Cholesterol binding stabilizes the activated state of THIK-1 and promotes atherosclerosis

Atherosclerosis, a chronic inflammatory disorder, remains a leading cause of global morbidity and mortality. While cholesterol is known to activate the NLRP3-IL-1β pathway and promote plaque formation, the underlying mechanisms remain incompletely understood. Here, we identify the tandem pore domain halothane-inhibited potassium channel 1 (THIK-1) as a mediator of IL-1β release during atherosclerosis progression. Using high-resolution cryo-electron microscopy (cryo-EM), we determine the structure of THIK-1 in its apo form and in complex with the activator arachidonic acid, and the inhibitors halothane and C101248 as well as the structure of the disease-related THIK-1 R92S variant. Structural analyses reveal that cholesterol unexpectedly stabilizes the arachidonic acid-binding pocket within THIK-1. Complementary cellular assays confirm that cholesterol amplifies the arachidonic acid-induced inflammatory response in macrophages, which can be effectively suppressed by the THIK-1 inhibitors halothane and C101248. Moreover, treatment with C101248 markedly reduces atherosclerotic plaque development in Apoe-deficient mice fed a high-cholesterol diet. Collectively, these findings elucidate a cholesterol-dependent mechanism of THIK-1 regulation and highlight THIK-1 as a regulator of atherosclerosis.