Abstract
Cathelicidins are a family of antimicrobial peptides that are found in several mammalian species.They consist of a highly conserved N-terminal prosequences (a cathelin-like domain) and variable C-terminal sequences that is retained within the mature antibacterial peptide. LL-37 is the sole mature cathelicidin peptide found in humans. It is composed of 37 amino acids and exhibits an α-helical structure. Although LL-37 exerts a broad spectrum of antimicrobial activities against bacteria, fungi, and certain viruses, there is currently much focus on the various effects of the peptide on host cells. Growing evidence suggests that LL-37 binds to host cell surface receptors and induces immunomodulatory responses in neutrophils, monocytes/macrophages, dendritic cells, T cells, mast cells, and epithelial cells. LL-37 also acts on endothelial cells and induces cell proliferation, angiogenesis, upregulated adhesion molecule expression, and increased cell stiffness. Moreover, LL-37 is incorporated into host cells and modulates host cell responses by itself or by forming a complex with host/pathogen-derived components. In this review, we describe the effects of LL-37 on endothelial cells and present the findings of our recent study, which revealed that LL-37 contributes to lipopolysaccharide (LPS) clearance by liver sinusoidal endothelial cells by forming complexes with Gram-negative LPS. Finally, we discuss the involvement of LL-37 in atherosclerosis and regeneration.
© 2016 The Juntendo Medical Society. This is an open access article distributed under the terms of Creative Commons Attribution License (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original source is properly credited.
