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Hu C, Priceputu E, Cool M, Chrobak P, Bouchard N, Forestier C, Lowell CA, Bénichou S, Hanna Z, Royal V, Jolicoeur P. NEF-Induced HIV-Associated Nephropathy Through HCK/LYN Tyrosine Kinases. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:702-724. [PMID: 36868467 PMCID: PMC10284032 DOI: 10.1016/j.ajpath.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 02/09/2023] [Accepted: 02/15/2023] [Indexed: 03/05/2023]
Abstract
HIV-1-associated nephropathy (HIVAN) is a severe complication of HIV-1 infection. To gain insight into the pathogenesis of kidney disease in the setting of HIV, a transgenic (Tg) mouse model [CD4C/HIV-negative regulator factor (Nef)] was used in which HIV-1 nef expression is under control of regulatory sequences (CD4C) of the human CD4 gene, thus allowing expression in target cells of the virus. These Tg mice develop a collapsing focal segmental glomerulosclerosis associated with microcystic dilatation, similar to human HIVAN. To identify kidney cells permissive to the CD4C promoter, CD4C reporter Tg lines were used. They showed preferential expression in glomeruli, mainly in mesangial cells. Breeding CD4C/HIV Tg mice on 10 different mouse backgrounds showed that HIVAN was modulated by host genetic factors. Studies of gene-deficient Tg mice revealed that the presence of B and T cells and that of several genes was dispensable for the development of HIVAN: those involved in apoptosis (Trp53, Tnfsf10, Tnf, Tnfrsf1b, and Bax), in immune cell recruitment (Ccl3, Ccl2, Ccr2, Ccr5, and Cx3cr1), in nitric oxide (NO) formation (Nos3 and Nos2), or in cell signaling (Fyn, Lck, and Hck/Fgr). However, deletion of Src partially and that of Hck/Lyn largely abrogated its development. These data suggest that Nef expression in mesangial cells through hematopoietic cell kinase (Hck)/Lck/Yes novel tyrosine kinase (Lyn) represents important cellular and molecular events for the development of HIVAN in these Tg mice.
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Affiliation(s)
- Chunyan Hu
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Elena Priceputu
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Marc Cool
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Pavel Chrobak
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Nathalie Bouchard
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Clara Forestier
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Clifford A Lowell
- Department of Laboratory Medicine, University of California, San Francisco, California
| | - Serge Bénichou
- Insitut Cochin, Centre National de la Recherche Scientifique UMR8104, Université Paris Descartes and INSERM U1016, Paris, France
| | - Zaher Hanna
- Laboratory of Molecular Biology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada; Department of Medicine, University of Montreal, Montreal, Quebec, Canada; Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Virginie Royal
- Department of Pathology and Cellular Biology, University of Montreal, Montreal, Quebec, Canada
| | - Paul Jolicoeur
- Department of Microbiology/Immunology, University of Montreal, Montreal, Quebec, Canada; Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada.
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2
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Chen Y, Chen Y, Fu J, Sun Z, Li H, Xiao W, E J, Lo BY, Wang N, Zhang W, Klotman ME, Klotman PE, Kopp JB, D'Agati VD, He JC, Lee K. Tubular-specific expression of HIV protein Vpr leads to severe tubulointerstitial damage accompanied by progressive fibrosis and cystic development. Kidney Int 2023; 103:529-543. [PMID: 36565808 PMCID: PMC9974916 DOI: 10.1016/j.kint.2022.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/21/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
Chronic kidney disease (CKD) is a common cause of morbidity in human immunodeficiency virus (HIV)-positive individuals. HIV infection leads to a wide spectrum of kidney cell damage, including tubular epithelial cell (TEC) injury. Among the HIV-1 proteins, the pathologic effects of viral protein R (Vpr) are well established and include DNA damage response, cell cycle arrest, and cell death. Several in vitro studies have unraveled the molecular pathways driving the cytopathic effects of Vpr in tubular epithelial cells. However, the in vivo effects of Vpr on tubular injury and CKD pathogenesis have not been thoroughly investigated. Here, we use a novel inducible tubular epithelial cell-specific Vpr transgenic mouse model to show that Vpr expression leads to progressive tubulointerstitial damage, interstitial inflammation and fibrosis, and tubular cyst development. Importantly, Vpr-expressing tubular epithelial cells displayed significant hypertrophy, aberrant cell division, and atrophy; all reminiscent of tubular injuries observed in human HIV-associated nephropathy (HIVAN). Single-cell RNA sequencing analysis revealed the Vpr-mediated transcriptomic responses in specific tubular subsets and highlighted the potential multifaceted role of p53 in the regulation of cell metabolism, proliferation, and death pathways in Vpr-expressing tubular epithelial cells. Thus, our study demonstrates that HIV Vpr expression in tubular cells is sufficient to induce HIVAN-like tubulointerstitial damage and fibrosis, independent of glomerulosclerosis and proteinuria. Additionally, as this new mouse model develops progressive CKD with diffuse fibrosis and kidney failure, it can serve as a useful tool to examine the mechanisms of kidney disease progression and fibrosis in vivo.
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Affiliation(s)
- Yuqiang Chen
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA; Department of Nephrology, Shanghai Six Municipal Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ya Chen
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jia Fu
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Zeguo Sun
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Huilin Li
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Wenzhen Xiao
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Jing E
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Benjamin Y Lo
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Niansong Wang
- Department of Nephrology, Shanghai Six Municipal Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Weijia Zhang
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Mary E Klotman
- Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Paul E Klotman
- Division of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Jeffrey B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Vivette D D'Agati
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - John Cijiang He
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA; Renal Section, James J Peters VA Medical Center, Bronx, New York, USA.
| | - Kyung Lee
- Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
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3
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Hall G, Wyatt CM. Mechanisms of Proteinuria in HIV. Front Med (Lausanne) 2021; 8:749061. [PMID: 34722586 PMCID: PMC8548571 DOI: 10.3389/fmed.2021.749061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/09/2021] [Indexed: 11/24/2022] Open
Abstract
Proteinuria is common in the setting of HIV infection, and may reflect comorbid kidney disease, treatment-related nephrotoxicity, and HIV-related glomerular diseases. The mechanisms of podocyte and tubulointerstial injury in HIV-associated nephropathy (HIVAN) have been the subject of intense investigation over the past four decades. The pathologic contributions of viral gene expression, dysregulated innate immune signaling, and ancestry-driven genetic risk modifiers have been explored in sophisticated cellular and whole animal models of disease. These studies provide evidence that injury-induced podocyte dedifferentiation, hyperplasia, cytoskeletal dysregulation, and apoptosis may cause the loss of glomerular filtration barrier integrity and slit diaphragm performance that facilitates proteinuria and tuft collapse in HIVAN. Although the incidence of HIVAN has declined with the introduction of antiretroviral therapy, the collapsing FSGS lesion has been observed in the context of other viral infections and chronic autoimmune disorders, and with the use of interferon-based therapies in genetically susceptible populations. This highlights the fact that the lesion is not specific to HIVAN and that the role of the immune system in aggravating podocyte injury warrants further exploration. This review will summarize our progress in characterizing the molecular mechanisms of podocyte dysfunction in HIVAN and other forms of HIV-associated kidney disease.
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Affiliation(s)
- Gentzon Hall
- Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, NC, United States.,Duke Molecular Physiology Institute, Durham, NC, United States
| | - Christina M Wyatt
- Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, NC, United States.,Duke Clinical Research Institute, Durham, NC, United States
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4
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Torres B, Guardo AC, Squarcia M, Diaz A, Fabra A, Caballero M, Ugarte A, Leal L, Gatell JM, Plana M, Garcia F. Impact of switching to raltegravir and/or adding losartan in lymphoid tissue fibrosis and inflammation in people living with HIV. A randomized clinical trial. HIV Med 2021; 22:674-681. [PMID: 34288357 DOI: 10.1111/hiv.13114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 03/23/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Persistent inflammation and immune activation are associated with lymph node fibrosis and end-organ diseases in treatment-suppressed people living with HIV (PLWH). We investigated the effect of switching to raltegravir and/or adding losartan on lymphoid tissue fibrosis and on the inflammatory/immune-activation mediators in treated HIV patients. METHODS Chronic HIV-infected patients treated with two nucleoside reverse transcriptase inhibitors (2NRTI) and one non-NRTI (NNRTI) or protease inhibitor (PI) during at least 48 weeks were randomized to four groups (n = 48): 2NRTI + efavirenz (EFV), 2NRTI + EFV + losartan, 2NRTI + raltegravir and 2NRTI + raltegravir + losartan for 48 weeks. Tonsillar biopsy and peripheral blood markers of CD4 and CD8 T-lymphocyte activation and senescence, monocyte activation and soluble markers of inflammation were determined at baseline and at week 48 and compared between groups. RESULTS No changes in lymphoid tissue architecture were observed. Adding losartan had no impact on lymphocyte subsets. Conversely, patients who switched to raltegravir showed a higher decrease in all activated [CD4+CD38+HLA-DR+, -0.3 vs. 0.48 (P = 0.033); CD8+CD38+ HLA-DR+, -1.6 vs. 1.3 (P = 0.02)] and senescent [CD4+CD28-CD57+, -0.3 vs. 0.26 (P = 0.04); CD8+CD28-CD57+, -6.1 vs. 3.8 (P = 0.002)] T lymphocytes. In addition, the median CD4/CD8 ratio increased by 0.35 in patients in the raltegravir group vs. 0.03 in the other arms (P = 0.002). Differences between groups in monocyte subpopulations or soluble inflammation markers were not observed. CONCLUSIONS Losartan had no effect on lymphoid fibrosis or immune activation/inflammation. Conversely, switching to a regimen with raltegravir significantly decreased activated and senescent T-lymphocyte subpopulations and increased CD4/CD8 ratio in successfully treated PLWH.
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Affiliation(s)
- B Torres
- Infectious Diseases Department, Hospital Clínic, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - A C Guardo
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - M Squarcia
- Radiology Department, Hospital Clínic, Barcelona, Spain
| | - A Diaz
- Pathology Department, Hospital Clínic, Barcelona, Spain
| | - A Fabra
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - M Caballero
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Otorhinolaryngology Department, Hospital Clínic, Barcelona, Spain
| | - A Ugarte
- Infectious Diseases Department, Hospital Clínic, Barcelona, Spain
| | - L Leal
- Infectious Diseases Department, Hospital Clínic, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - J M Gatell
- Infectious Diseases Department, Hospital Clínic, Barcelona, Spain
| | - M Plana
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - F Garcia
- Infectious Diseases Department, Hospital Clínic, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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5
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Gu X, Zhang S, Zhang T. Abnormal Crosstalk between Endothelial Cells and Podocytes Mediates Tyrosine Kinase Inhibitor (TKI)-Induced Nephrotoxicity. Cells 2021; 10:cells10040869. [PMID: 33921219 PMCID: PMC8070074 DOI: 10.3390/cells10040869] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/04/2021] [Accepted: 04/09/2021] [Indexed: 12/12/2022] Open
Abstract
Vascular endothelial growth factor A (VEGFA) and its receptor VEGFR2 are the main targets of antiangiogenic therapies, and proteinuria is one of the common adverse events associated with the inhibition of the VEGFA/VEGFR2 pathway. The proteinuric kidney damage induced by VEGFR2 tyrosine kinase inhibitors (TKIs) is characterized by podocyte foot process effacement. TKI therapy promotes the formation of abnormal endothelial‒podocyte crosstalk, which plays a key role in TKI-induced podocyte injury and proteinuric nephropathy. This review article summarizes the underlying mechanism by which the abnormal endothelial‒podocyte crosstalk mediates podocyte injury and discusses the possible molecules and signal pathways involved in abnormal endothelial‒podocyte crosstalk. What is more, we highlight the molecules involved in podocyte injury and determine the essential roles of Rac1 and Cdc42; this provides evidence for exploring the abnormal endothelial‒podocyte crosstalk in TKI-induced nephrotoxicity.
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Affiliation(s)
| | | | - Ti Zhang
- Correspondence: ; Tel.: +86-21-6417-5590
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6
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Abstract
Apolipoprotein L1 (APOL1) genetic variants are potent risk factors for glomerular disease, but one or more additional factors are required for expression of glomerular disease. Uncontrolled or poorly controlled human immunodeficiency virus (HIV) infection is the most potent susceptibility factor for APOL1 nephropathy that has been identified to date. APOL1 variants are associated with HIV-associated nephropathy (HIVAN), a podocyte disease, but not with HIV-immune complex disease, primarily a disease of the mesangium. The mechanism by which HIV brings out the latent glomerular disease risk remains to be defined. There are at least two classes of candidate mechanisms to explain the potent interaction between HIV-1 and APOL1. First, APOL1 variant proteins and HIV accessory proteins implicated in HIVAN may target the same or related intracellular pathways in podocytes. Recent data suggest roles for interleukin 1b and transcription factor EB. Second, features of uncontrolled HIV infection, including increased circulating factors such as interferon, may drive APOL1 gene transcription or act upon podocytes in other ways. Deeper probing of APOL1-HIV interactions may yield insights that will aid in understanding HIVAN, APOL1 nephropathy, and podocyte biology.
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Affiliation(s)
- Jeffrey B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
| | - Jurgen Heymann
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Cheryl A Winkler
- Basic Research Laboratory, National Cancer Institute, National Institutes of Health, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD
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7
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Rednor SJ, Ross MJ. Molecular Mechanisms of Injury in HIV-Associated Nephropathy. Front Med (Lausanne) 2018; 5:177. [PMID: 29930940 PMCID: PMC5999756 DOI: 10.3389/fmed.2018.00177] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/22/2018] [Indexed: 11/15/2022] Open
Abstract
HIV-associated nephropathy (HIVAN) is an important cause of secondary focal glomerulosclerosis that occurs primarily in persons of African ancestry with advanced HIV disease. Although HIVAN is characterized by severe proteinuria and rapid progression to end stage renal disease without treatment, the phenotype is markedly attenuated by treatment with antiretroviral medications. HIV infection of glomerular and tubular epithelial cells and subsequent viral gene expression is a key contributor to HIVAN pathogenesis and the kidney can serve as reservoir for HIV strains that differ those in blood. HIV gene expression in renal epithelial cells leads to dysregulation of cellular pathways including cell cycle, inflammation, cell death, and cytoskeletal homeostasis. Polymorphisms in the APOL1 gene explain the marked predilection of HIVAN to occur in persons of African descent and HIVAN. Since HIVAN has the strongest association with APOL1 genotype of any of the APOL1-associated nephropathies, studies to determine the mechanisms by which HIV and APOL1 risk variants together promote kidney injury hold great promise to improve our understanding of the pathogenesis of APOL1-mediated kidney diseases.
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Affiliation(s)
- Samuel J Rednor
- Division of Nephrology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, United States
| | - Michael J Ross
- Division of Nephrology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, United States.,Department of Development and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, United States
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8
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Abstract
Focal segmental glomerulosclerosis (FSGS) is a leading cause of kidney disease worldwide. The presumed etiology of primary FSGS is a plasma factor with responsiveness to immunosuppressive therapy and a risk of recurrence after kidney transplant-important disease characteristics. In contrast, adaptive FSGS is associated with excessive nephron workload due to increased body size, reduced nephron capacity, or single glomerular hyperfiltration associated with certain diseases. Additional etiologies are now recognized as drivers of FSGS: high-penetrance genetic FSGS due to mutations in one of nearly 40 genes, virus-associated FSGS, and medication-associated FSGS. Emerging data support the identification of a sixth category: APOL1 risk allele-associated FSGS in individuals with sub-Saharan ancestry. The classification of a particular patient with FSGS relies on integration of findings from clinical history, laboratory testing, kidney biopsy, and in some patients, genetic testing. The kidney biopsy can be helpful, with clues provided by features on light microscopy (e.g, glomerular size, histologic variant of FSGS, microcystic tubular changes, and tubular hypertrophy), immunofluorescence (e.g, to rule out other primary glomerulopathies), and electron microscopy (e.g., extent of podocyte foot process effacement, podocyte microvillous transformation, and tubuloreticular inclusions). A complete assessment of renal histology is important for establishing the parenchymal setting of segmental glomerulosclerosis, distinguishing FSGS associated with one of many other glomerular diseases from the clinical-pathologic syndrome of FSGS. Genetic testing is beneficial in particular clinical settings. Identifying the etiology of FSGS guides selection of therapy and provides prognostic insight. Much progress has been made in our understanding of FSGS, but important outstanding issues remain, including the identity of the plasma factor believed to be responsible for primary FSGS, the value of routine implementation of genetic testing, and the identification of more effective and less toxic therapeutic interventions for FSGS.
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Affiliation(s)
- Avi Z. Rosenberg
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland; and
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Jeffrey B. Kopp
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland; and
- Kidney Disease Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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9
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Yang N, Sun R, Zhao Y, He J, Zhen L, Guo J, Geng J, Xie Y, Wang J, Feng S, Fei F, Liao X, Zhu X, Wang H, Fu F, Aa J, Wang G. High fat diet aggravates the nephrotoxicity of berberrubine by influencing on its pharmacokinetic profile. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 46:319-327. [PMID: 27525563 DOI: 10.1016/j.etap.2016.08.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/02/2016] [Indexed: 06/06/2023]
Abstract
Berberrubine (BRB), the active metabolite of berberine (BBR), possesses various pharmacological activities. In this study, we found BRB showed not only a stronger lipid-lowering effect than berberine but also a specific nephrotoxicity in mice fed with high fat diet (HFD). To explore the underlying mechanism, the pharmacokinetics of BRB were evaluated. There was a greater in vivo exposure of BRB in C57BL/6J mice fed with HFD than with routine chows, in terms of Cmax, AUC0-t, levels of BRB in kidney and urinary excretion. Moreover, in vitro assessment clearly showed BRB had a toxic effect on renal cell lines, while the primary metabolite, berberrubine-9-O-β-d-glucuronide (BRBG), did not show any obvious toxicity. These results suggested HFD aggravated BRB-induced nephrotoxicity by promoting the in vivo exposure of BRB especially in urine and kidney. Although our previous study indicated BRB could be metabolized into BRBG, BRBG did not show any obvious toxicity in vitro.
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Affiliation(s)
- Na Yang
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Runbin Sun
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Yuqing Zhao
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Jun He
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Le Zhen
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Jiahua Guo
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Jianliang Geng
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Yuan Xie
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Jiankun Wang
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Siqi Feng
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Fei Fei
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Xiaoying Liao
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
| | - Xuanxuan Zhu
- Department of Pharmacology, Clinical Research Institute of Jiangsu Provincial Hospital of Traditional Chinese Medicine, Nanjing 210009, PR China
| | - Hongbo Wang
- Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Pharmacy School at Yantai University, Yantai 264005, PR China
| | - Fenghua Fu
- Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Pharmacy School at Yantai University, Yantai 264005, PR China
| | - Jiye Aa
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China.
| | - Guangji Wang
- Key Lab of Drug Metabolism and Pharmacokinetics, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing 210009, PR China
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10
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Abstract
HIV is a highly adaptive, rapidly evolving virus, which is associated with renal diseases including collapsing glomerulopathy-the classic histomorphological form of HIV-associated nephropathy. Other nephropathies related to viral factors include HIV-immune-complex kidney disease and thrombotic microangiopathy. The distribution of HIV-associated kidney diseases has changed over time and continues to vary across geographic regions worldwide. The reasons for this diversity are complex and include a critical role of APOL1 variants and possibly other genetic factors, disparities in access to effective antiviral therapies, and likely other factors that we do not yet fully understand. The mechanisms responsible for HIVAN, including HIV infection of podocytes and tubular epithelial cells, the molecules responsible for HIV entry, and diverse mechanisms of cell injury, have been the focus of much study. Although combined antiretroviral therapy is effective at preventing and reversing HIVAN, focal segmental glomerulosclerosis, arterionephrosclerosis and diabetic nephropathy are increasingly common in individuals who have received such therapy for many years. These diseases are associated with metabolic syndrome, obesity and premature ageing. Future directions for HIV-related kidney disease will involve regular screening for drug nephrotoxicity and incipient renal disease, as well as further research into the mechanisms by which chronic inflammation can lead to glomerular disease.
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11
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Hamatani H, Hiromura K, Sakairi T, Takahashi S, Watanabe M, Maeshima A, Ohse T, Pippin JW, Shankland SJ, Nojima Y. Expression of a novel stress-inducible protein, sestrin 2, in rat glomerular parietal epithelial cells. Am J Physiol Renal Physiol 2014; 307:F708-17. [PMID: 25056347 DOI: 10.1152/ajprenal.00625.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sestrin 2, initially identified as a p53 target protein, accumulates in cells exposed to stress and inhibits mammalian target of rapamycin (mTOR) signaling. In normal rat kidneys, sestrin 2 was selectively expressed in parietal epithelial cells (PECs), identified by the marker protein gene product 9.5. In adriamycin nephropathy, sestrin 2 expression decreased in PECs on day 14, together with increased expression of phosphorylated S6 ribosomal protein (P-S6RP), a downstream target of mTOR. Sestrin 2 expression was markedly decreased on day 42, coinciding with glomerulosclerosis and severe periglomerular fibrosis. In puromycin aminonucleoside nephropathy, decreased sestrin 2 expression, increased P-S6RP expression, and periglomerular fibrosis were observed on day 9, when massive proteinuria developed. These changes were transient and nearly normalized by day 28. In crescentic glomerulonephritis, sestrin 2 expression was not detected in cellular crescents, whereas P-S6RP increased. In conditionally immortalized cultured PECs, the forced downregulation of sestrin 2 by short hairpin RNA resulted in increased expression of P-S6RP and increased apoptosis. These data suggest that sestrin 2 is involved in PEC homeostasis by regulating the activity of mTOR. In addition, sestrin 2 could be a novel marker of PECs, and decreased expression of sestrin 2 might be a marker of PEC injury.
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Affiliation(s)
- Hiroko Hamatani
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Keiju Hiromura
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan;
| | - Toru Sakairi
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Satoshi Takahashi
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Mitsuharu Watanabe
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Akito Maeshima
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Takamoto Ohse
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan; and
| | - Jeffery W Pippin
- Division of Nephrology, University of Washington, Seattle, Washington
| | | | - Yoshihisa Nojima
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Maebashi, Japan
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12
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Takahashi S, Tomioka M, Hiromura K, Sakairi T, Hamatani H, Watanabe M, Ikeuchi H, Kaneko Y, Maeshima A, Aoki T, Ohnishi H, Matozaki T, Nojima Y. SIRPα signaling regulates podocyte structure and function. Am J Physiol Renal Physiol 2013; 305:F861-70. [PMID: 23842779 DOI: 10.1152/ajprenal.00597.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Signal-regulatory protein-α (SIRPα) is a transmembrane protein that contains tyrosine phosphorylation sites in its cytoplasmic region; two tyrosine phosphatases, SHP-1 and SHP-2, bind to these sites in a phosphorylation-dependent manner and transduce multiple intracellular signals. Recently, SIRPα was identified as one of the major tyrosine-phosphorylated proteins in the glomeruli and found to be expressed in podocytes. In the present study, we examined the role of SIRPα expression in podocytes using knockin mice (C57BL/6 background) expressing mutant SIRPα that lacks a cytoplasmic region (SIRPα-mutant mice). Light microscopic examination revealed no apparent morphological abnormalities in the kidneys of the SIRPα-mutant mice. On the other hand, electron microscopic examination revealed abnormal podocytes with irregular major processes and wider and flattened foot processes in the SIRPα-mutant mice compared with their wild-type counterparts. Significantly impaired renal functions and slight albuminuria were demonstrated in the SIRPα-mutant mice. In addition, adriamycin injection induced massive albuminuria together with focal glomerulosclerosis in the SIRPα-mutant mice, while their wild-type counterparts were resistant to adriamycin-induced nephropathy. These data demonstrate that SIRPα is involved in the regulation of podocyte structure and function as a filtration barrier under both physiological and pathological conditions.
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Affiliation(s)
- Satoshi Takahashi
- Dept. of Medicine and Clinical Science, Gunma Univ. Graduate School of Medicine, 3-39-22 Showa, Maebashi, Gunma 371-8511, Japan.
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13
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Jiang L, Xu L, Song Y, Li J, Mao J, Zhao AZ, He W, Yang J, Dai C. Calmodulin-dependent protein kinase II/cAMP response element-binding protein/Wnt/β-catenin signaling cascade regulates angiotensin II-induced podocyte injury and albuminuria. J Biol Chem 2013; 288:23368-79. [PMID: 23803607 DOI: 10.1074/jbc.m113.460394] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Angiotensin II (Ang II) plays a pivotal role in promoting podocyte dysfunction and albuminuria, however, the underlying mechanisms have not been fully delineated. In this study, we found that Ang II induced Wnt1 expression and β-catenin nuclear translocation in cultured mouse podocytes. Blocking Wnt signaling with Dickkopf-1 (Dkk1) or β-catenin siRNA attenuated Ang II-induced podocyte injury. Ang II could also induce the phosphorylation of calmodulin-dependent protein kinase (CaMK) II and cAMP response element-binding protein (CREB) in cultured podocytes. Blockade of this pathway with CK59 or CREB siRNA could significantly inhibit Ang II-induced Wnt/β-catenin signaling and podocyte injury. In in vivo studies, administration of Ang II promoted Wnt/β-catenin signaling, aggregated podocyte damage, and albuminuria in mice. CK59 could remarkably ameliorate Ang II-induced podocyte injury and albuminuria. Furthermore, ectopic expression of exogenous Dkk1 also attenuated Ang II-induced podocytopathy in mice. Taken together, this study demonstrates that the CaMK II/CREB/Wnt/β-catenin signaling cascade plays an important role in regulating Ang II-induced podocytopathy. Targeting this signaling pathway may offer renal protection against the development of proteinuric kidney diseases.
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Affiliation(s)
- Lei Jiang
- Center for Kidney Disease, 2nd Affiliated Hospital, Nanjing Medical University, 262 North Zhongshan Road, Nanjing, Jiangsu 210003, USA
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14
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Zhou H, Kajiyama H, Tsuji T, Hu X, Leelahavanichkul A, Vento S, Frank R, Kopp JB, Trachtman H, Star RA, Yuen PST. Urinary exosomal Wilms' tumor-1 as a potential biomarker for podocyte injury. Am J Physiol Renal Physiol 2013; 305:F553-9. [PMID: 23761678 DOI: 10.1152/ajprenal.00056.2013] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal Wilms' tumor-1 (WT-1) staining is used to detect podocyte loss in kidney biopsies. We aimed to determine if urinary exosomal WT-1 could serve as a noninvasive biomarker of podocyte injury. We examined WT-1 by Western blot in a human podocyte-like cell line, a mouse model of podocyte injury, and human subjects with podocyte disorders. WT-1 was detected in exosomal fraction of the conditioned media from podocytes and increased 48 h after hTGF-β1 stimulation. Cellular WT-1 decreased in podocytes following hTGF-β1 incubation. In mice with induced podocyte injury, urinary exosomal WT-1 was detected 1 wk earlier than albuminuria and also tracked the effects of angiotensin receptor blocker (ARB) treatment. In addition, urinary exosomal WT-1 levels at 1 wk post-injury correlated with the severity of glomerular injury at 3 wk later. In human subjects, urinary exosomal WT-1 was significantly increased in focal segmental glomerulosclerosis (FSGS) patients compared with healthy volunteers or steroid-sensitive nephrotic syndrome (SSNS) patients. Urinary exosomal WT-1 was also significantly decreased in patients in remission for either FSGS or SSNS or following steroid treatment in six SSNS subjects. We conclude that urinary exosomal WT-1 is a promising noninvasive biomarker with apparent podocyte specificity that can detect early progression and treatment-induced regression of podocyte injury in FSGS or SSNS. These results warrant longitudinal, prospective studies in a large cohort with a range of podocyte diseases.
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Affiliation(s)
- Hua Zhou
- Renal Diagnostics and Therapeutics Unit, NIDDK, National Institutes of Health, 10 Center Dr., Bldg 10, Rm. 3N108, Bethesda, MD 20892-1268.
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15
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Sharma M, Magenheimer LK, Home T, Tamano KN, Singhal PC, Hyink DP, Klotman PE, Vanden Heuvel GB, Fields TA. Inhibition of Notch pathway attenuates the progression of human immunodeficiency virus-associated nephropathy. Am J Physiol Renal Physiol 2013; 304:F1127-36. [PMID: 23389453 DOI: 10.1152/ajprenal.00475.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The Notch pathway is an evolutionarily conserved signaling cascade that is critical in kidney development and has also been shown to play a pathogenetic role in a variety of kidney diseases. We have previously shown that the Notch signaling pathway is activated in human immunodeficiency virus-associated nephropathy (HIVAN) as well as in a rat model of the disease. In this study, we examined Notch signaling in the well established Tg26 mouse model of HIVAN. Notch signaling components were distinctly upregulated in the kidneys of these mice as well as in immortalized podocytes derived from these mice. Notch1 and Notch4 were upregulated in the Tg26 glomeruli, and Notch4 was also expressed in tubules. Notch ligands Jagged1, Jagged2, Delta-like1, and Delta-like 4 were all upregulated in the tubules of Tg26 mice, but glomeruli showed minimal expression of Notch ligands. To examine a potential pathogenetic role for Notch in HIVAN, Tg26 mice were treated with GSIXX, a gamma secretase inhibitor that blocks Notch signaling. Strikingly, GSIXX treatment resulted in significant improvement in both histological kidney injury scores and renal function. GSIXX-treated Tg26 mice also showed diminished podocyte proliferation and dedifferentiation, cellular hallmarks of the disease. Moreover, GSIXX blocked podocyte proliferation in vitro induced by HIV proteins Nef and Tat. These studies suggest that Notch signaling can promote HIVAN progression and that Notch inhibition may be a viable treatment strategy for HIVAN.
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Affiliation(s)
- Madhulika Sharma
- Department of Internal Medicine, The Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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16
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Kumar D, Plagov A, Yadav I, Torri DD, Sayeneni S, Sagar A, Rai P, Adabala M, Lederman R, Chandel N, Ding G, Malhotra A, Singhal PC. Inhibition of renin activity slows down the progression of HIV-associated nephropathy. Am J Physiol Renal Physiol 2012; 303:F711-20. [PMID: 22718888 DOI: 10.1152/ajprenal.00643.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the present study, we evaluated the effect of inhibition of renin activity (aliskiren) on the progression of renal lesions in two different mouse models (Vpr and Tg26) of human immunodeficiency virus (HIV)-associated nephropathy (HIVAN). In protocol A, Vpr mice were fed either water (C-VprA) or doxycycline [Doxy (D-VprA)] in their drinking water for 6 wk. In protocols B and C, Vpr mice received either normal saline (C-VprB/C), Doxy + normal saline (D-VprB/C), or Doxy + aliskiren (AD-VprB/C) for 6 wk (protocol B) or 12 wk (protocol C). In protocols D and E, Vpr mice were fed Doxy for 6 wk followed by kidney biopsy. Subsequently, half of the mice were administered either normal saline (D-VprD/E) or aliskiren (AD-VprD/E) for 4 wk (protocol D) or 8 (protocol E) wk. All D-VprA mice showed renal lesions in the form of focal segmental glomerular sclerosis and dilatation of tubules. In protocols B and C, aliskiren diminished both progression of renal lesions and proteinuria. In protocol C, aliskiren also diminished (P < 0.01) the rise in blood urea. In all groups, Doxy-treated mice displayed increased serum ANG I levels (the product of plasma renin activity); on the other hand, all aliskiren-treated mice displayed diminished serum ANG I levels. Renal tissues of D-VprC displayed increased ANG II content; however, aliskiren attenuated renal tissue ANG II production in AD-VprC. In protocol D, AD-VprD showed a 24.2% increase in the number of sclerosed glomeruli compared with 139.2% increase in sclerosed glomeruli in D-VprD (P < 0.01) from their baseline. The attenuating effect of aliskiren on the progression of renal lesions continued in AD-VprE. Aliskiren also diminished blood pressure, proteinuria, and progression of renal lesions in Tg26 mice. These findings indicate that inhibition of renin activity has a potential to slow down the progression of HIVAN.
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Affiliation(s)
- Dileep Kumar
- Division of Kidney Diseases and Hypertension, North Shore Long Island Jewish Medical Center, New Hyde Park, NY, USA
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Yadav A, Kumar D, Salhan D, Rattanavich R, Maheshwari S, Adabala M, Ding G, Singhal PC. Sirolimus modulates HIVAN phenotype through inhibition of epithelial mesenchymal transition. Exp Mol Pathol 2012; 93:173-81. [PMID: 22579465 DOI: 10.1016/j.yexmp.2012.04.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 10/28/2022]
Abstract
HIV-associated nephropathy (HIVAN) is characterized by proliferative phenotype in the form of collapsing glomerulopathy and microcystic dilatation of tubules. Recently, epithelial mesenchymal transition (EMT) of renal cells has been demonstrated to contribute to the pathogenesis of proliferative HIVAN phenotype. We hypothesized that sirolimus would modulate HIVAN phenotype by attenuating renal cell EMT. In the present study, we evaluated the effect of sirolimus on the development of renal cell EMT as well as on display of HIVAN phenotype in a mouse model of HIVAN (Tg26). Tg26 mice receiving normal saline (TgNS) showed enhanced proliferation of both glomerular and tubular cells when compared to control mice-receiving normal saline (CNS); on the other hand, Tg26 mice receiving sirolimus (TgS) showed attenuated renal cell proliferation when compared with TgNS. TgNS also showed increased number of α-SMA-, vimentin-, and FSP1-positive cells (glomerular as well as tubular) when compared with CNS; however, TgS showed reduced number of SMA, vimentin, and FSP1+ve renal cells when compared to TgNS. Interestingly, sirolimus preserved renal epithelial cell expression of E-cadherin in TgS. Since sirolimus attenuated renal cell ZEB expression (a repressor of E-cadherin transcription), it appears that sirolimus may be attenuating renal cell EMT by preserving epithelial cell E-cadherin expression.
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Affiliation(s)
- Anju Yadav
- Immunology Center, Feinstein Institute for Medical Research, North Shore-Long Island Jewish Health System, Manhasset, NY 11030, United States
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18
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Shimizu A, Zhong J, Miyazaki Y, Hosoya T, Ichikawa I, Matsusaka T. ARB protects podocytes from HIV-1 nephropathy independently of podocyte AT1. Nephrol Dial Transplant 2012; 27:3169-75. [PMID: 22422866 DOI: 10.1093/ndt/gfs033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Angiotensin I-converting enzyme inhibitors and angiotensin receptor blockers protect podocytes more effectively than other anti-hypertensive drugs. Transgenic rats overexpressing angiotensin II Type 1 (AT1) receptor selectively in podocytes have been shown to develop glomerulosclerosis. The prevailing hypothesis is that angiotensin II has a capacity of directly acting on the AT1 receptor of podocytes to induce injury. We therefore investigated the mechanism of reno-protective effect of AT1 receptor in a mouse model of HIV-1 nephropathy. METHODS We generated transgenic mice carrying the HIV-1 gene (control/HIV-1) or both HIV-1 gene and podocyte-selectively nullified AT1 gene (AT1KO/HIV-1). In these mice, we measured urinary protein or albumin excretion and performed histological analysis. RESULTS At 8 months of age, AT1KO/HIV-1 (n = 13) and control/HIV-1 (n = 15) mice were statistically indistinguishable with respect to urinary albumin/creatinine ratio (median 2.5 versus 9.1 mg/mg), glomerulosclerosis (median 0.63 versus 0.45 on 0-4 scale) and downregulation of nephrin (median 6.90 versus 7.02 on 0-8 scale). In contrast to the observed lack of effect of podocyte-specific AT1KO, systemic AT1 inhibition with AT1 blocker (ARB) significantly attenuated proteinuria and glomerulosclerosis in HIV-1 mice. CONCLUSION These results indicate that the protective effect of ARB is mediated through its receptors on cells other than podocytes, such as efferent arteriolar smooth muscle cells.
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Affiliation(s)
- Akihiro Shimizu
- Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
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19
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Salhan D, Sagar A, Kumar D, Rattanavich R, Rai P, Maheshwari S, Adabala M, Husain M, Ding G, Malhotra A, Chander PN, Singhal PC. HIV-associated nephropathy: role of AT2R. Cell Signal 2012; 24:734-41. [PMID: 22108089 PMCID: PMC3258382 DOI: 10.1016/j.cellsig.2011.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 10/22/2011] [Accepted: 11/04/2011] [Indexed: 10/15/2022]
Abstract
AT(1)R has been reported to play an important role in the progression of HIV-associated nephropathy (HIVAN); however, the effect of AT(2)R has not been studied. Age and sex matched control (FVB/N) and Tg26 mice aged 4, 8, and 16weeks were studied for renal tissue expression of AT(1)R and AT(2)R (Protocol A). Renal tissue mRNA expression of AT(2)R was lower in Tg26 mice when compared with control mice. In Protocol B, Tg26 mice were treated with either saline, telmisartan (TEL, AT(1) blocker), PD123319 (PD, AT(2)R blocker), or TEL+PD for two weeks. TEL-receiving Tg26 (TRTg) displayed less advanced glomerular and tubular lesions when compared with saline-receiving Tg26 (SRTg). TRTgs displayed enhanced renal tissue AT(2)R expression when compared to SRTgs. Diminution of renal tissue AT(2)R expression was associated with advanced renal lesions in SRTgs; whereas, upregulation of AT(2)R expression in TRTgs was associated with attenuated renal lesions. PD-receiving Tg26 mice (PDRTg) did not show any alteration in the course of HIVAN; whereas, PD+TEL-receiving Tg26 (PD-TRTg) showed worsening of renal lesions when compared to TRTgs. Interestingly, plasma as well as renal tissues of Tg26 mice displayed several fold higher concentration of Ang III, a ligand of AT(2)R.
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Affiliation(s)
- Divya Salhan
- Division of Kidney Diseases and Hypertension, North Shore-LIJ Health System, Great Neck, NY 11021, United States
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Takagi N, Tanizawa T, Kon V, Fogo AB, Ichikawa I, Ma J. Mineralocorticoid Receptor Blocker Protects against Podocyte-Dependent Glomerulosclerosis. NEPHRON EXTRA 2012; 2:17-26. [PMID: 22479265 PMCID: PMC3318935 DOI: 10.1159/000334961] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Background We previously showed that angiotensin type 1 receptor (AT1) blocker (ARB) attenuates glomerular injury in Nphs1-hCD25 (NEP25) transgenic mice, a model of selective podocyte injury. However, subsequent studies in NEP25 mice with podocyte-specific deficiency of AT1 revealed that the protective effects of ARB are not through the podocyte AT1, thereby raising the possibility that the protective effects of ARB involve mineralocorticoids. Methods NEP25 mice were treated with the mineralocorticoid receptor blocker (MRB) spironolactone (25 mg/kg/day, n = 10), the ARB losartan (250 mg/kg/day, n = 11), both (ARB+MRB, n = 8) or vehicle (Vehicle, n = 9) from day −7 to day 9 of induction of podocyte injury. Results Although MRB did not reduce systolic blood pressure or proteinuria, addition of MRB to ARB significantly attenuated glomerulosclerosis (glomerulosclerosis index: ARB+MRB 1.67 ± 0.19 vs. MRB 2.01 ± 0.29, ARB 2.35 ± 0.19, and Vehicle 2.25 ± 0.26, p < 0.05) and preserved the number of WT1-positive podocytes (ARB+MRB 152.5 ± 9.7 vs. MRB 117.2 ± 9.0 or ARB 113.6 ± 7.4, and ARB+MRB vs. Vehicle 97.5 ± 4.0 per glomerulus; p < 0.05). Conclusion These data suggest that, while MRB does not attenuate proteinuria caused by podocyte-specific injury, it provides protective effects against glomerulosclerosis that is independent of systemic blood pressure.
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Affiliation(s)
- Nobuaki Takagi
- Division of Nephrology, Department of Pediatrics, Vanderbilt University, Nashville, Tenn., USA
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Abstract
The classic kidney disease of HIV infection, HIV-associated nephropathy (HIVAN), is an aggressive form of collapsing focal segmental glomerulosclerosis with accompanying tubular and interstitial lesions. HIVAN was first described among African-Americans and Haitian immigrants with advanced HIV disease, an early suggestion of a strong genetic association. This genetic susceptibility was recently linked to polymorphisms on chromosome 22 in individuals of African descent. The association with advanced HIV infection and evidence from HIV-transgenic mice suggested the possibility that HIV directly infects the kidney and that specific HIV gene expression induces host cellular pathways that are responsible for HIVAN pathogenesis. Although combination antiretroviral therapy has substantially reduced the impact of HIVAN in the United States, continued growth of the HIV epidemic in susceptible African populations may have important public health implications. This article reviews recent progress in the pathogenesis and treatment of HIVAN and describes the changing epidemiology of HIV-related kidney disease.
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Affiliation(s)
- Christina M Wyatt
- Department of Medicine, Division of Nephrology, Mount Sinai School Medicine, New York, New York 10029, USA.
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Angiotensin II contributes to podocyte injury by increasing TRPC6 expression via an NFAT-mediated positive feedback signaling pathway. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:1719-32. [PMID: 21839714 DOI: 10.1016/j.ajpath.2011.06.033] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 05/09/2011] [Accepted: 06/10/2011] [Indexed: 01/31/2023]
Abstract
The transient receptor potential channel C6 (TRPC6) is a slit diaphragm-associated protein in podocytes involved in regulating glomerular filter function. Gain-of-function mutations in TRPC6 cause hereditary focal segmental glomerulosclerosis (FSGS), and several human acquired proteinuric diseases show increased glomerular TRPC6 expression. Angiotensin II (AngII) is a key contributor to glomerular disease and may regulate TRPC6 expression in nonrenal cells. We demonstrate that AngII regulates TRPC6 mRNA and protein levels in cultured podocytes and that AngII infusion enhances glomerular TRPC6 expression in vivo. In animal models for human FSGS (doxorubicin nephropathy) and increased renin-angiotensin system activity (Ren2 transgenic rats), glomerular TRPC6 expression was increased in an AngII-dependent manner. TRPC6 expression correlated with glomerular damage markers and glomerulosclerosis. We show that the regulation of TRPC6 expression by AngII and doxorubicin requires TRPC6-mediated Ca(2+) influx and the activation of the Ca(2+)-dependent protein phosphatase calcineurin and its substrate nuclear factor of activated T cells (NFAT). Accordingly, calcineurin inhibition by cyclosporine decreased TRPC6 expression and reduced proteinuria in doxorubicin nephropathy, whereas podocyte-specific inducible expression of a constitutively active NFAT mutant increased TRPC6 expression and induced severe proteinuria. Our findings demonstrate that the deleterious effects of AngII on podocytes and its pathogenic role in glomerular disease involve enhanced TRPC6 expression via a calcineurin/NFAT positive feedback signaling pathway.
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Bigé N, Lanternier F, Viard JP, Kamgang P, Daugas E, Elie C, Jidar K, Walker-Combrouze F, Peraldi MN, Isnard-Bagnis C, Servais A, Lortholary O, Noël LH, Bollée G. Presentation of HIV-associated nephropathy and outcome in HAART-treated patients. Nephrol Dial Transplant 2011; 27:1114-21. [PMID: 21745806 DOI: 10.1093/ndt/gfr376] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Among the numerous renal diseases observed in human immunodeficiency virus (HIV) patients, HIV-associated nephropathy (HIVAN) is a major cause of end-stage renal disease (ESRD). The purpose of our study was to describe the presentation and outcome of HIVAN in the era of highly active antiretroviral therapy (HAART). METHODS We analysed clinical features and outcome of 57 patients with histologically proven HIVAN diagnosed between 2000 and 2009 in four teaching hospitals in Paris, France. RESULTS This series was characterized by median age of 41 years (18-58), frequent African origin (87%), severe renal dysfunction [estimated glomerular filtration rate (eGFR) 20 mL/min/1.73m(2) (1-68)], high-grade proteinuria [4.1 g/day (0.6-16.8)], high proportion of sclerotic glomeruli [31.5% (0-95)], high HIV load [4.5 log copies/mL (0-6.7)] and low CD4+ count [127/mm(3) (3-713)]. Nevertheless, a non-negligible proportion of patients did not present with these typical features. Follow-up data were available for 51 patients. ESRD occurred in 30 patients (58.8%). Median renal survival was 40 months. Baseline characteristics significantly associated with ESRD were as follows: severity of renal dysfunction, percentage of sclerotic glomeruli, time from HIV infection to HIVAN diagnosis longer than 1 year and prior exposure to antiretroviral drugs. There was an insignificant trend towards better renal outcome being associated with viral suppression during follow-up. Use of renin-angiotensin system (RAS) blockers was associated with higher renal survival (P < 0.05). CONCLUSION Despite HAART, HIVAN led to ESRD in more than half of the cases. Early recognition of the disease is crucial to start HAART and RAS blockers before irreversible renal injury.
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Affiliation(s)
- Naïke Bigé
- Department of Nephrology, Necker-Enfants Malades Hospital, Assistance Publique-Hôpitaux de Paris, Paris Descartes University, Paris, France
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Kogan M, Rappaport J. HIV-1 accessory protein Vpr: relevance in the pathogenesis of HIV and potential for therapeutic intervention. Retrovirology 2011; 8:25. [PMID: 21489275 PMCID: PMC3090340 DOI: 10.1186/1742-4690-8-25] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 04/13/2011] [Indexed: 01/11/2023] Open
Abstract
The HIV protein, Vpr, is a multifunctional accessory protein critical for efficient viral infection of target CD4+ T cells and macrophages. Vpr is incorporated into virions and functions to transport the preintegration complex into the nucleus where the process of viral integration into the host genome is completed. This action is particularly important in macrophages, which as a result of their terminal differentiation and non-proliferative status, would be otherwise more refractory to HIV infection. Vpr has several other critical functions including activation of HIV-1 LTR transcription, cell-cycle arrest due to DCAF-1 binding, and both direct and indirect contributions to T-cell dysfunction. The interactions of Vpr with molecular pathways in the context of macrophages, on the other hand, support accumulation of a persistent reservoir of HIV infection in cells of the myeloid lineage. The role of Vpr in the virus life cycle, as well as its effects on immune cells, appears to play an important role in the immune pathogenesis of AIDS and the development of HIV induced end-organ disease. In view of the pivotal functions of Vpr in virus infection, replication, and persistence of infection, this protein represents an attractive target for therapeutic intervention.
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Affiliation(s)
- Michael Kogan
- Department of Neuroscience, Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140, USA
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Abstract
INTRODUCTION The hypoxia-inducible factor (HIF) system mediates the body's response to hypoxia, locally, inducing angiogenesis and a shift to anaerobic metabolism, and systemically, increasing red cell mass in anemia. HIF prolyl hydroxylases (HIF-PH) modify HIF, decreasing its activity. Increasing HIF activity through inhibition of HIF-PH may provide an alternative treatment for anemia and may protect against damage related to ischemia-reperfusion. AREAS COVERED The review discusses the basic science underpinnings of the HIF system and the clinical effects of the HIF system and its pharmacologic manipulation. EXPERT OPINION Manipulation of the HIF system may improve outcomes in anemia by bypassing the effective iron deficiency found in anemia of chronic disease and by increasing red cell mass without supraphysiologic increases in erythropoietin. HIF-PH may also find a clinical use in the prevention of ischemia-reperfusion damage in strokes, cardiac ischemia, ischemic renal failure, etc.
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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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Mikulak J, Singhal PC. HIV-1 and kidney cells: better understanding of viral interaction. Nephron Clin Pract 2010; 115:e15-21. [PMID: 20407278 DOI: 10.1159/000312882] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
HIV-associated nephropathy (HIVAN) is the most common disease affecting untreated seropositive patients of African descent. Besides genetic (African descent) and HIV-1 infection (environmental), specific host factors such as activation of renin-angiotensin-aldosterone system (RAAS) have also been demonstrated to play a role in the manifestation of HIVAN. The recent identification of MYH9 as susceptible allele is a key step forward in our understanding for the pathogenesis of focal glomerulosclerosis in people of African-American descent. HIV-1 transgenic models have significantly advanced our knowledge base in terms of role of HIV-1 genes in general and individual gene in particular in the development of renal lesions mimicking HIVAN. These studies suggest that viral replication is not needed for the development of renal lesions. Renal biopsy data from HIVAN patients suggest that renal epithelial cells express HIV-1 genes and thus it may be sufficient to invoke HIVAN phenotype in the presence of specific host and genetic factors. On the other hand, immune response to infection may be required to induce HIV-1 associated immune complex kidney disease (HIVICK). Since renal cell lack conventional HIV-1 receptors, HIV-1 entry into renal cells has been a mystery. Recently, non-conventional pathways have been demonstrated to facilitate HIV-1 entry into renal cells in in vitro studies. These include presence of DEC-205 receptors in renal tubular cells and lipid rafts in podocytes. However, HIV-1 entry through these pathways only allows non-productive infection. It appears that the presence of specific genetic and host factors in in vivo conditions may be facilitating the development of the productive HIV-1 infection in kidney cells.
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Affiliation(s)
- Joanna Mikulak
- Feinstein Institute for Medical Research and Long Island Jewish Medical Center, New Hyde Park, NY, USA
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Matsusaka T, Asano T, Niimura F, Kinomura M, Shimizu A, Shintani A, Pastan I, Fogo AB, Ichikawa I. Angiotensin receptor blocker protection against podocyte-induced sclerosis is podocyte angiotensin II type 1 receptor-independent. Hypertension 2010; 55:967-73. [PMID: 20142565 DOI: 10.1161/hypertensionaha.109.141994] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In the present study, we tested the hypothesis that the renoprotective effect of an angiotensin receptor blocker depends on the angiotensin II type 1 (AT(1)) receptor on podocytes. For this purpose, we generated podocyte-specific knockout mice for the AT(1) gene (Agtr1a) and crossed with NEP25, in which selective podocyte injury can be induced by immunotoxin, anti-Tac(Fv)-PE38. Four weeks after the addition of anti-Tac(Fv)-PE38, urinary albumin:creatinine ratio was not attenuated in Agtr1a knockout/NEP25 mice (n=18) compared with that in control NEP25 mice (n=13; 8.08+/-2.41 in knockout versus 4.84+/-0.73 in control). Both strains of mice showed similar degrees of sclerosis (0.66+/-0.17 versus 0.82+/-0.27 on a 0 to 4 scale) and downregulation of nephrin (5.78+/-0.45 versus 5.65+/-0.58 on a 0 to 8 scale). In contrast, AT(1) antagonist or an angiotensin I-converting enzyme inhibitor, but not hydralazine, remarkably attenuated proteinuria and sclerosis in NEP25 mice. Moreover, continuous angiotensin II infusion induced microalbuminuria similarly in both Agtr1a knockout and wild-type mice. Thus, angiotensin inhibition can protect podocytes and prevent the development of glomerulosclerosis independent of podocyte AT(1). Possible mechanisms include inhibitory effects on AT(1) of other cells or through mechanisms independent of AT(1). Our study further demonstrates that measures that directly affect only nonpodocyte cells can have beneficial effects even when sclerosis is triggered by podocyte-specific injury.
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Affiliation(s)
- Taiji Matsusaka
- Departments of Pediatrics, Vanderbilt University Medical Center, Nashville, Tenn, USA.
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Rosenstiel P, Gharavi A, D'Agati V, Klotman P. Transgenic and infectious animal models of HIV-associated nephropathy. J Am Soc Nephrol 2009; 20:2296-304. [PMID: 19497967 DOI: 10.1681/asn.2008121230] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
HIV-associated nephropathy (HIVAN) is a major cause of HIV-related morbidity and mortality. Transgenic and infectious models of HIVAN faithfully recapitulate the human disease and are important tools in advancing our understanding of disease pathogenesis, genetic susceptibility, and therapeutic intervention beyond the inhibition of viral replication. This review discusses the available transgenic murine models and infectious models of HIVAN in mice, rats, nonhuman primates, and felines. Particular emphasis is given to cell type-specific HIV expression as well as partial HIV genome expression used to map HIV-1 Nef and Vpr as pathologic determinants.
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Affiliation(s)
- Paul Rosenstiel
- Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
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30
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Sakurai N, Kuroiwa T, Ikeuchi H, Hiramatsu N, Takeuchi S, Tomioka M, Shigehara T, Maeshima A, Kaneko Y, Hiromura K, Kopp JB, Nojima Y. Fluvastatin prevents podocyte injury in a murine model of HIV-associated nephropathy. Nephrol Dial Transplant 2009; 24:2378-83. [PMID: 19188342 DOI: 10.1093/ndt/gfp012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Recent studies have reported that statins have renoprotective effects, independent from lowering plasma cholesterol. In this study, we examined whether statins were beneficial in a murine model of HIV-associated nephropathy (HIVAN). METHODS We used conditional transgenic mice that express one of the HIV-1 accessory genes, vpr, selectively in podocytes using podocin promoter and the Tet-on system. These mice develop aggressive collapsing focal segmental glomerular sclerosis with massive proteinuria and deterioration of renal function within 4 weeks following heminephrectomy and doxycycline administration. Fluvastatin was administrated simultaneously with doxycycline, and the effect was compared with untreated controls after 4 weeks. RESULTS Fluvastatin at 10 mg/kg/day significantly decreased urinary albumin excretion (87 versus 11 mg/day, P < 0.01) and glomerular sclerosis (2.4 versus 1.0, P < 0.01, assessed by semi-quantitative scoring: 0-4). Fluvastatin also decreased serum creatinine and total cholesterol, but these differences were not statistically significant (0.36 versus 0.32 mg/dl, P = 0.35; 492 versus 378 mg/dl, P = 0.11, respectively). Phenotypic changes in podocytes, as indicated by the downregulation of nephrin, Wilms' tumour 1 and synaptopodin, along with upregulation of proliferating cell nuclear antigen, were attenuated by fluvastatin, suggesting its protective effects against podocyte injuries. In cultured podocytes, angiotensin II treatment decreased nephrin expression to 13% of basal levels, which was reversed to 58% by adding fluvastatin. CONCLUSIONS In conclusion, fluvastatin was effective in treating experimental HIVAN. The beneficial effect of this drug might be caused, in part, by preserving nephrin expression in podocytes against angiotensin II-mediated injury.
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Affiliation(s)
- Noriyuki Sakurai
- Department of Medicine and Clinical Science, Gunma University Graduate School of Medicine, Gunma, Japan
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31
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Abstract
PURPOSE OF REVIEW Focal and segmental glomerulosclerosis occurs due to a defect in the glomerular filtration barrier. This review highlights contributions from the past year that have enhanced our understanding of the pathophysiology of focal and segmental glomerulosclerosis with emphasis on discoveries which may lead to the identification of therapeutic targets. RECENT FINDINGS Slit diaphragm proteins have become increasingly important in signal transduction and in mediating downstream events. Actin polymerization occurs after the podocin-nephrin-Neph-1 complex is phosphorylated by Src kinase and Fyn. Recent studies of angiotensin receptor antagonists, corticosteroids and erythropoietin unravel new mechanisms that ameliorate proteinuria by targeting the cell cycle within the podocyte. The discovery that an N-acetylmannosamine kinase (MNK) mutant mouse has glomerulopathy is suggestive that human sialylation pathways may represent therapeutic targets. Proteinuria before podocyte effacement demonstrated in laminin-beta2 null mice highlights the importance of the glomerular basement membrane. Interferon-beta reduced proteinuria in three models of kidney injury, showing greatest effect on glomerular endothelial cells in vitro. SUMMARY Basic research has illuminated mechanisms by which classic therapies have antiproteinuric effects directly on the podocyte. As knowledge expands with improved molecular techniques, understanding signaling pathways in health and proteinuric states should lead to potential therapeutic targets in focal and segmental glomerulosclerosis.
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Sacristán D, Marques M, Zamorano-León JJ, Luque M, Armengol J, Del Castillo J, Martín J, Delpón E, Ramos-Mozo P, de Prada TP, Tamargo J, Barrientos A, Macaya C, López-Farré A. Modifications by Olmesartan medoxomil treatment of the platelet protein profile of moderate hypertensive patients. Proteomics Clin Appl 2008; 2:1300-12. [PMID: 21136924 DOI: 10.1002/prca.200700021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Indexed: 11/06/2022]
Abstract
Olmesartan medoxomil is a new angiotensin II receptor blockers (ARB) which exhibits pleiotropic effects that are not fully understood. Our aims were: i) to determine the effect of Olmesartan medoxomil on blood pressure, lipid profile and renal functionality in moderately hypertensive patients with non-controlled blood pressure, ii) to determine if Olmesartan medoxomil may exert anti-inflammatory effects and modify the expression profile of platelet proteins. Thirteen moderate hypertensive patients with non-controlled systolic blood pressure (SBP) and renal function classified as Kidney Disease Outcome Quality Initiative stage 2-3 were included. Patients were treated with Olmesartan medoxomil (20 mg/day) for 6 months. SBP, proteinuria and the plasma levels of cholesterol and low density lipoprotein (LDL)-cholesterol were reduced after the treatment. Olmesartan medoxomil did not modify the circulating plasma levels of a number of proteins associated with inflammation, but reduced the expression level of different platelet proteins including tropomyosin-β chain isotypes 3 and 4, serotransferrin isotypes 1 to 5, the leukocyte elastase inhibitor and the chloride intracellular channel-protein isotype 1. The expression of the gelsolin precursor isotype 4 was increased in the platelets after the treatment. In summary, Olmesartan medoxomil reduced SBP, total and LDL-cholesterol plasma levels and urinary protein excretion and induced changes in the expression of platelet proteins which may be related to some action of the drug at the megakaryocyte level.
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Affiliation(s)
- Daniel Sacristán
- Cardiovascular Research Unit of the Cardiology Department, Hospital Clínico San Carlos, Madrid, Spain
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Zhou H, Cheruvanky A, Hu X, Matsumoto T, Hiramatsu N, Cho ME, Berger A, Leelahavanichkul A, Doi K, Chawla LS, Illei GG, Kopp JB, Balow JE, Austin HA, Yuen PST, Star RA. Urinary exosomal transcription factors, a new class of biomarkers for renal disease. Kidney Int 2008; 74:613-21. [PMID: 18509321 DOI: 10.1038/ki.2008.206] [Citation(s) in RCA: 186] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Urinary exosomes are excreted from all nephron segments and constitute a rich source of intracellular kidney injury biomarkers. To study whether they contain transcription factors, we collected urine from two acute kidney injury models (cisplatin or ischemia-reperfusion), two podocyte injury models (puromycin-treated rats or podocin-Vpr transgenic mice) and from patients with focal segmental glomerulosclerosis, acute kidney injury and matched controls. Exosomes were isolated by differential centrifugation and found to contain activating transcription factor 3 (ATF3) and Wilms Tumor 1 (WT-1) proteins detected by Western blot. These factors were found in the concentrated exosomal fraction, but not in whole urine. ATF3 was continuously present in urine exosomes of the rat models following acute injury at times earlier than the increase in serum creatinine. ATF3 was found in exosomes isolated from patients with acute kidney injury but not from patients with chronic kidney disease or controls. Urinary WT-1 was present in animal models before significant glomerular sclerosis and in 9/10 patients with focal segmental glomerulosclerosis but not in 8 controls. Our findings suggest that transcription factor ATF3 may provide a novel renal tubular cell biomarker for acute kidney injury while WT-1 may detect early podocyte injury. Measurement of urinary exosomal transcription factors may offer insight into cellular regulatory pathways.
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Affiliation(s)
- Hua Zhou
- Renal Diagnostics and Therapeutics Unit, National Institutes of Health, Bethesda, Maryland, USA
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Jia J, Ding G, Zhu J, Chen C, Liang W, Franki N, Singhal PC. Angiotensin II infusion induces nephrin expression changes and podocyte apoptosis. Am J Nephrol 2008; 28:500-7. [PMID: 18204248 DOI: 10.1159/000113538] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 11/23/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIM In in vitro studies, angiotensin (Ang) II has been demonstrated to promote podocyte apoptosis. The present study evaluates the effects of Ang II infusion in rats on podocyte nephrin expression and apoptosis and the molecular mechanisms involved in Ang II-induced proteinuria and mesangial expansion. METHODS Sprague-Dawley rats were randomly assigned to receive either normal saline or Ang II (400 ng x kg(-1) x min(-1)) by means of a mini-osmotic pump for variable time periods. Systolic blood pressure and urinary protein and albumin excretion rate measurements were carried out on days 7, 14, 21, and 28. The animals were sacrificed on days 14 and 28 and evaluated for serum creatinine, renal pathological changes, podocyte apoptosis, renal nephrin mRNA, and protein expression. RESULTS The Ang II-infused rats developed hypertension and proteinuria. On day 14, the Ang II-infused rats showed narrowing of the slit diaphragm, an increase in podocyte nephrin mRNA and protein expression, and alterations in its distribution along the foot processes. On day 28, the Ang II-infused rats demonstrated the presence of apoptotic podocytes and decreased nephrin mRNA and protein expression. There was a negative correlation between nephrin expression and the numbers of apoptotic podocytes (r = -0.63, p < 0.05). CONCLUSION These results suggest that changes in nephrin expression may play a role in the pathogenesis of Ang II-induced podocyte apoptosis.
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Affiliation(s)
- Junya Jia
- Division of Nephrology, Renmin Hospital, Wuhan University, Wuhan, China
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Ideura H, Hiromura K, Hiramatsu N, Shigehara T, Takeuchi S, Tomioka M, Sakairi T, Yamashita S, Maeshima A, Kaneko Y, Kuroiwa T, Kopp JB, Nojima Y. Angiotensin II provokes podocyte injury in murine model of HIV-associated nephropathy. Am J Physiol Renal Physiol 2007; 293:F1214-21. [PMID: 17652372 DOI: 10.1152/ajprenal.00162.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Conditional transgenic mice that express one of the human immunodeficiency virus (HIV)-1 accessory genes, vpr, selectively in podocytes using a podocin promoter and a tetracycline-inducible system develop renal injuries similar to those of patients with HIV-associated nephropathy (HIVAN). We have shown that a heminephrectomy accelerates podocyte injury, which is alleviated by angiotensin II (ANG II) type 1 receptor blocker (ARB). The current study further explores the role of ANG II in the genesis of HIVAN in this murine model. With ANG II infusion, heavy proteinuria was observed at 1 wk after the initiation of doxycycline administration to induce vpr expression in podocytes. Severe morphological and phenotypical changes in the podocytes were observed at 2 wk, together with extensive glomerulosclerosis. Norepinephrine infusion, instead of ANG II, increased the systemic blood pressure to the same level as that achieved using ANG II. However, albuminuria and glomerular injury were modest in norepinephrine-infused mice. Treatment with an ARB, olmesartan, almost completely inhibited glomerular injury. In contrast, lowering the blood pressure with a vasodilator, hydralazine, partially decreased albuminuria but did not produce any histological changes. ANG II infusion alone without doxycycline resulted in a lower level of albuminuria and minimal histological changes. These data demonstrate that excessive ANG II accelerates vpr-induced podocyte injury in a mouse model of HIVAN.
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Affiliation(s)
- Hiroshi Ideura
- Department of Medicine and Clinical Science, Gunma University Graduste School of Medicine, Maebashi, Gunma, Japan
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Naicker S, Fabian J, Naidoo S, Wadee S, Paget G, Goetsch S. Infection and glomerulonephritis. Semin Immunopathol 2007; 29:397-414. [PMID: 17846774 DOI: 10.1007/s00281-007-0088-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 08/06/2007] [Indexed: 12/26/2022]
Abstract
Glomerular injury, occurring either as primary glomerular disease or as part of a systemic disease process, is usually a result of immune-mediated mechanisms. The morphologic reaction pattern has a diverse spectrum of appearance, ranging from normal by light microscopy in minimal change disease to crescentic forms of glomerulonephritis, with conspicuous disruption of the normal glomerular morphology. The mechanisms of glomerular immune deposit formation include trapping of circulating antigen-antibody complexes and the in situ formation of immune complexes within the glomerulus. While the majority of postinfectious immune-complex-mediated glomerulonephritides are believed to result from the deposition of circulating antigen-antibody complexes, preformed outside of the kidney and secondarily deposited in the kidney, the notion of forming in situ antigen-antibody complexes to either planted antigens or to integral structural components of the glomerulus, through "cross-reacting" autoimmune reactions, is gaining popularity in a variety of forms of glomerulonephritides. Patients with HIV infection may develop a spectrum of renal pathology, the glomerular manifestations of which include both antigen-antibody complex and nonimmune-complex-mediated pathogenetic mechanisms. Similarly, patients with Streptococcal infections, Hepatitis B virus, or Hepatitis C virus infection may develop a spectrum of glomerulonephritides, which are predominantly immune-complex-mediated. Therapy for glomerular diseases due to HIV, hepatitis B, or C virus infections remains a challenge.
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Affiliation(s)
- Saraladevi Naicker
- Division of Nephrology, University of the Witwatersrand, Johannesburg Hospital, 7 York Road, Parktown, Johannesburg, Gauteng, 2193, South Africa.
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