Processing of Laminin a Chains Generates Peptides Involved in Wound Healing and Host Defense

Laminins play a fundamental role in basement membrane architecture and function in human skin. The C-terminal laminin G domain-like (LG) modules of laminin a chains are modified by proteolysis to generate LG1-3 and secreted LG4-5 tandem modules. In this study, we provide evidence that skin-derived cells process and secrete biologically active peptides from the LG4-5 module of the laminin a3, a4 and a5 chain in vitro and in vivo. We show enhanced expression and processing of the LG4-5 module of laminin a3 in keratinocytes after infection and in chronic wounds in which the level of expression and further processing of the LG4-5 module correlated with the speed of wound healing. Furthermore, bacterial or host-derived proteases promote processing of laminin a3 LG4-5. On a functional level, we show that LG4-5-derived peptides play a role in wound healing. Moreover, we demonstrate that LG4-derived peptides from the a3, a4 and a5 chains have broad antimicrobial activity and possess strong chemotactic activity to mononuclear cells. Thus, the data strongly suggest a novel multifunctional role for laminin LG4-5-derived peptides in human skin and its involvement in physiological processes and pathological conditions such as inflammation, chronic wounds and skin infection. (C) 2014 S. Karger AG, Basel