Hsa_circ_0007478 aggravates NLRP3 inflammasome activation and lipid metabolism imbalance in ox-LDL-stimulated macrophage via miR-765/EFNA3 axis

Coronary heart disease can be effectively prevented by alleviating atherosclerotic plaque progression. Ox-LDL-induced inflammatory response in macrophages is a critical factor in the pathophysiology of atherosclerosis. It is well known that circular RNAs (circRNAs) are associated with the progression of several human diseases, such as coronary artery diseases, by sponging microRNAs (miRNAs), but the function and hidden mechanisms of circRNAs in macrophage inflammation and lipid metabolism remain unclear. In our study, we established an ox-LDL-stimulated macrophage model and used microarray to detect circRNA expression in macrophages. The results revealed distinct profiles of circRNA expression across the ox-LDL-stimulated macrophage group and the control group. Among them, hsa_circ_0007478 was upregulated in ox-LDL-stimulated macrophages, accompanied by reduced miR-765 and increased EFNA3 expression. Activation of NLRP3 inflammasome and IL-1β in macrophages was decreased following silencing of hsa_circ_0007478 or transfection of miR-765 mimics. In addition, we demonstrated that as a direct target gene of miR-765, the expression of EFNA3 regulated NLRP3 inflammasome and IL-1β levels in macrophages. Besides, hsa_circ_0007478 promoted EFNA3 expression by acting as a miR-765 sponge. We further showed that hsa_circ_0007478/miR-765/EFNA3 axis could also be involved in the inhibition of the lipid metabolism and foam cells formation in ox-LDL-macrophages. Taken together, these findings suggest that Hsa_circ_0007478 may be a potential molecular target against the inflammatory response and foam cells during atherosclerosis.