Disruption of the exocyst induces podocyte loss and dysfunction
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE127736 | GEO | 2019/03/02
REPOSITORIES: GEO
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Project description:Although the slit diaphragm proteins in podocytes are uniquely organized to maintain glomerular filtration assembly and function, little is known about the underlying mechanisms that participate in trafficking these proteins to the correct location for development and homeostasis. Identifying these mechanisms will likely provide novel targets for therapeutic intervention to preserve podocyte function following glomerular injury. Analysis of structural variation in cases of human nephrotic syndrome identified rare heterozygous deletions of EXOC4 in two patients. This suggested that disruption of the highly-conserved eight-protein exocyst trafficking complex could have a role in podocyte dysfunction. Indeed, mRNA profiling of injured podocytes identified significant exocyst down-regulation. To test the hypothesis that the exocyst is centrally involved in podocyte development/function, we generated homozygous podocyte-specific Exoc5 (a central exocyst component that interacts with Exoc4) knockout mice that showed massive proteinuria and died within 4 weeks of birth. Histological and ultrastructural analysis of these mice showed severe glomerular defects with increased fibrosis, proteinaceous casts, effaced podocytes, and loss of the slit diaphragm. Immunofluorescence analysis revealed that Neph1 and Nephrin, major slit diaphragm constituents, were mislocalized and/or lost. mRNA profiling of Exoc5 knockdown podocytes showed that vesicular trafficking was the most affected cellular event. Mapping of signaling pathways and Western blot analysis revealed significant up-regulation of the mitogen-activated protein kinase and transforming growth factor-β pathways in Exoc5 knockdown podocytes and in the glomeruli of podocyte-specific Exoc5 KO mice. Based on these data, we propose that exocyst-based mechanisms regulate Neph1 and Nephrin signaling and trafficking, and thus podocyte development and function.
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Project description:Disruption of the exocyst induces podocyte loss and dysfunction
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Project description:Kinase inhibitors (KIs) used in cancer therapeutics are associated with various side effects. One of the most significant adverse events that lead to discontinuation or modification of treatment is nephrotoxicity. We have identified BCR-ABL1 inhibitor dasatinib as a potential glomerular nephrotoxin due to its direct effect on podocyte biophysics. In order to understand the underlying molecular mechanisms used phospho-tyrosine enriched shotgun proteomics in immortalized mouse kidney podocytes treated with dasatinib.
2019-03-29 | PXD011761 | Pride
Project description:APOL1-miR193a axis participates in the preservation of molecular phenotype of differentiated podocytes (DPDs). We examined the hypothesis that APOL1 (G0) preserves, but APOL1 risk alleles (G1 and G2) disrupt APOL1-miR193a axis in DPDs. DPDG0s displayed down-regulation of miR193a, but upregulation of nephrin expression. DPDG1s/G2s exhibited an increase in miR193a and down-regulation of the expression of adherens complex's constituents (CD2AP, nephrin, and dendrin). DPDG0s showed decreased Cathepsin L, enhanced dynamin expressions, and the intact actin cytoskeleton. On the contrary, DPDG1s/G2s displayed an increase in Cathepsin L, but down-regulation of dynamin expressions and disorganization of the actin cytoskeleton. APOL1 silencing enhanced miR193a and Cathepsin L, but down-regulated dynamin expressions. DPDG1s/G2s displayed nuclear import of dendrin, indicating an occurrence of destabilization of adherens complexes in APOL1 risk milieu. These findings suggest that DPDG1s and DPDG2s developed disorganized actin cytoskeleton as a consequence of disrupted APOL1-miR193a axis. Interestingly, docking and co-labeling studies suggested an interaction between APOL1 and CD2AP. APOL1G1/G1 and APOL1G1/G2 transgenic mice displayed nuclear import of dendrin indicating destabilization of adherens complexes in podocytes; moreover, these mice showed a four-fold increase in urinary albumin to creatinine ratio and development of focal segmental glomerular lesions.
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Project description:The progression of proteinuric kidney disease is associated with podocyte loss but the mechanisms remain unclear. Podocytes reenter the cell cycle to repair damaged ds DNA breaks. However, unsuccessful repair results in podocytes crossing the G1/S checkpoint and undergoes abortive cytokinesis. In this study, we identified Pfn1 as a major contributor in maintaining glomerular integrity and its loss in mice results in severe proteinuria, and kidney failure due to podocyte mitotic catastrophe, characterized by abundant multinucleated cells. Reentry of podocytes were identified by using FUCCI-2aR mice, accompanying the alteration of cell-cycle associated proteins, such as P21, P53, Cyclin B, and Cyclin D. Podocyte-specific translating ribosome affinity purification (TRAP) and RNAseq revealed a reduction of Ribosomal RNA-processing protein 8 (Rrp8) and re-expression of Rrp8 partially rescued the in-vitro phenotype. Clinical analysis of patients with proteinuric kidney disease demonstrated multinucleated podocytes and reduced podocyte profilin1 in kidney tissue. These results suggest that profilin is indispensible in regulating podocyte cell cycle and its disruption contributes to podocyte loss through mitotic catastrophe.
2023-12-01 | GSE227414 | GEO
Project description:Podocyte injury is involved in the onset and progression of various kidney diseases. We previously demonstrated that the transcription factor, old astrocyte specifically induced substance (OASIS) in myofibroblasts, contributes to kidney fibrosis, as a novel role of OASIS in the kidneys. Importantly, we found that OASIS is also expressed in podocytes; however, the pathophysiological significance of OASIS in podocytes remains unknown. Upon lipopolysaccharide (LPS) treatment, there is an increase in OASIS in murine podocytes. Enhanced serum creatinine levels and tubular injury, but not albuminuria and podocyte injury, are attenuated upon podocyte-restricted OASIS knockout in LPS-treated mice, as well as diabetic mice. The protective effects of podocyte-specific OASIS deficiency on tubular injury are mediated by protein kinase C iota (PRKCI/PKCι), which is negatively regulated by OASIS in podocytes. Furthermore, podocyte-restricted OASIS transgenic mice show tubular injury and tubulointerstitial fibrosis, with severe albuminuria and podocyte degeneration. Finally, there is an increase in OASIS-positive podocytes in the glomeruli of patients with minimal change nephrotic syndrome and diabetic nephropathy. Taken together, OASIS in podocytes contributes to podocyte and/or tubular injury, in part through decreased PRKCI. The induction of OASIS in podocytes is a critical event for the disturbance of kidney homeostasis.
2022-06-22 | GSE206525 | GEO
Project description:Cosmc is an obligate chaperone for C1GalT1 T transferase necessary for generating mature mucin-type O-glycans. Animals lacking Cosmc in glomerular podocytes develop proteinuria, glomerulosclerosis and progressive renal failure. This study was designed to examine transcriptome differences in 1 month male animals with and without podocyte Cosmc, a time point when proteinuria is established but glomerular architecture is still relatively intact.
2019-03-04 | GSE126217 | GEO
Project description:The specialized glomerular epithelial cell (podocyte) of the kidney is a complex cell that is often damaged in glomerular diseases. Study of this cell type is facilitated by an in vitro system of propagation of conditionally immortalized podocytes. Here, genes that are differentially expressed in this in vitro model of podocyte differentiation are evaluated. Conditionally immortalized undifferentiated mouse podocytes were cultured under permissive conditions at 33*C. Podocytes that were differentiated at the non-permissive conditions at 37*C were used for comparison.
2010-08-28 | E-GEOD-23856 | biostudies-arrayexpress
Project description:The thorough characterization of the transcriptome of endogenous podocytes has been hampered by low yields of cell isolation procedures. Here we introduce a double fluorescent reporter mouse model combined with an optimized bead perfusion protocol and efficient single cell dissociation yielding more than 500,000 podocytes per mouse allowing for global, unbiased downstream applications. Combining mRNA transcriptional profiling revealed programs of highly specific gene regulation tightly controlling cytoskeleton, cell differentiation, endosomal transport and peroxisome function in podocytes. Strikingly, the analyses further predict that these podocyte-specific gene regulatory networks are accompanied by alternative splicing of respective genes. In summary, the presented M-bM-^@M-^XomicsM-bM-^@M-^Y approach will facilitate the discovery and integration of novel gene, protein and organelle regulatory networks that deepen our systematic understanding of podocyte biology. To compare gene expression of glomerulus podocytes versus non-podocytes 5 replicates of 4 pooled mice were used. Data were normalized by robust multi-chip analysis. Exon expression values were summarised to the core meta probesets, as defined by Affymetrix, using the oligo library from R.
2012-11-30 | E-GEOD-39441 | biostudies-arrayexpress
Project description:Podocytes are an integral part of the glomerular infiltration barrier. At present, many genes are known essential for podocyte survival and structural and functional homeostasis; however, there are more such genes to be uncovered. By single-cell RNA-seq of mouse podocytes, we detected the expression of gene encoding MCC regulator of WNT signaling pathway (MCC) in majority of the single podocytes and speculated that MCC may be essential for podocytes. We confirmed MCC expression in mouse podocytes and further showed its expression in human podocytes. To experimentally prove the essentiality of MCC for podocytes, we knocked down MCC in cultured podocytes, resulting in marked morphological change of cell shape, cytoskeletal stress fiber disruption, increased apoptosis, and downregulation of podocyte essential genes, CD2AP and WT1, demonstrating that MCC is essential for podocytes. To investigate the mechanism underlying the role of MCC in podocytes, we performed RNA-seq analysis of the podocytes in culture 24 hours after transfection of siRNA against MCC, followed by bioinformatics analysis of the genes with altered expression, and found some mechanistic clues. Lastly, we found that MCC is downregulated in podocytes treated with puromycin aminonucleosides and in glomeruli of diabetic mice and FSGS patients, implicating MCC in the development of podocytopathy and proteinuria. In conclusion, MCC is essential for podocytes and its deficiency may be involved in podocytopathy.
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