The dual role of cathelicidins in systemic inflammation

Highlights • Antimicrobial peptides are key components of the innate immune system. • Cathelicidins are a class of antimicrobial peptide found in humans, mice, and rats, among others. • The role of cathelicidins is somewhat confounding, as they exhibit both pro-and anti-inflammatory activity. A major obstacle in the study of cathelicidins is the inability of exogenous LL-37 or CRAMP to mimic the activity of their endogenous counterparts. • Nevertheless, studies have shown that LL-37 is recognized by multiple receptors, and may stabilize or modulate Toll-like receptor signaling. • This letter reviews what is currently known about the dual activity of cathelicidins in an attempt to understand their complex roles in systemic diseases.