Peptide-agonist of protease-activated receptor (PAR1) stimulates keratinocyte proliferation and epithelial layer wound healing similarly to activated protein C

Abstract

Activated protein C (APC) is a serine protease involved in hemostasis; APC also exhibits antiinflammatory and anti-apoptotic properties, which are independent of its anticoagulant activity; these properties determine a possibility of the protective effects of APC in various diseases, including sepsis and healing of chronic wounds. We have hypothesized that the cytoprotective effect of APC on the cells, involved in wound healing, may be mimicked by peptide analogues of PAR1 “tethered ligand” activating PAR1. In order to test this hypothesis experimentally, we have synthesized a peptide (AP9)—analogue of the PAR1 tethered ligand, released by APC, and demonstrated for the first time that the AP9 peptide (0.1–10 μM), like to APC (0.01–100 nM), stimulates the proliferative activity of human primary keratinocytes. Using a model of the epithelial layer wounds we found that peptide AP9, as well as protease APC, accelerates wound healing. Using specific antibodies we have investigated the receptor mechanism of the AP9 effect in wound healing compared with the APC action. The proliferative activity of agonists requires both PAR1 receptor and endothelial protein C receptor (EPCR). Imitation of APC effect on keratinocytes by peptide AP9, PAR1 ligand, found in this study suggests the possibility of the use of peptide AP9 for stimulation of tissue repair.