ABSTRACT: Glomerular diseases are most common cause of end stage kidney disease (ESKD). Although renin angiotensin system inhibitors are effective for progression of chronic kidney disease, The number of ESKD increases in the world. To identify a new candidate drug for glomerular disease, differentially expressed genes are searched by glomerular RNA microarray.
Project description:The role of the renin-angiotensin system in chronic kidney disease involves multiple peptides and receptors. Exerting antipodal pathophysiological mechanisms, renin inhibition and AT1 antagonism ameliorate renal damage. This is a comparison between the renin inhibitor aliskiren with the At1 antagonist losartan in mice with chronic kidney disease due to renal ablation.
Project description:The role of the renin-angiotensin system in chronic kidney disease involves multiple peptides and receptors. Exerting antipodal pathophysiological mechanisms, renin inhibition and AT1 antagonism ameliorate renal damage. This is a comparison between the renin inhibitor aliskiren with the At1 antagonist losartan in mice with chronic kidney disease due to renal ablation. Renal tissue from ablated mice was used after 6-week treatment with either 500 mg/l losartan or 50 mg/kg aliskiren per day (n = 5)
Project description:The pathogenic mechanisms of common kidney glomerular diseases, including the vast majority of cases of proteinuria, remain unknown. To gain insight into the pathogenesis of proteinuria development, we characterized the glomerular gene expression changes that accompany early stages of proteinuria induced by lipopolysaccharide (LPS) in mice.
Project description:Diabetic nephropathy (DN) is a leading cause of ESRD worldwide, but its molecular pathogenesis is not well-defined and there are no specific treatments. In humans, there is a strong genetic component determining susceptibility to DN. However, specific genes controlling DN susceptibility in humans have not been identified. Here we describe a new mouse model, combining type 1 diabetes with activation of the renin angiotensin system (RAS), which develops robust kidney disease with features resembling human DN: heavy albuminuria, hypertension and glomerulosclerosis. Additionally, there is a powerful effect of genetic background regulating susceptibility to nephropathy. The 129 strain is susceptible to kidney disease, whereas the C57BL/6 strain is resistant. To examine the molecular basis of this differential susceptibility, we analyzed the glomerular transcriptome of young mice with albuminuria but without detectable alterations in glomerular structure. We find dramatic difference in regulation of immune and inflammatory pathways with up-regulation of pro-inflammatory pathways in the susceptible (129) strain and coordinate down-regulation in the resistant (C57BL/6) strain, compared to their respective baselines. Many of these pathways were also up-regulated in a rat model and in humans with DN. Our studies suggest that genes controlling inflammatory responses, triggered by hyperglycemia and hypertension, may be critical early determinants of susceptibility to DN. The analysis was carried out on 2 strains of mice (129/SvEv and C57BL/6), each involving 2 genotypes (wild-type and RenTg/Ins2Akita mutations). Four replicates were used for each strain-genotype (with the exception of 129/SvEv wild-type mice, which had 3 replicates).
Project description:The pathogenic mechanisms of common kidney glomerular diseases, including the vast majority of cases of proteinuria, remain unknown. To gain insight into the pathogenesis of proteinuria development, we characterized the glomerular gene expression changes that accompany early stages of proteinuria induced by lipopolysaccharide (LPS) in mice. Nine-week-old female C57Bl6 mice were allocated to LPS-treated group (n=6) or PBS control group (n=4), and subsequently treated either by a single intraperitoneal injection LPS or control buffer.
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.
Project description:While blocking the renin angiotensin aldosterone system (RAAS) has been the main therapeutic strategy to control diabetic kidney disease (DKD) for many years, 25-30% of diabetic patients still develop the disease. In the present work we adopted a system biology strategy to analyze glomerular protein signatures to identify drugs with potential therapeutic properties in DKD acting through a RAAS-independent mechanism. Glomeruli were isolated from wild type and type 1 diabetic mice (Ins2Akita) treated or not with the angiotensin-converting enzyme inhibitor (ACEi) ramipril. Ramipril efficiently reduced the urinary albumin/creatine ratio (ACR) of Ins2Akita mice without modifying DKD-associated renal-injuries. Large scale quantitative proteomics was used to identify the DKD-associated glomerular proteins (DKD-GPs) that were ramipril-insensitive (RI-DKD-GPs). We then applied an in silico drug repurposing approach using a pattern-matching algorithm (Connectivity Mapping) to compare the RI-DKD-GPs’s signature with a collection of thousands of transcriptional signatures of bioactive compounds. The sesquiterpene lactone parthelonide was identified as one of the top compounds predicted to reverse the RI-DKD-GPs’s signature. Treatment of diabetic Ins2Akita mice with dimethylaminoparthenolide (DMAPT), a water soluble analogue of parthenolide, significantly reduced urinary ACR. However, in contrast to ramipril, DMAPT also significantly reduced glomerulosclerosis and tubulointerstitial fibrosis. Using a system biology approach we identified DMAPT, as a compound with a potential add-on value to standard-of-care ACEi-treatment in DKD.
Project description:Three different cell types constitute the glomerular filter: mesangial cells, endothelial cells, and podocytes. As yet, it remains unknown to what extent cellular heterogeneity exists within healthy glomerular cell populations. Here, we used nanodroplet-based, highly parallel transcriptional profiling to characterize the cellular content of purified wildtype mouse glomeruli. Unsupervised clustering of 13,000 single-cell transcriptomes identified the three known glomerular cell types. We provide a comprehensive online atlas of gene expression in glomerular cells, which can be queried and visualized using an interactive and freely available database. Novel marker genes for all glomerular cell types were identified and supported by immunohistochemistry stainings obtained from the Human Protein Atlas. Subclustering of glomerular endothelial cells revealed a subset of activated endothelium, expressing marker genes related to endothelial proliferation. Additionally, the podocyte population could be divided in three different subclusters. In conclusion, our study comprehensively characterizes gene expression in individual glomerular cells and sets the stage for the dissection of glomerular function at the single-cell level in health and disease.
Project description:Diabetic nephropathy (DN) is a leading cause of ESRD worldwide, but its molecular pathogenesis is not well-defined and there are no specific treatments. In humans, there is a strong genetic component determining susceptibility to DN. However, specific genes controlling DN susceptibility in humans have not been identified. Here we describe a new mouse model, combining type 1 diabetes with activation of the renin angiotensin system (RAS), which develops robust kidney disease with features resembling human DN: heavy albuminuria, hypertension and glomerulosclerosis. Additionally, there is a powerful effect of genetic background regulating susceptibility to nephropathy. The 129 strain is susceptible to kidney disease, whereas the C57BL/6 strain is resistant. To examine the molecular basis of this differential susceptibility, we analyzed the glomerular transcriptome of young mice with albuminuria but without detectable alterations in glomerular structure . We find dramatic difference in regulation of immune and inflammatory pathways with up-regulation of pro-inflammatory pathways in the susceptible (129) strain and coordinate down-regulation in the resistant (C57BL/6) strain, compared to their respective baselines. Many of these pathways were also up-regulated in a rat model and in humans with DN. Our studies suggest that genes controlling inflammatory responses, triggered by hyperglycemia and hypertension, may be critical early determinants of susceptibility to DN.