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Veloso Pereira BM, Zeng Y, Maggiore JC, Schweickart RA, Eng DG, Kaverina N, McKinzie SR, Chang A, Loretz CJ, Thieme K, Hukriede NA, Pippin JW, Wessely O, Shankland SJ. Podocyte injury at young age causes premature senescence and worsens glomerular aging. Am J Physiol Renal Physiol 2024; 326:F120-F134. [PMID: 37855038 PMCID: PMC11198990 DOI: 10.1152/ajprenal.00261.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/10/2023] [Accepted: 10/10/2023] [Indexed: 10/20/2023] Open
Abstract
As life expectancy continues to rise, age-related diseases are becoming more prevalent. For example, proteinuric glomerular diseases typified by podocyte injury have worse outcomes in the elderly compared with young patients. However, the reasons are not well understood. We hypothesized that injury to nonaged podocytes induces senescence, which in turn augments their aging processes. In primary cultured human podocytes, injury induced by a cytopathic antipodocyte antibody, adriamycin, or puromycin aminonucleoside increased the senescence-related genes CDKN2A (p16INK4a/p14ARF), CDKN2D (p19INK4d), and CDKN1A (p21). Podocyte injury in human kidney organoids was accompanied by increased expression of CDKN2A, CDKN2D, and CDKN1A. In young mice, experimental focal segmental glomerulosclerosis (FSGS) induced by adriamycin and antipodocyte antibody increased the glomerular expression of p16, p21, and senescence-associated β-galactosidase (SA-β-gal). To assess the long-term effects of early podocyte injury-induced senescence, we temporally followed young mice with experimental FSGS through adulthood (12 m of age) and middle age (18 m of age). p16 and Sudan black staining were higher at middle age in mice with earlier FSGS compared with age-matched mice that did not get FSGS when young. This was accompanied by lower podocyte density, reduced canonical podocyte protein expression, and increased glomerular scarring. These results are consistent with injury-induced senescence in young podocytes, leading to increased senescence of podocytes by middle age accompanied by lower podocyte lifespan and health span.NEW & NOTEWORTHY Glomerular function is decreased by aging. However, little is known about the molecular mechanisms involved in age-related glomerular changes and which factors could contribute to a worse glomerular aging process. Here, we reported that podocyte injury in young mice and culture podocytes induced senescence, a marker of aging, and accelerates glomerular aging when compared with healthy aging mice.
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Affiliation(s)
- Beatriz Maria Veloso Pereira
- Division of Nephrology, University of Washington, Seattle, Washington, United States
- Department of Physiology and Biophysics, University of São Paulo, São Paulo, Brazil
| | - Yuting Zeng
- Department of Chemistry, University of Washington, Seattle, Washington, United States
| | - Joseph C Maggiore
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | | | - Diana G Eng
- Division of Nephrology, University of Washington, Seattle, Washington, United States
| | - Natalya Kaverina
- Division of Nephrology, University of Washington, Seattle, Washington, United States
| | - Sierra R McKinzie
- Division of Nephrology, University of Washington, Seattle, Washington, United States
| | - Anthony Chang
- Department of Pathology, University of Chicago, Chicago, Illinois, United States
| | - Carol J Loretz
- Division of Nephrology, University of Washington, Seattle, Washington, United States
| | - Karina Thieme
- Department of Physiology and Biophysics, University of São Paulo, São Paulo, Brazil
| | - Neil A Hukriede
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Jeffrey W Pippin
- Division of Nephrology, University of Washington, Seattle, Washington, United States
| | - Oliver Wessely
- Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States
| | - Stuart J Shankland
- Division of Nephrology, University of Washington, Seattle, Washington, United States
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, United States
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Bharati J, Chander PN, Singhal PC. Parietal Epithelial Cell Behavior and Its Modulation by microRNA-193a. Biomolecules 2023; 13:biom13020266. [PMID: 36830635 PMCID: PMC9953542 DOI: 10.3390/biom13020266] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 02/04/2023] Open
Abstract
Glomerular parietal epithelial cells (PECs) have been increasingly recognized to have crucial functions. Lineage tracking in animal models showed the expression of a podocyte phenotype by PECs during normal glomerular growth and after acute podocyte injury, suggesting a reparative role of PECs. Conversely, activated PECs are speculated to be pathogenic and comprise extracapillary proliferation in focal segmental glomerulosclerosis (FSGS) and crescentic glomerulonephritis (CrescGN). The reparative and pathogenic roles of PECs seem to represent two sides of PEC behavior directed by the local milieu and mediators. Recent studies suggest microRNA-193a (miR193a) is involved in the pathogenesis of FSGS and CrescGN. In a mouse model of primary FSGS, the induction of miR193a caused the downregulation of Wilms' tumor protein, leading to the dedifferentiation of podocytes. On the other hand, the inhibition of miR193a resulted in reduced crescent lesions in a mouse model of CrescGN. Interestingly, in vitro studies report that the downregulation of miR193a induces trans-differentiation of PECs into a podocyte phenotype. This narrative review highlights the critical role of PEC behavior in health and during disease and its modulation by miR193a.
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Affiliation(s)
- Joyita Bharati
- Institute of Molecular Medicine, Feinstein Institute for Medical Research and Department of Medicine, Zucker School of Medicine at Hofstra-Northwell, Hempstead, NY 11549, USA
- Department of Nephrology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Praveen N. Chander
- New York Medical College, Touro College and University System Valhalla, Valhalla, NY 10595, USA
| | - Pravin C. Singhal
- Institute of Molecular Medicine, Feinstein Institute for Medical Research and Department of Medicine, Zucker School of Medicine at Hofstra-Northwell, Hempstead, NY 11549, USA
- Correspondence:
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Huang Y, Zhao X, Zhang Q, Yang X, Hou G, Peng C, Jia M, Zhou L, Yamamoto T, Zheng J. Novel therapeutic perspectives for crescentic glomerulonephritis through targeting parietal epithelial cell activation and proliferation. Expert Opin Ther Targets 2023; 27:55-69. [PMID: 36738160 DOI: 10.1080/14728222.2023.2177534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Kidney injury is clinically classified as crescentic glomerulonephritis (CrGN) when ≥50% of the glomeruli in a biopsy sample contain crescentic lesions. However, current strategies, such as systemic immunosuppressive therapy and plasmapheresis for CrGN, are partially effective, and these drugs have considerable systemic side effects. Hence, targeted therapy to prevent glomerular crescent formation and expansion remains an unmet clinical need. AREAS COVERED Hyperproliferative parietal epithelial cells (PECs) are the main constituent cells of the glomerular crescent with cell-tracing evidence. Crescents obstruct the flow of primary urine, pressure the capillaries, and degenerate the affected nephrons. We reviewed the markers of PEC activation and proliferation, potential therapeutic effects of thrombin and thrombin receptor inhibitors, and how podocytes cross-talk with PECs. These experiments may help identify potential early specific targets for the prevention and treatment of glomerular crescentic injury. EXPERT OPINION Inhibiting PEC activation and proliferation in CrGN can alleviate glomerular crescent progression, which has been supported by preclinical studies with evidence of genetic deletion. Clarifying the outcome of PEC transformation to the podocyte phenotype and suppressing thrombin, thrombin receptors, and PEC hyperproliferation in early therapeutic strategies will be the research goals in the next ten years.
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Affiliation(s)
- Yanjie Huang
- School of Pediatric Medicine, Henan University of Chinese Medicine, Zhengzhou, Henan, China.,Department of Pediatrics, the First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Xueru Zhao
- School of Pediatric Medicine, Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Qiushuang Zhang
- Department of Pediatrics, the First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Xiaoqing Yang
- Department of Pediatrics, the First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Gailing Hou
- School of Pediatric Medicine, Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Chaoqun Peng
- School of Pediatric Medicine, Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Mengzhen Jia
- School of Pediatric Medicine, Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Li Zhou
- School of Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Tatsuo Yamamoto
- Department of Nephrology, Fujieda Municipal General Hospital, 4-1-11 Surugadai, Fujieda, Japan
| | - Jian Zheng
- Institute of Pediatrics of Traditional Chinese Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian, China
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Differences in Immunohistochemical and Ultrastructural Features between Podocytes and Parietal Epithelial Cells (PECs) Are Observed in Developing, Healthy Postnatal, and Pathologically Changed Human Kidneys. Int J Mol Sci 2022; 23:ijms23147501. [PMID: 35886848 PMCID: PMC9322852 DOI: 10.3390/ijms23147501] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/30/2022] [Accepted: 07/05/2022] [Indexed: 02/06/2023] Open
Abstract
During human kidney development, cells of the proximal nephron gradually differentiate into podocytes and parietal epithelial cells (PECs). Podocytes are terminally differentiated cells that play a key role in both normal and pathological kidney function. Therefore, the potential of podocytes to regenerate or be replaced by other cell populations (PECs) is of great interest for the possible treatment of kidney diseases. In the present study, we analyzed the proliferation and differentiation capabilities of podocytes and PECs, changes in the expression pattern of nestin, and several early proteins including WNT4, Notch2, and Snail, as well as Ki-67, in tissues of developing, postnatal, and pathologically changed human kidneys by using immunohistochemistry and electron microscopy. Developing PECs showed a higher proliferation rate than podocytes, whereas nestin expression characterized only podocytes and pathologically changed kidneys. In the developing kidneys, WNT4 and Notch2 expression increased moderately in podocytes and strongly in PECs, whereas Snail increased only in PECs in the later fetal period. During human kidney development, WNT4, Notch2, and Snail are involved in early nephrogenesis control. In kidneys affected by congenital nephrotic syndrome of the Finnish type (CNF) and focal segmental glomerulosclerosis (FSGS), WNT4 decreased in both cell populations, whereas Notch2 decreased in FSGS. In contrast, Snail increased both in CNF and FSGS, whereas Notch2 increased only in CNF. Electron microscopy revealed cytoplasmic processes spanning the urinary space between the podocytes and PECs in developing and healthy postnatal kidneys, whereas the CNF and FSGS kidneys were characterized by numerous cellular bridges containing cells with strong expression of nestin and all analyzed proteins. Our results indicate that the mechanisms of gene control in nephrogenesis are reactivated under pathological conditions. These mechanisms could have a role in restoring glomerular integrity by potentially inducing the regeneration of podocytes from PECs.
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Li ZH, Guo XY, Quan XY, Yang C, Liu ZJ, Su HY, An N, Liu HF. The Role of Parietal Epithelial Cells in the Pathogenesis of Podocytopathy. Front Physiol 2022; 13:832772. [PMID: 35360248 PMCID: PMC8963495 DOI: 10.3389/fphys.2022.832772] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/07/2022] [Indexed: 02/05/2023] Open
Abstract
Podocytopathy is the most common feature of glomerular disorder characterized by podocyte injury- or dysfunction-induced excessive proteinuria, which ultimately develops into glomerulosclerosis and results in persistent loss of renal function. Due to the lack of self-renewal ability of podocytes, mild podocyte depletion triggers replacement and repair processes mostly driven by stem cells or resident parietal epithelial cells (PECs). In contrast, when podocyte recovery fails, activated PECs contribute to the establishment of glomerular lesions. Increasing evidence suggests that PECs, more than just bystanders, have a crucial role in various podocytopathies, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, diabetic nephropathy, IgA nephropathy, and lupus podocytopathy. In this review, we attempt to dissect the diverse role of PECs in the pathogenesis of podocytopathy based on currently available information.
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Latt KZ, Heymann J, Jessee JH, Rosenberg AZ, Berthier CC, Arazi A, Eddy S, Yoshida T, Zhao Y, Chen V, Nelson GW, Cam M, Kumar P, Mehta M, Kelly MC, Kretzler M, Ray PE, Moxey-Mims M, Gorman GH, Lechner BL, Regunathan-Shenk R, Raj DS, Susztak K, Winkler CA, Kopp JB. Urine Single-Cell RNA Sequencing in Focal Segmental Glomerulosclerosis Reveals Inflammatory Signatures. Kidney Int Rep 2022; 7:289-304. [PMID: 35155868 PMCID: PMC8821042 DOI: 10.1016/j.ekir.2021.11.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Individuals with focal segmental glomerular sclerosis (FSGS) typically undergo kidney biopsy only once, which limits the ability to characterize kidney cell gene expression over time. METHODS We used single-cell RNA sequencing (scRNA-seq) to explore disease-related molecular signatures in urine cells from subjects with FSGS. We collected 17 urine samples from 12 FSGS subjects and captured these as 23 urine cell samples. The inflammatory signatures from renal epithelial and immune cells were evaluated in bulk gene expression data sets of FSGS and minimal change disease (MCD) (The Nephrotic Syndrome Study Network [NEPTUNE] study) and an immune single-cell data set from lupus nephritis (Accelerating Medicines Partnership). RESULTS We identified immune cells, predominantly monocytes, and renal epithelial cells in the urine. Further analysis revealed 2 monocyte subtypes consistent with M1 and M2 monocytes. Shed podocytes in the urine had high expression of marker genes for epithelial-to-mesenchymal transition (EMT). We selected the 16 most highly expressed genes from urine immune cells and 10 most highly expressed EMT genes from urine podocytes as immune signatures and EMT signatures, respectively. Using kidney biopsy transcriptomic data from NEPTUNE, we found that urine cell immune signature and EMT signature genes were more highly expressed in FSGS biopsies compared with MCD biopsies. CONCLUSION The identification of monocyte subsets and podocyte expression signatures in the urine samples of subjects with FSGS suggests that urine cell profiling might serve as a diagnostic and prognostic tool in nephrotic syndrome. Furthermore, this approach may aid in the development of novel biomarkers and identifying personalized therapies targeting particular molecular pathways in immune cells and podocytes.
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Affiliation(s)
- Khun Zaw Latt
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Jurgen Heymann
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph H. Jessee
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Avi Z. Rosenberg
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Celine C. Berthier
- Division of Nephrology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Michigan, USA
| | - Arnon Arazi
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA
| | - Sean Eddy
- Division of Nephrology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Michigan, USA
| | - Teruhiko Yoshida
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Yongmei Zhao
- Advanced Biomedical and Computational Sciences, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., National Cancer Institute, Frederick, Maryland, USA
| | - Vicky Chen
- Advanced Biomedical and Computational Sciences, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., National Cancer Institute, Frederick, Maryland, USA
| | - George W. Nelson
- Advanced Biomedical and Computational Sciences, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., National Cancer Institute, Frederick, Maryland, USA
| | - Margaret Cam
- Advanced Biomedical and Computational Sciences, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., National Cancer Institute, Frederick, Maryland, USA
| | - Parimal Kumar
- Center for Cancer Research Sequencing Facility, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland, USA
| | - Monika Mehta
- Center for Cancer Research Sequencing Facility, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland, USA
| | - Michael C. Kelly
- Cancer Research Technology Program, Single-Cell Analysis Facility, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
| | - Matthias Kretzler
- Division of Nephrology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Michigan, USA
| | - The Nephrotic Syndrome Study Network (NEPTUNE)
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
- Division of Nephrology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Michigan, USA
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA
- Advanced Biomedical and Computational Sciences, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., National Cancer Institute, Frederick, Maryland, USA
- Center for Cancer Research Sequencing Facility, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland, USA
- Cancer Research Technology Program, Single-Cell Analysis Facility, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
- Department of Pediatrics, Child Health Research Center, University of Virginia, Charlottesville, Virginia, USA
- Division of Nephrology, Children’s National Hospital, Washington, District of Columbia, USA
- Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
- Section on Pediatric Nephrology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- Department of Pediatrics, Uniformed Services University, Bethesda, Maryland, USA
- Division of Kidney Disease and Hypertension, The George Washington University School of Medicine and Health Sciences, Washington DC, USA
- Department of Medicine, Renal Electrolyte and Hypertension Division, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Basic Research Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - The Accelerating Medicines Partnership in Rheumatoid Arthritis and Systemic Lupus Erythematosus (AMP RA/SLE) Consortium
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
- Division of Nephrology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Michigan, USA
- The Feinstein Institute for Medical Research, Northwell Health, Manhasset, New York, USA
- Advanced Biomedical and Computational Sciences, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., National Cancer Institute, Frederick, Maryland, USA
- Center for Cancer Research Sequencing Facility, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, Maryland, USA
- Cancer Research Technology Program, Single-Cell Analysis Facility, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, USA
- Department of Pediatrics, Child Health Research Center, University of Virginia, Charlottesville, Virginia, USA
- Division of Nephrology, Children’s National Hospital, Washington, District of Columbia, USA
- Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
- Section on Pediatric Nephrology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- Department of Pediatrics, Uniformed Services University, Bethesda, Maryland, USA
- Division of Kidney Disease and Hypertension, The George Washington University School of Medicine and Health Sciences, Washington DC, USA
- Department of Medicine, Renal Electrolyte and Hypertension Division, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Basic Research Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Patricio E. Ray
- Department of Pediatrics, Child Health Research Center, University of Virginia, Charlottesville, Virginia, USA
| | - Marva Moxey-Mims
- Division of Nephrology, Children’s National Hospital, Washington, District of Columbia, USA
- Department of Pediatrics, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
| | - Gregory H. Gorman
- Section on Pediatric Nephrology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- Department of Pediatrics, Uniformed Services University, Bethesda, Maryland, USA
| | - Brent L. Lechner
- Section on Pediatric Nephrology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- Department of Pediatrics, Uniformed Services University, Bethesda, Maryland, USA
| | - Renu Regunathan-Shenk
- Division of Kidney Disease and Hypertension, The George Washington University School of Medicine and Health Sciences, Washington DC, USA
| | - Dominic S. Raj
- Division of Kidney Disease and Hypertension, The George Washington University School of Medicine and Health Sciences, Washington DC, USA
| | - Katalin Susztak
- Department of Medicine, Renal Electrolyte and Hypertension Division, Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cheryl A. Winkler
- Basic Research Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Jeffrey B. Kopp
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
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Du C, Ren Y, Li G, Yang Y, Yan Z, Yao F. Single Cell Transcriptome Helps Better Understanding Crosstalk in Diabetic Kidney Disease. Front Med (Lausanne) 2021; 8:657614. [PMID: 34485320 PMCID: PMC8415842 DOI: 10.3389/fmed.2021.657614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 07/26/2021] [Indexed: 12/20/2022] Open
Abstract
Years of research revealed that crosstalk extensively existed among kidney cells, cell factors and metabolites and played an important role in the development of diabetic kidney disease (DKD). In the last few years, single-cell RNA sequencing (scRNA-seq) technology provided new insight into cellular heterogeneity and genetic susceptibility regarding DKD at cell-specific level. The studies based on scRNA-seq enable a much deeper understanding of cell-specific processes such as interaction between cells. In this paper, we aim to review recent progress in single cell transcriptomic analyses of DKD, particularly highlighting on intra- or extra-glomerular cell crosstalk, cellular targets and potential therapeutic strategies for DKD.
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Affiliation(s)
- Chunyang Du
- Key Laboratory of Kidney Diseases of Hebei Province, Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Yunzhuo Ren
- Key Laboratory of Kidney Diseases of Hebei Province, Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Guixin Li
- Department of Burn, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yan Yang
- Key Laboratory of Kidney Diseases of Hebei Province, Department of Pathology, Hebei Medical University, Shijiazhuang, China
| | - Zhe Yan
- Department of Nephrology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Fang Yao
- Key Laboratory of Kidney Diseases of Hebei Province, Department of Pathology, Hebei Medical University, Shijiazhuang, China
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Parietal epithelial cell dysfunction in crescentic glomerulonephritis. Cell Tissue Res 2021; 385:345-354. [PMID: 34453566 PMCID: PMC8523405 DOI: 10.1007/s00441-021-03513-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 07/15/2021] [Indexed: 12/12/2022]
Abstract
Crescentic glomerulonephritis represents a group of kidney diseases characterized by rapid loss of kidney function and the formation of glomerular crescents. While the role of the immune system has been extensively studied in relation to the development of crescents, recent findings show that parietal epithelial cells play a key role in the pathophysiology of crescent formation, even in the absence of immune modulation. This review highlights our current understanding of parietal epithelial cell biology and the reported physiological and pathological roles that these cells play in glomerular lesion formation, especially in the context of crescentic glomerulonephritis.
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Ye C, Xiong W, Lei CT, Tang H, Su H, Yi F, Zhang C. MAD2B contributes to parietal epithelial cell activation and crescentic glomerulonephritis via Skp2. Am J Physiol Renal Physiol 2020; 319:F636-F646. [PMID: 32830536 DOI: 10.1152/ajprenal.00216.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Mitotic spindle assembly checkpoint protein 2 (MAD2B), a well-known anaphase-promoting complex/cyclosome (APC/C) inhibitor and a small subunit of DNA polymerase-ζ, is critical for mitotic control and DNA repair. Previously, we detected a strong increase of MAD2B in the glomeruli from patients with crescentic glomerulonephritis and anti-glomerular basement membrane (anti-GBM) rats, which predominantly originated from activated parietal epithelial cells (PECs). Consistently, in vitro MAD2B was increased in TNF-α-treated PECs, along with cell activation and proliferation, as well as extracellular matrix accumulation, which could be reversed by MAD2B genetic depletion. Furthermore, we found that expression of S phase kinase-associated protein 2 (Skp2), an APC/CCDH1 substrate, was increased in the glomeruli of anti-GBM rats, and TNF-α-stimulated PECs and could be suppressed by MAD2B depletion. Additionally, genetic deletion of Skp2 inhibited TNF-α-induced PEC activation and dysfunction. Finally, TNF-α blockade or glucocorticoid therapy administered to anti-GBM rats could ameliorate MAD2B and Skp2 accumulation as well as weaken PEC activation. Collectively, our data suggest that MAD2B has a pivotal role in the pathogenesis of glomerular PEC activation and crescent formation through induction of Skp2 expression.
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Affiliation(s)
- Chen Ye
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Xiong
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chun-Tao Lei
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Tang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hua Su
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fan Yi
- Department of Pharmacology, School of Basic Medical Science, Shandong University, Jinan, China
| | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Hamatani H, Eng DG, Hiromura K, Pippin JW, Shankland SJ. CD44 impacts glomerular parietal epithelial cell changes in the aged mouse kidney. Physiol Rep 2020; 8:e14487. [PMID: 32597007 PMCID: PMC7322268 DOI: 10.14814/phy2.14487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 05/17/2020] [Indexed: 02/06/2023] Open
Abstract
CD44 contributes to the activation of glomerular parietal epithelial cells (PECs). Although CD44 expression is higher in PECs of healthy aged mice, the biological role of CD44 in PECs in this context remains unclear. Accordingly, young (4 months) and aged (24 months) CD44-/- mice were compared to age-matched CD44+/+ mice, both aged in a nonstressed environment. Parietal epithelial cell densities were similar in both young and aged CD44+/+ and CD44-/- mice. Phosphorylated ERK 1/2 (pERK) was higher in aged CD44+/+ mice. Vimentin and α-SMA, markers of changes to the epithelial cell phenotype, were present in PECs in aged CD44+/+ mice, but absent in aged CD44-/- mice in both outer cortical (OC) and juxtamedullary (JM) glomeruli. Because age-related glomerular hypertrophy was lower in CD44-/- mice, mTOR activation was assessed by phospho-S6 ribosomal protein (pS6RP) staining. Parietal epithelial cells and glomerular tuft staining for pS6RP was lower in aged CD44-/- mice compared to aged CD44+/+ mice. Podocyte density was higher in aged CD44-/- mice in both OC and JM glomeruli. These changes were accompanied by segmental and global glomerulosclerosis in aged CD44+/+ mice, but absent in aged CD44-/- mice. These results show that the increase in CD44 in PECs in aged kidneys contributes to several changes to the glomerulus during healthy aging in mice, and may involve ERK and mTOR activation.
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Affiliation(s)
- Hiroko Hamatani
- Division of NephrologyUniversity of Washington School of MedicineSeattleWAUSA
- Department of Nephrology and RheumatologyGunma University Graduate School of MedicineMaebashiJapan
| | - Diana G. Eng
- Division of NephrologyUniversity of Washington School of MedicineSeattleWAUSA
| | - Keiju Hiromura
- Department of Nephrology and RheumatologyGunma University Graduate School of MedicineMaebashiJapan
| | - Jeffrey W. Pippin
- Division of NephrologyUniversity of Washington School of MedicineSeattleWAUSA
| | - Stuart J. Shankland
- Division of NephrologyUniversity of Washington School of MedicineSeattleWAUSA
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11
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Wrede C, Hegermann J, Mühlfeld C. Novel cell contact between podocyte microprojections and parietal epithelial cells analyzed by volume electron microscopy. Am J Physiol Renal Physiol 2020; 318:F1246-F1251. [PMID: 32249613 DOI: 10.1152/ajprenal.00097.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Podocytes are highly specialized cells with a clear cell polarity. It is known that in health and disease, microvilli protrude from the apical surface of the podocytes into the urinary space. As a basis to better understand the podocyte microprojections/microvilli, the present study analyzed their spatial localization, extension, and contact site with parietal epithelial cells (PECs). Using different electron microscopic (EM) techniques, we analyzed renal corpuscles of healthy young adult male C57BL/6 mice fixed by vascular perfusion. Serial block-face scanning EM was used to visualize entire corpuscles, focused ion beam scanning EM was performed to characterize microprojection/microvilli-rich regions at higher magnification, and transmission EM of serial sections was used to analyze the contact zone between podocyte microprojections and PECs. Numerous microprojections originating from the primary processes of podocytes were present in the urinary space in all regions of the corpuscle. They often reached the apical surface of the PEC but did not make junctional contacts. At high resolution, it was observed that the glycocalyx of both cells was in contact. Depending on the distance between podocytes and PECs, these microprojections had a stretched or coiled state. The present study shows that microprojections/microvilli of podocytes are a physiological feature of healthy mouse kidneys and are frequently in contact with the apical surface of PECs, thus spanning the urinary space. It is proposed that podocyte microprojections serve mechanosensory or communicative functions between podocytes and PECs.
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Affiliation(s)
- Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Jan Hegermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany.,Research Core Unit Electron Microscopy, Hannover Medical School, Hannover, Germany
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12
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Ectopic expression of CLDN2 in podocytes is associated with childhood onset nephrotic syndrome. Pediatr Res 2019; 86:485-491. [PMID: 31086291 DOI: 10.1038/s41390-019-0423-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/19/2019] [Accepted: 04/24/2019] [Indexed: 11/08/2022]
Abstract
BACKGROUND Animal models of nephrotic syndrome (NS) revealed that tight junction (TJ)-like structures are generated together with a concomitant decrease in slit diaphragms (SDs). Claudins (CLDNs) are capable of forming TJ strands and thereby the backbone of TJs. We showed the ectopic expression of CLDN2 in podocytes in pediatric NS, and detected its localization. METHODS Renal frozen specimens were obtained by biopsy from 49 pediatric patients: 21 subjects with MCD, 18 with FSGS, and 10 with IgA nephritis (IgA-N). CLDN2 expression was observed by immunohistochemistry and the CLDN2-positive area was calculated. Moreover, its localization was detected using immunoelectron microscopy. RESULTS CLDN2 is ectopically detected in cases with MCD and FSGS before remission. The CLDN2-stained region in MCD and FSGS glomeruli before remission was significantly greater than that after remission as well as in IgA-N patients. Immunoelectron microscopy revealed that CLDN2 was concentrated along newly formed TJs in podocytes. CONCLUSION The same pathological findings in terms of ectopic CLDN2 expression in podocytes were shown in cases with MCD and FSGS before remission. Immunofluorescence and immunoelectron studies of CLDN2 appear to afford a powerful tool for the diagnosis of primary NS. In addition, CLDN2 expression level may be related to disease status.
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13
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Tan H, Yi H, Zhao W, Ma JX, Zhang Y, Zhou X. Intraglomerular crosstalk elaborately regulates podocyte injury and repair in diabetic patients: insights from a 3D multiscale modeling study. Oncotarget 2018; 7:73130-73146. [PMID: 27683034 PMCID: PMC5341968 DOI: 10.18632/oncotarget.12233] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 09/12/2016] [Indexed: 11/30/2022] Open
Abstract
Podocytes are mainly involved in the regulation of glomerular filtration rate (GFR) under physiological condition. Podocyte depletion is a crucial pathological alteration in diabetic nephropathy (DN) and results in a broad spectrum of clinical syndromes such as protein urine and renal insufficiency. Recent studies indicate that depleted podocytes can be regenerated via differentiation of the parietal epithelial cells (PECs), which serve as the local progenitors of podocytes. However, the podocyte regeneration process is regulated by a complicated mechanism of cell-cell interactions and cytokine stimulations, which has been studied in a piecemeal manner rather than systematically. To address this gap, we developed a high-resolution multi-scale multi-agent mathematical model in 3D, mimicking the in situ glomerulus anatomical structure and micro-environment, to simulate the podocyte regeneration process under various cytokine perturbations in healthy and diabetic conditions. Our model showed that, treatment with pigment epithelium derived factor (PEDF) or insulin-like growth factor-1 (IGF-1) alone merely ameliorated the glomerulus injury, while co-treatment with both cytokines replenished the damaged podocyte population gradually. In addition, our model suggested that continuous administration of PEDF instead of a bolus injection sustained the regeneration process of podocytes. Part of the results has been validated by our in vivo experiments. These results indicated that amelioration of the glomerular stress by PEDF and promotion of PEC differentiation by IGF-1 are equivalently critical for podocyte regeneration. Our 3D multi-scale model represents a powerful tool for understanding the signaling regulation and guiding the design of cytokine therapies in promoting podocyte regeneration.
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Affiliation(s)
- Hua Tan
- Center for Bioinformatics and Systems Biology, Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Hualin Yi
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China.,Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Weiling Zhao
- Center for Bioinformatics and Systems Biology, Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Jian-Xing Ma
- Department of Physiology, University of Oklahoma College of Medicine, Oklahoma, OK 73104, USA
| | - Yuanyuan Zhang
- Institute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Xiaobo Zhou
- Center for Bioinformatics and Systems Biology, Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.,College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China
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14
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Lacy ER, Reale E. A unique juxtaglomerular apparatus in the river ray, Potamotrygon humerosa, a freshwater stingray. ZOOMORPHOLOGY 2017. [DOI: 10.1007/s00435-017-0372-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Multiple Targets for Novel Therapy of FSGS Associated with Circulating Permeability Factor. BIOMED RESEARCH INTERNATIONAL 2017; 2017:6232616. [PMID: 28951873 PMCID: PMC5603123 DOI: 10.1155/2017/6232616] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 05/10/2017] [Accepted: 06/15/2017] [Indexed: 01/13/2023]
Abstract
A plasma component is responsible for altered glomerular permeability in patients with focal segmental glomerulosclerosis. Evidence includes recurrence after renal transplantation, remission after plasmapheresis, proteinuria in infants of affected mothers, transfer of proteinuria to experimental animals, and impaired glomerular permeability after exposure to patient plasma. Therapy may include decreasing synthesis of the injurious agent, removing or blocking its interaction with cells, or blocking signaling or enhancing cell defenses to restore the permeability barrier and prevent progression. Agents that may prevent the synthesis of the permeability factor include cytotoxic agents or aggressive chemotherapy. Extracorporeal therapies include plasmapheresis, immunoadsorption with protein A or anti-immunoglobulin, or lipopheresis. Oral or intravenous galactose also decreases Palb activity. Studies of glomeruli have shown that several strategies prevent the action of FSGS sera. These include blocking receptor-ligand interactions, modulating cell reactions using indomethacin or eicosanoids 20-HETE or 8,9-EET, and enhancing cytoskeleton and protein interactions using calcineurin inhibitors, glucocorticoids, or rituximab. We have identified cardiotrophin-like cytokine factor 1 (CLCF-1) as a candidate for the permeability factor. Therapies specific to CLCF-1 include potential use of cytokine receptor-like factor (CRLF-1) and inhibition of Janus kinase 2. Combined therapy using multiple modalities offers therapy to reverse proteinuria and prevent scarring.
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16
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Abstract
The glomerulus has 3 resident cells namely mesangial cells that produce the mesangial matrix, endothelial cells that line the glomerular capillaries, and podocytes that cover the outer surface of the glomerular basement membrane. Parietal epithelial cells (PrECs), which line the Bowman's capsule are not part of the glomerular tuft but may have an important role in the normal function of the glomerulus. A significant progress has been made in recent years regarding our understanding of the role and function of these cells in normal kidney and in kidneys with various types of glomerulopathy. In crescentic glomerulonephritis necrotizing injury of the glomerular tuft results in activation and leakage of fibrinogen which provides the trigger for excessive proliferation of PrECs giving rise to glomerular crescents. In cases of collapsing glomerulopathy, podocyte injury causes collapse of the glomerular capillaries and activation and proliferation of PrECs, which accumulate within the urinary space in the form of pseudocrescents. Many of the noninflammatory glomerular lesions such as focal segmental glomerulosclerosis and global glomerulosclerosis also result from podocyte injury which causes variable loss of podocytes. In these cases podocyte injury leads to activation of PrECs that extend on to the glomerular tuft where they cause segmental and/or global sclerosis by producing excess matrix, resulting in obliteration of the capillary lumina. In diabetic nephropathy, in addition to increased matrix production in the mesangium and glomerular basement membranes, increased loss of podocytes is an important determinant of long-term prognosis. Contrary to prior belief there is no convincing evidence for an active podocyte proliferation in any of the above mentioned glomerulopathies.
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17
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Claudins in barrier and transport function-the kidney. Pflugers Arch 2016; 469:105-113. [PMID: 27878608 DOI: 10.1007/s00424-016-1906-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 01/12/2023]
Abstract
Claudins are discovered to be key players in renal epithelial physiology. They are involved in developmental, physiological, and pathophysiological differentiation. In the glomerular podocytes, claudin-1 is an important determinant of cell junction fate. In the proximal tubule, claudin-2 plays important roles in paracellular salt reabsorption. In the thick ascending limb, claudin-14, -16, and -19 regulate the paracellular reabsorption of calcium and magnesium. Recessive mutations in claudin-16 or -19 cause an inherited calcium and magnesium losing disease. Synonymous variants in claudin-14 have been associated with hypercalciuric nephrolithiasis by genome-wide association studies (GWASs). More importantly, claudin-14 gene expression can be regulated by extracellular calcium levels via the calcium sensing receptor. In the distal tubules, claudin-4 and -8 form paracellular chloride pathway to facilitate electrogenic sodium reabsorption. Aldosterone, WNK4, Cap1, and KLHL3 are powerful regulators of claudin and the paracellular chloride permeability. The lessons learned on claudins from the kidney will have a broader impact on tight junction biology in other epithelia and endothelia.
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18
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Yamazaki T, Sasaki S, Okamoto T, Sato Y, Hayashi A, Ariga T. Up-Regulation of CD74 Expression in Parietal Epithelial Cells in a Mouse Model of Focal Segmental Glomerulosclerosis. Nephron Clin Pract 2016; 134:238-252. [PMID: 27463800 DOI: 10.1159/000448221] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 07/04/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS De novo expression of CD44 is considered as a marker of parietal epithelial cell (PEC) activation. The aim of our study was to explore CD74 expression, which can form a complex with CD44, in PECs during the progression of focal segmental glomerulosclerosis (FSGS). To clarify the role of CD74 expression and of its interaction with CD44, we generated a new mouse model with enhanced PEC activation through lipopolysaccharide (LPS) application to adriamycin (ADR)-induced nephropathy mice (LPS-treated ADR mice). METHODS As a new model, LPS was intraperitoneally injected into the mice 3 weeks after ADR injection. The mice were divided into 3 categories: control mice, ADR mice and LPS-treated ADR mice. Renal function parameters, histologic changes and immunohistochemical expression of CD74 and other PEC activation markers were analyzed after LPS application. RESULTS After LPS stimulation, the glomeruli were characterized by enlarged epithelial cells with strong CD74 expression, followed by pseudo-crescent formation. By double staining, CD74-positive enlarged cells showed co-expression of classical PEC markers, but not of Lotus tetragonolobus lectin (marker of proximal tubular cells), suggesting amplification of PEC activation. Time-course analysis displayed marked upregulation of CD74 expression during rapid PEC activation compared with CD44. Additionally, the time-dependent change in ERK phosphorylation showed a similar pattern to CD74. CONCLUSION Our results indicate that CD74 can be a marker for PEC activation in FSGS. By modifying the ADR mouse model through LPS treatment, we found that CD74 upregulation better reflects a rapid amplification of PEC activation than CD44 expression.
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Affiliation(s)
- Takeshi Yamazaki
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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19
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McNicholas BA, Eng DG, Lichtnekert J, Rabinowitz PS, Pippin JW, Shankland SJ. Reducing mTOR augments parietal epithelial cell density in a model of acute podocyte depletion and in aged kidneys. Am J Physiol Renal Physiol 2016; 311:F626-39. [PMID: 27440779 PMCID: PMC5142165 DOI: 10.1152/ajprenal.00196.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/12/2016] [Indexed: 02/06/2023] Open
Abstract
Parietal epithelial cell (PEC) response to glomerular injury may underlie a common pathway driving fibrogenesis following podocyte loss that typifies several glomerular disorders. Although the mammalian target of rapamycin (mTOR) pathway is important in cell homeostasis, little is known of the biological role or impact of reducing mTOR activity on PEC response following podocyte depletion, nor in the aging kidney. The purpose of these studies was to determine the impact on PECs of reducing mTOR activity following abrupt experimental depletion in podocyte number, as well as in a model of chronic podocyte loss and sclerosis associated with aging. Podocyte depletion was induced by an anti-podocyte antibody and rapamycin started at day 5 until death at day 14 Reducing mTOR did not lead to a greater reduction in podocyte density, despite greater glomerulosclerosis. However, mTOR inhibition lead to an increase in PEC density and PEC-derived crescent formation. Additionally, markers of epithelial-to-mesenchymal transition (platelet-derived growth factor receptor-β, α-smooth muscle actin, Notch-3) and PEC activation (CD44, collagen IV) were further increased by mTOR reduction. Aged mice treated with rapamycin for 1, 2, and 10 wk before death at 26.5 mo (≈75-yr-old human age) had increased the number of glomeruli with a crescentic appearance. mTOR inhibition at either a high or low level lead to changes in PEC phenotype, indicating PEC morphology is sensitive to changes mediated by global mTOR inhibition.
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Affiliation(s)
| | - Diana G Eng
- Division of Nephrology, University of Washington, Seattle, Washington; and
| | - Julia Lichtnekert
- Division of Nephrology, University of Washington, Seattle, Washington; and
| | | | - Jeffrey W Pippin
- Division of Nephrology, University of Washington, Seattle, Washington; and
| | - Stuart J Shankland
- Division of Nephrology, University of Washington, Seattle, Washington; and
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20
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Lacy ER, Reale E, Luciano L. Immunohistochemical localization of renin-containing cells in two elasmobranch species. FISH PHYSIOLOGY AND BIOCHEMISTRY 2016; 42:995-1004. [PMID: 26746846 DOI: 10.1007/s10695-015-0191-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 12/28/2015] [Indexed: 06/05/2023]
Abstract
Renin immunoreactivity was localized at the light and electron microscopic level in two elasmobranch fish species, the Atlantic stingray, Dasyatis sabina, and river ray, Potamotrygon humerosa. At the light microscopic level, the peroxidase-anti-peroxidase method showed a positive immunoreactivity in modified smooth muscle cells in kidney afferent arterioles as well as in arterioles of several organs: rectal gland, inter-renal gland, conus arteriosus, and gill. Electron microscopic renin-positive immunogold localization was confined to the contents of membrane bound granules in the modified smooth muscle cells of these arterioles. The presence of renin-containing granules in the modified smooth muscle, "granular cells," of the renal glomerular afferent arteriole of these two stingray species adds support to earlier studies which showed the structural components of a complete juxtaglomerular apparatus and some of the biochemical and molecular components of a renin-angiotensin system (RAS) as found in teleost fish, reptiles, birds, and mammals. A notable result, however, was the renin-positive immunoreaction in the arteriolar wall of all other organs studied here. The presence of this "diffuse renin system" in the connective tissue of various organs suggests that in these two stingray species in addition to local organ-specific functions, the RAS may act as a systemic mechanism to regulate blood pressure and blood flow in the body.
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Affiliation(s)
- E R Lacy
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA.
| | - E Reale
- Department of Cell Biology, Center of Anatomy, Hannover Medical School, Hannover, Germany
| | - L Luciano
- Department of Cell Biology, Center of Anatomy, Hannover Medical School, Hannover, Germany
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21
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Abstract
Endothelin-1 (ET-1) is a 21-amino acid peptide with mitogenic and powerful vasoconstricting properties. Under healthy conditions, ET-1 is expressed constitutively in all cells of the glomerulus and participates in homeostasis of glomerular structure and filtration function. Under disease conditions, increases in ET-1 are critically involved in initiating and maintaining glomerular inflammation, glomerular basement membrane hypertrophy, and injury of podocytes (visceral epithelial cells), thereby promoting proteinuria and glomerulosclerosis. Here, we review the role of ET-1 in the function of glomerular endothelial cells, visceral (podocytes) and parietal epithelial cells, mesangial cells, the glomerular basement membrane, stromal cells, inflammatory cells, and mesenchymal stem cells. We also discuss molecular mechanisms by which ET-1, predominantly through activation of the ETA receptor, contributes to injury to glomerular cells, and review preclinical and clinical evidence supporting its pathogenic role in glomerular injury in chronic renal disease. Finally, the therapeutic rationale for endothelin antagonists as a new class of antiproteinuric drugs is discussed.
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Affiliation(s)
- Matthias Barton
- Molecular Internal Medicine, University of Zurich, Zurich, Switzerland.
| | - Andrey Sorokin
- Department of Medicine, Kidney Disease Center, Division of Nephrology, Medical College of Wisconsin, Milwaukee, WI
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22
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Hennedige T, Koh TS, Hartono S, Yan YY, Song IC, Zheng L, Lee WS, Rumpel H, Martarello L, Khoo JB, Koh DM, Chuang KH, Thng CH. Intravoxel incoherent imaging of renal fibrosis induced in a murine model of unilateral ureteral obstruction. Magn Reson Imaging 2015; 33:1324-1328. [PMID: 26248270 DOI: 10.1016/j.mri.2015.07.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 07/31/2015] [Indexed: 12/19/2022]
Abstract
PURPOSE To evaluate non-invasive imaging biomarkers for assessing renal fibrosis. DWI is used to assess renal function; intravoxel incoherent motion (IVIM) provides additional measures of perfusion-related diffusion (D*, blood flow; f, perfusion fraction). We aim to determine if reduced ADC seen in renal fibrosis is attributable to perfusion-related diffusion changes or to known reduction in tissue diffusivity (D). MATERIALS AND METHODS Unilateral ureteral obstruction (UUO) was created in six mice to induce renal fibrosis. DWI was performed the day before and 7 days post-UUO. A range of b-values from 0 to 1200 s/mm(2) were used. IVIM parameters were obtained using region of interests drawn over the renal parenchyma. Histopathological analysis of both kidneys was performed in all mice. Results were analyzed using the paired t-test with P<0.05 considered statistically significant. RESULTS D and f were significantly lower in the ligated kidneys at Day 7 compared to before ligation and no significant difference was found for D*. Comparing non-ligated and ligated kidneys within the same mouse at Day 7, significantly lower D values were observed in the ligated kidneys, while no significant difference was found for f and D*, although the values of f were generally lower. Histopathological analysis confirmed development of fibrosis and reduction in glomeruli in all the ligated kidneys at Day 7. CONCLUSION Our study shows that the reduction in ADC seen in renal fibrosis is attributable not only to reduced D as previously encountered but also a decrease in vascularity as assessed by f. Reduction in f is possibly related to a reduction in glomeruli.
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Affiliation(s)
| | - Tong San Koh
- Department of Oncologic Imaging, National Cancer Centre, Singapore
| | - Septian Hartono
- Department of Oncologic Imaging, National Cancer Centre, Singapore
| | - Yet Yen Yan
- Department of Oncologic Imaging, National Cancer Centre, Singapore
| | - In Chin Song
- SingHealth Experimental Medicine Centre, Singapore
| | - Lin Zheng
- SingHealth Experimental Medicine Centre, Singapore
| | - Wing Sum Lee
- SingHealth Experimental Medicine Centre, Singapore
| | | | | | - James B Khoo
- Department of Oncologic Imaging, National Cancer Centre, Singapore
| | | | | | - Choon Hua Thng
- Department of Oncologic Imaging, National Cancer Centre, Singapore
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Roeder SS, Stefanska A, Eng DG, Kaverina N, Sunseri MW, McNicholas BA, Rabinovitch P, Engel FB, Daniel C, Amann K, Lichtnekert J, Pippin JW, Shankland SJ. Changes in glomerular parietal epithelial cells in mouse kidneys with advanced age. Am J Physiol Renal Physiol 2015; 309:F164-78. [PMID: 26017974 DOI: 10.1152/ajprenal.00144.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 05/26/2015] [Indexed: 02/08/2023] Open
Abstract
Kidney aging is accompanied by characteristic changes in the glomerulus, but little is known about the effect of aging on glomerular parietal epithelial cells (PECs), nor if the characteristic glomerular changes in humans and rats also occur in very old mice. Accordingly, a descriptive analysis was undertaken in 27-mo-old C57B6 mice, considered advanced age. PEC density was significantly lower in older mice compared with young mice (aged 3 mo), and the decrease was more pronounced in juxtamedullary glomeruli compared with outer cortical glomeruli. In addition to segmental and global glomerulosclerosis in older mice, staining for matrix proteins collagen type IV and heparan sulfate proteoglycan were markedly increased in Bowman's capsules of older mouse glomeruli, consistent with increased extracellular matrix production by PECs. De novo staining for CD44, a marker of activated and profibrotic PECs, was significantly increased in aged glomeruli. CD44 staining was more pronounced in the juxtamedullary region and colocalized with phosphorylated ERK. Additionally, a subset of aged PECs de novo expressed the epithelial-to-mesenchymal transition markers α-smooth muscle and vimentin, with no changes in epithelial-to-mesenchymal transition markers E-cadherin and β-catenin. The mural cell markers neural/glial antigen 2, PDGF receptor-β, and CD146 as well as Notch 3 were also substantially increased in aged PECs. These data show that mice can be used to better understand the aging kidney and that PECs undergo substantial changes, especially in juxtamedullary glomeruli, that may participate in the overall decline in glomerular structure and function with advancing age.
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Affiliation(s)
- Sebastian S Roeder
- Division of Nephrology, University of Washington, Seattle, Washington; Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Ania Stefanska
- Division of Nephrology, University of Washington, Seattle, Washington
| | - Diana G Eng
- Division of Nephrology, University of Washington, Seattle, Washington
| | - Natalya Kaverina
- Division of Nephrology, University of Washington, Seattle, Washington
| | - Maria W Sunseri
- Division of Nephrology, University of Washington, Seattle, Washington
| | | | - Peter Rabinovitch
- Department of Pathology, University of Washington, Seattle, Washington
| | - Felix B Engel
- Department of Nephropathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; and
| | - Christoph Daniel
- Department of Nephropathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; and
| | - Kerstin Amann
- Department of Nephropathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; and
| | - Julia Lichtnekert
- Division of Nephrology, University of Washington, Seattle, Washington
| | - Jeffrey W Pippin
- Division of Nephrology, University of Washington, Seattle, Washington
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24
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Zhang Y, George J, Li Y, Olufade R, Zhao X. Matrix metalloproteinase-9 expression is enhanced in renal parietal epithelial cells of zucker diabetic Fatty rats and is induced by albumin in in vitro primary parietal cell culture. PLoS One 2015; 10:e0123276. [PMID: 25849723 PMCID: PMC4388686 DOI: 10.1371/journal.pone.0123276] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 02/18/2015] [Indexed: 11/18/2022] Open
Abstract
As a subfamily of matrix metalloproteinases (MMPs), gelatinases including MMP-2 and MMP-9 play an important role in remodeling and homeostasis of the extracellular matrix. However, conflicting results have been reported regarding their expression level and activity in the diabetic kidney. This study investigated whether and how MMP-9 expression and activity were changed in glomerular epithelial cells upon albumin overload. In situ zymography, immunostaining and Western blot for renal MMP gelatinolytic activity and MMP-9 protein expression were performed in Zucker lean and Zucker diabetic rats. Confocal microscopy revealed a focal increase in gelatinase activity and MMP-9 protein in the glomeruli of diabetic rats. Increased glomerular MMP-9 staining was mainly observed in hyperplastic parietal epithelial cells (PECs) expressing claudin-1 in the diabetic kidneys. Interestingly, increased parietal MMP-9 was often accompanied by decreased staining for podocyte markers (nephrin and podocalyxin) in the sclerotic area of affected glomeruli in diabetic rats. Additionally, urinary excretion of podocyte marker proteins was significantly increased in association with the levels of MMP-9 and albumin in the urine of diabetic animals. To evaluate the direct effect of albumin on expression and activity of MMP-9, primary cultured rat glomerular PECs were incubated with rat serum albumin (0.25 - 1 mg/ml) for 24 - 48 hrs. MMP-9 mRNA levels were significantly increased following albumin treatment. Meanwhile, albumin administration resulted in a dose-dependent increase in MMP-9 protein and activity in culture supernatants of PECs. Moreover, albumin activated p44/42 mitogen-activated protein kinase (MAPK) in PECs. Inhibition of p44/42 MAPK suppressed albumin-induced MMP-9 secretion from glomerular PECs. Taken together, we have demonstrated that an up-regulation of MMP-9 in activated parietal epithelium is associated with a loss of adjacent podocytes in progressive diabetic nephropathy. Albumin overload may induce MMP-9 expression and secretion by PECs via the activation of p44/42 MAPK pathway.
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MESH Headings
- Albumins/pharmacology
- Animals
- Blotting, Western
- Cells, Cultured
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/enzymology
- Diabetes Mellitus, Type 2/pathology
- Epithelial Cells/drug effects
- Epithelial Cells/enzymology
- Epithelial Cells/pathology
- Fluorescent Antibody Technique
- Immunoenzyme Techniques
- In Vitro Techniques
- Kidney Glomerulus/drug effects
- Kidney Glomerulus/enzymology
- Kidney Glomerulus/pathology
- Male
- Matrix Metalloproteinase 9/genetics
- Matrix Metalloproteinase 9/metabolism
- Podocytes/drug effects
- Podocytes/enzymology
- Podocytes/pathology
- RNA, Messenger/genetics
- Rats
- Rats, Zucker
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Yuanyuan Zhang
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, 30310, United States of America
| | - Jasmine George
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, 30310, United States of America
| | - Yun Li
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, 30310, United States of America
| | - Rebecca Olufade
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, 30310, United States of America
| | - Xueying Zhao
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, 30310, United States of America
- * E-mail:
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25
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New insights into glomerular parietal epithelial cell activation and its signaling pathways in glomerular diseases. BIOMED RESEARCH INTERNATIONAL 2015; 2015:318935. [PMID: 25866774 PMCID: PMC4383425 DOI: 10.1155/2015/318935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/28/2014] [Accepted: 09/01/2014] [Indexed: 12/26/2022]
Abstract
The glomerular parietal epithelial cells (PECs) have aroused an increasing attention recently. The proliferation of PECs is the main feature of crescentic glomerulonephritis; besides that, in the past decade, PEC activation has been identified in several types of noninflammatory glomerulonephropathies, such as focal segmental glomerulosclerosis, diabetic glomerulopathy, and membranous nephropathy. The pathogenesis of PEC activation is poorly understood; however, a few studies delicately elucidate the potential mechanisms and signaling pathways implicated in these processes. In this review we will focus on the latest observations and concepts about PEC activation in glomerular diseases and the newest identified signaling pathways in PEC activation.
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26
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Naito S, Pippin JW, Shankland SJ. The glomerular parietal epithelial cell's responses are influenced by SM22 alpha levels. BMC Nephrol 2014; 15:174. [PMID: 25376243 PMCID: PMC4247743 DOI: 10.1186/1471-2369-15-174] [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: 08/06/2014] [Accepted: 10/22/2014] [Indexed: 12/17/2022] Open
Abstract
Background Studies have shown in several diseases initially affecting podocytes, that the neighboring glomerular parietal epithelial cells (PECs) are secondarily involved. The PEC response might be reparative under certain circumstances, yet injurious under others. The factors governing these are not well understood. We have shown that SM22α, an actin-binding protein considered a marker of smooth muscle differentiation, is upregulated in podocytes and PECs in several models of podocyte disease. However, the impact of SM22α levels on PECs is not known. Methods Experimental glomerular disease, characterized by primary podocyte injury, was induced in aged-matched SM22α +/+ and SM22α -/- mice by intraperitoneal injection of sheep anti-rabbit glomeruli antibody. Immunostaining methods were employed on days 7 and 14 of disease. Results The number of PEC transition cells, defined as cells co-expressing a PEC protein (PAX2) and podocyte protein (Synaptopodin) was higher in diseased SM22α -/- mice compared with SM22α +/+ mice. WT1 staining along Bowman’s capsule is higher in diseased SM22α -/- mice. This was accompanied by increased PEC proliferation (measured by ki-67 staining), and an increase in immunostaining for the progenitor marker NCAM, in a subpopulation of PECs in diseased SM22α -/- mice. In addition, immunostaining for vimentin and alpha smooth muscle actin, markers of epithelial-to-mesenchymal transition (EMT), was lower in diseased SM22α -/- mice compared to diseased SM22α+/+ mice. Conclusion SM22α levels may impact how PECs respond following a primary podocyte injury in experimental glomerular disease. Absent/lower levels favor an increase in PEC transition cells and PECs expressing a progenitor marker, and a lower EMT rate compared to SM22α +/+ mice, where SM22 levels are markedly increased in PECs.
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Affiliation(s)
| | | | - Stuart J Shankland
- Division of Nephrology Department of Medicine, University of Washington School of Medicine, Box 356521, 1959 NE Pacific St,, Seattle, WA 98195-6521, USA.
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27
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Kietzmann L, Guhr SSO, Meyer TN, Ni L, Sachs M, Panzer U, Stahl RAK, Saleem MA, Kerjaschki D, Gebeshuber CA, Meyer-Schwesinger C. MicroRNA-193a Regulates the Transdifferentiation of Human Parietal Epithelial Cells toward a Podocyte Phenotype. J Am Soc Nephrol 2014; 26:1389-401. [PMID: 25270065 DOI: 10.1681/asn.2014020190] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 08/03/2014] [Indexed: 11/03/2022] Open
Abstract
Parietal epithelial cells have been identified as potential progenitor cells in glomerular regeneration, but the molecular mechanisms underlying this process are not fully defined. Here, we established an immortalized polyclonal human parietal epithelial cell (hPEC) line from naive human Bowman's capsule cells isolated by mechanical microdissection. These hPECs expressed high levels of PEC-specific proteins and microRNA-193a (miR-193a), a suppressor of podocyte differentiation through downregulation of Wilms' tumor 1 in mice. We then investigated the function of miR-193a in the establishment of podocyte and PEC identity and determined whether inhibition of miR-193a influences the behavior of PECs in glomerular disease. After stable knockdown of miR-193a, hPECs adopted a podocyte-like morphology and marker expression, with decreased expression levels of PEC markers. In mice, inhibition of miR-193a by complementary locked nucleic acids resulted in an upregulation of the podocyte proteins synaptopodin and Wilms' tumor 1. Conversely, overexpression of miR-193a in vivo resulted in the upregulation of PEC markers and the loss of podocyte markers in isolated glomeruli. Inhibition of miR-193a in a mouse model of nephrotoxic nephritis resulted in reduced crescent formation and decreased proteinuria. Together, these results show the establishment of a human PEC line and suggest that miR-193a functions as a master switch, such that glomerular epithelial cells with high levels of miR-193a adopt a PEC phenotype and cells with low levels of miR-193a adopt a podocyte phenotype. miR-193a-mediated maintenance of PECs in an undifferentiated reactive state might be a prerequisite for PEC proliferation and migration in crescent formation.
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Affiliation(s)
- Leonie Kietzmann
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sebastian S O Guhr
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias N Meyer
- Department of Internal Medicine, Nephrology, University Affiliated Asklepios Clinic Hamburg Barmbek, Hamburg, Germany
| | - Lan Ni
- Childrens Renal Unit, Bristol Royal Hospital for Children, Bristol, United Kingdom; and
| | - Marlies Sachs
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ulf Panzer
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rolf A K Stahl
- Department of Internal Medicine, Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Moin A Saleem
- Childrens Renal Unit, Bristol Royal Hospital for Children, Bristol, United Kingdom; and
| | - Dontscho Kerjaschki
- Department of Clinical Pathology, Medical University of Vienna, Vienna, Austria
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28
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Glomerular parietal epithelial cells in kidney physiology, pathology, and repair. Curr Opin Nephrol Hypertens 2014; 22:302-9. [PMID: 23518463 DOI: 10.1097/mnh.0b013e32835fefd4] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE OF REVIEW We have summarized recently published glomerular parietal epithelial cell (PEC) research, focusing on their roles in glomerular development and physiology, and in certain glomerular diseases. The rationale is that PECs have been largely ignored until the recent availability of cell lineage tracing studies, human and murine PEC culture systems, and potential therapeutic interventions of PECs. RECENT FINDINGS Several new paradigms involving PECs have emerged demonstrating their significant contribution to glomerular physiology and numerous glomerular diseases. A subset of PECs serving as podocyte progenitors have been identified in normal human glomeruli. They provide a source for podocytes in adolescent mice, and their numbers increase in states of podocyte depletion. PEC progenitor number is increased by retinoids and angiotensin-converting enzyme inhibition. However, dysregulated growth of PEC progenitors leads to pseudo-crescent and crescent formation. In focal segmental glomerulosclerosis, considered a podocyte disease, activated PECs increase extracellular matrix production, which leads to synechial attachment and, when they move to the glomerular tuft, to segmental glomerulosclerosis. Finally, PECs might be adversely affected in proteinuric states by undergoing apoptosis. SUMMARY PECs play a critical role in glomerular repair through their progenitor function, but under certain circumstances paradoxically contribute to deterioration by augmenting scarring and crescent formation.
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29
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Glomerular development--shaping the multi-cellular filtration unit. Semin Cell Dev Biol 2014; 36:39-49. [PMID: 25153928 DOI: 10.1016/j.semcdb.2014.07.016] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 01/09/2023]
Abstract
The glomerulus represents a highly structured filtration unit, composed of glomerular endothelial cells, mesangial cells, podocytes and parietal epithelial cells. During glomerulogenesis an intricate network of signaling pathways involving transcription factors, secreted factors and cell-cell communication is required to guarantee accurate evolvement of a functional, complex 3-dimensional glomerular architecture. Here, we want to provide an overview on the critical steps and relevant signaling cascades of glomerular development.
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30
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Transcriptional landscape of glomerular parietal epithelial cells. PLoS One 2014; 9:e105289. [PMID: 25127402 PMCID: PMC4134297 DOI: 10.1371/journal.pone.0105289] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 07/23/2014] [Indexed: 11/19/2022] Open
Abstract
Very little is known about the function of glomerular parietal epithelial cells (PECs). In this study, we performed genome-wide expression analysis on PEC-enriched capsulated vs. PEC-deprived decapsulated rat glomeruli to determine the transcriptional state of PECs under normal conditions. We identified hundreds of differentially expressed genes that mapped to distinct biologic modules including development, tight junction, ion transport, and metabolic processes. Since developmental programs were highly enriched in PECs, we characterized several of their candidate members at the protein level. Collectively, our findings confirm that PECs are multifaceted cells and help define their diverse functional repertoire.
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31
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Hamatani H, Hiromura K, Sakairi T, Takahashi S, Watanabe M, Maeshima A, Ohse T, Pippin JW, Shankland SJ, Nojima Y. Expression of a novel stress-inducible protein, sestrin 2, in rat glomerular parietal epithelial cells. Am J Physiol Renal Physiol 2014; 307:F708-17. [PMID: 25056347 DOI: 10.1152/ajprenal.00625.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sestrin 2, initially identified as a p53 target protein, accumulates in cells exposed to stress and inhibits mammalian target of rapamycin (mTOR) signaling. In normal rat kidneys, sestrin 2 was selectively expressed in parietal epithelial cells (PECs), identified by the marker protein gene product 9.5. In adriamycin nephropathy, sestrin 2 expression decreased in PECs on day 14, together with increased expression of phosphorylated S6 ribosomal protein (P-S6RP), a downstream target of mTOR. Sestrin 2 expression was markedly decreased on day 42, coinciding with glomerulosclerosis and severe periglomerular fibrosis. In puromycin aminonucleoside nephropathy, decreased sestrin 2 expression, increased P-S6RP expression, and periglomerular fibrosis were observed on day 9, when massive proteinuria developed. These changes were transient and nearly normalized by day 28. In crescentic glomerulonephritis, sestrin 2 expression was not detected in cellular crescents, whereas P-S6RP increased. In conditionally immortalized cultured PECs, the forced downregulation of sestrin 2 by short hairpin RNA resulted in increased expression of P-S6RP and increased apoptosis. These data suggest that sestrin 2 is involved in PEC homeostasis by regulating the activity of mTOR. In addition, sestrin 2 could be a novel marker of PECs, and decreased expression of sestrin 2 might be a marker of PEC injury.
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Affiliation(s)
- Hiroko Hamatani
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Keiju Hiromura
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan;
| | - Toru Sakairi
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Satoshi Takahashi
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Mitsuharu Watanabe
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Akito Maeshima
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Takamoto Ohse
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan; and
| | - Jeffery W Pippin
- Division of Nephrology, University of Washington, Seattle, Washington
| | | | - Yoshihisa Nojima
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
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32
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Yamada S, Nakamura J, Asada M, Takase M, Matsusaka T, Iguchi T, Yamada R, Tanaka M, Higashi AY, Okuda T, Asada N, Fukatsu A, Kawachi H, Graf D, Muso E, Kita T, Kimura T, Pastan I, Economides AN, Yanagita M. Twisted gastrulation, a BMP antagonist, exacerbates podocyte injury. PLoS One 2014; 9:e89135. [PMID: 24586548 PMCID: PMC3934867 DOI: 10.1371/journal.pone.0089135] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 01/20/2014] [Indexed: 12/12/2022] Open
Abstract
Podocyte injury is the first step in the progression of glomerulosclerosis. Previous studies have demonstrated the beneficial effect of bone morphogenetic protein 7 (Bmp7) in podocyte injury and the existence of native Bmp signaling in podocytes. Local activity of Bmp7 is controlled by cell-type specific Bmp antagonists, which inhibit the binding of Bmp7 to its receptors. Here we show that the product of Twisted gastrulation (Twsg1), a Bmp antagonist, is the central negative regulator of Bmp function in podocytes and that Twsg1 null mice are resistant to podocyte injury. Twsg1 was the most abundant Bmp antagonist in murine cultured podocytes. The administration of Bmp induced podocyte differentiation through Smad signaling, whereas the simultaneous administration of Twsg1 antagonized the effect. The administration of Bmp also inhibited podocyte proliferation, whereas simultaneous administration of Twsg1 antagonized the effect. Twsg1 was expressed in the glomerular parietal cells (PECs) and distal nephron of the healthy kidney, and additionally in damaged glomerular cells in a murine model of podocyte injury. Twsg1 null mice exhibited milder hypoalbuminemia and hyperlipidemia, and milder histological changes while maintaining the expression of podocyte markers during podocyte injury model. Taken together, our results show that Twsg1 plays a critical role in the modulation of protective action of Bmp7 on podocytes, and that inhibition of Twsg1 is a promising means of development of novel treatment for podocyte injury.
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Affiliation(s)
- Sachiko Yamada
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Jin Nakamura
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Misako Asada
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Masayuki Takase
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Taiji Matsusaka
- Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Taku Iguchi
- TMK Project, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan
| | - Ryo Yamada
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Mari Tanaka
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Atsuko Y. Higashi
- Deaprtment of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Tomohiko Okuda
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Nariaki Asada
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | | | - Hiroshi Kawachi
- Department of Cell Biology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Niigata, Japan
| | - Daniel Graf
- Institute of Oral Biology, Faculty of Medicine, University of Zurich, Zurich, Switzerland
| | - Eri Muso
- Department of Nephrology and Dialysis, Kitano Hospital, Tazuke Kofukai Medical Research Institute, Osaka, Osaka, Japan
| | - Toru Kita
- Kobe City Medical Center General Hospital, Kobe, Hyogo, Japan
| | - Takeshi Kimura
- Deaprtment of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
| | - Ira Pastan
- Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Aris N. Economides
- Regeneron Pharmaceuticals, Inc., Tarrytown, New York, United States of America
| | - Motoko Yanagita
- Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, Japan
- * E-mail:
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33
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Schulte K, Berger K, Boor P, Jirak P, Gelman IH, Arkill KP, Neal CR, Kriz W, Floege J, Smeets B, Moeller MJ. Origin of parietal podocytes in atubular glomeruli mapped by lineage tracing. J Am Soc Nephrol 2013; 25:129-41. [PMID: 24071005 DOI: 10.1681/asn.2013040376] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Parietal podocytes are fully differentiated podocytes lining Bowman's capsule where normally only parietal epithelial cells (PECs) are found. Parietal podocytes form throughout life and are regularly observed in human biopsies, particularly in atubular glomeruli of diseased kidneys; however, the origin of parietal podocytes is unresolved. To assess the capacity of PECs to transdifferentiate into parietal podocytes, we developed and characterized a novel method for creating atubular glomeruli by electrocoagulation of the renal cortex in mice. Electrocoagulation produced multiple atubular glomeruli containing PECs as well as parietal podocytes that projected from the vascular pole and lined Bowman's capsule. Notably, induction of cell death was evident in some PECs. In contrast, Bowman's capsules of control animals and normal glomeruli of electrocoagulated kidneys rarely contained podocytes. PECs and podocytes were traced by inducible and irreversible genetic tagging using triple transgenic mice (PEC- or Pod-rtTA/LC1/R26R). Examination of serial cryosections indicated that visceral podocytes migrated onto Bowman's capsule via the vascular stalk; direct transdifferentiation from PECs to podocytes was not observed. Similar results were obtained in a unilateral ureter obstruction model and in human diseased kidney biopsies, in which overlap of PEC- or podocyte-specific antibody staining indicative of gradual differentiation did not occur. These results suggest that induction of atubular glomeruli leads to ablation of PECs and subsequent migration of visceral podocytes onto Bowman's capsule, rather than transdifferentiation from PECs to parietal podocytes.
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Affiliation(s)
- Kevin Schulte
- Department of Nephrology and Immunology, RWTH University of Aachen, Aachen, NRW, Germany
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34
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Danger control programs cause tissue injury and remodeling. Int J Mol Sci 2013; 14:11319-46. [PMID: 23759985 PMCID: PMC3709734 DOI: 10.3390/ijms140611319] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 05/12/2013] [Accepted: 05/22/2013] [Indexed: 02/07/2023] Open
Abstract
Are there common pathways underlying the broad spectrum of tissue pathologies that develop upon injuries and from subsequent tissue remodeling? Here, we explain the pathophysiological impact of a set of evolutionary conserved danger control programs for tissue pathology. These programs date back to the survival benefits of the first multicellular organisms upon traumatic injuries by launching a series of danger control responses, i.e., 1. Haemostasis, or clotting to control bleeding; 2. Host defense, to control pathogen entry and spreading; 3. Re-epithelialisation, to recover barrier functions; and 4. Mesenchymal, to repair to regain tissue stability. Taking kidney pathology as an example, we discuss how clotting, inflammation, epithelial healing, and fibrosis/sclerosis determine the spectrum of kidney pathology, especially when they are insufficiently activated or present in an overshooting and deregulated manner. Understanding the evolutionary benefits of these response programs may refine the search for novel therapeutic targets to limit organ dysfunction in acute injuries and in progressive chronic tissue remodeling.
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35
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The expression of podocyte-specific proteins in parietal epithelial cells is regulated by protein degradation. Kidney Int 2013; 84:532-44. [PMID: 23615505 DOI: 10.1038/ki.2013.115] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 01/23/2013] [Accepted: 01/24/2013] [Indexed: 11/08/2022]
Abstract
The role of parietal epithelial cells (PECs) in glomerular disease is unclear because they also express podocyte proteins under pathophysiological conditions. To help resolve this, we established a novel PEC isolation technique in rats and mice to investigate which regulatory mechanisms lead to podocyte protein expression in PECs. This pure pool of naive PECs was then compared with PECs in primary culture and immortalized PECs in permanent culture. The naive PECs expressed low levels of podocyte-specific mRNA. Accordingly, in crescentic glomerulonephritis, single PECs activated the podocin promoter in vivo. In primary culture, PECs expressed a distinct morphology from podocytes but with high transcript and protein levels of PEC markers. In contrast to naive PECs, cultured PECs also expressed podocyte proteins, and this correlated with reduced proteolytic activity but not with increased transcript levels. Activation of autophagy or proteasomal degradation decreased the levels of podocyte proteins in PECs, whereas inhibition of proteasomal degradation led to the stabilization of podocyte proteins in PECs. Thus, naive PECs express podocyte transcripts physiologically and these podocyte proteins are stable under pathological conditions through decreased proteolysis.
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36
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Denis CJ, Van Acker N, De Schepper S, De Bie M, Andries L, Fransen E, Hendriks D, Kockx MM, Lambeir AM. Mapping of carboxypeptidase m in normal human kidney and renal cell carcinoma: expression in tumor-associated neovasculature and macrophages. J Histochem Cytochem 2012; 61:218-35. [PMID: 23172796 DOI: 10.1369/0022155412470456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Although the kidney generally has been regarded as an excellent source of carboxypeptidase M (CPM), little is known about its renal-specific expression level and distribution. This study provides a detailed localization of CPM in healthy and diseased human kidneys. The results indicate a broad distribution of CPM along the renal tubular structures in the healthy kidney. CPM was identified at the parietal epithelium beneath the Bowman's basement membrane and in glomerular mesangial cells. Capillaries, podocytes, and most interstitial cells were CPM negative. Tumor cells of renal cell carcinoma subtypes lose CPM expression upon dedifferentiation. Tissue microarray analysis demonstrated a correlation between low CPM expression and tumor cell type. CPM staining was intense on phagocytotic tumor-associated macrophages. Immunoreactive CPM was also detected in the tumor-associated vasculature. The absence of CPM in normal renal blood vessels points toward a role for CPM in angiogenesis. Coexistence of CPM and the epidermal growth factor receptor (EGFR) was detected in papillary renal cell carcinoma. However, the different subcellular localization of CPM and EGFR argues against an interaction between these h proteins. The description of the distribution of CPM in human kidney forms the foundation for further study of the (patho)physiological activities of CPM in the kidney.
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37
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SSeCKS sequesters cyclin D1 in glomerular parietal epithelial cells and influences proliferative injury in the glomerulus. J Transl Med 2012; 92:499-510. [PMID: 22249313 DOI: 10.1038/labinvest.2011.199] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Glomerular parietal epithelial cells (PECs) are precursors to podocytes in mature glomeruli; however, as progenitors, the distinct intrinsic mechanisms that allow for repeated periods of cell-cycle arrest and re-entry of PECs after glomerulogenesis are unknown. Here, we show that the Src-suppressed protein kinase C substrate (SSeCKS), a multivalent scaffolding A kinase anchoring protein, sequesters cyclin D1 in the cytoplasm of quiescent PECs. SSeCKS expression is induced in embryonic PECs, but not in embryonic podocytes, starting at the S phase of glomerulogenesis, and is constitutively expressed postnatally by PECs, but not podocytes, in normal glomeruli. Cyclin D1 was immunoprecipitated with SSeCKS from capsulated glomeruli containing PECs, whereas decapsulated glomeruli without PECs lacked SSeCKS and cyclin D1. Cell-cell contact inhibition of proliferation in cultured PECs induced SSeCKS expression and binding of cyclin D1 by SSeCKS in the cytoplasm, whereas phosphorylation of SSeCKS by activated protein kinase C disrupted binding, resulting in nuclear translocation of cyclin D1. SSeCKS(-/-) mice showed hyperplasia of PECs in otherwise normal glomeruli and developed significantly worse proteinuric glomerular disease, marked by increased PEC proliferation and expression of nuclear cyclin D1, from nephrotoxic nephritis. These results suggest that SSeCKS controls the localization and activity of cyclin D1 in PECs and influences proliferative injury in the glomerulus.
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Lier N, Gresko N, Chiara M, Loffing-Cueni D, Loffing J. Immunofluorescent localization of the Rab-GAP protein TBC1D4 (AS160) in mouse kidney. Histochem Cell Biol 2012; 138:101-12. [DOI: 10.1007/s00418-012-0944-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2012] [Indexed: 10/28/2022]
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Zhang J, Hansen KM, Pippin JW, Chang AM, Taniguchi Y, Krofft RD, Pickering SG, Liu ZH, Abrass CK, Shankland SJ. De novo expression of podocyte proteins in parietal epithelial cells in experimental aging nephropathy. Am J Physiol Renal Physiol 2011; 302:F571-80. [PMID: 22129965 DOI: 10.1152/ajprenal.00516.2011] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A progressive decrease in podocyte number underlies the development of glomerulosclerosis and reduced kidney function in aging nephropathy. Recent data suggest that under certain disease states, parietal epithelial cells (PECs) begin to express proteins considered specific to podocytes. To determine whether this phenomenon increases in aging kidneys, 4-, 12-, and 20-mo ad libitum-fed and 20-mo calorie-restricted (CR) rats were studied. Single and double immunostaining were performed with antibodies to the PEC protein paired box gene 2 (PAX2) and tight junction protein claudin-1, the podocyte-specific protein Wilms' tumor 1 (WT-1), and the proliferating cell protein (Ki-67). ImageJ software measured Bowman's basement membrane (BBM) length and glomerular tuft area in individual glomeruli from each animal to assess glomerular size. The results showed that in aged ad libitum rats, the decrease in number of podocytes/glomerular tuft area was accompanied by an increase in the number of PECs/BBM length at 12 and 20 mo (P < 0.01 vs. 4 mo). The increase in PEC number was due to proliferation (increase in PAX2/Ki-67 double-positive cells). Aging was accompanied by a progressive increase in the number of glomerular cells double staining for PAX2 and WT-1. In contrast, the control 20-mo-old CR rats had no increase in glomerular size, and podocyte and PEC number were not altered. These results suggest that although the number of PECs and PECs expressing podocyte proteins increase in aging nephropathy, they are likely not sufficient to compensate for the decrease in podocyte number.
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Affiliation(s)
- Jiong Zhang
- Div. of Nephrology, Dept. of Medicine, Univ. of Washington School of Medicine, Seattle, WA 98195-6521, USA
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Chang AM, Ohse T, Krofft RD, Wu JS, Eddy AA, Pippin JW, Shankland SJ. Albumin-induced apoptosis of glomerular parietal epithelial cells is modulated by extracellular signal-regulated kinase 1/2. Nephrol Dial Transplant 2011; 27:1330-43. [PMID: 21896500 DOI: 10.1093/ndt/gfr483] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The biological role(s) of glomerular parietal epithelial cells (PECs) is not fully understood in health or disease. Given its location, PECs are constantly exposed to low levels of filtered albumin, which is increased in nephrotic states. We tested the hypothesis that PECs internalize albumin and increased uptake results in apoptosis. METHODS Confocal microscopy of immunofluorescent staining and immunohistochemistry were used to demonstrate albumin internalization in PECs and to quantitate albumin uptake in normal mice and rats as well as experimental models of membranous nephropathy, minimal change disease/focal segmental glomerulosclerosis and protein overload nephropathy. Fluorescence-activated cell sorting analysis was performed on immortalized cultured PECs exposed to fluorescein isothiocyanate (FITC)-labeled albumin in the presence of an endosomal inhibitor or vehicle. Apoptosis was measured by Hoechst staining in cultured PECs exposed to bovine serum albumin. Levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (p-ERK1/2) were restored by retroviral infection of mitogen-activated protein kinase (MEK) 1/2 and reduced by U0126 in PECs exposed to high albumin levels in culture and apoptosis measured by Hoechst staining. RESULTS PECs internalized albumin normally, and this was markedly increased in all of the experimental disease models (P<0.05 versus controls). Cultured immortalized PECs also internalize FITC-labeled albumin, which was reduced by endosomal inhibition. A consequence of increased albumin internalization was PEC apoptosis in vitro and in vivo. Candidate signaling pathways underlying these events were examined. Data showed markedly reduced levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (ERK1/2) in PECs exposed to high albumin levels in nephropathy and in culture. A role for ERK1/2 in limiting albumin-induced apoptosis was shown by restoring p-ERK1/2 by retroviral infection, which reduced apoptosis in cultured PECs, while a forced decrease of p-ERK1/2 through inhibition of MEK 1/2 significantly increased albumin-induced PEC apoptosis. CONCLUSIONS A normal role of PECs is to take up filtered albumin. However, this is increased in proteinuric glomerular diseases, leading to apoptosis through changes in ERK1/2.
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Affiliation(s)
- Alice M Chang
- University of Washington, and Seattle Children's Hospital and Research Institute, Seattle, WA, USA.
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Formation of atubular glomeruli in the developing kidney following chronic urinary tract obstruction. Pediatr Nephrol 2011; 26:1381-5. [PMID: 21222000 DOI: 10.1007/s00467-010-1748-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 12/08/2010] [Accepted: 12/14/2010] [Indexed: 10/18/2022]
Abstract
Congenital urinary tract obstruction is a major cause of progressive renal disease in children. We developed a model of partial unilateral ureteral obstruction (UUO) in the neonatal mouse, in which nephrogenesis at birth is similar to that of the midtrimester human fetus. The proximal tubule responds to UUO by undergoing apoptosis and necrosis, likely due to mitochondrial sensitivity to hypoxia and reactive oxygen species in the face of reduced endogenous antiapoptotic factors such as eNOS. Damage to the glomerulotubular junction is followed by scission and formation of atubular glomeruli and aglomerular tubules. This is an orchestrated process, with atubular glomeruli surrounded by a continuous layer of regenerated parietal epithelial cells. Relief of UUO at 7 days of age results in remodeling of the renal parenchyma by adulthood. In contrast to proximal tubular destruction, collecting ducts remain dilated and patent, with remodeling due to apoptosis and proliferation (a process associated with recruitment of intercalated cells as progenitor cells following UUO in the fetal monkey). Formation of atubular glomeruli occurs in other renal disorders (congenital nephrotic syndrome and cystinosis), and may represent a maladaptive response to proximal tubular injury reflecting an evolutionary adaptation by an ancestor we share with aglomerular marine fish.
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Shimizu A, Higo S, Fujita E, Mii A, Kaneko T. Focal segmental glomerulosclerosis after renal transplantation. Clin Transplant 2011; 25 Suppl 23:6-14. [PMID: 21623907 DOI: 10.1111/j.1399-0012.2011.01452.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a clinicopathologic syndrome of proteinuria, usually of nephrotic range, associated with focal and segmental sclerotic glomerular lesions. Therefore, FSGS is diagnosed by clinical features and histopathological examination of renal biopsy. The natural history of the condition varies, and although it may respond to treatment, FSGS is an important disease in the etiology of end-stage renal disease (ESRD). Furthermore, after kidney transplantation, approximately 30% of patients with FSGS develop recurrent FSGS. The risk factors for recurrence of FSGS include childhood onset and age <15 yr, rapid progression of the primary FSGS to ESRD, recurrence of FSGS in a previous allograft, diffuse mesangial hypercellularity in the native kidney, collapsing FSGS, and podocin gene mutation. In addition, after kidney transplantation, de novo FSGS also develops in approximately 10-20% of allografts, associated with a complication of hyperfiltration injury, chronic transplant glomerulopathy, and calcineurin inhibitor toxicity. FSGS is considered a podocyte disease, and the pathology is characterized by segmental FSGS lesion with glomerular epithelial hypercellularity. The pathological diagnosis of FSGS is based on the 2004 Columbia classification system. In the present minireview, we discuss the pathology of recurrence and de novo FSGS after kidney transplantation.
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Affiliation(s)
- Akira Shimizu
- Department of Pathology (Analytic Human Pathology), Nippon Medical School, Tokyo, Japan.
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Jefferson JA, Alpers CE, Shankland SJ. Podocyte biology for the bedside. Am J Kidney Dis 2011; 58:835-45. [PMID: 21715071 DOI: 10.1053/j.ajkd.2011.03.033] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Accepted: 03/03/2011] [Indexed: 12/14/2022]
Abstract
The explosion of podocyte biology during the last decade has radically altered our views on the pathophysiologic process of proteinuria, glomerular disease, and progressive kidney disease. In this review, we highlight some of these landmark findings, but focus on recent advances in the field and implications for translating this biology into therapy for podocyte diseases.
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Affiliation(s)
- J Ashley Jefferson
- Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA.
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Weil EJ, Lemley KV, Yee B, Lovato T, Richardson M, Myers BD, Nelson RG. Podocyte detachment in type 2 diabetic nephropathy. Am J Nephrol 2011; 33 Suppl 1:21-4. [PMID: 21659731 DOI: 10.1159/000327047] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Glomerular podocyte number declines and urinary excretion of podocytes increases as kidney disease progresses in persons with type 2 diabetes mellitus (T2DM). METHODS Using high-power electron microscopy, we quantified podocyte detachment in T2DM. RESULTS We evaluated 106 glomeruli (range 1-6 per subject) from 40 Pima Indian subjects with T2DM enrolled in a clinical trial. On high-power electron micrographs, 35% of the subjects had no evidence of podocyte detachment. Among the remaining subjects, the median percentage of basement membrane with podocyte detachment was 0.62% (interquartile range = 0.32-1.52%). CONCLUSION Podocyte detachment from the glomerular basement membrane has been described and measured in type 1 diabetes mellitus using a different method. We now document podocyte detachment microscopically and quantify it morphometrically in humans with T2DM. The findings offer quantitative histologic support to a potential mechanism for the functional impairment, and possibly the sclerosis of glomeruli, in diabetic glomerular injury.
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Affiliation(s)
- E Jennifer Weil
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, USA
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Abstract
The podocyte plays a key role both in maintenance of the glomerular filtration barrier and in glomerular structural integrity. Podocyte injury and loss contribute to proteinuria and progressive sclerosis. Inhibitors of mammalian target of rapamycin (mTOR) have variably decreased or caused proteinuria and sclerosis in human disease and experimental settings. In this issue of the JCI, two interesting studies of podocyte-specific manipulation of the mTOR system shed light on the complexity of this pathway in the podocyte.
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Affiliation(s)
- Agnes B Fogo
- Department of Pathology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
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Forbes MS, Thornhill BA, Chevalier RL. Proximal tubular injury and rapid formation of atubular glomeruli in mice with unilateral ureteral obstruction: a new look at an old model. Am J Physiol Renal Physiol 2011; 301:F110-7. [PMID: 21429968 DOI: 10.1152/ajprenal.00022.2011] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Unilateral ureteral obstruction (UUO), employed extensively as a model of progressive renal interstitial fibrosis, results in rapid parenchymal deterioration. Atubular glomeruli are formed in many renal disorders, but their identification has been limited by labor-intensive available techniques. The formation of atubular glomeruli was therefore investigated in adult male mice subjected to complete UUO under general anesthesia. In this species, the urinary pole of Bowman's capsule is normally lined by tall parietal epithelial cells similar to those of the proximal tubule, and both avidly bind Lotus tetragonolobus lectin. Following UUO, these cells became flattened, lost their affinity for Lotus lectin, and no longer generated superoxide (revealed by nitroblue tetrazolium infusion). Based on Lotus lectin staining, stereological measurements, and serial section analysis, over 80% of glomeruli underwent marked transformation after 14 days of UUO. The glomerulotubular junction became stenotic and atrophic due to cell death by apoptosis and autophagy, with concomitant remodeling of Bowman's capsule to form atubular glomeruli. In this degenerative process, transformed epithelial cells sealing the urinary pole expressed α-smooth muscle actin, vimentin, and nestin. Although atubular glomeruli remained perfused, renin immunostaining was markedly increased along afferent arterioles, and associated maculae densae disappeared. Numerous progressive kidney disorders, including diabetic nephropathy, are characterized by the formation of atubular glomeruli. The rapidity with which glomerulotubular junctions degenerate, coupled with Lotus lectin as a marker of glomerular integrity, points to new investigative uses for the model of murine UUO focusing on mechanisms of epithelial cell injury and remodeling in addition to fibrogenesis.
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Affiliation(s)
- Michael S Forbes
- Dept. of Pediatrics, University of Virginia, Box 800386, Charlottesville, VA 22908, USA
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Marshall CB, Krofft RD, Blonski MJ, Kowalewska J, Logar CM, Pippin JW, Kim F, Feil R, Alpers CE, Shankland SJ. Role of smooth muscle protein SM22α in glomerular epithelial cell injury. Am J Physiol Renal Physiol 2011; 300:F1026-42. [PMID: 21289056 DOI: 10.1152/ajprenal.00187.2010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Podocytes are considered terminally differentiated cells in the mature kidney under normal conditions. In the face of injury, podocytes may proceed along several possible pathways, including dedifferentiation and proliferation, persistent cell cycle arrest, hypertrophy, apoptosis, or necrosis. There is mounting evidence that transdifferentiation into a dysregulated phenotype may also be a potential cell fate. We have previously reported that the transcript of SM22α, an actin-binding protein considered one of the earliest markers of smooth muscle differentiation, is upregulated nearly 70-fold in glomeruli of rats with passive Heymann nephritis (PHN). In contrast, the SM22α transcript is absent in normal adult rat glomeruli. The purpose of this study was to define SM22α's expression during kidney development and its role in glomerular diseases characterized by podocyte injury and proteinuria. During glomerulogenesis and podocyte differentiation, SM22α was expressed in glomeruli. This expression disappeared with glomerular maturation. Along with SM22α induction in PHN, confirmed at both mRNA and protein levels, SM22α was also induced across a broad range of proteinuric diseases, including experimental animal models (puromycin aminonucleoside nephropathy, adriamycin nephropathy, passive nephrotoxic nephritis, and diet-induced obesity) and human diseases (collapsing glomerulopathy, diabetic nephropathy, classic focal segmental glomerulosclerosis, IgA nephropathy, minimal-change disease, membranous nephropathy, and membranoproliferative glomerulonephritis). Crescentic glomerulonephritis was induced in SM22α +/+ and SM22α -/- mice by intraperitoneal injection of sheep anti-rabbit glomeruli antibody 12.5 mg/20 g body wt × 2 doses (n = 12-15/group), with mice euthanized at 7 and 14 days. Compared with SM22α -/- mice, SM22α +/+ mice demonstrated worse disease by histopathological parameters. In addition, there was greater apoptosis (cleaved caspase-3 immunostaining), fewer podocytes (Wilms' tumor-1 immunostaining), and less proliferation (Ki-67 immunostaining) in diseased SM22α +/+ mice. Furthermore, there was decreased activation of Erk1/2 in diseased SM22α +/+ mice. We conclude that the de novo expression of SM22α in glomerular epithelial cells affects the course of crescentic glomerulonephritis.
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Affiliation(s)
- Caroline B Marshall
- Div. of Nephrology, Department of Medicine, Univ. of Washington, Seattle, WA 98195, USA.
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Cheval L, Pierrat F, Dossat C, Genete M, Imbert-Teboul M, Duong Van Huyen JP, Poulain J, Wincker P, Weissenbach J, Piquemal D, Doucet A. Atlas of gene expression in the mouse kidney: new features of glomerular parietal cells. Physiol Genomics 2010; 43:161-73. [PMID: 21081658 DOI: 10.1152/physiolgenomics.00093.2010] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To gain molecular insight into kidney function, we performed a high-resolution quantitative analysis of gene expression in glomeruli and nine different nephron segments dissected from mouse kidney using Serial Analysis of Gene Expression (SAGE). We also developed dedicated bioinformatics tools and databases to annotate mRNA tags as transcripts. Over 800,000 mRNA SAGE tags were sequenced corresponding to >20,000 different mRNA tags present at least twice in at least one library. Hierarchical clustering analysis of tags demonstrated similarities between the three anatomical subsegments of the proximal tubule, between the cortical and medullary segments of the thick ascending limb of Henle's loop, and between the three segments constituting the aldosterone-sensitive distal nephron segments, whereas the glomerulus and distal convoluted tubule clusterized independently. We also identified highly specific mRNA markers of each subgroup of nephron segments and of most nephron segments. Tag annotation also identified numbers of putative antisense mRNAs. This database constitutes a reference resource in which the quantitative expression of a given gene can be compared with that of other genes in the same nephron segment, or between different segments of the nephron. To illustrate possible applications of this database, we performed a deeper analysis of the glomerulus transcriptome that unexpectedly revealed expression of several ion and water carriers; within the glomerulus, they were found to be preferentially expressed in the parietal sheet. It also revealed the major role of the zinc finger transcription factor Wt1 in the specificity of gene expression in the glomerulus. Finally, functional annotation of glomerulus-specific transcripts suggested a high proliferation activity of glomerular cells. Immunolabeling for PCNA confirmed a high percentage of proliferating cells in the glomerulus parietal sheet.
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Affiliation(s)
- Lydie Cheval
- UPMC Univ Paris 06, Univ Paris Descartes and INSERM, UMRS 872, Centre de recherche des Cordeliers, Paris, France
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Abstract
Multiphoton excitation fluorescence microscopy is a powerful noninvasive imaging technique for the deep optical sectioning of living tissues. Its application in several intact tissues is a significant advance in our understanding of organ function, including renal pathophysiological mechanisms. The glomerulus, the filtering unit in the kidney, is one good example of a relatively inaccessible and complex structure, with cell types that are otherwise difficult to study at high resolution in their native environment. In this article, we address the application, advantages, and limitations of this imaging technology for the study of the glomerular filtration barrier and the controversy it recently generated regarding the glomerular filtration of macromolecules. More advanced and accurate multiphoton determinations of the glomerular sieving coefficient that are presented here dismiss previous claims on the filtration of nephrotic levels of albumin. The sieving coefficient of 70-kD dextran was found to be around 0.001. Using a model of focal segmental glomerulosclerosis, increased filtration barrier permeability is restricted only to areas of podocyte damage, consistent with the generally accepted role of podocytes and the glomerular origin of albuminuria. Time-lapse imaging provides new details and important in vivo confirmation of the dynamics of podocyte movement, shedding, replacement, and the role of the parietal epithelial cells and Bowman's capsule in the pathology of glomerulosclerosis.
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Affiliation(s)
- János Peti-Peterdi
- Department of Physiology and Biophysics, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA 90033, USA.
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