Single-nucleus transcriptome profiling provides insights into the pathophysiology of OSA-related renal injury

Obstructive sleep apnea (OSA) has been demonstrated to be associated with renal injury. However, the cellular and molecular mechanisms by which chronic intermittent hypoxia (CIH), a hallmark of OSA, contributes to renal injury remain poorly understood. Twelve male Sprague-Dawley rats were randomized into normoxic control (NC) and CIH groups (n = 6 each), with CIH exposure for 12 weeks. Renal injury was evaluated by Hematoxylin and Eosin staining and a modified Jablonski score. Single-nucleus RNA sequencing (snRNA-seq) was performed. Data analysis included clustering of cells, differential gene expression analysis, and functional enrichment through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Histopathological analysis revealed renal injury with renal tubular epithelial cell edema, necrosis in the CIH group compared to NC. A total of 42,581 cells (19,655 cells from NC group and 22,926 cells from CIH group) were retained after quality control, with 13 distinct renal cell populations identified. CIH exposure resulted in an increased proportion of podocytes, while mesangial cells were reduced compared to the NC group. CIH exposure altered the transcriptomic landscape, with differentially expressed genes (DEGs) observed across multiple cell types. Functional enrichment analysis indicated that CIH-induced DEGs were associated with suppressed metabolic and signaling pathways in proximal tubule and loop of Henle epithelial cells, activation of apoptotic and sodium reabsorption pathways in distal convoluted tubule cells, and enhanced inflammatory and phagocytic signaling in mononuclear phagocytes. Our study provides a high-resolution atlas of CIH-induced transcriptional changes in the rat kidney. The findings reveal cell type-specific responses and pathways potentially contributing to OSA-associated renal injury, offering novel insights into pathogenesis and potential therapeutic targets for preventing renal damage in OSA patients.