51
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Kuppe C, van Roeyen C, Leuchtle K, Kabgani N, Vogt M, Van Zandvoort M, Smeets B, Floege J, Gröne HJ, Moeller MJ. Investigations of Glucocorticoid Action in GN. J Am Soc Nephrol 2016; 28:1408-1420. [PMID: 27895155 DOI: 10.1681/asn.2016010060] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 10/04/2016] [Indexed: 12/21/2022] Open
Abstract
For several decades, glucocorticoids have been used empirically to treat rapid progressive GN. It is commonly assumed that glucocorticoids act primarily by dampening the immune response, but the mechanisms remain incompletely understood. In this study, we inactivated the glucocorticoid receptor (GR) specifically in kidney epithelial cells using Pax8-Cre/GRfl/fl mice. Pax8-Cre/GRfl/fl mice did not exhibit an overt spontaneous phenotype. In mice treated with nephrotoxic serum to induce crescentic nephritis (rapidly progressive GN), this genetic inactivation of the GR in kidney epithelial cells exerted renal benefits, including inhibition of albuminuria and cellular crescent formation, similar to the renal benefits observed with high-dose prednisolone in control mice. However, genetic inactivation of the GR in kidney epithelial cells did not induce the immunosuppressive effects observed with prednisolone. In vitro, prednisolone and the pharmacologic GR antagonist mifepristone each acted directly on primary cultures of parietal epithelial cells, inhibiting cellular outgrowth and proliferation. In wild-type mice, pharmacologic treatment with the GR antagonist mifepristone also attenuated disease as effectively as high-dose prednisolone without the systemic immunosuppressive effects. Collectively, these data show that glucocorticoids act directly on activated glomerular parietal epithelial cells in crescentic nephritis. Furthermore, we identified a novel therapeutic approach in crescentic nephritis, that of glucocorticoid antagonism, which was at least as effective as high-dose prednisolone with potentially fewer adverse effects.
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Affiliation(s)
- Christoph Kuppe
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany
| | - Claudia van Roeyen
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany
| | - Katja Leuchtle
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany.,Interdisciplinary Centre for Clinical Research, Rheinisch-Westfälische Technische Hochschule Aachen University Hospital, Aachen, Germany
| | - Nazanin Kabgani
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany
| | - Michael Vogt
- Interdisciplinary Centre for Clinical Research, Rheinisch-Westfälische Technische Hochschule Aachen University Hospital, Aachen, Germany
| | - Marc Van Zandvoort
- Interdisciplinary Centre for Clinical Research, Rheinisch-Westfälische Technische Hochschule Aachen University Hospital, Aachen, Germany.,Department of Genetics and Cell Biology, Sector Molecular Cell Biology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Bart Smeets
- Department of Pathology, Radboud University, Nijmegen, The Netherlands; and
| | - Jürgen Floege
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany
| | - Hermann-Josef Gröne
- Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany
| | - Marcus J Moeller
- Division of Nephrology and Clinical Immunology, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany; .,Interdisciplinary Centre for Clinical Research, Rheinisch-Westfälische Technische Hochschule Aachen University Hospital, Aachen, Germany
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52
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Mallipattu SK, Estrada CC, He JC. The critical role of Krüppel-like factors in kidney disease. Am J Physiol Renal Physiol 2016; 312:F259-F265. [PMID: 27852611 DOI: 10.1152/ajprenal.00550.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/11/2016] [Accepted: 11/12/2016] [Indexed: 01/27/2023] Open
Abstract
Krüppel-like factors (KLFs) are a family of zinc-finger transcription factors critical to mammalian embryonic development, regeneration, and human disease. There is emerging evidence that KLFs play a vital role in key physiological processes in the kidney, ranging from maintenance of glomerular filtration barrier to tubulointerstitial inflammation to progression of kidney fibrosis. Seventeen members of the KLF family have been identified, and several have been well characterized in the kidney. Although they may share some overlap in their downstream targets, their structure and function remain distinct. This review highlights our current knowledge of KLFs in the kidney, which includes their pattern of expression and their function in regulating key biological processes. We will also critically examine the currently available literature on KLFs in the kidney and offer some key areas in need of further investigation.
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Affiliation(s)
- Sandeep K Mallipattu
- Division of Nephrology, Department of Medicine, Stony Brook University School of Medicine, New York, New York;
| | - Chelsea C Estrada
- Division of Nephrology, Department of Medicine, Stony Brook University School of Medicine, New York, New York
| | - John C He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and.,Renal Section, James J. Peters Veterans Affairs Medical Center, New York, New York
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53
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Minimal change disease and idiopathic FSGS: manifestations of the same disease. Nat Rev Nephrol 2016; 12:768-776. [DOI: 10.1038/nrneph.2016.147] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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54
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Gong W, Yu J, Wang Q, Li S, Song J, Jia Z, Huang S, Zhang A. Estrogen-related receptor (ERR) γ protects against puromycin aminonucleoside-induced podocyte apoptosis by targeting PI3K/Akt signaling. Int J Biochem Cell Biol 2016; 78:75-86. [PMID: 27417234 DOI: 10.1016/j.biocel.2016.07.005] [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: 10/26/2015] [Revised: 07/06/2016] [Accepted: 07/08/2016] [Indexed: 12/21/2022]
Abstract
Accumulating evidence has shown that podocyte apoptosis is of vital importance for the development of glomerulosclerosis and progressive loss of renal function. However, the molecular mechanisms leading to podocyte apoptosis are still elusive. In this study, we investigated the role of estrogen-related receptor (ERR) γ in podocyte apoptosis, as well as the underlying mechanisms. Treatment of PAN caused a dose- and time-dependent podocyte apoptosis in line with a significant downregulation of ERRγ. Interestingly, the occurrence of ERRγ downregulation appeared earlier than the onset of cell apoptosis, suggesting a potential that ERRγ reduction triggered apoptotic response in podocyte. To test this hypothesis, ERRγ siRNA was administered to the podocytes. Strikingly, ERRγ silencing resulted in a significant cell apoptosis accompanied with increased injury markers of B7-1 and cathepsin L and decreased podocyte protein nephrin. In contrast, overexpression of ERRγ remarkably attenuated PAN-induced cell apoptosis. Moreover, ERRγ overexpression stimulated PI3K/Akt signaling pathway evidenced by increased expression of PI3K subunits p85α and p110α and phosphorylated Akt. Importantly, a specific PI3K inhibitor LY294002 entirely reversed the anti-apoptotic effect of ERRγ following PAN treatment. Finally, we observed a striking downregulation of ERRγ in PAN-treated rat kidneys, suggesting that our cell model replicated the in vivo condition. Taken together, these data highly suggested that ERRγ played a novel role in modulating podocyte apoptosis by targeting PI3K/Akt signaling pathway.
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Affiliation(s)
- Wei Gong
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Jing Yu
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Qilei Wang
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Shuzhen Li
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China
| | - Jiayu Song
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China
| | - Zhanjun Jia
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China
| | - Songming Huang
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China
| | - Aihua Zhang
- Department of Nephrology, Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing 210008, China; State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 210029, China; Jiangsu Key Laboratory of Pediatrics, Nanjing Medical University, Nanjing 210029, China; Nanjing Key Laboratory of Pediatrics, Nanjing 210008, China.
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55
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Abstract
Focal segmental glomerulosclerosis, which is a common glomerular disorder, manifests clinically with a nephrotic syndrome and has a high propensity for recurrence after kidney transplantation. The pathophysiology is currently unknown, and podocytes appear to be the target of one or several circulating factor(s) that lead to the recurrence of proteinuria after kidney transplantation. Identifying these circulating factor(s) and cells involved in its synthesis remains elusive; however, recently, our research on podocyte cytoskeleton biology has opened a new era of treatment. This review will highlight recent progress in the physiopathology of focal segmental glomerulosclerosis recurrence after transplantation and its treatment.
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56
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Mallipattu SK, Guo Y, Revelo MP, Roa-Peña L, Miller T, Ling J, Shankland SJ, Bialkowska AB, Ly V, Estrada C, Jain MK, Lu Y, Ma'ayan A, Mehrotra A, Yacoub R, Nord EP, Woroniecki RP, Yang VW, He JC. Krüppel-Like Factor 15 Mediates Glucocorticoid-Induced Restoration of Podocyte Differentiation Markers. J Am Soc Nephrol 2016; 28:166-184. [PMID: 27288011 DOI: 10.1681/asn.2015060672] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 04/05/2016] [Indexed: 12/18/2022] Open
Abstract
Podocyte injury is the inciting event in primary glomerulopathies, such as minimal change disease and primary FSGS, and glucocorticoids remain the initial and often, the primary treatment of choice for these glomerulopathies. Because inflammation is not readily apparent in these diseases, understanding the direct effects of glucocorticoids on the podocyte, independent of the immunomodulatory effects, may lead to the identification of targets downstream of glucocorticoids that minimize toxicity without compromising efficacy. Several studies showed that treatment with glucocorticoids restores podocyte differentiation markers and normal ultrastructure and improves cell survival in murine podocytes. We previously determined that Krüppel-like factor 15 (KLF15), a kidney-enriched zinc finger transcription factor, is required for restoring podocyte differentiation markers in mice and human podocytes under cell stress. Here, we show that in vitro treatment with dexamethasone induced a rapid increase of KLF15 expression in human and murine podocytes and enhanced the affinity of glucocorticoid receptor binding to the promoter region of KLF15 In three independent proteinuric murine models, podocyte-specific loss of Klf15 abrogated dexamethasone-induced podocyte recovery. Furthermore, knockdown of KLF15 reduced cell survival and destabilized the actin cytoskeleton in differentiated human podocytes. Conversely, overexpression of KLF15 stabilized the actin cytoskeleton under cell stress in human podocytes. Finally, the level of KLF15 expression in the podocytes and glomeruli from human biopsy specimens correlated with glucocorticoid responsiveness in 35 patients with minimal change disease or primary FSGS. Thus, these studies identify the critical role of KLF15 in mediating the salutary effects of glucocorticoids in the podocyte.
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Affiliation(s)
| | - Yiqing Guo
- Division of Nephrology, Departments of Medicine and
| | - Monica P Revelo
- Department of Pathology, University of Utah, Salt Lake City, Utah
| | | | | | - Jason Ling
- Division of Nephrology, Departments of Medicine and
| | - Stuart J Shankland
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington
| | - Agnieszka B Bialkowska
- Division of Gastroenterology, Department of Medicine, Stony Brook University, Stony Brook, New York
| | - Victoria Ly
- Division of Nephrology, Departments of Medicine and
| | | | - Mukesh K Jain
- Case Cardiovascular Institute Research Institute, Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Yuan Lu
- Case Cardiovascular Institute Research Institute, Department of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Avi Ma'ayan
- Department of Pharmacology and Systems Therapeutics and
| | - Anita Mehrotra
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Rabi Yacoub
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | | | | | - Vincent W Yang
- Division of Gastroenterology, Department of Medicine, Stony Brook University, Stony Brook, New York
| | - John C He
- Department of Pharmacology and Systems Therapeutics and.,Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and.,Renal Section, James J. Peters Veterans Affairs Medical Center, New York, New York
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57
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Mallipattu SK, He JC. The podocyte as a direct target for treatment of glomerular disease? Am J Physiol Renal Physiol 2016; 311:F46-51. [PMID: 27097894 DOI: 10.1152/ajprenal.00184.2016] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/18/2016] [Indexed: 11/22/2022] Open
Abstract
The Centers for Disease Control and Prevention estimates more than 10% of adults in the United States, over 20 million Americans, have chronic kidney disease (CKD). A failure to maintain the glomerular filtration barrier directly contributes to the onset of CKD. The visceral epithelial cells, podocytes, are integral to the maintenance of this renal filtration barrier. Direct podocyte injury contributes to the onset and progression of glomerular diseases such as minimal change disease (MCD), focal segmental glomerular sclerosis (FSGS), diabetic nephropathy, and HIV-associated nephropathy (HIVAN). Since podocytes are terminally differentiated with minimal capacity to self-replicate, they are extremely sensitive to cellular injury. In the past two decades, our understanding of the mechanism(s) by which podocyte injury occurs has greatly expanded. With this newfound knowledge, therapeutic strategies have shifted to identifying targets directed specifically at the podocyte. Although the systemic effects of these agents are important, their direct effect on the podocyte proves to be essential in ameliorating glomerular disease. In this review, we highlight the mechanisms by which these agents directly target the podocyte independent of its systemic effects.
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Affiliation(s)
- Sandeep K Mallipattu
- Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, New York
| | - John C He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and Renal Section, James J. Peters VA Medical Center, New York, New York
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58
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Lichtnekert J, Kaverina NV, Eng DG, Gross KW, Kutz JN, Pippin JW, Shankland SJ. Renin-Angiotensin-Aldosterone System Inhibition Increases Podocyte Derivation from Cells of Renin Lineage. J Am Soc Nephrol 2016; 27:3611-3627. [PMID: 27080979 DOI: 10.1681/asn.2015080877] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 02/20/2016] [Indexed: 12/17/2022] Open
Abstract
Because adult podocytes cannot proliferate and are therefore unable to self-renew, replacement of these cells depends on stem/progenitor cells. Although podocyte number is higher after renin-angiotensin-aldosterone system (RAAS) inhibition in glomerular diseases, the events explaining this increase are unclear. Cells of renin lineage (CoRL) have marked plasticity, including the ability to acquire a podocyte phenotype. To test the hypothesis that RAAS inhibition partially replenishes adult podocytes by increasing CoRL number, migration, and/or transdifferentiation, we administered tamoxifen to Ren1cCreERxRs-tdTomato-R CoRL reporter mice to induce permanent labeling of CoRL with red fluorescent protein variant tdTomato. We then induced experimental FSGS, typified by abrupt podocyte depletion, with a cytopathic antipodocyte antibody. RAAS inhibition by enalapril (angiotensin-converting enzyme inhibitor) or losartan (angiotensin-receptor blocker) in FSGS mice stimulated the proliferation of CoRL, increasing the reservoir of these cells in the juxtaglomerular compartment (JGC). Compared with water or hydralazine, RAAS inhibition significantly increased the migration of CoRL from the JGC to the intraglomerular compartment (IGC), with more glomeruli containing RFP+CoRL and, within these glomeruli, more RFP+CoRL. Moreover, RAAS inhibition in FSGS mice increased RFP+CoRL transdifferentiation in the IGC to phenotypes, consistent with those of podocytes (coexpression of synaptopodin and Wilms tumor protein), parietal epithelial cells (PAX 8), and mesangial cells (α8 integrin). These results show that in the context of podocyte depletion in FSGS, RAAS inhibition augments CoRL proliferation and plasticity toward three different glomerular cell lineages.
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Affiliation(s)
| | | | | | - Kenneth W Gross
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York
| | - J Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, Washington; and
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59
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Elvin J, Buvall L, Lindskog Jonsson A, Granqvist A, Lassén E, Bergwall L, Nyström J, Haraldsson B. Melanocortin 1 receptor agonist protects podocytes through catalase and RhoA activation. Am J Physiol Renal Physiol 2016; 310:F846-56. [PMID: 26887829 DOI: 10.1152/ajprenal.00231.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 02/15/2016] [Indexed: 11/22/2022] Open
Abstract
Drugs containing adrenocorticotropic hormone have been used as therapy for patients with nephrotic syndrome. We have previously shown that adrenocorticotropic hormone and a selective agonist for the melanocortin 1 receptor (MC1R) exert beneficial actions in experimental membranous nephropathy with reduced proteinuria, reduced oxidative stress, and improved glomerular morphology and function. Our hypothesis is that MC1R activation in podocytes elicits beneficial effects by promoting stress fibers and maintaining podocyte viability. To test the hypothesis, we cultured podocytes and used highly specific agonists for MC1R. Podocytes were subjected to the nephrotic-inducing agent puromycin aminonucleoside, and downstream effects of MC1R activation on podocyte survival, antioxidant defense, and cytoskeleton dynamics were studied. To increase the response and enhance intracellular signals, podocytes were transduced to overexpress MC1R. We showed that puromycin promotes MC1R expression in podocytes and that activation of MC1R promotes an increase of catalase activity and reduces oxidative stress, which results in the dephosphorylation of p190RhoGAP and formation of stress fibers through RhoA. In addition, MC1R agonists protect against apoptosis. Together, these mechanisms protect the podocyte against puromycin. Our findings strongly support the hypothesis that selective MC1R-activating agonists protect podocytes and may therefore be useful to treat patients with nephrotic syndromes commonly considered as podocytopathies.
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Affiliation(s)
- Johannes Elvin
- Department of Molecular and Clinical Medicine, Institute of Medicine, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden;
| | - Lisa Buvall
- Department of Physiology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; and Department of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Annika Lindskog Jonsson
- Department of Molecular and Clinical Medicine, Institute of Medicine, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Anna Granqvist
- Department of Molecular and Clinical Medicine, Institute of Medicine, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Emelie Lassén
- Department of Molecular and Clinical Medicine, Institute of Medicine, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Lovisa Bergwall
- Department of Physiology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; and
| | - Jenny Nyström
- Department of Physiology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; and
| | - Börje Haraldsson
- Department of Molecular and Clinical Medicine, Institute of Medicine, the Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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60
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Abstract
Podocytes are highly specialized cells of the kidney glomerulus that wrap around capillaries and that neighbor cells of the Bowman’s capsule. When it comes to glomerular filtration, podocytes play an active role in preventing plasma proteins from entering the urinary ultrafiltrate by providing a barrier comprising filtration slits between foot processes, which in aggregate represent a dynamic network of cellular extensions. Foot processes interdigitate with foot processes from adjacent podocytes and form a network of narrow and rather uniform gaps. The fenestrated endothelial cells retain blood cells but permit passage of small solutes and an overlying basement membrane less permeable to macromolecules, in particular to albumin. The cytoskeletal dynamics and structural plasticity of podocytes as well as the signaling between each of these distinct layers are essential for an efficient glomerular filtration and thus for proper renal function. The genetic or acquired impairment of podocytes may lead to foot process effacement (podocyte fusion or retraction), a morphological hallmark of proteinuric renal diseases. Here, we briefly discuss aspects of a contemporary view of podocytes in glomerular filtration, the patterns of structural changes in podocytes associated with common glomerular diseases, and the current state of basic and clinical research.
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Affiliation(s)
- Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
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61
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XIE HUA, LIN HONGLI, WANG NAN, SUN YANLING, KAN YU, GUO HUI, CHEN JILIN, FANG MING. Inhibition of microRNA-30a prevents puromycin aminonucleoside-induced podocytic apoptosis by upregulating the glucocorticoid receptor α. Mol Med Rep 2015; 12:6043-52. [DOI: 10.3892/mmr.2015.4226] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 07/28/2015] [Indexed: 11/06/2022] Open
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62
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From Glomerular Endothelium to Podocyte Pathobiology in Preeclampsia: a Paradigm Shift. Curr Hypertens Rep 2015; 17:54. [DOI: 10.1007/s11906-015-0566-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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63
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Yoo TH, Fornoni A. Nonimmunologic targets of immunosuppressive agents in podocytes. Kidney Res Clin Pract 2015; 34:69-75. [PMID: 26484025 PMCID: PMC4570600 DOI: 10.1016/j.krcp.2015.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 03/16/2015] [Accepted: 03/21/2015] [Indexed: 02/06/2023] Open
Abstract
Proteinuria is a characteristic finding in glomerular diseases and is closely associated with renal outcomes. In addition, therapeutic interventions that reduce proteinuria improve renal prognosis. Accumulating evidence has demonstrated that podocytes act as key modulators of glomerular injury and proteinuria. The podocyte, or glomerular visceral epithelial cell, is a highly specialized and differentiated cell that forms interdigitated foot processes with neighboring podocytes, which are bridged together by an extracellular structure known as the "slit diaphragm" (SD). The SD acts as a size- and charge-selective barrier to plasma protein. Derangement of SD structure or loss of SD-associated protein results in podocyte injury and proteinuria. During the past decades, several immune-modulating agents have been used for the treatment of glomerular diseases and for the reduction of proteinuria. Interestingly, recent studies have demonstrated that immunosuppressive agents can have a direct effect on the SD-associated proteins and stabilize actin cytoskeleton in podocyte and have therefore introduced the concept of nonimmunologic mechanism of renoprotection by immunomodulators. This review focuses on the evidence that immuno-modulating agents directly target podocytes.
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Affiliation(s)
- Tae-Hyun Yoo
- Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Korea
- Division of Nephrology and Hypertension, Department of Medicine, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Alessia Fornoni
- Division of Nephrology and Hypertension, Department of Medicine, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
- Peggy and Harold Katz Family Drug Discovery Center, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
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64
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Levamisole in steroid-sensitive nephrotic syndrome: usefulness in adult patients and laboratory insights into mechanisms of action via direct action on the kidney podocyte. Clin Sci (Lond) 2015; 128:883-93. [PMID: 25626449 DOI: 10.1042/cs20140749] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Minimal change nephropathy (MCN) is the third most common cause of primary nephrotic syndrome in adults. Most patients with MCN respond to corticosteroid therapy, but relapse is common. In children, steroid-dependent patients are often given alternative agents to spare the use of steroids and to avoid the cumulative steroid toxicity. In this respect, levamisole has shown promise due to its ability to effectively maintain remission in children with steroid-sensitive or steroid-dependent nephrotic syndrome. Despite clinical effectiveness, there is a complete lack of molecular evidence to explain its mode of action and there are no published reports on the use of this compound in adult patients. We studied the effectiveness of levamisole in a small cohort of adult patients and also tested the hypothesis that levamisole's mode of action is attributable to its direct effects on podocytes. In the clinic, we demonstrate that in our adult patients, cohort levamisole is generally well tolerated and clinically useful. Using conditionally immortalized human podocytes, we show that levamisole is able to induce expression of glucocorticoid receptor (GR) and to activate GR signalling. Furthermore, levamisole is able to protect against podocyte injury in a puromycin aminonucleoside (PAN)-treated cell model. In this model the effects of levamisole are blocked by the GR antagonist mifepristone (RU486), suggesting that GR signalling is a critical target of levamisole's action. These results indicate that levamisole is effective in nephrotic syndrome in adults, as well as in children, and point to molecular mechanisms for this drug's actions in podocyte diseases.
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65
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Chaudhary K, Shinde R, Liu H, Gnana-Prakasam JP, Veeranan-Karmegam R, Huang L, Ravishankar B, Bradley J, Kvirkvelia N, McMenamin M, Xiao W, Kleven D, Mellor AL, Madaio MP, McGaha TL. Amino acid metabolism inhibits antibody-driven kidney injury by inducing autophagy. THE JOURNAL OF IMMUNOLOGY 2015; 194:5713-24. [PMID: 25980011 DOI: 10.4049/jimmunol.1500277] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 04/17/2015] [Indexed: 11/19/2022]
Abstract
Inflammatory kidney disease is a major clinical problem that can result in end-stage renal failure. In this article, we show that Ab-mediated inflammatory kidney injury and renal disease in a mouse nephrotoxic serum nephritis model was inhibited by amino acid metabolism and a protective autophagic response. The metabolic signal was driven by IFN-γ-mediated induction of indoleamine 2,3-dioxygenase 1 (IDO1) enzyme activity with subsequent activation of a stress response dependent on the eIF2α kinase general control nonderepressible 2 (GCN2). Activation of GCN2 suppressed proinflammatory cytokine production in glomeruli and reduced macrophage recruitment to the kidney during the incipient stage of Ab-induced glomerular inflammation. Further, inhibition of autophagy or genetic ablation of Ido1 or Gcn2 converted Ab-induced, self-limiting nephritis to fatal end-stage renal disease. Conversely, increasing kidney IDO1 activity or treating mice with a GCN2 agonist induced autophagy and protected mice from nephritic kidney damage. Finally, kidney tissue from patients with Ab-driven nephropathy showed increased IDO1 abundance and stress gene expression. Thus, these findings support the hypothesis that the IDO-GCN2 pathway in glomerular stromal cells is a critical negative feedback mechanism that limits inflammatory renal pathologic changes by inducing autophagy.
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Affiliation(s)
- Kapil Chaudhary
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912
| | - Rahul Shinde
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912
| | - Haiyun Liu
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912
| | - Jaya P Gnana-Prakasam
- Signaling and Angiogenesis Program, Georgia Regents University Cancer Center, Augusta, GA 30912
| | | | - Lei Huang
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912; Department of Radiology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912
| | - Buvana Ravishankar
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912
| | - Jillian Bradley
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912
| | - Nino Kvirkvelia
- Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912; and
| | - Malgorzata McMenamin
- Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912; and
| | - Wei Xiao
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912
| | - Daniel Kleven
- Department of Pathology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912
| | - Andrew L Mellor
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912; Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912; and
| | - Michael P Madaio
- Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912; and
| | - Tracy L McGaha
- Cancer Immunology, Inflammation, and Tolerance Program, Georgia Regents University Cancer Center, Augusta, GA 30912; Department of Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912; and
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Fukuda R, Suico MA, Kai Y, Omachi K, Motomura K, Koga T, Komohara Y, Koyama K, Yokota T, Taura M, Shuto T, Kai H. Podocyte p53 Limits the Severity of Experimental Alport Syndrome. J Am Soc Nephrol 2015; 27:144-57. [PMID: 25967122 DOI: 10.1681/asn.2014111109] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/26/2015] [Indexed: 11/03/2022] Open
Abstract
Alport syndrome (AS) is one of the most common types of inherited nephritis caused by mutation in one of the glomerular basement membrane components. AS is characterized by proteinuria at early stage of the disease and glomerular hyperplastic phenotype and renal fibrosis at late stage. Here, we show that global deficiency of tumor suppressor p53 significantly accelerated AS progression in X-linked AS mice and decreased the lifespan of these mice. p53 protein expression was detected in 21-week-old wild-type mice but not in age-matched AS mice. Expression of proinflammatory cytokines and profibrotic genes was higher in p53(+/-) AS mice than in p53(+/+) AS mice. In vitro experiments revealed that p53 modulates podocyte migration and positively regulates the expression of podocyte-specific genes. We established podocyte-specific p53 (pod-p53)-deficient AS mice, and determined that pod-p53 deficiency enhanced the AS-induced renal dysfunction, foot process effacement, and alteration of gene-expression pattern in glomeruli. These results reveal a protective role of p53 in the progression of AS and in maintaining glomerular homeostasis by modulating the hyperplastic phenotype of podocytes in AS.
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Affiliation(s)
- Ryosuke Fukuda
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Mary Ann Suico
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yukari Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kohei Omachi
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Keishi Motomura
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Tomoaki Koga
- Department of Biochemistry, Juntendo University School of Medicine, Tokyo, Japan; and
| | - Yoshihiro Komohara
- Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kosuke Koyama
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Tsubasa Yokota
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Manabu Taura
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Tsuyoshi Shuto
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Hirofumi Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan;
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67
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Lee HW, Khan SQ, Faridi MH, Wei C, Tardi NJ, Altintas MM, Elshabrawy HA, Mangos S, Quick KL, Sever S, Reiser J, Gupta V. A Podocyte-Based Automated Screening Assay Identifies Protective Small Molecules. J Am Soc Nephrol 2015; 26:2741-52. [PMID: 25858967 DOI: 10.1681/asn.2014090859] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 01/08/2015] [Indexed: 12/30/2022] Open
Abstract
Podocyte injury and loss mark an early step in the pathogenesis of various glomerular diseases, making these cells excellent targets for therapeutics. However, cell-based high-throughput screening assays for the rational development of podocyte-directed therapeutics are currently lacking. Here, we describe a novel high-content screening-based phenotypic assay that analyzes thousands of podocytes per assay condition in 96-well plates to quantitatively measure dose-dependent changes in multiple cellular features. Our assay consistently produced a Z' value >0.44, making it suitable for compound screening. On screening with >2100 pharmacologically active agents, we identified 24 small molecules that protected podocytes against injury in vitro (1% hit rate). Among the identified hits, we confirmed an β1-integrin agonist, pyrintegrin, as a podocyte-protective agent. Treatment with pyrintegrin prevented damage-induced decreases in F-actin stress fibers, focal adhesions, and active β1-integrin levels in cultured cells. In vivo, administration of pyrintegrin protected mice from LPS-induced podocyte foot process effacement and proteinuria. Analysis of the murine glomeruli showed that LPS administration reduced the levels of active β1 integrin in the podocytes, which was prevented by cotreatment with pyrintegrin. In rats, pyrintegrin reduced peak proteinuria caused by puromycin aminonucleoside-induced nephropathy. Our findings identify pyrintegrin as a potential therapeutic candidate and show the use of podocyte-based screening assays for identifying novel therapeutics for proteinuric kidney diseases.
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Affiliation(s)
- Ha Won Lee
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Samia Q Khan
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Mohd Hafeez Faridi
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Changli Wei
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Nicholas J Tardi
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Hatem A Elshabrawy
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Steve Mangos
- Department of Medicine, Rush University Medical Center, Chicago, Illinois
| | - Kevin L Quick
- Cellular Imaging and Analysis, PerkinElmer Life Sciences, Waltham, Massachusetts; and
| | - Sanja Sever
- Department of Medicine, Harvard Medical School, Division of Nephrology, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, Illinois;
| | - Vineet Gupta
- Department of Medicine, Rush University Medical Center, Chicago, Illinois;
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68
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Yang X, Wu X, Wu K, Yang D, Li Y, Shi J, Liu Y. Correlation of serum- and glucocorticoid-regulated kinase 1 expression with ischemia-reperfusion injury after heart transplantation. Pediatr Transplant 2015; 19:196-205. [PMID: 25515054 DOI: 10.1111/petr.12417] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/25/2014] [Indexed: 01/19/2023]
Abstract
IRI of a transplanted heart may result in serious early and late disadvantageous effects such as increased allograft immunogenicity, primary graft dysfunction, and initiation of fibroproliferative cascades that compromise the survival of the recipient. Sgk-1 has recently been linked to cell growth and survival. It has been reported that through a renal transplantation model, Dexa increases Sgk-1 expression and therefore protects from renal IRI. In our current study, we aim to assess the expression of Sgk-1 and its protective effects on cardiomyocyte IRI after heart transplantation. Heart allograft model was performed from Wistar into Lewis, and isograft model was from Lewis into Lewis. Grafts were then harvested at one, six, 12, or 24 h post-transplantation for Sgk-1 expression analyses. In some groups, part donors were treated with Dexa 2 h prior at doses of 0.05, 0.5 and 2 mg/BWkg, respectively. Sgk-1 expression was markedly increased in grafted heart 6-12 h post-transplantation in both the allogenic and isogenic models. Immunostaining experiments confirmed that Sgk-1 was expressed in cardiomyocytes rather than infiltrated immune cells. Furthermore, Dexa treatment significantly increased Sgk-1 expression and the donor cardiomyocyte injury was greatly minimized by Dexa treatment. These results suggest that induction of Sgk-1 might explain some of the beneficial impact of corticosteroids in IRI and hence might have therapeutic implications.
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Affiliation(s)
- Xuechao Yang
- Department of Cardiothoracic Surgery, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China
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69
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Shengyou Y, Li Y, Zhihong H, Yuanyuan M. Influence of tacrolimus on podocyte injury inducted by angiotensin II. J Renin Angiotensin Aldosterone Syst 2015; 16:260-6. [PMID: 25650384 DOI: 10.1177/1470320314568520] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/10/2014] [Indexed: 11/16/2022] Open
Affiliation(s)
- Yu Shengyou
- Department of Pediatric, Guangzhou First People’s Hospital, Guangzhou Medical University, China
| | - Yu Li
- Department of Pediatric, Guangzhou First People’s Hospital, Guangzhou Medical University, China
| | - Hao Zhihong
- Department of Pediatric, Guangzhou First People’s Hospital, Guangzhou Medical University, China
| | - Ma Yuanyuan
- Department of Pediatric, Guangzhou First People’s Hospital, Guangzhou Medical University, China
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70
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Small molecule membrane transporters in the mammalian podocyte: a pathogenic and therapeutic target. Int J Mol Sci 2014; 15:21366-80. [PMID: 25411800 PMCID: PMC4264230 DOI: 10.3390/ijms151121366] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/06/2014] [Accepted: 11/13/2014] [Indexed: 01/10/2023] Open
Abstract
The intriguingly complex glomerular podocyte has been a recent object of intense study. Researchers have sought to understand its role in the pathogenesis of common proteinuric diseases such as minimal change disease and focal segmental glomerular sclerosis. In particular, considerable effort has been directed towards the anatomic and functional barrier to macromolecular filtration provided by the secondary foot processes, but little attention has been paid to the potential of podocytes to handle plasma proteins beyond the specialization of the slit diaphragm. Renal membrane transporters in the proximal tubule have been extensively studied for decades, particularly in relation to drug metabolism and elimination. Recently, uptake and efflux transporters for small organic molecules have also been found in the glomerular podocyte, and we and others have found that these transporters can engage not only common pharmaceuticals but also injurious endogenous and exogenous agents. We have also found that the activity of podocyte transporters can be manipulated to inhibit pathogen uptake and efflux. It is conceivable that podocyte transporters may play a role in disease pathogenesis and may be a target for future drug development.
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71
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Inhibition of p53 deSUMOylation exacerbates puromycin aminonucleoside-induced apoptosis in podocytes. Int J Mol Sci 2014; 15:21314-30. [PMID: 25411797 PMCID: PMC4264227 DOI: 10.3390/ijms151121314] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/04/2014] [Accepted: 11/05/2014] [Indexed: 11/17/2022] Open
Abstract
Apoptosis is a major cause of reduced podocyte numbers, which leads to proteinuria and/or glomerulosclerosis. Emerging evidence has indicated that deSUMOylation, a dynamic post-translational modification that reverses SUMOylation, is involved in the apoptosis of Burkitt’s lymphoma cells and cardiomyocytes; however, the impact of deSUMOylation on podocyte apoptosis remains unexplored. The p53 protein plays a major role in the pathogenesis of podocyte apoptosis, and p53 can be SUMOylated. Therefore, in the present study, we evaluated the effect of p53 deSUMOylation, which is regulated by sentrin/SUMO-specific protease 1 (SENP1), on podocyte apoptosis. Our results showed that SENP1 deficiency significantly increases puromycin aminonucleoside (PAN)-induced podocyte apoptosis. Moreover, SENP1 knockdown results in the accumulation of SUMOylated p53 protein and the increased expression of the p53 target pro-apoptotic genes, BAX, Noxa and PUMA, in podocytes during PAN stimulation. Thus, SENP1 may be essential for preventing podocyte apoptosis, at least partly through regulating the functions of p53 protein via deSUMOylation. The regulation of deSUMOylation may provide a novel strategy for the treatment of glomerular disorders that involve podocyte apoptosis.
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72
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The effects of dexamethasone on the proliferation and apoptosis of human ovarian cancer cells induced by paclitaxel. J Ovarian Res 2014; 7:89. [PMID: 25297825 PMCID: PMC4200216 DOI: 10.1186/s13048-014-0089-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/31/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dexamethasone (DEX) has been routinely used as a pre-treatment in the clinical application of paclitaxel (PTX) to treat ovarian cancer. However, PTX-induced apoptosis might be inhibited by DEX. This study was undertaken to investigate the effects of DEX on the apoptosis induced by PTX. METHODS Both of SKOV-3 and HO-8910 human ovarian cancer cells were divided into four groups: (1) untreated (Con); (2) treated with DEX (0.1 μM) alone; (3) treated with PTX (50 nM); and (4) pre-treated with DEX (0.1 μM), and 24 h later, treated with PTX (DEX + PTX). Cell proliferation was determined by the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) dye uptake method, while cell apoptosis was analyzed by propidium iodide (PI) staining and flow cytometry. Then, reverse transcription polymerase chain reactions (RT-PCRs) were applied to semi-quantitative analysis, followed by western blot analysis. Statistical analysis was performed, with Fisher's least significant difference test. RESULTS Our results demonstrated that DEX can differentially inhibit SKOV-3 and HO-8910 cell proliferation induced by PTX and decrease the apoptosis rates in cancer cells. Pre-treatment with DEX could up-regulate the expressions of members of anti-apoptotic Bcl-2 family (Bcl-2 and Bcl-XL) and members of IAP family (survivin). The expression of cleaved caspase-3 was down-regulated by DEX, shown by semi-quantitative RT-PCRs and western blot analysis. CONCLUSIONS Our data gained invaluable insights of the antagonistic mechanisms of DEX on PTX-induced cancer cell death and may provide new methods of using DEX as antineoplastic drugs or agents in the clinical treatment for ovarian cancer patients.
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73
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Shengyou Y, Li Y. The effects of siRNA-silenced TRPC6 on podocyte autophagy and apoptosis induced by AngII. J Renin Angiotensin Aldosterone Syst 2014; 16:1266-73. [PMID: 25143325 DOI: 10.1177/1470320314543724] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Yu Shengyou
- Department of Pediatrics, Guangzhou First People’s Hospital, affiliate to Guangzhou Medical University, China
| | - Yu Li
- Department of Pediatrics, Guangzhou First People’s Hospital, affiliate to Guangzhou Medical University, China
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74
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Albumin-induced podocyte injury and protection are associated with regulation of COX-2. Kidney Int 2014; 86:1150-60. [PMID: 24918154 PMCID: PMC4245399 DOI: 10.1038/ki.2014.196] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 03/26/2014] [Accepted: 04/03/2014] [Indexed: 01/11/2023]
Abstract
Albuminuria is both a hallmark and a risk factor for progressive glomerular disease, and results in increased exposure of podocytes to serum albumin with its associated factors. Here in vivo and in vitro models of serum albumin overload were used to test the hypothesis that albumin-induced proteinuria and podocyte injury directly correlate with COX-2 induction. Albumin induced COX-2, MCP-1, CXCL1 and the stress protein HSP25 in both rat glomeruli and cultured podocytes, while B7-1 and HSP70i were also induced in podocytes. Podocyte exposure to albumin induced both mRNA and protein and enhanced the mRNA stability of COX-2, a key regulator of renal hemodynamics and inflammation, which renders podocytes susceptible to injury. Podocyte exposure to albumin also stimulated several kinases (p38 MAPK, MK2, JNK/SAPK and ERK1/2), inhibitors of which (except JNK/SAPK) down-regulated albumin-induced COX-2. Inhibition of AMPK, PKC and NFκB also down-regulated albumin-induced COX-2. Critically, albumin-induced COX-2 was also inhibited by glucocorticoids and thiazolidinediones, both of which directly protect podocytes against injury. Furthermore, specific albumin-associated fatty acids were identified as important contributors to COX-2 induction, podocyte injury and proteinuria. Thus, COX-2 is associated with podocyte injury during albuminuria, as well as with the known podocyte protection imparted by glucocorticoids and thiazolidinediones. Moreover, COX-2 induction, podocyte damage and albuminuria appear mediated largely by serum albumin-associated fatty acids.
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75
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Lan A, Du J. Potential role of Akt signaling in chronic kidney disease. Nephrol Dial Transplant 2014; 30:385-94. [PMID: 24891436 DOI: 10.1093/ndt/gfu196] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Renal fibrosis, particularly tubulointerstitial fibrosis, is the common final outcome of almost all chronic kidney diseases. However, the mechanisms involved in the development of renal fibrosis are poorly understood. The Akt (also known as protein kinase B, PKB) family is serine/threonine protein kinases that play critical roles in regulating growth, proliferation, survival, metabolism and other cellular activities. Cytokines, high-glucose medium, transforming growth factor-β1 or advanced glycation end-products activate Akt in different renal cells. Increased Akt activation has been found in experimental tubulointerstitial fibrosis. In addition, Akt activation is also an important node in diverse signaling cascades involved in kidney damage. These data give evidence for a role for Akt in renal fibrosis, but no reviews are available on the role of Akt in the process. Thus, our aim is to review the role of Akt activation and signaling in renal fibrosis.
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Affiliation(s)
- Aiping Lan
- The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing An Zhen Hospital, Institute of Heart Lung and Blood Vessel Diseases, Capital Medical University, Beijing 100029, China
| | - Jie Du
- The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing An Zhen Hospital, Institute of Heart Lung and Blood Vessel Diseases, Capital Medical University, Beijing 100029, China
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76
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Ischemic preconditioning enhances autophagy but suppresses autophagic cell death in rat spinal neurons following ischemia-reperfusion. Brain Res 2014; 1562:76-86. [DOI: 10.1016/j.brainres.2014.03.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 02/07/2014] [Accepted: 03/17/2014] [Indexed: 02/05/2023]
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77
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Li X, Zhang X, Li X, Ding F, Ding J. The role of survivin in podocyte injury induced by puromycin aminonucleoside. Int J Mol Sci 2014; 15:6657-73. [PMID: 24747598 PMCID: PMC4013653 DOI: 10.3390/ijms15046657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 04/04/2014] [Accepted: 04/08/2014] [Indexed: 11/29/2022] Open
Abstract
Objective Survivin is a member of the inhibitor of apoptosis protein family, which uniquely promotes mitosis and regulates apoptosis in cancer cells. Recent studies have demonstrated that survivin also expresses in several normal adult cells. In the present study, we aimed to investigate the function of survivin in the terminally differentiated epithelial cells, podocytes. Methods Survivin expression and location were detected by Quantitative Real-Time PCR, western blot and fluorescence confocal microscopy methods in normal and injured mouse podocytes. Cyto-protection function of survivin was also studied in cultured podocyte injured by puromycin aminonucleoside (PAN), transfected with survivin siRNA to down-regulate survivin expression, or with survivin plasmid to transiently over-express survivin. Results In podocytes, PAN stimulated expressions of survivin and the apoptosis related molecule caspase 3. Knockdown of survivin expression by siRNA increased the activation of caspase 3, induced podocyte apoptosis and remarkable rearrangement of actin cytoskeleton. Moreover, over-expression of survivin inhibited PAN-induced podocyte apoptosis and cytoskeleton rearrangement. Conclusion Our data provides the evidence that survivin plays an important role in protecting podocytes from apoptosis induced by PAN. The mechanism of survivin related anti-apoptosis may, at least partially, be through the activation of caspase 3.
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Affiliation(s)
- Xuejuan Li
- Department of Pediatrics, Peking University First Hospital, No.1 Xi An Men Da Jie, Beijing 100034, China.
| | - Xiaoyan Zhang
- Department of Pediatrics, Peking University First Hospital, No.1 Xi An Men Da Jie, Beijing 100034, China.
| | - Xiaoyan Li
- Department of Pediatrics, Peking University First Hospital, No.1 Xi An Men Da Jie, Beijing 100034, China.
| | - Fangrui Ding
- Department of Pediatrics, Peking University First Hospital, No.1 Xi An Men Da Jie, Beijing 100034, China.
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, No.1 Xi An Men Da Jie, Beijing 100034, China.
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78
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The cytoprotective role of autophagy in puromycin aminonucleoside treated human podocytes. Biochem Biophys Res Commun 2014; 443:628-34. [DOI: 10.1016/j.bbrc.2013.12.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 12/03/2013] [Indexed: 02/06/2023]
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79
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Canaud G, Dejucq-Rainsford N, Avettand-Fenoël V, Viard JP, Anglicheau D, Bienaimé F, Muorah M, Galmiche L, Gribouval O, Noël LH, Satie AP, Martinez F, Sberro-Soussan R, Scemla A, Gubler MC, Friedlander G, Antignac C, Timsit MO, Onetti Muda A, Terzi F, Rouzioux C, Legendre C. The kidney as a reservoir for HIV-1 after renal transplantation. J Am Soc Nephrol 2013; 25:407-19. [PMID: 24309185 DOI: 10.1681/asn.2013050564] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Since the recent publication of data showing favorable outcomes for patients with HIV-1 and ESRD, kidney transplantation has become a therapeutic option in this population. However, reports have documented unexplained reduced allograft survival in these patients. We hypothesized that the unrecognized infection of the transplanted kidney by HIV-1 can compromise long-term allograft function. Using electron microscopy and molecular biology, we examined protocol renal transplant biopsies from 19 recipients with HIV-1 who did not have detectable levels of plasma HIV-1 RNA at transplantation. We found that HIV-1 infected the kidney allograft in 68% of these patients. Notably, HIV-1 infection was detected in either podocytes predominately (38% of recipients) or tubular cells only (62% of recipients). Podocyte infection associated with podocyte apoptosis and loss of differentiation markers as well as a faster decline in allograft function compared with tubular cell infection. In allografts with tubular cell infection, epithelial cells of the proximal convoluted tubules frequently contained abnormal mitochondria, and both patients who developed features of subclinical acute cellular rejection had allografts with tubular cell infection. Finally, we provide a novel noninvasive test for determining HIV-1 infection of the kidney allograft by measuring HIV-1 DNA and RNA levels in patients' urine. In conclusion, HIV-1 can infect kidney allografts after transplantation despite undetectable viremia, and this infection might influence graft outcome.
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Affiliation(s)
- Guillaume Canaud
- Institut National de la Santé et de la Recherche Médicale U845, Growth and Signaling Research Center, Paris Descartes University, Necker Hospital, Paris, France
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Wu J, Zheng C, Fan Y, Zeng C, Chen Z, Qin W, Zhang C, Zhang W, Wang X, Zhu X, Zhang M, Zen K, Liu Z. Downregulation of microRNA-30 facilitates podocyte injury and is prevented by glucocorticoids. J Am Soc Nephrol 2013; 25:92-104. [PMID: 24029422 DOI: 10.1681/asn.2012111101] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
MicroRNAs (miRNAs) are essential for podocyte homeostasis, and the miR-30 family may be responsible for this action. However, the exact roles and clinical relevance of miR-30s remain unknown. In this study, we examined the expression of the miR-30 family in the podocytes of patients with FSGS and found that all members are downregulated. Treating cultured human podocytes with TGF-β, LPS, or puromycin aminonucleoside (PAN) also downregulated the miR-30 family. Podocyte cytoskeletal damage and apoptosis caused by treatment with TGF-β or PAN were ameliorated by exogenous miR-30 expression and aggravated by miR-30 knockdown. Moreover, we found that miR-30s exert their protective roles by direct inhibition of Notch1 and p53, which mediate podocyte injury. In rats, treatment with PAN substantially downregulated podocyte miR-30s and induced proteinuria and podocyte injury; however, transfer of exogenous miR-30a to podocytes of PAN-treated rats ameliorated proteinuria and podocyte injury and reduced Notch1 activation. Finally, we demonstrated that glucocorticoid treatment maintains miR-30 expression in cultured podocytes treated with TGF-β, LPS, or PAN and in the podocytes of PAN-treated rats. Glucocorticoid-sustained miR-30 expression associated with reduced Notch1 activation and alleviated podocyte damage. Taken together, these findings demonstrate that miR-30s protect podocytes by targeting Notch1 and p53 and that the loss of miR-30s facilitates podocyte injury. In addition, sustained miR-30 expression may be a novel mechanism underlying the therapeutic effectiveness of glucocorticoids in treating podocytopathy.
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Affiliation(s)
- Junnan Wu
- Research Institute of Nephrology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu, China
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81
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Hassanpour M, Joss J, Mohammad MG. Functional analyses of lymphocytes and granulocytes isolated from the thymus, spiral valve intestine, spleen, and kidney of juvenile Australian lungfish, Neoceratodus forsteri. FISH & SHELLFISH IMMUNOLOGY 2013; 35:107-114. [PMID: 23603235 DOI: 10.1016/j.fsi.2013.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 03/12/2013] [Accepted: 04/04/2013] [Indexed: 06/02/2023]
Abstract
Our current understanding of the lungfish immune system is limited. This study is characterizing the immune cells separated from primary and secondary immune organs of the Australian lungfish, Neoceratodus forsteri. Our functional studies utilized flow cytometry to study the immune cells extracted from the thymus, spiral valve intestine, spleen, and kidney. The different characteristics of lymphocytes and granulocytes were analyzed by utilization of viability, phagocytosis, oxidative burst, and apoptosis assays. Most of the nonviable intestinal cells were lymphocytes. Depending on the organ, 6-25% of the total population, predominantly granulocytes, underwent phagocytosis where the splenic cells were the most and intestinal cells the least phagocytic cells. Cells responded positively but differently to stimulation with phorbol myristate acetate (PMA) to produce radical oxygen species, an indication of their oxidative burst activity, which was mainly associated with granulocytes. Although cells were induced by dexamethasone to undergo apoptosis, such an induction did not follow a consistent pattern of dose of dexamethasone or incubation time between the different organs. In the absence of monoclonal antibodies against lungfish immune cells, these functional flow cytometric analyses aid our understanding on the functionality of immune cells.
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Affiliation(s)
- Masoud Hassanpour
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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82
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Rusai K, Prokai A, Juanxing C, Meszaros K, Szalay B, Pásti K, Müller V, Heemann U, Lutz J, Tulassay T, Szabo A. Dexamethasone protects from renal ischemia/reperfusion injury: A possible association with SGK-1. ACTA ACUST UNITED AC 2013; 100:173-85. [DOI: 10.1556/aphysiol.100.2013.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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83
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Long DA, Kolatsi-Joannou M, Price KL, Dessapt-Baradez C, Huang JL, Papakrivopoulou E, Hubank M, Korstanje R, Gnudi L, Woolf AS. Albuminuria is associated with too few glomeruli and too much testosterone. Kidney Int 2013; 83:1118-29. [PMID: 23447063 PMCID: PMC3674403 DOI: 10.1038/ki.2013.45] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 12/15/2012] [Accepted: 12/21/2012] [Indexed: 12/12/2022]
Abstract
Normally, the glomerular filtration barrier almost completely excludes circulating albumin from entering the urine. Genetic variation and both pre- and postnatal environmental factors may affect albuminuria in humans. Here we determine whether glomerular gene expression in mouse strains with naturally occurring variations in albuminuria would allow identification of proteins deregulated in relatively 'leaky' glomeruli. Albuminuria increased in female B6 to male B6 to female FVB/N to male FVB/N mice, whereas the number of glomeruli/kidney was the exact opposite. Testosterone administration led to increased albuminuria in female B6 but not female FVB/N mice. A common set of 39 genes, many expressed in podocytes, were significantly differentially expressed in each of the four comparisons: male versus female B6 mice, male versus female FVB/N mice, male FVB/N versus male B6 mice, and female FVB/N versus female B6 mice. The transcripts encoded proteins involved in oxidation/reduction reactions, ion transport, and enzymes involved in detoxification. These proteins may represent novel biomarkers and even therapeutic targets for early kidney and cardiovascular disease.
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Affiliation(s)
- David A Long
- Nephro-Urology Unit, UCL Institute of Child Health, London, UK.
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84
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Choi HM, Jo SK, Kim SH, Lee JW, Cho E, Hyun YY, Cha JJ, Kang YS, Cha DR, Cho WY, Kim HK. Glucocorticoids attenuate septic acute kidney injury. Biochem Biophys Res Commun 2013; 435:678-84. [PMID: 23702481 DOI: 10.1016/j.bbrc.2013.05.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 05/10/2013] [Indexed: 11/26/2022]
Abstract
BACKGROUND The incidence and mortality of septic acute kidney injury (AKI) remains high, whereas our understanding of pathogenesis for septic AKI is still limited. Glucocorticoids (GCs) have been clinically recommended for treatment of septic shock and also have showed favorable effect on septic AKI in several animal experiments. The aim of this study is to investigate the pathophysiology of septic AKI and the effect of GCs on septic AKI. METHODS We induced septic AKI using cecal ligation and puncture (CLP) model in 8-10 wk-old male C57BL/6 mice. Saline or dexamethasone (2.5 mg/kg) dissolved in saline was administered after surgery. Hemodynamic, biochemical and histological changes were examined in a time-course manner. RESULTS CLP resulted in hyperdynamic warm shock with multiple organ dysfunction including AKI. Despite renal dysfunction, light microscopy showed scanty acute tubular necrosis and inflammation. Instead, CLP induced significant increase in apoptosis of the kidney and spleen cells. In addition, septic kidneys showed mitochondrial injury and alterations in Bcl2 family proteins in the renal tubular cells. Dexamethasone treatment attenuated renal dysfunction, but it was not associated with improvement of hemodynamic parameters. Dexamethasone-induced organ protective effect was associated with reduced mitochondrial injury with preserved cytochrome c oxidase and suppression of proapoptotic proteins as well as reduced cytokine release. CONCLUSIONS Mitochondrial damage and subsequent apoptosis are thought to play important role in the development of septic AKI. GCs might be a useful therapeutic strategy for septic AKI by reducing mitochondrial damage and apoptosis.
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Affiliation(s)
- Hye Min Choi
- Division of Nephrology, Department of Internal Medicine, Korea University Medical College, Seoul, Republic of Korea
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85
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Dexamethasone inhibits podocyte apoptosis by stabilizing the PI3K/Akt signal pathway. BIOMED RESEARCH INTERNATIONAL 2013; 2013:326986. [PMID: 23710442 PMCID: PMC3655450 DOI: 10.1155/2013/326986] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 03/16/2013] [Accepted: 03/28/2013] [Indexed: 02/01/2023]
Abstract
Corticosteroids like dexamethasone (DEX) are well-established treatments for the glomerular disease that sustain renal function, at least in part, by protecting podocytes from apoptotic death. In this study, we found that PAN causes abnormal expression of the PI3K-binding protein CD2AP, reducing PI3K/Akt signaling and promoting podocyte apoptosis. In contrast, DEX restores CD2AP-PI3K-Akt-GSK3 β signaling, which promotes the activity of antiapoptotic proteins and inhibits the activity of proapoptotic proteins. In addition, we also found that CD2AP was aberrantly colocalized with p85. Normal CD2AP mRNA expression and subcellular protein distribution were maintained in the PAN + DEX group, and DEX coapplication also reduced CD2AP-p85 colocalization. PAN evoked a concentration-dependent decrease in p-Akt and p-GSK3 β expressions, with p-Akt expression reaching a nadir at 15 min and p-GSK3 β expression at 30 min. DEX treatment induced a concentration-dependent reversal of PAN-induced p-Akt and p-GSK3 β downregulation. The PI3K inhibitor LY294002 blocked p-Akt and p-GSK3 β expressions in podocytes. Cells treated with PAN exhibited a significantly higher apoptosis rate than untreated or vehicle-treated cells. Furthermore, LY294002 exacerbated PAN-induced apoptosis. DEX cotreatment caused a significant concentration-dependent decrease in PAN-induced apoptosis. These results strongly suggest that DEX protects podocytes by stabilizing the expression and subcellular distribution of CD2AP and by maintaining the expression of phosphor-activated Akt and GSK3β .
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86
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Gruver-Yates AL, Cidlowski JA. Tissue-specific actions of glucocorticoids on apoptosis: a double-edged sword. Cells 2013; 2:202-23. [PMID: 24709697 PMCID: PMC3972684 DOI: 10.3390/cells2020202] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/05/2013] [Accepted: 03/12/2013] [Indexed: 12/20/2022] Open
Abstract
First described for their metabolic and immunosuppressive effects, glucocorticoids are widely prescribed in clinical settings of inflammation. However, glucocorticoids are also potent inducers of apoptosis in many cell types and tissues. This review will focus on the established mechanisms of glucocorticoid-induced apoptosis and outline what is known about the apoptotic response in cells and tissues of the body after exposure to glucocorticoids. Glucocorticoid-induced apoptosis affects the skeletal system, muscular system, circulatory system, nervous system, endocrine system, reproductive system, and the immune system. Interestingly, several cell types have an anti-apoptotic response to glucocorticoids that is cytoprotective. Lastly, we will discuss the pro- and anti-apoptotic effects of glucocorticoids in cancers and their clinical implications.
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Affiliation(s)
- Amanda L Gruver-Yates
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
| | - John A Cidlowski
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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87
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c-Abl mediates angiotensin II-induced apoptosis in podocytes. J Mol Histol 2013; 44:597-608. [PMID: 23515840 DOI: 10.1007/s10735-013-9505-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 03/14/2013] [Indexed: 10/27/2022]
Abstract
Angiotensin II (Ang II) has been reported to cause podocyte apoptosis in rats both in vivo and in vitro studies. However, the underlying mechanisms are poorly understood. In the present study, we investigated the role of the nonreceptor tyrosine kinase c-Abl in Ang II-induced podocyte apoptosis. Male Sprague-Dawley rats in groups of 12 were administered either Ang II (400 kg/kg/min) or Ang II + STI-571 (50 mg/kg/day) by osmotic minipumps. In addition, 12 rats-receiving normal saline served as the control. Glomeruli c-Abl expression was carried out by real time PCR, Western blotting and immunolabeled, and occurrence of apoptosis was carried out by TUNEL staining and transmission electron microscopic analysis. In vitro studies, conditionally immortalized mouse podocytes were treated with Ang II (10(-9)-10(-6) M) in the presence or absence of either c-Abl inhibitor, Src-I1, specific c-Abl siRNA, or c-Abl plasmid alone. Quantification of podocyte c-Abl expression and c-Abl phosphorylation at Y245 and Y412 was carried out by real time PCR, Western blotting and immunofluorescence imaging. The nuclear c-Abl and p53 were quantified by co-immunoprecipitation and Western blotting studies. Podocyte apoptosis was analysed by flow cytometry and Hoechst-33342 staining. c-Abl expression was demonstrated in rat kidney podocytes in vivo and cultured mouse podocytes in vitro. Ang II-receiving rats displayed enhanced podocyte c-Abl expression. And Ang II significantly stimulated c-Abl expression in cultured podocytes. Furthermore Ang II upregulated podocyte c-Abl phosphorylation at Y245 and Y412. Ang II also induced an increase of nuclear p53 protein and nuclear c-Abl-p53 complexes in podocytes and podocyte apoptosis. Down-regulation of c-Abl expression by c-Abl inhibitor (Src-I1) as well as specific siRNA inhibited Ang II-induced podocyte apoptosis; conversely, podoctyes transfected with c-Abl plasmid displayed enhanced apoptosis. These findings indicate that c-Abl may mediates Ang II-induced podocyte apoptosis, and inhibition of c-Abl expression can protect podocytes from Ang II-induced injury.
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88
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Zhang J, Pippin JW, Krofft RD, Naito S, Liu ZH, Shankland SJ. Podocyte repopulation by renal progenitor cells following glucocorticoids treatment in experimental FSGS. Am J Physiol Renal Physiol 2013; 304:F1375-89. [PMID: 23486009 DOI: 10.1152/ajprenal.00020.2013] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Prednisone is a mainstay of treatment for patients with focal segmental glomerulosclerosis (FSGS), a disease characterized by reduced podocyte number and glomerulosclerosis. Although the systemic immune-modulatory effects of prednisone are well-known, direct tissue effects on glomerular cells are poorly understood. Experimental FSGS was induced in mice with a cytotoxic anti-podocyte antibody, resulting in an abrupt decrease in podocyte number by day 3, proteinuria, and the development of glomerulosclerosis. Administering daily prednisone to mice with FSGS, beginning at day 3, significantly increased podocyte number at weeks 2 and 4. Podocyte number did not increase in control mice with FSGS given DMSO. The increase in podocyte number in prednisone-treated mice correlated significantly with reduced glomerulosclerosis. Prednisone reduced podocyte apoptosis measured by synaptopodin⁺/caspase-3⁺ double staining. Additionally, the number of podocyte progenitors, defined as cells expressing both a parietal epithelial cell protein and a podocyte protein, was significantly increased in prednisone-treated mice with FSGS at weeks 2 and 4. This was associated with increased phospho-ERK staining in both parietal epithelial cells (PAX2⁺/p-ERK⁺) and in podocyte progenitors (WT-1⁺/p-ERK⁺ lining Bowman's capsule). These data show that in this model of experimental FSGS, prednisone augments glomerular repair by increasing podocyte number through direct effects on both glomerular epithelial cells. Prednisone limits podocyte loss by reducing apoptosis, and it increases regeneration by augmenting the number of podocyte progenitors. The data support a direct glomerular cell action for prednisone in improving outcomes in FSGS.
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Affiliation(s)
- Jiong Zhang
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
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89
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Nagase M, Fujita T. Role of Rac1-mineralocorticoid-receptor signalling in renal and cardiac disease. Nat Rev Nephrol 2013; 9:86-98. [PMID: 23296296 DOI: 10.1038/nrneph.2012.282] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Rho-family small GTPase, Ras-related C3 botulinum toxin substrate 1 (Rac1), has been implicated in renal and cardiac disease. Rac1 activation in podocytes has been shown in several models of proteinuric kidney disease and a concept involving motile podocytes has been proposed. Evidence also exists for a critical role of Rac1-mediated oxidative stress in cardiac hypertrophy, cardiomyopathy and arrhythmia, and of the aldosterone-mineralocorticoid-receptor system in proteinuria and cardiac disorders. However, plasma aldosterone concentrations are not always increased in these conditions and the mechanisms of mineralocorticoid-receptor overactivation are difficult to determine. Using knockout mice, we identified a novel mechanism of Rac1-mediated podocyte impairment; Rac1 potentiates the activity of the mineralocorticoid receptor, thereby accelerating podocyte injury. We subsequently demonstrated that the Rac1-mineralocorticoid-receptor pathway contributes to ligand-independent mineralocorticoid-receptor activation in several animal models of kidney and cardiac injury. Hyperkalaemia is a major concern associated with the use of mineralocorticoid-receptor antagonists; however, agents that modulate the activity of the Rac1-mineralocorticoid-receptor pathway in target cells, such as cell-type-specific Rac inhibitors and selective mineralocorticoid-receptor modulators, could potentially be novel therapeutic candidates with high efficacy and a low risk of adverse effects in patients with renal and cardiac diseases.
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Affiliation(s)
- Miki Nagase
- Division of Chronic Kidney Disease, Department of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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90
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Che R, Zhang A. Mechanisms of Glucocorticoid Resistance in Idiopathic Nephrotic Syndrome. ACTA ACUST UNITED AC 2013; 37:360-78. [DOI: 10.1159/000350163] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2013] [Indexed: 11/19/2022]
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91
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Physiopathology of idiopathic nephrotic syndrome: lessons from glucocorticoids and epigenetic perspectives. Pediatr Nephrol 2012; 27:1249-56. [PMID: 21710250 DOI: 10.1007/s00467-011-1947-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/30/2011] [Accepted: 06/02/2011] [Indexed: 01/21/2023]
Abstract
Idiopathic nephrotic syndrome (INS) has been studied for decades in attempt to understand the physiopathological mechanisms explaining the disease. It is recognized as a multifactorial disease, with immunological components targeting kidney functions. Many hypotheses have been discussed or tested, including the role of a circulating factor, polymorphisms of genes implicated in lymphocyte maturation and differentiation, and DNA epigenetic modifications. In the present review, the data supporting these different (and probably combinatorial) hypotheses have been reviewed in order to identify and discuss the possible pathways implicated in the physiopathology of INS.
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92
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Ding WY, Saleem MA. Current concepts of the podocyte in nephrotic syndrome. Kidney Res Clin Pract 2012; 31:87-93. [PMID: 26889414 PMCID: PMC4715158 DOI: 10.1016/j.krcp.2012.04.323] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 04/09/2012] [Accepted: 04/12/2012] [Indexed: 01/08/2023] Open
Abstract
Nephrotic syndrome is a disorder of the glomerular filtration barrier, and central to the filtration mechanism of the glomerular filtration barrier is the podocyte. We are starting to better understand how this cell, with its unique architectural features, fulfils its exact filtration properties. The multiprotein complex between adjacent podocyte foot processes, the slit diaphragm, is essential to the control of the actin cytoskeleton and cell morphology. Many of the proteins within the slit diaphragm, including nephrin, podocin, transient receptor potential-6 channel, and α-actinin-4, have been identified via genetic studies of inherited nephrotic syndromes. Signaling from slit diaphragm proteins to the actin cytoskeleton is mediated via the Rho GTPases. These are thought to be involved in the control of podocyte motility, which has been postulated as a focus of proteinuric pathways. Nephrotic syndrome is currently treated with immunosuppressive therapy, with significant adverse effects. These therapies may work in nephrotic syndrome due to specific effects on the podocytes. This review aims to describe our current understanding of the cellular pathways and molecules within the podocyte relevant to nephrotic syndrome and its treatment. With our current knowledge of the cellular biology of the podocyte, there is much hope for targeted therapies for nephrotic syndromes.
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Affiliation(s)
- Wen Y Ding
- Academic Renal Unit, University of Bristol, Southmead Hospital, Bristol, UK
| | - Moin A Saleem
- Academic Renal Unit, University of Bristol, Southmead Hospital, Bristol, UK
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93
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Canaud G, Audard V, Kofman T, Lang P, Legendre C, Grimbert P. Recurrence from primary and secondary glomerulopathy after renal transplant. Transpl Int 2012; 25:812-24. [DOI: 10.1111/j.1432-2277.2012.01483.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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94
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Ory V, Fan Q, Hamdaoui N, Zhang SY, Desvaux D, Audard V, Candelier M, Noel LH, Lang P, Guellaën G, Pawlak A, Sahali D. c-mip down-regulates NF-κB activity and promotes apoptosis in podocytes. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:2284-92. [PMID: 22507836 DOI: 10.1016/j.ajpath.2012.02.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Revised: 01/28/2012] [Accepted: 02/07/2012] [Indexed: 11/26/2022]
Abstract
The mechanisms of podocyte disorders in cases of idiopathic nephrotic syndrome (INS) are complex and remain incompletely elucidated. The abnormal regulation of NF-κB may play a key role in the pathophysiology of these podocyte diseases, but at present, NF-κB has not been thoroughly investigated. In this study, we report that induction of c-mip in podocytes of patients with INS is associated with a down-regulation of RelA, a potent antiapoptotic factor that belongs to the NF-κB family. Overexpression of c-mip in differentiated podocytes promotes apoptosis by inducing caspase-3 activity and up-regulating the proapoptotic protein Bax, whereas the overall levels of the antiapoptotic protein Bcl-2 was concomitantly decreased. The associated overexpression of RelA prevented the proapoptotic effects of c-mip. In addition, the targeted induction of c-mip in podocytes in vivo inhibited the expression of the RelA protein and increased the Bax/Bcl-2 ratio. The expression of both c-mip and active caspase-3 increased in focal and segmental glomerulosclerosis biopsies, and both proteins displayed a close spatial relationship. These results suggest that alterations in NF-κB activity might result from the up-regulation of c-mip and are likely to contribute to podocyte disorders in cases of INS.
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95
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Dexamethasone Resisted Podocyte Injury via Stabilizing TRPC6 Expression and Distribution. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:652059. [PMID: 22545060 PMCID: PMC3321534 DOI: 10.1155/2012/652059] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 01/19/2012] [Indexed: 12/12/2022]
Abstract
TRPC6, a member of the canonical transient receptor potential channel (TRPC) subfamily, is an important cation selective ion channel on podocytes. Podocytes are highly differentiated cells located on the visceral face of glomerular basement membrane and featured by numerous foot processes, on which nephrin, podocin, and TRPC6 locate. Podocytes and the slit diaphragm (SD) between adjacent foot processes form a selective filtration barrier impermeable to proteins. TRPC6 is very critical for normal podocyte function. To investigate the function of TRPC6 in podocytes and its relation to proteinuria in kidney diseases, we over-expressed TRPC6 in podocytes by puromycin aminonucleoside (PAN) and observed the changes of foot processes, TRPC6 protein distribution, and mRNA expression. Accordingly, in this study, we further investigated the role of specific signaling mechanisms underlying the prosurvival effects of dexamethasone (DEX) on podocyte repair. Our results showed that podocytes processes of overexpressing TRPC6 were reduced remarkably. These changes could be rescued by DEX via blocking TRPC6 channel. Additionally, our results also showed an improvement in TRPC6 arrangement in the cells and decrease of mRNA expression and protein distribution. From these results, we therefore proposed that overexpression of TRPC6 in podocytes may be one of the fundamental changes relating to the dysfunction of the SD and proteinuria. DEX may be maintained the structure and function integrity of SD by blocking TRPC6 signal pathway and played an important role in mechanisms of anti-proteinuria.
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96
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Functional metabotropic glutamate receptors 1 and 5 are expressed in murine podocytes. Kidney Int 2011; 81:458-68. [PMID: 22166849 DOI: 10.1038/ki.2011.406] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In non-neuronal cells, glutamate is an extracellular signaling mediator. Since podocytes have glutamate-containing vesicles, we sought to determine glutamate receptor presence and action in glomerular cells. The metabotropic glutamate receptors (mGluR) 1, 5, 6, and 8 were found to be expressed in mouse brain and glomeruli; predominantly in podocytes. In two models of proteinuria (BalB/C mice with puromycin aminonucleoside- and doxorubicin-induced podocyte injury) we found that the selective mGluR1/5 agonist (S)-3,5-dihydroxyphenylglycine (DHPG) attenuated albuminuria and improved the expression of the podocyte marker WT-1. TUNEL staining showed that the number of podocytes undergoing apoptosis was inversely correlated with the number of WT-1-positive cells in glomeruli. When podocytes were treated with DHPG in vitro, they generated cyclic AMP and activated CREB (cyclic AMP response element binding protein). The selective mGluR1/5 antagonist (RS)-1-aminoindan-1,5-dicarboxylic acid, the adenylate cyclase inhibitor SQ22536, and RNA interference knockdown of mGluR1 or mGluR5 all prevented DHPG-induced cAMP generation and CREB activation. DHPG inhibited apoptosis and the decrease of aminonucleoside-induced mitochondrial membrane potential in podocytes but had no effect in the presence of SQ22536 with knockdown mGluR1 or mGluR5. Thus, functional mGluR1 and mGluR5 are expressed in podocytes and their activation protects against albuminuria and podocyte apoptosis, processes that are, at least in part, dependent on cAMP.
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98
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Wen D, You L, Zhang Q, Zhang L, Gu Y, Hao CM, Chen J. Upregulation of nestin protects podocytes from apoptosis induced by puromycin aminonucleoside. Am J Nephrol 2011; 34:423-34. [PMID: 21952051 DOI: 10.1159/000331701] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/12/2011] [Indexed: 01/12/2023]
Abstract
BACKGROUND Nestin is an intermediate filament protein widely used as a marker of stem cells or progenitor cells. Nestin is also highly expressed in the glomerular podocyte, a type of terminally differentiated epithelial cell. Little is known about the significance of nestin in podocytes. METHODS Puromycin aminonucleoside (PAN) was injected into the rats to produce a PAN nephrosis model. Transmission electronic microscopy and terminal dUTP nick end-labeling assay were used to examine the podocyte foot process (FP) effacement and apoptosis, respectively. A mouse podocyte cell line was cultured and incubated with PAN. Immunoblot was used to examine the level of nestin expression both in vivo and in vitro. Enhanced green fluorescence protein-tagged plasmids containing nestin shRNA were transfected into the cultured podocytes to silence nestin expression. F-actin arrangement within cultured podocytes was investigated by immunofluorescence, while the apoptosis rate was examined by both Hoechst stain and flow cytometry. RESULTS In the PAN-induced rat nephrosis model, podocyte nestin expression was increased in the absence of apparent podocyte apoptosis, even though the FP was significantly effaced. In the cultured mouse podocytes, PAN upregulated nestin expression in a time-dependent manner within 24 h of treatment. Notably, no significant apoptosis occurred, however knocking down nestin expression resulted in a remarkable derangement of actin cytoskeleton and an increase in apoptosis in the cultured podocytes 24 h after being incubated with PAN. CONCLUSIONS Upregulation of nestin expression during PAN nephrosis could protect podocytes from apoptosis and that this process is mediated by maintaining the regular arrangement of actin cytoskeleton.
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Affiliation(s)
- Donghai Wen
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
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Connective tissue growth factor modulates podocyte actin cytoskeleton and extracellular matrix synthesis and is induced in podocytes upon injury. Histochem Cell Biol 2011; 136:301-19. [DOI: 10.1007/s00418-011-0844-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2011] [Indexed: 12/19/2022]
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Bu X, Zhou Y, Zhang H, Qiu W, Chen L, Cao H, Fang L, Wen P, Tan R, Yang J. Systemic administration of naked plasmid encoding HGF attenuates puromycin aminonucleoside-induced damage of murine glomerular podocytes. Am J Physiol Renal Physiol 2011; 301:F784-92. [PMID: 21775482 DOI: 10.1152/ajprenal.00210.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Podocyte injury is considered to play important roles in the pathogenesis of human glomerular disease. There is accumulating evidence suggesting that hepatocyte growth factor (HGF) elicits preventive activity for glomerular cells in animal models of chronic renal diseases. In this study, we demonstrated that delivery of a naked plasmid vector encoding the human HGF gene into mice by a hydrodynamic-based in vivo gene transfection approach markedly reduced proteinuria and attenuated podocyte injury in a mouse model induced by puromycin aminonucleoside (PAN) injection. Systemic administration by rapid injection via the tail vein of a naked plasmid containing HGF cDNA driven under a cytomegalovirus promoter (pCMV-HGF) produced a remarkable level of human HGF protein in the circulation. Tissue distribution studies suggested that the kidney expressed a high level of the HGF transgene. Meanwhile, compared with tubules and interstitium, a higher level of exogenous HGF protein was detected in the glomeruli. Administration of pCMV-HGF dramatically abated the urine albumin excretion and podocyte injury in PAN nephropathy in mice. Exogenous expression of HGF produced evidently beneficial effects, leading to restoration of Wilms' tumor-1 (WT1) and α-actinin-4 expression and attenuation of ultrastructural damage of the podocytes. In vitro, HGF not only restored WT1 and α-actinin-4 expression but also inhibited albumin leakage of podocytes incubated with PAN in a Transwell culture chamber. These results suggest that HGF might provide a novel strategy for amelioration of podocyte injury.
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Affiliation(s)
- Xuan Bu
- Center of Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, China
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