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Smith DW, Azadi A, Lee CJ, Gardiner BS. Spatial composition and turnover of the main molecules in the adult glomerular basement membrane. Tissue Barriers 2023; 11:2110798. [PMID: 35959954 PMCID: PMC10364650 DOI: 10.1080/21688370.2022.2110798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/31/2022] [Accepted: 08/03/2022] [Indexed: 10/15/2022] Open
Abstract
The glomerular basement membrane (GBM) is an important tissue structure in kidney function. It is the membrane through which filtrate and solutes must pass to reach the nephron tubules. This review focuses on the spatial location of the main extracellular matrix components of the GBM. It also attempts to explain this organization in terms of their synthesis, transport, and loss. The picture that emerges is that the collagen IV and laminin content of GBM are in a very slow dynamic disequilibrium, leading to GBM thickening with age, and in contrast, some heparan sulfate proteoglycans are in a dynamic equilibrium with a very rapid turnover (i.e. half-life measured in ~hours) and flow direction against the flow of filtrate. The highly rapid heparan sulfate turnover may serve several roles, including an unclogging mechanism for the GBM, compressive stiffness of the GBM fiber network, and/or enabling podocycte-endothelial crosstalk against the flow of filtrate.
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Affiliation(s)
- David W. Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Azin Azadi
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
| | - Chang-Joon Lee
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
| | - Bruce S. Gardiner
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
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2
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Martins ALMDS, Bernardes AB, Ferreira VA, Wanderley DC, Araújo SDA, do Carmo Neto JR, da Silva CA, Lira RCP, Araújo LS, Dos Reis MA, Machado JR. In situ assessment of Mindin as a biomarker of podocyte lesions in diabetic nephropathy. PLoS One 2023; 18:e0284789. [PMID: 37130106 PMCID: PMC10153717 DOI: 10.1371/journal.pone.0284789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 04/07/2023] [Indexed: 05/03/2023] Open
Abstract
Diabetic nephropathy (DN) is the leading cause of chronic kidney disease and end-stage renal failure worldwide. Several mechanisms are involved in the pathogenesis of this disease, which culminate in morphological changes such as podocyte injury. Despite the complex diagnosis and pathogenesis, limited attempts have been made to establish new biomarkers for DN. The higher concentration of Mindin protein in the urine of patients with type 2 diabetes mellitus suggests that it plays a role in DN. Therefore, this study investigated whether in situ protein expression of Mindin can be considered a potential DN biomarker. Fifty renal biopsies from patients diagnosed with DN, 57 with nondiabetic glomerular diseases, including 17 with focal segmental glomerulosclerosis (FSGS), 14 with minimal lesion disease (MLD) and 27 with immunoglobulin A nephropathy (IgAN), and 23 adult kidney samples from autopsies (control group) were evaluated for Mindin expression by immunohistochemistry. Podocyte density was inferred by Wilms' tumor 1 (WT1) immunostaining, while foot process effacement was assessed by transmission electron microscopy. Receiver operative characteristic (ROC) analysis was performed to determine the biomarker sensitivity/specificity. Low podocyte density and increased Mindin expression were observed in all cases of DN, regardless of their class. In the DN group, Mindin expression was significantly higher than that in the FSGS, MCD, IgAN and control groups. Higher Mindin expression was significantly positively correlated with foot process effacement only in class III DN cases. Furthermore, Mindin protein presented high specificity in the biopsies of patients with DN (p < 0.0001). Our data suggest that Mindin may play a role in DN pathogenesis and is a promising biomarker of podocyte lesions.
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Affiliation(s)
- Ana Luisa Monteiro Dos Santos Martins
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Alexia Borges Bernardes
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Verônica Aparecida Ferreira
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - David Campos Wanderley
- Institute of Nephropathology, Center for Electron Microscopy, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Stanley de Almeida Araújo
- Institute of Nephropathology, Center for Electron Microscopy, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - José Rodrigues do Carmo Neto
- Department of Bioscience and Technology, Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiania, Goiás, Brazil
| | - Crislaine Aparecida da Silva
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Régia Caroline Peixoto Lira
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Liliane Silvano Araújo
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Marlene Antônia Dos Reis
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
| | - Juliana Reis Machado
- Department of Pathology, Genetics and Evolution, Discipline of General Pathology, Institute of Biological and Natural Sciences of Federal University of Triângulo Mineiro, Uberaba, Minas Gerais, Brazil
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3
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Zeng L, Fung WWS, Chan GCK, Ng JKC, Chow KM, Szeto CC. Urinary and Kidney Podocalyxin and Podocin Levels in Diabetic Kidney Disease: A Kidney Biopsy Study. Kidney Med 2022; 5:100569. [PMID: 36654969 PMCID: PMC9841354 DOI: 10.1016/j.xkme.2022.100569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rationale & Objective Diabetic kidney diseases (DKDs) are the most common cause of dialysis-dependent kidney disease around the world. Previous studies have suggested that urinary level of podocyte-associated molecules may predict the prognosis of DKD. Study Design Observational cohort. Setting & Participants 118 consecutive patients with biopsy-proven DKD; 13 nondiabetic patients with hypertensive nephrosclerosis as controls. Predictors Urinary podocalyxin and podocin levels were obtained by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) and the corresponding intrarenal levels by western blotting. Outcomes Dialysis-free survival; kidney event-free survival; rate of kidney function decline in 12 months. Analytical Approach Correlation and time to event analysis. Results Urinary podocalyxin level was closely correlated with its messenger RNA (mRNA) level (r = 0.562, P < 0.001), but this did not predict the progression of DKD. Intrarenal podocalyxin level had only modest correlation with its urinary mRNA and ELISA levels, was an independent predictor of dialysis-free survival (adjusted HR, 1.85; 95% CI, 1.21-2.82; P = 0.005), and showed an insignificant trend of predicting kidney event-free survival (adjusted HR, 1.36; 95% CI, 0.94-1.95; P = 0.10). Urinary podocin level by ELISA had a modest correlation with the rate of kidney function decline (r = 0.238, P = 0.01) but did not predict dialysis-free survival. Limitations Small sample size; lack of serial measurement. Conclusions Intrarenal podocalyxin level, but not its urinary level, was an independent predictor of dialysis-free survival, whereas urinary podocin level by ELISA correlated with the rate of kidney function decline. Although intrarenal podocalyxin level has prognostic value, it may not be suitable for routine clinical use.
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Affiliation(s)
- Lingfeng Zeng
- Carol & Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Winston Wing-Shing Fung
- Carol & Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Gordon Chun-Kau Chan
- Carol & Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Jack Kit-Chung Ng
- Carol & Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Kai-Ming Chow
- Carol & Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China
| | - Cheuk-Chun Szeto
- Carol & Richard Yu Peritoneal Dialysis Research Centre, Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, China,Li Ka Shing Institute of Health Sciences (LiHS), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China,Address for Correspondence: Cheuk-Chun Szeto, MD, Department of Medicine & Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
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4
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Urinary podocyte markers in kidney diseases. Clin Chim Acta 2021; 523:315-324. [PMID: 34666027 DOI: 10.1016/j.cca.2021.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/17/2021] [Accepted: 10/13/2021] [Indexed: 01/19/2023]
Abstract
Podocytes play an important role in the maintenance of kidney function, and they are the primary focus of many kidney diseases. Podocyte injury results in the shedding of podocyte-derived cellular fragments and podocyte-specific molecular targets into the urine, which may serve as biomarkers of kidney diseases. Intact podocytes, either viable or dead, and podocyte-derived microvesicles could be quantified in the urine by various centrifugation, visualization and culture methods. Podocyte-specific protein targets from the nucleus, cytoplasm, slit-diaphragm, glomerular capillary basement membrane, and cytoskeleton, as well as their corresponding messenger RNA (mRNA), in the urine could be quantified by western blotting, ELISA, or quantitative polymerase chain reaction. Although some of these techniques may be expensive or labor-intensive at present, they may become widely available in the future because of the improvement in technology and automation. The application of urinary podocyte markers for the diagnosis and monitoring of various kidney diseases have been explored but the published data in this area are not sufficiently systematic and lack external validation. Further research should focus on standardizing, comparing, and automizing laboratory methods, as well as defining their added value to the routine clinical tests.
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5
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Podocalyxin in Normal Tissue and Epithelial Cancer. Cancers (Basel) 2021; 13:cancers13122863. [PMID: 34201212 PMCID: PMC8227556 DOI: 10.3390/cancers13122863] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 12/13/2022] Open
Abstract
Podocalyxin (PODXL), a glycosylated cell surface sialomucin of the CD34 family, is normally expressed in kidney podocytes, vascular endothelial cells, hematopoietic progenitors, mesothelium, as well as a subset of neurons. In the kidney, PODXL functions primarily as an antiadhesive molecule in podocyte epithelial cells, regulating adhesion and cell morphology, and playing an essential role in the development and function of the organ. Outside the kidney, PODXL plays subtle roles in tissue remodelling and development. Furthermore, many cancers, especially those that originated from the epithelium, have been reported to overexpress PODXL. Collective evidence suggests that PODXL overexpression is linked to poor prognosis, more aggressive tumour progression, unfavourable treatment outcomes, and possibly chemoresistance. This review summarises our current knowledge of PODXL in normal tissue function and epithelial cancer, with a particular focus on its underlying roles in cancer metastasis, likely involvement in chemoresistance, and potential use as a diagnostic and prognostic biomarker.
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Tamayo-Orbegozo E, Amo L, Díez-García J, Amutio E, Riñón M, Alonso M, Arana P, Maruri N, Larrucea S. Emerging Role of Podocalyxin in the Progression of Mature B-Cell Non-Hodgkin Lymphoma. Cancers (Basel) 2020; 12:cancers12020396. [PMID: 32046309 PMCID: PMC7072361 DOI: 10.3390/cancers12020396] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/03/2020] [Accepted: 02/06/2020] [Indexed: 02/06/2023] Open
Abstract
Mature B-cell non-Hodgkin lymphoma (B-NHL) constitutes a group of heterogeneous malignant lymphoproliferative diseases ranging from indolent to highly aggressive forms. Although the survival after chemo-immunotherapy treatment of mature B-NHL has increased over the last years, many patients relapse or remain refractory due to drug resistance, presenting an unfavorable prognosis. Hence, there is an urgent need to identify new prognostic markers and therapeutic targets. Podocalyxin (PODXL), a sialomucin overexpressed in a variety of tumor cell types and associated with their aggressiveness, has been implicated in multiple aspects of cancer progression, although its participation in hematological malignancies remains unexplored. New evidence points to a role for PODXL in mature B-NHL cell proliferation, survival, migration, drug resistance, and metabolic reprogramming, as well as enhanced levels of PODXL in mature B-NHL. Here, we review the current knowledge on the contribution of PODXL to tumorigenesis, highlighting and discussing its role in mature B-NHL progression.
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Affiliation(s)
- Estíbaliz Tamayo-Orbegozo
- Regulation of the Immune System Group, Biocruces Bizkaia Health Research Institute, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain; (E.T.-O.); (L.A.)
| | - Laura Amo
- Regulation of the Immune System Group, Biocruces Bizkaia Health Research Institute, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain; (E.T.-O.); (L.A.)
| | - Javier Díez-García
- Microscopy Facility, Biocruces Bizkaia Health Research Institute, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain;
| | - Elena Amutio
- Blood Cancer Group, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain;
| | - Marta Riñón
- Regulation of the Immune System Group, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain; (M.R.); (M.A.); (P.A.); (N.M.)
| | - Marta Alonso
- Regulation of the Immune System Group, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain; (M.R.); (M.A.); (P.A.); (N.M.)
| | - Paula Arana
- Regulation of the Immune System Group, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain; (M.R.); (M.A.); (P.A.); (N.M.)
| | - Natalia Maruri
- Regulation of the Immune System Group, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain; (M.R.); (M.A.); (P.A.); (N.M.)
| | - Susana Larrucea
- Regulation of the Immune System Group, Biocruces Bizkaia Health Research Institute, Hospital Universitario Cruces, Plaza de Cruces 12, 48903 Barakaldo, Bizkaia, Spain; (M.R.); (M.A.); (P.A.); (N.M.)
- Correspondence:
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7
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Sanchez-Niño MD, Perez-Gomez MV, Valiño-Rivas L, Torra R, Ortiz A. Podocyturia: why it may have added value in rare diseases. Clin Kidney J 2018; 12:49-52. [PMID: 30863545 PMCID: PMC6407136 DOI: 10.1093/ckj/sfy081] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 07/30/2018] [Indexed: 12/12/2022] Open
Abstract
Fabry disease is an inherited lysosomal disease in which defects in the GLA gene lead to α-galactosidase-A deficiency, and accumulation of glycosphingolipids, including lyso-Gb3, a podocyte stressor. Therapy is available as enzyme replacement therapy and, for some patients, the chaperone migalastat. A key decision is when to start therapy, given its costs and potential impact on some aspects of quality of life. The decision is especially difficult in otherwise asymptomatic patients. A delayed start of therapy may allow kidney injury to progress subclinically up to the development of irreversible lesions. Non-invasive tools to monitor subclinical kidney injury are needed. One such tool may be assessment of podocyturia. In this issue of CKJ, [Trimarchi H, Canzonieri R, Costales-Collaguazo C et al. Early decrease in the podocalyxin to synaptopodin ratio in urinary Fabry podocytes. Clin Kidney J 2019; doi.org/10.1093/ckj/sfy053] report on podocyturia assessment in Fabry nephropathy. Specifically, they report that podocalyxin may be lost from detached urinary podocytes.
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Affiliation(s)
- Maria Dolores Sanchez-Niño
- IIS-Fundacion Jimenez Diaz, School of Medicine, Universidad Autonoma de Madrid; Fundacion Renal Iñigo Alvarez de Toledo-IRSIN and REDINREN, Madrid, Spain
| | - Maria Vanessa Perez-Gomez
- IIS-Fundacion Jimenez Diaz, School of Medicine, Universidad Autonoma de Madrid; Fundacion Renal Iñigo Alvarez de Toledo-IRSIN and REDINREN, Madrid, Spain
| | - Lara Valiño-Rivas
- IIS-Fundacion Jimenez Diaz, School of Medicine, Universidad Autonoma de Madrid; Fundacion Renal Iñigo Alvarez de Toledo-IRSIN and REDINREN, Madrid, Spain
| | - Roser Torra
- Inherited Renal Disorders, Nephrology Department, Fundació Puigvert, REDINREN, IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Alberto Ortiz
- IIS-Fundacion Jimenez Diaz, School of Medicine, Universidad Autonoma de Madrid; Fundacion Renal Iñigo Alvarez de Toledo-IRSIN and REDINREN, Madrid, Spain
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8
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Schroeter CB, Koehler S, Kann M, Schermer B, Benzing T, Brinkkoetter PT, Rinschen MM. Protein half-life determines expression of proteostatic networks in podocyte differentiation. FASEB J 2018; 32:4696-4713. [PMID: 29694247 DOI: 10.1096/fj.201701307r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Podocytes are highly specialized, epithelial, postmitotic cells, which maintain the renal filtration barrier. When adapting to considerable metabolic and mechanical stress, podocytes need to accurately maintain their proteome. Immortalized podocyte cell lines are a widely used model for studying podocyte biology in health and disease in vitro. In this study, we performed a comprehensive proteomic analysis of the cultured human podocyte proteome in both proliferative and differentiated conditions at a depth of >7000 proteins. Similar to mouse podocytes, human podocyte differentiation involved a shift in proteostasis: undifferentiated podocytes have high expression of proteasomal proteins, whereas differentiated podocytes have high expression of lysosomal proteins. Additional analyses with pulsed stable-isotope labeling by amino acids in cell culture and protein degradation assays determined protein dynamics and half-lives. These studies unraveled a globally increased stability of proteins in differentiated podocytes. Mitochondrial, cytoskeletal, and membrane proteins were stabilized, particularly in differentiated podocytes. Importantly, protein half-lives strongly contributed to protein abundance in each state. These data suggest that regulation of protein turnover of particular cellular functions determines podocyte differentiation, a paradigm involving mitophagy and, potentially, of importance in conditions of increased podocyte stress and damage.-Schroeter, C. B., Koehler, S., Kann, M., Schermer, B., Benzing, T., Brinkkoetter, P. T., Rinschen, M. M. Protein half-life determines expression of proteostatic networks in podocyte differentiation.
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Affiliation(s)
- Christina B Schroeter
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Sybille Koehler
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Martin Kann
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (SybaCol), Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (SybaCol), Cologne, Germany
| | - Paul T Brinkkoetter
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department II of Internal Medicine, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Systems Biology of Ageing Cologne (SybaCol), Cologne, Germany
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9
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Sheng WS, Xu HL, Zheng L, Zhuang YD, Jiao LZ, Zhou JF, ZhuGe DL, Chi TT, Zhao YZ, Lan L. Intrarenal delivery of bFGF-loaded liposome under guiding of ultrasound-targeted microbubble destruction prevent diabetic nephropathy through inhibition of inflammation. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2018; 46:373-385. [PMID: 29653493 DOI: 10.1080/21691401.2018.1457538] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Wen-Shuang Sheng
- Department of Ultrasound, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - He-Lin Xu
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Lei Zheng
- Department of Ultrasound, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yuan-Di Zhuang
- Department of Ultrasound, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Li-Zhuo Jiao
- Department of Ultrasound, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jia-Feng Zhou
- Department of Ultrasound, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - De-Li ZhuGe
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Ting-Ting Chi
- Department of Ultrasound, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Ying-Zheng Zhao
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Li Lan
- Department of Ultrasound, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
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10
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Podocalyxin promotes proliferation and survival in mature B-cell non-Hodgkin lymphoma cells. Oncotarget 2017; 8:99722-99739. [PMID: 29245936 PMCID: PMC5725127 DOI: 10.18632/oncotarget.21283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 08/17/2017] [Indexed: 12/15/2022] Open
Abstract
Podocalyxin (PCLP1) is a CD34-related sialomucin expressed by some normal cells and a variety of malignant tumors, including leukemia, and associated with the most aggressive cancers and poor clinical outcome. PCLP1 increases breast tumor growth, migration and invasion; however, its role in hematologic malignancies still remains undetermined. The purpose of this study was to investigate the expression and function of PCLP1 in mature B-cell lymphoma cells. We found that overexpression of PCLP1 significantly increases proliferation, cell-to-cell interaction, clonogenicity, and migration of B-cell lymphoma cells. Furthermore, PCLP1 overexpression results in higher resistance to death induced by dexamethasone, reactive oxygen species and type II anti-CD20 monoclonal antibody obinutuzumab. Strikingly, enforced expression of PCLP1 enhances lipid droplet formation as well as pentose phosphate pathway and glutamine dependence, indicative of metabolic reprogramming necessary to support the abnormal proliferation rate of tumor cells. Flow cytometry analysis revealed augmented levels of PCLP1 in malignant cells from some patients with mature B-cell lymphoma compared to their normal B-cell counterparts. In summary, our results demonstrate that PCLP1 contributes to proliferation and survival of mature B-cell lymphoma cells, suggesting that PCLP1 may promote lymphomagenesis and represents a therapeutic target for the treatment of B-cell lymphomas.
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Ren X, Liu G, Wang Y, Zhang W, Xue F, Li R, Yu W. Influence of Dipeptidyl Peptidase-IV Inhibitor Sitagliptin on Extracellular Signal-Regulated Kinases 1/2 Signaling in Rats with Diabetic Nephropathy. Pharmacology 2017; 100:1-13. [PMID: 28329747 DOI: 10.1159/000455874] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/05/2017] [Indexed: 12/31/2022]
Abstract
The protective effects of sitagliptin on the kidneys of rats with diabetic nephropathy (DN) and its influence on extracellular signal-regulated kinases 1/2 (ERK1/2) signaling were investigated. Male Wistar rats (n = 40) were randomly assigned to normal control, DN, low-dose sitagliptin intervention (ST1), or high-dose sitagliptin intervention (ST2) groups. Animals were euthanized after a 16-week treatment, and blood glucose (BG), glycosylated hemoglobin (HbA1c), urinary albumin excretion rate (AER), serum creatinine (Scr), creatinine clearance rate (Ccr), active glucagon-like peptide-1 (GLP-1) levels, kidney hypertrophy index, and renal pathohistology were determined. Immunohistochemical methods and real-time polymerase chain reaction (PCR) were used to detect protein and mRNA expression of podocalyxin, ERK1/2, GLP-1 receptor (GLP-1R) and transforming growth factor-β (TGF-β). After 16 weeks, BG, AER, Scr, HbA1c and the kidney hypertrophy index were all significantly decreased (p < 0.05) in ST1 and ST2 groups, while Ccr and active GLP-1 levels were increased (p < 0.05), with changes more pronounced in ST2 (p < 0.05). Glomerular pathological lesions were also improved following sitagliptin treatment, especially in ST2. Immunohistochemical and real-time PCR revealed that protein and mRNA expression levels of podocalyxin and GLP-1R were increased significantly in ST1 and ST2, while expression of ERK1/2 and TGF-β was decreased (p < 0.05). Sitagliptin therefore delayed DN progression, possibly via the inhibition of ERK1/2 signaling and promotion of the interaction between GLP-1 and the GLP-1R.
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Affiliation(s)
- Xiaojun Ren
- Department of Nephrology, Shanxi Dayi Hospital (Shanxi Academy of Medical Sciences), Taiyuan, China
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12
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Katsoulieris EN, Drossopoulou GI, Kotsopoulou ES, Vlahakos DV, Lianos EA, Tsilibary EC. High Glucose Impairs Insulin Signaling in the Glomerulus: An In Vitro and Ex Vivo Approach. PLoS One 2016; 11:e0158873. [PMID: 27434075 PMCID: PMC4951020 DOI: 10.1371/journal.pone.0158873] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/23/2016] [Indexed: 01/14/2023] Open
Abstract
Objective Chronic hyperglycaemia, as seen in type II diabetes, results in both morphological and functional impairments of podocytes in the kidney. We investigated the effects of high glucose (HG) on the insulin signaling pathway, focusing on cell survival and apoptotic markers, in immortalized human glomerular cells (HGEC; podocytes) and isolated glomeruli from healthy rats. Methods and Findings HGEC and isolated glomeruli were cultured for various time intervals under HG concentrations in the presence or absence of insulin. Our findings indicated that exposure of HGEC to HG led to downregulation of all insulin signaling markers tested (IR, p-IR, IRS-1, p-Akt, p-Fox01,03), as well as to increased sensitivity to apoptosis (as seen by increased PARP cleavage, Casp3 activation and DNA fragmentation). Short insulin pulse caused upregulation of insulin signaling markers (IR, p-IR, p-Akt, p-Fox01,03) in a greater extent in normoglycaemic cells compared to hyperglycaemic cells and for the case of p-Akt, in a PI3K-dependent manner. IRS-1 phosphorylation of HG-treated podocytes was negatively regulated, favoring serine versus tyrosine residues. Prolonged insulin treatment caused a significant decrease of IR levels, while alterations in glucose concentrations for various time intervals demonstrated changes of IR, p-IR and p-Akt levels, suggesting that the IR signaling pathway is regulated by glucose levels. Finally, HG exerted similar effects in isolated glomeruli. Conclusions These results suggest that HG compromises the insulin signaling pathway in the glomerulus, promoting a proapoptotic environment, with a possible critical step for this malfunction lying at the level of IRS-1 phosphorylation; thus we herein demonstrate glomerular insulin signaling as another target for investigation for the prevention and/ or treatment of diabetic nephropathy.
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Affiliation(s)
- Elias N. Katsoulieris
- Institute of Biosciences and Applications, National Center for Scientific Research ‘Demokritos’, Athens, Greece
| | - Garyfalia I. Drossopoulou
- Institute of Biosciences and Applications, National Center for Scientific Research ‘Demokritos’, Athens, Greece
- * E-mail: (GID); (ECT)
| | - Eleni S. Kotsopoulou
- Institute of Biosciences and Applications, National Center for Scientific Research ‘Demokritos’, Athens, Greece
| | - Dimitrios V. Vlahakos
- 2nd Department of Propaedeutic Medicine, Attikon University Hospital, Athens, Greece
| | - Elias A. Lianos
- Department of Pathology, National and Kapodistrian University of Athens, Medical School, Athens, Greece
| | - Effie C. Tsilibary
- Institute of Biosciences and Applications, National Center for Scientific Research ‘Demokritos’, Athens, Greece
- * E-mail: (GID); (ECT)
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Blood pressure and glucose independent renoprotective effects of dipeptidyl peptidase-4 inhibition in a mouse model of type-2 diabetic nephropathy. J Hypertens 2016; 32:2211-23; discussion 2223. [PMID: 25215436 DOI: 10.1097/hjh.0000000000000328] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Despite the beneficial effects of type 4 dipeptidyl peptidase (DPP-4) inhibitors on glucose levels, its effects on diabetic nephropathy remain unclear. METHOD This study examined the long-term renoprotective effects of DPP-4 inhibitor linagliptin in db/db mice, a model of type 2 diabetes. Results were compared with the known beneficial effects of renin-angiotensin system blockade by enalapril. Ten-week-old male diabetic db/db mice were treated for 3 months with either vehicle (n = 10), 3 mg linagliptin/kg per day (n = 8), or 20 mg enalapril/kg per day (n = 10). Heterozygous db/m mice treated with vehicle served as healthy controls (n = 8). RESULTS Neither linagliptin nor enalapril had significant effects on the parameters of glucose metabolism or blood pressure in diabetic db/db mice. However, linagliptin treatment reduced albuminuria and attenuated kidney injury. In addition, expression of podocyte marker podocalyxin was normalized. We also analysed DPP-4 expression by immunofluorescence in human kidney biopsies and detected upregulation of DPP-4 in the glomeruli of patients with diabetic nephropathy, suggesting that our findings might be of relevance for human kidney disease as well. CONCLUSION Treatment with DPP-4 inhibitor linagliptin delays the progression of diabetic nephropathy damage in a glucose-independent and blood-pressure-independent manner. The observed effects may be because of the attenuation of podocyte injury and inhibition of myofibroblast transformation.
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Sawada K, Toyoda M, Kaneyama N, Shiraiwa S, Moriya H, Miyatake H, Tanaka E, Yamamoto N, Miyauchi M, Kimura M, Wada T, Fukagawa M. Upregulation of α3β1-Integrin in Podocytes in Early-Stage Diabetic Nephropathy. J Diabetes Res 2016; 2016:9265074. [PMID: 27340677 PMCID: PMC4908236 DOI: 10.1155/2016/9265074] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/05/2016] [Indexed: 01/15/2023] Open
Abstract
Background. Podocyte injury plays an important role in the onset and progression of diabetic nephropathy (DN). Downregulation of α3β1-integrin expression in podocytes is thought to be associated with podocyte detachment from the glomerular basement membrane, although the mechanisms remain obscure. To determine the mechanism of podocyte detachment, we analyzed the expression levels of α3β1-integrin in podocytes in early and advanced stages of DN. Methods. Surgical specimens from DN patients were examined by in situ hybridization, and the expression levels of α3- and β1-integrin subunits in glomeruli of early (n = 6) and advanced (n = 8) stages were compared with those of normal glomeruli (n = 5). Heat-sensitive mouse podocytes (HSMP) were cultured with TGF-β1 to reproduce the microenvironment of glomeruli of DN, and the expression levels of integrin subunits and the properties of migration and attachment were examined. Results. Podocytes of early-stage DN showed upregulation of α3- and β1-integrin expression while those of advanced stage showed downregulation. Real-time PCR indicated a tendency for upregulation of α3- and β1-integrin in HSMP cultured with TGF-β1. TGF-β1-stimulated HSMP also showed enhanced in vitro migration and attachment on collagen substrate. Conclusions. The results suggested that podocyte detachment during early stage of DN is mediated through upregulation of α3β1-integrin.
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Affiliation(s)
- Kaichiro Sawada
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Masao Toyoda
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
- *Masao Toyoda:
| | - Noriko Kaneyama
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Sawako Shiraiwa
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Hitomi Moriya
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Han Miyatake
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Eitaro Tanaka
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Naoyuki Yamamoto
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Masaaki Miyauchi
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Moritsugu Kimura
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Takehiko Wada
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology and Metabolism, Department of Medicine, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan
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Guo F, Zhang Y, Wang Q, Ren L, Zhou Y, Ma X, Wu L, Qin G. Effects of FoxO1 on podocyte injury in diabetic rats. Biochem Biophys Res Commun 2015; 466:260-6. [PMID: 26361145 DOI: 10.1016/j.bbrc.2015.09.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 08/03/2015] [Accepted: 09/05/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE This study was designed to investigate the protective effect of forkhead transcription factor O1 (FoxO1) on podocyte injury in rats with diabetic nephropathy. METHODS Streptozotocin-induced diabetic rats were served as DM group, while DM rats transfected with blank lentiviral vectors (LV-pSC-GFP) or lentiviral vectors carrying constitutively active FoxO1 (LV-CA-FoxO1) were served as LV-NC group or LV-CA group, respectively. The control group (NG) consisted of uninduced rats that received an injection of diluent buffer. At 2, 4, and 8 weeks after transfection, the levels of urine albumin, blood glucose, blood urea nitrogen, serum creatinine and urine podocalyxin were measured. Real-time PCR and western blotting were performed to measure mRNA and protein levels of FoxO1, podocalyxin, nephrin, and desmin in renal cortex. In addition, light and electron microscopy were used to detect structural changes in the glomerulus and podocytes. RESULTS Compared with the rats in LV-NC and DM groups, LV-CA rats showed a significant increase in FoxO1 mRNA and protein levels and a distinct decrease in urine albumin, blood urea nitrogen, and serum creatinine (except at the two-week time point) levels (p < 0.05). Podocalyxin and nephrin mRNA and protein levels increased (p < 0.05), whereas desmin mRNA and protein levels decreased (p < 0.05). Pathological changes in glomerulus were also ameliorated in LV-CA group. CONCLUSIONS Upregulating expression of FoxO1 by transduction with recombinant lentivirus ameliorates podocyte injury in diabetic rats.
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Affiliation(s)
- Feng Guo
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Yuanyuan Zhang
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Qingzhu Wang
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Lei Ren
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Yingni Zhou
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Xiaojun Ma
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Lina Wu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China; Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Guijun Qin
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China.
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Lin CW, Sun MS, Wu HC. Podocalyxin-like 1 is associated with tumor aggressiveness and metastatic gene expression in human oral squamous cell carcinoma. Int J Oncol 2014; 45:710-8. [PMID: 24821609 DOI: 10.3892/ijo.2014.2427] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/07/2014] [Indexed: 11/05/2022] Open
Abstract
Metastasis-mediated death remains a major challenge in cancer treatment due to the lack of identifiable biomarkers for early diagnosis. Identifying tumor-specific biomarkers is critical for the development of diagnostic and therapeutic tools. In the present study, we found that podocalyxin-like 1 (PODXL), a cell surface glycoprotein, was overexpressed in cancer tissues and was upregulated in lymph node metastatic tumor cells. The expression of PODXL was associated with the migratory ability of human oral squamous cell carcinoma (OSCC). Knockdown of PODXL by small hairpin RNA in the SAS OSCC cell line reduced tumor migration and invasion, and inhibited cell proliferation and colony formation. Suppression of PODXL resulted in downregulation of focal adhesion kinase (FAK) and paxillin phosphorylation. PODXL silencing inhibited filopodia formation, and suppressed F-actin and cortactin colocalization. In addition, PODXL expression was associated with the DNA methylation status, and treatment with the DNA methyltransferase inhibitor 5-aza-deoxycytidine increased the PODXL transcriptional level. Moreover, DNA microarray analysis data revealed that suppression of PODXL significantly affected subsets of genes associated with extracellular matrix organization, the epithelial-mesenchymal transition, and the expression of metastasis-related cytokines. Collectively, these data showed that the overexpression of PODXL may be associated with tumor aggressiveness and that PODXL could be a diagnostic biomarker for metastatic OSCC.
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Affiliation(s)
- Cheng-Wei Lin
- Department of Biochemistry, School of Medicine, Taipei Medical University, Taipei 115, Taiwan, R.O.C
| | - Min-Siou Sun
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan, R.O.C
| | - Han-Chung Wu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan, R.O.C
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Abstract
Diabetes mellitus contributes greatly to morbidity, mortality, and overall health care costs. In major part, these outcomes derive from the high incidence of progressive kidney dysfunction in patients with diabetes making diabetic nephropathy a leading cause of end-stage renal disease. A better understanding of the molecular mechanism involved and of the early dysfunctions observed in the diabetic kidney may permit the development of new strategies to prevent diabetic nephropathy. Here we review the pathophysiological changes that occur in the kidney in response to hyperglycemia, including the cellular responses to high glucose and the responses in vascular, glomerular, podocyte, and tubular function. The molecular basis, characteristics, and consequences of the unique growth phenotypes observed in the diabetic kidney, including glomerular structures and tubular segments, are outlined. We delineate mechanisms of early diabetic glomerular hyperfiltration including primary vascular events as well as the primary role of tubular growth, hyperreabsorption, and tubuloglomerular communication as part of a "tubulocentric" concept of early diabetic kidney function. The latter also explains the "salt paradox" of the early diabetic kidney, that is, a unique and inverse relationship between glomerular filtration rate and dietary salt intake. The mechanisms and consequences of the intrarenal activation of the renin-angiotensin system and of diabetes-induced tubular glycogen accumulation are discussed. Moreover, we aim to link the changes that occur early in the diabetic kidney including the growth phenotype, oxidative stress, hypoxia, and formation of advanced glycation end products to mechanisms involved in progressive kidney disease.
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Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California San Diego & VA San Diego Healthcare System, San Diego, California, USA.
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18
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Tsotakos NE, Sagnou M, Kotsopoulou ES, Tsilibary EC, Drossopoulou GI. Glucose-induced gradual phenotypic modulation of cultured human glomerular epithelial cells may be independent of Wilms' tumor 1 (WT1). BMC Cell Biol 2013; 14:28. [PMID: 23768159 PMCID: PMC3686613 DOI: 10.1186/1471-2121-14-28] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 05/23/2013] [Indexed: 12/24/2022] Open
Abstract
Background Renal podocytes form the main filtration barrier possessing a unique phenotype maintained by proteins including podocalyxin and nephrin, the expression of which is suppressed in pathological conditions. We used an in vitro model of human glomerular epithelial cells (HGEC) to investigate the role of high glucose in dysregulating the podocytic epithelial phenotype and determined the time needed for this change to occur. Results In our in vitro podocyte system changes indicating podocyte dedifferentiation in the prolonged presence of high glucose included loss of podocalyxin, nephrin and CD10/CALLA concomitant with upregulation of mesenchymal vimentin. Our study demonstrates for the first time that podocyte-specific markers undergo changes of expression at different time intervals, since glucose-mediated podocalyxin downregulation is a progressive process that precedes downregulation of nephrin expression. Finally we demonstrate that high glucose permanently impaired WT1 binding to the podocalyxin gene promoter region but did not affect WT1 binding on the nephrin gene promoter region. Conclusion The presence of high glucose induced a phenotypic conversion of podocytes resembling partial dedifferentiation. Our study demonstrates that dysregulation of the normal podocytic phenotype is an event differentially affecting the expression of function-specific podocytic markers, exhibiting downregulation of the epithelial marker CD10/CALLA and PC first, followed by stably downregulated nephrin. Furthermore, it is herein suggested that WT1 may not be directly involved with upregulation of previously reduced PC and nephrin expression.
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Affiliation(s)
- Nikolaos E Tsotakos
- Institute of Biosciences and Applications, National Centre for Scientific Research Demokritos, Athens, Greece
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19
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Li K, Wang J, Yin X, Zhai X, Li Z. Alteration of podocyte protein expression and localization in the early stage of various hemodynamic conditions. Int J Mol Sci 2013; 14:5998-6011. [PMID: 23502465 PMCID: PMC3634401 DOI: 10.3390/ijms14035998] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/03/2013] [Accepted: 03/05/2013] [Indexed: 02/04/2023] Open
Abstract
Given that podocalyxin (PCX) and nestin play important roles in podocyte morphogenesis and the maintenance of structural integrity, we examined whether the expression and localization of these two podocyte proteins were influenced in the early stage of various hemodynamic conditions. Mice kidney tissues were prepared by in vivo cryotechnique (IVCT). The distribution of glomeruli and podocyte proteins was visualized with DAB staining, confocal laser scanning microscopy and immunoelectron microscopy. The mRNA levels were examined by real-time quantitative PCR. The results showed the following: Under the normal condition, PCX stained intensely along glomerular epithelial cells, whereas nestin was clearly staining in the endothelial cells and appeared only weakly in the podocytes. Under the acute hypertensive and cardiac arrest conditions, PCX and nestin staining was not clear, with a disarranged distribution, but the colocalization of PCX and nestin was apparent under this condition. In addition, under the acute hypertensive and cardiac arrest conditions, the mRNA levels of PCX and nestin were significantly decreased. Collectively, the abnormal redistribution and decreased mRNA expressions of PCX and nestin are important molecular events at the early stage of podocyte injury during hemodynamic disorders. IVCT may have more advantages for morphological analysis when researching renal diseases.
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Affiliation(s)
- Kai Li
- Department of Surgical Oncology, First Affiliated Hospital of China Medical University, Shenyang 110001, China; E-Mail:
| | - Juan Wang
- Department of Nephrology, First Affiliated Hospital of China Medical University, Shenyang 110001, China; E-Mails: (J.W.); (X.Y.)
| | - Xiaohui Yin
- Department of Nephrology, First Affiliated Hospital of China Medical University, Shenyang 110001, China; E-Mails: (J.W.); (X.Y.)
| | - Xiaoyue Zhai
- Department of Histology and Embryology, Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, China; E-Mail:
| | - Zilong Li
- Department of Nephrology, First Affiliated Hospital of China Medical University, Shenyang 110001, China; E-Mails: (J.W.); (X.Y.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +86-24-8328-2733
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20
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Verouti SN, Tsilibary EC, Fragopoulou E, Iatrou C, Demopoulos CA, Charonis AS, Charonis SA, Drossopoulou GI. Vitamin D receptor activators upregulate and rescue podocalyxin expression in high glucose-treated human podocytes. Nephron Clin Pract 2013; 122:36-50. [PMID: 23548800 DOI: 10.1159/000346562] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 12/11/2012] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Vitamin D is beneficial in human and experimental chronic kidney disease, the leading cause of which is diabetic nephropathy. Vitamin D through its receptor, VDR, provides renal protection in diabetic nephropathy, but limited data exist about its effect on podocytes. Renal podocytes form the main filtration barrier possessing a unique phenotype maintained by proteins including podocalyxin and nephrin, the expression of which is suppressed in pathological conditions. METHODS We used immortalized human podocytes (human glomerular epithelial cells, HGEC) to assess podocalyxin and nephrin expression after treatment with 1,25-dihydroxyvitamin D3 (calcitriol) and its analogue paricalcitol. The involvement of VDR was investigated by silencing with hVDR-siRNA and ChIP analysis. RESULTS HGEC exhibit high glucose-mediated downregulation of podocalyxin and nephrin, loss of which has been linked with loss of the permselective renal barrier and proteinuria. Calcitriol and paricalcitol reversed high glucose-induced decrease of nephrin and significantly enhanced podocalyxin expression in podocytes cultured in high glucose. HGEC express VDR and retinoid X receptor (RXR). In the presence of calcitriol and paricalcitol, VDR expression was upregulated and VDR colocalized with RXR in the nucleus. VDR knockdown abolished the protective action of calcitriol and paricalcitol on podocalyxin expression indicating that podocalyxin activation of expression is partly mediated by VDR. Furthermore, VDR specifically regulates podocalyxin expression by bounding to a site upstream of the podocalyxin promoter. CONCLUSION Vitamin D analogues maintain and, furthermore, re-activate the expression of specialized components of podocytes including podocalyxin, hence they provide protection against loss of the permselective renal barrier, with molecular mechanisms elucidated herein.
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Affiliation(s)
- S N Verouti
- Faculty of Chemistry, National and Kapodistrian University of Athens, Panepistimioupolis, Athens, Greece
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21
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Control of cell adhesion and migration by podocalyxin. Implication of Rac1 and Cdc42. Biochem Biophys Res Commun 2013; 432:302-7. [PMID: 23396057 DOI: 10.1016/j.bbrc.2013.01.112] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 01/30/2013] [Indexed: 11/22/2022]
Abstract
Podocalyxin (PODXL) is a type I membrane sialomucin, originally described in the epithelial cells (podocytes) of kidney glomeruli. PODXL is also found in extra-renal tissues and in certain aggressive tumors, but its precise pathophysiological role is unknown. Expression of PODXL in CHO cells enhances their adhesive, migratory and cell-cell interactive properties in a selectin and integrin-dependent manner. We aimed at defining the PODXL domains responsible for those cell responses. For this purpose we have analyzed the cell adhesion/migration responses to deletion mutants of human PODXL, and the correlation with the activities of Rac1 and Cdc42 GTPases. The results obtained indicate that integrity of the PODXL ectodomain is essential for enhancing cell adhesion but not migration, while the integrity of the cytoplasmic domain is required for both adhesion and migration. Deletion of the carboxy-terminal DTHL domain (PODXL-ΔDTHL) limited only cell adhesion. The activities of Rac1 and Cdc42 GTPases parallel the PODXL-induced variations in cell adhesion and migration. Moreover, silencing the rac1 gene virtually abolished the effect of PODXL in enhancing cell adhesion.
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22
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Song B, Smink AM, Jones CV, Callaghan JM, Firth SD, Bernard CA, Laslett AL, Kerr PG, Ricardo SD. The directed differentiation of human iPS cells into kidney podocytes. PLoS One 2012; 7:e46453. [PMID: 23029522 PMCID: PMC3460883 DOI: 10.1371/journal.pone.0046453] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 08/30/2012] [Indexed: 12/11/2022] Open
Abstract
The loss of glomerular podocytes is a key event in the progression of chronic kidney disease resulting in proteinuria and declining function. Podocytes are slow cycling cells that are considered terminally differentiated. Here we provide the first report of the directed differentiation of induced pluripotent stem (iPS) cells to generate kidney cells with podocyte features. The iPS-derived podocytes share a morphological phenotype analogous with cultured human podocytes. Following 10 days of directed differentiation, iPS podocytes had an up-regulated expression of mRNA and protein localization for podocyte markers including synaptopodin, nephrin and Wilm’s tumour protein (WT1), combined with a down-regulation of the stem cell marker OCT3/4. In contrast to human podocytes that become quiescent in culture, iPS-derived cells maintain a proliferative capacity suggestive of a more immature phenotype. The transduction of iPS podocytes with fluorescent labeled-talin that were immunostained with podocin showed a cytoplasmic contractile response to angiotensin II (AII). A permeability assay provided functional evidence of albumin uptake in the cytoplasm of iPS podocytes comparable to human podocytes. Moreover, labeled iPS-derived podocytes were found to integrate into reaggregated metanephric kidney explants where they incorporated into developing glomeruli and co-expressed WT1. This study establishes the differentiation of iPS cells to kidney podocytes that will be useful for screening new treatments, understanding podocyte pathogenesis, and offering possibilities for regenerative medicine.
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Affiliation(s)
- Bi Song
- Monash Immunology and Stem Cell Laboratories (MISCL), Monash University, Clayton, Victoria, Australia
| | - Alexandra M. Smink
- Monash Immunology and Stem Cell Laboratories (MISCL), Monash University, Clayton, Victoria, Australia
| | - Christina V. Jones
- Monash Immunology and Stem Cell Laboratories (MISCL), Monash University, Clayton, Victoria, Australia
| | - Judy M. Callaghan
- Monash Micro Imaging, Monash University, Clayton, Victoria, Australia
| | - Stephen D. Firth
- Monash Micro Imaging, Monash University, Clayton, Victoria, Australia
| | - Claude A. Bernard
- Monash Immunology and Stem Cell Laboratories (MISCL), Monash University, Clayton, Victoria, Australia
| | - Andrew L. Laslett
- CSIRO Materials Science and Engineering, Clayton, Victoria, Australia
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Peter G. Kerr
- Department of Medicine, Monash University, Monash Medical Centre, Clayton, Victoria, Australia
| | - Sharon D. Ricardo
- Monash Immunology and Stem Cell Laboratories (MISCL), Monash University, Clayton, Victoria, Australia
- * E-mail:
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Rigothier C, Auguste P, Welsh GI, Lepreux S, Deminière C, Mathieson PW, Saleem MA, Ripoche J, Combe C. IQGAP1 interacts with components of the slit diaphragm complex in podocytes and is involved in podocyte migration and permeability in vitro. PLoS One 2012; 7:e37695. [PMID: 22662192 PMCID: PMC3360763 DOI: 10.1371/journal.pone.0037695] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 04/24/2012] [Indexed: 12/18/2022] Open
Abstract
IQGAP1 is a scaffold protein that interacts with proteins of the cytoskeleton and the intercellular adhesion complex. In podocytes, IQGAP1 is associated with nephrin in the glomerular slit diaphragm (SD) complex, but its role remains ill-defined. In this work, we investigated the interaction of IQGAP1 with the cytoskeleton and SD proteins in podocytes in culture, and its role in podocyte migration and permeability. Expression, localization, and interactions between IQGAP1 and SD or cytoskeletal proteins were determined in cultured human podocytes by Western blot (WB), immunocytolocalization (IC), immunoprecipitation (IP), and In situ Proximity Ligation assay (IsPL). Involvement of IQGAP1 in migration and permeability was also assessed. IQGAP1 expression in normal kidney biopsies was studied by immunohistochemistry. IQGAP1 expression by podocytes increased during their in vitro differentiation. IC, IP, and IsPL experiments showed colocalizations and/or interactions between IQGAP1 and SD proteins (nephrin, MAGI-1, CD2AP, NCK 1/2, podocin), podocalyxin, and cytoskeletal proteins (α-actinin-4). IQGAP1 silencing decreased podocyte migration and increased the permeability of a podocyte layer. Immunohistochemistry on normal human kidney confirmed IQGAP1 expression in podocytes and distal tubular epithelial cells and also showed an expression in glomerular parietal epithelial cells. In summary, our results suggest that IQGAP1, through its interaction with components of SD and cytoskeletal proteins, is involved in podocyte barrier properties.
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24
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Hartleben B, Widmeier E, Wanner N, Schmidts M, Kim ST, Schneider L, Mayer B, Kerjaschki D, Miner JH, Walz G, Huber TB. Role of the polarity protein Scribble for podocyte differentiation and maintenance. PLoS One 2012; 7:e36705. [PMID: 22586490 PMCID: PMC3346764 DOI: 10.1371/journal.pone.0036705] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 04/05/2012] [Indexed: 11/19/2022] Open
Abstract
The kidney filter represents a unique assembly of podocyte epithelial cells that tightly enwrap the glomerular capillaries with their complex foot process network. While deficiency of the polarity proteins Crumbs and aPKC result in impaired podocyte foot process architecture, the function of basolateral polarity proteins for podocyte differentiation and maintenance remained unclear. Here we report, that Scribble is expressed in developing podocytes, where it translocates from the lateral aspects of immature podocytes to the basal cell membrane and foot processes of mature podocytes. Immunogold electron microscopy reveals membrane associated localisation of Scribble predominantly at the basolateral site of foot processes. To further study the role of Scribble for podocyte differentiation Scribble(flox/flox) mice were generated by introducing loxP-sites into the Scribble introns 1 and 8 and these mice were crossed to NPHS2.Cre mice and Cre deleter mice. Podocyte-specific Scribble knockout mice develop normally and display no histological, ultrastructural or clinical abnormalities up to 12 months of age. In addition, no increased susceptibility to glomerular stress could be detected in these mice. In contrast, constitutive Scribble knockout animals die during embryonic development indicating the fundamental importance of Scribble for embryogenesis. Like in podocyte-specific Scribble knockout mice, the development of podocyte foot processes and the slit diaphragm was unaffected in kidney cultures from constitutive Scribble knockout animals. In summary these results indicate that basolateral polarity signaling via Scribble is dispensable for podocyte function, highlighting the unique feature of podocyte development with its significant apical membrane expansions being dominated by apical polarity complexes rather than by basolateral polarity signaling.
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Affiliation(s)
- Björn Hartleben
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Eugen Widmeier
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Nicola Wanner
- Renal Division, University Hospital Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Miriam Schmidts
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Sung Tae Kim
- Renal Division, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lisa Schneider
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Britta Mayer
- Renal Division, University Hospital Freiburg, Freiburg, Germany
| | - Dontscho Kerjaschki
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Jeffrey H. Miner
- Renal Division, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Gerd Walz
- Renal Division, University Hospital Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Tobias B. Huber
- Renal Division, University Hospital Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Freiburg, Germany
- * E-mail:
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25
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Garg P, Rabelink T. Glomerular proteinuria: a complex interplay between unique players. Adv Chronic Kidney Dis 2011; 18:233-42. [PMID: 21782129 DOI: 10.1053/j.ackd.2011.06.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 05/31/2011] [Accepted: 06/01/2011] [Indexed: 11/11/2022]
Abstract
Protein leak in the urine is a harbinger of disruption of the glomerular filtration barrier. It also correlates with disease progression and development of ESRD. At present, therapies are aimed at decreasing proteinuria to decrease further damage to the filter and as a marker of remission. Understanding the mechanism of molecular events that lead to protein leak is vital to developing new therapeutic interventions. There has been tremendous progress over the last decade in identifying gene defects which result in hereditary proteinuric defects. This has led to identifying pathways by which these genes regulate the structure and function of the components of the filtration barrier, namely the podocytes, mesangial cells, endothelial cells, and the basement membrane. Using gene knockout mouse models, a role of tubular cells in regulating proteinuria is also emerging. In this review, we have attempted to present some of the prevailing understanding of the underlying mechanisms and physiology of proteinuria.
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26
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Drossopoulou GI, Tsotakos NE, Tsilibary EC. Impaired transcription factor interplay in addition to advanced glycation end products suppress podocalyxin expression in high glucose-treated human podocytes. Am J Physiol Renal Physiol 2009; 297:F594-603. [DOI: 10.1152/ajprenal.00203.2009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Podocalyxin represents a Wilms’ tumor suppressor protein (WT1)-regulated differentiation marker for glomerular epithelium. We provide evidence concerning mechanisms involved in the regulation of podocalyxin expression following long-term exposure to increased (25 mM) glucose levels. Prolonged culture of conditionally immortalized human podocytes in 25 mM glucose induced suppression of podocalyxin expression both at the protein and mRNA levels, whereas WT1 protein levels remained unaltered. WT1 interacted with another transcription factor, CRE-binding protein (CBP). This association was decreased by 40% in the presence of 25 mM glucose. Chromatin immunoprecipitation assays on chromatin from podocytes cultured in 25 mM glucose revealed reduced WT1 binding to podocalyxin promoter sequences, probably resulting from impaired WT1-CBP interactions. We explored the possible role of glucose-induced adducts (advanced glycation end products; AGEs) in impairing interactions between WT1 and CBP, with the use of aminoguanindine, an inhibitor of AGE formation. Podocytes were cultured in the simultaneous presence of 20 mM aminoguanidine and 25 mM glucose, and podocalyxin protein levels were examined. Aminoguanidine effectively prevented downregulation of podocalyxin protein levels but could not restore podocalyxin levels once expression was suppressed. Thus increased glucose apparently impaired the ability of WT1 to initiate transcription in part by decreased association of WT1 with CBP. Administration of aminoguanidine concomitant with increasing glucose levels in our in vitro model system protected from glucose-induced “silencing” of the podocalyxin gene, suggesting that AGEs play an important role in suppressing its expression in diabetic conditions.
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27
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Abstract
Podocalyxin, a sialomucin most closely related to CD34 and endoglycan, is expressed by kidney podocytes, hematopoietic progenitors, vascular endothelia, and a subset of neurons; aberrant expression has recently been implicated in a range of cancers. Through interactions with several intracellular proteins and at least one extracellular ligand, podocalyxin regulates both adhesion and cell morphology. In the developing kidney, podocalyxin plays an essential role in the formation and maintenance of podocyte foot processes, and its absence results in perinatal lethality. Podocalyxin expression in the hematopoietic system correlates with cell migration and the seeding of new hematopoietic tissues. In addition, it is abnormally expressed in subsets of breast, prostate, liver, pancreatic, and kidney cancer as well as leukemia. Strikingly, it is often associated with the most aggressive cases, and it is likely involved in metastasis. Thus, a thorough investigation of the normal activities of podocalyxin may facilitate the development of new cancer treatment strategies.
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Affiliation(s)
- Julie S Nielsen
- The Biomedical Research Centre, Vancouver, British Columbia, Canada
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28
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Larrucea S, Butta N, Arias-Salgado EG, Alonso-Martin S, Ayuso MS, Parrilla R. Expression of podocalyxin enhances the adherence, migration, and intercellular communication of cells. Exp Cell Res 2008; 314:2004-15. [PMID: 18456258 DOI: 10.1016/j.yexcr.2008.03.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 03/06/2008] [Accepted: 03/06/2008] [Indexed: 11/25/2022]
Abstract
Podocalyxin (PODXL) is an anti-adhesive glycoprotein expressed abundantly in the epithelial cells of kidney glomeruli. In contrast, we report herein that expression of podocalyxin(GFP) (PODXL(GFP)) in CHO cells increased the adherence to immobilized fibronectin, spreading, and migration. The transient knockdown of PODXL or the expression of PODXL lacking the cytosolic carboxyterminal domain (PODXL-Delta(451)) inhibited cell adherence. Moreover, the effect of PODXL was prevented by the ectodomain of podocalyxin (PODXL-Delta(429)), by RGD peptides, or by inhibitors of the vitronectin receptor (alphavbeta3). CHO-PODXL(GFP) also showed adherence to human vascular endothelial cells (HUVEC), exhibiting polarization of granular PODXL and emission of long and thin, spike-like, protrusions with PODXL granules progressing along. We found PODXL colocalized with beta1 integrins at membrane ruffle regions on the leading edge of the cell and a blocking beta1 mAb prevented the spreading of cells. PODXL was also associated with submembrane actin in lamellipodia ruffles, or with vinculin at cell protrusions. The proadhesive effects of PODXL were absent in sialic acid deficient O-glycomutant CHO cells. To conclude, we present evidence indicating that human PODXL enhances the adherence of cells to immobilized ligands and to vascular endothelial cells through a mechanism(s) dependent on the activity of integrins.
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Affiliation(s)
- Susana Larrucea
- Department of Physiopathology, Centro de Investigaciones Biológicas (CSIC), Spain
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29
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Li JJ, Kwak SJ, Jung DS, Kim JJ, Yoo TH, Ryu DR, Han SH, Choi HY, Lee JE, Moon SJ, Kim DK, Han DS, Kang SW. Podocyte biology in diabetic nephropathy. Kidney Int 2007:S36-42. [PMID: 17653209 DOI: 10.1038/sj.ki.5002384] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Glomerular visceral epithelial cells, namely podocytes, are highly specialized cells and give rise to primary processes, secondary processes, and finally foot processes. The foot processes of neighboring podocytes interdigitate, leaving between them filtration slits. These are bridged by an extracellular substance, known as the slit diaphragm, which plays a major role in establishing size-selective barrier to protein loss. Furthermore, podocytes are known to synthesize matrix molecules to the glomerular basement membrane (GBM), including type IV collagen, laminin, entactin, and agrin. Because diabetic nephropathy is clinically characterized by proteinuria and pathologically by glomerular hypertrophy and GBM thickening with foot process effacement, podocytes have been the focus in the field of research on diabetic nephropathy. As a result, many investigations have demonstrated that the diabetic milieu per se, hemodynamic changes, and local growth factors such as transforming growth factor-beta and angiotensin II, which are considered mediators in the pathogenesis of diabetic nephropathy, induce directly and/or indirectly hypertrophy, apoptosis, and structural changes, and increase type IV collagen synthesis in podocytes. This review explores some of the structural and functional changes of podocytes under diabetic conditions and their role in the development and progression of diabetic nephropathy.
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Affiliation(s)
- J J Li
- Department of Internal Medicine, Nephrology and Dialysis Unit, The Affiliated Hospital, YanBian University Medical College, JiLin, China
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30
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Rodríguez RB, Butta N, Larrucea S, Alonso S, Parrilla R. Production and characterization of murine monoclonal antibodies against human podocalyxin. ACTA ACUST UNITED AC 2007; 68:407-17. [PMID: 17092254 DOI: 10.1111/j.1399-0039.2006.00692.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Podocalyxin (podxl) is a protein with a peptide bone of approximately 55.5 kDa that undergoes a post-translational glycosylation, yielding a final molecular mass from approximately 145 to approximately 200 kDa. This protein is normally found covering the vascular side of the epithelial glomerular cells, the podocytes, and its presence is essential to maintain a normal renal function. It has also been reported in other cells and tissues although its function has not been yet clarified. The carboxy-terminal intracellular domain of podxl is nearly 100% identical in most species; however, the ectodomain shows considerable variations although the cysteine residues are conserved. Detection of this protein is elusive, most likely due to differences in post-translational modifications. We aimed at producing murine monoclonal antibodies against human podxl. Immunization with Chinese hamster ovarian -hpodxl-green fluorescence protein live cells yielded five different monoclonal antibodies that were characterized by enzyme-linked immunosorbent assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis/western blot, flow cytometry, immunohistochemistry, and immunoprecipitation. The different behavior of these antibodies suggests that some of them may react against epitopes masked by different glycosylated protein moieties.
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Affiliation(s)
- R B Rodríguez
- Department of Physiopathology and Human Molecular Genetics, Centro de Investigaciones Biológicas (CSIC), 28040-Madrid, Spain
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31
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Huber A, Hudelist G, Knöfler M, Saleh L, Huber JC, Singer CF. Effect of highly purified human chorionic gonadotropin preparations on the gene expression signature of stromal cells derived from endometriotic lesions: potential mechanisms for the therapeutic effect of human chorionic gonadotropin in vivo. Fertil Steril 2007; 88:1232-9. [PMID: 17561010 DOI: 10.1016/j.fertnstert.2007.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Revised: 02/02/2007] [Accepted: 02/02/2007] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To investigate alterations in the overall gene expression profile of endometriosis-derived stroma with increasing concentrations of hCG by using the Affymetrix GeneChip U133 Set. DESIGN In vitro study. SETTING Academic research institution. PATIENT(S) Women undergoing diagnostic laparoscopic surgery for endometriosis. INTERVENTION(S) Increasing concentrations of hCG, added to fibroblast monocultures from endometriotic lesions. RESULT(S) We have found that hCG concentrations of 0.1 U/mL and higher lead to a dose-dependent increase in the expression of 68 genes. Most of the up-regulated genes encoded proteins that are involved in cell adhesion, intercellular communication, extracellular matrix (ECM) remodeling, apoptosis, and inflammation. We then incubated stromal monocultures from nine patients treated with and without 50 U/mL of hCG and performed reverse transcriptase-polymerase chain reaction (RT-PCR) for selected, highly up-regulated genes to validate our DNA array findings and to confirm that the alterations in the gene expression signature are exemplary of patients with endometriosis. CONCLUSION(S) We have shown that hCG induces dose-dependent alterations in the gene expression profile of stromal cells obtained from endometriotic lesions and have, for the first time, identified potential mechanisms by which hCG might exert its therapeutic effect on endometriotic lesions.
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Affiliation(s)
- Ambros Huber
- Division of Obstetrics and Gynecology, Medical University of Vienna, Vienna, Austria
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32
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Steagall RJ, Rusiñol AE, Truong QA, Han Z. HSPA12B Is Predominantly Expressed in Endothelial Cells and Required for Angiogenesis. Arterioscler Thromb Vasc Biol 2006; 26:2012-8. [PMID: 16825593 DOI: 10.1161/01.atv.0000235720.61091.c7] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
HSPA12B is the newest member of HSP70 family of proteins and is enriched in atherosclerotic lesions. This study focused on HSPA12B expression in mice and its involvement in angiogenesis.
Methods and Results—
The expression of HSPA12B in mice and cultured cells was studied by: (1) Northern blot; (2) in situ hybridization; (3) immunostaining with HSPA12B-specific antibodies; and (4) expressing Enhanced-Green-Fluorescent-Protein under the control of the HSPA12B promoter in mice. The function of HSPA12B was probed by an in vitro angiogenesis assay (Matrigel) and a migration assay. Interacting proteins were identified through a yeast two-hybrid screening. HSPA12B is predominantly expressed in vascular endothelium and induced during angiogenesis. In vitro angiogenesis and migration are inhibited in human umbilical vein endothelial cells in the presence of HSPA12B-neutralizing antibodies. HSPA12B interacts with multiple proteins in yeast 2-hybrid system.
Conclusions—
We provide the first evidence to our knowledge that the HSPA12B is predominantly expressed in endothelial cells, required for angiogenesis, and interacts with known angiogenesis regulators. We postulate that HSPA12B provides a new mode of angiogenesis regulation and a novel therapeutic target for angiogenesis-related diseases.
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Affiliation(s)
- Rebecca J Steagall
- Department of Biochemistry and Molecular Biology, East Tennessee State University, College of Medicine, Johnson City, TN 37614, USA
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Abstract
The terminally differentiated podocyte, also called glomerular visceral epithelial cell, are highly specialized cells. They function as a critical size and charge barrier to prevent proteinuria. Podocytes are injured in diabetic and non-diabetic renal diseases. The clinical signature of podocyte injury is proteinuria, with or without loss of renal function owing to glomerulosclerosis. There is an exciting and expanding literature showing that hereditary, congenital, or acquired abnormalities in the molecular anatomy of podocytes leads to proteinuria, and at times, glomerulosclerosis. The change in podocyte shape, called effacement, is not simply a passive process following injury, but is owing to a complex interplay of proteins that comprise the molecular anatomy of the different protein domains of podocytes. These will be discussed in this review. Recent studies have also highlighted that a reduction in podocyte number directly causes proteinuria and glomerulosclerosis. This is owing to several factors, including the relative inability for these cells to proliferate, detachment, and apoptosis. The mechanisms of these events are being elucidated, and are discussed in this review. It is the hope that by delineating the events following injury to podocytes, therapies might be developed to reduce the burden of proteinuric renal diseases.
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Affiliation(s)
- S J Shankland
- Department of Medicine, Division of Nephrology, University of Washington, Seattle, Washington 98195, USA.
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