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Meliambro K, He JC, Campbell KN. Podocyte-targeted therapies - progress and future directions. Nat Rev Nephrol 2024; 20:643-658. [PMID: 38724717 DOI: 10.1038/s41581-024-00843-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2024] [Indexed: 09/14/2024]
Abstract
Podocytes are the key target cells for injury across the spectrum of primary and secondary proteinuric kidney disorders, which account for up to 90% of cases of kidney failure worldwide. Seminal experimental and clinical studies have established a causative link between podocyte depletion and the magnitude of proteinuria in progressive glomerular disease. However, no substantial advances have been made in glomerular disease therapies, and the standard of care for podocytopathies relies on repurposed immunosuppressive drugs. The past two decades have seen a remarkable expansion in understanding of the mechanistic basis of podocyte injury, with prospects increasing for precision-based treatment approaches. Dozens of disease-causing genes with roles in the pathogenesis of clinical podocytopathies have been identified, as well as a number of putative glomerular permeability factors. These achievements, together with the identification of novel targets of podocyte injury, the development of potential approaches to harness the endogenous podocyte regenerative potential of progenitor cell populations, ongoing clinical trials of podocyte-specific pharmacological agents and the development of podocyte-directed drug delivery systems, contribute to an optimistic outlook for the future of glomerular disease therapy.
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Affiliation(s)
- Kristin Meliambro
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - John C He
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Kirk N Campbell
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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2
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Ding Y, Luan ZQ, Mao ZM, Qu Z, Yu F. Association between glomerular mTORC1 activation and crescents formation in lupus nephritis patients. Clin Immunol 2023; 249:109288. [PMID: 36907538 DOI: 10.1016/j.clim.2023.109288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 12/30/2022] [Accepted: 02/23/2023] [Indexed: 03/13/2023]
Abstract
OBJECTIVE This study aims to explore the association between glomerular mammalian target of rapamycin complex 1 (mTORC1) pathway activation and crescents' degree in lupus nephritis (LN) patients. METHODS A total of 159 biopsy-proven LN patients were enrolled in this retrospective study. The clinical and pathological data of them were collected at the time of renal biopsy. mTORC1 pathway activation was measured by immunohistochemistry, expressed by the mean optical density (MOD) of p-RPS6 (ser235/236), and multiplexed immunofluorescence. The association of mTORC1 pathway activation with clinico-pathological features especially renal crescentic lesions, and the composite outcomes in LN patients was further analyzed. RESULTS mTORC1 pathway activation could be detected in the crescentic lesions and was positively correlated with the percentage of crescents (r = 0.479, P < 0.001) in LN patients. Subgroup analysis showed mTORC1 pathway was more activated in patients with cellular or fibrocellular crescentic lesions (P < 0.001), but not fibrous crescentic lesions (P = 0.270). The optimal cutoff value of the MOD of p-RPS6 (ser235/236) was 0.0111299 for predicting the presence of cellular-fibrocellular crescents in >7.39% of the glomeruli by the receiver operating characteristic curve. Cox regression survival analysis showed that mTORC1 pathway activation was an independent risk factor for the worse outcome (defined by composite endpoints of death, end-stage renal disease and a decrease of >30% in eGFR from baseline). CONCLUSION Activation of mTORC1 pathway was closely associated with the cellular-fibrocellular crescentic lesions and could be a prognostic marker in LN patients.
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Affiliation(s)
- Ying Ding
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing 100034, PR China; Department of Nephrology, Peking University International Hospital, Beijing 102206, PR China; Institute of Nephrology, Peking University, Beijing 100034, PR China; Key laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, PR China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China
| | - Zhong-Qiu Luan
- Department of Nephrology, First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin 150040, PR China
| | - Zhao-Min Mao
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing 100034, PR China; Institute of Nephrology, Peking University, Beijing 100034, PR China; Key laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, PR China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China
| | - Zhen Qu
- Department of Nephrology, Peking University International Hospital, Beijing 102206, PR China.
| | - Feng Yu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing 100034, PR China; Department of Nephrology, Peking University International Hospital, Beijing 102206, PR China; Institute of Nephrology, Peking University, Beijing 100034, PR China; Key laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, PR China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing 100034, PR China
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3
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Shi H, Zhao Y, He T, Wen X, Qu G, Li S, Gan W, Zhang A. Rapamycin attenuated podocyte apoptosis via upregulation of nestin in Ang II-induced podocyte injury. Mol Biol Rep 2022; 49:2119-2128. [PMID: 35149934 PMCID: PMC8863685 DOI: 10.1007/s11033-021-07029-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 11/26/2021] [Indexed: 11/26/2022]
Abstract
Background Angiotensin II (Ang II) contributes to the progression of glomerulosclerosis, mainly by inducing podocyte injury. Convincing evidence indicates that the mTOR inhibitor rapamycin could play a fundamental role in protection against podocyte injury. Nestin, a major cytoskeletal protein, is stably expressed in podocytes and correlates with podocyte damage. The purpose of this study was to investigate the effect of rapamycin on podocyte injury induced by Ang II and to clarify the role and mechanism of nestin in the protective effect of rapamycin of podocyte injury. Methods and results We established an Ang II perfusion animal model, and the effects of rapamycin treatment on podocytes were investigated in vivo. In vitro, podocytes were stimulated with Ang II and rapamycin to observe podocyte injury, and nestin-siRNA was transfected to investigate the underlying mechanisms. We observed that Ang II induced podocyte injury both in vivo and in vitro, whereas rapamycin treatment relieved Ang II-induced podocyte injury. We further found that nestin co-localized with p-mTOR in glomeruli, and the protective effect of rapamycin was reduced by nestin-siRNA in podocytes. Moreover, co-IP indicated the interaction between nestin and p-mTOR, and nestin could affect podocyte injury via the mTOR/P70S6K signaling pathway. Conclusion We demonstrated that rapamycin attenuated podocyte apoptosis via upregulation of nestin expression through the mTOR/P70S6K signaling pathway in an Ang II-induced podocyte injury.
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Affiliation(s)
- Huimin Shi
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China
| | - Yajie Zhao
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China
| | - Tiantian He
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China
| | - Xianli Wen
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China
| | - Gaoting Qu
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China
| | - Shanwen Li
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China
| | - Weihua Gan
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China.
| | - Aiqing Zhang
- Department of Pediatric Nephrology, The Second Affiliated Hospital of Nanjing Medical University, 262 Zhongshan North Road, Nanjing, 210003, Jiangsu Province, China.
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4
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Wang X, Chen J, Xu J, Xie J, Harris DCH, Zheng G. The Role of Macrophages in Kidney Fibrosis. Front Physiol 2021; 12:705838. [PMID: 34421643 PMCID: PMC8378534 DOI: 10.3389/fphys.2021.705838] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/07/2021] [Indexed: 12/27/2022] Open
Abstract
The phenotypic heterogeneity and functional diversity of macrophages confer on them complexed roles in the development and progression of kidney diseases. After kidney injury, bone marrow-derived monocytes are rapidly recruited to the glomerulus and tubulointerstitium. They are activated and differentiated on site into pro-inflammatory M1 macrophages, which initiate Th1-type adaptive immune responses and damage normal tissues. In contrast, anti-inflammatory M2 macrophages induce Th2-type immune responses, secrete large amounts of TGF-β and anti-inflammatory cytokines, transform into αSMA+ myofibroblasts in injured kidney, inhibit immune responses, and promote wound healing and tissue fibrosis. Previous studies on the role of macrophages in kidney fibrosis were mainly focused on inflammation-associated injury and injury repair. Apart from macrophage-secreted profibrotic cytokines, such as TGF-β, evidence for a direct contribution of macrophages to kidney fibrosis is lacking. However, under inflammatory conditions, Wnt ligands are derived mainly from macrophages and Wnt signaling is central in the network of multiple profibrotic pathways. Largely underinvestigated are the direct contribution of macrophages to profibrotic signaling pathways, macrophage phenotypic heterogeneity and functional diversity in relation to kidney fibrosis, and on their cross-talk with other cells in profibrotic signaling networks that cause fibrosis. Here we aim to provide an overview on the roles of macrophage phenotypic and functional diversity in their contribution to pro-fibrotic signaling pathways, and on the therapeutic potential of targeting macrophages for the treatment of kidney fibrosis.
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Affiliation(s)
- Xiaoling Wang
- Shanxi Key Laboratory of Birth Defect and Cell Regeneration, Shanxi Medical University, Taiyuan, China
- Clinical Laboratory, Shanxi Academy of Traditional Chinese Medicine, Taiyuan, China
| | - Jianwei Chen
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Jun Xu
- Department of General Surgery, First Hospital of Shanxi Medical University, Taiyuan, China
| | - Jun Xie
- Shanxi Key Laboratory of Birth Defect and Cell Regeneration, Shanxi Medical University, Taiyuan, China
| | - David C. H. Harris
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - Guoping Zheng
- Centre for Transplant and Renal Research, Westmead Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
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5
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Denhez B, Rousseau M, Spino C, Dancosst DA, Dumas MÈ, Guay A, Lizotte F, Geraldes P. Saturated fatty acids induce insulin resistance in podocytes through inhibition of IRS1 via activation of both IKKβ and mTORC1. Sci Rep 2020; 10:21628. [PMID: 33303821 PMCID: PMC7728775 DOI: 10.1038/s41598-020-78376-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 11/17/2020] [Indexed: 12/31/2022] Open
Abstract
Diabetic nephropathy (DN), a microvascular complication of diabetes, is the leading cause of end-stage renal disease worldwide. Multiple studies have shown that podocyte dysfunction is a central event in the progression of the disease. Beside chronic hyperglycemia, dyslipidemia can induce insulin resistance and dysfunction in podocytes. However, the exact mechanisms of free fatty acid (FFA)-induced podocyte insulin unresponsiveness are poorly understood. We used a type 2 diabetic mouse model (db/db) and mouse podocytes exposed to palmitic acid for 24 h followed by an insulin stimulation. Renal function and pathology were evaluated at 25 weeks of age to confirm the DN development. Our results demonstrate that saturated FFA activated the serine/threonine kinases IκB kinase (IKK)β/IκBα and mTORC1/S6K1, but not protein kinase C and c-jun N-terminal kinase, in podocytes and glomeruli of db/db mice. Activation of both kinases promoted serine 307 phosphorylation of IRS1, a residue known to provoke IRS1 inhibition. Using IKK, mTORC1 and ceramide production inhibitors, we were able to blunt IRS1 serine 307 phosphorylation and restore insulin stimulation of Akt. In conclusion, our results indicate that FFA and diabetes contribute to insulin resistance through the activation of IKKβ and S6K1 leading to podocyte dysfunction and DN.
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Affiliation(s)
- Benoit Denhez
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - Marina Rousseau
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - Crysta Spino
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - David-Alexandre Dancosst
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - Marie-Ève Dumas
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - Andréanne Guay
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - Farah Lizotte
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada
| | - Pedro Geraldes
- From the Research Center of the Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada. .,Division of Endocrinology, Department of Medicine, Université de Sherbrooke, 3001 12e Ave Nord, Sherbrooke, QC, J1H 5N4, Canada.
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6
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Gui Y, Dai C. mTOR Signaling in Kidney Diseases. KIDNEY360 2020; 1:1319-1327. [PMID: 35372878 PMCID: PMC8815517 DOI: 10.34067/kid.0003782020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/02/2020] [Indexed: 04/27/2023]
Abstract
The mammalian target of rapamycin (mTOR), a serine/threonine protein kinase, is crucial in regulating cell growth, metabolism, proliferation, and survival. Under physiologic conditions, mTOR signaling maintains podocyte and tubular cell homeostasis. In AKI, activation of mTOR signaling in tubular cells and interstitial fibroblasts promotes renal regeneration and repair. However, constitutive activation of mTOR signaling in kidneys results in the initiation and progression of glomerular hypertrophy, interstitial fibrosis, polycystic kidney disease, and renal cell carcinoma. Here, we summarize the recent studies about mTOR signaling in renal physiology and injury, and discuss the possibility of its use as a therapeutic target for kidney diseases.
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Affiliation(s)
- Yuan Gui
- Department of Nephrology, University of Connecticut Health Center, Farmington, Connecticut
| | - Chunsun Dai
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
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7
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Inhibition of mTOR delayed but could not prevent experimental collapsing focal segmental glomerulosclerosis. Sci Rep 2020; 10:8580. [PMID: 32444668 PMCID: PMC7244565 DOI: 10.1038/s41598-020-65352-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 04/30/2020] [Indexed: 02/06/2023] Open
Abstract
Anti-Thy1.1 transgenic mice develop glomerular lesions that mimic collapsing focal segmental glomerulosclerosis (FSGS) in humans with collapse of the glomerular tuft and marked hyperplasia of the parietal epithelial cells (PECs). Immunostaining of phosphor-S6 ribosomal protein (pS6RP) revealed high mTOR activity in PECs of the FSGS lesions of these mice. In this study we questioned whether the mTOR inhibitor rapamycin (sirolimus) could attenuate the development and progression of glomerulosclerotic lesions in the anti-Thy1.1 transgenic mice. We observed reduced mTOR signalling and proliferation in human parietal epithelial cells after rapamycin treatment. Experiments with anti-Thy1.1. mice showed that early treatment with sirolimus reduced the development of glomerular lesions and glomerular cell proliferation at day 4. Levels of albuminuria, podocyte injury and podocyte number were similar in the sirolimus and vehicle treated groups. The initial beneficial effects of sirolimus treatment were not observed at day 7. Late sirolimus treatment did not reduce albuminuria or the progression of glomerulosclerosis. Taken together, rapamycin attenuated PEC proliferation and the formation of early FSGS lesions in experimental FSGS and reduced human PEC proliferation in vitro. However, the initial inhibition of PEC proliferation did not translate into a decline of albuminuria nor in a sustained reduction in sclerotic lesions.
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8
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Cao H, Luo J, Zhang Y, Mao X, Wen P, Ding H, Xu J, Sun Q, He W, Dai C, Zen K, Zhou Y, Yang J, Jiang L. Tuberous sclerosis 1 (Tsc1) mediated mTORC1 activation promotes glycolysis in tubular epithelial cells in kidney fibrosis. Kidney Int 2020; 98:686-698. [PMID: 32739207 DOI: 10.1016/j.kint.2020.03.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 03/12/2020] [Accepted: 03/19/2020] [Indexed: 10/24/2022]
Abstract
Energy reprogramming to glycolysis is closely associated with the development of chronic kidney disease. As an important negative regulatory factor of the mammalian target of rapamycin complex 1 (mTORC1) signal, tuberous sclerosis complex 1 (Tsc1) is also a key regulatory point of glycolysis. Here, we investigated whether Tsc1 could mediate the progression of kidney interstitial fibrosis by regulating glycolysis in proximal tubular epithelial cells. We induced mTORC1 signal activation in tubular epithelial cells in kidneys with fibrosis via unilateral ureteral occlusion. This resulted in increased tubular epithelial cell proliferation and glycolytic enzyme upregulation. Prior incubation with rapamycin inhibited mTORC1 activation and abolished the enhanced glycolysis and tubular epithelial cell proliferation. Furthermore, knockdown of Tsc1 expression promoted glycolysis in the rat kidney epithelial cell line NRK-52E. Specific deletion of Tsc1 in the proximal tubules of mice resulted in enlarged kidneys characterized by a high proportion of proliferative tubular epithelial cells, dilated tubules with cyst formation, and a large area of interstitial fibrosis in conjunction with elevated glycolysis. Treatment of the mice with the glycolysis inhibitor 2-deoxyglucose notably ameliorated tubular epithelial cell proliferation, cystogenesis, and kidney fibrosis. Thus, our findings suggest that Tsc1-associated mTORC1 signaling mediates the progression of kidney interstitial fibrosis by regulating glycolysis in proximal tubular epithelial cells.
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Affiliation(s)
- Hongdi Cao
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jing Luo
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yu Zhang
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xiaoming Mao
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ping Wen
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Hao Ding
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jing Xu
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Qi Sun
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Weichun He
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Chunsun Dai
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ke Zen
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University Advanced Institute of Life Sciences, Nanjing, Jiangsu, China
| | - Yang Zhou
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
| | - Junwei Yang
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
| | - Lei Jiang
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
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Iwata W, Unoki-Kubota H, Kato H, Shimizu A, Matsumoto M, Imasawa T, Igarashi A, Matsumoto K, Noda T, Terauchi Y, Nangaku M, Kasuga M, Kaburagi Y. Podocyte-specific deletion of tubular sclerosis complex 2 promotes focal segmental glomerulosclerosis and progressive renal failure. PLoS One 2020; 15:e0229397. [PMID: 32191726 PMCID: PMC7082048 DOI: 10.1371/journal.pone.0229397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 02/05/2020] [Indexed: 02/06/2023] Open
Abstract
Obesity can initiate and accelerate the progression of kidney diseases. However, it remains unclear how obesity affects renal dysfunction. Here, we show that a newly generated podocyte-specific tubular sclerosis complex 2 (Tsc2) knockout mouse model (Tsc2Δpodocyte) develops proteinuria and dies due to end-stage renal dysfunction by 10 weeks of age. Tsc2Δpodocyte mice exhibit an increased glomerular size and focal segmental glomerulosclerosis, including podocyte foot process effacement, mesangial sclerosis and proteinaceous casts. Podocytes isolated from Tsc2Δpodocyte mice show nuclear factor, erythroid derived 2, like 2-mediated increased oxidative stress response on microarray analysis and their autophagic activity is lowered through the mammalian target of rapamycin (mTOR)-unc-51-like kinase 1 pathway. Rapamycin attenuated podocyte dysfunction and extends survival in Tsc2Δpodocyte mice. Additionally, mTOR complex 1 (mTORC1) activity is increased in podocytes of renal biopsy specimens obtained from obese patients with chronic kidney disease. Our work shows that mTORC1 hyperactivation in podocytes leads to severe renal dysfunction and that inhibition of mTORC1 activity in podocytes could be a key therapeutic target for obesity-related kidney diseases.
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Affiliation(s)
- Wakiko Iwata
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
- Department of Endocrinology and Metabolism, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Hiroyuki Unoki-Kubota
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Hideki Kato
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Akira Shimizu
- Department of Analytic Human Pathology, Nippon Medical School, Tokyo, Japan
| | - Michihiro Matsumoto
- Department of Molecular Metabolic Regulation, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Toshiyuki Imasawa
- Kidney Center, National Hospital Organization Chiba-Higashi National Hospital, Chiba, Japan
| | - Arisa Igarashi
- Department of Allergy and Clinical Immunology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Kenji Matsumoto
- Department of Allergy and Clinical Immunology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Tetsuo Noda
- Cancer Institute of Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masato Kasuga
- National Center for Global Health and Medicine, Tokyo, Japan
| | - Yasushi Kaburagi
- Department of Diabetic Complications, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
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10
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Soypacaci Z, Cakmak O, Cakalagoglu F, Gercik O, Ertekin I, Uzum A, Ersoy R, Akar S. The role of mammalian target of rapamycin pathway in the pathogenesis of pauci-immune glomerulonephritis. Ren Fail 2019; 41:907-913. [PMID: 31658846 PMCID: PMC7011872 DOI: 10.1080/0886022x.2019.1667829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Background: The characteristic lesion of pauci-immune glomerulonephritis is focal necrotizing and crescentic glomerulonephritis. The underlying mechanisms in the formation or progression of crescent formation need further investigations. Therefore, we aimed to evaluate the role of mammalian target of rapamycin (mTOR), which might be a potential therapeutic target, in kidney biopsies of patients with pauci-immune glomerulonephritis. Methods: The patients diagnosed as pauci-immune glomerulonephritis at an outpatient nephrology clinic were retrospectively reviewed and those patients who had a kidney biopsy before receiving an immunosuppressive treatment were included in the study. Kidney biopsy specimens were immunohistochemically stained with mTOR, antibodies of phosphatase and tensin homolog (PTEN) and transforming growth factor-β (TGF-β) and scored by an experienced renal pathologist. Results: In total, 54 patients with pauci-immune glomerulonephritis (28 [52%] female) were included. According to the histopathologic examination, 22% of our cases were classified as focal, 33% crescentic, 22% mixed, and 22% as sclerotic. The mTOR was expressed in substantial percentages of glomeruli of patients with pauci-immune glomerulonephritis. However, we observed PTEN expression in all samples and mTOR in all tubulointerstitial areas. mTOR expression was found to be related with the presence of crescentic and sclerotic changes observed in glomeruli and the degree of fibrosis in interstitial areas. Serum creatinine level or response to treatment was not found to be associated with mTOR pathway expression. Conclusion: Our results suggest that mTOR pathway may play role in the pathogenesis of pauci-immune glomerulonephritis, besides targeting this signaling may be an alternative option for those patients.
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Affiliation(s)
- Zeki Soypacaci
- Department of Nephrology, Izmir Katip Celebi University , Izmir , Turkey
| | - Ozlem Cakmak
- Department of Internal Medicine, Izmir Katip Celebi University , Izmir , Turkey
| | - Fulya Cakalagoglu
- Department of Pathology, Izmir Katip Celebi University , Izmir , Turkey
| | - Onay Gercik
- Department of Rheumatology, Izmir Katip Celebi University , Izmir , Turkey
| | - Ibrahim Ertekin
- Department of Nephrology, Izmir Katip Celebi University , Izmir , Turkey
| | - Atilla Uzum
- Department of Nephrology, Izmir Katip Celebi University , Izmir , Turkey
| | - Rifki Ersoy
- Department of Nephrology, Izmir Katip Celebi University , Izmir , Turkey
| | - Servet Akar
- Department of Rheumatology, Izmir Katip Celebi University , Izmir , Turkey
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11
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Association of crumbs homolog-2 with mTORC1 in developing podocyte. PLoS One 2018; 13:e0202400. [PMID: 30125302 PMCID: PMC6101391 DOI: 10.1371/journal.pone.0202400] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 08/02/2018] [Indexed: 02/06/2023] Open
Abstract
The evidence that gene mutations in the polarity determinant Crumbs homologs-2 (CRB2) cause congenital nephrotic syndrome suggests the functional importance of this gene product in podocyte development. Because another isoform, CRB3, was reported to repress the mechanistic/mammalian target of the rapamycin complex 1 (mTORC1) pathway, we examined the role of CRB2 function in developing podocytes in relation to mTORC1. In HEK-293 and MDCK cells constitutively expressing CRB2, we found that the protein localized to the apicolateral side of the cell plasma membrane and that this plasma membrane assembly required N-glycosylation. Confocal microscopy of the neonate mouse kidney revealed that both the tyrosine-phosphorylated form and non-phosphorylated form of CRB2 commence at the S-shaped body stage at the apicolateral side of podocyte precursor cells and move to foot processes in a capillary tuft pattern. The pattern of phosphorylated mTOR in developing podocytes was similar to that of CRB2 tyrosine phosphorylation. Additionally, the lack of a tyrosine phosphorylation site on CRB2 led to the reduced sensitivity of mTORC1 activation in response to energy starvation. CRB2 may play an important role in the mechanistic pathway of developing podocytes through tyrosine phosphorylation by associating with mTORC1 activation.
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Zschiedrich S, Bork T, Liang W, Wanner N, Eulenbruch K, Munder S, Hartleben B, Kretz O, Gerber S, Simons M, Viau A, Burtin M, Wei C, Reiser J, Herbach N, Rastaldi MP, Cohen CD, Tharaux PL, Terzi F, Walz G, Gödel M, Huber TB. Targeting mTOR Signaling Can Prevent the Progression of FSGS. J Am Soc Nephrol 2017; 28:2144-2157. [PMID: 28270414 DOI: 10.1681/asn.2016050519] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 01/16/2017] [Indexed: 01/04/2023] Open
Abstract
Mammalian target of rapamycin (mTOR) signaling is involved in a variety of kidney diseases. Clinical trials administering mTOR inhibitors to patients with FSGS, a prototypic podocyte disease, led to conflicting results, ranging from remission to deterioration of kidney function. Here, we combined complex genetic titration of mTOR complex 1 (mTORC1) levels in murine glomerular disease models, pharmacologic studies, and human studies to precisely delineate the role of mTOR in FSGS. mTORC1 target genes were significantly induced in microdissected glomeruli from both patients with FSGS and a murine FSGS model. Furthermore, a mouse model with constitutive mTORC1 activation closely recapitulated human FSGS. Notably, the complete knockout of mTORC1 by induced deletion of both Raptor alleles accelerated the progression of murine FSGS models. However, lowering mTORC1 signaling by deleting just one Raptor allele ameliorated the progression of glomerulosclerosis. Similarly, low-dose treatment with the mTORC1 inhibitor rapamycin efficiently diminished disease progression. Mechanistically, complete pharmacologic inhibition of mTOR in immortalized podocytes shifted the cellular energy metabolism toward reduced rates of oxidative phosphorylation and anaerobic glycolysis, which correlated with increased production of reactive oxygen species. Together, these data suggest that podocyte injury and loss is commonly followed by adaptive mTOR activation. Prolonged mTOR activation, however, results in a metabolic podocyte reprogramming leading to increased cellular stress and dedifferentiation, thus offering a treatment rationale for incomplete mTOR inhibition.
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Affiliation(s)
- Stefan Zschiedrich
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Tillmann Bork
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Wei Liang
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany.,Division of Nephrology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Nicola Wanner
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Kristina Eulenbruch
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Stefan Munder
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Björn Hartleben
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Oliver Kretz
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, and
| | - Simon Gerber
- Imagine Institute, Institut national de la santé et de la recherche médicale (INSERM) U1163, Paris Descartes University-Sorbonne Paris Cité, Paris, France
| | - Matias Simons
- Imagine Institute, Institut national de la santé et de la recherche médicale (INSERM) U1163, Paris Descartes University-Sorbonne Paris Cité, Paris, France
| | - Amandine Viau
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Martine Burtin
- Institut national de la santé et de la recherche médicale (INSERM) U1151, Université Paris Descartes, Institut Necker Enfants Malades, Hopital Necker, Paris, France
| | - Changli Wei
- Department of Medicine, Rush University Medical Center, Chicago, IL
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL
| | - Nadja Herbach
- Institute of Veterinary Pathology, Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-University, Munich, Germany
| | - Maria-Pia Rastaldi
- Renal Research Laboratory, Fondazione Istituto di ricovero e cura a carattere scientifico (IRCCS) Ospedale Maggiore Policlinico and Fondazione D'Amico, Milan, Italy
| | - Clemens D Cohen
- Division of Nephrology, Hypertension and Clinical Immunology, Städtisches Klinikum München, Munich, Germany
| | - Pierre-Louis Tharaux
- Paris Cardiovascular Research Centre (PARCC), Institut National de la Santé et de la Recherche Médicale, Paris, France; and
| | - Fabiola Terzi
- Institut national de la santé et de la recherche médicale (INSERM) U1151, Université Paris Descartes, Institut Necker Enfants Malades, Hopital Necker, Paris, France
| | - Gerd Walz
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Markus Gödel
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany
| | - Tobias B Huber
- Department of Medicine IV, Faculty of Medicine, University of Freiburg, Germany; .,BIOSS Centre for Biological Signalling Studies, and.,Center for Systems Biology (ZBSA), Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Department of Medicine III, Faculty of Medicine University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Roles of mTOR complexes in the kidney: implications for renal disease and transplantation. Nat Rev Nephrol 2016; 12:587-609. [PMID: 27477490 DOI: 10.1038/nrneph.2016.108] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The mTOR pathway has a central role in the regulation of cell metabolism, growth and proliferation. Studies involving selective gene targeting of mTOR complexes (mTORC1 and mTORC2) in renal cell populations and/or pharmacologic mTOR inhibition have revealed important roles of mTOR in podocyte homeostasis and tubular transport. Important advances have also been made in understanding the role of mTOR in renal injury, polycystic kidney disease and glomerular diseases, including diabetic nephropathy. Novel insights into the roles of mTORC1 and mTORC2 in the regulation of immune cell homeostasis and function are helping to improve understanding of the complex effects of mTOR targeting on immune responses, including those that impact both de novo renal disease and renal allograft outcomes. Extensive experience in clinical renal transplantation has resulted in successful conversion of patients from calcineurin inhibitors to mTOR inhibitors at various times post-transplantation, with excellent long-term graft function. Widespread use of this practice has, however, been limited owing to mTOR-inhibitor- related toxicities. Unique attributes of mTOR inhibitors include reduced rates of squamous cell carcinoma and cytomegalovirus infection compared to other regimens. As understanding of the mechanisms by which mTORC1 and mTORC2 drive the pathogenesis of renal disease progresses, clinical studies of mTOR pathway targeting will enable testing of evolving hypotheses.
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McNicholas BA, Eng DG, Lichtnekert J, Rabinowitz PS, Pippin JW, Shankland SJ. Reducing mTOR augments parietal epithelial cell density in a model of acute podocyte depletion and in aged kidneys. Am J Physiol Renal Physiol 2016; 311:F626-39. [PMID: 27440779 PMCID: PMC5142165 DOI: 10.1152/ajprenal.00196.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/12/2016] [Indexed: 02/06/2023] Open
Abstract
Parietal epithelial cell (PEC) response to glomerular injury may underlie a common pathway driving fibrogenesis following podocyte loss that typifies several glomerular disorders. Although the mammalian target of rapamycin (mTOR) pathway is important in cell homeostasis, little is known of the biological role or impact of reducing mTOR activity on PEC response following podocyte depletion, nor in the aging kidney. The purpose of these studies was to determine the impact on PECs of reducing mTOR activity following abrupt experimental depletion in podocyte number, as well as in a model of chronic podocyte loss and sclerosis associated with aging. Podocyte depletion was induced by an anti-podocyte antibody and rapamycin started at day 5 until death at day 14 Reducing mTOR did not lead to a greater reduction in podocyte density, despite greater glomerulosclerosis. However, mTOR inhibition lead to an increase in PEC density and PEC-derived crescent formation. Additionally, markers of epithelial-to-mesenchymal transition (platelet-derived growth factor receptor-β, α-smooth muscle actin, Notch-3) and PEC activation (CD44, collagen IV) were further increased by mTOR reduction. Aged mice treated with rapamycin for 1, 2, and 10 wk before death at 26.5 mo (≈75-yr-old human age) had increased the number of glomeruli with a crescentic appearance. mTOR inhibition at either a high or low level lead to changes in PEC phenotype, indicating PEC morphology is sensitive to changes mediated by global mTOR inhibition.
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Affiliation(s)
| | - Diana G Eng
- Division of Nephrology, University of Washington, Seattle, Washington; and
| | - Julia Lichtnekert
- Division of Nephrology, University of Washington, Seattle, Washington; and
| | | | - Jeffrey W Pippin
- Division of Nephrology, University of Washington, Seattle, Washington; and
| | - Stuart J Shankland
- Division of Nephrology, University of Washington, Seattle, Washington; and
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