Changes in mouse kidney glomerular gene expression following dendrin knockout
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE47606 | GEO | 2014/05/20
SECONDARY ACCESSION(S): PRJNA206505
REPOSITORIES: GEO
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Project description:Glomerular podocyte cells are critical for the function of the renal ultrafiltration barrier. The highly specialized cell-cell junction of podocytes, the slit diaphragm, has a central role in the filtration barrier. Dendrin is a poorly characterized cytosolic component of the slit diaphragm in where it interacts with nephrin and Cd2ap. In this study, we have generated a dendrin knockout mouse line and explored the molecular interactions of dendrin. Dendrin-deficient mice were viable, fertile and had normal life span. To reveal the glomerular gene expression changes in the dendrin knockout mouse, Affymetrix Mouse Genome 430 2.0 Array were used to profiling the dendrin knockout and control glomeruli. Three dendrin knockout and three littermate control mice at age of 13 months were used to profile glomerular transcriptomes. Total glomerular RNA was extracted and hyrbridized on the Mouse Genome 430 2.0 Array according to standard procedures.
2014-05-20 | E-GEOD-47606 | biostudies-arrayexpress
Project description:Glomerular biology is dependent on tightly controlled signal transduction networks that control phosphorylation of signaling proteins such as cytoskeletal regulators or slit diaphragm proteins of kidney podocytes. Recent, in-depth analysis of the mouse glomerular phosphoproteome by tandem mass spectrometry confidently identified thousands of phosphorylation sites providing a unique opportunity to study signaling in vivo. However, the multitude of phosphorylated residues demands for additional systems biology approaches to separate physiologically important sites from non-functional phosphorylated residues. Cross-species comparison of phosphorylation events is a powerful mean to functionally prioritize and identify physiologically meaningful phosphorylation sites. Here, we present the result of additional phosphoproteomic analyses of the glomerular phosphoproteome in cow and rat to allow cross-species comparisons. We discovered several phosphorylation sites with potentially high biological relevance, e.g. tyrosine phosphorylation of the cytoskeletal regulator synaptopodin and the slit diaphragm protein neph-1 (Kirrel). Moreover, cross-species comparisons revealed conserved phosphorylation of the slit diaphragm protein nephrin on an acidic cluster at the intracellular terminus and conserved podocin phosphorylation on the very carboxyl terminus of the protein. Given the pivotal role of podocin for glomerular biology we studied a highly conserved podocin phosphorylation site in greater detail and show that phosphorylation regulates affinity of the interaction with nephrin and CD2AP. Taken together, these results suggest that species comparisons of phosphoproteomic data may reveal regulatory principles in glomerular biology.
2015-01-16 | PXD001005 | Pride
Project description:Background: Minimal change disease (MCD) and focal-segmental glomerulosclerosis (FSGS) are immune-mediated glomerular diseases manifesting as nephrotic syndrome. Autoantibodies against the podocyte slit diaphragm protein nephrin were recently identified in a subset of patients with minimal change disease, but their clinical and pathophysiological significance is largely unknown. Methods: Using immunoprecipitation assays, we performed a blinded screening for anti-nephrin antibodies in diagnostic and follow-up serum samples from adult patients with biopsy-proven MCD, FSGS, IgA nephropathy, and membranous nephropathy in comparison to healthy controls in two independent patient cohorts from Hamburg, Germany, and Bari, Italy. We further established a mouse model of anti-nephrin antibody-induced disease by active immunization using the recombinant murine nephrin ectodomain. Results: Anti-nephrin autoantibodies were detected in 50 of 110 (45%) patients with MCD, 8 of 107 (7%) patients with FSGS, 1 of 50 (2%) patients with membranous nephropathy, 0 of 48 (0%) patients with IgA nephropathy, and 0 of 67 (0%) healthy individuals. During follow-up, presence, and absence of anti-nephrin autoantibodies in patients with MCD and FSGS strongly correlated with active disease and remission, respectively. Immunization of mice induced anti-nephrin autoantibody formation and a highly dynamic phenotype with severe nephrotic syndrome and the histological features of MCD. Mechanistically, anti-nephrin autoantibodies induced nephrin phosphorylation at Tyr1191, cytoskeletal rearrangement, and downregulation of key podocyte proteins. Conclusion: Anti-nephrin antibodies are a valuable biomarker of disease activity in patients with MCD and FSGS, and binding of anti-nephrin antibodies at the podocyte slit diaphragm induces MCD with nephrotic syndrome.
2024-05-27 | PXD047417 | Pride
Project description:Background: Minimal change disease (MCD) and focal-segmental glomerulosclerosis (FSGS) are immune-mediated glomerular diseases manifesting as nephrotic syndrome. Autoantibodies against the podocyte slit diaphragm protein nephrin were recently identified in a subset of patients with minimal change disease, but their clinical and pathophysiological significance is largely unknown. Methods: Using immunoprecipitation assays, we performed a blinded screening for anti-nephrin antibodies in diagnostic and follow-up serum samples from adult patients with biopsy-proven MCD, FSGS, IgA nephropathy, and membranous nephropathy in comparison to healthy controls in two independent patient cohorts from Hamburg, Germany, and Bari, Italy. We further established a mouse model of anti-nephrin antibody-induced disease by active immunization using the recombinant murine nephrin ectodomain. Results: Anti-nephrin autoantibodies were detected in 50 of 110 (45%) patients with MCD, 8 of 107 (7%) patients with FSGS, 1 of 50 (2%) patients with membranous nephropathy, 0 of 48 (0%) patients with IgA nephropathy, and 0 of 67 (0%) healthy individuals. During follow-up, presence, and absence of anti-nephrin autoantibodies in patients with MCD and FSGS strongly correlated with active disease and remission, respectively. Immunization of mice induced anti-nephrin autoantibody formation and a highly dynamic phenotype with severe nephrotic syndrome and the histological features of MCD. Mechanistically, anti-nephrin autoantibodies induced nephrin phosphorylation at Tyr1191, cytoskeletal rearrangement, and downregulation of key podocyte proteins. Conclusion: Anti-nephrin antibodies are a valuable biomarker of disease activity in patients with MCD and FSGS, and binding of anti-nephrin antibodies at the podocyte slit diaphragm induces MCD with nephrotic syndrome.
2024-05-27 | PXD047421 | Pride
Project description:Heparan sulfate (HS) is an important component of the kidney anionic filtration barrier, the glomerular basement membrane (GBM). HS chains attached to proteoglycan protein cores are modified by sulfotransferases in a highly ordered series of biosynthetic steps resulting in immense structural diversity due to negatively charged sulfate modifications. 3-O-sulfation is the least abundant modification generated by a family of seven isoforms but creates the most highly sulfated HS domains. We analyzed the kidney phenotypes in the Hs3st3a1, Hs3st3b1 and Hs3st6 -knockout (KO) mice, the isoforms enriched in kidney podocytes. Individual KO mice show no overt kidney phenotype, although Hs3st3b1 kidneys were smaller than wildtype (WT). Furthermore, Hs3st3a1-/-; Hs3st3b1-/- double knockout (DKO) kidneys were smaller but also had a reduction in glomerular size relative to wildtype (WT). Mass spectrometry analysis of kidney HS showed reduced 3-O-sulfation in Hs3st3a1-/- and Hs3st3b1-/-, but not in Hs3st6-/- kidneys. Glomerular HS showed reduced HS staining and reduced ligand-and-carbohydrate engagement (LACE) assay, a tool that detects changes in binding of growth factor receptor-ligand complexes to HS. Interestingly, DKO mice have increased levels of blood urea nitrogen, although no differences were detected in urinary levels of albumin, creatinine and nephrin. Finally, transmission electron microscopy showed irregular and thickened GBM and podocyte foot process effacement in the DKO compared to WT. Together, our data suggest that loss of 3-O-HS domains disrupts the kidney glomerular architecture without affecting the glomerular filtration barrier and overall kidney function.
2024-07-05 | GSE261059 | GEO
Project description:The most common genetic causes of steroid-resistant nephrotic syndrome (SRNS) are mutations in the NPHS2 gene, which encodes the lipid-binding protein podocin. Mass spectrometry and cDNA sequencing revealed the existence of a second shorter isoform in the human kidney in addition to the well-studied canonical full-length protein. Distinct subcellular localization of the shorter isoform that lacks part of the conserved PHB domain suggested a physiological role. Here we analyzed whether this protein can substitute for the canonical full-length protein. The short isoform of podocin is not found in other organisms except humans. We therefore now analysed a mouse line expressing the equivalent podocin isoform (podocinΔexon5) by CRISPR/Cas-mediated genome editing. We characterized the phenotype of these mice expressing podocinΔexon5 and used targeted mass spectrometry and qPCR to compare protein and RNA levels of podocinwildtype and podocinΔexon. After immunolabeling slit diaphragm components, STED microscopy was applied to visualize alterations of the podocytes’ foot process morphology. Mice homozygous for podocinΔexon5 were born heavily albuminuric and did not survive past the first 24 hours after birth. Targeted mass spectrometry revealed massively decreased protein levels of podocinΔexon5, whereas RNA abundance was not different from the canonical form of podocin. STED microscopy revealed the complete absence of podocin at the podocytes’ slit diaphragm and severe morphological alterations of podocyte foot processes. Mice heterozygous for podocinΔexon5 were phenotypically and morphologically unaffected despite decreased podocin and nephrin protein levels.The murine equivalent to the human short isoform of podocin cannot stabilize the lipid-protein complex at the podocyte slit diaphragm. Reduction of podocin levels at the site of the slit diaphragm complex has a detrimental effect on podocyte function and morphology. It is associated with decreased protein abundance of nephrin, the central component of the filtration-slit forming slit diaphragm protein complex.
2023-12-20 | PXD041055 | Pride
Project description:Renal blood filtration occurs in a functional unit called the glomerulus. The resident cell types comprise the filtration barrier, namely podocytes, mesangial cells and glomerular endothelial cells. Here we introduce a glomerular cell isolation protocol, which enables the separation of these three cell types in sufficient amounts and purity to allow detailed protein-biochemical investigations. We demonstrate that the expression of fluorescent transgenes in glomerular cells can result in proteome artifacts. We show that different mouse strains have different glomerular cell type proteomes. Further, we demonstrate the power of the technique to identify new glomerular cell type-enriched proteins and demonstrate the potential of this globally applicable technique in the dissection of cell-specific disease responses and intra-glomerular cell-type crosstalk.
2021-11-12 | PXD024481 | Pride
Project description:Podocytes are cells of the visceral epithelium in the kidneys and form a crucial component of the glomerular filtration barrier, contributing to size selectivity and maintaining a massive filtration surface. We are interested in pursuing a microarray analysis to identify the glycosylation-related genes that are modulated in podocytes during insulin and glucose stimulation. As such, we propose to isolate RNA from cultured AB 8/13 human podocyte cell line in their normal state and treated with different concentrations of insulin and glucose. Initially, we would like to analyze 12 samples (Normal control, 2 Starved controls, Insulin experiments 1-4, and glucose experiments 1-5). These experiments would give us information on the gene regulation changes in different healthy and diabetic conditions. In addition to providing possible identification of the unknown proteins involved with diabetic nephropathy, such analysis would provide novel information about early responses by podocytes in response to insulin and glucose level changes in vitro. The results from this analysis will be utilized to focus our research with regard to glycosylation of the proteins in the podocyte slit diaphragm.
2011-10-02 | E-GEOD-32553 | biostudies-arrayexpress
Project description:Podocytes are the highly specialised cells within the glomeruli of the kidney that maintain the filtration barrier by forming interdigitating foot processes and slit-diaphragms. Disruption to these features result in proteinuria. Studies into podocyte biology and disease has been hampered by a paucity of in vitro models of this non-proliferative cell type. Here we characterise sieved glomeruli from kidney organoids derived from human pluripotent stem cells. Compared to conditionally immortalised podocytes, organoid-derived glomeruli show superior podocyte-specific gene and protein expression, morphology and functional properties. Using CRISPR-derived MAFB reporter iPSC lines, homozygous MAFB mutant organoids recapitulated the anticipated disease related transcriptional changes. Culture of kidney organoids on chicken chorioallantoic membrane resulted in glomerular vascularisation, glomerular filtration barrier assembly, formation of slit diaphragms and fenestrated endothelial cells. This definitively demonstrates that human iPSC kidney organoid-derived glomeruli can serve as an accurate model of human podocytopathies and glomerular disease in vitro.
2018-12-04 | GSE99583 | GEO
Project description:The filtration of blood in the kidney which is crucial for mammalian life is determined by the slit-diaphragm (SD), a proteinaceous junction between the foot processes of renal podocytes. Based on studies of structure and function the SD has been hypothesized to operate as a final barrier or as a ‘molecular sensor’ of renal filtration. Using high-resolution proteomic analysis of SDs affinity-isolated from rodent kidney, we show that the native SD is built from the known junction-forming components Nephrin, Neph1 and Podocin and a co-assembled high-molecular weight network of proteins. The network constituents cover distinct classes of proteins including signaling receptors, kinases and phosphatases, transporters and scaffolds. Knock-out or knock-down of either the core components or the selected network constituents tyrosine kinase MER (MERTK), atrial natriuretic peptide receptor C (ANPRC) and protein ITM2B resulted in target-specific impairment or disruption of the filtration process. Thus, our results identify the SD as a multi-component system that is endowed with context-dependent dynamics via a co-assembled protein network.
2022-09-20 | PXD034356 | Pride