Elucidation of Novel Mechanisms of Diabetes-Related Podocyte Dysfunction Using scRNA-seq

Background: Diabetic nephropathy is a principal cause of kidney failure, with persistent proteinuria despite current therapies. Podocyte injury is central to its pathogenesis, and uncovering its mechanisms is key to identifying new therapeutic targets. This study was designed to identify a novel therapeutic target for protecting podocytes in diabetes using scRNAseq. Methods: To enrich glomerular cell populations, glomeruli were isolated from 17-week-old db/db mice (a model of obesity-induced type 2 diabetes) and age-matched db/m control mice. scRNA-seq was performed on the isolated glomeruli. Data were analyzed using the Seurat package for clustering and differential gene expression analysis. Results: Cluster analysis identified four major glomerular cell populations: podocytes, glomerular endothelial cells, mesangial cells, and immune cells. The proportion of podocytes was significantly reduced in db/db mice (12.6%, 733/5,822 cells) compared to db/m controls (39.9%, 2,593/6,503 cells). Differential expression analysis within the podocyte cluster revealed 268 upregulated and 137 downregulated genes in db/db mice. Thirteen genes (2 upregulated and 11 downregulated) showing the most significant changes were selected for validation. Gene expression changes identified by scRNA-seq were validated in human immortalized podocytes exposed to diabetes-related stimuli (high glucose, palmitic acid, TNF-α, and TGF-β). Among the genes, OPCML, LAPTM4B, RBM3, and IQGAP1 were significantly upregulated by palmitic acid, while TGF-β downregulated HSPA1B and HSP90AB1, consistent with the scRNA-seq findings. Conclusion: We identified six genes whose expression was consistently altered under diabetic conditions both in vivo and in vitro, representing potential therapeutic targets for diabetic nephropathy.