scholarly journals Glomerular Expression of Dystroglycans Is Reduced in Minimal Change Nephrosis But Not in Focal Segmental Glomerulosclerosis

2000 ◽  
Vol 11 (3) ◽  
pp. 403-412 ◽  
Author(s):  
HEINRICH M. REGELE ◽  
EDITH FILLIPOVIC ◽  
BRIGITTE LANGER ◽  
HELGA POCZEWKI ◽  
ILSE KRAXBERGER ◽  
...  
Keyword(s):  
Focal Segmental Glomerulosclerosis ◽  
Immunoelectron Microscopy ◽  
Minimal Change ◽  
Matrix Proteins ◽  
Membrane Domains ◽  
Segmental Glomerulosclerosis ◽  
Pathologic Features ◽  
Minimal Change Nephrosis ◽  
Foot Process ◽  
Quantitative Immunoelectron Microscopy

Abstract. Extensive flattening of podocyte foot processes and increased permeability of the glomerular capillary filter are the major pathologic features of minimal change nephrosis (MCN) and focal segmental glomerulosclerosis (FSGS). Adhesion proteins anchor and stabilize podocytes on the glomerular basement membrane (GBM), and presumably are involved in the pathogenesis of foot process flattening. Thus far, α3 β1-integrin was localized to basal cell membrane domains. In this report, α- and β-dystroglycan (DG) were detected at precisely the same location by immunoelectron microscopy, and the presence of α- and β-DG chains was confirmed by immunoblotting on isolated human glomeruli. Because the major DG binding partners in the GBM (laminin, agrin, perlecan), and the intracellular dystrophin analogue utrophin are also present in glomeruli, it appears that podocytes adhere to the GBM via DG complexes, similar to muscle fibers in which actin is linked via dystrophin and DG to the extracellular matrix. As with muscle cells, it is therefore plausible that podocytes use precisely actin-guided DG complexes at their “soles” to actively govern the topography of GBM matrix proteins. Expression of the α/β-DG complex was reported to be reduced in muscular dystrophies, and therefore a search for similar pathologic alterations in archival kidney biopsies from patients with MCN (n = 16) and FSGS (n = 8) was conducted by quantitative immunoelectron microscopy. The density of α-DG on the podocyte's soles was significantly reduced to 25% in MCN, whereas it was not different in normal kidneys and FSGS. The expression of β-DG was reduced to >50% in MCN, and was slightly increased in FSGS. Levels of DG expression returned to normal in MCN after steroid treatment (n = 4). Expression of β1-integrin remained at normal levels in all conditions. These findings point to different potentially pathogenic mechanisms of foot process flattening in MCN and FSGS.

scholarly journals Expression of Nephrin in Pediatric Kidney Diseases

2001 ◽  
Vol 12 (2) ◽  
pp. 289-296
Author(s):  
JAAKKO PATRAKKA ◽  
VESA RUOTSALAINEN ◽  
ILKKA KETOLA ◽  
CHRISTER HOLMBERG ◽  
MARKKU HEIKINHEIMO ◽  
...  
Keyword(s):  
Focal Segmental Glomerulosclerosis ◽  
Membranous Nephropathy ◽  
Staining Pattern ◽  
Kidney Diseases ◽  
Minimal Change ◽  
Slit Diaphragm ◽  
Segmental Glomerulosclerosis ◽  
Minimal Change Nephrosis ◽  
Pediatric Kidney Diseases

Abstract. Nephrin is a podocyte cell adhesion protein located at the slit diaphragm area of the kidney glomerulus. Mutations in the nephrin gene (NPHS1) lead to congenital nephrosis, suggesting that nephrin is essential for the glomerular filtration barrier. This prompted this study of the expression of nephrin in acquired pediatric kidney diseases usingin situhybridization and immunohistochemistry.In situhybridization for nephrin mRNA was performed in biopsy samples from patients with proteinuria caused by minimal change nephrosis, focal segmental glomerulosclerosis, and membranous nephropathy. The expression of nephrin mRNA was evaluated by grading the signal intensity visually and by counting the number of grains in separate glomeruli. No significant difference was observed in these samples as compared with controls. Immunostaining for nephrin was performed using antibodies directed against extra- and intracellular parts of the molecule. Nephrin staining gave a linear pattern along the glomerular capillary loops. In minimal change nephrosis, focal segmental glomerulosclerosis, and membranous nephropathy, the distribution of nephrin was similar to that in controls. In proliferative forms of glomerulonephritides (Henoch-Schönlein nephritis, IgA nephropathy, postinfectious and membranoproliferative glomerulonephritis), crescents and sclerotic lesions were negative for nephrin, and mesangial proliferation led to a scattered and sparse staining pattern. The staining pattern of nephrin was compared to that of ZO-1, a component of the cytoplasmic face of the slit diaphragm. The distributions of these two proteins in capillary tufts were similar in all disease entities studied. In conclusion, immunohistochemistry andin situhybridization did not reveal major alterations in the expression of nephrin in proteinuric kidney diseases in children. Further studies are needed for more precise evaluation of the role of nephrin in these diseases.

scholarly journals Clinical manifestations of focal segmental glomerulosclerosis in Japan from the Japan Renal Biopsy Registry: age stratification and comparison with minimal change disease

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takaya Ozeki ◽  
Shoichi Maruyama ◽  
Toshiyuki Imasawa ◽  
Takehiko Kawaguchi ◽  
Hiroshi Kitamura ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Renal Biopsy ◽  
Focal Segmental Glomerulosclerosis ◽  
Clinical Diagnosis ◽  
Clinical Characteristics ◽  
Minimal Change Disease ◽  
Multivariable Analysis ◽  
Laboratory Data ◽  
Minimal Change ◽  
Segmental Glomerulosclerosis

AbstractFocal segmental glomerulosclerosis (FSGS) is a serious condition leading to kidney failure. We aimed to investigate the clinical characteristics of FSGS and its differences compared with minimal change disease (MCD) using cross-sectional data from the Japan Renal Biopsy Registry. In Analysis 1, primary FSGS (n = 996) were stratified by age into three groups: pediatric (< 18 years), adult (18–64 years), and elderly (≥ 65 years), and clinical characteristics were compared. Clinical diagnosis of nephrotic syndrome (NS) was given to 73.5% (97/132) of the pediatric, 41.2% (256/622) of the adult, and 65.7% (159/242) of the elderly group. In Analysis 2, primary FSGS (n = 306) and MCD (n = 1303) whose clinical diagnosis was nephrotic syndrome (NS) and laboratory data were consistent with NS, were enrolled. Logistic regression analysis was conducted to elucidate the variables which can distinguish FSGS from MCD. On multivariable analysis, higher systolic blood pressure, higher serum albumin, lower eGFR, and presence of hematuria associated with FSGS. In Japanese nationwide registry, primary FSGS patients aged 18–64 years showed lower rate of NS than those in other ages. Among primary nephrotic cases, FSGS showed distinct clinical features from MCD.

scholarly journals Mechanical challenges and cytoskeletal impairments in focal segmental glomerulosclerosis

2018 ◽  
Vol 314 (5) ◽  
pp. F921-F925 ◽  
Author(s):  
Di Feng ◽  
Clark DuMontier ◽  
Martin R. Pollak
Keyword(s):  
Blood Flow ◽  
Focal Segmental Glomerulosclerosis ◽  
Kidney Injury ◽  
Future Research ◽  
Disease States ◽  
Filtration Barrier ◽  
Segmental Glomerulosclerosis ◽  
The Face ◽  
Foot Process ◽  
Future Research Directions

Focal segmental glomerulosclerosis (FSGS) is a histologically defined form of kidney injury typically mediated by podocyte dysfunction. Podocytes rely on their intricate actin-based cytoskeleton to maintain the glomerular filtration barrier in the face of mechanical challenges resulting from pulsatile blood flow and filtration of this blood flow. This review summarizes the mechanical challenges faced by podocytes in the form of stretch and shear stress, both of which may play a role in the progression of podocyte dysfunction and detachment. It also reviews how podocytes respond to these mechanical challenges in dynamic fashion through rearranging their cytoskeleton, triggering various biochemical pathways, and, in some disease states, altering their morphology in the form of foot process effacement. Furthermore, this review highlights the growing body of evidence identifying several mutations of important cytoskeleton proteins as causes of FSGS. Lastly, it synthesizes the above evidence to show that a better understanding of how these mutations leave podocytes vulnerable to the mechanical challenges they face is essential to better understanding the mechanisms by which they lead to disease. The review concludes with future research directions to fill this gap and some novel techniques with which to pursue these directions.

scholarly journals P0338CRUMBS HOMOLOG2-EZRIN SIGNALING INDUCED PODOCYTE INJURY, LEADING TO MINIMAL-CHANGE DISEASE(MCD) AND FOCAL SEGMENTAL GLOMERULOSCLEROSIS(FSGS)

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Ichiro Hada
Keyword(s):  
Electron Microscopy ◽  
Nephrotic Syndrome ◽  
Cell Line ◽  
Focal Segmental Glomerulosclerosis ◽  
Minimal Change Disease ◽  
Immunofluorescence Microscopy ◽  
Minimal Change ◽  
Podocyte Injury ◽  
Heavy Proteinuria ◽  
Foot Process

Abstract Background and Aims The etiology and cellular pathogenesis of podocyte injury leading to minimal-change disease (MCD) and focal segmental glomerulosclerosis (FSGS) remain largely obscure. Genetic mutation of crumbs homolog 2 (CRB2) is a cause of congenital nephrotic syndrome. Type-1 transmembrane proteins including CRB2 transduce outside-in signals that are involved in various cellular events including changes in the cytoskeletal network. The aim of the present study is to determine whether alteration of CRB2-mediated signaling in podocytes causes MCD and FSGS. Method Mice were immunized with a partial recombinant protein including the extracellular part of mouse CRB2. Urinalysis was obtained, and the kidney was subjected to histopathology. Kidney samples were also subjected to immunofluorescence microscopy and glomerular isolation to determine whether activation of the ezrin/radixin/moesin (ERM) family of cross-linkers between plasma membrane proteins and the actin cytoskeleton is involved in the pathogenesis of this nephrotic model. A CRB2-expressing mouse podocyte cell line was generated and incubated with anti-CRB2 antibody, and cell lysates were subjected to immunoblot analysis of ERM phosphorylation. The presence of anti-CRB2 antibody in the serum was determined by Western blot analysis. Results Apparent anti-CRB2 antibody was detected in the serum from 4 weeks onward. Immunized mice developed proteinuria at 4 weeks, which continued at least until 29 weeks. Mice developing extremely heavy proteinuria also developed hematuria from 18 weeks onward. Light microscopy revealed MCD in mice with proteinuria alone and FSGS in mice with heavy proteinuria and hematuria. Immunofluorescence microscopy revealed positive granular IgG staining in podocyte foot processes, but not complement C3. Electron microscopy and immuno-electron microscopy revealed alteration of actin organization associated with prominent foot process effacement. Strong phosphorylation of ezrin was observed in the glomerulus from the proteinuric stage and in the cellular lysates from the CRB2-expressing podocyte cell line incubated with anti-CRB2 antibody. Conclusion The current data revealed that binding of anti-CRB2 antibody to the extracellular domain of CRB2 on the podocyte foot process activated the ezrin-cytoskeleton network, leading to podocyte injury. Our data also indicated that signaling by this one molecular can induce two different phenotypes of glomerular injury: MCD and FSGS. In our model, the signaling was activated by anti-CRB2 antibody, but in patients with nephrotic syndrome the CRB2 ligands remain unknown. Therefore, it will be important to identify the soluble factors interacting with CRB2, which may be novel factors contributing to the pathogenesis of MCD and FSGS.

Pathogenesis of proteinuria in minimal change disease and focal segmental glomerulosclerosis

2018 ◽  
Author(s):  
Patrick Niaudet ◽  
Alain Meyrier
Keyword(s):  
Serum Albumin ◽  
Focal Segmental Glomerulosclerosis ◽  
Minimal Change Disease ◽  
Minimal Change ◽  
Slit Diaphragm ◽  
Segmental Glomerulosclerosis ◽  
Podocyte Loss ◽  
Glomerular Filtrate

It is now well established that the podocyte, and in particular the slit diaphragm structure, are critical to the barrier to serum albumin entering glomerular filtrate in large quantities. In minimal change disease there is proteinuria without podocyte death, whereas in focal segmental glomerulosclerosis there is not only podocyte dysfunction but also podocyte loss.

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