Involvement of the Antimicrobial Peptide LL-37 in Human Atherosclerosis

Objective— Antimicrobial peptides are effector molecules of the innate immune system. To understand the function of vascular innate immunity in atherosclerosis, we investigated the role of LL-37, a cathelicidin antimicrobial peptide, in the disease process. Methods and Results— Using real-time polymerase chain reaction, we found a 6-fold increase in human cationic antimicrobial protein 18/LL-37 transcript in human atherosclerotic lesions compared with normal arteries. Immunohistochemical analysis of atherosclerotic plaques showed that LL-37 was expressed mainly by macrophages and some endothelial cells. Western blot demonstrated existence of active LL-37 peptide and abundant proprotein in atheroma specimens. To understand the functional implication of LL-37 production in atherosclerosis, the transcription profile was assessed in endothelial cells treated with LL-37. Our data show that LL-37 induces expression of the adhesion molecule intercellular adhesion molecule-1 and the chemokine monocyte chemoattrac...