BACKGROUND: Long noncoding RNAs (lncRNAs) were identified as potential regulatory factor in vascular disease. However, the role of XR007793 in the regulation of neointima formation after vascular injury remains largely unknown.

MATERIAL AND METHODS: LncRNA expression levels were detected using real-time polymerase chain reaction (RT-PCR). In vivo and in vitro assay were performed in Sprague-Dawley rats and VSMCs. Cell Counting Kit-8 (CCK-8) assay, Transwell assay, and scratch wound healing assay were performed to detect cell proliferation and migration. Western blotting was used to detect protein expression.

RESULTS: The results of qRT-PCR indicated that XR007793 expression was significantly increased in the injured carotid artery of Sprague-Dawley rats and platelet-derived growth factor-BB induced rat aortic smooth muscle cells. Knockdown of XR007793 repressed the proliferation and migration of VSMC in vitro. The expression level of miR-23b was reduced in mouse carotid injured tissues and cell line. Bioinformatics analysis and luciferase reporter assay revealed that XR007793 directly bonds to miR-23b. Pearson correlation analysis showed that XR007793a and miR-23b were negatively correlated in carotid samples. Furthermore, bioinformatics analysis and luciferase assay indicated that miR-23b targeted the Forkhead box O 4 (FOXO4) 3’-UTR to inhibit FOXO4 expression. After transfecting miR-23b inhibitor, the expression both of XR007793 and FOXO4 was increased. The effects on expression were reversed after transfected with miR-23b mimics. Rescue experiments results indicated that miR-23b inhibitor reduced the expression of VSMC marker and promoted proliferation and migration of VSMC.

CONCLUSIONS: This study shows that XR007793 aggravates the loss of function of VSMCs by negatively regulating miR-23b. It does so by targeting FOXO4, which could serve as a novel therapeutic target in post-angioplasty restenosis.

Keywords: Muscle, Smooth, Vascular