Single-Cell RNA Profiling Changes in Glomerular Cells in Diabetic Nephropathy (DN)

Hyperglycemia, the main risk factor for DN, causes complex pathological damages in glomeruli. To characterize detail changes in cell differentiation and gene expressions induced by diabetes, we performed unbiased single-cell RNA sequencing (scRNA-seq) on glomerular cells from diabetic and nondiabetic mice of long duration. Glomerular cells were isolated from C57 mice after 7-months of STZ-induced diabetes, when clear glomerular pathologies have been documented. Total number of 48,337 high-qualitied glomerular cells were isolated and sequenced from WT and STZ-treated mice. Based on clustering analysis and cell-type specific markers, 12 different cell types were identified, including endothelial cells (EC), podocytes, mesangial cells (MC), proximal tubule cells, parietal epithelial cells (PEC), collecting duct cells, ascending loop of Henle, macrophages, B cells, T cells, NK cells and neutrophils. Over 90% of the cells were from glomeruli (41% EC, 34 % podocytes, 14% MC, 2% of PEC), and 6% immune cells. Interestingly, gene profiling identified 9 clusters of EC, 5 clusters of MC and 7 clusters of podocytes. Diabetes did not change the total cell numbers for EC, MC and podocytes, although macrophage and B cell numbers were increased from 2.2% to 4.8% and 0.35% to 1%, respectively. Cluster subset analysis of EC, MC and podocytes showed that diabetes induced substantial changes. For podocytes, diabetes increased those clusters (5% to 37%) with high expressions of stressed proteins such as Hspa1a, Hspa1b and Hsp90aa1, while decreased those clusters with high expressions of ECM production and CDC42 GTPase cycle, that were involved in cytoskeleton stabilization and foot process formation. Findings from scRNA-seq of glomeruli showed there were multiple subsets of podocytes, EC and MC, which appear to have different functions and their distributions were changed by diabetes. Understanding the mechanism for the distribution changes of the subsets may provide new insight in the pathogenesis of DN. Disclosure J. Fu: None. Q. Li: None. K. Park: None. Q. Huang: None. I. Wu: None. G.L. King: Research Support; Janssen Research & Development, LLC.