ECH 1 attenuates atherosclerosis by reducing macrophage infiltration and improving plaque stability through CD36 degradation.

Enoyl coenzyme A hydratase 1 (ECH1) is a secreted protein implicated in numerous metabolic disorders, yet its role in the pathogenesis of atherosclerosis remains unclear. In this study, we found higher serum ECH1 levels in coronary artery disease (CAD) patients and apolipoprotein E (ApoE)^-/- mice on a western diet for 12 weeks. In vivo, aorta and aortic sinus histological staining revealed that intraperitoneal injection of recombinant ECH1 reduced aortic lesions, inflammation, and macrophage infiltration in ApoE^-/- mice. In vitro, incubating peritoneal macrophages with recombinant ECH1 protein reduced oxidized low-density lipoprotein uptake and increased macrophage migration. Mechanically, we observed that recombinant ECH1 incubation led to a reduction in the protein levels of scavenger receptor cluster of differentiation 36 (CD36) in primary macrophages through the promotion of CD36 protein degradation. Additionally, we found that chloroquine (CQ), a lysosomal inhibitor, mitigated this pro-degradation effect. Taken together, our findings provide unique evidence that ECH1 can attenuate the severity of atherosclerotic plaques, especially improving the stability of plaques, by decreasing macrophage infiltration. ECH1 demonstrates its protective effect by enhancing the lysosome-dependent degradation of CD36, suggesting its potential as a viable target for the prevention and treatment of atherosclerosis.