Aims: MicroRNAs have been demonstrated to be involved in the development of atherosclerosis. The present study aimed to evaluate the effect of miR-99a-5p and its target gene Homeobox A1 (HOXA1) in atherosclerosis.
Main methods: The biological functions of miR-99a-5p on human aortic smooth muscle cells (ASMCs) were assessed by MTT, wound healing and transwell assays. The target genes of microRNAs were predicted by TargetScan and miRDB. The binding of miR-99a-5p and HOXA1 was confirmed by luciferase reporter assay. In the in vivo study, high-fat diet-induced atherosclerosis model was established in Apolipoprotein E knockout mice. Hematoxylin-eosin (H&E), oil Red O and Masson trichrome staining were performed for determination of atherosclerotic lesion. The levels of miR-99a-5p and HOXA1 mRNA were detected by real-time PCR. HOXA1 and migration-associated protein levels were detected by western blot or immunohistochemistry analysis.
Key findings: MiR-99a-5p inhibited HOXA1 expression by targeting 3'UTR of HOXA1 mRNA. Enforced HOXA1 significantly promoted the proliferation, migration, and invasion of ASMCs. Furthermore, miR-99a-5p overexpression inhibited the proliferation, migration, and invasion of ASMCs stimulated by HOXA1, whereas miR-99a-5p inhibition reversed the effects of HOXA1 knockdown on these behaviours of ASMCs. In vivo, the specific overexpression of miR-99a-5p significantly abated atherosclerotic lesions formatted, accompanied with a significant down-regulation of HOXA1 mRNA and protein expression levels.
Significance: We demonstrate for first time that miR-99a-5p may serve as a potential inhibitor of the atherosclerosis, and miR-99a-5p plays its role partially through targeting HOXA1.
Keywords: Apolipoprotein E knockout mice; Atherosclerosis; Homeobox A1; Human aortic smooth muscle cells; MicroRNA-99a-5p.
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