RNF213 loss-of-function promotes pathological angiogenesis in moyamoya disease via the Hippo pathway.

Abstract

Moyamoya disease (MMD) is an uncommon cerebrovascular disorder characterized by steno-occlusive changes in the circle of Willis and abnormal vascular network development. Ring finger protein 213 (RNF213) has been identified as an important susceptibility gene for Asian patients, but researchers have not completely elucidated whether RNF213 mutations affect the pathogenesis of MMD. Using donor superficial temporal artery (STA) samples, whole-genome sequencing was performed to identify RNF213 mutation types in MMD patients, and histopathology was performed to compare morphological differences between patients with MMD and intracranial aneurysm (IA). The vascular phenotype of RNF213-deficient mice and zebrafish was explored in vivo, and RNF213 knockdown in human brain microvascular endothelial cells (HBMECs) was employed to analyse cell proliferation, migration, and tube formation abilities in vitro. After bioinformatics analysis of both cell and bulk RNA-seq data, potential signalling pathways were measured in RNF213-knockdown or RNF213-knockout endothelial cells (ECs). We found that MMD patients carried pathogenic mutations of RNF213 that were positively associated with MMD histopathology. RNF213 deletion exacerbated pathological angiogenesis in the cortex and retina. Reduced RNF213 expression led to increased EC proliferation, migration, and tube formation. Endothelial knockdown of RNF213 activated the Hippo pathway effector Yes-associated protein (YAP)/tafazzin (TAZ) and promoted the overexpression of the downstream effector VEGFR2. Additionally, inhibition of YAP/TAZ resulted in altered cellular VEGFR2 distribution due to defects in trafficking from the Golgi apparatus to the plasma membrane and reversed RNF213 knockdown-induced angiogenesis. All these key molecules were validated in ECs isolated from RNF213-deficient animals. Our findings may suggest that loss-of-function of RNF213 mediates the pathogenesis of MMD via the Hippo pathway.