MCM8 mediated mitophagy protects vascular health in response to nitric oxide signaling in a mouse model of Kawasaki disease

Mitophagy is a major quality control pathway that removes unwanted or dysfunctional mitochondria, and plays an essential role in vascular health. Here we show that MCM8 expression is significantly decreased in children with Kawasaki disease (KD) who developed coronary artery aneurysms. Mechanistically, we discover that nitric oxide (NO) signaling promotes TRIM21 mediated MCM8 ubiquitination, which disrupts its interaction with MCM9 and promotes its cytosolic export. In the cytosol, MCM8 relocates to the mitochondria pore forming proteins and promotes their ubiquitination by TRIM21. In addition, MCM8 directly recruits LC3 via its LIR motif and initiates mitophagy. This suppresses mitochondrial DNA-mediated activation of type I interferon via cGAS and STING. Mice that are deficient in Mcm8, Trim21, Nos2, or reconstituted with the East-Asian specific MCM8-P276 variant develop more severe coronary artery vasculopathy in the Lactobacillus casei extract-induced KD model. Collectively, the data suggest that MCM8 protects vascular health in the KD setting. Overall design: To investigate the role of MCM8 in protecting vascular health, we constructed wild type (Wt) and Mcm8-knock out mouse model of Kawasaki disease. Then we extracted total RNA from heart tissues and compared the transcriptomic differences of Wt and MCM8-/- mice under PBS or LCWE treatment.