The atypical protein kinase RIOK3 contributes to the phenotypic modulation of vascular smooth muscle cells in intracranial aneurysms

BackgroundPrevious studies manifested that abnormal proliferation, migration, apoptosis, and phenotypic conversion of vascular smooth muscle cells (VSMCs) are the main pathogenic basis of intracranial aneurysms (IAs).ObjectiveThe aim of this study was to explore a key gene associated with IA growth and rupture using bioinformatics analysis and validate it by exogenous overexpression into human brain VSMCs (HBVSMCs). Four IA-associated microarray datasets, GSE54083, GSE15629, GSE66238, and GSE13353, were obtained from Gene Expression Omnibus (GEO) and analyzed using GEO2R for differentially expressed genes (DEGs). HBVSMCs were infected with lentivirus containing RIO kinase 3 (RIOK3) to overexpress exogenous RIOK3, and then, CCK-8, EdU, cell scratch, Transwell, Western blotting, and ELISA were introduced to measure proliferation, migration, phenotypic conversion-related proteins, and proinflammatory cytokines in HBVSMCs. To simulate the abnormal hemodynamic environment in the late stages of IA formation, RIOK3-overexpressing HBVSMCs were cultured under wall shear stress (WSS)-loaded conditions and then subjected to apoptosis assessment.ResultsRIOK3 was defined as a key gene in the DEGs of IAs by bioinformatics analysis. RIOK3 overexpression could contribute to the abnormal proliferation, migration, secretion of proinflammatory factors, and the conversion of contractile phenotype to synthetic phenotype of HBVSMCs. Additionally, RIOK3 overexpression encouraged HBVSMC apoptosis after loading WSS in vitro to mimic advanced-IAs.ConclusionRIOK3 in pre-IAs (without WSS loading) facilitates phenotypic conversion, abnormal proliferation, invasion, and inflammatory cytokine secretion of HBVSMCs; whereas in the advanced-IAs, RIOK3 accelerated the abnormal apoptosis of HBVSMCs in the setting of loaded-WSS.