Kai Yin1, Xianzhi Liu2. 1. Department of Neurosurgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China. 2. Department of Neurosurgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China. Electronic address: yfyliuxianzhi@163.com.
Abstract
AIMS: Circ_0020397 has been found to be down-regulated in intracranial aneurysm (IA), and deregulation of circ_0020397 involved in the regulation of vascular smooth muscle cells (VSMCs) proliferation. However, the mechanism by which circ_0020397 implicates in VSMC dysfunction in IA remains vague. MATERIALS AND METHODS: The expression of circ_0020397, miR-502-5p and Gremlin 1 (GREM1) was detected using quantitative real-time polymerase chain reaction. Cell viability was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Protein levels of proliferating cell nuclear antigen (PCNA) and GREM1 were measured using western blot. The interaction between miR-502-5p and circ_0020397 or GREM1 was confirmed by dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation assay. KEY FINDINGS: Circ_0020397 or GREM1 expression was decreased in VSMCs isolated from IA patients, and overexpression of circ_0020397 or GREM1 promoted VSMC viability and elevated PCNA expression level, while inhibition of them showed opposite effects. MiR-502-5p was confirmed to directly bind to circ_0020397 or GREM1, and miR-502-5p reversed the effects of circ_0020397 on VSMC viability and PCNA level. Besides, miR-502-5p overexpression suppressed VSMC viability and reduced PCNA level, while these effects were attenuated by GREM1 up-regulation. Importantly, circ_0020397 could regulate GREM1 expression via miR-502-5p in VSMCs. SIGNIFICANCE: Circ_0020397 played an important role in phenotypic modulation in IA by promoting VSMC viability via miR-502-5p/GREM1 axis, suggesting a novel insight into IA pathogenesis and new targets for IA molecular therapy.
AIMS: Circ_0020397 has been found to be down-regulated in intracranial aneurysm (IA), and deregulation of circ_0020397 involved in the regulation of vascular smooth muscle cells (VSMCs) proliferation. However, the mechanism by which circ_0020397 implicates in VSMC dysfunction in IA remains vague. MATERIALS AND METHODS: The expression of circ_0020397, miR-502-5p and Gremlin 1 (GREM1) was detected using quantitative real-time polymerase chain reaction. Cell viability was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Protein levels of proliferating cell nuclear antigen (PCNA) and GREM1 were measured using western blot. The interaction between miR-502-5p and circ_0020397 or GREM1 was confirmed by dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation assay. KEY FINDINGS: Circ_0020397 or GREM1 expression was decreased in VSMCs isolated from IA patients, and overexpression of circ_0020397 or GREM1 promoted VSMC viability and elevated PCNA expression level, while inhibition of them showed opposite effects. MiR-502-5p was confirmed to directly bind to circ_0020397 or GREM1, and miR-502-5p reversed the effects of circ_0020397 on VSMC viability and PCNA level. Besides, miR-502-5p overexpression suppressed VSMC viability and reduced PCNA level, while these effects were attenuated by GREM1 up-regulation. Importantly, circ_0020397 could regulate GREM1 expression via miR-502-5p in VSMCs. SIGNIFICANCE: Circ_0020397 played an important role in phenotypic modulation in IA by promoting VSMC viability via miR-502-5p/GREM1 axis, suggesting a novel insight into IA pathogenesis and new targets for IA molecular therapy.