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.阻塞性睡眠呼吸暂停（Obstructive Sleep Apnea, OSA）已被证实与肾损伤存在关联。然而，作为OSA标志性病理特征的慢性间歇性缺氧（Chronic Intermittent Hypoxia, CIH）介导肾损伤的细胞与分子机制仍不甚明确。本研究将12只雄性斯普拉格-道利（Sprague-Dawley）大鼠随机分为常氧对照（Normoxic Control, NC）组与CIH组（每组n=6），CIH暴露时长为12周。采用苏木精-伊红（Hematoxylin and Eosin, HE）染色及改良Jablonski评分评估肾损伤情况，并开展单细胞核RNA测序（Single-nucleus RNA sequencing, snRNA-seq）。数据分析包括细胞聚类、差异基因表达分析，以及通过基因本体论（Gene Ontology, GO）和京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）通路进行功能富集分析。组织病理学分析显示，与NC组相比，CIH组大鼠出现肾损伤，表现为肾小管上皮细胞水肿、坏死。质控后共保留42581个细胞（NC组19655个，CIH组22926个），并鉴定出13种不同的肾细胞群。CIH暴露使足细胞比例升高，而系膜细胞比例较NC组降低。CIH暴露改变了转录组谱，多种细胞类型中均观察到差异表达基因（Differentially Expressed Genes, DEGs）。功能富集分析表明，CIH诱导的差异表达基因在近端小管及亨利袢（loop of Henle）上皮细胞中与代谢通路和信号通路受抑制相关；在远端曲小管上皮细胞中与凋亡通路及钠重吸收通路激活相关；在单核吞噬细胞中则与炎症及吞噬信号通路增强相关。本研究构建了大鼠肾脏中CIH诱导的转录变化高分辨率图谱。本研究结果揭示了细胞类型特异性的应答及潜在参与OSA相关肾损伤的通路，为OSA患者肾损伤的发病机制及潜在防治靶点提供了全新见解。