Circ_FOXO3 regulates KLF6 through sponge adsorption of miR-122-5p to repress H2O2-induced HBVSMC proliferation, thus promoting IA development in vitro model.

Abstract

The phenotypic transformation of human brain vascular smooth muscle cells (HBVSMC) is widely involved in the appearance and progression of intracranial aneurysms (IA). Aneurysm (IA) Circular RNA circ_FOXO3 functions pivotally in vascular diseases and tumors, but its regulatory role as well as its molecular mechanism in IA is still uncertain. This research was to explore how circ_FOXO3 works and its mechanism in vitro model of HBVSMC IA induced by H2O2. Thirty-eight patients with IA and their normal tissues were clinically collected. Examination of endothelin-1, vascular hematoma factor, circ_FOXO3, microRNA (miR)-122-5p and KLF6 and the correlation of circ_FOXO3 with clinical case information were ensured. Establishment of an in vitro IA model was through HBVSMC induced by H2O2 and transfection with circ_FOXO3, miR-122-5p and KLF6 related plasmids was to figure out their roles in cell growth. The relationship among circ_FOXO3, miR-122-5p with KLF6 was detected. Up-regulated circ_FOXO3 and KLF6 and reduced miR-122-5p were in IA tissues; Circ_FOXO3 was associated with smoking history, Hunt-Hess grading and endothelial injury degree. Repressive circ_FOXO3 or KLF6 and strengthening miR-122-5p facilitated H2O2-induced proliferation and repressed HBVSMC apoptosis, while elevation of circ_FOXO3 or depressive miR-122-5p was opposite. circ_FOXO3 bound to miR-122-5p, whose target was KLF6, which participated in controlling IA by mediating the circ_FOXO3/miR-122-5p axis. In summary, the findings suggest that circ_FOXO3 suppresses H2O2-induced proliferation of HBVSMC but promotes apoptosis via modulation of miR-122-5p/KLF6 axis. Targeted therapy of circ_FOXO3/miR-122-5p/KLF6 axis is supposed to be a promising treatment approach for IA patients.