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Ajay AK. Functional Drug Screening using Kidney Cells On-A-Chip: Advances in Disease Modeling and Development of Biomarkers. KIDNEY360 2022; 3:194-198. [PMID: 35373124 PMCID: PMC8967633 DOI: 10.34067/kid.0007172021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/13/2022] [Indexed: 01/12/2023]
Affiliation(s)
- Amrendra K. Ajay
- Division of Renal Medicine, Brigham and Women’s Hospital, Boston, Massachusetts,Department of Medicine, Harvard Medical School, Boston, Massachusetts
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2
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Mahesaniya A, Williamson CR, Keyvani Chahi A, Martin CE, Mitro AE, Lu P, New LA, Watson KL, Moorehead RA, Jones N. Sex Differences in Glomerular Protein Expression and Effects of Soy-Based Diet on Podocyte Signaling. Can J Kidney Health Dis 2022; 9:20543581221121636. [PMID: 36199279 PMCID: PMC9528100 DOI: 10.1177/20543581221121636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Indexed: 12/02/2022] Open
Abstract
Background: Kidney disease is a major public health issue arising from loss of glomerular podocyte function, and there are considerable sex differences in its prognosis. Evidence suggests a renoprotective effect of estrogen and soy diet-derived phytoestrogens, although the molecular basis for this is poorly understood. Objective: Here, we aim to assess sex differences in expression of key proteins associated with podocyte survival and determine the effects of dietary soy on glomerular and podocyte signaling. Methods: Male and female FVB mice were fed control, low (1%), and high (20%) doses of isolated soy protein (ISP) in utero and until 100 days of age. Spot urine was collected to measure proteinuria and isolated glomeruli were used to quantify activated and total levels of nephrin, Akt, and ERK1/2. To investigate protective effects of specific soy phytoestrogens, cultured podocytes were treated with or without daidzein and subject to control or high glucose as a model of podocyte injury. Results: Nephrin and Akt were elevated at baseline in glomeruli from females compared to males. Both sexes that were fed 1% and 20% ISP displayed robust increases in total glomerular Akt compared to controls, and these effects were more prominent in females. A similar trend at both doses in both sexes was observed with activated Akt and total nephrin. Notably, males exclusively showed increased phosphorylation of nephrin and extracellular signal-regulated kinase (ERK) at the 1% ISP dose; however, no overt changes in urinary albumin excretion or podocin levels were observed, suggesting that the soy diets did not impair podocyte function. Finally, in cultured male and female podocytes, daidzein treatment suppressed high glucose-induced ERK activation. Conclusions: Together, our findings reveal a putative mechanism to explain the protective influence of sex on kidney disease progression, and they provide further evidence to support a beneficial role for dietary soy in preserving glomerular function.
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Affiliation(s)
- Afreeda Mahesaniya
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | - Casey R. Williamson
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | - Ava Keyvani Chahi
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
- Present address: Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Claire E. Martin
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
- Present address: Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
| | - Alexander E. Mitro
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | - Peihua Lu
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | - Laura A. New
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
| | | | | | - Nina Jones
- Department of Molecular and Cellular Biology, University of Guelph, ON, Canada
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3
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Agarwal S, Sudhini YR, Polat OK, Reiser J, Altintas MM. Renal cell markers: lighthouses for managing renal diseases. Am J Physiol Renal Physiol 2021; 321:F715-F739. [PMID: 34632812 DOI: 10.1152/ajprenal.00182.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Kidneys, one of the vital organs in our body, are responsible for maintaining whole body homeostasis. The complexity of renal function (e.g., filtration, reabsorption, fluid and electrolyte regulation, and urine production) demands diversity not only at the level of cell types but also in their overall distribution and structural framework within the kidney. To gain an in depth molecular-level understanding of the renal system, it is imperative to discern the components of kidney and the types of cells residing in each of the subregions. Recent developments in labeling, tracing, and imaging techniques have enabled us to mark, monitor, and identify these cells in vivo with high efficiency in a minimally invasive manner. In this review, we summarize different cell types, specific markers that are uniquely associated with those cell types, and their distribution in the kidney, which altogether make kidneys so special and different. Cellular sorting based on the presence of certain proteins on the cell surface allowed for the assignment of multiple markers for each cell type. However, different studies using different techniques have found contradictions in cell type-specific markers. Thus, the term "cell marker" might be imprecise and suboptimal, leading to uncertainty when interpreting the data. Therefore, we strongly believe that there is an unmet need to define the best cell markers for a cell type. Although the compendium of renal-selective marker proteins presented in this review is a resource that may be useful to researchers, we acknowledge that the list may not be necessarily exhaustive.
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Affiliation(s)
- Shivangi Agarwal
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | | | - Onur K Polat
- Department of Internal Medicine, Rush University, Chicago, Illinois
| | - Jochen Reiser
- Department of Internal Medicine, Rush University, Chicago, Illinois
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4
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Urinary Matrix Metalloproteinase-9 and Nephrin in Idiopathic Membranous Nephropathy: A Cross-Sectional Study. DISEASE MARKERS 2021; 2021:1620545. [PMID: 34707724 PMCID: PMC8545589 DOI: 10.1155/2021/1620545] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 11/14/2020] [Accepted: 10/08/2021] [Indexed: 11/17/2022]
Abstract
Aim Idiopathic membranous nephropathy (IMN) has a varied clinical course that requires accurate prediction as a prerequisite for treatment administration. Currently, its prognosis relies on proteinuria, a clinical parameter whose onset lags behind kidney injury. Increased urinary excretion of matrix metalloproteinase-9 (MMP-9) and nephrin has been reported in a number of IMN-like glomerular diseases in which they reflected disease severity. However, little or nothing is known of the importance of these biomarkers in IMN, a major cause of adult nephrotic syndrome. To highlight their potential, we measured both biomarkers and assessed their relationships with key parameters of renal function in IMN. Methods We quantified urinary MMP-9 and nephrin in 107 biopsy-proven IMN patients and 70 healthy subjects by enzyme-linked immunosorbent assay (ELISA). We then compared biomarker levels between patients and healthy subjects and among patients with different clinical features. We also determined the relationship of each biomarker with proteinuria and the estimated glomerular filtration rate (eGFR). Results Urinary MMP-9 and nephrin were significantly higher in IMN compared to healthy controls. Unlike nephrin, MMP-9 correlated significantly with proteinuria and was significantly higher among patients with nephrotic range proteinuria. Both biomarkers were correlated with eGFR, but only MMP-9 was significantly higher in patients with eGFR less than 90 ml/min/1.73 m2. Conclusion Our findings suggest that urinary MMP-9 holds a greater potential than urinary nephrin in monitoring the severity of IMN.
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5
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Bhargava R, Lehoux S, Maeda K, Tsokos MG, Krishfield S, Ellezian L, Pollak M, Stillman IE, Cummings RD, Tsokos GC. Aberrantly glycosylated IgG elicits pathogenic signaling in podocytes and signifies lupus nephritis. JCI Insight 2021; 6:147789. [PMID: 33784256 PMCID: PMC8262331 DOI: 10.1172/jci.insight.147789] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/25/2021] [Indexed: 12/27/2022] Open
Abstract
Lupus nephritis (LN) is a serious complication occurring in 50% of patients with systemic lupus erythematosus (SLE) for which there is a lack of biomarkers, a lack of specific medications, and a lack of a clear understanding of its pathogenesis. The expression of calcium/calmodulin kinase IV (CaMK4) is increased in podocytes of patients with LN and lupus-prone mice, and its podocyte-targeted inhibition averts the development of nephritis in mice. Nephrin is a key podocyte molecule essential for the maintenance of the glomerular slit diaphragm. Here, we show that the presence of fucose on N-glycans of IgG induces, whereas the presence of galactose ameliorates, podocyte injury through CaMK4 expression. Mechanistically, CaMK4 phosphorylates NF-κB, upregulates the transcriptional repressor SNAIL, and limits the expression of nephrin. In addition, we demonstrate that increased expression of CaMK4 in biopsy specimens and in urine podocytes from people with LN is linked to active kidney disease. Our data shed light on the role of IgG glycosylation in the development of podocyte injury and propose the development of “liquid kidney biopsy” approaches to diagnose LN.
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Affiliation(s)
| | - Sylvain Lehoux
- Department of Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Beth Israel Deaconess Medical Center Glycomics Core, Boston, Massachusetts, USA
| | | | | | | | | | | | - Isaac E Stillman
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Richard D Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Beth Israel Deaconess Medical Center Glycomics Core, Boston, Massachusetts, USA
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6
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Chebotareva N, Bobkova I, Lysenko L, Moiseev S. Urinary Markers of Podocyte Dysfunction in Chronic Glomerulonephritis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1306:81-99. [PMID: 33959907 DOI: 10.1007/978-3-030-63908-2_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chronic glomerulonephritis (CGN) is a disease with a steady progressive course that involves the development of nephrosclerosis, which is especially evident in clinical courses with incidences of high proteinuria (PU). Currently, proteinuria is considered the main laboratory feature (sign) of CGN activity and progression because proteinuria is closely related to the process of tubulointerstitial fibrosis, which is correlated with the grade of renal insufficiency. The injury to podocytes, which are key components of the filtration barrier, plays a central role in proteinuria development. The detachment of podocytes from the glomerular basement membrane leading to podocytopenia is suggested to induce glomerulosclerosis and hyalinosis with obliteration of capillary loops and the progression of chronic kidney disease. Urinary markers of podocyte dysfunction could serve as useful tools while monitoring the activity and prognosis of CGN. In this chapter, the most important mechanisms of podocyte loss and urinary markers of this process are discussed.
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Affiliation(s)
- Natalia Chebotareva
- Tareev Clinic, Department of Nephrology, Sechenov First Moscow State Medical University, Moscow, Russia.
| | - Irina Bobkova
- Tareev Clinic, Department of Nephrology, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Lidia Lysenko
- Tareev Clinic, Department of Nephrology, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Sergey Moiseev
- Tareev Clinic, Department of Nephrology, Sechenov First Moscow State Medical University, Moscow, Russia
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7
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A different perspective on the filtration barrier after kidney stone formation: An immunohistochemical and biochemical study. Urolithiasis 2020; 49:201-210. [PMID: 33155094 DOI: 10.1007/s00240-020-01227-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/24/2020] [Indexed: 10/23/2022]
Abstract
The aim of this study is to investigate whether the filtration barrier is affected by experimental kidney stone formation. Thirty-two rats divided into 4 equally groups (n = 8) at random. Group I control; Group II 1% ethylene glycol; Group III 1% Ethylene glycol + 0.25% Ammonium chloride; Group IV 1% Ethylene glycol + 0.5% Ammonium chloride group. Tissues applied hematoxylin-eosin, periodic-acid-Schiff, Pizzolato's staining. Immunohistochemically stained with integrin α3β1, type IV collagen, laminin, nephrin, CD2-associated protein (CD2AP) and podocin to show the filtration barrier structure. The TUNEL method was used for apoptosis. The amount of calcium, magnesium, creatinine and uric acid in urine and blood samples, also urine microprotein determined. Stones were formed in all experimental groups. Urine calcium, creatinine, uric acid levels decreased, magnesium levels were not changed. No statistically significant change was observed in blood serum results and TUNEL analysis. Immunohistochemical results showed an increase in nephrin, podocin, CD2AP, laminin and a decrease in integrin α3β1 and type IV collagen. Consequently, there is an increase in the expression densities of the proteins incorporated in the structure to prevent loss of functionality in the cellular part supporting the structure against a weakening of the basement membrane structure in the glomerular structure in which urine is filtered.
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8
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Liu W, Gao C, Liu Z, Dai H, Feng Z, Dong Z, Zheng Y, Gao Y, Tian X, Liu B. Idiopathic Membranous Nephropathy: Glomerular Pathological Pattern Caused by Extrarenal Immunity Activity. Front Immunol 2020; 11:1846. [PMID: 33042109 PMCID: PMC7524879 DOI: 10.3389/fimmu.2020.01846] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
Idiopathic membranous nephropathy (IMN) is a pathological pattern of glomerular damage caused by an autoimmune response. Immune complex deposition, thickness of glomerular basement membrane, and changes in the podocyte morphology are responsible for the development of proteinuria, which is caused by the targeted binding of auto-antibodies to podocytes. Several auto-antigens have recently been identified in IMN, including M-type receptor for secretory phospholipase A2 (PLA2R1), thrombospondin type-1 domain-containing 7A (THSD7A), and neural epidermal growth factor-like 1 protein (NELL-1). The measurement of peripheral circulating antibodies has become an important clinical reference index. However, some clinical features of IMN remain elusive and need to be further investigated, such as the autoimmunity initiation, IgG4 predominance, spontaneous remission, and the unique glomerular lesion. As these unresolved issues are closely related to clinical practice, we have proposed a hypothetical pathogenesis model of IMN. Induced by environmental stimuli or other causes, the PLA2R1 antigen and/or THSD7A antigen exposed to extrarenal tissues, such as lungs, then produce the auto-antibodies that target and cause damage to the podocytes in circulation. In this review, we highlighted the potential association between environmental stimuli, immune activity, and glomerular lesions, the underlying basis for spontaneous immune and proteinuria remission.
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Affiliation(s)
- Wenbin Liu
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Chang Gao
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Zhiyuan Liu
- Basic Medical College, Taishan Medical University, Tai'an, China
| | - Haoran Dai
- Beijing Chinese Medicine Hospital PingGu Hospital, Beijing, China
| | - Zhendong Feng
- Shunyi Branch, Beijing Hospital of Traditional Chinese Medicine, Beijing, China
| | - Zhaocheng Dong
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Yang Zheng
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Yu Gao
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
| | - Xuefei Tian
- Section of Nephrology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
| | - Baoli Liu
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing, China
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9
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Pisarek-Horowitz A, Fan X, Kumar S, Rasouly HM, Sharma R, Chen H, Coser K, Bluette CT, Hirenallur-Shanthappa D, Anderson SR, Yang H, Beck LH, Bonegio RG, Henderson JM, Berasi SP, Salant DJ, Lu W. Loss of Roundabout Guidance Receptor 2 (Robo2) in Podocytes Protects Adult Mice from Glomerular Injury by Maintaining Podocyte Foot Process Structure. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:799-816. [PMID: 32220420 PMCID: PMC7217334 DOI: 10.1016/j.ajpath.2019.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 11/24/2019] [Accepted: 12/17/2019] [Indexed: 02/06/2023]
Abstract
Roundabout guidance receptor 2 (ROBO2) plays an important role during early kidney development. ROBO2 is expressed in podocytes, inhibits nephrin-induced actin polymerization, down-regulates nonmuscle myosin IIA activity, and destabilizes kidney podocyte adhesion. However, the role of ROBO2 during kidney injury, particularly in mature podocytes, is not known. Herein, we report that loss of ROBO2 in podocytes [Robo2 conditional knockout (cKO) mouse] is protective from glomerular injuries. Ultrastructural analysis reveals that Robo2 cKO mice display less foot process effacement and better-preserved slit-diaphragm density compared with wild-type littermates injured by either protamine sulfate or nephrotoxic serum (NTS). The Robo2 cKO mice also develop less proteinuria after NTS injury. Further studies reveal that ROBO2 expression in podocytes is up-regulated after glomerular injury because its expression levels are higher in the glomeruli of NTS injured mice and passive Heymann membranous nephropathy rats. Moreover, the amount of ROBO2 in the glomeruli is also elevated in patients with membranous nephropathy. Finally, overexpression of ROBO2 in cultured mouse podocytes compromises cell adhesion. Taken together, these findings suggest that kidney injury increases glomerular ROBO2 expression that might compromise podocyte adhesion and, thus, loss of Robo2 in podocytes could protect from glomerular injury by enhancing podocyte adhesion that helps maintain foot process structure. Our findings also suggest that ROBO2 is a therapeutic target for podocyte injury and podocytopathy.
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Affiliation(s)
- Anna Pisarek-Horowitz
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Xueping Fan
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Sudhir Kumar
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Hila M Rasouly
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Richa Sharma
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Hui Chen
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Kathryn Coser
- Centers for Therapeutic Innovation, Pfizer Inc., Cambridge, Massachusetts
| | | | | | - Sarah R Anderson
- Global Pathology, Drug Safety Research and Development, Pfizer Inc., Groton, Connecticut
| | - Hongying Yang
- Centers for Therapeutic Innovation, Pfizer Inc., Cambridge, Massachusetts
| | - Laurence H Beck
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Ramon G Bonegio
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Joel M Henderson
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Stephen P Berasi
- Centers for Therapeutic Innovation, Pfizer Inc., Cambridge, Massachusetts
| | - David J Salant
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts; Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
| | - Weining Lu
- Renal Section, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts; Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts.
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10
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Pierre TH, Reynolds AS, Seise I, Pilz Z, McHale BJ, Gato WE. Evaluation of renal markers of T1D in Sprague-Dawley exposed to 2-aminoanthracene. ENVIRONMENTAL TOXICOLOGY 2020; 35:203-212. [PMID: 31714650 DOI: 10.1002/tox.22857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/03/2019] [Accepted: 09/15/2019] [Indexed: 06/10/2023]
Abstract
The incidence of type 1 diabetes (T1D) and its associated risks of chronic kidney disease or end-stage renal disease development are on the rise. T1D is an autoimmune disease in which insulin-producing beta cells are destroyed. Increased incidence of T1D has been suggested to be a result of environmental factors such as exposure to polycyclic aromatic hydrocarbons (PAHs). 2-aminoanthracene (2AA) is a PAH that has been associated with the onset of early diabetic symptoms. This study was conducted to assess if 2AA dietary ingestion would induce T1D renal injuries. To accomplish study goals, Sprague-Dawley rats were assigned into three 2AA dietary (0, 50, and 100 mg/kg-2AA) ingestion groups for 12 weeks. Animals were evaluated for various morphometric indices, clinical markers, and gene expression. The rats in the 100 mg/kg group lost 5% less weight than the other treatment groups and converted roughly 3% more of their food intake into body mass. Renal histopathology indicated no significant difference between groups. The kidney weight per bodyweight of the 100 mg/kg treatment group was 30.1% greater than the control group. Creatinine concentration of the 100 mg/kg group was 46.2% greater than the control group. Serum glucose levels were significantly elevated in rats exposed to 2AA. On the contrary, serum albumin concentration was significantly reduced in 2AA-treated rats. T1D and genetic markers of renal injury such as FABP1, SPP1, IL-1B, and IL-7 were elevated in treated groups. These results suggest that 2AA may induce the early diabetic renal injuries.
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Affiliation(s)
- Tanya H Pierre
- Department of Biology and Chemistry, Agnes Scott College, Decatur, Georgia
| | - Ashley S Reynolds
- Department of Biology and Chemistry, King University, Bristol, Tennessee
| | - Isaiah Seise
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia
| | - Zach Pilz
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia
| | - Brittany J McHale
- Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, Georgia
| | - Worlanyo E Gato
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia
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11
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Nakhoul N, Thawko T, Farber E, Dahan I, Tadmor H, Nakhoul R, Hanut A, Salameh G, Shagrawy I, Nakhoul F. The Therapeutic Effect of Active Vitamin D Supplementation in Preventing the Progression of Diabetic Nephropathy in a Diabetic Mouse Model. J Diabetes Res 2020; 2020:7907605. [PMID: 33294462 PMCID: PMC7714593 DOI: 10.1155/2020/7907605] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes and is the leading cause of end-stage renal disease (ESRD) and replacement therapy worldwide. Vitamin D levels in DN patients are very low due to the decrease in the synthesis and activity of 1-α hydroxylase in the proximal tubule cells and decrease in the vitamin D receptor abundance. To date, few studies have shown the antioxidant effects of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] on hyperglycemia-induced renal injury. The selective activator of the vitamin D receptor, paricalcitol, reduces proteinuria and slows the progression of kidney injury. The precise mechanism through which vitamin D affects diabetic status and provides kidney protection remains to be determined. METHODS Diabetes mellitus (DM) was induced in 94 8-week-old DBA/2J mice by intraperitoneal injection of streptozotocin (STZ). DM mice were randomly divided into receiving vehicle or treatment with paricalcitol, the active vitamin D analog, 1 week after DM induction or paricalcitol treatment 3 weeks after DM induction. An additional control group of healthy wild-type mice was not treated. Urine albumin, blood urea nitrogen, and creatinine levels were measured before and at the end of the paricalcitol treatment. Periodic acid-Schiff, immunohistochemistry staining, and western blot of the renal tissues of vitamin D receptor, villin, nephrin, and podocin expressions, were analyzed. RESULTS Paricalcitol treatment restored villin, nephrin, and podocin protein levels that were downregulated upon DM induction, and reduced fibronectin protein level. Vitamin D receptor activation by paricalcitol may reduce proteinuria of DN in mice and alleviate high-glucose-induced injury of kidney podocytes by regulating the key molecules such nephrin-podocin. CONCLUSIONS Paricalcitol treatment was associated with improved structural changes in type 1 diabetic mice including upregulation of vitamin D receptor expression, and decreased fibrosis markers such as fibronectin. These effects may contribute to the consistent benefit of vitamin D analog to slow the deterioration in glomerular function and reduce the risk of ESRD in patients with type 1 and 2 diabetes mellitus. Our results suggest that additional use of paricalcitol may be beneficial in treating patients with diabetes under standard therapeutic strategies.
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Affiliation(s)
- Nakhoul Nakhoul
- The Diabetes & Metabolism Lab, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
- Ophthalmology, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
| | - Tina Thawko
- The Diabetes & Metabolism Lab, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
| | - Evgeny Farber
- Nephrology & Hypertension Division, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
| | - Inbal Dahan
- The Diabetes & Metabolism Lab, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
| | - Hagar Tadmor
- The Diabetes & Metabolism Lab, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
| | | | - Anaam Hanut
- Nephrology & Hypertension Division, Bar-Ilan University, Ramat Gan, Israel
| | - Ghasan Salameh
- The Diabetes & Metabolism Lab, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
| | - Ibrahim Shagrawy
- Pathology Division, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
| | - Farid Nakhoul
- The Diabetes & Metabolism Lab, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
- Nephrology & Hypertension Division, Baruch Padeh Poriya Medical Center, Lower Galilee, Israel
- Azrieli Faculty of Medicine, Bar-Ilan University, Ramat Gan, Israel
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12
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Andrighetto S, Leventhal J, Zaza G, Cravedi P. Complement and Complement Targeting Therapies in Glomerular Diseases. Int J Mol Sci 2019; 20:ijms20246336. [PMID: 31888179 PMCID: PMC6940904 DOI: 10.3390/ijms20246336] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/10/2019] [Indexed: 01/02/2023] Open
Abstract
The complement cascade is part of the innate immune system whose actions protect hosts from pathogens. Recent research shows complement involvement in a wide spectrum of renal disease pathogenesis including antibody-related glomerulopathies and non-antibody-mediated kidney diseases, such as C3 glomerular disease, atypical hemolytic uremic syndrome, and focal segmental glomerulosclerosis. A pivotal role in renal pathogenesis makes targeting complement activation an attractive therapeutic strategy. Over the last decade, a growing number of anti-complement agents have been developed; some are approved for clinical use and many others are in the pipeline. Herein, we review the pathways of complement activation and regulation, illustrate its role instigating or amplifying glomerular injury, and discuss the most promising novel complement-targeting therapies.
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Affiliation(s)
- Sofia Andrighetto
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, 1 Levy Place, New York, NY 10029, USA; (S.A.); (J.L.)
- Renal Unit, Department of Medicine, University/Hospital of Verona, 37126 Verona, Italy;
| | - Jeremy Leventhal
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, 1 Levy Place, New York, NY 10029, USA; (S.A.); (J.L.)
| | - Gianluigi Zaza
- Renal Unit, Department of Medicine, University/Hospital of Verona, 37126 Verona, Italy;
| | - Paolo Cravedi
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, 1 Levy Place, New York, NY 10029, USA; (S.A.); (J.L.)
- Correspondence: ; Tel.: +1-212-241-3349; Fax: +1-212-987-0389
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13
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Petrosyan A, Cravedi P, Villani V, Angeletti A, Manrique J, Renieri A, De Filippo RE, Perin L, Da Sacco S. A glomerulus-on-a-chip to recapitulate the human glomerular filtration barrier. Nat Commun 2019; 10:3656. [PMID: 31409793 PMCID: PMC6692336 DOI: 10.1038/s41467-019-11577-z] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 07/23/2019] [Indexed: 12/24/2022] Open
Abstract
In this work we model the glomerular filtration barrier, the structure responsible for filtering the blood and preventing the loss of proteins, using human podocytes and glomerular endothelial cells seeded into microfluidic chips. In long-term cultures, cells maintain their morphology, form capillary-like structures and express slit diaphragm proteins. This system recapitulates functions and structure of the glomerulus, including permselectivity. When exposed to sera from patients with anti-podocyte autoantibodies, the chips show albuminuria proportional to patients' proteinuria, phenomenon not observed with sera from healthy controls or individuals with primary podocyte defects. We also show its applicability for renal disease modeling and drug testing. A total of 2000 independent chips were analyzed, supporting high reproducibility and validation of the system for high-throughput screening of therapeutic compounds. The study of the patho-physiology of the glomerulus and identification of therapeutic targets are also feasible using this chip.
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Affiliation(s)
- Astgik Petrosyan
- GOFARR Laboratory for Organ Regenerative Research and Cell Therapeutics in Urology, Saban Research Institute, Division of Urology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Paolo Cravedi
- Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Valentina Villani
- GOFARR Laboratory for Organ Regenerative Research and Cell Therapeutics in Urology, Saban Research Institute, Division of Urology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Andrea Angeletti
- Department of Experimental, Diagnostic and Specialty Medicine, Nephrology, Dialysis and Renal Transplant Unit, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Joaquin Manrique
- Nephrology Service, Complejo Hospitalario de Navarra, Pamplona, Spain
| | | | - Roger E De Filippo
- GOFARR Laboratory for Organ Regenerative Research and Cell Therapeutics in Urology, Saban Research Institute, Division of Urology, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Laura Perin
- GOFARR Laboratory for Organ Regenerative Research and Cell Therapeutics in Urology, Saban Research Institute, Division of Urology, Children's Hospital Los Angeles, Los Angeles, CA, USA. .,Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
| | - Stefano Da Sacco
- GOFARR Laboratory for Organ Regenerative Research and Cell Therapeutics in Urology, Saban Research Institute, Division of Urology, Children's Hospital Los Angeles, Los Angeles, CA, USA. .,Department of Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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14
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Niculovic KM, Blume L, Wedekind H, Kats E, Albers I, Groos S, Abeln M, Schmitz J, Beuke E, Bräsen JH, Melk A, Schiffer M, Weinhold B, Münster-Kühnel AK. Podocyte-Specific Sialylation-Deficient Mice Serve as a Model for Human FSGS. J Am Soc Nephrol 2019; 30:1021-1035. [PMID: 31040189 DOI: 10.1681/asn.2018090951] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 02/26/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The etiology of steroid-resistant nephrotic syndrome, which manifests as FSGS, is not completely understood. Aberrant glycosylation is an often underestimated factor for pathologic processes, and structural changes in the glomerular endothelial glycocalyx have been correlated with models of nephrotic syndrome. Glycans are frequently capped by sialic acid (Sia), and sialylation's crucial role for kidney function is well known. Human podocytes are highly sialylated; however, sialylation's role in podocyte homeostasis remains unclear. METHODS We generated a podocyte-specific sialylation-deficient mouse model (PCmas-/- ) by targeting CMP-Sia synthetase, and used histologic and ultrastructural analysis to decipher the phenotype. We applied CRISPR/Cas9 technology to generate immortalized sialylation-deficient podocytes (asialo-podocytes) for functional studies. RESULTS Progressive loss of sialylation in PCmas-/- mice resulted in onset of proteinuria around postnatal day 28, accompanied by foot process effacement and loss of slit diaphragms. Podocyte injury led to severe glomerular defects, including expanded capillary lumen, mesangial hypercellularity, synechiae formation, and podocyte loss. In vivo, loss of sialylation resulted in mislocalization of slit diaphragm components, whereas podocalyxin localization was preserved. In vitro, asialo-podocytes were viable, able to proliferate and differentiate, but showed impaired adhesion to collagen IV. CONCLUSIONS Loss of cell-surface sialylation in mice resulted in disturbance of podocyte homeostasis and FSGS development. Impaired podocyte adhesion to the glomerular basement membrane most likely contributed to disease development. Our data support the notion that loss of sialylation might be part of the complex process causing FSGS. Sialylation, such as through a Sia supplementation therapy, might provide a new therapeutic strategy to cure or delay FSGS and potentially other glomerulopathies.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Esther Beuke
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany; and
| | - Jan H Bräsen
- Nephropathology Unit, Institute of Pathology, and
| | - Anette Melk
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany; and
| | - Mario Schiffer
- Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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15
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Verma R, Venkatareddy M, Kalinowski A, Li T, Kukla J, Mollin A, Cara-Fuentes G, Patel SR, Garg P. Nephrin is necessary for podocyte recovery following injury in an adult mature glomerulus. PLoS One 2018; 13:e0198013. [PMID: 29924795 PMCID: PMC6010211 DOI: 10.1371/journal.pone.0198013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 05/12/2018] [Indexed: 11/28/2022] Open
Abstract
Nephrin (Nphs1) is an adhesion protein that is expressed at the podocyte intercellular junction in the glomerulus. Nphs1 mutations in humans or deletion in animal genetic models results in a developmental failure of foot process formation. A number of studies have shown decrease in expression of nephrin in various proteinuric kidney diseases as well as in animal models of glomerular disease. Decrease in nephrin expression has been suggested to precede podocyte loss and linked to the progression of kidney disease. Whether the decrease in expression of nephrin is related to loss of podocytes or lead to podocyte detachment is unclear. To answer this central question we generated an inducible model of nephrin deletion (Nphs1Tam-Cre) in order to lower nephrin expression in healthy adult mice. Following tamoxifen-induction there was a 75% decrease in nephrin expression by 14 days. The Nphs1Tam-Cre mice had normal foot process ultrastructure and intact filtration barriers up to 4-6 weeks post-induction. Despite the loss of nephrin expression, the podocyte number and density remained unchanged during the initial period. Unexpectedly, nephrin expression, albeit at low levels persisted at the slit diaphragm up to 16-20 weeks post-tamoxifen induction. The mice became progressively proteinuric with glomerular hypertrophy and scarring reminiscent of focal and segmental glomerulosclerosis at 20 weeks. Four week-old Nphs1 knockout mice subjected to protamine sulfate model of podocyte injury demonstrated failure to recover from foot process effacement following heparin sulfate. Similarly, Nphs1 knockout mice failed to recover following nephrotoxic serum (NTS) with persistence of proteinuria and foot process effacement. Our results suggest that as in development, nephrin is necessary for maintenance of a healthy glomerular filter. In contrast to the developmental phenotype, lowering nephrin expression in a mature glomerulus resulted in a slowly progressive disease that histologically resembles FSGS a disease linked closely with podocyte depletion. Podocytes with low levels of nephrin expression are both susceptible and unable to recover following perturbation. Our results suggest that decreased nephrin expression independent of podocyte loss occurring as an early event in proteinuric kidney diseases might play a role in disease progression.
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Affiliation(s)
- Rakesh Verma
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Madhusudan Venkatareddy
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Anne Kalinowski
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Theodore Li
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Joanna Kukla
- Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | | | - Gabriel Cara-Fuentes
- Division of Pediatric Nephrology, Motts Children Hospital, Ann Arbor, Michigan, United States of America
| | - Sanjeevkumar R. Patel
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
- Veterans Administration, VAMC, Ann Arbor, Michigan, United States of America
| | - Puneet Garg
- Division of Nephrology, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
- Veterans Administration, VAMC, Ann Arbor, Michigan, United States of America
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16
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Hoxha E, von Haxthausen F, Wiech T, Stahl RAK. Membranous nephropathy-one morphologic pattern with different diseases. Pflugers Arch 2017; 469:989-996. [PMID: 28555350 DOI: 10.1007/s00424-017-2000-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/14/2017] [Accepted: 05/16/2017] [Indexed: 01/05/2023]
Abstract
Since the discovery of the phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type-1 domain-containing 7A (THSD7A) as endogenous antigens involved in the development of membranous nephropathy (MN) in over 80% of adult patients, substantial progress in the diagnosis, prognosis, and therapy of MN has been made. In most cases of patients with MN, it is now possible to specifically define the responsible pathogenic mechanisms of disease and make a diagnosis even without a renal biopsy. Moreover, the presence of antibodies in the blood and the detection of the antigens in renal biopsies allow the definite diagnosis without the morphologic uncertainties, which now still apply for only about 20% of all renal biopsies showing MN. The discovery that the expression of THSD7A in malignant tumors might serve as the site of primary antigen recognition for the immune system to start MN might lead to a better understanding of not only tumor-associated MN, which accounts for up to 10% of all patients with MN, but also of the pathomechanisms relevant for MN development in general.
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Affiliation(s)
- Elion Hoxha
- III. Medizinische Klinik, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.,SFB 1192, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | | | - Thorsten Wiech
- SFB 1192, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Sektion Nephropathologie, Institut für Pathologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Rolf A K Stahl
- SFB 1192, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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17
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Verma R, Venkatareddy M, Kalinowski A, Patel SR, Garg P. Integrin Ligation Results in Nephrin Tyrosine Phosphorylation In Vitro. PLoS One 2016; 11:e0148906. [PMID: 26848974 PMCID: PMC4743922 DOI: 10.1371/journal.pone.0148906] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 01/24/2016] [Indexed: 11/19/2022] Open
Abstract
Nephrin is expressed at the basolateral aspect of podocytes and is an important signaling protein at the glomerular slit diaphragm. In vitro studies have demonstrated that Nephrin phosphorylation-dependent signaling is able to assemble a protein complex that is able to polymerize actin. However, proximal signaling events that result in nephrin tyrosine phosphorylation are not well understood. Nephrin deletion in mice and human nephrin mutations result in developmental failure of the podocyte intercellular junction resutling in proteinuria. This has been presumed to be due to a failure to respond to an external polarized cue in the absence of nephrin or a failure to transduce an outside-in signal in patients with nephrin mutations. The nephrin extracellular domain binds to itself or neph1 across the foot process intercellular junction. Nephrin is tyrosine phosphorylation-silent in healthy glomeruli when presumably the nephrin extracellular domain is in an engaged state. These observations raise the possibility of an alternate proximal signaling mechanism that might be responsible for nephrin tyrosine phosphorylation. Here we present data showing that integrin engagement at the basal aspect of cultured podocytes results in nephrin tyrosine phosphorylation. This is abrogated by incubating podocytes with an antibody that prevents integrin β1 ligation and activation in response to binding to extracellular matrix. Furthermore, nephrin tyrosine phosphorylation was observed in podocytes expressing a membrane-targeted nephrin construct that lacks the extracellular domain. We propose, integrin-activation based signaling might be responsible for nephrin phosphorylation rather than engagment of the nephrin extracellular domain by a ligand.
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Affiliation(s)
- Rakesh Verma
- Division of Nephroloigy, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Madhusudan Venkatareddy
- Division of Nephroloigy, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Anne Kalinowski
- Division of Nephroloigy, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Sanjeevkumar R. Patel
- Division of Nephroloigy, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
| | - Puneet Garg
- Division of Nephroloigy, Department of Internal Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, United States of America
- * E-mail:
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18
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Li TT, Zhang XH, Jing JF, Li X, Yang XQ, Zhu FH, Tang W, Zuo JP. Artemisinin analogue SM934 ameliorates the proteinuria and renal fibrosis in rat experimental membranous nephropathy. Acta Pharmacol Sin 2015; 36:188-99. [PMID: 25619396 DOI: 10.1038/aps.2014.134] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/27/2014] [Indexed: 12/14/2022] Open
Abstract
AIM SM934 is a novel water-soluble artemisinin derivative with immunoregulatory activities that has been used to treat murine lupus nephritis. In the current study, we investigated the effects of SM934 on rat experimental membranous nephropathy. METHODS Passive Heymann nephritis (PHN) was induced in SD rats by intraperitoneal injection of anti-Fx1A serum. The rats were orally administered SM934 (12.5 and 25 mg·kg(-1)·d(-1)) or prednisolone (5 mg·kg(-1)·d(-1)) for 28 d. Blood and urine sample, and kidney tissue were collected for analyses. Human complement C3a-induced injury of HK-2 cells was used for in vitro experiments. RESULTS Treatment of PHN rats with SM934 or prednisolone attenuated the progression of glomerulonephritis and renal fibrosis, as evidenced by the reduced level of proteinuria and circulating antibodies, as well as by the reduced immune complex deposition, reversed podocyte injuries, and attenuated tubulointerstitial fibrosis in the kidneys. Furthermore, the two drugs suppressed TGF-β1 expression and Smad2/3 phosphorylation, and increased Smad7 expression in the kidneys. The two doses of SM934 produced almost identical therapeutic effects on PHN rats. Pretreatment with SM934 or a C3a receptor antagonist blocked the C3a-induced epithelial-mesenchymal transition in HK-2 cells in vitro. CONCLUSION SM934 ameliorates kidney injury and attenuates the tubulointerstitial fibrosis in PHN rats by down-regulation of the TGF-β1/Smad signaling pathway.
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19
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Kapodistria K, Tsilibary EP, Politis P, Moustardas P, Charonis A, Kitsiou P. Nephrin, a transmembrane protein, is involved in pancreatic beta-cell survival signaling. Mol Cell Endocrinol 2015; 400:112-28. [PMID: 25448064 DOI: 10.1016/j.mce.2014.11.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 10/15/2014] [Accepted: 11/03/2014] [Indexed: 01/15/2023]
Abstract
Nephrin, a cell surface signaling receptor, regulates podocyte function in health and disease. We study the role of nephrin in β-cell survival signaling. We report that in mouse islet β-cells and the mouse pancreatic beta-cell line (βTC-6 cells) nephrin is associated and partly co-localized with PI3-kinase. Incubation of cells with functional anti-nephrin antibodies induced nephrin clustering at the plasma membrane, nephrin phosphorylation and recruitment of PI3-kinase to nephrin thus resulting in increased PI3K-dependent Akt phosphorylation and augmented phosphorylation/inhibition of pro-apoptotic Bad and FoxO. Nephrin silencing abolished Akt activation and increased susceptibility of cells to apoptosis. High glucose impaired nephrin signaling, increased nephrin internalization and up-regulated PKCα expression. Interestingly, a marked decrease in nephrin expression and phosphorylated Akt was observed in pancreatic islets of db/db lepr-/- diabetic mice. Our findings revealed that nephrin is involved in β-cell survival and suggest that glucose-induced changes in nephrin signaling may contribute to gradual pancreatic β-cell loss in type 2 diabetes.
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Affiliation(s)
- Katerina Kapodistria
- Institute of Biosciences and Applications, National Centre for Scientific Research, N.C.S.R. "Demokritos", Terma Patriarchou Grigoriou & Neapoleos, 15310 Agia Paraskevi, Attiki, Greece
| | - Effie-Photini Tsilibary
- Institute of Biosciences and Applications, National Centre for Scientific Research, N.C.S.R. "Demokritos", Terma Patriarchou Grigoriou & Neapoleos, 15310 Agia Paraskevi, Attiki, Greece
| | - Panagiotis Politis
- Center for Basic Research, Biomedical Research Foundation Academy of Athens (BRFAA), 4 Soranou Ephessiou, Athens 115 27, Greece
| | - Petros Moustardas
- Center for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation Academy of Athens (BRFAA), 4 Soranou Ephessiou, Athens 115 27, Greece
| | - Aristidis Charonis
- Center for Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation Academy of Athens (BRFAA), 4 Soranou Ephessiou, Athens 115 27, Greece
| | - Paraskevi Kitsiou
- Institute of Biosciences and Applications, National Centre for Scientific Research, N.C.S.R. "Demokritos", Terma Patriarchou Grigoriou & Neapoleos, 15310 Agia Paraskevi, Attiki, Greece.
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20
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Mathern DR, Heeger PS. Molecules Great and Small: The Complement System. Clin J Am Soc Nephrol 2015; 10:1636-50. [PMID: 25568220 DOI: 10.2215/cjn.06230614] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The complement cascade, traditionally considered an effector arm of innate immunity required for host defense against pathogens, is now recognized as a crucial pathogenic mediator of various kidney diseases. Complement components produced by the liver and circulating in the plasma undergo activation through the classical and/or mannose-binding lectin pathways to mediate anti-HLA antibody-initiated kidney transplant rejection and autoantibody-initiated GN, the latter including membranous glomerulopathy, antiglomerular basement membrane disease, and lupus nephritis. Inherited and/or acquired abnormalities of complement regulators, which requisitely limit restraint on alternative pathway complement activation, contribute to the pathogenesis of the C3 nephropathies and atypical hemolytic uremic syndrome. Increasing evidence links complement produced by endothelial cells and/or tubular cells to the pathogenesis of kidney ischemia-reperfusion injury and progressive kidney fibrosis. Data emerging since the mid-2000s additionally show that immune cells, including T cells and antigen-presenting cells, produce alternative pathway complement components during cognate interactions. The subsequent local complement activation yields production of the anaphylatoxins C3a and C5a, which bind to their respective receptors (C3aR and C5aR) on both partners to augment effector T-cell proliferation and survival, while simultaneously inhibiting regulatory T-cell induction and function. This immune cell-derived complement enhances pathogenic alloreactive T-cell immunity that results in transplant rejection and likely contributes to the pathogenesis of other T cell-mediated kidney diseases. C5a/C5aR ligations on neutrophils have additionally been shown to contribute to vascular inflammation in models of ANCA-mediated renal vasculitis. New translational immunology efforts along with the development of pharmacologic agents that block human complement components and receptors now permit testing of the intriguing concept that targeting complement in patients with an assortment of kidney diseases has the potential to abrogate disease progression and improve patient health.
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Affiliation(s)
- Douglas R Mathern
- Translational Transplant Research Center, Department of Medicine, Recanati Miller Transplant Institute, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Peter S Heeger
- Translational Transplant Research Center, Department of Medicine, Recanati Miller Transplant Institute, Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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21
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Lai WL, Yeh TH, Chen PM, Chan CK, Chiang WC, Chen YM, Wu KD, Tsai TJ. Membranous nephropathy: a review on the pathogenesis, diagnosis, and treatment. J Formos Med Assoc 2015; 114:102-11. [PMID: 25558821 DOI: 10.1016/j.jfma.2014.11.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 11/07/2014] [Accepted: 11/12/2014] [Indexed: 11/25/2022] Open
Abstract
In adults, membranous nephropathy (MN) is a major cause of nephrotic syndrome. However, the etiology of approximately 75% of MN cases is idiopathic. Secondary causes of MN are autoimmune diseases, infection, drugs, and malignancy. The pathogenesis of MN involves formation of immune complex in subepithelial sites, but the definite mechanism is still unknown. There are three hypotheses about the formation of immune complex, including preformed immune complex, in situ immune-complex formation, and autoantibody against podocyte membrane antigen. The formation of immune complex initiates complement activation, which subsequently leads to glomerular damage. Recently, the antiphospholipase A2 receptor antibody was found to be associated with idiopathic MN. This finding may be useful in the diagnosis and prognosis of MN. The current treatment includes best supportive care, which consists of the use of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, lipid-lowering agents, and optimal control of blood pressure. Immunosuppressive agents should be used for patients who suffer from refractory proteinuria or complications associated with nephrotic syndrome. Existing evidence supports the use of a combination of steroid and alkylating agents. This article reviews the epidemiology, pathogenesis, diagnosis, and the treatment of MN.
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Affiliation(s)
- Wei Ling Lai
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Ting Hao Yeh
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Ping Min Chen
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Chieh Kai Chan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Wen Chih Chiang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
| | - Yung Ming Chen
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Kwan Dun Wu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Tun Jun Tsai
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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22
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Neal CR. Podocytes … What's Under Yours? (Podocytes and Foot Processes and How They Change in Nephropathy). Front Endocrinol (Lausanne) 2015; 6:9. [PMID: 25755650 PMCID: PMC4337384 DOI: 10.3389/fendo.2015.00009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 01/15/2015] [Indexed: 12/25/2022] Open
Abstract
Most of the described structures of podocytes in health and disease have been inferred from light and electron microscopic studies of rodent models. The variation in filtration barrier features is measured on micrographs, the aim being statistical significance. This is the technical campaign waged against kidney disease but this approach can be misleading. The signaling cascades and connectivity of the podocyte and foot processes (FPs) are inferred from in vitro studies that at best blurr the reality of the in vivo state. This review will outline actin signaling connectivity and the key differences in the structural and functional domains squeezed into the FPs and the relationship of these domains to other parts of the podocyte. It covers the changes in podocytes during nephropathy concentrating on FP and finally proposes an alternative interpretation of FP ultrastructure derived from articles published over the last 60 years.
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Affiliation(s)
- Chris R. Neal
- Bristol Renal, University of Bristol, Bristol, UK
- *Correspondence: Chris R. Neal, Bristol Renal, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK e-mail:
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23
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Abstract
Membranous nephropathy (MN) describes a histopathologic pattern of injury marked by glomerular subepithelial immune deposits and collectively represents one of the most common causes of adult nephrotic syndrome. Studies in Heymann nephritis, an experimental model of MN, have established a paradigm in which these deposits locally activate complement to cause podocyte injury, culminating in cytoskeletal reorganization, loss of slit diaphragms, and proteinuria. There is much circumstantial evidence for a prominent role of complement in human MN because C3 and C5b-9 are found consistently within immune deposits. Secondary MN often shows the additional presence of C1q, implicating the classic pathway of complement activation. Primary MN, however, is IgG4-predominant and IgG4 is considered incapable of binding C1q and activating the complement pathway. Recent studies have identified the M-type phospholipase A2 receptor (PLA2R) as the major target antigen in primary MN. Early evidence hints that IgG4 anti-PLA2R autoantibodies can bind mannan-binding lectin and activate the lectin complement pathway. The identification of anti-PLA2R antibodies as likely participants in the pathogenesis of disease will allow focused investigation into the role of complement in MN. Definitive therapy for MN is immunosuppression, although future therapeutic agents that specifically target complement activation may represent an effective temporizing measure to forestall further glomerular injury.
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Affiliation(s)
- Hong Ma
- Department of Medicine, Renal Section, Boston University School of Medicine
| | - Dana G. Sandor
- Department of Medicine, Renal Section, Boston University School of Medicine
| | - Laurence H. Beck
- Department of Medicine, Renal Section, Boston University School of Medicine
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24
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Upregulation of c-mip is closely related to podocyte dysfunction in membranous nephropathy. Kidney Int 2013; 83:414-25. [PMID: 23302718 DOI: 10.1038/ki.2012.426] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Membranous nephropathy is a glomerular disease typified by a nephrotic syndrome without infiltration of inflammatory cells or proliferation of resident cells. Although the cause of the disease is unknown, the primary pathology involves the generation of autoantibodies against antigen targets on the surface of podocytes. The mechanisms of nephrotic proteinuria, which reflect a profound podocyte dysfunction, remain unclear. We previously found a new gene, c-mip (c-maf-inducing protein), that was associated with the pathophysiology of idiopathic nephrotic syndrome. Here we found that c-mip was not detected in the glomeruli of rats with passive-type Heymann nephritis given a single dose of anti-megalin polyclonal antibody, yet immune complexes were readily present, but without triggering of proteinuria. Rats reinjected with anti-megalin develop heavy proteinuria a few days later, concomitant with c-mip overproduction in podocytes. This overexpression was associated with the downregulation of synaptopodin in patients with membranous nephropathy, rats with passive Heymann nephritis, and c-mip transgenic mice, while the abundance of death-associated protein kinase and integrin-linked kinase was increased. Cyclosporine treatment significantly reduced proteinuria in rats with passive Heymann nephritis, concomitant with downregulation of c-mip in podocytes. Thus, c-mip has an active role in the podocyte disorders of membranous nephropathy.
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Cyprinus carpio Decoction Improves Nutrition and Immunity and Reduces Proteinuria through Nephrin and CD2AP Expressions in Rats with Adriamycin-Induced Nephropathy. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:237482. [PMID: 22675377 PMCID: PMC3362917 DOI: 10.1155/2012/237482] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 03/03/2012] [Accepted: 03/19/2012] [Indexed: 11/18/2022]
Abstract
Cyprinus carpio decoction (CCD) is a well-known Chinese food medicine formula, accepted widely as a useful therapy in preventing edema and proteinuria caused by renal disease. However, the mechanism underlying this effect remains unclear. The current study investigated the potential mechanism of CCD in alleviating nephropathy induced by adriamycin (ADR) in rats. 70 eight-week-old Wistar rats were randomly divided into normal, model, fosinopril, YD, YG groups. All rats except for the normal group received 6.5 mg/kg·bw of ADR injection into the vena caudalis once. Different doses of CCD (11.3 and 22.5 g kg(-1)) were lavaged to rats in YD and YG groups, respectively. Then the serum biochemical values of the total protein (TP), albumin (ALB), blood urea nitrogen (BUN), creatinine (Cr), electrolyte levels, and the urinary protein (UP) content in 12 hr urine were measured. Interleukin-4 (IL-4) and interferon (INF-γ) were measured by enzyme-like immunosorbent assay (ELISA). The pathomorphological analysis was observed using light and electron microscopy, and the expressions of nephrin and CD2-associated protein (CD2AP) in renal tissues were determined by immunohistochemical assay. The results indicated that CCD can relieve ADR-induced nephropathy (ADN) by improving the nutrition status, regulating the immunity, and inhibiting proteinuria by increasing nephrin and CD2AP expressions.
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Ka SM, Yeh YC, Huang XR, Chao TK, Hung YJ, Yu CP, Lin TJ, Wu CC, Lan HY, Chen A. Kidney-targeting Smad7 gene transfer inhibits renal TGF-β/MAD homologue (SMAD) and nuclear factor κB (NF-κB) signalling pathways, and improves diabetic nephropathy in mice. Diabetologia 2012; 55:509-19. [PMID: 22086159 DOI: 10.1007/s00125-011-2364-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/30/2011] [Indexed: 01/17/2023]
Abstract
AIMS/HYPOTHESIS The TGF-β/MAD homologue (SMAD) and nuclear factor κB (NF-κB) signalling pathways have been shown to play a critical role in the development of renal fibrosis and inflammation in diabetic nephropathy. We therefore examined whether targeting these pathways by a kidney-targeting Smad7 gene transfer has therapeutic effects on renal lesions in the db/db mouse model of type 2 diabetes. METHODS We delivered Smad7 plasmids into the kidney of db/db mice using kidney-targeting, ultrasound-mediated, microbubble-inducible gene transfer. The histopathology, ultrastructural pathology and pathways of TGF-β/SMAD2/3-mediated fibrosis and NF-κB-dependent inflammation were evaluated. RESULTS In this mouse model of type 2 diabetes, Smad7 gene therapy significantly inhibited diabetic kidney injury, compared with mice treated with empty vectors. Symptoms inhibited included: (1) proteinuria and renal function impairment; (2) renal fibrosis such as glomerular sclerosis, tubulo-interstitial collagen matrix abundance and renal inflammation, including Inos (also known as Nos2), Il1b and Mcp1 (also known as Ccl2) upregulation, as well as macrophage infiltration; and (3) podocyte and endothelial cell injury as demonstrated by immunohistochemistry and/or electron microscopy. Further study demonstrated that the improvement of type 2 diabetic kidney injury by overexpression of Smad7 was associated with significantly inhibited local activation of the TGF-β/SMAD and NF-κB signalling pathways in the kidney. CONCLUSIONS/INTERPRETATION Our results clearly demonstrate that kidney-targeting Smad7 gene transfer may be an effective therapy for type 2 diabetic nephropathy, acting via simultaneous modulation of the TGF-β/SMAD and NF-κB signalling pathways.
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Affiliation(s)
- S M Ka
- Graduate Institute of Aerospace and Undersea Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, Republic of China
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Abstract
Podocytes are highly differentiated cells that play an important role in maintaining glomerular filtration barrier integrity; a function regulated by small GTPase proteins of the Rho family. To investigate the role of Rho A in podocyte biology, we created transgenic mice expressing doxycycline-inducible constitutively active (V14 Rho) or dominant-negative Rho A (N19 Rho) in podocytes. Specific induction of either Rho A construct in podocytes caused albuminuria and foot process effacement along with disruption of the actin cytoskeleton as evidenced by decreased expression of the actin-associated protein synaptopodin. The mechanisms of these adverse effects, however, appeared to be different. Active V14 Rho enhanced actin polymerization, caused a reduction in nephrin mRNA and protein levels, promoted podocyte apoptosis, and decreased endogenous Rho A levels. In contrast, the dominant-negative N19 Rho caused a loss of podocyte stress fibers, did not alter the expression of either nephrin or Rho A, and did not cause podocyte apoptosis. Thus, our findings suggest that Rho A plays an important role in maintaining the integrity of the glomerular filtration barrier under basal conditions, but enhancement of Rho A activity above basal levels promotes podocyte injury.
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Ramadan R, Faour D, Awad H, Khateeb E, Cohen R, Yahia A, Torgovicky R, Cohen R, Lazari D, Kawachi H, Abassi Z. Early treatment with everolimus exerts nephroprotective effect in rats with adriamycin-induced nephrotic syndrome. Nephrol Dial Transplant 2011; 27:2231-41. [PMID: 22036940 DOI: 10.1093/ndt/gfr581] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Nephrotic syndrome (NS) is a clinical state characterized by massive proteinuria and excessive fluid retention. The effects of early versus late treatment with low or high doses of oral everolimus, a mammalian target of rapamycin inhibitor, on proteinuria in NS have not been previously described. METHODS The effects of early treatment (2 days prior to NS induction) versus late treatment (beginning 2 weeks following the establishment of NS) with a low (20 mg/L) or high (100 mg/L) dose of everolimus for 5-7 weeks on proteinuria and nephrin/podocin abundance were assessed in male adult SD rats with adriamycin-induced NS. RESULTS Adriamycin caused a significant increase in daily and cumulative proteinuria throughout the experimental period. Early, and to a lesser extent late treatment, with a low dose of everolimus, significantly decreased both daily and cumulative proteinuria and improved renal function. The anti-proteinuric effects of low-dose everolimus were associated with restoration of the disruptive glomerular nephrin/podocin abundance. In contrast, administration of a high dose of everolimus resulted in a decrease in proteinuria in NS rats, subsequently to deterioration of renal function. CONCLUSIONS Early, and to a lesser extent late treatment, with a low but not a high dose of everolimus is effective in reducing proteinuria in nephrotic rats. The mechanism may be via nephrin/podocin protection.
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Affiliation(s)
- Rawi Ramadan
- Department of Nephrology, Rambam Medical Center, Haifa, Israel
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Relevance of VEGF and nephrin expression in glomerular diseases. JOURNAL OF SIGNAL TRANSDUCTION 2011; 2011:718609. [PMID: 21808734 PMCID: PMC3144718 DOI: 10.1155/2011/718609] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 05/25/2011] [Indexed: 12/23/2022]
Abstract
The glomerular filtration barrier is affected in a large number of acquired and inherited diseases resulting in extensive leakage of plasma albumin and larger proteins, leading to nephrotic syndrome and end-stage renal disease. Unfortunately, the molecular mechanisms governing the development of the nephrotic syndrome remain poorly understood. Here, I give an overview of recent investigations that have focused on characterizing the interrelationships between the slit diaphragm components and podocytes-secreted VEGF, which have a significant role for maintaining the normal podocyte structure and the integrity of the filtering barrier.
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Perysinaki GS, Moysiadis DK, Bertsias G, Giannopoulou I, Kyriacou K, Nakopoulou L, Boumpas DT, Daphnis E. Podocyte main slit diaphragm proteins, nephrin and podocin, are affected at early stages of lupus nephritis and correlate with disease histology. Lupus 2011; 20:781-91. [PMID: 21478284 DOI: 10.1177/0961203310397412] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Renal podocytes and their slit diaphragms ensure the integrity of the renal basement membrane that forms the barrier to urinary protein loss. A putative disruption of the slit diaphragm and its main protein components, nephrin and podocin, may be implicated in the pathogenesis of lupus nephritis (LN). We studied the glomerular protein expression of nephrin and podocin in NZB/W LN mice by Western blot and immunofluorescence; mRNA levels were measured by real-time PCR. Human kidney biopsies of class II (n = 5), IV (n = 4), V (n = 7) LN were evaluated for nephrin expression by immunohistochemistry. Glomerular protein expression of nephrin and podocin were significantly reduced in NZB/W LN, starting from the earlier stages (mild mesangial LN) and becoming pronounced at advanced histological forms (focal and diffuse proliferative LN). Nephrin and podocin mRNA levels were substantially decreased in diffuse proliferative disease. Decreased expression of both proteins correlated with electron microscopy findings of distorted slit diaphragms. In patients with LN, nephrin was decreased particularly in diffuse proliferative LN. The main slit diaphragm proteins, nephrin and podocin, are affected from the earlier stages of LN and their expression correlates with disease histology. Our findings suggest a novel role of podocytes and their structures in immune-mediated nephritis.
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Affiliation(s)
- G S Perysinaki
- Laboratory of Nephrology, Medical Department, University of Crete, Greece
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Liu H, Tian N, Arany I, Bigler SA, Waxman DJ, Shah SV, Baliga R. Cytochrome P450 2B1 mediates complement-dependent sublytic injury in a model of membranous nephropathy. J Biol Chem 2010; 285:40901-10. [PMID: 20947506 PMCID: PMC3003390 DOI: 10.1074/jbc.m110.165498] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 09/27/2010] [Indexed: 11/06/2022] Open
Abstract
Membranous nephropathy is a disease that affects the filtering units of the kidney, the glomeruli, and results in proteinuria accompanied by loss of kidney function. Passive Heymann nephritis is an experimental model that mimics membranous nephropathy in humans, wherein the glomerular epithelial cell (GEC) injury induced by complement C5b-9 leads to proteinuria. We examined the role of cytochrome P450 2B1 (CYP2B1) in this complement-mediated sublytic injury. Overexpression of CYP2B1 in GECs significantly increased the formation of reactive oxygen species, cytotoxicity, and collapse of the actin cytoskeleton following treatment with anti-tubular brush-border antiserum (anti-Fx1A). In contrast, silencing of CYP2B1 markedly attenuated anti-Fx1A-induced reactive oxygen species generation and cytotoxicity with preservation of the actin cytoskeleton. Gelsolin, which maintains an organized actin cytoskeleton, was significantly decreased by complement C5b-9-mediated injury but was preserved in CYP2B1-silenced cells. In rats injected with anti-Fx1A, the cytochrome P450 inhibitor cimetidine blocked an increase in catalytic iron and ROS generation, reduced the formation of malondialdehyde adducts, maintained a normal distribution of nephrin in the glomeruli, and provided significant protection at the onset of proteinuria. Thus, GEC CYP2B1 contributes to complement C5b-9-mediated injury and plays an important role in the pathogenesis of passive Heymann nephritis.
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Affiliation(s)
- Hua Liu
- From the Departments of Pediatrics and
| | - Niu Tian
- From the Departments of Pediatrics and
| | | | - Steven A. Bigler
- Pathology, University of Mississippi Medical Center, Jackson, Mississippi 39216
| | - David J. Waxman
- the Division of Cell and Molecular Biology, Department of Biology, Boston University, Boston, Massachusetts 02215, and
| | - Sudhir V. Shah
- the Division of Nephrology, Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
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Triptolide reduces proteinuria in experimental membranous nephropathy and protects against C5b-9-induced podocyte injury in vitro. Kidney Int 2010; 77:974-88. [DOI: 10.1038/ki.2010.41] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ohse T, Vaughan MR, Kopp JB, Krofft RD, Marshall CB, Chang AM, Hudkins KL, Alpers CE, Pippin JW, Shankland SJ. De novo expression of podocyte proteins in parietal epithelial cells during experimental glomerular disease. Am J Physiol Renal Physiol 2009; 298:F702-11. [PMID: 20007346 DOI: 10.1152/ajprenal.00428.2009] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Studies have shown that certain cells of the glomerular tuft begin to express proteins considered unique to other cell types upon injury. Little is known about the response of parietal epithelial cells (PEC) to injury. To determine whether PECs change their phenotype upon injury to also express proteins traditionally considered podocyte specific, the following four models of glomerular disease were studied: the transforming growth factor (TGF)-beta1 transgenic mouse model of global glomerulosclerosis, the adriamycin model of focal segmental glomerulosclerosis (FSGS), the anti-glomerular basement membrane (GBM) model of crescentic glomerulonephritis, and the passive Heymann nephritis model of membranous nephropathy. Double immunostaining was performed with antibodies to podocyte-specific proteins (synaptopodin and Wilms' tumor 1) and antibodies to PEC specific proteins (paired box gene 8 and claudin-1). No double staining was detected in normal mice. In contrast, the results showed a statistical increase in the number of cells attached to Bowman basement membrane that were double-positive for both podocyte/PEC proteins in TGF-beta1 transgenic, anti-GBM, and membranous animals. Double-positive cells for both podocyte and PEC proteins were also statistically increased in the glomerular tuft in TGF-beta1 transgenic, anti-GBM, and FSGS mice. These results are consistent with glomerular cells coexpressing podocyte and PEC proteins in experimental glomerular disease, but not under normal circumstances.
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Affiliation(s)
- Takamoto Ohse
- Division of Nephrology, University of Washington, Seattle, Washington 98195-6521, USA
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Fukasawa H, Bornheimer S, Kudlicka K, Farquhar MG. Slit diaphragms contain tight junction proteins. J Am Soc Nephrol 2009; 20:1491-503. [PMID: 19478094 DOI: 10.1681/asn.2008101117] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Slit diaphragms are essential components of the glomerular filtration apparatus, as changes in these junctions are the hallmark of proteinuric diseases. Slit diaphragms, considered specialized adherens junctions, contain both unique membrane proteins (e.g., nephrin, podocin, and Neph1) and typical adherens junction proteins (e.g., P-cadherin, FAT, and catenins). Whether slit diaphragms also contain tight junction proteins is unknown. Here, immunofluorescence, immunogold labeling, and cell fractionation demonstrated that rat slit diaphragms contain the tight junction proteins JAM-A (junctional adhesion molecule A), occludin, and cingulin. We found these proteins in the same protein complexes as nephrin, podocin, CD2AP, ZO-1, and Neph1 by cosedimentation, coimmunoprecipitation, and pull-down assays. PAN nephrosis increased the protein levels of JAM-A, occludin, cingulin, and ZO-1 several-fold in glomeruli and loosened their attachment to the actin cytoskeleton. These data extend current information about the molecular composition of slit diaphragms by demonstrating the presence of tight junction proteins, although slit diaphragms lack the characteristic morphologic features of tight junctions. The contribution of these proteins to the assembly of slit diaphragms and potential signaling cascades requires further investigation.
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Affiliation(s)
- Hirotaka Fukasawa
- Department of Cellular and Molecular Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0651, USA
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Slit diaphragm dysfunction in proteinuric states: identification of novel therapeutic targets for nephrotic syndrome. Clin Exp Nephrol 2009; 13:275-280. [PMID: 19266252 DOI: 10.1007/s10157-009-0162-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Accepted: 02/05/2009] [Indexed: 12/20/2022]
Abstract
Several recent studies have demonstrated that the slit diaphragm of the glomerular epithelial cell (podocyte) is the structure likely to be the principal barrier in the glomerular capillary wall. Nephrin identified as a gene product mutated in congenital nephrotic syndrome located at the outer leaflet of plasma membranes of the slit diaphragm. The anti-nephrin antibody is capable of inducing massive proteinuria, which indicates that nephrin is a key functional molecule in the slit diaphragm. Expression of nephrin was reduced in glomeruli of minimal change nephrotic syndrome. Some recent studies demonstrated that podocin, CD2-associated protein and NEPH1 are also functional molecules in the slit diaphragm, and their expressions are altered in membranous nephropathy and also in focal glomerulosclerosis. These observations suggested that the alteration of the molecular arrangement in the slit diaphragm is involved in the development of proteinuria in several kinds of glomerular diseases. Recent studies of our group have demonstrated that type 1 receptor-mediated angiotensin II action reduced the expression of the slit diaphragm-associated molecules and that type 1 receptor blockade ameliorated proteinuria by preventing the function of angiotensin II on the slit diaphragm. By the subtraction hybridization techniques using glomerular cDNA of normal and proteinuric rats, we detected that synaptic vesicle protein 2B and ephrin B1 are involved in the maintenance of the barrier function of the slit diaphragm.
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Fujimura T, Yamagishi SI, Ueda S, Fukami K, Shibata R, Matsumoto Y, Kaida Y, Hayashida A, Koike K, Matsui T, Nakamura KI, Okuda S. Administration of pigment epithelium-derived factor (PEDF) reduces proteinuria by suppressing decreased nephrin and increased VEGF expression in the glomeruli of adriamycin-injected rats. Nephrol Dial Transplant 2008; 24:1397-406. [DOI: 10.1093/ndt/gfn659] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Tesař V, Zima T. Recent Progress in the Pathogenesis of Nephrotic Proteinuria. Crit Rev Clin Lab Sci 2008; 45:139-220. [DOI: 10.1080/10408360801934865] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Wang L, Ellis MJ, Fields TA, Howell DN, Spurney RF. Beneficial effects of the Rho kinase inhibitor Y27632 in murine puromycin aminonucleoside nephrosis. Kidney Blood Press Res 2008; 31:111-21. [PMID: 18367845 PMCID: PMC2821439 DOI: 10.1159/000121531] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 01/08/2008] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND AIMS Rho kinase (ROCK) inhibition reduces systemic blood pressure (BP) and decreases renal damage in animal models of kidney disease. The aim of this study was to determine if ROCK inhibition might have beneficial effects in glomerular disease processes that are independent of systemic BP. METHODS We investigated the effects of the ROCK inhibitor Y27632 and hydralazine in murine puromycin aminonucleoside (PAN) nephrosis. RESULTS Treatment with either Y27632 or hydralazine similarly reduced systolic BP compared to vehicle-treated controls. Seven days after treatment with PAN, albuminuria, proteinuria and effacement of podocyte foot processes were significantly reduced in Y27632- and hydralazine-treated mice compared to vehicle-treated animals. Treatment with PAN significantly reduced expression of the podocyte proteins nephrin and Neph1, and the loss of glomerular nephrin was attenuated by treatment with Y27632 but not by treatment with hydralazine. In cultured podocytes, PAN potently activated both Rho and ROCK, and PAN-induced ROCK activation was prevented by Y27632. CONCLUSIONS The ROCK inhibitor Y27632 attenuated glomerular nephrin loss in murine PAN nephrosis independent of its effects on systemic BP.
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Affiliation(s)
- Liming Wang
- Division of Nephrology, Department of Medicine, and Durham VA Medical Centers, Durham, N.C., USA
| | - Mathew J. Ellis
- Division of Nephrology, Department of Medicine, and Durham VA Medical Centers, Durham, N.C., USA
| | - Timothy A. Fields
- Department of Pathology, Duke University and Durham VA Medical Centers, Durham, N.C., USA
| | - David N. Howell
- Department of Pathology, Duke University and Durham VA Medical Centers, Durham, N.C., USA
| | - Robert F. Spurney
- Division of Nephrology, Department of Medicine, and Durham VA Medical Centers, Durham, N.C., USA
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Nakhoul F, Khankin E, Yaccob A, Kawachi H, Karram T, Awaad H, Nakhoul N, Hoffman A, Abassi Z. Eplerenone potentiates the antiproteinuric effects of enalapril in experimental nephrotic syndrome. Am J Physiol Renal Physiol 2008; 294:F628-37. [DOI: 10.1152/ajprenal.00524.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nephrotic syndrome (NS) is a clinical state characterized by massive proteinuria and edema. It is believed that nephrin and podocin are involved in the development of proteinuria. The proteinuria and effects of eplerenone alone or combined with enalapril on nephrin/podocin abundance in rats with NS have not yet been studied. Therefore, the present study was designed to examine the early (beginning 2 days before NS induction) and late (beginning 2 wk after NS induction) effects of eplerenone and enalapril, alone or combined, on proteinuria and nephrin/podocin abundance in rats with adriamycin-induced NS. Adriamycin caused a significant increase in daily protein excretion (UprV; from 26.96 ± 3.43 to 958.57 ± 56.7 mg/day, P < 0.001) and cumulative proteinuria [from 900.33 ± 135.5 to 22,490.62 ± 931.26 mg ( P < 0.001)] during 6 wk. Early treatment with enalapril significantly decreased UprV from 958.6 ± 56.7 to 600.31 ± 65.13 mg/day ( P < 0.001) and cumulative proteinuria to 12,842.37 ± 1,798.17 mg/6 wk ( P < 0.001). Similarly, early treatment with eplerenone produced a profound antiproteinuric effect: UprV decreased from 958.57 ± 56.7 to 593.38 ± 21.83 mg/day, P < 0.001, and cumulative proteinuria to 16,601.84 ± 1,334.31 mg/6 wk; P < 0.001. An additive effect was obtained when enalapril and eplerenone were combined: UprV decreased from 958.57 ± 56.69 to 424.17 ± 38.54 mg/day, P < 0.001, and cumulative protein excretion declined to 10,252.88 ± 1,011.3 mg/6 wk, P < 0.001. These antiproteinuric effects were associated with substantial preservation of glomerular nephrin and podocin. In contrast, late treatment with either enalapril or eplerenone alone or combined mildly decreased UprV and cumulative proteinuria. Thus pretreatment with eplerenone or enalapril is effective in reducing daily and cumulative protein excretion and preservation of nephrin/podocin. More profound antiproteinuric effects were obtained when enalapril and eplerenone were combined.
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Kocherlakota KS, Wu JM, McDermott J, Abmayr SM. Analysis of the cell adhesion molecule sticks-and-stones reveals multiple redundant functional domains, protein-interaction motifs and phosphorylated tyrosines that direct myoblast fusion in Drosophila melanogaster. Genetics 2008; 178:1371-83. [PMID: 18245830 PMCID: PMC2278097 DOI: 10.1534/genetics.107.083808] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 12/14/2007] [Indexed: 01/16/2023] Open
Abstract
The larval body wall muscles of Drosophila melanogaster arise by fusion of founder myoblasts (FMs) and fusion-competent myoblasts (FCMs). Sticks-and-Stones (SNS) is expressed on the surface of all FCMs and mediates adhesion with FMs and developing syncytia. Intracellular components essential for myoblast fusion are then recruited to these adhesive contacts. In the studies herein, a functional analysis of the SNS cytodomain using the GAL4/UAS system identified sequences that direct myoblast fusion, presumably through recruitment of these intracellular components. An extensive series of deletion and site-directed mutations were evaluated for their ability to rescue the myoblast fusion defects of sns mutant embryos. Deletion studies revealed redundant functional domains within SNS. Surprisingly, highly conserved consensus sites for binding post-synaptic density-95/discs large/zonula occludens-1-domain-containing (PDZ) proteins and serines with a high probability of phosphorylation play no significant role in myoblast fusion. Biochemical studies establish that the SNS cytodomain is phosphorylated at multiple tyrosines and their site-directed mutagenesis compromises the ability of the corresponding transgenes to rescue myoblast fusion. Similar mutagenesis revealed a requirement for conserved proline-rich regions. This complexity and redundancy of multiple critical sequences within the SNS cytodomain suggest that it functions through a complex array of interactions that likely includes both phosphotyrosine-binding and SH3-domain-containing proteins.
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Collino F, Bussolati B, Gerbaudo E, Marozio L, Pelissetto S, Benedetto C, Camussi G. Preeclamptic sera induce nephrin shedding from podocytes through endothelin-1 release by endothelial glomerular cells. Am J Physiol Renal Physiol 2008; 294:F1185-94. [PMID: 18287402 DOI: 10.1152/ajprenal.00442.2007] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In preeclampsia (PE), proteinuria has been associated with a reduced expression of nephrin by podocytes. In the present study, we investigated in vitro on human cultured podocytes the mechanism responsible for nephrin loss in PE. Sera from patients with PE did not directly downregulate the expression of nephrin. In contrast, conditioned medium obtained from glomerular endothelial cells incubated with PE sera induced loss of nephrin and synaptopodin, but not of podocin, from podocytes. Nephrin loss was related to a rapid shedding of the protein from the cell surface due to cleavage of its extracellular domain by proteases and to cytoskeleton redistribution. The absence of nephrin mRNA downregulation together with nephrin reexpression within 24 h confirm that the loss of nephrin was not related to a reduced synthesis. Studies with an endothelin-1 (ET-1) receptor antagonist that abrogated the loss of nephrin triggered by glomerular endothelial conditioned medium of PE sera indicated that ET-1 was the main effector of nephrin loss. Indeed, ET-1 was synthesized and released from glomerular endothelial cells when incubated with PE sera, and recombinant ET-1 triggered nephrin shedding from podocytes. Moreover, VEGF blockade induced ET-1 release from endothelial cells, and in turn the conditioned medium obtained triggered nephrin loss. In conclusion, the present study identifies a potential mechanism of nephrin loss in PE that may link endothelial injury with enhanced glomerular permeability.
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Affiliation(s)
- Federica Collino
- Department of Internal Medicine, Research Centre for Experimental Medicine and Molecular Biotechnology Center, University of Torino, Torino, Italy
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van Deutekom JC, Janson AA, Ginjaar IB, Frankhuizen WS, Aartsma-Rus A, Bremmer-Bout M, den Dunnen JT, Koop K, van der Kooi AJ, Goemans NM, de Kimpe SJ, Ekhart PF, Venneker EH, Platenburg GJ, Verschuuren JJ, van Ommen GJB. Local dystrophin restoration with antisense oligonucleotide PRO051. N Engl J Med 2007; 357:2677-86. [PMID: 18160687 DOI: 10.1056/nejmoa073108] [Citation(s) in RCA: 652] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Duchenne's muscular dystrophy is associated with severe, progressive muscle weakness and typically leads to death between the ages of 20 and 35 years. By inducing specific exon skipping during messenger RNA (mRNA) splicing, antisense compounds were recently shown to correct the open reading frame of the DMD gene and thus to restore dystrophin expression in vitro and in animal models in vivo. We explored the safety, adverse-event profile, and local dystrophin-restoring effect of a single, intramuscular dose of an antisense oligonucleotide, PRO051, in patients with this disease. METHODS Four patients, who were selected on the basis of their mutational status, muscle condition, and positive exon-skipping response to PRO051 in vitro, received a dose of 0.8 mg of PRO051 injected into the tibialis anterior muscle. A biopsy was performed 28 days later. Safety measures, composition of mRNA, and dystrophin expression were assessed. RESULTS PRO051 injection was not associated with clinically apparent adverse events. Each patient showed specific skipping of exon 51 and sarcolemmal dystrophin in 64 to 97% of myofibers. The amount of dystrophin in total protein extracts ranged from 3 to 12% of that found in the control specimen and from 17 to 35% of that of the control specimen in the quantitative ratio of dystrophin to laminin alpha2. CONCLUSIONS Intramuscular injection of antisense oligonucleotide PRO051 induced dystrophin synthesis in four patients with Duchenne's muscular dystrophy who had suitable mutations, suggesting that further studies might be feasible.
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Affiliation(s)
- Judith C van Deutekom
- Department of Human and Clinical Genetics, Leiden University Medical Center, The Netherlands.
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Ronco P, Debiec H. Target antigens and nephritogenic antibodies in membranous nephropathy: of rats and men. Semin Immunopathol 2007; 29:445-58. [PMID: 17899086 DOI: 10.1007/s00281-007-0091-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 08/17/2007] [Indexed: 01/31/2023]
Abstract
Membranous nephropathy, a disease characterized by an accumulation of immune deposits on the outer aspect of the glomerular basement membrane, is the most common cause of idiopathic nephrotic syndrome in white adults. In the rat model of Heymann nephritis, the target antigen of antibodies is megalin, a multiligand receptor expressed at the podocyte cell surface. This review summarizes key findings provided by this experimental model and by our discovery of neutral endopeptidase being the alloantigen involved in neonatal cases of membranous nephropathy. We discuss the role of alloimmunization as a new mechanism of renal disease and the approach that we use to identify new podocyte antigens. We also summarize current knowledge on the mechanism of proteinuria, with special emphasis on the role of complement. In conclusion, substantial progresses have been made in understanding molecular mechanisms of membranous nephropathy, which should lead to novel therapeutic approaches.
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Affiliation(s)
- P Ronco
- INSERM Unit 702, Hôpital Tenon, 4 rue de la Chine, 75020, Paris, France.
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Suzuki K, Han GD, Miyauchi N, Hashimoto T, Nakatsue T, Fujioka Y, Koike H, Shimizu F, Kawachi H. Angiotensin II type 1 and type 2 receptors play opposite roles in regulating the barrier function of kidney glomerular capillary wall. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:1841-53. [PMID: 17525253 PMCID: PMC1899458 DOI: 10.2353/ajpath.2007.060484] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Although angiotensin II (Ang II) type 1 receptor antagonist ameliorates proteinuria, its pharmacological mechanism and the differential roles of Ang II type 1 receptor (AT1R) and type 2 receptor (AT2R) are not well understood. We analyzed the effect of Ang II type 1 receptor antagonist on proteinuria caused by antibody against nephrin, a functional molecule of glomerular slit diaphragm and dysfunction of which is involved in the development of proteinuria in several glomerular diseases. We show here that AT1R antagonist ameliorated proteinuria by preventing a reduction in the functional molecules of the slit diaphragm. We also analyzed the role of AT1R- or AT2R-mediated actions on the expression of the slit diaphragm molecules in an in vivo study of normal rat and in an in vitro study of cultured podocytes. AT1R-mediated action hampered the mRNA expression of the slit diaphragm molecules, whereas AT2R-mediated action enhanced it. These findings indicate that Ang II receptor subtypes play opposite roles in regulating the barrier function of glomerular capillary wall and that the enhancement of AT2R stimulation may serve as a potential therapeutic strategy for proteinuria.
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MESH Headings
- Angiotensin II/metabolism
- Angiotensin II Type 1 Receptor Blockers/metabolism
- Angiotensin II Type 2 Receptor Blockers
- Animals
- Antibodies, Monoclonal/metabolism
- Antibodies, Monoclonal/toxicity
- Capillaries/cytology
- Capillaries/metabolism
- Female
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Kidney Glomerulus/cytology
- Kidney Glomerulus/metabolism
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Phosphoproteins/genetics
- Phosphoproteins/metabolism
- Podocytes/cytology
- Podocytes/metabolism
- Proteinuria
- Rats
- Receptor, Angiotensin, Type 1/agonists
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Receptor, Angiotensin, Type 2/agonists
- Receptor, Angiotensin, Type 2/genetics
- Receptor, Angiotensin, Type 2/metabolism
- Sialoglycoproteins/genetics
- Sialoglycoproteins/metabolism
- Zonula Occludens-1 Protein
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Affiliation(s)
- Koichi Suzuki
- Department of Cell Biology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Niigata, 951-8510, Japan
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45
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Gaidos G, Soni S, Oswald DJ, Toselli PA, Kirsch KH. Structure and function analysis of the CMS/CIN85 protein family identifies actin-bundling properties and heterotypic-complex formation. J Cell Sci 2007; 120:2366-77. [PMID: 17606992 DOI: 10.1242/jcs.004333] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Members of the CMS/CIN85 protein family participate in clathrin-mediated endocytosis and play a crucial role in maintaining the kidney filtration barrier. The CMS protein structure includes three Src homology 3 (SH3) domains and a proline-rich (PR) region that is connected by a `linker' sequence to a coiled-coil (CC) domain. We show that CMS is a component of special actin-rich adhesion structures – podosomes – and demonstrate specific actin-binding properties of CMS. We have found that the entire C-terminal half of CMS is necessary for efficient binding to filamentous actin (F-actin). CMS and CIN85 can crosslink F-actin into bundles, a function that depends on the PR region and the CC domain. Removal of these domains reduces migration. CMS can also form heterotypic complexes with CIN85. CIN85 is expressed as multiple isoforms that share the CC domain, suggesting that heterotypic interactions with CMS provides a mechanism to regulate CMS binding to F-actin and thus for modulating dynamic rearrangements of the cytoskeleton.
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Affiliation(s)
- Gabriel Gaidos
- Department of Biochemistry, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118, USA
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Thibaudin D, Thibaudin L, Berthoux P, Mariat C, Filippis JP, Laurent B, Alamartine E, Berthoux F. TNFA2 and d2 alleles of the tumor necrosis factor alpha gene polymorphism are associated with onset/occurrence of idiopathic membranous nephropathy. Kidney Int 2007; 71:431-7. [PMID: 17213876 DOI: 10.1038/sj.ki.5002054] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Idiopathic membranous nephropathy (IMN) has a strong association with the major histocompatibility complex HLA B8DR3(17)DQ2 haplotype. The tumor necrosis factor (TNF)A gene is located within the major histocompatibility complex region on chromosome 6. We have studied the influence of two functional polymorphisms; the -308 (promoter region) and the TNFd microsatellites on initiation and/or progression of IMN. This was a case-control study comparing data from 100 Caucasians patients (67 male subjects; 67%) with IMN to 232 Caucasians local controls (171 male subjects; 74%). We have analyzed genotypes and alleles distributions and the role of these polymorphisms in disease progression towards end-stage renal failure or patient death. For -308 TNFA polymorphism, distribution of genotypes was significantly different between IMN and controls (chi(2)=16.25; P=0.0003): the A2 allele frequency was 28.0% in IMN vs 15.3% in controls (chi(2)=14.57; P=0.0001). For TNFd polymorphism, alleles distribution (from d1 to d7) was also significantly different between IMN and controls (chi(2)=56.74; P<0.0001) with both diminished d3 allele frequency (chi(2)=27.30; P<0.0001; Pc=0.001) and increased d2 allele frequency (chi(2)=29.95; P<0.0001; Pc=0.001) in IMN. We could not isolate any significant and independent influence of these different genotypes on IMN disease progression. The TNFA2 and TNFd2 alleles were strongly associated with occurrence/initiation of IMN and should be considered as susceptibility genes for this disease.
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Affiliation(s)
- D Thibaudin
- Nephrology, Dialysis and Renal Transplantation Department, North University Hospital, Saint-Etienne, France
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Abstract
PURPOSE OF REVIEW Membranous nephropathy is one of the most common glomerulopathies. Current treatments are entirely empirical, and concept-driven therapies are dramatically lacking. This review focuses on new pathophysiologic aspects of the disease, with special emphasis on the antigenic targets of pathogenic antibodies. RECENT FINDINGS Neutral endopeptidase - a podocyte antigen that can digest biologically active peptides - was recently identified as the target antigen of antibodies deposited in the subepithelial space of glomeruli in a subset of patients with antenatal membranous nephropathy. The mothers became immunized because they are deficient in neutral endopeptidase due to truncating mutations in the gene. Membranous nephropathy could be transferred to the rabbit by injection of mothers' immunoglobulin. Development of the renal disease was associated with anti-neutral endopeptidase IgG1. SUMMARY Membranous nephropathy most likely is a heterogeneous disease, although a common denominator may be that podocytes provide antigenic targets for in-situ formation of glomerular immune deposits. Identification of neutral endopeptidase and additional (podocyte) antigens and characterization of their epitopes should make it possible to design more effective and better tolerated therapies. Fetomaternal alloimmunization is a novel mechanism of renal disease that may apply to other organs as well.
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Sung SH, Ziyadeh FN, Wang A, Pyagay PE, Kanwar YS, Chen S. Blockade of vascular endothelial growth factor signaling ameliorates diabetic albuminuria in mice. J Am Soc Nephrol 2006; 17:3093-104. [PMID: 16988063 DOI: 10.1681/asn.2006010064] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
For investigation of how the vascular endothelial growth factor (VEGF) system participates in the pathogenesis of diabetic kidney disease, type 2 diabetic db/db and control db/m mice were treated intraperitoneally with vehicle or 2 mg/kg of a pan-VEGF receptor tyrosine kinase inhibitor, SU5416, twice a week for 8 wk. Efficacy of SU5416 treatment in the kidney was verified by the inhibition of VEGF receptor-1 phosphorylation. Glomerular VEGF immunostaining, normally increased in diabetes, was unaffected by SU5416. Plasma creatinine did not change with diabetes or SU5416 treatment. The primary end point of albuminuria increased approximately four-fold in the diabetic db/db mice but was significantly ameliorated by SU5416. Correlates of albuminuria were investigated. Diabetic glomerular basement membrane thickening was prevented in the SU5416-treated db/db mice, whereas mesangial matrix expansion remained unchanged by treatment. The density of open slit pores between podocyte foot processes was decreased in db/db diabetes but was partly increased toward normal by SU5416. Finally, nephrin protein by immunofluorescence was decreased in the db/db mice but was significantly restored by SU5416. Paradoxically, total nephrin protein by immunoblotting was increased in diabetes, pointing toward a possible dysregulation of nephrin trafficking. Diabetic albuminuria is partially a function of VEGF receptor signaling overactivity. VEGF signaling was found to affect a number of podocyte-driven manifestations such as GBM thickening, slit pore density, and nephrin quantity, all of which are associated with the extent of diabetic albuminuria. By impeding these pathophysiologic processes, VEGF receptor inhibition by SU5416 might become a useful adjunct to anti-albuminuria therapy in diabetic nephropathy.
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Affiliation(s)
- Sun Hee Sung
- Renal-Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Miyauchi N, Saito A, Karasawa T, Harita Y, Suzuki K, Koike H, Han GD, Shimizu F, Kawachi H. Synaptic vesicle protein 2B is expressed in podocyte, and its expression is altered in proteinuric glomeruli. J Am Soc Nephrol 2006; 17:2748-59. [PMID: 16943307 DOI: 10.1681/asn.2005121293] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Synaptic vesicle protein 2B (SV2B) was identified by the subtraction hybridization technique as a molecule of which mRNA expression was decreased in puromycin aminonucleoside (PAN) nephropathy by glomerular cDNA subtraction assay. The expression of SV2B was detected in glomerular lysate with Western blot analysis. Dual-labeling immunofluorescence studies with glomerular cell markers demonstrated that SV2B is expressed in glomerular visceral epithelial cells (podocytes). The expression of SV2B is detected also in cultured podocyte and in human kidney section as podocytic pattern. The decrease of SV2B mRNA was already detected before the onset of proteinuria in PAN nephropathy. The mRNA expression of SV2B clearly is altered not only in PAN nephropathy but also in another proteinuric state that is caused by an antibody against nephrin, a functional molecule of the slit diaphragm. The decreased intensity in SV2B staining was already detected before the peak of proteinuria in both models with immunofluorescence study. A reduced amount of SV2B was detected in both models also with Western blot analysis. CD2AP, another functional molecule of the slit diaphragm, was observed in cytoplasm, including the processes area of the cultured podocyte, and when the podocyte was treated with small interfering RNA for SV2B, CD2AP staining at the process area was not detected. These results suggest that SV2B is a functional molecule of podocyte, and SV2B may play a role in the expression and proper localization of CD2AP.
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Affiliation(s)
- Naoko Miyauchi
- Department of Cell Biology, Institute of Nephrology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Niigata 951-8510, Japan
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50
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Fan Q, Xing Y, Ding J, Guan N, Zhang J. The relationship among nephrin, podocin, CD2AP, and alpha-actinin might not be a true 'interaction' in podocyte. Kidney Int 2006; 69:1207-15. [PMID: 16501493 DOI: 10.1038/sj.ki.5000245] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The abnormality of a single podocyte molecule, caused by a single gene mutation, such as NPHS1, NPHS2, CD2AP, and ACTN4, can lead to the hereditary/congenital nephrotic syndromes (NS). Further studies suggested that more than one podocyte molecule were together involved in acquired or experimental NS. However, we do not know much on the relationship among these podocyte molecules, and the molecular response induced by the change of each podocyte protein to the remaining ones. We respectively knockdown the nephrin, podocin, CD2AP, or alpha-actinin-4 mRNA by using reconstructed RNA interference vector--psiRNA-hH1GFPzeo in mouse podocyte clone. The molecular behavior or response was revealed by the quantitative expression both at mRNA and protein levels with RT-PCR and Western blot, and by the molecular distribution detected with confocal microscopy. With nephrin knockdown, only CD2AP increased, whereas podocin showed no change. Contrarily, with podocin or CD2AP knockdown, nephrin decreased, while CD2AP or podocin increased. Nephrin, podocin, or CD2AP knockdown did not change the expression of alpha-actinin-4, whereas alpha-actinin-4 knockdown begetted the reduction of nephrin, and the increment of podocin and CD2AP. The redistributions of nephrin, podocin, and CD2AP were revealed around a predominant nuclear staining compared with the membrane surface staining in the control podocytes. Our data imply that the response between the four podocyte molecules is very complicated and evidently different. There is not always an interaction between podocyte molecules. The normal localization of podocyte molecules would depend on their normal expression quantity and the molecular reactions between them.
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Affiliation(s)
- Q Fan
- Department of Pediatrics, Peking University First Hospital, Beijing, Peoples Republic of China
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