Project description:Cellular senescence is associated with the progression of diabetic kidney disease (DKD), and accelerated podocyte senescence promotes the pathogenesis of renal damage. We found that GPR124 was reduced in cultured human podocytes treated with high glucose (HG).To further clarify the role of GPR124 in podocytes, we overexpressed GPR124 via plasmid-harboring adenovirus infection. By RNA sequencing analysis of podocytes with different treatment, we observed GPR124 overexpression significantly affected several kinds of cell adhesion.
Project description:Podocytes form filtration barrier through foot process around glomerualar basement membrane and selectively permit permeability of molecular smaller than albumin. Diabetes can cause podocyte pathological changes leading to high urine albumin level. Diabetic mouse model OVE26 has extremly high urine albumin and previously studies indicated its podocyte damaged. Here we try to find the key genes change in OVE26 diabetic mouse model podocyte by microarray assay while normal FVB mouse podocyte set as control. Podocyte eGFP transgenic mice were made on FVB background and crossbred to OVE26 diabetic model. Glomeruli isolated from OVE-GFP mice were digested by trypsin into signal cell. Podocytes with GFP were sorting out by FACS.
Project description:Podocytes form filtration barrier through foot process around glomerualar basement membrane and selectively permit permeability of molecular smaller than albumin. Diabetes can cause podocyte pathological changes leading to high urine albumin level. Diabetic mouse model OVE26 has extremly high urine albumin and previously studies indicated its podocyte damaged. Here we try to find the key genes change in OVE26 diabetic mouse model podocyte by microarray assay while normal FVB mouse podocyte set as control.
Project description:We compared mRNA profiles of isolated glomeruli versus sorted podocytes between diabetic and control mice. IRG mice crossed with eNOS-/- mice were further bred with podocin-rTTA and TetON-Cre mice to permanently label podocytes before the diabetic injury. Diabetes was induced by injection of streptozotocin. mRNA profiles of isolated glomeruli and sorted podocytes from diabetic and control mice at 10 weeks after induction of diabetes were examined. Consistent with the previous reports, expression of podocyte-specific markers in the glomeruli were down-regulated in the diabetic mice compared to controls. However, these differences disappeared when mRNA levels were corrected for podocyte number per glomerulus. Interestingly, the expression of these markers was not altered in sorted podocytes from diabetic mice, suggesting that the reduced expression of podocyte markers in isolated glomeruli is likely a secondary effect of reduced podocyte number, rather than the loss of differentiation markers. Analysis of the differentially expressed genes in diabetic mice also revealed distinct up-regulated pathways in the glomeruli (mitochondrial function and oxidative stress) and podocytes (actin organization). In conclusion, our data suggest that podocyte-specific gene expression in transcriptome obtained from the whole glomeruli may not represent those of podocytes in the diabetic kidney. We compared mRNA profiles of isolated glomeruli versus sorted podocytes between diabetic and control mice.
Project description:Podocyte injury in diabetic kidney disease contributes to the development of albuminuria and subsequent renal decline. Clinically, gastric bypass surgery is associated with reductions in albuminuria, and rodent studies demonstrate coherent improvements in renal histology. We aimed to investigate the mechanisms underpinning remission of albuminuria following gastric bypass focussing on podocyte injury. Firstly, we tracked the evolution of albuminuria and cognate evidence of histological and ultrastructural damage to the glomerulus in male Zucker Diabetic Fatty rats. Secondly, we examined the impact of gastric bypass in these rats, focussing on podocyte injury. Thirdly, we conducted a global transcriptomic study profiling the shift in the renal transcriptome in the Zucker Diabetic Fatty rats rat and its relevance to human disease. Lastly, we explored whether gastric bypass could reverse the changes seen in the disease associated transcriptome. Albuminuria in the Zucker Diabetic Fatty rat developed by 12 weeks of age. This was accompanied by glomerulomegaly, podocyte stress and ultrastructural evidence of podocyte dedifferentiation. When animals underwent gastric bypass at 12 weeks of age, marked reductions in albuminuria in association with normalisation of glomerular tuft size, attenuation of podocyte stress and improvements in podocyte foot process morphology were observed within 2 months of surgery. A characteristic disease associated gene expression signature was observed in the kidneys of Zucker Diabetic Fatty rats, with a core set of alterations conserved in global analysis of the human DKD transcriptome. Many of the shared gene expression alterations were reversed by gastric bypass. Reductions in podocyte injury represent a key mechanism underpinning the remission of albuminuria following gastric bypass.
Project description:We compared mRNA profiles of isolated glomeruli versus sorted podocytes between diabetic and control mice. IRG mice crossed with eNOS-/- mice were further bred with podocin-rTTA and TetON-Cre mice to permanently label podocytes before the diabetic injury. Diabetes was induced by injection of streptozotocin. mRNA profiles of isolated glomeruli and sorted podocytes from diabetic and control mice at 10 weeks after induction of diabetes were examined. Consistent with the previous reports, expression of podocyte-specific markers in the glomeruli were down-regulated in the diabetic mice compared to controls. However, these differences disappeared when mRNA levels were corrected for podocyte number per glomerulus. Interestingly, the expression of these markers was not altered in sorted podocytes from diabetic mice, suggesting that the reduced expression of podocyte markers in isolated glomeruli is likely a secondary effect of reduced podocyte number, rather than the loss of differentiation markers. Analysis of the differentially expressed genes in diabetic mice also revealed distinct up-regulated pathways in the glomeruli (mitochondrial function and oxidative stress) and podocytes (actin organization). In conclusion, our data suggest that podocyte-specific gene expression in transcriptome obtained from the whole glomeruli may not represent those of podocytes in the diabetic kidney.
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.
Project description:Overexpression of glomerular JAK2 mRNA specifically in glomerular podocytes of 129S6 mice led to significant increases in albuminuria, mesangial expansion, glomerulosclerosis, glomerular fibronectin accumulation, and glomerular basement membrane thickening as well as a significant reduction in podocyte density in diabetic mice. Treatment with a specific JAK1/2 inhibitor partly reversed the major phenotypic changes of DKD
Project description:Podocyte injury is a major determinant in proteinuric kidney disease and identification of potential therapeutic targets for preventing podocyte injury has clinical importance. Here, we show that histone deacetylase Sirt6 protects against podocyte injury through epigenetic regulation of Notch signaling. Sirt6 is downregulated in renal biopsies from patients with podocytopathies and its expression negatively correlates withglomerular filtration rate. Podocyte-specific deletion of Sirt6 exacerbates podocyte injury and proteinuria in two independent mouse models including diabetic nephropathy and adriamycin-induced nephropathy. Sirt6 has pleiotropic protective actions in podocytes including anti-inflammatory and anti-apoptotic effects, is involved in actin cytoskeleton maintenance, and promotes autophagy. Sirt6 also reduces urokinase plasminogen activator receptor expression, which is a key factor for podocyte foot process effacement and proteinuria. Mechanistically, Sirt6 inhibits Notch1 and Notch4 transcription by deacetylating the histone H3K9. We suggest Sirt6 as a potential therapeutic target in proteinuric kidney disease.