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Buscher K, Rixen R, Schütz P, Van Marck V, Heitplatz B, Gabriels G, Jehn U, Braun DA, Pavenstädt H, Reuter S. Unveiling systemic responses in kidney transplantation: interplay between the allograft transcriptome and serum proteins. Front Immunol 2024; 15:1398000. [PMID: 39081308 PMCID: PMC11286594 DOI: 10.3389/fimmu.2024.1398000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 07/01/2024] [Indexed: 08/02/2024] Open
Abstract
Immunity, as defined by systems biology, encompasses a holistic response throughout the body, characterized by intricate connections with various tissues and compartments. However, this concept has been rarely explored in kidney transplantation. In this proof-of-concept study, we investigated a direct association between the allograft phenotype and serum protein signatures. Time-matched samples of graft biopsies and blood serum were collected in a heterogeneous cohort of kidney-transplanted patients (n = 15) for bulk RNA sequencing and proteomics, respectively. RNA transcripts exhibit distinct and reproducible, coregulated gene networks with specific functional profiles. We measured 159 serum proteins and investigated correlations with gene expression networks. Two opposing axes-one related to metabolism and the other to inflammation-were identified. They may represent a biological continuum between the allograft and the serum and correlate with allograft function, but not with interstitial fibrosis or proteinuria. For signature validation, we used two independent proteomic data sets (n = 21). Our findings establish a biological link between the allograft transcriptome and the blood serum proteome, highlighting systemic immune effects in kidney transplantation and offering a promising framework for developing allograft-linked biomarkers.
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Affiliation(s)
- Konrad Buscher
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
| | - Rebecca Rixen
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
| | - Paula Schütz
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
| | - Veerle Van Marck
- Institute of Pathology, University Hospital of Münster, Münster, Germany
| | - Barbara Heitplatz
- Institute of Pathology, University Hospital of Münster, Münster, Germany
| | - Gert Gabriels
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
| | - Ulrich Jehn
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
| | - Daniela Anne Braun
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
| | - Hermann Pavenstädt
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
| | - Stefan Reuter
- Division of General Internal Medicine, Nephrology and Rheumatology, Department of Medicine D, University Hospital of Münster, Münster, Germany
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2
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Smith C, du Toit R, Ollewagen T. Potential of bone morphogenetic protein-7 in treatment of lupus nephritis: addressing the hurdles to implementation. Inflammopharmacology 2023; 31:2161-2172. [PMID: 37626268 PMCID: PMC10518293 DOI: 10.1007/s10787-023-01321-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023]
Abstract
Up to 50% of systemic lupus erythematosus (SLE) patients world-wide develop lupus nephritis (LN). In low to middle income countries and in particular in sub-Saharan Africa, where SLE is prevalent with a more aggressive course, LN and end stage renal disease is a major cause of mortality. While developed countries have the funding to invest in SLE and LN research, patients of African descent are often underrepresented in clinical trials. Thus, the complex influence of ethnicity and genetic background on outcome of LN and SLE as a whole, is not fully understood. Several pathophysiological mechanisms including major role players driving LN have been identified. A large body of literature suggest that prevention of fibrosis-which contributes to chronicity of LN-may significantly improve long-term prognosis. Bone morphogenetic protein-7 (BMP-7) was first identified as a therapeutic option in this context decades ago and evidence of its benefit in various conditions, including LN, is ever-increasing. Despite these facts, BMP-7 is not being implemented as therapy in the context of renal disease. With this review, we briefly summarise current understanding of LN pathology and discuss the evidence in support of therapeutic potential of BMP-7 in this context. Lastly, we address the obstacles that need to be overcome, before BMP-7 may become available as LN treatment.
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Affiliation(s)
- Carine Smith
- Experimental Medicine Research Group, Department Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Parow, South Africa.
| | - Riette du Toit
- Division Rheumatology, Department Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Parow, South Africa
| | - Tracey Ollewagen
- Experimental Medicine Research Group, Department Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Parow, South Africa
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3
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Wang Y, Mack JA, Hascall VC, Maytin EV. Transforming Growth Factor-β Receptor-Mediated, p38 Mitogen-Activated Protein Kinase-Dependent Signaling Drives Enhanced Myofibroblast Differentiation during Skin Wound Healing in Mice Lacking Hyaluronan Synthases 1 and 3. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:1683-1698. [PMID: 36063901 PMCID: PMC9765314 DOI: 10.1016/j.ajpath.2022.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 06/30/2022] [Accepted: 08/15/2022] [Indexed: 12/31/2022]
Abstract
Normal myofibroblast differentiation is critical for proper skin wound healing. Neoexpression of α-smooth muscle actin (α-SMA), a marker for myofibroblast differentiation, is driven by transforming growth factor (TGF)-β receptor-mediated signaling. Hyaluronan and its three synthesizing enzymes, hyaluronan synthases (Has 1, 2, and 3), also participate in this process. Closure of skin wounds is significantly accelerated in Has1/3 double-knockout (Has1/3-null) mice. Herein, TGF-β activity and dermal collagen maturation were increased in Has1/3-null healing skin. Cultures of primary skin fibroblasts isolated from Has1/3-null mice had higher levels of TGF-β activity, α-SMA expression, and phosphorylation of p38 mitogen-activated protein kinase at Thr180/Tyr182, compared with wild-type fibroblasts. p38α mitogen-activated protein kinase was a necessary element in a noncanonical TGF-β receptor signaling pathway driving α-SMA expression in Has1/3-null fibroblasts. Myocardin-related transcription factor (MRTF), a cofactor that binds to the transcription factor serum response factor (SRF), was also critical. Nuclear localization of MRTF was increased, and MRTF binding to SRF was enhanced in Has1/3-null fibroblasts. Inhibition of MRTF or SRF expression by RNA interference suppresses α-SMA expression at baseline and diminished its overexpression in Has1/3-null fibroblasts. Interestingly, total matrix metalloproteinase activity was increased in healing skin and fibroblasts from Has1/3-null mice, possibly explaining the increased TGF-β activation.
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Affiliation(s)
- Yan Wang
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio.
| | - Judith A Mack
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio; Department of Dermatology, Dermatology and Plastic Surgery Institute, Cleveland Clinic, Cleveland, Ohio
| | - Vincent C Hascall
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio
| | - Edward V Maytin
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio; Department of Dermatology, Dermatology and Plastic Surgery Institute, Cleveland Clinic, Cleveland, Ohio.
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4
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Guo R, Wang P, Zheng X, Cui W, Shang J, Zhao Z. SGLT2 inhibitors suppress epithelial-mesenchymal transition in podocytes under diabetic conditions via downregulating the IGF1R/PI3K pathway. Front Pharmacol 2022; 13:897167. [PMID: 36225569 PMCID: PMC9550168 DOI: 10.3389/fphar.2022.897167] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 08/23/2022] [Indexed: 01/11/2023] Open
Abstract
Loss of podocyte is a characteristic pathological change of diabetic nephropathy (DN) which is associated with increased proteinuria. Many studies have shown that novel inhibitors of sodium-glucose cotransporter 2 (SGLT2-is), such as dapagliflozin, exert nephroprotective effect on delaying DN progression. However, the mechanisms underlying SGLT2-associated podocyte injury are still not fully elucidated. Here, we generated streptozotocin-induced DN models and treated them with dapagliflozin to explore the possible mechanisms underlying SGLT2 regulation. Compared to mice with DN, dapagliflozin-treated mice exhibited remission of pathological lesions, including glomerular sclerosis, thickening of the glomerular basement membrane (GBM), podocyte injury in the glomeruli, and decreased nephrotoxin levels accompanied by decreased SGLT2 expression. The mRNA expression profiles of these treated mice revealed the significance of the insulin-like growth factor-1 receptor (IGF1R)/PI3K regulatory axis in glomerular injury. KEGG analysis confirmed that the phosphatidylinositol signaling system and insulin signaling pathway were enriched. Western blotting showed that SGLT2-is inhibited the increase of mesenchymal markers (α-SMA, SNAI-1, and ZEB2) and the loss of podocyte markers (nephrin and E-cad). Additionally, SGLT2, IGF1R, phosphorylated PI3K, α-SMA, SNAI-1, and ZEB2 protein levels were increased in high glucose-stimulated human podocytes (HPC) and significantly decreased in dapagliflozin-treated (50 nM and 100 nM) or OSI-906-treated (inhibitor of IGF1R, 60 nM) groups. However, the use of both inhibitors did not enhance this protective effect. Next, we analyzed urine and plasma samples from a cohort consisting of 13 healthy people and 19 DN patients who were administered with (n = 9) or without (n = 10) SGLT2 inhibitors. ELISA results showed decreased circulating levels of IGF1 and IGF2 in SGLT2-is-treated DN patients compared with DN patients. Taken together, our study reported the key role of SGLT2/IGF1R/PI3K signaling in regulating podocyte epithelial-mesenchymal transition (EMT). Modulating IGF1R expression may be a novel approach for DN therapy.
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Affiliation(s)
- Ruixue Guo
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Zhengzhou University, Zhengzhou, China
| | - Peipei Wang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Zhengzhou University, Zhengzhou, China
| | - Xuejun Zheng
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Zhengzhou University, Zhengzhou, China
| | - Wen Cui
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Zhengzhou University, Zhengzhou, China
| | - Jin Shang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Laboratory of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Laboratory Animal Platform of Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China,*Correspondence: Zhanzheng Zhao, ; Jin Shang,
| | - Zhanzheng Zhao
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Laboratory of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China,Laboratory Animal Platform of Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China,*Correspondence: Zhanzheng Zhao, ; Jin Shang,
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5
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Wang S, Chi K, Wu D, Hong Q. Insulin-Like Growth Factor Binding Proteins in Kidney Disease. Front Pharmacol 2022; 12:807119. [PMID: 35002740 PMCID: PMC8728008 DOI: 10.3389/fphar.2021.807119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/08/2021] [Indexed: 12/16/2022] Open
Abstract
The seven members of the insulin-like growth factor (IGF) binding protein family (IGFBPs) were initially considered to be the regulatory proteins of IGFs in the blood circulation, mainly as the subsequent reserve for bidirectional regulation of IGF function during environmental changes. However, in recent years, IGFBPs has been found to have many functions independent of IGFs. The role of IGFBPs in regulating transcription, inducing cell migration and apoptosis is closely related to the occurrence and development of kidney disease. IGFBP-1, IGFBP-3, IGFBP-4 are closely associated with diabetes and diabetic nephropathy. IGFBP-3, IGFBP-4, IGFBP-5, IGFBP-6 are involved in different kidney disease such as diabetes, FSGS and CKD physiological process as apoptosis proteins, IGFBP-7 has been used in clinical practice as a biomarker for early diagnosis and prognosis of AKI. This review focuses on the differential expression and pathogenesis of IGFBPs in kidney disease.
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Affiliation(s)
- Shuqiang Wang
- Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing, China.,Department of Nephrology, Peking University Shenzhen Hospital, Shenzhen, China
| | - Kun Chi
- Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing, China
| | - Di Wu
- Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing, China
| | - Quan Hong
- Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing Key Laboratory of Kidney Diseases, Beijing, China
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6
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Lay AC, Hale LJ, Stowell-Connolly H, Pope RJP, Nair V, Ju W, Marquez E, Rollason R, Hurcombe JA, Hayes B, Roberts T, Gillam L, Allington J, Nelson RG, Kretzler M, Holly JMP, Perks CM, McArdle CA, Welsh GI, Coward RJM. IGFBP-1 expression is reduced in human type 2 diabetic glomeruli and modulates β1-integrin/FAK signalling in human podocytes. Diabetologia 2021; 64:1690-1702. [PMID: 33758952 PMCID: PMC8187213 DOI: 10.1007/s00125-021-05427-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 01/14/2021] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Podocyte loss or injury is one of the earliest features observed in the pathogenesis of diabetic kidney disease (DKD), which is the leading cause of end-stage renal failure worldwide. Dysfunction in the IGF axis, including in IGF binding proteins (IGFBPs), is associated with DKD, particularly in the early stages of disease progression. The aim of this study was to investigate the potential roles of IGFBPs in the development of type 2 DKD, focusing on podocytes. METHODS IGFBP expression was analysed in the Pima DKD cohort, alongside data from the Nephroseq database, and in ex vivo human glomeruli. Conditionally immortalised human podocytes and glomerular endothelial cells were studied in vitro, where IGFBP-1 expression was analysed using quantitative PCR and ELISAs. Cell responses to IGFBPs were investigated using migration, cell survival and adhesion assays; electrical cell-substrate impedance sensing; western blotting; and high-content automated imaging. RESULTS Data from the Pima DKD cohort and from the Nephroseq database demonstrated a significant reduction in glomerular IGFBP-1 in the early stages of human type 2 DKD. In the glomerulus, IGFBP-1 was predominantly expressed in podocytes and controlled by phosphoinositide 3-kinase (PI3K)-forkhead box O1 (FoxO1) activity. In vitro, IGFBP-1 signalled to podocytes via β1-integrins, resulting in increased phosphorylation of focal-adhesion kinase (FAK), increasing podocyte motility, adhesion, electrical resistance across the adhesive cell layer and cell viability. CONCLUSIONS/INTERPRETATION This work identifies a novel role for IGFBP-1 in the regulation of podocyte function and that the glomerular expression of IGFBP-1 is reduced in the early stages of type 2 DKD, via reduced FoxO1 activity. Thus, we hypothesise that strategies to maintain glomerular IGFBP-1 levels may be beneficial in maintaining podocyte function early in DKD.
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Affiliation(s)
- Abigail C Lay
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Lorna J Hale
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | | | - Robert J P Pope
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Viji Nair
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Wenjun Ju
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Eva Marquez
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Ruth Rollason
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Jenny A Hurcombe
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Bryony Hayes
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Timothy Roberts
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Lawrence Gillam
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Jonathan Allington
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Robert G Nelson
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, USA
| | - Matthias Kretzler
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Jeff M P Holly
- IGFs and Metabolic Endocrinology Group, Bristol Medical School, University of Bristol, Bristol, UK
| | - Claire M Perks
- IGFs and Metabolic Endocrinology Group, Bristol Medical School, University of Bristol, Bristol, UK
| | - Craig A McArdle
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Gavin I Welsh
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Richard J M Coward
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK.
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7
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Lamarche É, AlSudais H, Rajgara R, Fu D, Omaiche S, Wiper-Bergeron N. SMAD2 promotes myogenin expression and terminal myogenic differentiation. Development 2021; 148:dev.195495. [PMID: 33462116 DOI: 10.1242/dev.195495] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/24/2020] [Indexed: 11/20/2022]
Abstract
SMAD2 is a transcription factor, the activity of which is regulated by members of the transforming growth factor β (TGFβ) superfamily. Although activation of SMAD2 and SMAD3 downstream of TGFβ or myostatin signaling is known to inhibit myogenesis, we found that SMAD2 in the absence of TGFβ signaling promotes terminal myogenic differentiation. We found that, during myogenic differentiation, SMAD2 expression is induced. Knockout of SMAD2 expression in primary myoblasts did not affect the efficiency of myogenic differentiation but produced smaller myotubes with reduced expression of the terminal differentiation marker myogenin. Conversely, overexpression of SMAD2 stimulated myogenin expression, and enhanced both differentiation and fusion, and these effects were independent of classical activation by the TGFβ receptor complex. Loss of Smad2 in muscle satellite cells in vivo resulted in decreased muscle fiber caliber and impaired regeneration after acute injury. Taken together, we demonstrate that SMAD2 is an important positive regulator of myogenic differentiation, in part through the regulation of Myog.
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Affiliation(s)
- Émilie Lamarche
- Graduate Program in Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Rm 3106Q, Ottawa, Ontario K1H 8M5, Canada
| | - Hamood AlSudais
- Graduate Program in Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Rm 3106Q, Ottawa, Ontario K1H 8M5, Canada
| | - Rashida Rajgara
- Graduate Program in Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Rm 3106Q, Ottawa, Ontario K1H 8M5, Canada
| | - Dechen Fu
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Rm 3106Q, Ottawa, Ontario K1H 8M5, Canada
| | - Saadeddine Omaiche
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Rm 3106Q, Ottawa, Ontario K1H 8M5, Canada
| | - Nadine Wiper-Bergeron
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Rm 3106Q, Ottawa, Ontario K1H 8M5, Canada
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8
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Lepa C, Hoppe S, Stöber A, Skryabin BV, Sievers LK, Heitplatz B, Ciarimboli G, Neugebauer U, Lindenmeyer MT, Cohen CD, Drexler HC, Boor P, Weide T, Pavenstädt H, George B. TrkC Is Essential for Nephron Function and Trans-Activates Igf1R Signaling. J Am Soc Nephrol 2021; 32:357-374. [PMID: 33380522 PMCID: PMC8054883 DOI: 10.1681/asn.2020040424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 11/03/2020] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Injury to kidney podocytes often results in chronic glomerular disease and consecutive nephron malfunction. For most glomerular diseases, targeted therapies are lacking. Thus, it is important to identify novel signaling pathways contributing to glomerular disease. Neurotrophic tyrosine kinase receptor 3 (TrkC) is expressed in podocytes and the protein transmits signals to the podocyte actin cytoskeleton. METHODS Nephron-specific TrkC knockout (TrkC-KO) and nephron-specific TrkC-overexpressing (TrkC-OE) mice were generated to dissect the role of TrkC in nephron development and maintenance. RESULTS Both TrkC-KO and TrkC-OE mice exhibited enlarged glomeruli, mesangial proliferation, basement membrane thickening, albuminuria, podocyte loss, and aspects of FSGS during aging. Igf1 receptor (Igf1R)-associated gene expression was dysregulated in TrkC-KO mouse glomeruli. Phosphoproteins associated with insulin, erb-b2 receptor tyrosine kinase (Erbb), and Toll-like receptor signaling were enriched in lysates of podocytes treated with the TrkC ligand neurotrophin-3 (Nt-3). Activation of TrkC by Nt-3 resulted in phosphorylation of the Igf1R on activating tyrosine residues in podocytes. Igf1R phosphorylation was increased in TrkC-OE mouse kidneys while it was decreased in TrkC-KO kidneys. Furthermore, TrkC expression was elevated in glomerular tissue of patients with diabetic kidney disease compared with control glomerular tissue. CONCLUSIONS Our results show that TrkC is essential for maintaining glomerular integrity. Furthermore, TrkC modulates Igf-related signaling in podocytes.
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Affiliation(s)
- Carolin Lepa
- Medizinische Klinik D, University Hospital Münster, Münster, Germany
| | - Sascha Hoppe
- Medizinische Klinik D, University Hospital Münster, Münster, Germany
| | - Antje Stöber
- Medizinische Klinik D, University Hospital Münster, Münster, Germany
| | - Boris V. Skryabin
- Medical Faculty, Core Facility Transgenic Animal and Genetic Engineering Models (TRAM), Westfälische-Wilhelms-University, Münster, Germany
| | | | - Barbara Heitplatz
- Gerhard-Domagk Institute for Pathology, University Hospital Münster, Münster, Germany
| | | | - Ute Neugebauer
- Medizinische Klinik D, University Hospital Münster, Münster, Germany
| | - Maja T. Lindenmeyer
- III. Medizinische Klinik und Poliklinik, University Hospital Hamburg-Eppendorf, Germany
| | - Clemens D. Cohen
- Klinik für Nieren-, Hochdruck- und Rheumaerkrankungen, München Klinik Harlaching, Germany
| | - Hannes C.A. Drexler
- Mass Spectrometry Unit, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Peter Boor
- Institute of Pathology and Department of Nephrology, University Hospital Aachen, Rheinisch-Westfälische Technische Hochschule Aachen, Aachen, Germany
| | - Thomas Weide
- Medizinische Klinik D, University Hospital Münster, Münster, Germany
| | | | - Britta George
- Medizinische Klinik D, University Hospital Münster, Münster, Germany
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9
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Chen S, Chen H, Zhong Y, Ge Y, Li C, Qiao Z, Zhu J. Insulin-like growth factor-binding protein 3 inhibits angiotensin II-induced aortic smooth muscle cell phenotypic switch and matrix metalloproteinase expression. Exp Physiol 2020; 105:1827-1839. [PMID: 32936966 DOI: 10.1113/ep088927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/15/2020] [Indexed: 12/28/2022]
Abstract
NEW FINDINGS What is the central question of this study? Insulin-like growth factor 1 and its major binding protein insulin-like growth factor binding protein 3 (IGFBP3) are involved in collagen deregulation in several cardiovascular diseases: what is the role of IGFBP3 in thoracic aortic dissection and does it regulate aortic smooth muscle cells' phenotypic switch? What is the main finding and its importance? IGFBP3 inhibits aortic smooth muscle cells' phenotypic switch from a contractile to a synthetic phenotype, decreases matrix metalloproteinase 9 activation and suppresses elastin degradation. These findings provide a better understanding of the pathogenesis of thoracic aortic dissection. ABSTRACT Thoracic aortic dissection (TAD) is characterized by aortic media degeneration and is a highly lethal disease. An aortic smooth muscle cell (AoSMC) phenotypic switch is considered a key pathophysiological change in TAD. Insulin-like growth factor binding protein 3 (IGFBP3) was found to be downregulated in aortic tissues of TAD patients. The present work aimed to study the function of IGFBP3 in AoSMCs' phenotypic switch and matrix metalloproteinase (MMP) expression. We established a mouse model of TAD by angiotensin (Ang) II infusion to β-aminopropionitrile-administrated mice, and found decreased IGFBP3 expression accompanied by aortic dilatation and elastin degradation in vivo. Further, mouse (m)AoSMCs were isolated from mouse thoracic aorta and treated with Ang II. Ang II induced downregulation of IGFBP3 in vitro. To further study the function of IGFBP3, primary mAoSMCs were infected with adenovirus expressing IGFBP3 followed by Ang II induction. Enforced upregulation of IGFBP3 decreased MMP9 expression and activation as well as increasing tissue inhibitor of metalloproteinase (TIMP) 1 expression in Ang II-induced mAoSMCs. No difference was observed in MMP2 and TIMP3 expression. IGFBP3 suppressed subsequent Ang II-induced elastin degradation in vitro. IGFBP3 inhibited Ang II-induced mAoSMCs' phenotypic switch as evidenced by increased smooth muscle actin α-2 (ACTA2) and myosin heavy chain 11 (MYH11) expression and decreased secreted phosphoprotein 1 (SPP1) and vimentin expression. Taken together, the present study demonstrates the role of IGFBP3 in preserving AoSMCs' contractile state and reducing MMP9 activation and thus promoting elastic fibre synthesis, which provides a better understanding of the pathogenesis of TAD.
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Affiliation(s)
- Suwei Chen
- Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Hong Chen
- Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Yongliang Zhong
- Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Yipeng Ge
- Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Chengnan Li
- Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Zhiyu Qiao
- Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Junming Zhu
- Department of Cardiovascular Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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Lopes TG, de Souza ML, da Silva VD, dos Santos M, da Silva WIC, Itaquy TP, Garbin HI, Veronese FV. Markers of renal fibrosis: How do they correlate with podocyte damage in glomerular diseases? PLoS One 2019; 14:e0217585. [PMID: 31220088 PMCID: PMC6586273 DOI: 10.1371/journal.pone.0217585] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/14/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Renal fibrosis is the result of the interaction of cellular and molecular pathways, which is induced by sustained glomerular injury and involves the podocytes and multiple profibrotic factors. In this study, we investigated the correlation of the mRNA expression of podocyte proteins and profibrotic factors with renal fibrosis measured in renal biopsies of patients with primary and secondary glomerulopathies. METHODS Eighty-four adult patients with primary or secondary glomerular diseases and 12 controls were included. Demographic and clinical data were collected. Seventy-two percent of the renal biopsies were done less than one year from clinical disease manifestation. The quantification of the podocyte-associated mRNAs of alpha-actinin-4, podocin, and podocalyxin, as well as of the profibrotic factors TGF-β1, CTGF, and VEGF-A were quantified by real-time polymerase chain reaction. The percent positive area of renal fibrosis was measured by immunohistochemistry staining, using anti-CTGF and anti-HHF35 antibodies and unpolarized Sirius Red. Correlations between the expression of tissue mRNAs and the positive area of fibrosis for the measured markers were made by Spearman's rank correlation coefficient. RESULTS In relation to control biopsies, podocyte-specific proteins were downregulated in podocytopathies, in proliferative nephritis, in diabetic kidney disease (DRD), and in IgA nephropathy (IgAN). Messenger RNA of TGF-β1, CTGF, and VEGF-A was upregulated in patients with podocytopathies and in DRD but not in proliferative nephritis and IgAN. Tissue mRNA expression of TGF-β1, CTGF, and VEGF-A were strongly correlated with renal fibrosis, as measured by HHF35; however, the correlation, albeit significant, was moderate for Sirius Red and weak for CTGF. The percent positive area of renal fibrosis measured by Sirius Red was similar between podocytopathies and DRD and significantly higher in podocytopathies compared to IgAN or proliferative nephritis. CONCLUSIONS In patients with glomerular diseases, the mRNA of TGF-β1, CTGF, and VEGF-A correlated positively with the extent of renal fibrosis, and the positive area of fibrosis was larger in the podocytopathies and in DRD as measured by Sirius Red. The pathways connecting podocyte damage and activation of profibrotic factors to kidney tissue fibrosis need to be better investigated.
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Affiliation(s)
- Tiago Giulianni Lopes
- Postgraduate Program in Medicine: Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- Laboratory of Molecular Biology Applied to Nephrology, Center for Experimental Research, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Maysa Lucena de Souza
- Postgraduate Program in Medicine: Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- Laboratory of Molecular Biology Applied to Nephrology, Center for Experimental Research, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | | | - Mariane dos Santos
- Postgraduate Program in Medicine: Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- Laboratory of Molecular Biology Applied to Nephrology, Center for Experimental Research, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - William Israel Cardoso da Silva
- Laboratory of Molecular Biology Applied to Nephrology, Center for Experimental Research, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Thiago Pereira Itaquy
- Laboratory of Molecular Biology Applied to Nephrology, Center for Experimental Research, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Henrique Iahnke Garbin
- Laboratory of Molecular Biology Applied to Nephrology, Center for Experimental Research, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Francisco Veríssimo Veronese
- Postgraduate Program in Medicine: Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- Laboratory of Molecular Biology Applied to Nephrology, Center for Experimental Research, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
- Division of Nephrology, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
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Arif E, Solanki AK, Srivastava P, Rahman B, Tash BR, Holzman LB, Janech MG, Martin R, Knölker HJ, Fitzgibbon WR, Deng P, Budisavljevic MN, Syn WK, Wang C, Lipschutz JH, Kwon SH, Nihalani D. The motor protein Myo1c regulates transforming growth factor-β-signaling and fibrosis in podocytes. Kidney Int 2019; 96:139-158. [PMID: 31097328 DOI: 10.1016/j.kint.2019.02.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 02/07/2019] [Accepted: 02/14/2019] [Indexed: 01/19/2023]
Abstract
Transforming growth factor-β (TGF-β) is known to play a critical role in the pathogenesis of many progressive podocyte diseases. However, the molecular mechanisms regulating TGF-β signaling in podocytes remain unclear. Using a podocyte-specific myosin (Myo)1c knockout, we demonstrate whether Myo1c is critical for TGF-β-signaling in podocyte disease pathogenesis. Specifically, podocyte-specific Myo1c knockout mice were resistant to fibrotic injury induced by Adriamycin or nephrotoxic serum. Further, loss of Myo1c also protected from injury in the TGF-β-dependent unilateral ureteral obstruction mouse model of renal interstitial fibrosis. Mechanistic analyses showed that loss of Myo1c significantly blunted TGF-β signaling through downregulation of canonical and non-canonical TGF-β pathways. Interestingly, nuclear rather than the cytoplasmic Myo1c was found to play a central role in controlling TGF-β signaling through transcriptional regulation. Differential expression analysis of nuclear Myo1c-associated gene promoters showed that nuclear Myo1c targeted the TGF-β responsive gene growth differentiation factor (GDF)-15 and directly bound to the GDF-15 promoter. Importantly, GDF15 was found to be involved in podocyte pathogenesis, where GDF15 was upregulated in glomeruli of patients with focal segmental glomerulosclerosis. Thus, Myo1c-mediated regulation of TGF-β-responsive genes is central to the pathogenesis of podocyte injury. Hence, inhibiting this process may have clinical application in treating podocytopathies.
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Affiliation(s)
- Ehtesham Arif
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ashish K Solanki
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Pankaj Srivastava
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Bushra Rahman
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Brian R Tash
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Lawrence B Holzman
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael G Janech
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA; College of Charleston, Charleston, South Carolina, USA
| | - René Martin
- Department of Chemistry, TU Dresden, Dresden, Germany
| | | | - Wayne R Fitzgibbon
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Peifeng Deng
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Milos N Budisavljevic
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Wing-Kin Syn
- Department of Gastroenterology & Hepatology, Medical University of South Carolina, Charleston, South Carolina, USA; Section of Gastroenterology, Ralph H Johnson VA Medical Center, Charleston, South Carolina, USA; Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country, (UPV/EHU), Vizcaya, Spain
| | - Cindy Wang
- Department of Gastroenterology & Hepatology, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Joshua H Lipschutz
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Sang-Ho Kwon
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Deepak Nihalani
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA.
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12
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Biological safety and tissue distribution of (16-mercaptohexadecyl)trimethylammonium bromide-modified cationic gold nanorods. Biomaterials 2017; 154:275-290. [PMID: 29149721 DOI: 10.1016/j.biomaterials.2017.10.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/13/2017] [Accepted: 10/27/2017] [Indexed: 12/18/2022]
Abstract
The exceptionally high cellular uptake of gold nanorods (GNRs) bearing cationic surfactants makes them a promising tool for biomedical applications. Given the known specific toxic and stress effects of some preparations of cationic nanoparticles, the purpose of this study was to evaluate, in an in vitro and in vivo in mouse, the potential harmful effects of GNRs coated with (16-mercaptohexadecyl)trimethylammonium bromide (MTABGNRs). Interestingly, even after cellular accumulation of high amounts of MTABGNRs sufficient for induction of photothermal effect, no genotoxicity (even after longer-term accumulation), induction of autophagy, destabilization of lysosomes (dominant organelles of their cellular destination), alterations of actin cytoskeleton, or in cell migration could be detected in vitro. In vivo, after intravenous administration, the majority of GNRs accumulated in mouse spleen followed by lungs and liver. Microscopic examination of the blood and spleen showed that GNRs interacted with white blood cells (mononuclear and polymorphonuclear leukocytes) and thrombocytes, and were delivered to the spleen red pulp mainly as GNR-thrombocyte complexes. Importantly, no acute toxic effects of MTABGNRs administered as 10 or 50 μg of gold per mice, as well as no pathological changes after their high accumulation in the spleen were observed, indicating good tolerance of MTABGNRs by living systems.
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Abstract
The discovery of the transforming growth factor β (TGF-β) family ligands and the realization that their bioactivities need to be tightly controlled temporally and spatially led to intensive research that has identified a multitude of extracellular modulators of TGF-β family ligands, uncovered their functions in developmental and pathophysiological processes, defined the mechanisms of their activities, and explored potential modulator-based therapeutic applications in treating human diseases. These studies revealed a diverse repertoire of extracellular and membrane-associated molecules that are capable of modulating TGF-β family signals via control of ligand availability, processing, ligand-receptor interaction, and receptor activation. These molecules include not only soluble ligand-binding proteins that were conventionally considered as agonists and antagonists of TGF-β family of growth factors, but also extracellular matrix (ECM) proteins and proteoglycans that can serve as "sink" and control storage and release of both the TGF-β family ligands and their regulators. This extensive network of soluble and ECM modulators helps to ensure dynamic and cell-specific control of TGF-β family signals. This article reviews our knowledge of extracellular modulation of TGF-β growth factors by diverse proteins and their molecular mechanisms to regulate TGF-β family signaling.
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Affiliation(s)
- Chenbei Chang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294
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14
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Abstract
Podocytes are highly specialized cells of the kidney glomerulus that wrap around capillaries and that neighbor cells of the Bowman’s capsule. When it comes to glomerular filtration, podocytes play an active role in preventing plasma proteins from entering the urinary ultrafiltrate by providing a barrier comprising filtration slits between foot processes, which in aggregate represent a dynamic network of cellular extensions. Foot processes interdigitate with foot processes from adjacent podocytes and form a network of narrow and rather uniform gaps. The fenestrated endothelial cells retain blood cells but permit passage of small solutes and an overlying basement membrane less permeable to macromolecules, in particular to albumin. The cytoskeletal dynamics and structural plasticity of podocytes as well as the signaling between each of these distinct layers are essential for an efficient glomerular filtration and thus for proper renal function. The genetic or acquired impairment of podocytes may lead to foot process effacement (podocyte fusion or retraction), a morphological hallmark of proteinuric renal diseases. Here, we briefly discuss aspects of a contemporary view of podocytes in glomerular filtration, the patterns of structural changes in podocytes associated with common glomerular diseases, and the current state of basic and clinical research.
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Affiliation(s)
- Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, IL, USA
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Bach LA, Hale LJ. Insulin-like growth factors and kidney disease. Am J Kidney Dis 2014; 65:327-36. [PMID: 25151409 DOI: 10.1053/j.ajkd.2014.05.024] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/03/2014] [Indexed: 11/11/2022]
Abstract
Insulin-like growth factors (IGF-1 and IGF-2) are necessary for normal growth and development. They are related structurally to proinsulin and promote cell proliferation, differentiation, and survival, as well as insulin-like metabolic effects, in most cell types and tissues. In particular, IGFs are important for normal pre- and postnatal kidney development. IGF-1 mediates many growth hormone actions, and both growth hormone excess and deficiency are associated with perturbed kidney function. IGFs affect renal hemodynamics both directly and indirectly by interacting with the renin-angiotensin system. In addition to the IGF ligands, the IGF system includes receptors for IGF-1, IGF-2/mannose-6-phosphate, and insulin, and a family of 6 high-affinity IGF-binding proteins that modulate IGF action. Disordered regulation of the IGF system has been implicated in a number of kidney diseases. IGF activity is enhanced in early diabetic nephropathy and polycystic kidneys, whereas IGF resistance is found in chronic kidney failure. IGFs have a potential role in enhancing stem cell repair of kidney injury. Most IGF actions are mediated by the tyrosine kinase IGF-1 receptor, and inhibitors recently have been developed. Further studies are needed to determine the optimal role of IGF-based therapies in kidney disease.
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Affiliation(s)
- Leon A Bach
- Department of Endocrinology and Diabetes, Alfred Hospital, Melbourne, Victoria, Australia; Department of Medicine (Alfred), Monash University, Melbourne, Victoria, Australia.
| | - Lorna J Hale
- Baker-IDI Research Institute, Melbourne, Victoria, Australia
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16
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Huang G, Dang ZF, Dang YM, Cai W, Li Y, Chen YR, Xie XD. Expression and underlying roles of IGFBP-3 in paclitaxel-treated gastric cancer SGC-7901 cells. Asian Pac J Cancer Prev 2014; 15:5741-5. [PMID: 25081695 DOI: 10.7314/apjcp.2014.15.14.5741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To study the expression of insulin-like growth factor binding proteins (IGFBPs) in paclitaxel-treated gastric cancer SGC-7901 cells, and to further investigate underlying mechanisms. MATERIALS AND METHODS Real time PCR and Western blot assays were applied to detect the mRNA and protein expression of IGFBP-2, -3 and -5 after paclitaxel (10 nM) treatment of SGC-7901 cells. In addition IGFBP-3 expression was silenced by RNA interference to determine effects. Cell viability was determined by MTT assay. Cell cycling and apoptosis were assessed by flow cytometry. RESULTS Compared to the control group, only IGFBP-3 expression was elevated significantly after paclitaxel (10 nM) treatment (p<0.05). Paclitaxel treatment caused cell cycle arrest and apoptosis via downregulating Bcl-2 expression. However, the effect could be abrogated by IGFBP-3 silencing. CONCLUSIONS IGFBP-3 exhibits anti-apoptotic effects on paclitaxel-treated SGC-7901 cells via elevating Bcl-2 expression.
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Affiliation(s)
- Gang Huang
- Gansu Provincial Hospital, Lanzhou, China E-mail :
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17
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Adair BD, Altintas MM, Möller CC, Arnaout MA, Reiser J. Structure of the kidney slit diaphragm adapter protein CD2-associated protein as determined with electron microscopy. J Am Soc Nephrol 2014; 25:1465-73. [PMID: 24511139 DOI: 10.1681/asn.2013090949] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
CD2-associated protein (CD2AP) is a multidomain scaffolding protein that has a critical role in renal function. CD2AP is expressed in glomerular podocytes at the slit diaphragm, a modified adherens junction that comprises the protein filtration barrier of the kidney, and interacts with a number of protein ligands involved in cytoskeletal remodeling, membrane trafficking, cell motility, and cell survival. The structure of CD2AP is unknown. We used electron microscopy and single particle image analysis to determine the three-dimensional structure of recombinant full-length CD2AP and found that the protein is a tetramer in solution. Image reconstruction of negatively stained protein particles generated a structure at 21 Å resolution. The protein assumed a roughly spherical, very loosely packed structure. Analysis of the electron density map revealed that CD2AP consists of a central coiled-coil domain, which forms the tetramer interface, surrounded by four symmetry-related motifs, each containing three globular domains corresponding to the three SH3 domains. The spatial organization exposes the binding sites of all 12 SH3 domains in the tetramer, allowing simultaneous binding to multiple targets. Determination of the structure of CD2AP provides novel insights into the biology of this slit diaphragm protein and lays the groundwork for characterizing the interactions between key molecules of the slit diaphragm that control glomerular filtration.
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Affiliation(s)
- Brian D Adair
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts;
| | - Mehmet M Altintas
- Department of Medicine, Rush University Medical Center, Chicago, Illinois; and
| | - Clemens C Möller
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - M Amin Arnaout
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Developmental and Regenerative Biology, Harvard Medical School, Boston, Massachusetts
| | - Jochen Reiser
- Department of Medicine, Rush University Medical Center, Chicago, Illinois; and
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18
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Jiao Z, Zhang Q, Chang J, Nie D, Li M, Zhu Y, Wang C, Wang Y, Liu F. A protective role of sulforaphane on alveolar epithelial cells exposed to cigarette smoke extract. Exp Lung Res 2013; 39:379-86. [PMID: 24117145 DOI: 10.3109/01902148.2013.830162] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Sulforaphane (SFN) is an excellent antioxidant agent, few of the studies focus on the possible protective role of SFN from cigarette smoke-induced injury on alveolar epithelial cells. OBJECTIVES the aim of the study is to observe the possible protective role of SFN, as well as the function of insulin-like growth factor binding protein-3 (IGFBP-3) in the process. METHODS MTT assay was used to evaluate cell viability after cigarette smoke extract (CSE) and/or SFN exposure, cell cycle was analyzed using flow cytometry, intracellular reactive oxygen species (ROS) level was detected by staining with fluorescent indicator 2', 7'-dichlorofluorescin diacetate (DCFH-DA), finally both real-time quantitative RT-PCR and western blot were employed to observe mRNA and protein levels of IGFBP-3. RESULTS SFN could restore the viability of A549 cells, attenuate G1 block of the cell cycle, and significantly reduce the proportion of sub-G1 cells; at the same time, CSE-induced accumulation of intracellular ROS was decreased by SFN. Interestingly, high expression of IGFBP-3 was found at both transcriptional and translational levels, however by pre-incubation with SFN, the expression of IGFBP-3 was not stimulated by CSE exposure. CONCLUSIONS SFN can antagonize CSE-induced growth arrest of alveolar epithelial cells and IGFBP-3 probably plays an important role in the process.
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Affiliation(s)
- Zongxian Jiao
- Research Institute of Pathology, School of Basic Medical Sciences, Lanzhou University , Lanzhou, Gansu , P.R. China
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The Expression of Intermediate Filament Protein Nestin and Its Association With Cyclin-dependent Kinase 5 in the Glomeruli of Rats With Diabetic Nephropathy. Am J Med Sci 2013; 345:470-7. [DOI: 10.1097/maj.0b013e3182648459] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Investigation of sequential growth factor delivery during cuprizone challenge in mice aimed to enhance oligodendrogliogenesis and myelin repair. PLoS One 2013; 8:e63415. [PMID: 23650566 PMCID: PMC3641124 DOI: 10.1371/journal.pone.0063415] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 04/03/2013] [Indexed: 12/16/2022] Open
Abstract
Repair in multiple sclerosis involves remyelination, a process in which axons are provided with a new myelin sheath by new oligodendrocytes. Bone morphogenic proteins (BMPs) are a family of growth factors that have been shown to influence the response of oligodendrocyte progenitor cells (OPCs) in vivo during demyelination and remyelination in the adult brain. We have previously shown that BMP4 infusion increases numbers of OPCs during cuprizone-induced demyelination, while infusion of Noggin, an endogenenous antagonist of BMP4 increases numbers of mature oligodendrocytes and remyelinated axons following recovery. Additional studies have shown that insulin-like growth factor-1 (IGF-1) promotes the survival of OPCs during cuprizone-induced demyelination. Based on these data, we investigated whether myelin repair could be further enhanced by sequential infusion of these agents firstly, BMP4 to increase OPC numbers, followed by either Noggin or IGF-1 to increase the differentiation and survival of the newly generated OPCs. We identified that sequential delivery of BMP4 and IGF-1 during cuprizone challenge increased the number of mature oligodendrocytes and decreased astrocyte numbers following recovery compared with vehicle infused mice, but did not alter remyelination. However, sequential delivery of BMP4 and Noggin during cuprizone challenge did not alter numbers of oligodendrocytes or astrocytes in the corpus callosum compared with vehicle infused mice. Furthermore, electron microscopy analysis revealed no change in average myelin thickness in the corpus callosum between vehicle infused and BMP4-Noggin infused mice. Our results suggest that while single delivery of Noggin or IGF-1 increased the production of mature oligodendrocytes in vivo in the context of demyelination, only Noggin infusion promoted remyelination. Thus, sequential delivery of BMP4 and Noggin or IGF-1 does not further enhance myelin repair above what occurs with delivery of Noggin alone.
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Cheng X, Zhao X, Khurana S, Bruggeman LA, Kao HY. Microarray analyses of glucocorticoid and vitamin D3 target genes in differentiating cultured human podocytes. PLoS One 2013; 8:e60213. [PMID: 23593176 PMCID: PMC3617172 DOI: 10.1371/journal.pone.0060213] [Citation(s) in RCA: 12] [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: 12/18/2012] [Accepted: 02/22/2013] [Indexed: 12/26/2022] Open
Abstract
Glomerular podocytes are highly differentiated epithelial cells that are key components of the kidney filtration units. Podocyte damage or loss is the hallmark of nephritic diseases characterized by severe proteinuria. Recent studies implicate that hormones including glucocorticoids (ligand for glucocorticoid receptor) and vitamin D3 (ligand for vitamin D receptor) protect or promote repair of podocytes from injury. In order to elucidate the mechanisms underlying hormone-mediated podocyte-protecting activity from injury, we carried out microarray gene expression studies to identify the target genes and corresponding pathways in response to these hormones during podocyte differentiation. We used immortalized human cultured podocytes (HPCs) as a model system and carried out in vitro differentiation assays followed by dexamethasone (Dex) or vitamin D3 (VD3) treatment. Upon the induction of differentiation, multiple functional categories including cell cycle, organelle dynamics, mitochondrion, apoptosis and cytoskeleton organization were among the most significantly affected. Interestingly, while Dex and VD3 are capable of protecting podocytes from injury, they only share limited target genes and affected pathways. Compared to VD3 treatment, Dex had a broader and greater impact on gene expression profiles. In-depth analyses of Dex altered genes indicate that Dex crosstalks with a broad spectrum of signaling pathways, of which inflammatory responses, cell migration, angiogenesis, NF-κB and TGFβ pathways are predominantly altered. Together, our study provides new information and identifies several new avenues for future investigation of hormone signaling in podocytes.
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Affiliation(s)
- Xiwen Cheng
- Department of Biochemistry, School of Medicine, Case Western Reserve University (CWRU) and the Comprehensive Cancer Center of CWRU, Cleveland, Ohio, United States of America
| | - Xuan Zhao
- Department of Biochemistry, School of Medicine, Case Western Reserve University (CWRU) and the Comprehensive Cancer Center of CWRU, Cleveland, Ohio, United States of America
| | - Simran Khurana
- Department of Biochemistry, School of Medicine, Case Western Reserve University (CWRU) and the Comprehensive Cancer Center of CWRU, Cleveland, Ohio, United States of America
| | - Leslie A. Bruggeman
- Rammelkamp Center for Education and Research and Department of Medicine, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Hung-Ying Kao
- Department of Biochemistry, School of Medicine, Case Western Reserve University (CWRU) and the Comprehensive Cancer Center of CWRU, Cleveland, Ohio, United States of America
- * E-mail:
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Abstract
TGF-β (transforming growth factor-β) and BMP-7 (bone morphogenetic protein-7), two key members in the TGF-β superfamily, play important but diverse roles in CKDs (chronic kidney diseases). Both TGF-β and BMP-7 share similar downstream Smad signalling pathways, but counter-regulate each other to maintain the balance of their biological activities. During renal injury in CKDs, this balance is significantly altered because TGF-β signalling is up-regulated by inducing TGF-β1 and activating Smad3, whereas BMP-7 and its downstream Smad1/5/8 are down-regulated. In the context of renal fibrosis, Smad3 is pathogenic, whereas Smad2 and Smad7 are renoprotective. However, this counter-balancing mechanism is also altered because TGF-β1 induces Smurf2, a ubiquitin E3-ligase, to target Smad7 as well as Smad2 for degradation. Thus overexpression of renal Smad7 restores the balance of TGF-β/Smad signalling and has therapeutic effect on CKDs. Recent studies also found that Smad3 mediated renal fibrosis by up-regulating miR-21 (where miR represents microRNA) and miR-192, but down-regulating miR-29 and miR-200 families. Therefore restoring miR-29/miR-200 or suppressing miR-21/miR-192 is able to treat progressive renal fibrosis. Furthermore, activation of TGF-β/Smad signalling inhibits renal BMP-7 expression and BMP/Smad signalling. On the other hand, overexpression of renal BMP-7 is capable of inhibiting TGF-β/Smad3 signalling and protects the kidney from TGF-β-mediated renal injury. This counter-regulation not only expands our understanding of the causes of renal injury, but also suggests the therapeutic potential by targeting TGF-β/Smad signalling or restoring BMP-7 in CKDs. Taken together, the current understanding of the distinct roles and mechanisms of TGF-β and BMP-7 in CKDs implies that targeting the TGF-β/Smad pathway or restoring BMP-7 signalling may represent novel and effective therapies for CKDs.
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de Silva HC, Firth SM, Twigg SM, Baxter RC. Interaction between IGF binding protein-3 and TGFβ in the regulation of adipocyte differentiation. Endocrinology 2012; 153:4799-807. [PMID: 22910030 DOI: 10.1210/en.2011-1444] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The development of white adipose tissue involves both the hypertrophy of existing adipocytes and the proliferation and differentiation of preadipocytes. Adipogenic differentiation is inhibited by TGFβ signaling through Smad2/3, and IGF binding protein-3 (IGFBP-3) is also known to activate Smad2/3 signaling in some cell types. We previously reported that exogenous or overexpressed IGFBP-3 inhibits adipogenesis in 3T3-L1 cells, but the role of endogenous IGFBP-3 in this process, and its possible interaction with TGFβ, is not known. During 10-d adipogenic differentiation initiated by insulin, dexamethasone, and 3-isobutyl-1-methylxanthine, 3T3-L1 cells expressed increasing levels of IGFBP-3 and TGFβ1, secreting over 1000 pg/ml of both proteins. Exogenous recombinant human IGFBP-3 paralleled TGFβ1 in stimulating Smad2 phosphorylation in 3T3-L1 preadipocytes, but no additive effect was observed for the two agents. In contrast, knockdown of endogenous IGFBP-3 by small interfering RNA (siRNA) significantly impaired Smad2 activation by 0.25 ng/ml TGFβ1. Transient expression of human IGFBP-3 significantly inhibited the induction of adipogenic markers adiponectin and resistin, and the appearance of lipid droplets, but down-regulation of endogenous IGFBP-3 by siRNA had little effect on the expression of either marker during the 10-d differentiation, compared with nonsilencing control siRNA. However, down-regulation of endogenous IGFBP-3 using two different siRNA significantly reversed the inhibitory effect of TGFβ1 on both adiponectin and resistin induction. We conclude that IGFBP-3 activates inhibitory Smad signaling in 3T3-L1 cells and that endogenous IGFBP-3 modulates their adipogenic differentiation by regulating cell sensitivity towards the inhibitory effect of TGFβ.
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Affiliation(s)
- Hasanthi C de Silva
- Kolling Institute of Medical Research, Royal North Shore Hospital, University of Sydney, Sydney, New South Wales 2065, Australia
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Marshall JCA, Collins JW, Nakayama J, Horak CE, Liewehr DJ, Steinberg SM, Albaugh M, Vidal-Vanaclocha F, Palmieri D, Barbier M, Murone M, Steeg PS. Effect of inhibition of the lysophosphatidic acid receptor 1 on metastasis and metastatic dormancy in breast cancer. J Natl Cancer Inst 2012; 104:1306-19. [PMID: 22911670 DOI: 10.1093/jnci/djs319] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Previous studies identified the human nonmetastatic gene 23 (NME1, hereafter Nm23-H1) as the first metastasis suppressor gene. An inverse relationship between Nm23-H1 and expression of lysophosphatidic acid receptor 1 gene (LPAR1, also known as EDG2 or hereafter LPA1) has also been reported. However, the effects of LPA1 inhibition on primary tumor size, metastasis, and metastatic dormancy have not been investigated. METHODS The LPA1 inhibitor Debio-0719 or LPA1 short hairpinned RNA (shRNA) was used. Primary tumor size and metastasis were investigated using the 4T1 spontaneous metastasis mouse model and the MDA-MB-231T experimental metastasis mouse model (n = 13 mice per group). Proliferation and p38 intracellular signaling in tumors and cell lines were determined by immunohistochemistry and western blot to investigate the effects of LPA1 inhibition on metastatic dormancy. An analysis of variance-based two-tailed t test was used to determine a statistically significant difference between treatment groups. RESULTS In the 4T1 spontaneous metastasis mouse model, Debio-0719 inhibited the metastasis of 4T1 cells to the liver (mean = 25.2 liver metastases per histologic section for vehicle-treated mice vs 6.8 for Debio-0719-treated mice, 73.0% reduction, P < .001) and lungs (mean = 6.37 lesions per histologic section for vehicle-treated mice vs 0.73 for Debio-0719-treated mice, 88.5% reduction, P < .001), with no effect on primary tumor size. Similar results were observed using the MDA-MB-231T experimental pulmonary metastasis mouse model. LPA1 shRNA also inhibited metastasis but did not affect primary tumor size. In 4T1 metastases, but not primary tumors, expression of the proliferative markers Ki67 and pErk was reduced by Debio-0719, and phosphorylation of the p38 stress kinase was increased, indicative of metastatic dormancy. CONCLUSION The data identify Debio-0719 as a drug candidate with metastasis suppressor activity, inducing dormancy at secondary tumor sites.
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Affiliation(s)
- Jean-Claude A Marshall
- The Women's Cancers Section, Laboratory of Molecular Pharmacology, Center for Cancer Research, National Institutes of Health, Bethesda, MD 20892, USA
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Liu W, Zhang Y, Hao J, Liu S, Liu Q, Zhao S, Shi Y, Duan H. Nestin protects mouse podocytes against high glucose-induced apoptosis by a Cdk5-dependent mechanism. J Cell Biochem 2012; 113:3186-96. [DOI: 10.1002/jcb.24195] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Abstract
PURPOSE OF REVIEW The insulin-like growth factor system plays an important role in renal physiology and it is perturbed in a range of kidney diseases. RECENT FINDINGS Some insulin-like growth factor (IGF) actions in the kidney are mediated by nitric oxide. Growth hormone and IGF-binding proteins may contribute to renal diseases via effects on podocytes and proximal tubule cells. In contrast, growth hormone and IGF-I may counteract the catabolic consequences of end-stage renal disease. Polymorphisms in the IGF system are associated with hypertension. SUMMARY Further studies are needed to determine whether modulating the IGF system may have a role in treating kidney diseases and/or hypertension.
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Oh Y. The insulin-like growth factor system in chronic kidney disease: Pathophysiology and therapeutic opportunities. Kidney Res Clin Pract 2012; 31:26-37. [PMID: 26889406 PMCID: PMC4715090 DOI: 10.1016/j.krcp.2011.12.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 11/24/2011] [Accepted: 11/24/2011] [Indexed: 12/21/2022] Open
Abstract
The growth hormone-insulin-like growth factor-insulin-like growth factor binding protein (GH-IGF-IGFBP) axis plays a critical role in the maintenance of normal renal function and the pathogenesis and progression of chronic kidney disease (CKD). Serum IGF-I and IGFBPs are altered with different stages of CKD, the speed of onset, the amount of proteinuria, and the potential of remission. Recent studies demonstrate that growth failure in children with CKD is due to a relative GH insensitivity and functional IGF deficiency. The functional IGF deficiency in CKD results from either IGF resistance due to increased circulating levels of IGFBPs or IGF deficiency due to increased urinary excretion of serum IGF-IGFBP complexes. In addition, not only GH and IGFs in circulation, but locally produced IGFs, the high-affinity IGFBPs, and low-affinity insulin-like growth factor binding protein-related proteins (IGFBP-rPs) may also affect the kidney. With respect to diabetic kidney disease, there is growing evidence suggesting that GH, IGF-I, and IGFBPs are involved in the pathogenesis of diabetic nephropathy (DN). Thus, prevention of GH action by blockade either at the receptor level or along its signal transduction pathway offers the potential for effective therapeutic opportunities. Similarly, interrupting IGF-I and IGFBP actions also may offer a way to inhibit the development or progression of DN. Furthermore, it is well accepted that the systemic inflammatory response is a key player for progression of CKD, and how to prevent and treat this response is currently of great interest. Recent studies demonstrate existence of IGF-independent actions of high-affinity and low-affinity-IGFBPs, in particular, antiinflammatory action of IGFBP-3 and profibrotic action of IGFBP-rP2/CTGF. These findings reinforce the concept in support of the clinical significance of the IGF-independent action of IGFBPs in the assessment of pathophysiology of kidney disease and its therapeutic potential for CKD. Further understanding of GH-IGF-IGFBP etiopathophysiology in CKD may lead to the development of therapeutic strategies for this devastating disease. It would hold promise to use of GH, somatostatin analogs, IGFs, IGF agonists, GHR and insulin-like growth factor-I receptor (IGF-IR) antagonists, IGFBP displacer, and IGFBP antagonists as well as a combination treatment as therapeutic agents for CKD.
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Affiliation(s)
- Youngman Oh
- Cancer and Metabolic Syndrome Research Laboratory, Department of Pathology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
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Wen D, You L, Zhang Q, Zhang L, Gu Y, Hao CM, Chen J. Upregulation of nestin protects podocytes from apoptosis induced by puromycin aminonucleoside. Am J Nephrol 2011; 34:423-34. [PMID: 21952051 DOI: 10.1159/000331701] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/12/2011] [Indexed: 01/12/2023]
Abstract
BACKGROUND Nestin is an intermediate filament protein widely used as a marker of stem cells or progenitor cells. Nestin is also highly expressed in the glomerular podocyte, a type of terminally differentiated epithelial cell. Little is known about the significance of nestin in podocytes. METHODS Puromycin aminonucleoside (PAN) was injected into the rats to produce a PAN nephrosis model. Transmission electronic microscopy and terminal dUTP nick end-labeling assay were used to examine the podocyte foot process (FP) effacement and apoptosis, respectively. A mouse podocyte cell line was cultured and incubated with PAN. Immunoblot was used to examine the level of nestin expression both in vivo and in vitro. Enhanced green fluorescence protein-tagged plasmids containing nestin shRNA were transfected into the cultured podocytes to silence nestin expression. F-actin arrangement within cultured podocytes was investigated by immunofluorescence, while the apoptosis rate was examined by both Hoechst stain and flow cytometry. RESULTS In the PAN-induced rat nephrosis model, podocyte nestin expression was increased in the absence of apparent podocyte apoptosis, even though the FP was significantly effaced. In the cultured mouse podocytes, PAN upregulated nestin expression in a time-dependent manner within 24 h of treatment. Notably, no significant apoptosis occurred, however knocking down nestin expression resulted in a remarkable derangement of actin cytoskeleton and an increase in apoptosis in the cultured podocytes 24 h after being incubated with PAN. CONCLUSIONS Upregulation of nestin expression during PAN nephrosis could protect podocytes from apoptosis and that this process is mediated by maintaining the regular arrangement of actin cytoskeleton.
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Affiliation(s)
- Donghai Wen
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
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Arampatzis S, Giannakoulas N, Liakopoulos V, Eleftheriadis T, Kourti P, Karasavvidou F, Matsouka P, Stefanidis I. Simultaneous clinical resolution of focal segmental glomerulosclerosis associated with chronic lymphocytic leukaemia treated with fludarabine, cyclophosphamide and rituximab. BMC Nephrol 2011; 12:33. [PMID: 21729272 PMCID: PMC3145560 DOI: 10.1186/1471-2369-12-33] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/05/2011] [Indexed: 11/10/2022] Open
Abstract
Background Although renal involvement in advanced haematological malignancies is common, glomerulonephritis associated with lymphoproliferative disorders is rare, and the related pathogenetic mechanisms are still poorly understood. We present a rare case of chronic lymphocytic leukaemia(CLL)-associated focal segmental glomerulosclerosis with nephrotic-range proteinuria. Case presentation A 53-year-old Caucasian man, previously healthy, with no history of hypertension, alcohol use or smoking presented with rapid weight gain, massive peripheral oedema, and hypertension. Laboratory findings included a white blood cell count of 49,800 cells/mm3 with an absolute lymphocyte count of 47,000 cells/mm3, serum albumin of 2.3 g/dL, urea 65 mg/dL, and creatinine 1.5 mg/dL. A 24-hour urine collection contained 7.1 g protein and significant haematuria. A peripheral blood smear showed mature lymphocytosis and smudge cells. Diagnostic imaging showed mild paraaortic lymphadenopathy with no renal abnormalities. Bone marrow aspiration and trephine biopsy showed diffuse and focal infiltration with B-CLL lymphocytes. Percutaneous renal biopsy revealed total sclerosis in 3/21(14%) of the glomeruli and focal and segmental solidification and sclerosis in 4/21 (19%) glomeruli. A regimen of fludarabine, cyclophosphamide and rituximab was successful in inducing remission of the CLL and clinical resolution of the nephritic-range proteinuria. Conclusions A multidisciplinary approach to monitor both the malignancy and the glomerular lesions is crucial for the optimal management of paraneoplastic glomerulonephritis. Although chemotherapy with fludarabine, cyclophosphamide and rituximab successfully treated CLL-associated nephrotic syndrome in our patient, further studies are required to confirm efficacy in this setting.
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Zhong Y, Lu L, Zhou J, Li Y, Liu Y, Clemmons DR, Duan C. IGF binding protein 3 exerts its ligand-independent action by antagonizing BMP in zebrafish embryos. J Cell Sci 2011; 124:1925-35. [DOI: 10.1242/jcs.082644] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
IGFBP3 is a multi-functional protein that has IGF-dependent and IGF-independent actions in cultured cells. Here we show that the IGF binding domain (IBD), nuclear localization signal (NLS) and transactivation domain (TA) are conserved and functional in zebrafish Igfbp3. The in vivo roles of these domains were investigated by expression of Igfbp3 and its mutants in zebrafish embryos. Igfbp3, and its NLS and TA mutants had equally strong dorsalizing effects. Human IGFBP3 had similar dorsalizing effects in zebrafish embryos. The activities of IBD and IBD+NLS mutants were lower, but they still caused dorsalization. Thus, the IGF-independent action of Igfbp3 is not related to NLS or TA in this in vivo model. We next tested the hypothesis that Igfbp3 exerts its IGF-independent action by affecting Bmp signaling. Co-expression of Igfbp3 with Bmp2b abolished Bmp2b-induced gene expression and inhibited its ventralizing activity. Biochemical assays and in vitro experiments revealed that IGFBP3 bound BMP2 and inhibited BMP2-induced Smad signaling in cultured human cells. In vivo expression of Igfbp3 increased chordin expression in zebrafish embryos by alleviating the negative regulation of Bmp2. The elevated level of Chordin acted together with Igfbp3 to inhibit the actions of Bmp2. Knockdown of Igfbp3 enhanced the ventralized phenotype caused by chordin knockdown. These results suggest that Igfbp3 exerts its IGF-independent actions by antagonizing Bmp signaling and that this mechanism is conserved.
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Affiliation(s)
- Yingbin Zhong
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, and School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, Shandong 266003, China
| | - Ling Lu
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, and School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, Shandong 266003, China
| | - Jianfeng Zhou
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, and School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, Shandong 266003, China
| | - Yun Li
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, and School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, Shandong 266003, China
| | - Yunzhang Liu
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, and School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao, Shandong 266003, China
| | - David R. Clemmons
- Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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Stieger N, Worthmann K, Schiffer M. The role of metabolic and haemodynamic factors in podocyte injury in diabetes. Diabetes Metab Res Rev 2011; 27:207-15. [PMID: 21309047 DOI: 10.1002/dmrr.1164] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Podocyte loss is a common feature in human diabetes as well as in experimental diabetes in rodents. Almost all components of the diabetic milieu lead to serious podocyte stress, driving the cells towards cell cycle arrest and hypertrophy, detachment and apoptosis. Common pathway components induced by high glucose and advanced glycation end-products are reactive oxygen species, cyclin-dependent kinases (p27(Kip1)) and transforming growth factor-beta. In addition, mechanical stresses by stretch or shear forces, insulin deficiency or insulin resistance are independent components resulting in podocyte apoptosis and detachment. In this review, we discuss the common pathways leading to podocyte death as well as novel pathways and concepts of podocyte dedifferentiation and detachment that influence the progression of diabetic glomerulopathy.
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Affiliation(s)
- Nicole Stieger
- Division of Nephrology, Department of Medicine, Hannover Medical School, Carl-Neuberg-Strasse 1, Hannover, Germany
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Cofilin-1 inactivation leads to proteinuria--studies in zebrafish, mice and humans. PLoS One 2010; 5:e12626. [PMID: 20838616 PMCID: PMC2935884 DOI: 10.1371/journal.pone.0012626] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 08/05/2010] [Indexed: 01/31/2023] Open
Abstract
Background Podocytes are highly specialized epithelial cells on the visceral side of the glomerulus. Their interdigitating primary and secondary foot processes contain an actin based contractile apparatus that can adjust to changes in the glomerular perfusion pressure. Thus, the dynamic regulation of actin bundles in the foot processes is critical for maintenance of a well functioning glomerular filtration barrier. Since the actin binding protein, cofilin-1, plays a significant role in the regulation of actin dynamics, we examined its role in podocytes to determine the impact of cofilin-1 dysfunction on glomerular filtration. Methods and Findings We evaluated zebrafish pronephros function by dextran clearance and structure by TEM in cofilin-1 morphant and mutant zebrafish and we found that cofilin-1 deficiency led to foot process effacement and proteinuria. In vitro studies in murine and human podocytes revealed that PMA stimulation induced activation of cofilin-1, whereas treatment with TGF-β resulted in cofilin-1 inactivation. Silencing of cofilin-1 led to an accumulation of F-actin fibers and significantly decreased podocyte migration ability. When we analyzed normal and diseased murine and human glomerular tissues to determine cofilin-1 localization and activity in podocytes, we found that in normal kidney tissues unphosphorylated, active cofilin-1 was distributed throughout the cell. However, in glomerular diseases that affect podocytes, cofilin-1 was inactivated by phosphorylation and observed in the nucleus. Conclusions Based on these in vitro and in vivo studies we concluded cofilin-1 is an essential regulator for actin filament recycling that is required for the dynamic nature of podocyte foot processes. Therefore, we describe a novel pathomechanism of proteinuria development.
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Matsumoto T, Hess S, Kajiyama H, Sakairi T, Saleem MA, Mathieson PW, Nojima Y, Kopp JB. Proteomic analysis identifies insulin-like growth factor-binding protein-related protein-1 as a podocyte product. Am J Physiol Renal Physiol 2010; 299:F776-84. [PMID: 20630940 DOI: 10.1152/ajprenal.00597.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The podocyte secretory proteome may influence the phenotype of adjacent podocytes, endothelial cells, parietal epithelial cells, and tubular epithelial cells but has not been systematically characterized. We have initiated studies to characterize this proteome, with the goal of further understanding the podocyte cell biology. We cultured differentiated conditionally immortalized human podocytes and subjected the proteins in conditioned medium to mass spectrometry. At a false discovery rate of <3%, we identified 111 candidates from conditioned medium, including 44 proteins that have signal peptides or are described as secreted proteins in the UniProt database. As validation, we confirmed that one of these proteins, insulin-like growth factor-binding protein-related protein-1 (IGFBP-rP1), was expressed in mRNA and protein of cultured podocytes. In addition, transforming growth factor-β1 stimulation increased IGFBP-rP1 in conditioned medium. We analyzed IGFBP-rP1 glomerular expression in a mouse model of human immunodeficiency virus-associated nephropathy. IGFBP-rP1 was absent from podocytes of normal mice and was expressed in podocytes and pseudocrescents of transgenic mice, where it was coexpressed with desmin, a podocyte injury marker. We conclude that IGFBP-rP1 may be a product of injured podocytes. Further analysis of the podocyte secretory proteome may identify biomarkers of podocyte injury.
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Affiliation(s)
- Takayuki Matsumoto
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, US Department of Health and Human Services, Bethesda, Maryland, USA
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Yoshikawa M, Hishikawa K, Idei M, Fujita T. Trichostatin a prevents TGF-beta1-induced apoptosis by inhibiting ERK activation in human renal tubular epithelial cells. Eur J Pharmacol 2010; 642:28-36. [PMID: 20553909 DOI: 10.1016/j.ejphar.2010.05.055] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 05/06/2010] [Accepted: 05/31/2010] [Indexed: 12/28/2022]
Abstract
Histone deacetylase (HDAC) inhibitors have recently been reported to have possible reno-protective effects in the last few years. In this study, we found that tricostatin A (TSA), an HDAC inhibitor, prevented transforming growth factor beta1 (TGF-beta1)-induced apoptosis in cultured human renal proximal tubular epithelial cells (RPTECs). TGF-beta1-induced apoptosis via the activation of both caspase-8 and caspase-9 but did not activate the Fas receptor and did not alter Bcl-2 or Bax protein expression. TSA prevented TGF-beta1-induced apoptosis and the activation of caspase-8 and caspase-9 in RPTECs but did not inhibit the TGF-beta1-induced phosphorylation of Smad3 and p38 mitogen-activated protein kinase (MAPK). However, TSA inhibited the TGF-beta1-induced phosphorylation of extracellular signal regulated kinase (ERK), and the MAPK/ERK kinase inhibitor U0126, which specifically inhibits ERK, also prevented TGF-beta1-induced apoptosis. Our results show, for the first time, that TSA inhibits TGF-beta1-induced ERK activation and overrides pro-apoptotic signals like Smad3 and p38 in human RPTECs.
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Affiliation(s)
- Masahiro Yoshikawa
- Department of Internal Medicine, Division of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8655, Japan
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Worthmann K, Peters I, Kümpers P, Saleem M, Becker JU, Agustian PA, Achenbach J, Haller H, Schiffer M. Urinary excretion of IGFBP-1 and -3 correlates with disease activity and differentiates focal segmental glomerulosclerosis and minimal change disease. Growth Factors 2010; 28:129-38. [PMID: 20102313 DOI: 10.3109/08977190903512594] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The glomerular microenvironment is influenced by circulating growth factors that are filtered from the blood stream and pass the glomerular filtration barrier. In this study, we wanted to explore the role of IGF-binding proteins (IGFBPs) in two diseases that concern podocytes. We analyzed glomerular expression and urinary excretion of IGFBP-1, -2, and -3 in patients with focal segmental glomerulosclerosis (FSGS) or minimal change disease (MCD). We found that patients with active FSGS excrete high amounts of podocalyxin positive cells as well as IGFBP-1 and -3. In human podocytes, we can induce mRNA expression of IGFBP-3 in response to TGF-beta and in human microvascular endothelial cells expression of IGFBP-1 and -3 in response to TGF-beta and Bradykinin. We conclude that the local expression of IGFBPs in podocytes and endothelial cells might contribute to the pathogenesis of glomerular disease and that IGFBP-1 and -3 are potential non-invasive markers of FSGS.
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Affiliation(s)
- Kirstin Worthmann
- Department of Medicine/Nephrology, Hannover Medical School, Carl Neuberg Street 1, Hannover, Germany
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Faour WH, Thibodeau JF, Kennedy CRJ. Mechanical stretch and prostaglandin E2 modulate critical signaling pathways in mouse podocytes. Cell Signal 2010; 22:1222-30. [PMID: 20362052 DOI: 10.1016/j.cellsig.2010.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 03/23/2010] [Accepted: 03/24/2010] [Indexed: 11/27/2022]
Abstract
Elevated glomerular capillary pressure (Pgc) and hyperglycemia contribute to glomerular filtration barrier injury observed in diabetic nephropathy (DN). Previous studies showed that hypertensive conditions alone or in combination with a diabetic milieu impact podocyte cellular function which results in podocyte death, detachment or hypertrophy. The present study was aimed at uncovering the initial signaling profile activated by Pgc (mimicked by in vitro mechanical stretch), hyperglycemia (high glucose (HG), 25mM d-glucose) and prostaglandin E(2) (PGE(2)) in conditionally-immortalized mouse podocytes. PGE(2) significantly reduced the active form of AKT by selectively blunting its phosphorylation on S473, but not on T308. AKT inhibition by PGE(2) was reversed following either siRNA-mediated EP(4) knockdown, PKA inhibition (H89), or phosphatase inhibition (orthovanadate). Podocytes treated for 20min with H(2)O(2) (10(-4)M), which mimics reactive oxygen species generation by cells challenged by hyperglycemic or enhanced Pgc conditions, significantly increased the levels of active p38 MAPK, AKT, JNK and ERK1/2. Interestingly, stretch and PGE(2) each significantly reduced H(2)O(2)-mediated AKT phosphorylation and was reversed by pretreatment with orthovanadate while stretch alone reduced GSK-3beta inhibitory phosphorylation at ser-9. Finally, mechanical stretch alone or in combination with HG, induced ERK1/2 and JNK activation, via the EGF receptor since AG1478, a specific EGF receptor kinase inhibitor, blocked this activation. These results show that cellular signaling in podocytes is significantly altered under diabetic conditions (i.e., hyperglycemia and increased Pgc). These changes in MAPKs and AKT activities might impact cellular integrity required for a functional glomerular filtration barrier thereby contributing to the onset of proteinuria in DN.
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Affiliation(s)
- Wissam H Faour
- School of Medicine, Lebanese American University, Byblos, Lebanon.
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Xiao HQ, Shi W, Liu SX, Zhang B, Xu LX, Liang XL, Liang YZ. Podocyte injury is suppressed by 1,25-dihydroxyvitamin D via modulation of transforming growth factor-beta 1/bone morphogenetic protein-7 signalling in puromycin aminonucleoside nephropathy rats. Clin Exp Pharmacol Physiol 2010; 36:682-9. [PMID: 19594554 DOI: 10.1111/j.1440-1681.2008.05133.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. Accumulating evidence suggests that vitamin D and its analogues are renoprotective. However, the precise mechanisms and the molecular targets by which active vitamin D exerts its beneficial effects remain obscure. The objective of the present study was to evaluate the effect of active vitamin D on rats with puromycin aminonucleoside (PAN) nephropathy, a model that is characterized by predominant podocyte injury. 2. The PAN nephropathy rats were created by a single intravenous injection of 100 mg/kg PAN. Changes in renal pathology and podocyte numbers were observed. Real-time polymerase chain reaction (PCR) was performed to examine mRNA expression of nephrin, transforming growth factor (TGF)-beta1 and bone morphogenetic protein (BMP)-7. Protein expression of nephrin, TGF-beta1, BMP-7 and p-Smad2/3 and p-Smad1/5/8 was examined by immunofluorescence, immunohistochemistry and western blotting, respectively. Rats were treated with 1,25(OH)(2)D(3) by gastric gavage at a dose of 2.5 microg/kg per day, starting 2 days before PAN injection and continuing throughout the experiment. 3. A single injection of PAN induced massive proteinuria and elevated serum creatinine on Day 7, both of which were significantly suppressed by 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)). Immunofluorescence and real-time PCR of the podocyte-associated protein nephrin revealed reduced and discontinuous staining and this change was reversed by 1,25(OH)(2)D(3). In PAN nephropathy rats, TGF-beta1 and p-Smad2/3 expression was upregulated, whereas that of BMP-7 and p-Smad1/5/8 was downregulated. Treatment with 1,25(OH)(2)D(3) significantly restored BMP-7/Smad signalling while suppressing TGF-beta1/Smad signalling. 4. In conclusion, 1,25(OH)(2)D(3) can ameliorate podocyte damage and proteinuria induced by PAN. The beneficial effects of 1,25(OH)(2)D(3) on podocytes may be attributable, in part, to direct modulation of TGF-beta1/BMP-7 signalling.
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Affiliation(s)
- Hou-Qin Xiao
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangdong, China
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Reiser J, Mundel P. Is the LPS-mediated proteinuria mouse model relevant to human kidney disease? Nat Med 2009. [DOI: 10.1038/nm0209-133b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Achenbach J, Mengel M, Tossidou I, Peters I, Park JK, Haubitz M, Ehrich JH, Haller H, Schiffer M. Parietal epithelia cells in the urine as a marker of disease activity in glomerular diseases. Nephrol Dial Transplant 2008; 23:3138-45. [PMID: 18458033 DOI: 10.1093/ndt/gfn235] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The detection of viable podocytes in the urine of patients with proteinuric diseases has been described as a non-invasive method to monitor disease activity. Most of the published studies use podocalyxin (PDX) as a podocyte specific marker. METHODS We examined the excretion of viable PDX-positive cells in a random set of spot urine from patients with biopsy-proven focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MGN) or membranoproliferative glomerulonephritis (MPGN) and characterized the excreted cells for podocyte and parietal epithelia markers as well as for proliferation activity. RESULTS We found that untreated patients with active disease excrete high numbers of PDX-positive cells in their urine. In contrast to that we were not able to detect significant amounts of PDX-positive cells in the urine of patients with active minimal change disease (MCD) and patients with FSGS or MGN in full remission. When we further characterized the cells we rarely detected expression of podocyte specific markers in the PDX-positive cells, but at least 50% of the PDX-positive cells were double positive for cytokeratin (CK8-18). Immunohistochemistry of the corresponding renal biopsies showed that 100% of podocytes and parietal cells stained positive for PDX. Semiquantitative analysis revealed that 45% of parietal cells were positive for CK8-18 and 100% of proximal tubular cells. No cells of the glomerular epithelial layer stained positive for CK8-18. CONCLUSIONS PDX-positive cells are lost in the urine in disease states that require podocyte regeneration and are a useful non-invasive marker for glomerular disease activity. These cells are possibly derived from the parietal epithelial layer.
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Affiliation(s)
- Johannes Achenbach
- Mario Schiffer, Division of Nephrology, Department of Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
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Johnson RI, Seppa MJ, Cagan RL. The Drosophila CD2AP/CIN85 orthologue Cindr regulates junctions and cytoskeleton dynamics during tissue patterning. ACTA ACUST UNITED AC 2008; 180:1191-204. [PMID: 18362180 PMCID: PMC2290846 DOI: 10.1083/jcb.200706108] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Developing tissues require cells to undergo intricate processes to shift into appropriate niches. This requires a functional connection between adhesion-mediating events at the cell surface and a cytoskeletal reorganization to permit directed movement. A small number of proteins are proposed to link these processes. Here, we identify one candidate, Cindr, the sole Drosophila melanogaster member of the CD2AP/CIN85 family (this family has been previously implicated in a variety of processes). Using D. melanogaster retina, we demonstrate that Cindr links cell surface junctions (E-cadherin) and adhesion (Roughest) with multiple components of the actin cytoskeleton. Reducing cindr activity leads to defects in local cell movement and, consequently, tissue patterning and cell death. Cindr activity is required for normal localization of Drosophila E-cadherin and Roughest, and we show additional physical and functional links to multiple components of the actin cytoskeleton, including the actin-capping proteins capping protein alpha and capping protein beta. Together, these data demonstrate that Cindr is involved in dynamic cell rearrangement in an emerging epithelium.
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Affiliation(s)
- Ruth I Johnson
- Department of Developmental and Regenerative Biology, Mount Sinai Medical School, New York, NY 10029, USA
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IGFBP3 promoter methylation in colorectal cancer: relationship with microsatellite instability, CpG island methylator phenotype, and p53. Neoplasia 2008; 9:1091-8. [PMID: 18084616 DOI: 10.1593/neo.07760] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2007] [Revised: 10/02/2007] [Accepted: 10/05/2007] [Indexed: 12/14/2022] Open
Abstract
Insulin-like growth factor binding protein 3 (IGFBP3), which is induced by wild-type p53, regulates IGF and interacts with the TGF-beta pathway. IGFBP3 promoter methylation may occur in colorectal cancer with or without the CpG island methylator phenotype (CIMP), which is associated with microsatellite instability (MSI) and TGFBR2 mutation. We examined the relationship between IGFBP3 methylation, p53 expression, CIMP and MSI in 902 population-based colorectal cancers. Utilizing real-time PCR (MethyLight), we quantified promoter methylation in IGFBP3 and eight other CIMP-high-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1). IGFBP3 methylation was far more frequent in non-MSI-high CIMP-high tumors (85% = 35/41) than in MSI-high CIMP-high (49% = 44/90, P < .0001), MSI-high non-CIMP-high (17% = 6/36, P < .0001), and non-MSI-high non-CIMP-high tumors (22% = 152/680, P < .0001). Among CIMP-high tumors, the inverse relationship between MSI and IGFBP3 methylation persisted in p53-negative tumors (P < .0001), but not in p53-positive tumors. IGFBP3 methylation was associated inversely with TGFBR2 mutation in MSI-high non-CIMP-high tumors (P = .02). In conclusion, IGFBP3 methylation is inversely associated with MSI in CIMP-high colorectal cancers, and this relationship is limited to p53-negative tumors. Our data suggest complex relationship between global genomic/epigenomic phenomena (such as MSI/CIMP), single molecular events (e.g., IGFBP3 methylation, TP53 mutation, and TGFBR2 mutation), and the related pathways.
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Mitu GM, Wang S, Hirschberg R. BMP7 is a podocyte survival factor and rescues podocytes from diabetic injury. Am J Physiol Renal Physiol 2007; 293:F1641-8. [PMID: 17804487 DOI: 10.1152/ajprenal.00179.2007] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In early diabetic renal injury, there is podocyte drop-out (but no decrease in the number of other glomerular cells) which is thought to cause glomerular proteinuria and subsequent diabetic glomerular injury. We tested the hypothesis that early diabetic podocyte injury is caused, in part, by downregulation of bone morphogenetic protein-7 (BMP7) and loss of its autocrine function in murine podocytes. High glucose (HG; 25 mM) induces rounding of differentiated podocytes and changes in the distribution of F-actin but without quantitative changes in E-cadherin and the podocyte markers podocin, CD2AP, Neph1, or synaptopodin. HG reduces BMP7 secretion and activity but does not affect BMP receptor levels in murine podocytes. In these cells, BMP7 effectively activates smad5 (but not smad1) and raises p38 phosphorylation [which is also increased by transforming growth factor-β (TGF-β)]. HG as well as TGF-β raise caspase-3 activity, increase apoptosis, and reduce cell survival which is, in part, blocked by BMP7. Knockdown and forced expression studies indicate that smad5 is required as well as sufficient for these actions of BMP7. These findings indicate that BMP7 is a differentiation and survival factor for podocytes, requires smad5, and can reduce diabetic podocyte injury.
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Affiliation(s)
- Grace M Mitu
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, C-1-A, 1124 West Carson St., Torrance, CA 90502, USA
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Löwik MM, Groenen PJTA, Pronk I, Lilien MR, Goldschmeding R, Dijkman HB, Levtchenko EN, Monnens LA, van den Heuvel LP. Focal segmental glomerulosclerosis in a patient homozygous for a CD2AP mutation. Kidney Int 2007; 72:1198-203. [PMID: 17713465 DOI: 10.1038/sj.ki.5002469] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a histologic diagnosis in several kidney diseases characterized by proteinuria and a severe decrease in kidney function. Mutations in several genes were found in patients with primary FSGS, one of which is a CD2-associated protein CD2AP (originally referred to as CMS). This gene encodes an adaptor protein that plays a role in endocytosis, cell motility, and cell survival. Mice deficient in Cd2ap (the mouse homolog) die due to kidney failure, while heterozygous mice develop lesions similar to those of FSGS patients. In the kidney, CD2AP regulates the actin cytoskeleton. The only previously described patient with CD2AP mutation had a severely truncated protein. In this study, we describe a patient with a novel mutation resulting in a premature stop codon yielding a protein truncated by only 4%. This shortened CD2AP protein displays a significantly decreased F-actin binding efficiency in vitro with no expression of the mutated allele in the patient's lymphocytes. Heterozygous expression of the CD2AP mutation in both parents did not lead to any kidney pathology, as both have normal glomerular filtration rates and no proteinuria.
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Affiliation(s)
- M M Löwik
- Department of Pediatric Nephrology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Abstract
Human genetic and in vivo animal studies have helped to define the critical importance of podocytes for kidney function in health and disease. However, as in any other research area, by default these approaches do not allow for mechanistic studies. Such mechanistic studies require the availability of cells grown ex vivo (i.e., in culture) with the ability to directly study mechanistic events and control the environment such that specific hypotheses can be tested. A seminal breakthrough came about a decade ago with the documentation of differentiation in culture of primary rat and human podocytes and the subsequent development of conditionally immortalized differentiated podocyte cell lines that allow deciphering the decisive steps of differentiation and function of 'in vivo' podocytes. Although this paper is not intended to provide a comprehensive review of podocyte biology, nor their role in proteinuric renal diseases or progressive glomerulosclerosis, it will focus specifically on several aspects of podocytes in culture. In particular, we will discuss the scientific and research rationale and need for cultured podocytes, how podocyte cell-culture evolved, and how cultured podocytes are currently being used to uncover novel functions of podocytes that can then be validated in vivo in animal or human studies. In addition, we provide a detailed description of how to properly culture and characterize podocytes to avoid potential pitfalls.
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Affiliation(s)
- S J Shankland
- Division of Nephrology, Department of Medicine, University of Washington, Seattle, Washington, USA
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Tossidou I, Kardinal C, Peters I, Kriz W, Shaw A, Dikic I, Tkachuk S, Dumler I, Haller H, Schiffer M. CD2AP/CIN85 balance determines receptor tyrosine kinase signaling response in podocytes. J Biol Chem 2007; 282:7457-64. [PMID: 17213204 DOI: 10.1074/jbc.m608519200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Defects in podocyte signaling are the basis of many inherited glomerular diseases leading to glomerulosclerosis. CD2-associated protein (CD2AP) is highly expressed in podocytes and is considered to play an important role in the maintenance of the glomerular slit diaphragm. Mice deficient for CD2AP (CD2AP(-/-)) appear normal at birth but develop a rapid onset nephrotic syndrome at 3 weeks of age. We demonstrate that impaired intracellular signaling with subsequent podocyte damage is the reason for this delayed podocyte injury in CD2AP(-/-) mice. We document that CD2AP deficiency in podocytes leads to diminished signal initiation and termination of signaling pathways mediated by receptor tyrosine kinases (RTKs). In addition, we demonstrate that CIN85, a paralog of CD2AP, is involved in termination of RTK signaling in podocytes. CIN85 protein expression is increased in CD2AP(-/-) podocytes in vitro. Stimulation of CD2AP(-/-) podocytes with various growth factors, including insulin-like growth factor 1, vascular endothelial growth factor, and fibroblast growth factor, resulted in a significantly decreased phosphatidylinositol 3-kinase/AKT and ERK signaling response. Moreover, increased CIN85 protein is detectable in podocytes in diseased CD2AP(-/-) mice, leading to decreased base-line activation of ERK and decreased phosphorylation after growth factor stimulation in vivo. Because repression of CIN85 protein leads to a restored RTK signaling response, our results support an important role of CD2AP/CIN85 protein balance in the normal signaling response of podocytes.
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Affiliation(s)
- Irini Tossidou
- Division of Nephrology, Department of Medicine, and Division of Pediatric Hematology and Oncology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany
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