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Liu X, Fang H, Liang D, Lei Q, Wang J, Xu F, Liang S, Liang D, Yang F, Li H, Chen J, Ni Y, Xie G, Zeng C. Advancing the application of the analytical renal pathology system in allograft IgA nephropathy patients. Ren Fail 2024; 46:2322043. [PMID: 38425049 PMCID: PMC10911252 DOI: 10.1080/0886022x.2024.2322043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 02/16/2024] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND The analytical renal pathology system (ARPS) based on convolutional neural networks has been used successfully in native IgA nephropathy (IgAN) patients. Considering the similarity of pathologic features, we aim to evaluate the performance of the ARPS in allograft IgAN patients and broaden its implementation. METHODS Biopsy-proven allograft IgAN patients from two different centers were enrolled for internal and external validation. We implemented the ARPS to identify glomerular lesions and intrinsic glomerular cells, and then evaluated its performance. Consistency between the ARPS and pathologists was assessed using intraclass correlation coefficients. The association of digital pathological features with clinical and pathological data was measured. Kaplan-Meier survival curve and cox proportional hazards model were applied to investigate prognosis prediction. RESULTS A total of 56 biopsy-proven allograft IgAN patients from the internal center and 17 biopsy-proven allograft IgAN patients from the external center were enrolled in this study. The ARPS was successfully applied to identify the glomerular lesions (F1-score, 0.696-0.959) and quantify intrinsic glomerular cells (F1-score, 0.888-0.968) in allograft IgAN patients rapidly and precisely. Furthermore, the mesangial hypercellularity score was positively correlated with all mesangial metrics provided by ARPS [Spearman's correlation coefficient (r), 0.439-0.472, and all p values < 0.001]. Besides, a higher allograft survival was noticed among patients in the high-level groups of the maximum and ratio of endothelial cells, as well as the maximum and density of podocytes. CONCLUSION We propose that the ARPS could be implemented in future clinical practice with outstanding capability.
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Affiliation(s)
- Xumeng Liu
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Huiwen Fang
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Dongmei Liang
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Qunjuan Lei
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | | | - Feng Xu
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Shaoshan Liang
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Dandan Liang
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Fan Yang
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Heng Li
- Kidney Disease Center, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang, China
| | - Jianghua Chen
- Kidney Disease Center, First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang, China
| | - Yuan Ni
- Ping An Healthcare Technology, Shanghai, China
| | - Guotong Xie
- Ping An Healthcare Technology, Shanghai, China
| | - Caihong Zeng
- National Clinical Research Center for Kidney Diseases, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
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dos Santos PF, de Souza DB, Torres EJL, Costa WS, Sampaio FJB, Gregorio BM. Metabolic and ultrastructural renal changes in adult Wistar rats fed by a cafeteria diet. Acta Cir Bras 2024; 39:e392224. [PMID: 38629653 PMCID: PMC11020636 DOI: 10.1590/acb392224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/14/2024] [Indexed: 04/19/2024] Open
Abstract
PURPOSE To evaluate, by quantitative and qualitative methods, the glomerular ultrastructure in Wistar rats fed a cafeteria diet. METHODS Male Wistar rats were divided into two groups at 21 days of age: control (C, n = 10) and cafeteria diet (CAF, n = 8). The animals were followed up until 5 months of age, followed by euthanasia. The blood, kidneys, and fat deposits--epididymal, retroperitoneal, and subcutaneous--were extracted and analyzed. Data were analyzed by Student's t test, and p < 0.05 was considered statistically significant. RESULTS The cafeteria diet promoted glucose intolerance, hyperglycemia (p < 0.0001), and deposition of retroperitoneal fat (p < 0.005). Scanning electron microscopy revealed that the length of the foot process was similar in both groups. The quantitative analyses by transmission electron microscopy revealed that the cafeteria diet reduced the thickness of the glomerular basement membrane (p < 0.05). CONCLUSIONS The intake of lipids and simple carbohydrates were found to be associated with alteration in the glomerular ultrastructure. However, more studies are needed to evaluate not only the effects of high-protein and high-fat diets on components of the glomerular filtration barrier, but also renal physiology.
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Affiliation(s)
| | - Diogo Benchimol de Souza
- Universidade do Estado do Rio de Janeiro – Biomedical Center – Department of Anatomy – Rio de Janeiro (RJ) – Brazil
| | - Eduardo José Lopes Torres
- Universidade do Estado do Rio de Janeiro – Biomedical Center – Department of Microbiology, Immunology and Parasitology – Rio de Janeiro (RJ) – Brazil
| | - Waldemar Silva Costa
- Universidade do Estado do Rio de Janeiro – Biomedical Center – Department of Anatomy – Rio de Janeiro (RJ) – Brazil
| | | | - Bianca Martins Gregorio
- Universidade do Estado do Rio de Janeiro – Biomedical Center – Department of Anatomy – Rio de Janeiro (RJ) – Brazil
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Dong J, Jiang Z, Ma G. Hsp90 inhibition aggravates adriamycin-induced podocyte injury through intrinsic apoptosis pathway. Exp Cell Res 2020; 390:111928. [PMID: 32156599 DOI: 10.1016/j.yexcr.2020.111928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/09/2020] [Accepted: 02/25/2020] [Indexed: 12/14/2022]
Abstract
Podocyte injury leads to impaired filtration barrier function of the kidney that underlies the pathophysiology of idiopathic nephrotic syndrome (INS), the most common NS occurring in children. The heat shock protein 90 (Hsp90) is involved in the regulation of apoptosis in a variety of cell types, however, little is known about its role in podocytes and whether it associated with NS. Here, we show that Hsp90 is upregulated in glomeruli podocytes from mice with adriamycin (ADR)-induced nephropathy, and that it is also upregulated in an immortalized podocyte cell line treated with ADR in vitro, together suggesting an association of Hsp90 upregulation in podocytes with NS pathogenesis. Functionally, Hsp90 inhibition with PU-H71 aggravates ADR-induced podocyte apoptosis and worsens the impairment of filtration barrier function. Mechanistically, Hsp90 inhibition with PU-H71 enhances the activation of intrinsic apoptotic pathway, and moreover, blockade of podocyte apoptosis with zVAD-fmk (aVAD), a pan-caspase inhibitor, abrogates effects of Hsp90 inhibition on filtration barrier function of ADR-treated podocytes, thus demonstrating that Hsp90 inhibition aggravates ADR-induced podocyte injury through intrinsic apoptosis pathway. In sum, this study reveals a detrimental role of Hsp90 inhibition in podocyte injury, which may offer it as a potential therapeutic target in NS therapy.
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Affiliation(s)
- Junyu Dong
- Department of Paediatrics, The First Affiliated Hospital of Henan University of Science & Technology, Luoyang, Henan, 471000, China
| | - Zhihong Jiang
- Department of Paediatrics, The First Affiliated Hospital of Henan University of Science & Technology, Luoyang, Henan, 471000, China.
| | - Guorui Ma
- Department of Paediatrics, The First Affiliated Hospital of Henan University of Science & Technology, Luoyang, Henan, 471000, China
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Wang B, Ding W, Zhang M, Li H, Guo H, Lin L, Chen J, Gu Y. Role of FOXO1 in aldosterone-induced autophagy: a compensatory protective mechanism related to podocyte injury. Oncotarget 2018; 7:45331-45351. [PMID: 27244896 PMCID: PMC5216726 DOI: 10.18632/oncotarget.9644] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 04/16/2016] [Indexed: 02/07/2023] Open
Abstract
This study was undertaken to elucidate whether and how autophagy was regulated in aldosterone (Aldo)-induced podocyte injury and to examine its role in this model both in vitro and in vivo. In cultured podocytes, Aldo increased autophagy flux as indicated by the enhanced expression of LC3-II/LC3-I and the reduction of p62. Autophagy induction with rapamycin (RP) provided a cytoprotective effect, and inhibition of autophagy with Atg7-specific siRNA, chloroquine (CQ) or 3-methyladenine (3-MA) worsened Aldo-induced podocyte injury by attenuating endoplasmic reticulum (ER) stress. Aldo inhibited Akt phosphorylation but increased the mammalian target of rapamycin (mTOR) signaling pathway; however, Aldo up-regulated the expression of FOXO1 and its downstream effector Rab7. Either knockdown of FOXO1 or Rab7 inhibited Aldo-induced autophagy. Additionally, an elevated level of P300-regulated acetylation of FOXO1 and the interaction of acetylated FOXO1 and Atg7 were also confirmed to be involved in regulating autophagy in Aldo-induced podocytes. Similar results were further confirmed in vivo. We propose that autophagy enhancement through enhancing of the FOXO1/Rab7 axis and post-translational modification of FOXO1 may represent a potential therapeutic strategy against podocyte injury by promoting autophagy.
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Affiliation(s)
- Bin Wang
- Division of Nephrology, Huashan Hospital and Institute of Nephrology, Fudan University, Shanghai, China
| | - Wei Ding
- Division of Nephrology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Minmin Zhang
- Division of Nephrology, Huashan Hospital and Institute of Nephrology, Fudan University, Shanghai, China
| | - Hongmei Li
- Division of Nephrology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
| | - Honglei Guo
- Division of Nephrology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
| | - Lilu Lin
- Division of Nephrology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China
| | - Jing Chen
- Division of Nephrology, Huashan Hospital and Institute of Nephrology, Fudan University, Shanghai, China
| | - Yong Gu
- Division of Nephrology, Huashan Hospital and Institute of Nephrology, Fudan University, Shanghai, China
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Chen X, Xu Y, Cheng Z, Su H, Liu X, Xu D, Kapron C, Liu J. Low-dose cadmium activates the JNK signaling pathway in human renal podocytes. Int J Mol Med 2018; 41:2359-2365. [PMID: 29393374 DOI: 10.3892/ijmm.2018.3445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 01/24/2018] [Indexed: 11/05/2022] Open
Abstract
Cadmium (Cd) is an environmental toxin. Our previous study demonstrated that low‑dose Cd damages the integrity of the glomerular filtration barrier (GFB); however, the underlying mechanisms are poorly understood. Podocytes are a major component of the GFB, which regulate the passage of proteins. The present study aimed to investigate the effects of low‑dose Cd on human renal podocytes (HRPs). HRPs were treated with Cd and activation of the c-Jun N-terminal kinase (JNK) pathway was examined by western blot analysis. Proliferation, viability and apoptosis of HRPs were evaluated by MTT assay, trypan blue exclusion assay and flow cytometry, respectively. The properties of HRPs were validated by immunofluorescence staining and Phalloidin‑labeling. The results indicated that 4 µM Cd may activate the JNK pathway, and increase the protein expression levels of c‑Jun and c‑Fos. However, proliferation, viability, apoptosis and alignment of the F‑actin cytoskeleton in HRPs were not significantly affected by Cd treatment, with or without SP600125 pretreatment. In addition, the expression levels of CD2‑associated protein and synaptopodin, which are differentiation markers of HRPs, remained unchanged following Cd treatment. These results indicated that low‑dose Cd activates the JNK pathway but does not significantly affect HRP function.
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Affiliation(s)
- Xiaocui Chen
- Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
| | - Yinghua Xu
- School of Graduate Studies, Taishan Medical College, Tai'an, Shandong 271000, P.R. China
| | - Zuowang Cheng
- School of Graduate Studies, Taishan Medical College, Tai'an, Shandong 271000, P.R. China
| | - Hong Su
- Department of Nephrology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
| | - Xiu Liu
- Department of Cardiography, Binzhou Medical University Affiliated Hospital, Binzhou, Shandong 256600, P.R. China
| | - Dongmei Xu
- Department of Nephrology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
| | - Carolyn Kapron
- Department of Biology, Trent University, Peterborough, ON K9J 7B8, Canada
| | - Ju Liu
- Medical Research Center, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, P.R. China
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Yang X, Wu D, Du H, Nie F, Pang X, Xu Y. MicroRNA-135a is involved in podocyte injury in a transient receptor potential channel 1-dependent manner. Int J Mol Med 2017; 40:1511-1519. [PMID: 28949388 PMCID: PMC5627871 DOI: 10.3892/ijmm.2017.3152] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 09/18/2017] [Indexed: 12/03/2022] Open
Abstract
Transient receptor potential (TRP) cation channels are essential for normal cellular physiology, and their abnormal expression may lead to a number of disorders, including podocytopathy. Therefore, it is crucial to understand the mechanisms underlying the regulation of TRP channels. In the present study, microRNA (miR)-135a was found to be upregulated in patients with focal segmental glomerulosclerosis and mice treated with adriamycin (ADR). In cultured podocytes, transforming growth factor (TGF)-β and ADR were found to promote miR-135a expression. Conversely, TRP channel 1 (TRPC1) protein levels were markedly downregulated in podocytes from mice treated with ADR, as well as in cultured podocytes treated with ADR and TGF-β. Ectopic expression of miR-135a led to severe podocyte injury and disarray of the podocyte cytoskeleton, whereas podocyte-specific expression of TRPC1 was able to reverse the pathological effects of miR-135a in cultured podocytes. Moreover, using Luciferase reporter assays and western blot analysis, TRPC1 was identified as a target gene of miR-135a. To the best of our knowledge, this is the first study to demonstrate the role of TRPC1 in the development of podocyte injury and disorders of the podocyte cytoskeleton, which may contribute to the development of novel therapeutics for podocyte injury-associated kidney diseases.
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Affiliation(s)
- Xianggui Yang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chengdu Medical University, Chengdu, Sichuan 610500, P.R. China
| | - Dongming Wu
- Department of Laboratory Medicine, The First Affiliated Hospital of Chengdu Medical University, Chengdu, Sichuan 610500, P.R. China
| | - Hongfei Du
- Department of Laboratory Medicine, The First Affiliated Hospital of Chengdu Medical University, Chengdu, Sichuan 610500, P.R. China
| | - Fang Nie
- Department of Laboratory Medicine, The First Affiliated Hospital of Chengdu Medical University, Chengdu, Sichuan 610500, P.R. China
| | - Xueli Pang
- Department of Laboratory Medicine, The First Affiliated Hospital of Chengdu Medical University, Chengdu, Sichuan 610500, P.R. China
| | - Ying Xu
- Department of Laboratory Medicine, The First Affiliated Hospital of Chengdu Medical University, Chengdu, Sichuan 610500, P.R. China
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Liu Y, Zhang J, Wang Y, Zeng X. Apelin involved in progression of diabetic nephropathy by inhibiting autophagy in podocytes. Cell Death Dis 2017; 8:e3006. [PMID: 28837139 PMCID: PMC5596593 DOI: 10.1038/cddis.2017.414] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 07/17/2017] [Accepted: 07/19/2017] [Indexed: 12/25/2022]
Abstract
Podocyte autophagy dysfunction has been reported to be responsible for the progression of diabetic nephropathy (DN), however, the factors contributed to autophagy dysfunction in type 2 diabetes are not fully understood. Among promoting factors in DN, an adipokine, apelin, had been showed to trigger podocyte dysfunction. Therefore, it is hypothesized that apelin, which is increased in plasma in type 2 diabetes, lead to podocyte apoptosis through inhibiting podocyte autophagy, which resulted in podocyte dysfunction followed by DN. KkAy mice (diabetic mice) and cultured podocytes (MPC5 cells and native podocytes) were treated with high glucose (HG) and apelin or its antagonist F13A. Renal function, podocyte autophagy, podocyte apoptosis and corresponding cell signaling pathways in podocytes were detected. The results showed that apelin aggravated the renal dysfunction and foot process injuries in kkAy mice, which is positively correlated to podocyte apoptosis and negatively correlated to podocyte autophagy. Apelin induced podocyte apoptosis and inhibited podocyte autophagy in both normal glucose and HG conditions while F13A reversed these effects. Investigations by western blot found that apelin inhibits podocyte autophagy through ERK-, Akt- and mTOR-dependent pathways. In conclusion, increased apelin concentration in plasma inhibited podocyte autophagy, which would lead to podocyte apoptosis and renal dysfunction in diabetes. These effects would contribute to the progression of DN.
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Affiliation(s)
- Yu Liu
- Department of Pathology and Pathophysiology, Basic Medical School of Capital Medical University, Beijing 100069, China
| | - Jia Zhang
- Department of Pathology and Pathophysiology, Basic Medical School of Capital Medical University, Beijing 100069, China
| | - Yangjia Wang
- Department of Pathology and Pathophysiology, Basic Medical School of Capital Medical University, Beijing 100069, China
| | - Xiangjun Zeng
- Department of Pathology and Pathophysiology, Basic Medical School of Capital Medical University, Beijing 100069, China
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Mikulak J, Oriolo F, Portale F, Tentorio P, Lan X, Saleem MA, Skorecki K, Singhal PC, Mavilio D. Impact of APOL1 polymorphism and IL-1β priming in the entry and persistence of HIV-1 in human podocytes. Retrovirology 2016; 13:63. [PMID: 27599995 PMCID: PMC5011791 DOI: 10.1186/s12977-016-0296-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/16/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Patients of African ancestry with untreated HIV-1 infection and carrying the G1 or G2 kidney disease risk variants (Vs) at the APOL1 gene have a tenfold higher risk of developing HIV-associated nephropathy (HIVAN) compared to those with the non-risk wild type (WT) G0 variant. However, the mechanistic contribution of the APOL1 allelic state to kidney injury in HIV-1 infection remains to be elucidated. RESULTS Non-risk WT APOL1 is associated with lower intracellular levels of HIV-1 in conditionally immortalized human podocytes, while the over expression of G1 or G2 risk Vs significantly increases viral accumulation. The priming of podocytes with exogenous IL-1β facilitates HIV-1 entry, via the up-regulation of DC-SIGN. The over expression of APOL1 G1 and G2 risk Vs in combination with an increase in IL-1β levels causes a greater increase in viral concentration than either condition alone. In turn, HIV-1 and exogenous IL-1β together induce a de novo secretion of endogenous IL-1β and an increase of APOL1 gene expression. CONCLUSIONS Our findings indicate that the presence of risk Vs of APOL1 is permissive of HIV-1 persistence in human podocytes in synergy with IL-1β, a cytokine that characterizes the inflammatory milieu of acute and chronic phases of HIV-1 infection. The elucidation of these molecular mechanisms explains, at least in part, the higher frequency of HIVAN in populations carrying the risk polymorphic genetic variant of APOL1 gene.
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Affiliation(s)
- Joanna Mikulak
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy. .,Istituto di Ricerca Genetica e Biomedica, UOS di Milano, Consiglio Nazionale delle Ricerche (UOS/IRGB/CNR), Rozzano, Milan, Italy.
| | - Ferdinando Oriolo
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
| | - Federica Portale
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
| | - Paolo Tentorio
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy
| | - Xiqian Lan
- Center for Excellence for Immunology and Inflammation, Feinstein Institute for Medical Research, Hofstra North Shore Long Island Jewish Medical School, New Hyde Park, NY, USA
| | - Moin A Saleem
- Children's Renal Unit and Academic Renal Unit, University of Bristol, Bristol, UK
| | - Karl Skorecki
- Nephrology and Molecular Medicine, Technion Institute of Technology and Rambam Medical Center, Haifa, Israel
| | - Pravin C Singhal
- Center for Excellence for Immunology and Inflammation, Feinstein Institute for Medical Research, Hofstra North Shore Long Island Jewish Medical School, New Hyde Park, NY, USA
| | - Domenico Mavilio
- Unit of Clinical and Experimental Immunology, Humanitas Clinical and Research Center, Rozzano, Milan, Italy. .,Department of Medical Biotechnologies and Translational Medicine (BioMeTra), University of Milan, Milan, Italy.
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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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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: 43] [Impact Index Per Article: 5.4] [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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11
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Pudur S, Srivastava T, Sharma M, Sharma R, Tarima S, Dai H, McCarthy ET, Savin VJ. Serum glomerular albumin permeability activity: association with rapid progression to end-stage renal disease in focal segmental glomerulosclerosis. SPRINGERPLUS 2016; 5:432. [PMID: 27104120 PMCID: PMC4828406 DOI: 10.1186/s40064-016-2077-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 03/30/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND Focal segmental glomerulosclerosis (FSGS) is a major cause of renal failure. Sera of some FSGS patients increase glomerular albumin permeability (Palb) during in vitro testing and cause proteinuria in experimental animals. OBJECTIVES To determine whether permeability activity of FSGS serum (Palb activity) is associated with rate of progression to renal replacement therapy (RRT). DESIGN This is an observational study based on medical and demographic information and Palb activity testing. SETTING Studies were performed at Medical College of Wisconsin. PATIENTS Serum was submitted by patients' nephrologists for measurement of Palb activity. Each patient had had a biopsy diagnosis of FSGS, had reached ESRD and was on dialysis or had a functioning transplant. MEASUREMENTS Palb activity, clinical characteristics and time between biopsy diagnosis and RRT (T-RRT) were recorded for each patient. METHODS Palb activity was measured using established in vitro techniques. RESULTS Palb and T-RRT were inversely correlated. Neither Palb nor T-RRT varied with demographics or medications. Kaplan-Meier survival curves showed that patients with Palb ≥ 0.5 progressed to RRT more rapidly than others. LIMITATIONS Only patients who had reached RRT were included. Limited clinical information was available for each patient. Central verification of biopsy characteristics was not performed and detailed descriptions of renal histology were not available. CONCLUSIONS Palb activity is associated with the rate of progression to RRT in patients with FSGS. Additional observations will be needed to verify that Palb activity predicts prognosis and is useful in stratifying patients for clinical decision making or treatment trials.
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Affiliation(s)
| | - Tarak Srivastava
- Section of Nephrology, Children's Mercy Hospital, University of Missouri at Kansas City, 2401 Gillham Road, Kansas City, MO 64108 USA
| | - Mukut Sharma
- Kansas City Veterans Hospital, Kansas City, MO USA
| | - Ram Sharma
- Kansas City Veterans Hospital, Kansas City, MO USA
| | - Sergey Tarima
- Division of Biostatistics, Medical College of Wisconsin, Milwaukee, WI USA
| | - Hongying Dai
- Section of Nephrology, Children's Mercy Hospital, University of Missouri at Kansas City, 2401 Gillham Road, Kansas City, MO 64108 USA
| | - Ellen T McCarthy
- Kidney Institute, University of Kansas Medical Center, Kansas City, KS USA
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12
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Guo C, Liu Y, Zhao W, Wei S, Zhang X, Wang W, Zeng X. Apelin promotes diabetic nephropathy by inducing podocyte dysfunction via inhibiting proteasome activities. J Cell Mol Med 2015; 19:2273-85. [PMID: 26103809 PMCID: PMC4568931 DOI: 10.1111/jcmm.12619] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/15/2015] [Indexed: 12/12/2022] Open
Abstract
Podocyte injuries are associated with progression of diabetic nephropathy (DN). Apelin, an adipocyte-derived peptide, has been reported to be a promoting factor for DN. In this study, we aim to determine whether apelin promotes progression of DN by inducing podocyte dysfunction. kk-Ay mice were used as models for DN. Apelin and its antagonist, F13A were intraperitoneally administered for 4 weeks, respectively. Renal function and foot process proteins were analysed to evaluate the effects of apelin on kk-Ay mice and podocytes. Apelin increased albuminuria and decreased podocyte foot process proteins expression in kk-Ay mice, which is consistent with the results that apelin receptor (APLNR) levels increased in glomeruli of patients or mice with DN. In cultured podocytes, high glucose increased APLNR expression and apelin administration was associated with increased permeability and decreased foot process proteins levels. All these dysfunctions were associated with decreased 26S proteasome activities and increased polyubiquitinated proteins in both kk-Ay mice and cultured podocytes, as demonstrated by 26S proteasome activation with cyclic adenosine monophosphate (cAMP) or oleuropein. These effects seemed to be related to endoplasmic reticulum (ER) stress, as apelin increased C/EBP homologous protein (CHOP) and peiFα levels while cAMP or oleuropein reduced it in high glucose and apelin treated podocytes. These results suggest that apelin induces podocyte dysfunction in DN through ER stress which was induced by decreased proteasome activities in podocytes.
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Affiliation(s)
- Caixia Guo
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China.,Department of Cardiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yu Liu
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Wenjie Zhao
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Shengnan Wei
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Xiaoli Zhang
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
| | - Wenying Wang
- Department of Urology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Xiangjun Zeng
- Department of Pathophysiology and Pathology, Capital Medical University, Beijing, China
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13
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Jinks RN, Puffenberger EG, Baple E, Harding B, Crino P, Fogo AB, Wenger O, Xin B, Koehler AE, McGlincy MH, Provencher MM, Smith JD, Tran L, Al Turki S, Chioza BA, Cross H, Harlalka GV, Hurles ME, Maroofian R, Heaps AD, Morton MC, Stempak L, Hildebrandt F, Sadowski CE, Zaritsky J, Campellone K, Morton DH, Wang H, Crosby A, Strauss KA. Recessive nephrocerebellar syndrome on the Galloway-Mowat syndrome spectrum is caused by homozygous protein-truncating mutations of WDR73. Brain 2015; 138:2173-90. [PMID: 26070982 PMCID: PMC4511861 DOI: 10.1093/brain/awv153] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/14/2015] [Indexed: 12/20/2022] Open
Abstract
Galloway-Mowat syndrome (GMS) is a neurodevelopmental disorder characterized by microcephaly, cerebellar hypoplasia, nephrosis, and profound intellectual disability. Jinks et al. extend the GMS spectrum by identifying a novel nephrocerebellar syndrome with selective striatal cholinergic interneuron loss and complete lateral geniculate nucleus delamination, caused by a frameshift mutation in WDR73. We describe a novel nephrocerebellar syndrome on the Galloway-Mowat syndrome spectrum among 30 children (ages 1.0 to 28 years) from diverse Amish demes. Children with nephrocerebellar syndrome had progressive microcephaly, visual impairment, stagnant psychomotor development, abnormal extrapyramidal movements and nephrosis. Fourteen died between ages 2.7 and 28 years, typically from renal failure. Post-mortem studies revealed (i) micrencephaly without polymicrogyria or heterotopia; (ii) atrophic cerebellar hemispheres with stunted folia, profound granule cell depletion, Bergmann gliosis, and signs of Purkinje cell deafferentation; (iii) selective striatal cholinergic interneuron loss; and (iv) optic atrophy with delamination of the lateral geniculate nuclei. Renal tissue showed focal and segmental glomerulosclerosis and extensive effacement and microvillus transformation of podocyte foot processes. Nephrocerebellar syndrome mapped to 700 kb on chromosome 15, which contained a single novel homozygous frameshift variant (WDR73 c.888delT; p.Phe296Leufs*26). WDR73 protein is expressed in human cerebral cortex, hippocampus, and cultured embryonic kidney cells. It is concentrated at mitotic microtubules and interacts with α-, β-, and γ-tubulin, heat shock proteins 70 and 90 (HSP-70; HSP-90), and the carbamoyl phosphate synthetase 2/aspartate transcarbamylase/dihydroorotase multi-enzyme complex. Recombinant WDR73 p.Phe296Leufs*26 and p.Arg256Profs*18 proteins are truncated, unstable, and show increased interaction with α- and β-tubulin and HSP-70/HSP-90. Fibroblasts from patients homozygous for WDR73 p.Phe296Leufs*26 proliferate poorly in primary culture and senesce early. Our data suggest that in humans, WDR73 interacts with mitotic microtubules to regulate cell cycle progression, proliferation and survival in brain and kidney. We extend the Galloway-Mowat syndrome spectrum with the first description of diencephalic and striatal neuropathology.
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Affiliation(s)
- Robert N Jinks
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA
| | - Erik G Puffenberger
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA 2 Clinic for Special Children, Strasburg, PA 17579, USA
| | - Emma Baple
- 3 RILD Wellcome Wolfson Centre, Royal Devon and Exeter NHS Foundation Trust, Barrack Road, Exeter, EX2 5DW, UK 4 Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, UK 5 Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton, UK
| | - Brian Harding
- 6 Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Peter Crino
- 7 Shriners Hospital Paediatric Research Centre, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Agnes B Fogo
- 8 Division of Renal Pathology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Olivia Wenger
- 9 New Leaf Clinic for Special Children, Mount Eaton, OH 44659, USA 10 Department of Paediatrics, Akron Children's Hospital, Akron, OH 44302, USA
| | - Baozhong Xin
- 11 DDC Clinic for Special Needs Children, Middlefield, OH 44062, USA
| | - Alanna E Koehler
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA
| | - Madeleine H McGlincy
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA
| | - Margaret M Provencher
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA
| | - Jeffrey D Smith
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA
| | - Linh Tran
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA
| | - Saeed Al Turki
- 12 Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Barry A Chioza
- 13 Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter EX1 2LU, UK
| | - Harold Cross
- 14 Department of Ophthalmology, University of Arizona College of Medicine, Tucson, AZ 85711, USA
| | - Gaurav V Harlalka
- 13 Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter EX1 2LU, UK
| | - Matthew E Hurles
- 12 Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Reza Maroofian
- 13 Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter EX1 2LU, UK
| | - Adam D Heaps
- 2 Clinic for Special Children, Strasburg, PA 17579, USA
| | - Mary C Morton
- 2 Clinic for Special Children, Strasburg, PA 17579, USA
| | - Lisa Stempak
- 15 Department of Pathology, University Hospitals Case Medical Centre, Cleveland, OH 44106, USA 16 Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Friedhelm Hildebrandt
- 17 Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA 18 Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Carolin E Sadowski
- 18 Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Joshua Zaritsky
- 19 Department of Paediatrics, Nemours/Alfred I. DuPont Hospital for Children, Wilmington, DE 19803, USA
| | - Kenneth Campellone
- 20 Department of Molecular and Cell Biology and Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - D Holmes Morton
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA 2 Clinic for Special Children, Strasburg, PA 17579, USA 21 Lancaster General Hospital, Lancaster, PA 17602, USA
| | - Heng Wang
- 11 DDC Clinic for Special Needs Children, Middlefield, OH 44062, USA 22 Department of Paediatrics, Rainbow Babies and Children's Hospital and Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Andrew Crosby
- 3 RILD Wellcome Wolfson Centre, Royal Devon and Exeter NHS Foundation Trust, Barrack Road, Exeter, EX2 5DW, UK
| | - Kevin A Strauss
- 1 Department of Biology and Biological Foundations of Behaviour Program, Franklin and Marshall College, Lancaster, PA 17604, USA 2 Clinic for Special Children, Strasburg, PA 17579, USA 21 Lancaster General Hospital, Lancaster, PA 17602, USA
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14
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Label-free quantitative proteomic analysis reveals strong involvement of complement alternative and terminal pathways in human glomerular sclerotic lesions. J Proteomics 2015; 123:89-100. [DOI: 10.1016/j.jprot.2015.03.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 03/02/2015] [Accepted: 03/19/2015] [Indexed: 11/21/2022]
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15
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Zeng C, Fan Y, Wu J, Shi S, Chen Z, Zhong Y, Zhang C, Zen K, Liu Z. Podocyte autophagic activity plays a protective role in renal injury and delays the progression of podocytopathies. J Pathol 2014; 234:203-13. [PMID: 24870816 DOI: 10.1002/path.4382] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 05/10/2014] [Accepted: 05/20/2014] [Indexed: 12/22/2022]
Affiliation(s)
- Caihong Zeng
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Yun Fan
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Junnan Wu
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Shaolin Shi
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Zhaohong Chen
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Yongzhong Zhong
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Changming Zhang
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
| | - Ke Zen
- JERC-MBB, State Key Laboratory of Pharmaceutical Biotechnology; Nanjing University School of Life Sciences; Nanjing Jiangsu 210093 China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases; Jinling Hospital, Nanjing University School of Medicine; Nanjing Jiangsu 210002 China
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16
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Lu W, Liu S, Zhao Z, Liu Y, Li T. The effect of connective tissue growth factor on renal fibrosis and podocyte injury in hypertensive rats. Ren Fail 2014; 36:1420-7. [DOI: 10.3109/0886022x.2014.934692] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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17
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Nagayama Y, Braun GS, Jakobs CM, Maruta Y, van Roeyen CR, Klinkhammer BM, Boor P, Villa L, Raffetseder U, Trautwein C, Görtz D, Müller-Newen G, Ostendorf T, Floege J. Gp130-dependent signaling in the podocyte. Am J Physiol Renal Physiol 2014; 307:F346-55. [PMID: 24899055 DOI: 10.1152/ajprenal.00620.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Renal inflammation, in particular glomerular, is often characterized by increased IL-6 levels. The in vivo relevance of IL-6 signaling in glomerular podocytes, which play central roles in most glomerular diseases, is unknown. Here, we show that in normal mice, podocytes express gp130, the common signal-transducing receptor subunit of the IL-6 family of cytokines. Following systemic IL-6 or LPS injection in mice, podocyte IL-6 signaling was evidenced by downstream STAT3 phosphorylation. Next, we generated mice deficient for gp130 in podocytes. Expectedly, these mice exhibited abrogated IL-6 downstream signaling in podocytes. At the age of 40 wk, they did not show spontaneous renal pathology or abnormal renal function. The mice were then challenged using two LPS injury models as well as nephrotoxic serum to induce crescentic nephritis. Under all conditions, circulating IL-6 levels increased markedly and the mice developed the pathological hallmarks of the corresponding injury models such as proteinuria and development of glomerular crescents, respectively. However, despite the capacity of normal podocytes to transduce IL-6 family signals downstream, there were no significant differences between mice bearing the podocyte-specific gp130 deletion and their control littermates in any of these models. In conclusion, under the different conditions tested, gp130 signaling was not a critical component of the (patho-)biology of the podocyte in vivo.
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Affiliation(s)
- Yoshikuni Nagayama
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany; Division of Nephrology, Showa University Fujigaoka Hospital, Yokohama, Japan
| | - Gerald S Braun
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany; Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany;
| | - Christina M Jakobs
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany
| | - Yuichi Maruta
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany; Division of Nephrology, Showa University Fujigaoka Hospital, Yokohama, Japan
| | | | | | - Peter Boor
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany; Institute of Pathology, RWTH Aachen University, Aachen, Germany; Institute of Molecular Biomedicine, Comenius University, Bratislava, Slovakia; and
| | - Luigi Villa
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany
| | - Ute Raffetseder
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany
| | - Christian Trautwein
- Division of Gastroenterology, Metabolic Diseases, and Intensive Care, RWTH Aachen University, Aachen, Germany
| | - Dieter Görtz
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Gerhard Müller-Newen
- Institute of Biochemistry and Molecular Biology, RWTH Aachen University, Aachen, Germany
| | - Tammo Ostendorf
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany
| | - Jürgen Floege
- Division of Nephrology and Immunology, RWTH Aachen University, Aachen Germany
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Schordan S, Grisk O, Schordan E, Miehe B, Rumpel E, Endlich K, Giebel J, Endlich N. OPN deficiency results in severe glomerulosclerosis in uninephrectomized mice. Am J Physiol Renal Physiol 2013; 304:F1458-70. [PMID: 23552865 DOI: 10.1152/ajprenal.00615.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Osteopontin (OPN) expression has been reported to be elevated in experimental models of renal injury such as arterial hypertension or diabetic nephropathy finally leading to focal segmental glomerulosclerosis (FSGS). FSGS is characterized by glomerular matrix deposition and loss or damage of podocytes that represent the main constituents of the glomerular filtration barrier. To evaluate the role of OPN in the kidney we investigated WT and OPN knockout mice (OPN-/-) without treatment, after uninephrectomy (UNX), as well as after UNX and desoxycorticosterone acetate (DOCA)-salt treatment with respect to urine parameters, glomerular morphology, and expression of podocyte markers. OPN-/- mice showed normal urine parameters while a thickening of the glomerular basement membrane was evident. Intriguingly, following UNX, OPN-/- mice exhibited prominent FSGS, proteinuria, and glomerular matrix deposition. Electron microscopy revealed bulgings of the glomerular basement membrane and occasionally an effacement of podocytes. After UNX and DOCA-salt treatment, severe glomerular lesions as well as proteinuria and albuminuria were seen in WT and OPN-/- mice. Moreover, we found a reduction of specific markers such as Wilm's tumor-1, podocin, and synaptopodin in both experimental groups indicating a loss of podocytes. Podocyte damage was accompanied by increased number of Ki-67-positive cells in the parietal epithelium of Bowman's capsule. We conclude that OPN plays a crucial role in adaptation of podocytes following renal ablation and is renoprotective when glomerular mechanical load is increased.
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Affiliation(s)
- Sandra Schordan
- Department of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Greifswald, Germany
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