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Zhao RB, Xu YS, Li XH, Wei MJ, Deng Y, Peng X, Pan L. Correlation analysis of cofilin-1 with renal prognosis in primary IgA nephropathy. BMC Nephrol 2024; 25:289. [PMID: 39227817 PMCID: PMC11373397 DOI: 10.1186/s12882-024-03723-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Accepted: 08/21/2024] [Indexed: 09/05/2024] Open
Abstract
PURPOSE The purpose of this study was to investigate the correlation between podocyte related biomarker cofilin-1 and renal function, and explore the value of cofilin-1 in predicting the risk of renal adverse prognosis in IgA nephropathy (IgAN). METHODS Patients with primary IgAN diagnosed by initial renal biopsy performed in our hospital from January 2019 to February 2022 were included. This study was a prospective cohort study. All IgAN patients were detected the expression of cofilin-1 and other related biomarkers (RhoA, NGAL) in urine by enzyme-linked immunosorbent assay (ELISA) and follow-up at least 6 months. We also collected baseline clinicopathologial data of IgAN. The decreased renal function group was defined as baseline eGFR < 60 ml/min/1.73m2. Logistic and Cox regression model were used to analyze the correlation among cofilin-1 and renal prognosis. RESULTS 133 IgAN patients were included, with a male-to-female ratio of 1.25:1 and an age of 37.67 ± 13.78 years, as well as an average of eGFR was 71.63 (40.42,109.33) ml/min/1.73m2. 56 patients (42.1%) had decreased renal function at baseline, with the average of eGFR was 34.07 (16.72, 49.21) ml/min/1.73 m2. 12 of which developed to renal adverse prognosis. The average of follow-up time was 22.035 ± 8.992 months. The multivariate regression analysis showed that increased urinary cofilin-1 was an independent risk factor associated with baseline renal function decline and renal adverse prognosis in IgAN patients (P < 0.05). ROC curves showed great efficacy of urinary cofilin-1 levels in diagnosing baseline renal function decline and predicting renal adverse prognosis (the area under the ROC curve was 0.708 and 0.803). CONCLUSION Cofilin-1 as a novel biomarker of podocyte lesion is closely related to renal function decline in IgAN. Cofilin-1 has certain clinical value in predicting the risk of renal adverse prognosis. Podocyte fusion affects the renal prognosis of IgAN.
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Affiliation(s)
- Ruo-Bei Zhao
- Department of Nephrology, The First Affiliated Hospital of Guangxi Medical University, No.6 Shuangyong Road, Nanning City, 530021, Guangxi Province, China
| | - Yuan-Shan Xu
- Department of Nephrology, The First Affiliated Hospital of Guangxi Medical University, No.6 Shuangyong Road, Nanning City, 530021, Guangxi Province, China
| | - Xiao-Hua Li
- Department of Nephrology, The First Affiliated Hospital of Guangxi Medical University, No.6 Shuangyong Road, Nanning City, 530021, Guangxi Province, China
| | - Mei-Ju Wei
- Department of Nephrology, The First Affiliated Hospital of Guangxi Medical University, No.6 Shuangyong Road, Nanning City, 530021, Guangxi Province, China
| | - Yang Deng
- Department of Nephrology, The First Affiliated Hospital of Guangxi Medical University, No.6 Shuangyong Road, Nanning City, 530021, Guangxi Province, China
| | - Xun Peng
- Department of Nephrology, The First Affiliated Hospital of Guangxi Medical University, No.6 Shuangyong Road, Nanning City, 530021, Guangxi Province, China
| | - Ling Pan
- Department of Nephrology, The First Affiliated Hospital of Guangxi Medical University, No.6 Shuangyong Road, Nanning City, 530021, Guangxi Province, China.
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2
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Schindler M, Endlich N. Zebrafish as a model for podocyte research. Am J Physiol Renal Physiol 2024; 326:F369-F381. [PMID: 38205541 DOI: 10.1152/ajprenal.00335.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/25/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
Podocytes, specialized postmitotic cells, are central players in various kidney-related diseases. Zebrafish have become a valuable model system for studying podocyte biology because they are genetically easy to manipulate, transparent, and their glomerular structure is similar to that of mammals. This review provides an overview of the knowledge of podocyte biology in zebrafish larvae, with particular focus on their essential contribution to understanding the mechanisms that underlie kidney diseases as well as supporting drug development. In addition, special attention is given to advances in live-imaging techniques allowing the observation of dynamic processes, including podocyte motility, podocyte process behavior, and glomerulus maturation. The review further addresses the functional aspects of podocytes in zebrafish larvae. This includes topics such as glomerular filtration, ultrastructural analyses, and evaluation of podocyte response to nephrotoxic insults. Studies presented in this context have provided important insights into the maintenance and resistance of the glomerular filtration barrier in zebrafish larvae and explored the potential transferability of these findings to mammals such as mice, rats, and most importantly, humans. The recent ability to identify potential therapeutic targets represents a promising new way to identify drugs that could effectively treat podocyte-associated glomerulopathies in humans. In summary, this review gives an overview about the importance of zebrafish as a model for podocyte-related disease and targeted drug development. It also highlights the key role of advanced imaging techniques in transparent zebrafish larvae, improving our understanding of glomerular diseases and the significant potential for translation of these findings to humans.
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Affiliation(s)
- Maximilian Schindler
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Greifswald, Germany
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3
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Li T, Liu TC, Liu N, Li MJ, Zhang M. Urinary exosome proteins PAK6 and EGFR as noninvasive diagnostic biomarkers of diabetic nephropathy. BMC Nephrol 2023; 24:291. [PMID: 37789280 PMCID: PMC10548700 DOI: 10.1186/s12882-023-03343-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 09/21/2023] [Indexed: 10/05/2023] Open
Abstract
OBJECTIVE The actin cytoskeleton plays an essential role in maintaining podocyte functions. However, whether the urinary exosome proteins related to the regulation of the actin cytoskeleton are changed in diabetic nephropathy (DN) is still unknown. This study was to investigate the possibility that related proteins can be applied as diagnostic biomarkers for DN. METHODS Urinary exosomes were obtained from 144 participants (Discovery phase: n = 72; Validation phase: n = 72) by size exclusion chromatography methods. Proteomic analysis of urinary exosome by LC-MS/MS. Western blot and ELISA were applied to validate the selected urinary exosome proteins. The clinical value of selected urinary exosome proteins was evaluated using correlation and receiver operating characteristic curve analyses. RESULTS Fifteen urinary proteins related to the regulation of the actin cytoskeleton were identified in urinary exosomes. Three upregulated proteins were selected, including Serine/threonine-protein kinase PAK6 (PAK6), Epidermal growth factor receptor (EGFR), and SHC-transforming protein 1(SHC1). The expression level of PAK6 and EGFR was negatively correlated with estimated glomerular filtration rate and positively correlated with serum creatinine levels. For diagnosing DN in the discovery phase: the area under curve (AUC) of PAK6 was 0.903, EGFR was 0.842, and the combination of two proteins was 0.912. These better performances were also observed in the validation phase (For PAK6: AUC = 0.829; For EGFR: AUC = 0.797; For PAK6 + EGFR: AUC = 0.897). CONCLUSIONS Urinary exosome proteins PAK6 and EGFR may be promising and noninvasive biomarkers for diagnosing DN.
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Affiliation(s)
- Tao Li
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, 100038, China
| | - Tian Ci Liu
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, 100038, China
| | - Na Liu
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, 100038, China
| | - Meng Jie Li
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, 100038, China
| | - Man Zhang
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China.
- Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, 100038, China.
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4
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Zhang R, Liu Q, Pan S, Zhang Y, Qin Y, Du X, Yuan Z, Lu Y, Song Y, Zhang M, Zhang N, Ma J, Zhang Z, Jia X, Wang K, He S, Liu S, Ni M, Liu X, Xu X, Yang H, Wang J, Seim I, Fan G. A single-cell atlas of West African lungfish respiratory system reveals evolutionary adaptations to terrestrialization. Nat Commun 2023; 14:5630. [PMID: 37699889 PMCID: PMC10497629 DOI: 10.1038/s41467-023-41309-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
The six species of lungfish possess both lungs and gills and are the closest extant relatives of tetrapods. Here, we report a single-cell transcriptome atlas of the West African lungfish (Protopterus annectens). This species manifests the most extreme form of terrestrialization, a life history strategy to survive dry periods that can last for years, characterized by dormancy and reversible adaptive changes of the gills and lungs. Our atlas highlights the cell type diversity of the West African lungfish, including gene expression consistent with phenotype changes of terrestrialization. Comparison with terrestrial tetrapods and ray-finned fishes reveals broad homology between the swim bladder and lung cell types as well as shared and idiosyncratic changes of the external gills of the West African lungfish and the internal gills of Atlantic salmon. The single-cell atlas presented here provides a valuable resource for further exploration of the respiratory system evolution in vertebrates and the diversity of lungfish terrestrialization.
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Affiliation(s)
- Ruihua Zhang
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | - Qun Liu
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
- Department of Biology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Shanshan Pan
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | - Yingying Zhang
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | - Yating Qin
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | - Xiao Du
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
- BGI Research, 518083, Shenzhen, China
| | - Zengbao Yuan
- College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | - Yongrui Lu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, 430072, Wuhan, China
| | - Yue Song
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | | | - Nannan Zhang
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | - Jie Ma
- BGI Research, 266555, Qingdao, China
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China
| | | | - Xiaodong Jia
- Joint Laboratory for Translational Medicine Research, Liaocheng People's Hospital, 252000, Liaocheng, Shandong, P.R. China
| | - Kun Wang
- Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, 710072, Xi'an, China
| | - Shunping He
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, 430072, Wuhan, China
| | - Shanshan Liu
- BGI Research, 518083, Shenzhen, China
- MGI Tech, 518083, Shenzhen, China
| | - Ming Ni
- BGI Research, 518083, Shenzhen, China
- MGI Tech, 518083, Shenzhen, China
| | - Xin Liu
- BGI Research, 518083, Shenzhen, China
| | - Xun Xu
- BGI Research, 518083, Shenzhen, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, 518083, Shenzhen, China
| | | | - Jian Wang
- BGI Research, 518083, Shenzhen, China
| | - Inge Seim
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China.
- School of Biology and Environmental Science, Queensland University of Technology, Brisbane, 4000, Australia.
| | - Guangyi Fan
- BGI Research, 266555, Qingdao, China.
- Qingdao Key Laboratory of Marine Genomics, BGI Research, 266555, Qingdao, China.
- BGI Research, 518083, Shenzhen, China.
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Koehler S, Huber TB, Denholm B. A protective role for <i>Drosophila</i> Filamin in nephrocytes via Yorkie mediated hypertrophy. Life Sci Alliance 2022; 5:e202101281. [PMID: 35922155 PMCID: PMC9351128 DOI: 10.26508/lsa.202101281] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/24/2022] Open
Abstract
Podocytes are specialized epithelial cells of the kidney glomerulus and are an essential part of the filtration barrier. Because of their position, they are exposed to constant biomechanical forces such as shear stress and hydrostatic pressure. These forces increase during disease, resulting in podocyte injury. It is likely podocytes have adaptative responses to help buffer against deleterious mechanical force and thus reduce injury. However, these responses remain largely unknown. Here, using the <i>Drosophila</i> model, we show the mechanosensor Cheerio (dFilamin) provides a key protective role in nephrocytes. We found expression of an activated mechanosensitive variant of Cheerio rescued filtration function and induced compensatory and hypertrophic growth in nephrocytes depleted of the nephrocyte diaphragm proteins Sns or Duf. Delineating the protective pathway downstream of Cheerio we found repression of the Hippo pathway induces nephrocyte hypertrophy, whereas Hippo activation reversed the Cheerio-mediated hypertrophy. Furthermore, we find Yorkie was activated upon expression of active Cheerio. Taken together, our data suggest that Cheerio acts via the Hippo pathway to induce hypertrophic growth, as a protective response in abnormal nephrocytes.
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Affiliation(s)
- Sybille Koehler
- Biomedical Sciences, University of Edinburgh, Edinburgh, UK
- III Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- III Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Barry Denholm
- Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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6
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Jin S, Jeon H, Choe CP. Expression and Functional Analysis of cofilin1-like in Craniofacial Development in Zebrafish. Dev Reprod 2022; 26:23-36. [PMID: 35528320 PMCID: PMC9042393 DOI: 10.12717/dr.2022.26.1.23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/14/2021] [Accepted: 03/09/2021] [Indexed: 11/17/2022]
Abstract
Pharyngeal pouches, a series of outgrowths of the pharyngeal endoderm, are a key
epithelial structure governing facial skeleton development in vertebrates. Pouch
formation is achieved through collective cell migration and rearrangement of
pouch-forming cells controlled by actin cytoskeleton dynamics. While essential
transcription factors and signaling molecules have been identified in pouch
formation, regulators of actin cytoskeleton dynamics have not been reported yet
in any vertebrates. Cofilin1-like (Cfl1l) is a fish-specific member of the
Actin-depolymerizing factor (ADF)/Cofilin family, a critical regulator of actin
cytoskeleton dynamics in eukaryotic cells. Here, we report the expression and
function of cfl1l in pouch development in zebrafish. We first
showed that fish cfl1l might be an ortholog of vertebrate
adf, based on phylogenetic analysis of vertebrate
adf and cfl genes. During pouch formation,
cfl1l was expressed sequentially in the developing pouches
but not in the posterior cell mass in which future pouch-forming cells are
present. However, pouches, as well as facial cartilages whose development is
dependent upon pouch formation, were unaffected by loss-of-function mutations in
cfl1l. Although it could not be completely ruled out a
possibility of a genetic redundancy of Cfl1l with other Cfls, our results
suggest that the cfl1l expression in the developing pouches
might be dispensable for regulating actin cytoskeleton dynamics in pouch-forming
cells.
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Affiliation(s)
- Sil Jin
- Division of Applied Life Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 52828, Korea
| | - Haewon Jeon
- Division of Applied Life Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 52828, Korea
| | - Chong Pyo Choe
- Division of Applied Life Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 52828, Korea.,Division of Life Science, Gyeongsang National University, Jinju 52828, Korea
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7
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Asparaginyl endopeptidase protects against podocyte injury in diabetic nephropathy through cleaving cofilin-1. Cell Death Dis 2022; 13:184. [PMID: 35217650 PMCID: PMC8881581 DOI: 10.1038/s41419-022-04621-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 01/31/2022] [Accepted: 02/08/2022] [Indexed: 11/08/2022]
Abstract
AbstractPodocyte injury and loss are critical events in diabetic nephropathy (DN); however, the underlying molecular mechanisms remain unclear. Here, we demonstrate that asparaginyl endopeptidase (AEP) protects against podocyte injury through modulating the dynamics of the cytoskeleton. AEP was highly upregulated in diabetic glomeruli and hyperglycemic stimuli treated-podocytes; however, AEP gene knockout and its compound inhibitor treatment accelerated DN in streptozotocin-induced diabetic mice, whereas specific induction of AEP in glomerular cells attenuated podocyte injury and renal function deterioration. In vitro, elevated AEP was involved in actin cytoskeleton maintenance and anti-apoptosis effects. Mechanistically, we found that AEP directly cleaved the actin-binding protein cofilin-1 after the asparagine 138 (N138) site. The protein levels of endogenous cofilin-1 1-138 fragments were upregulated in diabetic podocytes, consistent with the changes in AEP levels. Importantly, we found that cofilin-1 1-138 fragments were remarkably unphosphorylated than full-length cofilin-1, indicating the enhanced cytoskeleton maintenance activity of cofilin-1 1-138. Then we validated cofilin-1 1-138 could rescue podocytes from cytoskeleton disarrangement and injury in diabetic conditions. Taken together, our data suggest a protective role of elevated AEP in podocyte injury during DN progression through cleaving cofilin-1 to maintain podocyte cytoskeleton dynamics and defend damage.
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8
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Kim JJ, David JM, Wilbon SS, Santos JV, Patel DM, Ahmad A, Mitrofanova A, Liu X, Mallela SK, Ducasa GM, Ge M, Sloan AJ, Al-Ali H, Boulina M, Mendez AJ, Contreras GN, Prunotto M, Sohail A, Fridman R, Miner JH, Merscher S, Fornoni A. Discoidin domain receptor 1 activation links extracellular matrix to podocyte lipotoxicity in Alport syndrome. EBioMedicine 2020; 63:103162. [PMID: 33340991 PMCID: PMC7750578 DOI: 10.1016/j.ebiom.2020.103162] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 11/21/2020] [Accepted: 11/24/2020] [Indexed: 12/11/2022] Open
Abstract
Background Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase that is activated by collagens that is involved in the pathogenesis of fibrotic disorders. Interestingly, de novo production of the collagen type I (Col I) has been observed in Col4a3 knockout mice, a mouse model of Alport Syndrome (AS mice). Deletion of the DDR1 in AS mice was shown to improve survival and renal function. However, the mechanisms driving DDR1-dependent fibrosis remain largely unknown. Methods Podocyte pDDR1 levels, Collagen and cluster of differentiation 36 (CD36) expression was analyzed by Real-time PCR and Western blot. Lipid droplet accumulation and content was determined using Bodipy staining and enzymatic analysis. CD36 and DDR1 interaction was determined by co-immunoprecipitation. Creatinine, BUN, albuminuria, lipid content, and histological and morphological assessment of kidneys harvested from AS mice treated with Ezetimibe and/or Ramipril or vehicle was performed. Findings We demonstrate that Col I-mediated DDR1 activation induces CD36-mediated podocyte lipotoxic injury. We show that Ezetimibe interferes with the CD36/DDR1 interaction in vitro and prevents lipotoxicity in AS mice thus preserving renal function similarly to ramipril. Interpretation Our study suggests that Col I/DDR1-mediated lipotoxicity contributes to renal failure in AS and that targeting this pathway may represent a new therapeutic strategy for patients with AS and with chronic kidney diseases (CKD) associated with Col4 mutations. Funding This study is supported by the NIH grants R01DK117599, R01DK104753, R01CA227493, U54DK083912, UM1DK100846, U01DK116101, UL1TR000460 (Miami Clinical Translational Science Institute, National Center for Advancing Translational Sciences and the National Institute on Minority Health and Health Disparities), F32DK115109, Hoffmann-La Roche and Alport Syndrome Foundation.
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Affiliation(s)
- Jin-Ju Kim
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States.
| | - Judith M David
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Sydney S Wilbon
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Javier V Santos
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Devang M Patel
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia
| | - Anis Ahmad
- Department of Radiation Oncology, University of Miami, FL 33136, United States
| | - Alla Mitrofanova
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States; Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, United States
| | - Xiaochen Liu
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Shamroop K Mallela
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Gloria M Ducasa
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Mengyuan Ge
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Alexis J Sloan
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Hassan Al-Ali
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Marcia Boulina
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL 33136, United States
| | - Armando J Mendez
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL 33136, United States
| | - Gabriel N Contreras
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Marco Prunotto
- Roche Pharma Research and Early Development, Roche Innovation Center, Basel, Switzerland; School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
| | - Anjum Sohail
- Department of Pathology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Rafael Fridman
- Department of Pathology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Jeffrey H Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Sandra Merscher
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Drug Discovery center, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Ave, Miami, FL 33136, United States.
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9
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Bisphenol A impaired cell adhesion by altering the expression of adhesion and cytoskeleton proteins on human podocytes. Sci Rep 2020; 10:16638. [PMID: 33024228 PMCID: PMC7538920 DOI: 10.1038/s41598-020-73636-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 09/11/2020] [Indexed: 12/12/2022] Open
Abstract
Bisphenol A (BPA), a chemical -xenoestrogen- used in food containers is present in the urine of almost the entire population. Recently, several extensive population studies have proven a significant association between urinary excretion of BPA and albuminuria. The alteration of glomerular podocytes or "podocytopathy" is a common event in chronic albuminuric conditions. Since many podocytes recovered from patients' urine are viable, we hypothesized that BPA could impair podocyte adhesion capabilities. Using an in vitro adhesion assay, we observed that BPA impaired podocyte adhesion, an effect that was abrogated by Tamoxifen (an estrogen receptor blocker). Genomic and proteomic analyses revealed that BPA affected the expression of several podocyte cytoskeleton and adhesion proteins. Western blot and immunocytochemistry confirmed the alteration in the protein expression of tubulin, vimentin, podocin, cofilin-1, vinculin, E-cadherin, nephrin, VCAM-1, tenascin-C, and β-catenin. Moreover, we also found that BPA, while decreased podocyte nitric oxide production, it lead to overproduction of ion superoxide. In conclusion, our data show that BPA induced a novel type of podocytopathy characterizes by an impairment of podocyte adhesion, by altering the expression of adhesion and cytoskeleton proteins. Moreover, BPA diminished production of podocyte nitric oxide and induced the overproduction of oxygen-free metabolites. These data provide a mechanism by which BPA could participate in the pathogenesis and progression of renal diseases.
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10
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Audzeyenka I, Rachubik P, Rogacka D, Typiak M, Kulesza T, Angielski S, Rychłowski M, Wysocka M, Gruba N, Lesner A, Saleem MA, Piwkowska A. Cathepsin C is a novel mediator of podocyte and renal injury induced by hyperglycemia. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118723. [PMID: 32302668 DOI: 10.1016/j.bbamcr.2020.118723] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/08/2020] [Accepted: 04/09/2020] [Indexed: 02/07/2023]
Abstract
A growing body of evidence suggests a role of proteolytic enzymes in the development of diabetic nephropathy. Cathepsin C (CatC) is a well-known regulator of inflammatory responses, but its involvement in podocyte and renal injury remains obscure. We used Zucker rats, a genetic model of metabolic syndrome and insulin resistance, to determine the presence, quantity, and activity of CatC in the urine. In addition to the animal study, we used two cellular models, immortalized human podocytes and primary rat podocytes, to determine mRNA and protein expression levels via RT-PCR, Western blot, and confocal microscopy, and to evaluate CatC activity. The role of CatC was analyzed in CatC-depleted podocytes using siRNA and glycolytic flux parameters were obtained from extracellular acidification rate (ECAR) measurements. In functional analyses, podocyte and glomerular permeability to albumin was determined. We found that podocytes express and secrete CatC, and a hyperglycemic environment increases CatC levels and activity. Both high glucose and non-specific activator of CatC phorbol 12-myristate 13-acetate (PMA) diminished nephrin, cofilin, and GLUT4 levels and induced cytoskeletal rearrangements, increasing albumin permeability in podocytes. These negative effects were completely reversed in CatC-depleted podocytes. Moreover, PMA, but not high glucose, increased glycolytic flux in podocytes. Finally, we demonstrated that CatC expression and activity are increased in the urine of diabetic Zucker rats. We propose a novel mechanism of podocyte injury in diabetes, providing deeper insight into the role of CatC in podocyte biology.
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Affiliation(s)
- Irena Audzeyenka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Gdansk, Poland; Faculty of Chemistry, University of Gdansk, Poland.
| | - Patrycja Rachubik
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Gdansk, Poland
| | - Dorota Rogacka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Gdansk, Poland; Faculty of Chemistry, University of Gdansk, Poland
| | - Marlena Typiak
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Gdansk, Poland
| | - Tomasz Kulesza
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Gdansk, Poland
| | - Stefan Angielski
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Gdansk, Poland
| | - Michał Rychłowski
- Intercollegiate Faculty of Biotechnology, University of Gdansk - Medical University of Gdansk, Poland
| | | | | | - Adam Lesner
- Faculty of Chemistry, University of Gdansk, Poland
| | - Moin A Saleem
- Bristol Renal, University of Bristol, United Kingdom
| | - Agnieszka Piwkowska
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Gdansk, Poland; Faculty of Chemistry, University of Gdansk, Poland
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11
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Shi Y, Wang C, Zhou X, Li Y, Ma Y, Zhang R, Li R. Downregulation of PTEN promotes podocyte endocytosis of lipids aggravating obesity-related glomerulopathy. Am J Physiol Renal Physiol 2020; 318:F589-F599. [PMID: 31813249 DOI: 10.1152/ajprenal.00392.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
With the increasing prevalence of obesity in adults worldwide, the incidence of obesity-related glomerulopathy (ORG) has increased yearly, becoming one of the leading causes of end-stage renal disease. Studies have demonstrated significant correlations between hyperlipidemia and impaired renal function in patients with ORG, indicating that hyperlipidemia causes damage in kidney cells. In podocytes, the endocytosis of lipids triggers an intracellular oxidative stress response that disrupts cellular integrity, resulting in proteinuria and glomerular sclerosis. However, the specific molecular mechanisms through which podocytes endocytose lipids remain unclear. Here, we demonstrated the enhanced endocytosis of lipids by podocytes from patients with ORG. This response was associated with decreased expression of phosphatase and tensin homolog (PTEN). In vitro silencing of PTEN promoted the endocytosis of low-density lipoprotein in mouse podocytes. Conversely, overexpression of PTEN inhibited the endocytosis of lipoproteins in podocytes. PTEN directly dephosphorylates and activates the actin-depolymerizing factor cofilin-1, leading to depolymerization of filamentous actin (F-actin), which is necessary for endocytosis. Notably, inhibition of PTEN resulted in the phosphorylation and inactivation of cofilin-1, leading to F-actin formation that enhanced the endocytosis of lipoproteins in podocytes. When hyperlipidemia was induced in mice with podocyte-specific deletion of PTEN, these mice recapitulated the major pathophysiological features of ORG. Thus, PTEN downregulation in podocytes may contribute to the pathogenesis of ORG.
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Affiliation(s)
- Yuanyuan Shi
- Nephrology Division, The Affiliated People's Hospital of Shanxi Medical University, Taiyuan, China
- Nephrology Division, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Chen Wang
- Pathology Division, Second Hospital of Shanxi Medical University, Taiyuan, China
| | - Xiaoshuang Zhou
- Nephrology Division, The Affiliated People's Hospital of Shanxi Medical University, Taiyuan, China
| | - Yafeng Li
- Nephrology Division, The Affiliated People's Hospital of Shanxi Medical University, Taiyuan, China
| | - Yuehong Ma
- Nephrology Division, The Affiliated People's Hospital of Shanxi Medical University, Taiyuan, China
| | - Rui Zhang
- Nephrology Division, The Affiliated People's Hospital of Shanxi Medical University, Taiyuan, China
| | - Rongshan Li
- Nephrology Division, The Affiliated People's Hospital of Shanxi Medical University, Taiyuan, China
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12
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Mechanical Forces Regulate Cardiomyocyte Myofilament Maturation via the VCL-SSH1-CFL Axis. Dev Cell 2019; 51:62-77.e5. [PMID: 31495694 DOI: 10.1016/j.devcel.2019.08.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/02/2019] [Accepted: 08/07/2019] [Indexed: 01/07/2023]
Abstract
Mechanical forces regulate cell behavior and tissue morphogenesis. During cardiac development, mechanical stimuli from the heartbeat are required for cardiomyocyte maturation, but the underlying molecular mechanisms remain unclear. Here, we first show that the forces of the contracting heart regulate the localization and activation of the cytoskeletal protein vinculin (VCL), which we find to be essential for myofilament maturation. To further analyze the role of VCL in this process, we examined its interactome in contracting versus non-contracting cardiomyocytes and, in addition to several known interactors, including actin regulators, identified the slingshot protein phosphatase SSH1. We show how VCL recruits SSH1 and its effector, the actin depolymerizing factor cofilin (CFL), to regulate F-actin rearrangement and promote cardiomyocyte myofilament maturation. Overall, our results reveal that mechanical forces generated by cardiac contractility regulate cardiomyocyte maturation through the VCL-SSH1-CFL axis, providing further insight into how mechanical forces are transmitted intracellularly to regulate myofilament maturation.
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13
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Müller-Deile J, Schenk H, Niggemann P, Bolaños-Palmieri P, Teng B, Higgs A, Staggs L, Haller H, Schroder P, Schiffer M. Mutation of microphthalmia-associated transcription factor (mitf) in zebrafish sensitizes for glomerulopathy. Biol Open 2019; 8:bio.040253. [PMID: 30718228 PMCID: PMC6451330 DOI: 10.1242/bio.040253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Different glomerular diseases that affect podocyte homeostasis can clinically present as nephrotic syndrome with massive proteinuria, hypoalbuminemia, hyperlipidemia and edema. Up to now, no drugs that specifically target the actin cytoskeleton of podocytes are on the market and model systems for library screenings to develop anti-proteinuric drugs are of high interest. We developed a standardized proteinuria model in zebrafish using puromycin aminonucleoside (PAN) via treatment in the fish water to allow for further drug testing to develop anti-proteinuric drugs for the treatment of glomerular diseases. We noticed that fish that carry the nacre-mutation show a significantly higher susceptibility for the disruption of the glomerular filtration barrier following PAN treatment, which results in a more pronounced proteinuria phenotype. Nacre zebrafish inherit a mutation yielding a truncated version of microphthalmia-associated transcription factor/melanogenesis associated transcription factor (mitf). We hypothesized that the nacre mutation may lead to reduced formin expression and defects in cytoskeletal rearrangement. Based on the observations in zebrafish, we carried out a PAN treatment on cultured human podocytes after knockdown with MITF siRNA causing a rearrangement of the actin cytoskeleton.
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Affiliation(s)
- Janina Müller-Deile
- Department of Nephrology, Hannover Medical School, Hannover 30625, Germany.,Department of Nephrology and Hypertension, University of Erlangen-Nurnberg, Erlangen 91054, Germany
| | - Heiko Schenk
- Department of Nephrology, Hannover Medical School, Hannover 30625, Germany.,Division of Nephrology, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04609, USA
| | - Philipp Niggemann
- Department of Nephrology, Hannover Medical School, Hannover 30625, Germany.,Division of Nephrology, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04609, USA
| | - Patricia Bolaños-Palmieri
- Department of Nephrology, Hannover Medical School, Hannover 30625, Germany.,Department of Nephrology and Hypertension, University of Erlangen-Nurnberg, Erlangen 91054, Germany
| | - Beina Teng
- Department of Nephrology, Hannover Medical School, Hannover 30625, Germany.,Department of Nephrology and Hypertension, University of Erlangen-Nurnberg, Erlangen 91054, Germany
| | - Alysha Higgs
- Division of Nephrology, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04609, USA
| | - Lynne Staggs
- Division of Nephrology, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04609, USA
| | - Hermann Haller
- Department of Nephrology, Hannover Medical School, Hannover 30625, Germany.,Division of Nephrology, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04609, USA
| | - Patricia Schroder
- Division of Nephrology, Mount Desert Island Biological Laboratory, Salisbury Cove, ME 04609, USA
| | - Mario Schiffer
- Department of Nephrology, Hannover Medical School, Hannover 30625, Germany .,Department of Nephrology and Hypertension, University of Erlangen-Nurnberg, Erlangen 91054, Germany
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14
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Yan X, Huang Y, Wu J. Identify Cross Talk Between Circadian Rhythm and Coronary Heart Disease by Multiple Correlation Analysis. J Comput Biol 2018; 25:1312-1327. [PMID: 30234379 DOI: 10.1089/cmb.2017.0254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Disorder in circadian rhythm has been revealed as a risk factor for coronary heart disease. Several studies in molecular biology established a gene interaction network using coronary heart susceptibility genes and the circadian rhythm pathway. However, cross talk between genes was mostly discovered in single gene pairs. There might be combination sets of genes intergraded as a unit to regulate the network. To resolve multiple variables in coronary heart susceptibility genes controlling circadian rhythm pathways, a multiple correlation analysis was applied to the transcriptome. Nine genes, including CUGBP, Elav-like family member (CELF); sodium leak channel, nonselective (NALCN); protein phosphatase 2 regulatory subunit B gamma (PPP2R2C); tubulin alpha 1c (TUBA1C); microtubule-associated protein 4 (MAP4); cofilin 1 (CFL1); myosin heavy chain 7 (MYH7); QKI, KH domain containing RNA binding (QKI); and maternal embryonic leucine zipper kinase (MELK), from coronary heart susceptibility were identified to predict the outcome of a linear combination of circadian rhythm pathway genes with R factor more than 0.7. G protein subunit alpha o1 (GNAO1), protein kinase C gamma (PRKCG), RBX, and G protein subunit beta 1 (GNB1) in the circadian rhythm pathway are characterized as combination variables to coexpress with coronary heart susceptibility genes.
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Affiliation(s)
- Xiaoping Yan
- 1 Department of Cardiology, Fujian Medical University Union Hospital, Fujian Institute of Coronary Heart Disease, Fuzhou, Fujian, China
| | - Yu Huang
- 1 Department of Cardiology, Fujian Medical University Union Hospital, Fujian Institute of Coronary Heart Disease, Fuzhou, Fujian, China
| | - Jiabin Wu
- 2 Department of Nephrology, Fujian Provincial Hospital, Fujian Medical University , Fuzhou, China
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15
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Yu SMW, Nissaisorakarn P, Husain I, Jim B. Proteinuric Kidney Diseases: A Podocyte's Slit Diaphragm and Cytoskeleton Approach. Front Med (Lausanne) 2018; 5:221. [PMID: 30255020 PMCID: PMC6141722 DOI: 10.3389/fmed.2018.00221] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/18/2018] [Indexed: 01/19/2023] Open
Abstract
Proteinuric kidney diseases are a group of disorders with diverse pathological mechanisms associated with significant losses of protein in the urine. The glomerular filtration barrier (GFB), comprised of the three important layers, the fenestrated glomerular endothelium, the glomerular basement membrane (GBM), and the podocyte, dictates that disruption of any one of these structures should lead to proteinuric disease. Podocytes, in particular, have long been considered as the final gatekeeper of the GFB. This specialized visceral epithelial cell contains a complex framework of cytoskeletons forming foot processes and mediate important cell signaling to maintain podocyte health. In this review, we will focus on slit diaphragm proteins such as nephrin, podocin, TRPC6/5, as well as cytoskeletal proteins Rho/small GTPases and synaptopodin and their respective roles in participating in the pathogenesis of proteinuric kidney diseases. Furthermore, we will summarize the potential therapeutic options targeting the podocyte to treat this group of kidney diseases.
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Affiliation(s)
- Samuel Mon-Wei Yu
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States
| | | | - Irma Husain
- Department of Medicine, James J. Peters VA Medical Center, Bronx, NY, United States
| | - Belinda Jim
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States.,Renal Division, Jacobi Medical Center, Bronx, NY, United States
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16
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Regulation of cofilin phosphorylation in glomerular podocytes by testis specific kinase 1 (TESK1). Sci Rep 2018; 8:12286. [PMID: 30115939 PMCID: PMC6095849 DOI: 10.1038/s41598-018-30115-3] [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: 10/11/2017] [Accepted: 07/20/2018] [Indexed: 12/14/2022] Open
Abstract
Expression of a constitutively active Rho A (V14Rho) in podocytes in vivo induces albuminuria and foot process (FP) effacement. These effects may be mediated by the Rho A effector Rho kinase (ROK); but inhibition of ROK with Y27632 failed to attenuate albuminuria or FP effacement in V14Rho mice. ROK activates LIM kinases (LIMKs), which phosphorylate and inhibit the actin depolymerizing factor cofilin 1 (CFL1). Sustained phosphorylation of CFL1 is implicated in human nephrotic diseases, but Y27632 did not inhibit phosphorylation of CFL1 in vivo, despite effective ROK inhibition. CFL1 is also phosphorylated by testis-specific kinase 1 (TESK1) on the same serine residue. TESK1 was expressed in podocytes, and, similar to the in vivo situation, Y27632 had little effect on phospho-CFL1 (pCFL1) levels in cultured podocytes. In contrast, Y27632 reduced pCFL1 levels in TESK1 knockout (KO) cells. ROK inhibition enhanced podocyte motility but, the motility promoting effect of Y27632 was absent in TESK1 KO podocytes. Thus, TESK1 regulates podocyte cytoskeletal dynamics in glomerular podocytes and may play an important role in regulating glomerular filtration barrier integrity in glomerular disease processes.
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17
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Actin dynamics at focal adhesions: a common endpoint and putative therapeutic target for proteinuric kidney diseases. Kidney Int 2018; 93:1298-1307. [PMID: 29678354 DOI: 10.1016/j.kint.2017.12.028] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 12/07/2017] [Accepted: 12/13/2017] [Indexed: 01/02/2023]
Abstract
Proteinuria encompasses diverse causes including both genetic diseases and acquired forms such as diabetic and hypertensive nephropathy. The basis of proteinuria is a disturbance in size selectivity of the glomerular filtration barrier, which largely depends on the podocyte: a terminally differentiated epithelial cell type covering the outer surface of the glomerulus. Compromised podocyte structure is one of the earliest signs of glomerular injury. The phenotype of diverse animal models and podocyte cell culture firmly established the essential role of the actin cytoskeleton in maintaining functional podocyte structure. Podocyte foot processes, actin-based membrane extensions, contain 2 molecularly distinct "hubs" that control actin dynamics: a slit diaphragm and focal adhesions. Although loss of foot processes encompasses disassembly of slit diaphragm multiprotein complexes, as long as cells are attached to the glomerular basement membrane, focal adhesions will be the sites in which stress due to filtration flow is counteracted by forces generated by the actin network in foot processes. Numerous studies within last 20 years have identified actin binding and regulatory proteins as well as integrins as essential components of signaling and actin dynamics at focal adhesions in podocytes, suggesting that some of them may become novel, druggable targets for proteinuric kidney diseases. Here we review evidence supporting the idea that current treatments for chronic kidney diseases beneficially and directly target the podocyte actin cytoskeleton associated with focal adhesions and suggest that therapeutic reagents that target the focal adhesion-regulated actin cytoskeleton in foot processes have potential to modernize treatments for chronic kidney diseases.
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18
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Shin M, Chavez MB, Ikeda A, Foster BL, Bartlett JD. MMP20 Overexpression Disrupts Molar Ameloblast Polarity and Migration. J Dent Res 2018; 97:820-827. [PMID: 29481294 DOI: 10.1177/0022034518758657] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ameloblasts responsible for enamel formation express matrix metalloproteinase 20 (MMP20), an enzyme that cleaves enamel matrix proteins, including amelogenin (AMELX) and ameloblastin (AMBN). Previously, we showed that continuously erupting incisors from transgenic mice overexpressing active MMP20 had a massive cell infiltrate present within their enamel space, leading to enamel mineralization defects. However, effects of MMP20 overexpression on mouse molars were not analyzed, although these teeth more accurately represent human odontogenesis. Therefore, MMP20-overexpressing mice ( Mmp20+/+Tg+) were assessed by multiscale analyses, combining several approaches from high-resolution micro-computed tomography to enamel organ immunoblots. During the secretory stage at postnatal day 6 (P6), Mmp20+/+Tg+ mice had a discontinuous ameloblast layer and, unlike incisors, molar P12 maturation stage ameloblasts abnormally migrated away from the enamel layer into the stratum intermedium/stellate reticulum. TOPflash assays performed in vitro demonstrated that MMP20 expression promoted β-catenin nuclear localization and that MMP20 expression promoted invasion through Matrigel-coated filters. However, for both assays, significant differences were eliminated in the presence of the β-catenin inhibitor ICG-001. This suggests that MMP20 activity promotes cell migration via the Wnt pathway. In vivo, the unique molar migration of amelogenin-expressing ameloblasts was associated with abnormal deposition of ectopic calcified nodules surrounding the adherent enamel layer. Enamel content was assessed just prior to eruption at P15. Compared to wild-type, Mmp20+/+Tg+ molars exhibited significant reductions in enamel thickness (70%), volume (60%), and mineral density (40%), and MMP20 overexpression resulted in premature cleavage of AMBN, which likely contributed to the severe defects in enamel mineralization. In addition, Mmp20+/+Tg+ mouse molar enamel organs had increased levels of inactive p-cofilin, a protein that regulates cell polarity. These data demonstrate that increased MMP20 activity in molars causes premature degradation of ameloblastin and inactivation of cofilin, which may contribute to pathological Wnt-mediated cell migration away from the enamel layer.
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Affiliation(s)
- M Shin
- 1 Fukuoka Dental College, Sawara-ku, Fukuoka, Japan
| | - M B Chavez
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - A Ikeda
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - B L Foster
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - J D Bartlett
- 2 Division of Biosciences, College of Dentistry, The Ohio State University, Columbus, OH, USA
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19
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Rogg M, Yasuda-Yamahara M, Abed A, Dinse P, Helmstädter M, Conzelmann AC, Frimmel J, Sellung D, Biniossek ML, Kretz O, Grahammer F, Schilling O, Huber TB, Schell C. The WD40-domain containing protein CORO2B is specifically enriched in glomerular podocytes and regulates the ventral actin cytoskeleton. Sci Rep 2017; 7:15910. [PMID: 29162887 PMCID: PMC5698439 DOI: 10.1038/s41598-017-15844-1] [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: 09/05/2017] [Accepted: 10/31/2017] [Indexed: 11/13/2022] Open
Abstract
Podocytes are highly specialized epithelial cells essentially required to establish and maintain the kidney filtration barrier. Due to their complex cellular architecture these cells rely on an elaborated cytoskeletal apparatus providing plasticity as well as adaptive adhesion properties to withstand significant physical filtration forces. However, our knowledge about podocyte specific components of the cytoskeletal machinery is still incomplete. Employing cross-analysis of various quantitative omics-data sets we identify the WD40-domain containing protein CORO2B as a podocyte enriched protein. Furthermore, we demonstrate the distinct localization pattern of CORO2B to the ventral actin cytoskeleton serving as a physical linkage module to cell-matrix adhesion sites. Analysis of a novel Coro2b knockout mouse revealed that CORO2B modulates stress response of podocytes in an experimental nephropathy model. Using quantitative focal adhesome proteomics we identify the recruitment of CFL1 via CORO2B to focal adhesions as an underlying mechanism. Thus, we describe CORO2B as a novel podocyte enriched protein influencing cytoskeletal plasticity and stress adaptation.
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Affiliation(s)
- M Rogg
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - M Yasuda-Yamahara
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Department of Medicine, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - A Abed
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - P Dinse
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - M Helmstädter
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - A C Conzelmann
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - J Frimmel
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - D Sellung
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - M L Biniossek
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany
| | - O Kretz
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute of Anatomy and Cell Biology, Dept. for Neuroanatomy, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - F Grahammer
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - O Schilling
- Institute of Molecular Medicine and Cell Research, University of Freiburg, Freiburg, Germany.,BIOSS Center for Biological Signalling Studies and Center for Systems Biology (ZBSA), Albert-Ludwigs-University, Freiburg, Germany.,German Cancer Consortium (DKTK) and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - T B Huber
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany. .,III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. .,BIOSS Center for Biological Signalling Studies and Center for Systems Biology (ZBSA), Albert-Ludwigs-University, Freiburg, Germany.
| | - C Schell
- Department of Medicine IV, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Institute for Surgical Pathology, Medical Center Freiburg, Freiburg, Germany.,Berta-Ottenstein Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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20
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Endlich K, Kliewe F, Endlich N. Stressed podocytes-mechanical forces, sensors, signaling and response. Pflugers Arch 2017; 469:937-949. [PMID: 28687864 DOI: 10.1007/s00424-017-2025-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 02/07/2023]
Abstract
Increased glomerular capillary pressure (glomerular hypertension) and increased glomerular filtration rate (glomerular hyperfiltration) have been proven to cause glomerulosclerosis in animal models and are likely to be operative in patients. Since podocytes cover the glomerular basement membrane, they are exposed to tensile stress due to circumferential wall tension and to fluid shear stress arising from filtrate flow through the narrow filtration slits and through Bowman's space. In vitro evidence documents that podocytes respond to tensile stress as well as to fluid shear stress. Several proteins are discussed in this review that are expressed in podocytes and could act as mechanosensors converting mechanical force via a conformational change into a biochemical signal. The cation channels P2X4 and TRPC6 were shown to be involved in mechanosignaling in podocytes. P2X4 is activated by stretch-induced ATP release, while TRPC6 might be inherently mechanosensitive. Membrane, slit diaphragm and cell-matrix contact proteins are connected to the sublemmal actin network in podocytes via various linker proteins. Therefore, actin-associated proteins, like the proven mechanosensor filamin, are ideal candidates to sense forces in the podocyte cytoskeleton. Furthermore, podocytes express talin, p130Cas, and fibronectin that are known to undergo a conformational change in response to mechanical force exposing cryptic binding sites. Downstream of mechanosensors, experimental evidence suggests the involvement of MAP kinases, Ca2+ and COX2 in mechanosignaling and an emerging role of YAP/TAZ. In summary, our understanding of mechanotransduction in podocytes is still sketchy, but future progress holds promise to identify targets to alleviate conditions of increased mechanical load.
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Affiliation(s)
- Karlhans Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17489, Greifswald, Germany.
- Institut für Anatomie and Zellbiologie, Universitätsmedizin Greifswald, Friedrich-Loeffler-Str. 23c, 17489, Greifswald, Germany.
| | - Felix Kliewe
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17489, Greifswald, Germany
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17489, Greifswald, Germany
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21
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Abstract
Podocytes, the postmitotic and highly branched epithelial cells of the glomerulus, play a pivotal role for the function of the glomerular filtration barrier and the development of chronic kidney disease. It has long been discussed whether podocytes in vivo are motile and can laterally migrate in a coordinated way along the capillaries until they reach the position of naked glomerular basement membrane often found in podocytopathies. Such motility would also be the prerequisite for the replacement of lost podocytes by progenitor cells. Additionally, the change of the podocyte foot processes from a normal to an effaced morphology, like it is found in many kidney diseases, would require a dynamic behavior of podocytes. Since the actin cytoskeleton is expressed in podocytes in vitro and in vivo and the morphology of podocytes is highly dependent on actin, actin-associated, and actin-regulating proteins, it was assumed that podocytes are dynamic and motile. After earlier technical limitations had been overcome and novel microscopic techniques like multiphoton microscopy had been developed, it became possible to continuously study the behavior of podocytes in living rodents and zebrafish larvae under physiological and pathological conditions. Recent in vivo microscopic studies in different model organisms suggest that lateral migration of podocytes in situ is a very unlikely event and only dynamic apical cell protrusions can be observed under pathological conditions. This review discusses recent findings concerning different forms of motility (like lateral translocative (LTM), apical translocative (ATM), and stationary motility (SM)) and their role for podocytopathies.
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Affiliation(s)
- Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17487, Greifswald, Germany. .,Institut für Anatomie und Zellbiologie, Universitätsmedizin Greifswald, Friedrich-Loeffler-Str. 23c, 17487, Greifswald, Germany.
| | - Florian Siegerist
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17487, Greifswald, Germany
| | - Karlhans Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, 17487, Greifswald, Germany
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Siegerist F, Zhou W, Endlich K, Endlich N. 4D in vivo imaging of glomerular barrier function in a zebrafish podocyte injury model. Acta Physiol (Oxf) 2017; 220:167-173. [PMID: 27414464 DOI: 10.1111/apha.12754] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 06/27/2016] [Accepted: 07/10/2016] [Indexed: 01/15/2023]
Abstract
AIM Zebrafish larvae with their simplified pronephros are an ideal model to study glomerular physiology. Although several groups use zebrafish larvae to assess glomerular barrier function, temporary or slight changes are still difficult to measure. The aim of this study was to investigate the potential of in vivo two-photon microscopy (2-PM) for long-term imaging of glomerular barrier function in zebrafish larvae. METHODS As a proof of principle, we adapted the nitroreductase/metronidazole model of targeted podocyte ablation for 2-PM. Combination with a strain, which expresses eGFP-vitamin D-binding protein in the blood plasma, led to a strain that allowed induction of podocyte injury with parallel assessment of glomerular barrier function. We used four-dimensional (4D) 2-PM to assess eGFP fluorescence over 26 h in the vasculature and in tubules of multiple zebrafish larvae (5 days post-fertilization) simultaneously. RESULTS By 4D 2-PM, we observed that, under physiological conditions, eGFP fluorescence was retained in the vasculature and rarely detected in proximal tubule cells. Application of metronidazole induced podocyte injury and cell death as shown by TUNEL staining. Induction of podocyte injury resulted in a dramatic decrease of eGFP fluorescence in the vasculature over time (about 50% and 90% after 2 and 12 h respectively). Loss of vascular eGFP fluorescence was paralleled by an endocytosis-mediated accumulation of eGFP fluorescence in proximal tubule cells, indicating proteinuria. CONCLUSION We established a microscopy-based method to monitor the dynamics of glomerular barrier function during induction of podocyte injury in multiple zebrafish larvae simultaneously over 26 h.
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Affiliation(s)
- F. Siegerist
- Department of Anatomy and Cell Biology; University Medicine Greifswald; Greifswald Germany
| | - W. Zhou
- Department of Pediatrics and Communicable Diseases; University of Michigan; Ann Arbor MI USA
| | - K. Endlich
- Department of Anatomy and Cell Biology; University Medicine Greifswald; Greifswald Germany
| | - N. Endlich
- Department of Anatomy and Cell Biology; University Medicine Greifswald; Greifswald Germany
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23
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Abstract
Genetic studies of hereditary forms of nephrotic syndrome have identified several proteins that are involved in regulating the permselective properties of the glomerular filtration system. Further extensive research has elucidated the complex molecular basis of the glomerular filtration barrier and clearly established the pivotal role of podocytes in the pathophysiology of glomerular diseases. Podocyte architecture is centred on focal adhesions and slit diaphragms - multiprotein signalling hubs that regulate cell morphology and function. A highly interconnected actin cytoskeleton enables podocytes to adapt in order to accommodate environmental changes and maintain an intact glomerular filtration barrier. Actin-based endocytosis has now emerged as a regulator of podocyte integrity, providing an impetus for understanding the precise mechanisms that underlie the steady-state control of focal adhesion and slit diaphragm components. This Review outlines the role of actin dynamics and endocytosis in podocyte biology, and discusses how molecular heterogeneity in glomerular disorders could be exploited to deliver more rational therapeutic interventions, paving the way for targeted medicine in nephrology.
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24
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Gismondi A, Nanni V, Reina G, Orlanducci S, Terranova ML, Canini A. Nanodiamonds coupled with 5,7-dimethoxycoumarin, a plant bioactive metabolite, interfere with the mitotic process in B16F10 cells altering the actin organization. Int J Nanomedicine 2016; 11:557-74. [PMID: 26893562 PMCID: PMC4745844 DOI: 10.2147/ijn.s96614] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
For the first time, we coupled reduced detonation nanodiamonds (NDs) with a plant secondary metabolite, citropten (5,7-dimethoxycoumarin), and demonstrated how this complex was able to reduce B16F10 tumor cell growth more effectively than treatment with the pure molecule. These results encouraged us to find out the specific mechanism underlying this phenomenon. Internalization kinetics and quantification of citropten in cells after treatment with its pure or ND-conjugated form were measured, and it was revealed that the coupling between NDs and citropten was essential for the biological properties of the complex. We showed that the adduct was not able to induce apoptosis, senescence, or differentiation, but it determined cell cycle arrest, morphological changes, and alteration of mRNA levels of the cytoskeletal-related genes. The identification of metaphasic nuclei and irregular disposition of β-actin in the cell cytoplasm supported the hypothesis that citropten conjugated with NDs showed antimitotic properties in B16F10 cells. This work can be considered a pioneering piece of research that could promote and support the biomedical use of plant drug-functionalized NDs in cancer therapy.
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Affiliation(s)
- Angelo Gismondi
- Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Valentina Nanni
- Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Giacomo Reina
- Department of Chemical Science and Technology, University of Rome "Tor Vergata", Rome, Italy
| | - Silvia Orlanducci
- Department of Chemical Science and Technology, University of Rome "Tor Vergata", Rome, Italy
| | - Maria Letizia Terranova
- Department of Chemical Science and Technology, University of Rome "Tor Vergata", Rome, Italy
| | - Antonella Canini
- Department of Biology, University of Rome "Tor Vergata", Rome, Italy
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25
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Abstract
Podocytes are highly specialized cells of the kidney glomerulus that wrap around capillaries and that neighbor cells of the Bowman’s capsule. When it comes to glomerular filtration, podocytes play an active role in preventing plasma proteins from entering the urinary ultrafiltrate by providing a barrier comprising filtration slits between foot processes, which in aggregate represent a dynamic network of cellular extensions. Foot processes interdigitate with foot processes from adjacent podocytes and form a network of narrow and rather uniform gaps. The fenestrated endothelial cells retain blood cells but permit passage of small solutes and an overlying basement membrane less permeable to macromolecules, in particular to albumin. The cytoskeletal dynamics and structural plasticity of podocytes as well as the signaling between each of these distinct layers are essential for an efficient glomerular filtration and thus for proper renal function. The genetic or acquired impairment of podocytes may lead to foot process effacement (podocyte fusion or retraction), a morphological hallmark of proteinuric renal diseases. Here, we briefly discuss aspects of a contemporary view of podocytes in glomerular filtration, the patterns of structural changes in podocytes associated with common glomerular diseases, and the current state of basic and clinical research.
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Affiliation(s)
- Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
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26
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New LA, Martin CE, Scott RP, Platt MJ, Keyvani Chahi A, Stringer CD, Lu P, Samborska B, Eremina V, Takano T, Simpson JA, Quaggin SE, Jones N. Nephrin Tyrosine Phosphorylation Is Required to Stabilize and Restore Podocyte Foot Process Architecture. J Am Soc Nephrol 2016; 27:2422-35. [PMID: 26802179 DOI: 10.1681/asn.2015091048] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/17/2015] [Indexed: 11/03/2022] Open
Abstract
Podocytes are specialized epithelial cells of the kidney blood filtration barrier that contribute to permselectivity via a series of interdigitating actin-rich foot processes. Positioned between adjacent projections is a unique cell junction known as the slit diaphragm, which is physically connected to the actin cytoskeleton via the transmembrane protein nephrin. Evidence indicates that tyrosine phosphorylation of the intracellular tail of nephrin initiates signaling events, including recruitment of cytoplasmic adaptor proteins Nck1 and Nck2 that regulate actin cytoskeletal dynamics. Nephrin tyrosine phosphorylation is altered in human and experimental renal diseases characterized by pathologic foot process remodeling, prompting the hypothesis that phosphonephrin signaling directly influences podocyte morphology. To explore this possibility, we generated and analyzed knockin mice with mutations that disrupt nephrin tyrosine phosphorylation and Nck1/2 binding (nephrin(Y3F/Y3F) mice). Homozygous nephrin(Y3F/Y3F) mice developed progressive proteinuria accompanied by structural changes in the filtration barrier, including podocyte foot process effacement, irregular thickening of the glomerular basement membrane, and dilated capillary loops, with a similar but later onset phenotype in heterozygous animals. Furthermore, compared with wild-type mice, nephrin(Y3F/Y3F) mice displayed delayed recovery in podocyte injury models. Profiling of nephrin tyrosine phosphorylation dynamics in wild-type mice subjected to podocyte injury indicated site-specific differences in phosphorylation at baseline, injury, and recovery, which correlated with loss of nephrin-Nck1/2 association during foot process effacement. Our results define an essential requirement for nephrin tyrosine phosphorylation in stabilizing podocyte morphology and suggest a model in which dynamic changes in phosphotyrosine-based signaling confer plasticity to the podocyte actin cytoskeleton.
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Affiliation(s)
- Laura A New
- Departments of Molecular and Cellular Biology and
| | | | - Rizaldy P Scott
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Feinberg Cardiovascular Research Institute and Division of Nephrology and Hypertension, Northwestern University, Chicago, Illinois; and
| | - Mathew J Platt
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | | | | | - Peihua Lu
- Departments of Molecular and Cellular Biology and
| | | | - Vera Eremina
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Tomoko Takano
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Jeremy A Simpson
- Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Susan E Quaggin
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Feinberg Cardiovascular Research Institute and Division of Nephrology and Hypertension, Northwestern University, Chicago, Illinois; and
| | - Nina Jones
- Departments of Molecular and Cellular Biology and
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27
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Wang QZ, Gao HQ, Liang Y, Zhang J, Wang J, Qiu J. Cofilin1 is involved in hypertension-induced renal damage via the regulation of NF-κB in renal tubular epithelial cells. J Transl Med 2015; 13:323. [PMID: 26450610 PMCID: PMC4599745 DOI: 10.1186/s12967-015-0685-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 10/02/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Inflammation mediated by nuclear factor-κB (NF-κB) plays a critical role in the pathogenesis of hypertensive nephropathy (HN). Cytoskeletal remodelling is necessary for the activation of NF-κB. An actin-binding protein, cofilin-1 promotes dynamic alterations to the cytoskeleton by severing actin filaments. However, whether cofilin1 modulates NF-κB activity via cytoskeletal remodelling in the setting of hypertensive renal damage and what mechanisms underlie this phenomenon, remain unknown. METHODS Twenty-one-week old spontaneously hypertensive rats (SHRs) were treated with an antioxidant (100 or 250 mg kg(-1) day(-1)), grape seed proanthocyanidins extract (GSPE), for 22 weeks. Twenty-four-hour urinary protein, serum creatinine and urea nitrogen levels were measured. Haematoxylin and eosin (HE) staining was performed, and the expression levels of renal cortex cofilin1, monocyte chemotactic protein 1 (MCP1), interleukin-1β (IL1β) and NF-κB were evaluated via either Western blotting or immunohistochemistry. In vitro, human proximal renal tubular epithelial cells (HK-2 cells) were pre-incubated either with or without GSPE and subsequently treated with angiotensinII (AngII). Furthermore, a lentiviral shRNA-vector was utilized to knockdown cofilin1 expression in the HK-2 cells, which were stimulated with AngII. Actin filaments, NF-κB activity and several downstream inflammatory factors, including MCP1 and IL-1β, were investigated. RESULTS In addition to elevated blood pressure and 24 h urinary protein levels, NF-κB activity and the expression levels of MCP1 and IL-1β were significantly increased, resulting in tubulointerstitial inflammatory infiltration in SHRs. The phosphorylation (inactivation) of cofilin1 was increased in the kidneys of the SHRs. In vitro, AngII stimulation resulted in the phosphorylation of cofilin1, the formation of actin stress fibres and nuclear translocation of NF-κB p65 in the HK2 cells. Both GSPE pretreatment and the shRNA knockdown of cofilin1 inhibited Rel/p65 nuclear translocation, as well as the expression of both MCP-1 and IL-1β in the AngII-induced HK2 cells. CONCLUSION These results demonstrate that cofilin1 is involved in hypertensive nephropathy by modulating the nuclear translocation of NF-κB and the expression of its downstream inflammatory factors in renal tubular epithelial cells.
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Affiliation(s)
- Quan-Zhen Wang
- Department of Geriatric Cardiology, Qilu Hospital of Shandong University, 107 Wenhua Xi Rd, 250012, Jinan, People's Republic of China.
| | - Hai-Qing Gao
- Department of Geriatric Cardiology, Qilu Hospital of Shandong University, 107 Wenhua Xi Rd, 250012, Jinan, People's Republic of China.
| | - Ying Liang
- Department of Geriatric Cardiology, Qianfuoshan Hospital of Shandong Province, 16766 Jingshi Rd, 250000, Jinan, People's Republic of China.
| | - Jun Zhang
- Department of Geriatric Cardiology, Qilu Hospital of Shandong University, 107 Wenhua Xi Rd, 250012, Jinan, People's Republic of China.
| | - Jian Wang
- Department of Geriatric Cardiology, Qilu Hospital of Shandong University, 107 Wenhua Xi Rd, 250012, Jinan, People's Republic of China.
| | - Jie Qiu
- Department of Geriatric Cardiology, Qilu Hospital of Shandong University, 107 Wenhua Xi Rd, 250012, Jinan, People's Republic of China.
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Ahi EP, Steinhäuser SS, Pálsson A, Franzdóttir SR, Snorrason SS, Maier VH, Jónsson ZO. Differential expression of the aryl hydrocarbon receptor pathway associates with craniofacial polymorphism in sympatric Arctic charr. EvoDevo 2015; 6:27. [PMID: 26388986 PMCID: PMC4574265 DOI: 10.1186/s13227-015-0022-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 09/04/2015] [Indexed: 12/03/2022] Open
Abstract
Background The developmental basis of craniofacial morphology hinges on interactions of numerous signalling systems. Extensive craniofacial variation in the polymorphic Arctic charr, a member of the salmonid family, from Lake Thingvallavatn (Iceland), offers opportunities to find and study such signalling pathways and their key regulators, thereby shedding light on the developmental pathways, and the genetics of trophic divergence. Results To identify genes involved in the craniofacial differences between benthic and limnetic Arctic charr, we used transcriptome data from different morphs, spanning early development, together with data on craniofacial expression patterns and skeletogenesis in model vertebrate species. Out of 20 genes identified, 7 showed lower gene expression in benthic than in limnetic charr morphs. We had previously identified a conserved gene network involved in extracellular matrix (ECM) organization and skeletogenesis, showing higher expression in developing craniofacial elements of benthic than in limnetic Arctic charr morphs. The present study adds a second set of genes constituting an expanded gene network with strong, benthic–limnetic differential expression. To identify putative upstream regulators, we performed knowledge-based motif enrichment analyses on the regulatory sequences of the identified genes which yielded potential binding sites for a set of known transcription factors (TFs). Of the 8 TFs that we examined using qPCR, two (Ahr2b and Ap2) were found to be differentially expressed between benthic and limnetic charr. Expression analysis of several known AhR targets indicated higher activity of the AhR pathway during craniofacial development in benthic charr morphotypes. Conclusion These results suggest a key role of the aryl hydrocarbon receptor (AhR) pathway in the observed craniofacial differences between distinct charr morphotypes. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0022-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ehsan Pashay Ahi
- Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland
| | - Sophie S Steinhäuser
- Biomedical Center, University of Iceland, Vatnsmýrarvegur 16, 101 Reykjavik, Iceland
| | - Arnar Pálsson
- Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland ; Biomedical Center, University of Iceland, Vatnsmýrarvegur 16, 101 Reykjavik, Iceland
| | - Sigrídur Rut Franzdóttir
- Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland
| | - Sigurdur S Snorrason
- Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland
| | - Valerie H Maier
- Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland ; Biomedical Center, University of Iceland, Vatnsmýrarvegur 16, 101 Reykjavik, Iceland
| | - Zophonías O Jónsson
- Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik, Iceland ; Biomedical Center, University of Iceland, Vatnsmýrarvegur 16, 101 Reykjavik, Iceland
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29
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Abstract
The function of the kidney, filtering blood and concentrating metabolic waste into urine, takes place in an intricate and functionally elegant structure called the renal glomerulus. Normal glomerular function retains circulating cells and valuable macromolecular components of plasma in blood, resulting in urine with just trace amounts of proteins. Endothelial cells of glomerular capillaries, the podocytes wrapped around them, and the fused extracellular matrix these cells form altogether comprise the glomerular filtration barrier, a dynamic and highly selective filter that sieves on the basis of molecular size and electrical charge. Current understanding of the structural organization and the cellular and molecular basis of renal filtration draws from studies of human glomerular diseases and animal models of glomerular dysfunction.
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Affiliation(s)
- Rizaldy P Scott
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Susan E Quaggin
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
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30
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Hanke N, King BL, Vaske B, Haller H, Schiffer M. A Fluorescence-Based Assay for Proteinuria Screening in Larval Zebrafish (Danio rerio). Zebrafish 2015; 12:372-6. [PMID: 26125680 DOI: 10.1089/zeb.2015.1093] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Analysis of genes compromising the glomerular filtration barrier in rodent models using transgenic or knockdown approaches is time- and resource-consuming and often leads to unsatisfactory results. Therefore, it would be beneficial to have a selection tool indicating that your gene of interest is in fact associated with proteinuria. Zebrafish (Danio rerio) is a rapid screening tool to study effects in glomerular filtration barrier integrity after genetic manipulation. We use either injection of high-molecular-weight dextrans or a transgenic fluorescent fish line [Tg(l-fabp:DBP:EGFP)] expressing a vitamin D-binding protein fused with eGFP for indirect detection of proteinuria. A loss of high-molecular-weight proteins from the circulation of the fish into the urine can be identified by monitoring fluorescence intensity in the zebrafish eye. Paired with an optimized analysis method, this assay provides an effective screening solution to detect filtration barrier damage with proteinuria before moving to a mammalian system.
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Affiliation(s)
- Nils Hanke
- 1 Division of Nephrology, Hannover Medical School , Hannover, Germany
| | - Benjamin L King
- 2 Mount Desert Island Biological Laboratory , Bar Harbor, Maine
| | - Bernhard Vaske
- 3 Division of Biometry, Hannover Medical School , Hannover, Germany
| | - Hermann Haller
- 1 Division of Nephrology, Hannover Medical School , Hannover, Germany .,2 Mount Desert Island Biological Laboratory , Bar Harbor, Maine
| | - Mario Schiffer
- 1 Division of Nephrology, Hannover Medical School , Hannover, Germany .,2 Mount Desert Island Biological Laboratory , Bar Harbor, Maine
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31
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Pharmacological targeting of actin-dependent dynamin oligomerization ameliorates chronic kidney disease in diverse animal models. Nat Med 2015; 21:601-9. [PMID: 25962121 PMCID: PMC4458177 DOI: 10.1038/nm.3843] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/18/2015] [Indexed: 12/11/2022]
Abstract
Dysregulation of the actin cytoskeleton in podocytes represents a common pathway in the pathogenesis of proteinuria across a spectrum of chronic kidney diseases (CKD). The GTPase dynamin has been implicated in the maintenance of cellular architecture in podocytes through its direct interaction with actin. Furthermore, the propensity of dynamin to oligomerize into higher-order structures in an actin-dependent manner and to crosslink actin microfilaments into higher order structures have been correlated with increased actin polymerization and global organization of the actin cytoskeleton in the cell. We found that use of the small molecule Bis-T-23, which promotes actin-dependent dynamin oligomerization and thus increased actin polymerization in injured podocytes, was sufficient to improve renal health in diverse models of both transient kidney disease and of CKD. In particular, administration of Bis-T-23 in these renal disease models restored the normal ultrastructure of podocyte foot processes, lowered proteinuria, lowered collagen IV deposits in the mesangial matrix, diminished mesangial matrix expansion and extended lifespan. These results further establish that alterations in the actin cytoskeleton of kidney podocytes is a common hallmark of CKD, while also underscoring the significant regenerative potential of injured glomeruli and that targeting the oligomerization cycle of dynamin represents an attractive potential therapeutic target to treat CKD.
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32
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Grahammer F, Benzing T, Huber TB. New insights into mechanisms of glomerular injury and repair from the 10th International Podocyte Conference 2014. Kidney Int 2015; 87:885-93. [DOI: 10.1038/ki.2015.5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 11/11/2014] [Accepted: 11/20/2014] [Indexed: 01/17/2023]
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33
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Ohashi K. Roles of cofilin in development and its mechanisms of regulation. Dev Growth Differ 2015; 57:275-90. [DOI: 10.1111/dgd.12213] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 02/06/2023]
Affiliation(s)
- Kazumasa Ohashi
- Department of Biomolecular Sciences; Graduate School of Life Sciences; Tohoku University; Sendai Miyagi 980-8578 Japan
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34
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Genetic causes of proteinuria and nephrotic syndrome: impact on podocyte pathobiology. Pediatr Nephrol 2015; 30:221-33. [PMID: 24584664 PMCID: PMC4262721 DOI: 10.1007/s00467-014-2753-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/31/2013] [Accepted: 01/02/2014] [Indexed: 12/11/2022]
Abstract
In the past 20 years, multiple genetic mutations have been identified in patients with congenital nephrotic syndrome (CNS) and both familial and sporadic focal segmental glomerulosclerosis (FSGS). Characterization of the genetic basis of CNS and FSGS has led to the recognition of the importance of podocyte injury to the development of glomerulosclerosis. Genetic mutations induce injury due to effects on the podocyte's structure, actin cytoskeleton, calcium signaling, and lysosomal and mitochondrial function. Transgenic animal studies have contributed to our understanding of podocyte pathobiology. Podocyte endoplasmic reticulum stress response, cell polarity, and autophagy play a role in maintenance of podocyte health. Further investigations related to the effects of genetic mutations on podocytes may identify new pathways for targeting therapeutics for nephrotic syndrome.
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35
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Liu S, Wang W, Zhou X, Ding Z, Gu R. A 2-DE-based proteomic study on the toxicological effects of cisplatin in L02 cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 39:167-175. [PMID: 25528407 DOI: 10.1016/j.etap.2014.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/21/2014] [Accepted: 11/26/2014] [Indexed: 06/04/2023]
Abstract
Cisplatin is a chemotherapeutic agent for the treatment of various cancers. In this study, cisplatin-induced effects were characterized in vitro model of human liver cells (L02) using 2-DE-based proteomics. Results indicated that different cisplatin treatments primarily induced disturbances in protein synthesis and oxidative stress via differential mechanisms. Since the experimental concentrations of cisplatin described a hormesis effect in cell proliferation of L02 cells, it was expected to reveal the hormesis effects using proteomic markers. However, only confilin-1 was commonly up-regulated in three concentrations of cisplatin treatments showing a hormesis effects with a U-shape regulation. These results were highly consistent with many other toxico-proteomic studies, indicating that the toxico-proteomic responses based on dose-dependent protein responses were incongruent with the theoretically linear or hormetic concentration-effect relationship. Our findings suggested that a macroscopic hormesis phenomenon on the cell proliferation could not be reflected by proteomic responses induced by cisplatin treatments.
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Affiliation(s)
- Shu Liu
- The 2nd People's Hospital of Huaian, No. 62, Huaihainan Road, Huaian 223002, PR China
| | - Wei Wang
- The 2nd People's Hospital of Huaian, No. 62, Huaihainan Road, Huaian 223002, PR China.
| | - Xueyi Zhou
- The 2nd People's Hospital of Huaian, No. 62, Huaihainan Road, Huaian 223002, PR China
| | - Zongli Ding
- The 2nd People's Hospital of Huaian, No. 62, Huaihainan Road, Huaian 223002, PR China
| | - Runhuan Gu
- The 2nd People's Hospital of Huaian, No. 62, Huaihainan Road, Huaian 223002, PR China
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36
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Du HQ, Chen L, Wang Y, Wang LJ, Yan H, Liu HY, Xiao H. Increasing radiosensitivity with the downregulation of cofilin-1 in U251 human glioma cells. Mol Med Rep 2014; 11:3354-60. [PMID: 25529407 PMCID: PMC4368146 DOI: 10.3892/mmr.2014.3125] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 11/19/2014] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to examine the association between cofilin-1 (CFL1) and radioresistance in human glioma U251 cells. CFL1 expression was downregulated and upregulated in U251 cells through the transfection of CFL1-small interfering (si)RNA and pcDNA3.1-CFL1, respectively. The radiosensitivity of U251 cells and established radioresistant U251 cells (RR-U251) was evaluated using cell viability, migration and invasion ability assays. Cell cycle distribution was also examined. The results showed that CFL1 expression was significantly increased in RR-U251 cells; in addition, the cell viability, migration and invasion ability of RR-U251 cells were significantly enhanced compared to those of the normal U251 cells, whereas the number of cells arrested in G2 phase was markedly decreased. In CFL1-silenced RR-U251 and CFL1-silenced U251 cells, the cell viability, migration and invasion abilities were significantly downregulated and the number of cells arrested in G2 phase was increased compared to that of the untransfected cells. In U251 cells overexpressing CFL1, cell viability, migration and invasion abilities were markedly upregulated and the number of cells arrested in G2 phase was decreased. In conclusion, the results of the present study suggested that downregulation of CFL1 may increase radiosensitivity in U251 cells.
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Affiliation(s)
- Hua-Qing Du
- Neuro‑Psychiatric Institute, Nanjing Medical University, Affiliated Nanjing Brain Hospital, Nanjing, Jiangsu 210029, P.R. China
| | - Ling Chen
- Neuro‑Psychiatric Institute, Nanjing Medical University, Affiliated Nanjing Brain Hospital, Nanjing, Jiangsu 210029, P.R. China
| | - Ying Wang
- Neuro‑Psychiatric Institute, Nanjing Medical University, Affiliated Nanjing Brain Hospital, Nanjing, Jiangsu 210029, P.R. China
| | - Li-Jun Wang
- Neuro‑Psychiatric Institute, Nanjing Medical University, Affiliated Nanjing Brain Hospital, Nanjing, Jiangsu 210029, P.R. China
| | - Hua Yan
- Department of Neurosurgery, Nanjing Medical University, Affiliated Nanjing Brain Hospital, Nanjing, Jiangsu 210029, P.R. China
| | - Hong-Yi Liu
- Department of Neurosurgery, Nanjing Medical University, Affiliated Nanjing Brain Hospital, Nanjing, Jiangsu 210029, P.R. China
| | - Hong Xiao
- Neuro‑Psychiatric Institute, Nanjing Medical University, Affiliated Nanjing Brain Hospital, Nanjing, Jiangsu 210029, P.R. China
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Kroeger PT, Wingert RA. Using zebrafish to study podocyte genesis during kidney development and regeneration. Genesis 2014; 52:771-92. [PMID: 24920186 DOI: 10.1002/dvg.22798] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 06/08/2014] [Accepted: 06/09/2014] [Indexed: 12/21/2022]
Abstract
During development, vertebrates form a progression of up to three different kidneys that are comprised of functional units termed nephrons. Nephron composition is highly conserved across species, and an increasing appreciation of the similarities between zebrafish and mammalian nephron cell types has positioned the zebrafish as a relevant genetic system for nephrogenesis studies. A key component of the nephron blood filter is a specialized epithelial cell known as the podocyte. Podocyte research is of the utmost importance as a vast majority of renal diseases initiate with the dysfunction or loss of podocytes, resulting in a condition known as proteinuria that causes nephron degeneration and eventually leads to kidney failure. Understanding how podocytes develop during organogenesis may elucidate new ways to promote nephron health by stimulating podocyte replacement in kidney disease patients. In this review, we discuss how the zebrafish model can be used to study kidney development, and how zebrafish research has provided new insights into podocyte lineage specification and differentiation. Further, we discuss the recent discovery of podocyte regeneration in adult zebrafish, and explore how continued basic research using zebrafish can provide important knowledge about podocyte genesis in embryonic and adult environments. genesis 52:771-792, 2014. © 2014 Wiley Periodicals, Inc.
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Affiliation(s)
- Paul T Kroeger
- Department of Biological Sciences and Center for Zebrafish Research, University of Notre Dame, Notre Dame, Indiana, 46556
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Wasik AA, Koskelainen S, Hyvönen ME, Musante L, Lehtonen E, Koskenniemi K, Tienari J, Vaheri A, Kerjaschki D, Szalay C, Révész C, Varmanen P, Nyman TA, Hamar P, Holthöfer H, Lehtonen S. Ezrin Is Down-Regulated in Diabetic Kidney Glomeruli and Regulates Actin Reorganization and Glucose Uptake via GLUT1 in Cultured Podocytes. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1727-39. [DOI: 10.1016/j.ajpath.2014.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 02/28/2014] [Accepted: 03/05/2014] [Indexed: 01/27/2023]
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Stødkilde L, Palmfeldt J, Nilsson L, Carlsen I, Wang Y, Nørregaard R, Frøkiaer J. Proteomic identification of early changes in the renal cytoskeleton in obstructive uropathy. Am J Physiol Renal Physiol 2014; 306:F1429-41. [PMID: 24761003 DOI: 10.1152/ajprenal.00244.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Bilateral ureteral obstruction (BUO) is associated with renal damage and impaired ability to concentrate urine and is known to induce alterations in an array of kidney proteins. The aim of this study was to identify acute proteomic alterations induced by BUO. Rats were subjected to BUO for 2, 6, or 24 h. Mass spectrometry-based proteomics was performed on the renal inner medulla, and protein changes in the obstructed group were identified. Significant changes were successfully identified for 109 proteins belonging to different biological classes. Interestingly, proteins belonging to the cytoskeleton and proteins related to cytoskeletal regulation were found to be biologically enriched in BUO using online-accessible tools. Western blots confirmed the selected results, demonstrating acute downregulation of proteins belonging to all three cytoskeletal components. The microfilament protein β-actin and the intermediate filament proteins pankeratin and vimentin were all downregulated. β-Tubulin, an important microtubular protein, was found to be significantly downregulated after 24 h. Also, there was significant upregulation of cofilin, an actin-binding protein known to be upregulated in other nephropathy models. Furthermore, both upregulation and downregulation of cytoskeletal motor and regulatory proteins were observed. These findings were confirmed by immunohistochemistry, which clearly showed alterations in labeling in the inner medulla. Interestingly, we were able to confirm selected results in mpkCCD cells exposed to mechanical stretch. Our findings add to the knowledge of BUO-induced acute changes in the renal cytoskeleton and suggest that these molecular changes are partly mediated by increased stretch of the cells during obstruction.
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Affiliation(s)
- Lene Stødkilde
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Johan Palmfeldt
- Research Unit for Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark; and Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Line Nilsson
- Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Inge Carlsen
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Yan Wang
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Rikke Nørregaard
- Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
| | - Jørgen Frøkiaer
- Department of Clinical Physiology and Molecular Imaging, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine Aarhus University Hospital, Aarhus, Denmark
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Li X, Zhang X, Li X, Wang X, Wang S, Ding J. Cyclosporine A protects podocytes via stabilization of cofilin-1 expression in the unphosphorylated state. Exp Biol Med (Maywood) 2014; 239:922-936. [PMID: 24737737 DOI: 10.1177/1535370214530365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Podocyte foot process (FP) is dysregulated in nephrotic syndrome. The effacement of podocyte FPs typically arises following perturbations in the actin cytoskeleton. Recent data suggest that the effects of calcineurin (CaN) inhibitor cyclosporine A (CsA) are independent of its effects on T-cells, and CsA has been identified as stabilizing the actin cytoskeleton through stabilizing synaptopodin in podocytes, and thereby directly reducing proteinuria. Other studies showed that CsA could regulate cofilin-1 directly within tubular epithelial cells. However, whether synaptopodin is the only target of CsA or whether the antiproteinuric role of CsA is played by regulating cofilin-1 in podocytes has not been studied. In the present study, changes in the expression and distribution of nephrin, synaptopodin, cofilin-1 and phosphorylated cofilin-1 (pho-cofilin-1) were detected in both puromycin aminonucleoside (PAN) induced nephrotic rats treated with CsA and cultured podocytes exposed to PAN with/without CsA. Cofilin-1, synaptopodin mRNA was knocked down or combined by siRNA to investigate whether cofilin-1 was critical for the protective effect of CsA and whether the effect of CsA on cofilin-1 was independent of its effect on synaptopodin. We found that CsA reduced proteinuria and repaired FP effacement of PAN-induced nephropathy, restored expression of nephrin, synaptopodin, cofilin-1, pho-cofilin-1 both in vivo and in vitro. CsA also repaired actin cytoskeleton impaired by PAN in vitro. The protective effect of CsA was diminished when cofilin-1 was knocked down compared to negative control. Synaptopodin knocked down had no effect on cofilin-1. The protective effect of CsA decreased significantly when cofilin-1 and synaptopodin were simultaneously knocked down compared to only cofilin-1 knock down. In conclusion, the antiproteinuric effect of CsA is derived from the stabilization of the podocyte actin cytoskeleton by upregulating expression of cofilin-1, which was independent of its effect on synaptopodin.
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Affiliation(s)
- Xiaoyan Li
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Xiaoyan Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Xuejuan Li
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Xuejing Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Suxia Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
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Gbadegesin RA, Hall G, Adeyemo A, Hanke N, Tossidou I, Burchette J, Wu G, Homstad A, Sparks MA, Gomez J, Jiang R, Alonso A, Lavin P, Conlon P, Korstanje R, Stander MC, Shamsan G, Barua M, Spurney R, Singhal PC, Kopp JB, Haller H, Howell D, Pollak MR, Shaw AS, Schiffer M, Winn MP. Mutations in the gene that encodes the F-actin binding protein anillin cause FSGS. J Am Soc Nephrol 2014; 25:1991-2002. [PMID: 24676636 DOI: 10.1681/asn.2013090976] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
FSGS is characterized by segmental scarring of the glomerulus and is a leading cause of kidney failure. Identification of genes causing FSGS has improved our understanding of disease mechanisms and points to defects in the glomerular epithelial cell, the podocyte, as a major factor in disease pathogenesis. Using a combination of genome-wide linkage studies and whole-exome sequencing in a kindred with familial FSGS, we identified a missense mutation R431C in anillin (ANLN), an F-actin binding cell cycle gene, as a cause of FSGS. We screened 250 additional families with FSGS and found another variant, G618C, that segregates with disease in a second family with FSGS. We demonstrate upregulation of anillin in podocytes in kidney biopsy specimens from individuals with FSGS and kidney samples from a murine model of HIV-1-associated nephropathy. Overexpression of R431C mutant ANLN in immortalized human podocytes results in enhanced podocyte motility. The mutant anillin displays reduced binding to the slit diaphragm-associated scaffold protein CD2AP. Knockdown of the ANLN gene in zebrafish morphants caused a loss of glomerular filtration barrier integrity, podocyte foot process effacement, and an edematous phenotype. Collectively, these findings suggest that anillin is important in maintaining the integrity of the podocyte actin cytoskeleton.
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Affiliation(s)
- Rasheed A Gbadegesin
- Departments of Pediatrics, Center for Human Genetics, Duke University Medical Center, Durham, North Carolina;
| | - Gentzon Hall
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina; Medicine, and
| | - Adebowale Adeyemo
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Nils Hanke
- Department of Nephrology, Hannover Medical School, Hannover, Germany; Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Irini Tossidou
- Department of Nephrology, Hannover Medical School, Hannover, Germany
| | | | - Guanghong Wu
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina; Medicine, and
| | - Alison Homstad
- Departments of Pediatrics, Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | | | | | - Ruiji Jiang
- Departments of Pediatrics, Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Andrea Alonso
- Departments of Pediatrics, Center for Human Genetics, Duke University Medical Center, Durham, North Carolina
| | - Peter Lavin
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina; Medicine, and Trinity Health Kidney Centre, Tallaght Hospital, Trinity College, Dublin, Ireland
| | - Peter Conlon
- Department of Nephrology, Beaumont Hospital, Dublin, Ireland
| | - Ron Korstanje
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine; The Jackson Laboratory, Bar Harbor, Maine
| | - M Christine Stander
- Howard Hughes Medical Institute, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Ghaidan Shamsan
- Howard Hughes Medical Institute, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Moumita Barua
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | | | - Pravin C Singhal
- Feinstein Institute for Medical Research, North Shore-LIJ Health System, Manhasset, New York; and
| | - Jeffrey B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Hermann Haller
- Department of Nephrology, Hannover Medical School, Hannover, Germany; Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | | | - Martin R Pollak
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Andrey S Shaw
- Howard Hughes Medical Institute, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Mario Schiffer
- Department of Nephrology, Hannover Medical School, Hannover, Germany; Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Michelle P Winn
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina; Medicine, and
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Miceli R, Kroeger P, Wingert R. Molecular Mechanisms of Podocyte Development Revealed by Zebrafish Kidney Research. ACTA ACUST UNITED AC 2014; 3. [PMID: 25485314 PMCID: PMC4254692 DOI: 10.4172/2168-9296.1000138] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Elucidating the gene regulatory networks that control kidney development can provide information about the origins of renal birth defects and kidney disease, as well as insights relevant to the design of clinical interventions for these conditions. The kidney is composed of functional units termed nephrons. Renal malfunction often arises from damage to cells known as podocytes, which are highly specialized epithelial cells that comprise the blood filter, or glomerulus, located on each nephron. Podocytes interact with the vasculature to create an elaborate sieve that collects circulatory fluid, and this filtrate enters the nephron where it is modified to produce urine and balance water homeostasis. Podocytes are an essential cellular component of the glomerular filtration barrier, helping to protect nephrons from the entry of large proteins and circulatory cells. Podocyte loss has catastrophic consequences for renal function and overall health, as podocyte destruction leads to nephron damage and pathological conditions like chronic kidney disease. Despite their importance, there is still a rather limited understanding about the molecular pathways that control podocyte formation. In recent years, however, studies of podocyte development using the zebrafish embryonic kidney, or pronephros, have been an expanding area of nephrology research. Zebrafish form an anatomically simple pronephros comprised of two nephrons that share a single blood filter, and podocyte progenitors can be easily visualized throughout the process of glomerular development. The zebrafish is an especially useful system for studying the mechanisms that are essential for formation of nephron cell types like podocytes due to the high genetic conservation between vertebrate species, including humans. In this review, we discuss how research using the zebrafish has provided new insights into the molecular regulation of the podocyte lineage during kidney ontogeny, complementing contemporary research in other animal models.
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Affiliation(s)
- R Miceli
- Department of Biological Sciences and Center for Zebrafish Research, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Pt Kroeger
- Department of Biological Sciences, University of Notre, Dame, 100 Galvin Life Sciences, Notre Dame, USA
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Endlich N, Simon O, Göpferich A, Wegner H, Moeller MJ, Rumpel E, Kotb AM, Endlich K. Two-photon microscopy reveals stationary podocytes in living zebrafish larvae. J Am Soc Nephrol 2013; 25:681-6. [PMID: 24309184 DOI: 10.1681/asn.2013020178] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Podocytes are an essential component of the glomerular filtration barrier and cover the outer aspect of glomerular capillaries. They form a complex actin-based cytoskeleton in vivo and show prominent motility in vitro, but whether podocytes are stationary or mobile in vivo is debated. To address this question, the pronephros of translucent zebrafish larvae (casper) expressing enhanced green fluorescent protein (eGFP) specifically in podocytes (wt1a:eGFP larvae) was observed by intravital two-photon microscopy over extended periods of time. Podocyte cell bodies and the interdigitating branching pattern of major processes could be resolved with a resolution of approximately 1 µm in the xy-plane. Time-lapse imaging of zebrafish larvae at 5-7 days after fertilization demonstrated that podocytes neither migrated nor changed the branching pattern of their major processes over a time period of up to 23 hours. In summary, we show by extended intravital two-photon microscopy that podocytes are stationary cells in the intact glomerulus of a translucent zebrafish with fluorescently-labeled podocytes.
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Affiliation(s)
- Nicole Endlich
- Department of Anatomy and Cell Biology, Universitätsmedizin Greifswald, Greifswald, Germany
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"Zebrafishing" for novel genes relevant to the glomerular filtration barrier. BIOMED RESEARCH INTERNATIONAL 2013; 2013:658270. [PMID: 24106712 PMCID: PMC3784067 DOI: 10.1155/2013/658270] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 07/15/2013] [Indexed: 01/09/2023]
Abstract
Data for genes relevant to glomerular filtration barrier function or proteinuria is continually increasing in an era of microarrays, genome-wide association studies, and quantitative trait locus analysis. Researchers are limited by published literature searches to select the most relevant genes to investigate. High-throughput cell cultures and other in vitro systems ultimately need to demonstrate proof in an in vivo model. Generating mammalian models for the genes of interest is costly and time intensive, and yields only a small number of test subjects. These models also have many pitfalls such as possible embryonic mortality and failure to generate phenotypes or generate nonkidney specific phenotypes. Here we describe an in vivo zebrafish model as a simple vertebrate screening system to identify genes relevant to glomerular filtration barrier function. Using our technology, we are able to screen entirely novel genes in 4–6 weeks in hundreds of live test subjects at a fraction of the cost of a mammalian model. Our system produces consistent and reliable evidence for gene relevance in glomerular kidney disease; the results then provide merit for further analysis in mammalian models.
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Abstract
Observations of hereditary glomerular disease support the contention that podocyte intercellular junction proteins are essential for junction formation and maintenance. Genetic deletion of most of these podocyte intercellular junction proteins results in foot process effacement and proteinuria. This review focuses on the current understanding of molecular mechanisms by which podocyte intercellular junction proteins such as the nephrin-neph1-podocin-receptor complex coordinate cytoskeletal dynamics and thus intercellular junction formation, maintenance, and injury-dependent remodeling.
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New LA, Keyvani Chahi A, Jones N. Direct regulation of nephrin tyrosine phosphorylation by Nck adaptor proteins. J Biol Chem 2012. [PMID: 23188823 DOI: 10.1074/jbc.m112.439463] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transmembrane protein nephrin is a key component of the kidney slit diaphragm that contributes to the morphology of podocyte foot processes through signaling to the underlying actin cytoskeleton. We have recently reported that tyrosine phosphorylation of the cytoplasmic tail of nephrin facilitates recruitment of Nck SH2/SH3 adaptor proteins and subsequent actin remodeling and that phosphorylation of the Nck binding sites on nephrin is decreased during podocyte injury. We now demonstrate that Nck directly modulates nephrin phosphorylation through formation of a signaling complex with the Src family kinase Fyn. The ability of Nck to enhance nephrin phosphorylation is compromised in the presence of a Src family kinase inhibitor and when the SH3 domains of Nck are mutated. Furthermore, induced loss of Nck expression in podocytes in vivo is associated with a rapid reduction in nephrin tyrosine phosphorylation. Our results suggest that Nck may facilitate dynamic signaling events at the slit diaphragm by promoting Fyn-dependent phosphorylation of nephrin, which may be important in the regulation of foot process morphology and response to podocyte injury.
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Affiliation(s)
- Laura A New
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Gerlach GF, Wingert RA. Kidney organogenesis in the zebrafish: insights into vertebrate nephrogenesis and regeneration. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 2:559-85. [PMID: 24014448 DOI: 10.1002/wdev.92] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Vertebrates form a progressive series of up to three kidney organs during development-the pronephros, mesonephros, and metanephros. Each kidney derives from the intermediate mesoderm and is comprised of conserved excretory units called nephrons. The zebrafish is a powerful model for vertebrate developmental genetics, and recent studies have illustrated that zebrafish and mammals share numerous similarities in nephron composition and physiology. The zebrafish embryo forms an architecturally simple pronephros that has two nephrons, and these eventually become a scaffold onto which a mesonephros of several hundred nephrons is constructed during larval stages. In adult zebrafish, the mesonephros exhibits ongoing nephrogenesis, generating new nephrons from a local pool of renal progenitors during periods of growth or following kidney injury. The characteristics of the zebrafish pronephros and mesonephros make them genetically tractable kidney systems in which to study the functions of renal genes and address outstanding questions about the mechanisms of nephrogenesis. Here, we provide an overview of the formation and composition of these zebrafish kidney organs, and discuss how various zebrafish mutants, gene knockdowns, and transgenic models have created frameworks in which to further delineate nephrogenesis pathways.
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Affiliation(s)
- Gary F Gerlach
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
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Chase SE, Encina CV, Stolzenburg LR, Tatum AH, Holzman LB, Krendel M. Podocyte-specific knockout of myosin 1e disrupts glomerular filtration. Am J Physiol Renal Physiol 2012; 303:F1099-106. [PMID: 22811491 DOI: 10.1152/ajprenal.00251.2012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Myosin 1e (myo1e) is an actin-dependent molecular motor that plays an important role in kidney functions. Complete knockout of myo1e in mice and Myo1E mutations in humans are associated with nephrotic syndrome and focal segmental glomerulosclerosis. In this paper, we tested the hypothesis that myo1e is necessary for normal functions of glomerular visceral epithelial cells (podocytes) using podocyte-targeted knockout of myo1e. Myo1e was selectively knocked out in podocytes using Cre-mediated recombination controlled by the podocin promoter. Myo1e loss from podocytes resulted in proteinuria, podocyte foot process effacement, and glomerular basement membrane disorganization. Our findings indicate that myo1e expression in podocytes is necessary for normal glomerular filtration and that podocyte defects are likely to represent the primary pathway leading to glomerular disease associated with Myo1E mutations.
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Affiliation(s)
- Sharon E Chase
- Dept. of Cell and Developmental Biology, SUNY Upstate Medical Univ., 750 E. Adams St., Syracuse, NY 13210, USA
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