Epigenetic in Obstructive Sleep Apnea: miR-145-5p targets DNMT3A and regulates DNA methylation homeostasis in upper airway muscle

Abstract

Abstract Background Epigenetic modifications, especially DNA methylation and post-transcriptional miRNA-mediated regulation, are closely related to the occurrence and development of obstructive sleep apnea (OSA). Our previous study found that reduced expression of miR-145-5p may be a serological early warning marker for OSA diagnosis alone, but the underlying mechanism is unknown. Objectives To explore the underlying mechanism of miR-145-5p affects DNA methylation homeostasis in upper airway muscle. Methods Primary genitourinary muscle cells were extracted from Sprague-Dawley rats and cultured under intermittent hypoxic conditions for 12h to mimic the OSA pattern. The targeted regulatory relationship between miR-145-5p and DNMT3A was confirmed by bioinformatics predictions and dual luciferase reports. At last, we performed Whole Genome Bisulfite Sequencing (WGBS) in miR-145-5p overexpression genioglossus cells and the negative control cells (n = 3, each group). Results We found that intermittent hypoxia can increase the expression of DNMT3A in the genioglossus cells, and miR-145-5p regulates the expression and transcriptional activity of DNMT3A. WGBS results showed that 5738 CpG gDMR genes and 1006 CpG gDMR promoter-associated genes were differentially methylated. Gene Ontology enrichment analysis of CpG gDMR genes revealed that they were mainly involved in the regulation of plasma membrane part, cell projection, and plasma membrane-bounded cell projection. KEGG pathway enrichment analysis revealed that they were mainly involved in the MAPK signaling pathway, cAMP pathway, and PI3K/AKT pathway. Conclusions Our findings contribute to growing evidence that exposure to chronic intermittent hypoxia alters DNA methylation patterns in patients with OSA, and present the first global DNA methylation description of the impact of chronic intermittent hypoxia exposure on upper airway muscle in vitro. In particular, our results suggest that miR-145-5p regulates DNA methylation homeostasis in upper airway muscle by targeting DNMT3A, which provides new knowledge to understand the potential mechanism of OSA occurrence and development.