variant and autophagic impairment: A pivotal link to endothelial dysfunction in moyamoya disease.

Moyamoya disease (MMD) is closely associated with the Ring Finger Protein 213 (), a susceptibility gene for MMD. However, its biological function remains unclear. We aimed to elucidate the role of in the damage incurred by human endothelial cells under oxygen-glucose deprivation (OGD). We analyzed autophagy in peripheral blood mononuclear cells (PBMCs) derived from patients carrying either wildtype (WT) or variant (p.R4810K). Subsequently, human umbilical vein endothelial cells (HUVECs) were transfected with WT (HUVEC) or p.R4810K (HUVEC) and exposed to OGD for 2 h. Immunoblotting was used to analyze autophagy marker proteins, and endothelial function was analyzed by tube formation assay. Autophagic vesicles were observed using transmission electron microscopy. Post-OGD exposure, we administered rapamycin and cilostazol as potential autophagy inducers. The variant group during post-OGD exposure (vs. pre-OGD) showed autophagy inhibition, increased protein expression of SQSTM1/p62 (0.0001) and LC3-II (0.0039), and impaired endothelial function (0.0252). HUVEC during post-OGD exposure (versus pre-OGD) showed a remarkable increase in autophagic vesicles. Administration of rapamycin and cilostazol notably restored the function of HUVEC and autophagy. Our findings support the pivotal role of autophagy impaired by the variant in MMD-induced endothelial cell dysfunction.