P4HA2 knockdown prevents the progression of intracranial aneurysm by inducing prolyl hydroxylation of YAP1.

Abstract

Prolyl 4-hydroxylase subunit alpha 2 (P4HA2), a key enzyme modulating the post-transcription of proteins, was reported to be a causative gene in IA. Nevertheless, the exact function and mechanism of P4HA2 in the formation and rupture of IA is elusive. The current study first explored the expression of P4HA2 and its association with the clinicopathological demonstrations in patients with IA. In addition, an in vitro model of IA was established using H₂O₂ to stimulate vascular smooth muscle cells (VSMCs). The behaviors of treated VSMCs were evaluated using CCK-8, Wound healing, and Transwell assays. The expression of genes was detected by RT-qPCR and Western blot. Interaction between genes was confirmed using Luciferase Reporter assay and Co-immunoprecipitation (Co-IP) assay. Our results revealed that P4HA2 expression was upregulated in IA, especially ruptured IA; high P4HA2 expression correlates with unfavorable clinicopathological parameters. Through the in vitro experiments, it was discovered that P4HA2 knockdown rescued VSMCs from H₂O₂-induced viability impairment, enhancement in migration and apoptosis, switch from contractile phenotype, and augmentation of oxidative stress and inflammation. Mechanistically, P4HA2 was found to trigger the prolyl hydroxylation of YAP1 to negatively regulate the transcriptional activity of YAP1 in H₂O₂-challenged VSMCs. The effect of P4HA2 on H₂O₂-challenged VSMCs could be annulled by the mutation of YAP1 hydroxylation sites. In summary, P4HA2 served as a contributing factor during IA progression through its suppression on YAP1 activity by prolyl hydroxylation.