II, University of Cologne, Cologne, Germany. .,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Bernhard Schermer
- Department of Internal Medicine II, University of Cologne, Cologne, Germany. .,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Cluster of Excellence in Cellular Stress Responses in Aging-associated Diseases, University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
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122
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Ilatovskaya DV, Palygin O, Levchenko V, Endres BT, Staruschenko A. The Role of Angiotensin II in Glomerular Volume Dynamics and Podocyte Calcium Handling. Sci Rep 2017; 7:299. [PMID: 28331185 PMCID: PMC5428415 DOI: 10.1038/s41598-017-00406-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 02/27/2017] [Indexed: 02/03/2023] Open
Abstract
Podocytes are becoming a primary focus of research efforts due to their association with progressive glomeruli damage in disease states. Loss of podocytes can occur as a result of excessive intracellular calcium influx, and we have previously shown that angiotensin II (Ang II) via canonical transient receptor potential 6 (TRPC6) channels caused increased intracellular Ca2+ flux in podocytes. We showed here with patch-clamp electrophysiology that Ang II activates TRPC channels; then using confocal calcium imaging we demonstrated that Ang II-dependent stimulation of Ca2+ influx in the podocytes is precluded by blocking either AT1 or AT2 receptors (ATRs). Application of Ang(1-7) had no effect on intracellular calcium. Ang II-induced calcium flux was decreased upon inhibition of TRPC channels with SAR7334, SKF 96365, clemizole hydrochloride and La3+, but not ML204. Using a novel 3D whole-glomerulus imaging ex vivo assay, we revealed the involvement of both ATRs in controlling glomerular permeability; additionally, using specific inhibitors and activators of TRPC6, we showed that these channels are implicated in the regulation of glomerular volume dynamics. Therefore, we provide evidence demonstrating the critical role of Ang II/TRPC6 axis in the control of glomeruli function, which is likely important for the development of glomerular diseases.
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Affiliation(s)
- Daria V Ilatovskaya
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226, USA
| | - Vladislav Levchenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226, USA
| | - Bradley T Endres
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226, USA
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, 53226, USA.
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123
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Autophagy Protects against Palmitic Acid-Induced Apoptosis in Podocytes in vitro. Sci Rep 2017; 7:42764. [PMID: 28225005 PMCID: PMC5320537 DOI: 10.1038/srep42764] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/13/2017] [Indexed: 01/01/2023] Open
Abstract
Autophagy is a highly conserved degradation process that is involved in the clearance of proteins and damaged organelles to maintain intracellular homeostasis and cell integrity. Type 2 diabetes is often accompanied by dyslipidemia with elevated levels of free fatty acids (FFAs). Podocytes, as an important component of the filtration barrier, are susceptible to lipid disorders. The loss of podocytes causes proteinuria, which is involved in the pathogenesis of diabetic nephropathy. In the present study, we demonstrated that palmitic acid (PA) promoted autophagy in podocytes. We further found that PA increased the production of reactive oxygen species (ROS) in podocytes and that NAC (N-acetyl-cysteine), a potent antioxidant, significantly eliminated the excessive ROS and suppressed autophagy, indicating that the increased generation of ROS was associated with the palmitic acid-induced autophagy in podocytes. Moreover, we also found that PA stimulation decreased the mitochondrial membrane potential in podocytes and induced podocyte apoptosis, while the inhibition of autophagy by chloroquine (CQ) enhanced palmitic acid-induced apoptosis accompanied by increased ROS generation, and the stimulation of autophagy by rapamycin (Rap) remarkably suppressed palmitic acid-induced ROS generation and apoptosis. Taken together, these in vitro findings suggest that PA-induced autophagy in podocytes is mediated by ROS production and that autophagy plays a protective role against PA-induced podocyte apoptosis.
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124
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Histamine type 1-receptor activation by low dose of histamine undermines human glomerular slit diaphragm integrity. Pharmacol Res 2016; 114:27-38. [DOI: 10.1016/j.phrs.2016.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 11/20/2022]
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125
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Furuta I, Zhai T, Ishikawa S, Umazume T, Nakagawa K, Yamada T, Morikawa M, Minakami H. Association between nephrinuria, podocyturia, and proteinuria in women with pre-eclampsia. J Obstet Gynaecol Res 2016; 43:34-41. [DOI: 10.1111/jog.13180] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 07/26/2016] [Accepted: 08/21/2016] [Indexed: 01/06/2023]
Affiliation(s)
- Itsuko Furuta
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
| | - Tianyue Zhai
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
| | - Satoshi Ishikawa
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
| | - Takeshi Umazume
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
| | - Kinuko Nakagawa
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
| | - Takahiro Yamada
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
| | - Mamoru Morikawa
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
| | - Hisanori Minakami
- Department of Obstetrics; Hokkaido University Graduate School of Medicine; Sapporo Hokkaido Japan
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126
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Minimal change nephrotic syndrome and prohibitin-2 gene polymorphism. Clin Exp Nephrol 2016; 21:665-670. [PMID: 27812762 DOI: 10.1007/s10157-016-1325-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/14/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Patients with minimal change nephrotic syndrome (MCNS) often also have allergic diseases. Abnormalities of Th2-derived cytokines and T-cell functions contribute to development of these diseases. On the other hand, imbalances between reactive oxygen species (ROS) and antioxidants have been implicated in MCNS and progression of atopic dermatitis. ROS, produced mainly within mitochondria, subject cells to oxidative stress, while prohibitin 2 protects mitochondria by increasing tolerance to ROS. Additionally, podocin, a member of the slit diaphragm protein complex, contains PHB-like domain that serves as a signaling platform regulating podocyte function through associated transmembrane proteins. PATIENTS AND METHOD Then, we performed exome sequencing analysis in five patients with frequently relapsing their MCNS associated with allergic disease and serum IgE concentrations of 2000 IU/L or higher. RESULTS We detected a heterozygous prohibitin 2 polymorphism, c.873-3_873-2 delCA (rs111523336), in 1 patient. This mutation in exon 9 caused frameshifts in regions connected to splicing sites, where they could disrupt transcription of prohibitin 2. Frequency of this polymorphism in exon 9 is 7.3% among Japanese. Increase in peripheral blood ROS even MCNS remission state suggests the heterozygous prohibitin 2 variant may contribute to give more susceptibility towards the recurrence of MCNS as well as atopic skin disease. This increase may have progression of atopic dermatitis, which sometimes heralded. CONCLUSION The prohibitin-2 polymorphism may reduce ROS tolerance in glomerular epithelium and led to high local exposure to ROS, increasing permeability of the glomerular basement membrane to result in proteinuria. Imbalance between ROS and antioxidants together with failure of signal transduction in the glomerular slit membrane caused by prohibitin 2 abnormality could have contributed to nephrotic syndrome in our patients. Prohibitin 2 analysis is needed in additional MCNS patients with concomitant allergic disease.
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Hu M, Fan M, Zhen J, Lin J, Wang Q, Lv Z, Wang R. FAK contributes to proteinuria in hypercholesterolaemic rats and modulates podocyte F-actin re-organization via activating p38 in response to ox-LDL. J Cell Mol Med 2016; 21:552-567. [PMID: 27704688 PMCID: PMC5323874 DOI: 10.1111/jcmm.13001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 08/29/2016] [Indexed: 11/28/2022] Open
Abstract
Focal adhesion kinase (FAK) is a non-receptor protein tyrosine kinase that regulates cell adhesion, proliferation and differentiation. In the present study, a rat model of high fat diet-induced hypercholesterolaemia was established to investigate the involvement of FAK in lipid disorder-related kidney diseases. We showed focal fusion of podocyte foot process that occurred at as early as 4 weeks in rats consuming high fat diet, preceding the onset of proteinuria when aberrant phosphorylation of FAK was found. These abnormalities were ameliorated by dietary intervention of TAE226, a reported inhibitor of FAK. FAK is also an adaptor protein initiating cascades of intracellular signals including c-Src, Rho GTPase and mitogen-activated protein kinase (MAPK). P38 MAPK belongs to the latter and is centrally involved in kidney diseases. Our cell culture data revealed oxidized low-density lipoprotein (ox-LDL) triggered hyper-phosphorylation of FAK and p38, ectopic expression of cellular markers (manifested as decreased WT1, podocin and NEPH1, and increased vimentin and mmp9), and re-arrangement of F-actin filaments with enhanced cell motility; these mutations were significantly rectified by FAK shRNA. Notably, pre-treatment of p38 inhibitor did not alter FAK activation, albeit its deletion of p38 hyper-activity and attenuation of cellular abnormalities, demonstrating that p38 acted as a downstream effector of FAK signalling and ox-LDL damaged podocytes in a FAK/p38-dependent manner. This was further identified by animal data that p38 activation was also abrogated by TAE226 treatment in hypercholesterolaemic rats, suggesting that FAK/p38 axis might also be involved in in vivo events. These findings provided a potential early mechanism of hypercholesterolaemia-related podocyte damage and proteinuria.
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Affiliation(s)
- Mengsi Hu
- Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Minghua Fan
- Department of Obstetrics and Gynecology, The Second Hospital of Shandong University, Jinan, China
| | - Junhui Zhen
- Department of Pathology, School of Medicine, Shandong University, Jinan, China
| | - Jiangong Lin
- Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Qun Wang
- Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Zhimei Lv
- Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Rong Wang
- Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China
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Loss of endogenous thymosin β 4 accelerates glomerular disease. Kidney Int 2016; 90:1056-1070. [PMID: 27575556 PMCID: PMC5073078 DOI: 10.1016/j.kint.2016.06.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 06/22/2016] [Accepted: 06/23/2016] [Indexed: 11/23/2022]
Abstract
Glomerular disease is characterized by morphologic changes in podocyte cells accompanied by inflammation and fibrosis. Thymosin β4 regulates cell morphology, inflammation, and fibrosis in several organs and administration of exogenous thymosin β4 improves animal models of unilateral ureteral obstruction and diabetic nephropathy. However, the role of endogenous thymosin β4 in the kidney is unknown. We demonstrate that thymosin β4 is expressed prominently in podocytes of developing and adult mouse glomeruli. Global loss of thymosin β4 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 β4 in nephrotoxic nephritis led to the redistribution of podocytes from the glomerular tuft toward the Bowman capsule suggesting a role for thymosin β4 in the migration of these cells. Thymosin β4 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 β4 is a modifier of glomerular injury, likely having a protective role acting as a brake to slow disease progression.
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Zhai T, Furuta I, Akaishi R, Kawabata K, Chiba K, Umazume T, Ishikawa S, Yamada T, Morikawa M, Minakami H. Feasibility of nephrinuria as a screening tool for the risk of pre-eclampsia: prospective observational study. BMJ Open 2016; 6:e011229. [PMID: 27486123 PMCID: PMC4985984 DOI: 10.1136/bmjopen-2016-011229] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVES To investigate the possibility of nephrinuria as a screening tool for the risk of pre-eclampsia (PE). DESIGN Prospective observational study. SETTING A single university hospital. Changes in urinary nephrin:creatinine ratio (NCR, ng/mg) and protein:creatinine ratio (PCR, mg/mg) in pregnancy were determined. Significant proteinuria in pregnancy (SPIP) was defined as PCR>0.27. PE was diagnosed in women with both SPIP and hypertension. PARTICIPANTS 89 pregnant women in whom neither hypertension nor SPIP was present at enrolment, providing 31, 125 and 93 random urine samples during first, second and third trimesters, respectively. RESULTS PE developed in 14 of the 89 women. NCR increased with increasing PCR in 14 women with PE (correlation coefficient, 0.862; p<0.0001). In contrast, NCR did not change significantly despite significant increases in PCR in 75 women with normotensive pregnancies defined as neither SPIP nor hypertension, indicating that there was little increase in nephrinuria over the physiological range of proteinuria in pregnancy. Relative risk of later development of PE among asymptomatic second and third trimester women with NCR (ng/mg) >122 (95th centile value for 75 women with normotensive pregnancies) was 5.93 (95% CI 2.59 to 13.6; 60% (6/10) vs 10% (8/79)) and 13.5 (95% CI 3.31 to 55.0; 75% (6/8) vs 5.5% (2/36)), respectively, compared with women with NCR≤122 at that time. CONCLUSIONS Nephrinuria was unlikely to increase in normal pregnancy. A certain NCR cut-off may efficiently differentiate women at higher risk of PE.
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Affiliation(s)
- Tianyue Zhai
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Itsuko Furuta
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Rina Akaishi
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Kosuke Kawabata
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Kentaro Chiba
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Takeshi Umazume
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Satoshi Ishikawa
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Takahiro Yamada
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Mamoru Morikawa
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
| | - Hisanori Minakami
- Department of Obstetrics, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
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Rinschen MM, Schroeter CB, Koehler S, Ising C, Schermer B, Kann M, Benzing T, Brinkkoetter PT. Quantitative deep mapping of the cultured podocyte proteome uncovers shifts in proteostatic mechanisms during differentiation. Am J Physiol Cell Physiol 2016; 311:C404-17. [PMID: 27357545 DOI: 10.1152/ajpcell.00121.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/27/2016] [Indexed: 11/22/2022]
Abstract
The renal filtration barrier is maintained by the renal podocyte, an epithelial postmitotic cell. Immortalized mouse podocyte cell lines-both in the differentiated and undifferentiated state-are widely utilized tools to estimate podocyte injury and cytoskeletal rearrangement processes in vitro. Here, we mapped the cultured podocyte proteome at a depth of more than 8,800 proteins and quantified 7,240 proteins. Copy numbers of proteins mutated in forms of hereditary nephrotic syndrome or focal segmental glomerulosclerosis (FSGS) were assessed. We found that cultured podocytes express abundant copy numbers of endogenous receptors, such as tyrosine kinase membrane receptors, the G protein-coupled receptor (GPCR), NPR3 (ANP receptor), and several poorly characterized GPCRs. The data set was correlated with deep mapping mRNA sequencing ("mRNAseq") data from the native mouse podocyte, the native mouse podocyte proteome and staining intensities from the human protein atlas. The generated data set was similar to these previously published resources, but several native and high-abundant podocyte-specific proteins were not identified in the data set. Notably, this data set detected general perturbations in proteostatic mechanisms as a dominant alteration during podocyte differentiation, with high proteasome activity in the undifferentiated state and markedly increased expression of lysosomal proteins in the differentiated state. Phosphoproteomics analysis of mouse podocytes at a resolution of more than 3,000 sites suggested a preference of phosphorylation of actin filament-associated proteins in the differentiated state. The data set obtained here provides a resource and provides the means for deep mapping of the native podocyte proteome and phosphoproteome in a similar manner.
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Affiliation(s)
- Markus M Rinschen
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; and Systems Biology of Ageing Cologne, SybaCol, Cologne, Germany
| | - Christina B Schroeter
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Sybille Koehler
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Christina Ising
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; and Systems Biology of Ageing Cologne, SybaCol, Cologne, Germany
| | - Martin Kann
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany; and Systems Biology of Ageing Cologne, SybaCol, Cologne, Germany
| | - Paul T Brinkkoetter
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany; Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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Koehler S, Tellkamp F, Niessen CM, Bloch W, Kerjaschki D, Schermer B, Benzing T, Brinkkoetter PT. Par3A is dispensable for the function of the glomerular filtration barrier of the kidney. Am J Physiol Renal Physiol 2016; 311:F112-9. [PMID: 27122542 DOI: 10.1152/ajprenal.00171.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/22/2016] [Indexed: 01/08/2023] Open
Abstract
Polarity signaling through the atypical PKC (aPKC)-Par polarity complex is essential for the development and maintenance of the podocyte architecture and the function of the glomerular filtration barrier of the kidney. To study the contribution of Par3A in this complex, we generated a novel Pard3 podocyte-specific knockout mouse model by targeting exon 6 of the Pard3 gene. Genetic deletion of Pard3a did not impair renal function, neither at birth nor later in life. Even challenging the animals did not result in glomerular disease. Despite its well-established role in aPKC-mediated signaling, Par3A appears to be dispensable for the function of the glomerular filtration barrier. Moreover, its homolog Pard3b, and not Pard3a, is the dominant Par3 gene expressed in podocytes and found at the basis of the slit diaphragm, where it partially colocalizes with podocin. In conclusion, Par3A function is either dispensable for slit diaphragm integrity, or compensatory mechanisms and a high redundancy of the different polarity proteins, including Par3B, Lgl, or PALS1, maintain the function of the glomerular filtration barrier, even in the absence of Par3A.
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Affiliation(s)
- Sybille Koehler
- Department II of Internal Medicine, University Hospital of Cologne, Cologne, Germany; Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Frederik Tellkamp
- Center for Molecular Medicine, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Department of Dermatology, University Hospital of Cologne, Cologne, Germany
| | - Carien M Niessen
- Center for Molecular Medicine, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Department of Dermatology, University Hospital of Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany, and
| | - Dontscho Kerjaschki
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Bernhard Schermer
- Department II of Internal Medicine, University Hospital of Cologne, Cologne, Germany; Center for Molecular Medicine, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University Hospital of Cologne, Cologne, Germany; Center for Molecular Medicine, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Paul T Brinkkoetter
- Department II of Internal Medicine, University Hospital of Cologne, Cologne, Germany; Center for Molecular Medicine, University of Cologne, Cologne, Germany;
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Najafian B, Tøndel C, Svarstad E, Sokolovkiy A, Smith K, Mauer M. One Year of Enzyme Replacement Therapy Reduces Globotriaosylceramide Inclusions in Podocytes in Male Adult Patients with Fabry Disease. PLoS One 2016; 11:e0152812. [PMID: 27081853 PMCID: PMC4833322 DOI: 10.1371/journal.pone.0152812] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/19/2016] [Indexed: 12/22/2022] Open
Abstract
Fabry nephropathy is associated with progressive accumulation of globotriaosylceramide (GL3) in podocytes. Reducing this GL3 burden may reduce podocyte injury. Sensitive methods to quantify podocyte GL3 content may determine whether a given strategy can benefit podocytes in Fabry disease. We developed an unbiased electron microscopic stereological method to estimate the average volume of podocytes and their GL3 inclusions in 6 paired pre- and post-enzyme replacement therapy (ERT) biopsies from 5 men with Fabry disease. Podocyte GL3 content was regularly reduced (average 73%) after 11-12 months of ERT. This was not detectable using a semi-quantitative approach. Parallel to GL3 reduction, podocytes became remarkably smaller (average 63%). These reductions in podocyte GL3 content or size were not significantly correlated with changes in foot process width (FPW). However, FPW after ERT was significantly correlated with the magnitude of the decrease in podocyte GL3 content from baseline to 11-12 months of ERT. Also podocytes exocytosed GL3 inclusions, a phenomenon correlated with their reduction in their GL3 content. Demonstrable after11-12 months, reduction in podocyte GL3 content allows for early assessment of treatment efficacy and shorter clinical trials in Fabry disease.
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Affiliation(s)
- Behzad Najafian
- Department of Pathology, University of Washington, Seattle, United States of America
- * E-mail:
| | - Camilla Tøndel
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
| | - Einar Svarstad
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Alexey Sokolovkiy
- Department of Pathology, University of Washington, Seattle, United States of America
| | - Kelly Smith
- Department of Pathology, University of Washington, Seattle, United States of America
| | - Michael Mauer
- Departments of Pediatrics and Medicine, University of Minnesota, Minneapolis, United States of America
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Kasztan M, Piwkowska A, Kreft E, Rogacka D, Audzeyenka I, Szczepanska-Konkel M, Jankowski M. Extracellular purines' action on glomerular albumin permeability in isolated rat glomeruli: insights into the pathogenesis of albuminuria. Am J Physiol Renal Physiol 2016; 311:F103-11. [PMID: 27076649 DOI: 10.1152/ajprenal.00567.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 04/12/2016] [Indexed: 12/20/2022] Open
Abstract
Purinoceptors (adrengeric receptors and P2 receptors) are expressed on the cellular components of the glomerular filtration barrier, and their activation may affect glomerular permeability to albumin, which may ultimately lead to albuminuria, a well-established risk factor for the progression of chronic kidney disease and development of cardiovascular diseases. We investigated the mechanisms underlying the in vitro and in vivo purinergic actions on glomerular filter permeability to albumin by measuring convectional albumin permeability (Palb) in a single isolated rat glomerulus based on the video microscopy method. Primary cultured rat podocytes were used for the analysis of Palb, cGMP accumulation, PKG-Iα dimerization, and immunofluorescence. In vitro, natural nucleotides (ATP, ADP, UTP, and UDP) and nonmetabolized ATP analogs (2-meSATP and ATP-γ-S) increased Palb in a time- and concentration-dependent manner. The effects were dependent on P2 receptor activation, nitric oxide synthase, and cytoplasmic guanylate cyclase. ATP analogs significantly increased Palb, cGMP accumulation, and subcortical actin reorganization in a PKG-dependent but nondimer-mediated route in cultured podocytes. In vivo, 2-meSATP and ATP-γ-S increased Palb but did not significantly affect urinary albumin excretion. Both agonists enhanced the clathrin-mediated endocytosis of albumin in podocytes. A product of adenine nucleotides hydrolysis, adenosine, increased the permeability of the glomerular barrier via adrenergic receptors in a dependent and independent manner. Our results suggest that the extracellular nucleotides that stimulate an increase of glomerular Palb involve nitric oxide synthase and cytoplasmic guanylate cyclase with actin reorganization in podocytes.
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Affiliation(s)
- Małgorzata Kasztan
- Department of Therapy Monitoring and Pharmacogenetics, Medical University of Gdansk, Gdansk, Poland
| | - Agnieszka Piwkowska
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
| | - Ewelina Kreft
- Department of Therapy Monitoring and Pharmacogenetics, Medical University of Gdansk, Gdansk, Poland
| | - Dorota Rogacka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
| | - Irena Audzeyenka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
| | | | - Maciej Jankowski
- Department of Clinical Chemistry, Medical University of Gdansk, Gdansk, Poland; and Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre Polish Academy of Sciences, Gdansk, Poland
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Weiss S, Rosendahl A, Czesla D, Meyer-Schwesinger C, Stahl RAK, Ehmke H, Kurts C, Zipfel PF, Köhl J, Wenzel UO. The complement receptor C5aR1 contributes to renal damage but protects the heart in angiotensin II-induced hypertension. Am J Physiol Renal Physiol 2016; 310:F1356-65. [PMID: 27053686 DOI: 10.1152/ajprenal.00040.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/03/2016] [Indexed: 01/04/2023] Open
Abstract
Adaptive and innate immune responses contribute to hypertension and hypertensive end-organ damage. Here, we determined the role of anaphylatoxin C5a, a major inflammatory effector of the innate immune system that is generated in response to complement activation, in hypertensive end-organ damage. For this purpose, we assessed the phenotype of C5a receptor 1 (C5aR1)-deficient mice in ANG II-induced renal and cardiac injury. Expression of C5aR1 on infiltrating and resident renal as well as cardiac cells was determined using a green fluorescent protein (GFP)-C5aR1 reporter knockin mouse. Flow cytometric analysis of leukocytes isolated from the kidney of GFP-C5aR1 reporter mice showed that 28% of CD45-positive cells expressed C5aR1. Dendritic cells were identified as the major C5aR1-expressing population (88.5%) followed by macrophages and neutrophils. Using confocal microscopy, we detected C5aR1 in the kidney mainly on infiltrating cells. In the heart, only infiltrating cells stained C5aR1 positive. To evaluate the role of C5aR1 deficiency in hypertensive injury, an aggravated model of hypertension was used. Unilateral nephrectomy was performed followed by infusion of ANG II (1.5 ng·g(-1)·min(-1)) and salt in wild-type (n = 34) and C5aR1-deficient mice (n = 32). C5aR1-deficient mice exhibited less renal injury, as evidenced by significantly reduced albuminuria. In contrast, cardiac injury was accelerated with significantly increased cardiac fibrosis and heart weight in C5aR1-deficient mice after ANG II infusion. No effect was found on blood pressure. In summary, the C5a:C5aR1 axis drives end-organ damage in the kidney but protects from the development of cardiac fibrosis and hypertrophy in experimental ANG II-induced hypertension.
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Affiliation(s)
- Sebastian Weiss
- Department of Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Alva Rosendahl
- Department of Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Daniel Czesla
- Department of Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | | | - Rolf A K Stahl
- Department of Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Heimo Ehmke
- Department of Cellular and Integrative Physiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Kurts
- Institutes of Molecular Medicine and Experimental Immunology, Rheinische Friedrich-Wilhelms University, Bonn, Germany
| | - Peter F Zipfel
- Leibniz Institute for Infection Biology, Hans-Knöll-Institute and Friedrich Schiller University, Jena, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, Lübeck, Germany, and Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Ulrich O Wenzel
- Department of Medicine, University Hospital Hamburg-Eppendorf, Hamburg, Germany;
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Progress and controversies in unraveling the glomerular filtration mechanism. Curr Opin Nephrol Hypertens 2016; 24:208-16. [PMID: 25887902 DOI: 10.1097/mnh.0000000000000116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW 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. RECENT FINDINGS 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. SUMMARY 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.
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Abou Msallem J, Chalhoub H, Al-Hariri M, Saad L, Jaffa MA, Ziyadeh FN, Jaffa AA. Mechanisms of bradykinin-induced expression of connective tissue growth factor and nephrin in podocytes. Am J Physiol Renal Physiol 2015; 309:F980-90. [PMID: 26447218 DOI: 10.1152/ajprenal.00233.2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/29/2015] [Indexed: 12/24/2022] Open
Abstract
Diabetic nephropathy (DN) is the main cause of morbidity and mortality in diabetes and is characterized by mesangial matrix deposition and podocytopathy, including podocyte loss. The risk factors and mechanisms involved in the pathogenesis of DN are still not completely defined. In the present study, we aimed to understand the cellular mechanisms through which activation of B2 kinin receptors contribute to the initiation and progression of DN. Stimulation of cultured rat podocytes with bradykinin (BK) resulted in a significant increase in ROS generation, and this was associated with a significant increase in NADPH oxidase (NOX)1 and NOX4 protein and mRNA levels. BK stimulation also resulted in a signicant increase in the phosphorylation of ERK1/2 and Akt, and this effect was inhibited in the presence of NOX1 and Nox4 small interfering (si)RNA. Furthermore, podocytes stimulated with BK resulted in a significant increase in protein and mRNA levels of connective tissue growth factor (CTGF) and, at the same time, a significant decrease in protein and mRNA levels of nephrin. siRNA targeted against NOX1 and NOX4 significantly inhibited the BK-induced increase in CTGF. Nephrin expression was increased in response to BK in the presence of NOX1 and NOX4 siRNA, thus implicating a role for NOXs in modulating the BK response in podocytes. Moreover, nephrin expression in response to BK was also significantly increased in the presence of siRNA targeted against CTGF. These findings provide novel aspects of BK signal transduction pathways in pathogenesis of DN and identify novel targets for interventional strategies.
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Affiliation(s)
- J Abou Msallem
- Biochemistry and Molecular Genetics Department, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - H Chalhoub
- Biochemistry and Molecular Genetics Department, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - M Al-Hariri
- Biochemistry and Molecular Genetics Department, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - L Saad
- Biochemistry and Molecular Genetics Department, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - M A Jaffa
- Epidemiology and Population Health Department, Faculty of Health Sciences, American University of Beirut, Beirut, Lebanon; and
| | - F N Ziyadeh
- Biochemistry and Molecular Genetics Department, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - A A Jaffa
- Biochemistry and Molecular Genetics Department, Faculty of Medicine, American University of Beirut, Beirut, Lebanon; Department of Medicine, Medical University of South Carolina, Charleston, South Carolina
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137
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Xu S, Nam SM, Kim JH, Das R, Choi SK, Nguyen TT, Quan X, Choi SJ, Chung CH, Lee EY, Lee IK, Wiederkehr A, Wollheim CB, Cha SK, Park KS. Palmitate induces ER calcium depletion and apoptosis in mouse podocytes subsequent to mitochondrial oxidative stress. Cell Death Dis 2015; 6:e1976. [PMID: 26583319 PMCID: PMC4670935 DOI: 10.1038/cddis.2015.331] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 10/02/2015] [Accepted: 10/12/2015] [Indexed: 12/14/2022]
Abstract
Pathologic alterations in podocytes lead to failure of an essential component of the glomerular filtration barrier and proteinuria in chronic kidney diseases. Elevated levels of saturated free fatty acid (FFA) are harmful to various tissues, implemented in the progression of diabetes and its complications such as proteinuria in diabetic nephropathy. Here, we investigated the molecular mechanism of palmitate cytotoxicity in cultured mouse podocytes. Incubation with palmitate dose-dependently increased cytosolic and mitochondrial reactive oxygen species, depolarized the mitochondrial membrane potential, impaired ATP synthesis and elicited apoptotic cell death. Palmitate not only evoked mitochondrial fragmentation but also caused marked dilation of the endoplasmic reticulum (ER). Consistently, palmitate upregulated ER stress proteins, oligomerized stromal interaction molecule 1 (STIM1) in the subplasmalemmal ER membrane, abolished the cyclopiazonic acid-induced cytosolic Ca2+ increase due to depletion of luminal ER Ca2+. Palmitate-induced ER Ca2+ depletion and cytotoxicity were blocked by a selective inhibitor of the fatty-acid transporter FAT/CD36. Loss of the ER Ca2+ pool induced by palmitate was reverted by the phospholipase C (PLC) inhibitor edelfosine. Palmitate-dependent activation of PLC was further demonstrated by following cytosolic translocation of the pleckstrin homology domain of PLC in palmitate-treated podocytes. An inhibitor of diacylglycerol (DAG) kinase, which elevates cytosolic DAG, strongly promoted ER Ca2+ depletion by low-dose palmitate. GF109203X, a PKC inhibitor, partially prevented palmitate-induced ER Ca2+ loss. Remarkably, the mitochondrial antioxidant mitoTEMPO inhibited palmitate-induced PLC activation, ER Ca2+ depletion and cytotoxicity. Palmitate elicited cytoskeletal changes in podocytes and increased albumin permeability, which was also blocked by mitoTEMPO. These data suggest that oxidative stress caused by saturated FFA leads to mitochondrial dysfunction and ER Ca2+ depletion through FAT/CD36 and PLC signaling, possibly contributing to podocyte injury.
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Affiliation(s)
- S Xu
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - S M Nam
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea.,Department of Internal Medicine, Daejeon Sun Hospital, Daejeon, Korea
| | - J-H Kim
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - R Das
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - S-K Choi
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - T T Nguyen
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - X Quan
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - S J Choi
- Department of Microbiology, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - C H Chung
- Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - E Y Lee
- Department of Internal Medicine, Soonchunhyang University Cheonan Hospital, Cheonan, Korea
| | - I-K Lee
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - A Wiederkehr
- Nestlé Institute of Health Sciences, Lausanne, Switzerland
| | - C B Wollheim
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - S-K Cha
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
| | - K-S Park
- Department of Physiology and Institute of Lifestyle Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea
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138
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Ising C, Koehler S, Brähler S, Merkwirth C, Höhne M, Baris OR, Hagmann H, Kann M, Fabretti F, Dafinger C, Bloch W, Schermer B, Linkermann A, Brüning JC, Kurschat CE, Müller RU, Wiesner RJ, Langer T, Benzing T, Brinkkoetter PT. Inhibition of insulin/IGF-1 receptor signaling protects from mitochondria-mediated kidney failure. EMBO Mol Med 2015; 7:275-87. [PMID: 25643582 PMCID: PMC4364945 DOI: 10.15252/emmm.201404916] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial dysfunction and alterations in energy metabolism have been implicated in a variety of human diseases. Mitochondrial fusion is essential for maintenance of mitochondrial function and requires the prohibitin ring complex subunit prohibitin-2 (PHB2) at the mitochondrial inner membrane. Here, we provide a link between PHB2 deficiency and hyperactive insulin/IGF-1 signaling. Deletion of PHB2 in podocytes of mice, terminally differentiated cells at the kidney filtration barrier, caused progressive proteinuria, kidney failure, and death of the animals and resulted in hyperphosphorylation of S6 ribosomal protein (S6RP), a known mediator of the mTOR signaling pathway. Inhibition of the insulin/IGF-1 signaling system through genetic deletion of the insulin receptor alone or in combination with the IGF-1 receptor or treatment with rapamycin prevented hyperphosphorylation of S6RP without affecting the mitochondrial structural defect, alleviated renal disease, and delayed the onset of kidney failure in PHB2-deficient animals. Evidently, perturbation of insulin/IGF-1 receptor signaling contributes to tissue damage in mitochondrial disease, which may allow therapeutic intervention against a wide spectrum of diseases.
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Affiliation(s)
- Christina Ising
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Sybille Koehler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Sebastian Brähler
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Carsten Merkwirth
- Institute for Genetics, University of Cologne, Cologne, Germany Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Martin Höhne
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Olivier R Baris
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Henning Hagmann
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Martin Kann
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Francesca Fabretti
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Claudia Dafinger
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Andreas Linkermann
- Division of Nephrology and Hypertension, Christian-Albrechts-University, Kiel, Germany
| | - Jens C Brüning
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany Max Planck Institute for Metabolism Research, Cologne, Germany Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany
| | - Christine E Kurschat
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Roman-Ulrich Müller
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute for Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Thomas Langer
- Institute for Genetics, University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD) and Systems Biology of Ageing Cologne (Sybacol) University of Cologne, Cologne, Germany
| | - Paul Thomas Brinkkoetter
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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139
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Lal MA, Young KW, Andag U. Targeting the podocyte to treat glomerular kidney disease. Drug Discov Today 2015; 20:1228-34. [DOI: 10.1016/j.drudis.2015.06.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/28/2015] [Accepted: 06/11/2015] [Indexed: 12/19/2022]
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140
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MOF maintains transcriptional programs regulating cellular stress response. Oncogene 2015; 35:2698-710. [PMID: 26387537 PMCID: PMC4893634 DOI: 10.1038/onc.2015.335] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 07/09/2015] [Accepted: 08/04/2015] [Indexed: 12/14/2022]
Abstract
MOF (MYST1, KAT8) is the major H4K16 lysine acetyltransferase (KAT) in Drosophila and mammals and is essential for embryonic development. However, little is known regarding the role of MOF in specific cell lineages. Here we analyze the differential role of MOF in proliferating and terminally differentiated tissues at steady state and under stress conditions. In proliferating cells, MOF directly binds and maintains the expression of genes required for cell cycle progression. In contrast, MOF is dispensable for terminally differentiated, postmitotic glomerular podocytes under physiological conditions. However, in response to injury, MOF is absolutely critical for podocyte maintenance in vivo. Consistently, we detect defective nuclear, endoplasmic reticulum and Golgi structures, as well as presence of multivesicular bodies in vivo in podocytes lacking Mof following injury. Undertaking genome-wide expression analysis of podocytes, we uncover several MOF-regulated pathways required for stress response. We find that MOF, along with the members of the non-specific lethal but not the male-specific lethal complex, directly binds to genes encoding the lysosome, endocytosis and vacuole pathways, which are known regulators of podocyte maintenance. Thus, our work identifies MOF as a key regulator of cellular stress response in glomerular podocytes.
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141
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Xiang L, Mittwede PN, Clemmer JS. Glucose Homeostasis and Cardiovascular Alterations in Diabetes. Compr Physiol 2015; 5:1815-39. [DOI: 10.1002/cphy.c150001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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142
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Abstract
OBJECTIVES Nephrin is an integral part of podocytes that together with endothelial cells and the basement form the glomerular filtration barrier. Placental ischemia triggers a cascade of events that ultimately result in endothelial malfunction, hypertension, podocytopathy and fetal compromise. METHODS We review the literature to determine if urine nephrin measurements could serve as a useful biomarker to detect early podocyte injury in pre-eclampsia. RESULTS Our search identifies eight studies published to date. The findings of these studies demonstrate that urine nephrin excretion plays a critical role in the pathogenesis of proteinuria during pre-eclampsia and that this is a good indicator of glomerular injury. CONCLUSION There is thus an urgent need for a large multi-centre clinical study using standardized recruitment criteria to determine the full potential of this biomarker in clinical practice.
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Affiliation(s)
- Yogavijayan Kandasamy
- a Department of Neonatology , The Townsville Hospital , Douglas , Queensland , Australia .,b Mothers and Babies Research Centre, Hunter Medical Research Institute, John Hunter Hospital, The University of Newcastle , Callaghan , New South Wales , Australia .,c College of Public Health, Medical and Veterinary Sciences, The James Cook University , Townsville City , Queensland , Australia , and
| | - David Watson
- d Department of Obstetrics and Gynaecology , The Townsville Hospital , Douglas , Queensland , Australia
| | - Donna Rudd
- c College of Public Health, Medical and Veterinary Sciences, The James Cook University , Townsville City , Queensland , Australia , and
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143
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Rinschen MM, Benzing T, Limbutara K, Pisitkun T. Proteomic analysis of the kidney filtration barrier--Problems and perspectives. Proteomics Clin Appl 2015; 9:1053-68. [PMID: 25907645 DOI: 10.1002/prca.201400201] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 03/21/2015] [Accepted: 04/20/2015] [Indexed: 12/12/2022]
Abstract
Diseases of the glomerular filter of the kidney are a leading cause of end-stage renal failure. The kidney filter is localized within the renal glomeruli, small microvascular units that are responsible for ultrafiltration of about 180 liters of primary urine every day. The renal filter consists of three layers, fenestrated endothelial cells, glomerular basement membrane, and the podocytes, terminally differentiated, arborized epithelial cells. This review demonstrates the use of proteomics to generate insights into the regulation of the renal filtration barrier at a molecular level. The advantages and disadvantages of different glomerular purification methods are examined, and the technical limitations that have been significantly improved by in silico or biochemical approaches are presented. We also comment on phosphoproteomic studies that have generated considerable molecular-level understanding of the physiological regulation of the kidney filter. Lastly, we conclude with an analysis of urinary exosomes as a potential filter-derived resource for the noninvasive discovery of glomerular disease mechanisms.
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Affiliation(s)
- Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany
| | - Kavee Limbutara
- Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Trairak Pisitkun
- Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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144
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Dong L, Pietsch S, Englert C. Towards an understanding of kidney diseases associated with WT1 mutations. Kidney Int 2015; 88:684-90. [PMID: 26154924 PMCID: PMC4687464 DOI: 10.1038/ki.2015.198] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/12/2015] [Indexed: 12/23/2022]
Abstract
Mutations in Wilms' tumor 1 (WT1) cause a wide spectrum of renal manifestations, eventually leading to end-stage kidney failure. Insufficient understanding of WT1's molecular functions in kidney development has hampered efficient therapeutic applications for WT1-associated diseases. Recently, the generation and characterization of mouse models and application of multiple state-of-the-art approaches have significantly expanded our understanding of the molecular mechanisms of how WT1 mutations lead to kidney failure. Here, we discuss the WT1 binding consensus and illustrate the major roles of WT1 in different cell populations in kidney biology. WT1 controls metanephric mesenchyme (MM) self-renewal and proliferation mainly by regulating FGF and BMP-pSMAD signaling pathways as well as Sall1 and Pax2, encoding key transcription factors; WT1 drives MM differentiation and mesenchyme–epithelial transition by targeting Fgf8 and Wnt4; WT1 defines podocyte identity by activation of other podocyte-specific transcription factors, including Mafb, Lmx1b, FoxC2, and Tcf21. These factors potentially cooperate with WT1 regulating the expression of components and regulators of the cytoskeleton for establishing podocyte polarity, slit diaphragm structure, and focal adhesion to the glomerular basement membrane. Understanding of WT1's function in kidney biology including WT1-regulated pathways will give insights that will eventually help therapeutic applications.
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Affiliation(s)
- Lihua Dong
- Molecular Genetics, Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany
| | - Stefan Pietsch
- Molecular Genetics, Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany
| | - Christoph Englert
- Molecular Genetics, Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany.,Faculty of Biology and Pharmacy, Friedrich Schiller University of Jena, Jena, Germany
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145
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Wnt/β-catenin signalling and podocyte dysfunction in proteinuric kidney disease. Nat Rev Nephrol 2015; 11:535-45. [PMID: 26055352 DOI: 10.1038/nrneph.2015.88] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Podocytes are unique, highly specialized, terminally differentiated cells that are integral components of the kidney glomerular filtration barrier. Podocytes are vulnerable to a variety of injuries and in response they undergo a series of changes ranging from hypertrophy, autophagy, dedifferentiation, mesenchymal transition and detachment to apoptosis, depending on the nature and extent of the insult. Emerging evidence indicates that Wnt/β-catenin signalling has a central role in mediating podocyte dysfunction and proteinuria. Wnts are induced and β-catenin is activated in podocytes in various proteinuric kidney diseases. Genetic or pharmacologic activation of β-catenin is sufficient to impair podocyte integrity and causes proteinuria in healthy mice, whereas podocyte-specific ablation of β-catenin protects against proteinuria after kidney injury. Mechanistically, Wnt/β-catenin controls the expression of several key mediators implicated in podocytopathies, including Snail1, the renin-angiotensin system and matrix metalloproteinase 7. Wnt/β-catenin also negatively regulates Wilms tumour protein, a crucial transcription factor that safeguards podocyte integrity. Targeted inhibition of Wnt/β-catenin signalling preserves podocyte integrity and ameliorates proteinuria in animal models. This Review highlights advances in our understanding of the pathomechanisms of Wnt/β-catenin signalling in mediating podocyte injury, and describes the therapeutic potential of targeting this pathway for the treatment of proteinuric kidney disease.
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146
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Sugahara G, Naito I, Miyagawa Y, Komiyama T, Takemura N, Kobayashi R, Mineshige T, Kamiie J, Shirota K. Pathological features of proteinuric nephropathy resembling Alport syndrome in a young Pyrenean Mountain dog. J Vet Med Sci 2015; 77:1175-8. [PMID: 25892536 PMCID: PMC4591163 DOI: 10.1292/jvms.15-0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The renal biopsy tissue from a 9-month-old, male Pyrenean Mountain dog with renal disorder and severe proteinuria was examined. Ultrastructural examination revealed multilaminar splitting and fragmentation of the glomerular basement membrane (GBM) and diffuse podocyte foot process effacement. Immunofluorescent staining for α(IV) chains revealed presence of α5(IV) and complete absence of α3(IV) and α4(IV) chains in the GBM. Immunohistochemistry also revealed decreased and altered expression of nephrin and podocin in the glomeruli compared with normal canine glomeruli. These results suggested that the glomerular disease of the present case might be consistent with canine hereditary nephropathy resembling human Alport syndrome caused by genetic defect of type IV collagen, and indicated possible contribution of podocyte injury to severe proteinuria in this case.
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Affiliation(s)
- Go Sugahara
- Laboratory of Veterinary Pathology, School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5201, Japan
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147
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Perisic L, Rodriguez PQ, Hultenby K, Sun Y, Lal M, Betsholtz C, Uhlén M, Wernerson A, Hedin U, Pikkarainen T, Tryggvason K, Patrakka J. Schip1 is a novel podocyte foot process protein that mediates actin cytoskeleton rearrangements and forms a complex with Nherf2 and ezrin. PLoS One 2015; 10:e0122067. [PMID: 25807495 PMCID: PMC4373682 DOI: 10.1371/journal.pone.0122067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 02/18/2015] [Indexed: 01/28/2023] Open
Abstract
Background Podocyte foot process effacement accompanied by actin cytoskeleton rearrangements is a cardinal feature of many progressive human proteinuric diseases. Results By microarray profiling of mouse glomerulus, SCHIP1 emerged as one of the most highly enriched transcripts. We detected Schip1 protein in the kidney glomerulus, specifically in podocytes foot processes. Functionally, Schip1 inactivation in zebrafish by morpholino knock-down results in foot process disorganization and podocyte loss leading to proteinuria. In cultured podocytes Schip1 localizes to cortical actin-rich regions of lamellipodia, where it forms a complex with Nherf2 and ezrin, proteins known to participate in actin remodeling stimulated by PDGFβ signaling. Mechanistically, overexpression of Schip1 in vitro causes accumulation of cortical F-actin with dissolution of transversal stress fibers and promotes cell migration in response to PDGF-BB stimulation. Upon actin disassembly by latrunculin A treatment, Schip1 remains associated with the residual F-actin-containing structures, suggesting a functional connection with actin cytoskeleton possibly via its interaction partners. A similar assay with cytochalasin D points to stabilization of cortical actin cytoskeleton in Schip1 overexpressing cells by attenuation of actin depolymerisation. Conclusions Schip1 is a novel glomerular protein predominantly expressed in podocytes, necessary for the zebrafish pronephros development and function. Schip1 associates with the cortical actin cytoskeleton network and modulates its dynamics in response to PDGF signaling via interaction with the Nherf2/ezrin complex. Its implication in proteinuric diseases remains to be further investigated.
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Affiliation(s)
- Ljubica Perisic
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- Division of Vascular Surgery, Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - Patricia Q. Rodriguez
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Kjell Hultenby
- Clinical Research Center, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Ying Sun
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Mark Lal
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Christer Betsholtz
- Vascular Biology Division, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Mathias Uhlén
- Department of Biotechnology, Royal Institute of Technology, Stockholm, Sweden
| | - Annika Wernerson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
| | - Ulf Hedin
- Division of Vascular Surgery, Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - Timo Pikkarainen
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Karl Tryggvason
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Jaakko Patrakka
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- * E-mail:
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148
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Kann M, Ettou S, Jung YL, Lenz MO, Taglienti ME, Park PJ, Schermer B, Benzing T, Kreidberg JA. Genome-Wide Analysis of Wilms' Tumor 1-Controlled Gene Expression in Podocytes Reveals Key Regulatory Mechanisms. J Am Soc Nephrol 2015; 26:2097-104. [PMID: 25636411 DOI: 10.1681/asn.2014090940] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 12/24/2014] [Indexed: 01/12/2023] Open
Abstract
The transcription factor Wilms' tumor suppressor 1 (WT1) is key to podocyte development and viability; however, WT1 transcriptional networks in podocytes remain elusive. We provide a comprehensive analysis of the genome-wide WT1 transcriptional network in podocytes in vivo using chromatin immunoprecipitation followed by sequencing (ChIPseq) and RNA sequencing techniques. Our data show a specific role for WT1 in regulating the podocyte-specific transcriptome through binding to both promoters and enhancers of target genes. Furthermore, we inferred a podocyte transcription factor network consisting of WT1, LMX1B, TCF21, Fox-class and TEAD family transcription factors, and MAFB that uses tissue-specific enhancers to control podocyte gene expression. In addition to previously described WT1-dependent target genes, ChIPseq identified novel WT1-dependent signaling systems. These targets included components of the Hippo signaling system, underscoring the power of genome-wide transcriptional-network analyses. Together, our data elucidate a comprehensive gene regulatory network in podocytes suggesting that WT1 gene regulatory function and podocyte cell-type specification can best be understood in the context of transcription factor-regulatory element network interplay.
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Affiliation(s)
- Martin Kann
- Division of Nephrology, Department of Medicine and Department II of Internal Medicine and Center for Molecular Medicine Cologne and
| | | | - Youngsook L Jung
- Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts; Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Maximilian O Lenz
- Department II of Internal Medicine and Center for Molecular Medicine Cologne and
| | | | - Peter J Park
- Center for Biomedical Informatics, Harvard Medical School, Boston, Massachusetts; Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts; Informatics Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne and Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases, Cologne, Germany; and Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne and Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases, Cologne, Germany; and Systems Biology of Ageing Cologne, University of Cologne, Cologne, Germany;
| | - Jordan A Kreidberg
- Division of Nephrology, Department of Medicine and Harvard Stem Cell Institute, Cambridge, Massachusetts
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149
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Tanaka M, Furuhashi M, Okazaki Y, Mita T, Fuseya T, Ohno K, Ishimura S, Yoshida H, Miura T. Ectopic expression of fatty acid-binding protein 4 in the glomerulus is associated with proteinuria and renal dysfunction. Nephron Clin Pract 2015; 128:345-51. [PMID: 25592475 DOI: 10.1159/000368412] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 09/17/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Fatty acid-binding proteins (FABPs) are a family of intracellular lipid chaperones. Among FABPs, FABP1 (liver FABP) is expressed in proximal tubular epithelial cells in the kidney, and urinary FABP1 has been reported to reflect damage of proximal tubular epithelial cells. However, roles of other FABP isoforms in renal pathologies have not been reported. Recently, FABP4 (adipocyte FABP/aP2) was reported to be expressed in peritubular capillaries (PTCs), but not in glomerular capillaries in the normal kidney. We examined the hypothesis that pathological conditions alter the level and localization of FABP4 expression in the kidney, which mediates renal dysfunction. METHODS A total of 112 consecutive patients who underwent renal biopsy were retrospectively enrolled. Expression of FABP4 protein and mRNA in the kidney was examined by immunohistochemistry and in situ hybridization, respectively. The ratio of FABP4-positive area to total area within glomeruli (G-FABP4-Area), urinary protein level (U-Protein), and change in estimated glomerular filtration rate (eGFR) 1 year after biopsy were examined. RESULTS FABP4 protein and mRNA were expressed not only in PTCs, but also in endothelial cells and macrophages in the glomerulus. G-FABP4-Area was correlated with U-Protein (r = 0.497, p < 0.001). As a subanalysis, in patients with IgA nephropathy (n = 34), G-FABP4-Area was significantly larger in cases with an endocapillary proliferative lesion, and change in eGFR was negatively correlated with G-FABP4-Area at baseline (r = -0.537, p = 0.008). CONCLUSION Ectopic FABP4 expression in the glomerulus is induced by renal diseases and is closely associated with proteinuria and renal dysfunction.
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Affiliation(s)
- Marenao Tanaka
- Department of Cardiovascular, Renal and Metabolic Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan
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150
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Dong L, Pietsch S, Tan Z, Perner B, Sierig R, Kruspe D, Groth M, Witzgall R, Gröne HJ, Platzer M, Englert C. Integration of Cistromic and Transcriptomic Analyses Identifies Nphs2, Mafb, and Magi2 as Wilms' Tumor 1 Target Genes in Podocyte Differentiation and Maintenance. J Am Soc Nephrol 2015; 26:2118-28. [PMID: 25556170 DOI: 10.1681/asn.2014080819] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 10/10/2014] [Indexed: 11/03/2022] Open
Abstract
The Wilms' tumor suppressor gene 1 (WT1) encodes a zinc finger transcription factor. Mutation of WT1 in humans leads to Wilms' tumor, a pediatric kidney tumor, or other kidney diseases, such as Denys-Drash and Frasier syndromes. We showed previously that inactivation of WT1 in podocytes of adult mice results in proteinuria, foot process effacement, and glomerulosclerosis. However, the WT1-dependent transcriptional network regulating podocyte development and maintenance in vivo remains unknown. Here, we performed chromatin immunoprecipitation followed by high-throughput sequencing with glomeruli from wild-type mice. Additionally, we performed a cDNA microarray screen on an inducible podocyte-specific WT1 knockout mouse model. By integration of cistromic and transcriptomic analyses, we identified the WT1 targetome in mature podocytes. To further analyze the function and targets of WT1 in podocyte maturation, we used an Nphs2-Cre model, in which WT1 is deleted during podocyte differentiation. These mice display anuria and kidney hemorrhage and die within 24 hours after birth. To address the evolutionary conservation of WT1 targets, we performed functional assays using zebrafish as a model and identified Nphs2, Mafb, and Magi2 as novel WT1 target genes required for podocyte development. Our data also show that both Mafb and Magi2 are required for normal development of the embryonic zebrafish kidney. Collectively, our work provides insights into the transcriptional networks controlled by WT1 and identifies novel WT1 target genes that mediate the function of WT1 in podocyte differentiation and maintenance.
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Affiliation(s)
| | | | | | | | | | | | - Marco Groth
- Genome Analysis, Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany
| | - Ralph Witzgall
- Institute for Molecular and Cellular Anatomy, University of Regensburg, Regensburg, Germany
| | - Hermann-Josef Gröne
- Department of Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany; and
| | - Matthias Platzer
- Genome Analysis, Leibniz Institute for Age Research, Fritz Lipmann Institute, Jena, Germany
| | - Christoph Englert
- Departments of Molecular Genetics and Faculty of Biology and Pharmacy, Friedrich Schiller University of Jena, Jena, Germany
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