Abstract
Hypercholesterolemia is characterized by elevated low-density lipoprotein (LDL)-cholesterol levels and an increased risk of cardiovascular disease. The adipokine chemerin is an additional risk factor. Here we investigated whether cholesterol-lowering with statins or proprotein convertase subtilisin-kexin type 9 inhibitors (PCSK9i) affects chemerin. Both statins and PCKS9i lowered plasma LDL-cholesterol, triglycerides and total cholesterol in hypercholesterolemic patients, and increased high-density lipoprotein (HDL)-cholesterol. Yet, only statins additionally reduced chemerin and high-sensitivity C-reactive protein (hsCRP). Applying PCSK9i on top of statins did not further reduce chemerin. Around 20% of chemerin occurred in the HDL2/HDL3 fractions, while >75% was free. Statins lowered both HDL-bound and free chemerin. Pull-down assays revealed that chemerin binds to the HDL-component Apolipoprotein A-I (ApoA-I). The statins, but not PCSK9i, diminished chemerin secretion from HepG2 cells by upregulating LDL receptor mRNA. Furthermore, chemerin inhibited HDL-mediated cholesterol efflux via its chemerin chemokine-like receptor 1 in differentiated macrophages. In conclusion, statins, but not PCSK9i, lower circulating chemerin by directly affecting its release from hepatocytes. Chemerin binds to ApoA-I and inhibits HDL-mediated cholesterol efflux. Statins prevent this by lowering HDL-bound chemerin. Combined with their anti-inflammatory effect evidenced by hsCRP suppression, this represents a novel cardiovascular protective function of statins that distinguishes them from PCSK9i.