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: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:Background: Recent single-cell RNA sequencing (scRNA-seq) analyses have offered much insight into cell-specific gene expression profiles in normal kidneys. However, in diseased kidneys, understanding of changes in specific cells, particularly glomerular cells, remains limited. Methods: To elucidate the glomerular cell–specific gene expression changes in diabetic kidney disease, we performed scRNA-seq analysis of isolated glomerular cells from streptozotocin-induced diabetic endothelial nitric oxide synthase (eNOS)–deficient (eNOS-/-) mice and control eNOS-/- mice. Results: We identified five distinct cell populations, including glomerular endothelial cells, mesangial cells, podocytes, immune cells, and tubular cells. Using scRNA-seq analysis, we confirmed the expression of glomerular cell–specific markers and also identified several new potential markers of glomerular cells. The number of immune cells was significantly higher in diabetic glomeruli compared with control glomeruli, and further cluster analysis showed that these immune cells were predominantly macrophages. Analysis of differential gene expression in endothelial and mesangial cells of diabetic and control mice showed dynamic changes in the pattern of expressed genes, many of which are known to be involved in diabetic kidney disease. Moreover, gene expression analysis showed variable responses of individual cells to diabetic injury. Conclusion: Our findings demonstrate the ability of scRNA-seq analysis in isolated glomerular cells from diabetic and control mice to reveal dynamic changes in gene expression in diabetic kidneys, with variable responses of individual cells. Such changes, which might not be apparent in bulk transcriptomic analysis of glomerular cells, may help identify important pathophysiologic factors contributing to the progression of diabetic kidney disease.
Project description:Murine models have been valuable instruments in defining the pathogenesis of diabetic nephropathy (DN), but they only partially recapitulate disease manifestations of human DN, limiting their utility . In order to define the molecular similarities and differences between human and murine DN, we performed a cross-species comparison of glomerular transcriptional networks. Glomerular gene expression was profiled in patients with early type 2 DN and in three mouse models (streptozotocin DBA/2 mice, db/db C57BLKS, and eNOS-deficient C57BLKS db/db mice). Species-specific transcriptional networks were generated and compared with a novel network-matching algorithm. Three shared, human-mouse cross-species glomerular transcriptional networks containing 143 (Human-STZ), 97 (Human- db/db), and 162 (Human- eNOS-/- db/db) gene nodes were generated. Shared nodes across all networks reflected established pathogenic mechanisms of diabetic complications, such as elements of JAK-STAT and VEGFR signaling pathways . In addition, novel pathways not formally associated with DN and cross-species gene nodes and pathways unique to each of the human-mouse networks were discovered. The human-mouse shared glomerular transcriptional networks will assist DN researchers in the selection of mouse models most relevant to the human disease process of interest. Moreover, they will allow identification of new pathways shared between mice and humans. We used microarrays to analyze the transcriptome of three different diabetic mouse models Glomerular RNA was extracted using the RNeasy Mini Kit and processed for hybridization on Affymetrix GeneChip Mouse Genome 430 2.0 microarrays.
Project description:Comparing glomerular gene expression level between mice with different susceptibilities to diabetic nephropathy, DBA/2 (susceptible) and C57BL/6 (resistant) mice, respectively. The hypothesis is that differential expression of glomerular genes regulate susceptibility to diabetic nephropathy. The results show immune related genes. Thus, glomerular inflammation may increase susceptibility to diabetic nephropathy in mice. RNA isolated from kidney glomeruli of DBA/2 and C57BL/6 mice, with or without 4 weeks diabetes induced by streptozotocin.
Project description:Murine models have been valuable instruments in defining the pathogenesis of diabetic nephropathy (DN), but they only partially recapitulate disease manifestations of human DN, limiting their utility . In order to define the molecular similarities and differences between human and murine DN, we performed a cross-species comparison of glomerular transcriptional networks. Glomerular gene expression was profiled in patients with early type 2 DN and in three mouse models (streptozotocin DBA/2 mice, db/db C57BLKS, and eNOS-deficient C57BLKS db/db mice). Species-specific transcriptional networks were generated and compared with a novel network-matching algorithm. Three shared, human-mouse cross-species glomerular transcriptional networks containing 143 (Human-STZ), 97 (Human- db/db), and 162 (Human- eNOS-/- db/db) gene nodes were generated. Shared nodes across all networks reflected established pathogenic mechanisms of diabetic complications, such as elements of JAK-STAT and VEGFR signaling pathways . In addition, novel pathways not formally associated with DN and cross-species gene nodes and pathways unique to each of the human-mouse networks were discovered. The human-mouse shared glomerular transcriptional networks will assist DN researchers in the selection of mouse models most relevant to the human disease process of interest. Moreover, they will allow identification of new pathways shared between mice and humans. We used microarrays to analyze the transcriptome of three different diabetic mouse models
Project description:Endothelial dysfunction promotes the pathogenesis of diabetic nephropathy (DN), which is considered to be an early event in disease progression. However, the molecular changes associated with glomerular endothelial cell (GEC) injury in early DN are not well defined. Most gene expression studies have relied on the indirect assessment of GEC injury from isolated glomeruli or renal cortices. Here, we present transcriptomic analysis of isolated GECs, using streptozotocin-induced diabetic wildtype (STZ-WT) and diabetic eNOS-null (STZ-eNOS−/−) mice as models of mild and advanced DN, respectively. GECs of both models in comparison to their respective nondiabetic controls showed significant alterations in the regulation of apoptosis, oxidative stress, and proliferation. The extent of these changes was greater in STZ-eNOS−/− than in STZ-WT GECs. Additionally, genes in STZ-eNOS−/− GECs indicated further dysregulation in angiogenesis and epigenetic regulation. Moreover, a biphasic change in the number of GECs, characterized by an initial increase and subsequent decrease over time, was observed only in STZ-eNOS−/− mice. This is consistent with an early compensatory angiogenic process followed by increased apoptosis, leading to an overall decrease in GEC survival in DN progression. From the genes altered in angiogenesis in STZ-eNOS−/− GECs, we identified potential candidate genes, Lrg1 and Gpr56, whose function may augment diabetes-induced angiogenesis. Thus, our results support a role for GEC in DN by providing direct evidence for alterations of GEC gene expression and molecular pathways. Candidate genes of specific pathways, such as Lrg1 and Gpr56, can be further explored for potential therapeutic targeting to mitigate the initiation and progression of DN.
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:Purpose:Renal injury with the loss of podocyte was characteristic pathology of diabetic nephropathy (DN) and correlated with increased albuminuria. Many studies have found the nephroprotective effect of the novel inhibitors of sodium-glucose cotransporter 2 (SGLT2-is), like Dapagliflozin, delaying the progression of DN. However, the underlying mechanisms of SGLT2 associated with podocyte injury are still not fully elucidated. Methods: Through mRNA sequencing, streptozotocin-induced and Dapagliflozin-intraperitoneal injection mice models were established to explore potential mechanism between Dapagliflozin and renal phenotype. And all changes referring this observed pathway were proven repeatedly in podocyte. Results: Here, we generated the streptozotocin-induced DN models and found the accumulation of nephrotoxin and pathological lesions of the kidney, including interstitial inflammatory infiltration, mesangial expansion and glomerular sclerosis, while low expression of SGLT2 mitigated these injuries in Dapagliflozin-treated mice. Moreover, mRNA expression profile in these treated models determined the significance of insulin-like growth factor-1 receptor (IGF1R)/PI3K regulatory axis in glomerular injury. Particularly, SGLT2-is inhibited the increase of mesenchymal marker, α-SMA and the decrease of podocyte marker, nephrin at the gene or protein level. KEGG analysis also showed the enrichment of phosphatidylinositol signaling system and TGF-β/smad pathway. In parallel, the protein level of IGF1R, phosphorylated PI3K, and α-SMA were increased in high-glucose stimulated human podocyte, and reduced in Dapagliflozin (50nM and 100nM) or OSI-906 (inhibitor of IGF1R, 60nM) used groups. Notably, combination of the two inhibitors produced an accumulative effect in the protection of podocyte integrity. Mechanistically, IGF1 or IGF2 could bind to IGF1 receptors to mediate the epithelial-mesenchymal transition (EMT) of diabetic podocyte in response to the upregulation of SGLT2. Indeed, we enrolled the urine and plasma samples from a cohort consisting of 13 healthy people, and a cohort of 19 patients with DN using SGLT2-inhibitors (n=9) or not (n=10). Compared with pure DN patients, Elisa results suggested an increased circulation and excretion level of IGF1/2 in SGLT2-is used DN cohort. Conclusions: Taken together, our study reported the key role of SGLT2/IGF1R/PI3K signaling in regulating podocyte EMT. Modulating the IGF1R expression may provide a novel idea for DN therapy.
Project description:To investigate dynamic changes in glomerular cells, including podocyte, mesangial cells and glomerular endothelial cells, in the development of diabetic nephropathy We then performed gene expression profiling analysis using data obtained from RNA-seq of glomerular cells of control(m/m), diabetic (db-/- 6-week-old) and diabetic nephropathy (db-/- 10-week-old with albuminuria) mice