The sphingolipid ceramide 1-phosphate (C1P) directly binds to and activates group IVA cytosolic phospholipase A 2 (cPLA 2α) to stimulate the production of eicosanoids. Because eicosanoids are important in wound healing, we examined the repair of skin wounds in knockout (KO) mice lacking cPLA 2α and in knock-in (KI) mice in which endogenous cPLA 2α was replaced with a mutant form having an ablated C1P interaction site. Wound closure rate was not affected in the KO or KI mice, but wound maturation was enhanced in the KI mice compared to that in wild-type controls. Wounds in KI mice displayed increased infiltration of dermal fibroblasts into the wound environment, increased wound tensile strength, and a higher ratio of type I:type III collagen. In vitro, primary dermal fibroblasts (pDFs) from KI mice showed substantially increased collagen deposition and migration velocity compared to pDFs from wild-type and KO mice. KI mice also showed an altered eicosanoid profile of reduced proinflammatory prostaglandins (PGE 2 and TXB 2) and an increased abundance of certain hydroxyeicosatetraenoic acid (HETE) species. Specifically, an increase in 5-HETE enhanced dermal fibroblast migration and collagen deposition. This gain-of-function role for the mutant cPLA 2α was also linked to the relocalization of cPLA 2α and 5-HETE biosynthetic enzymes to the cytoplasm and cytoplasmic vesicles. These findings demonstrate the regulation of key wound-healing mechanisms in vivo by a defined protein-lipid interaction and provide insights into the roles that cPLA 2α and eicosanoids play in orchestrating wound repair.
Bibliographical noteFunding Information:
We would like to thank J. Ryan and laboratory group in the Biology Department at VCU for use of laboratory space to finish experiments integral to the completion of this manuscript This work was supported by research grants from the Veteran?s Administration [VA Merit Review, I BX001792 (C.E.C.) and a Research Career Scientist Award, 13F-RCS-002 (C.E.C.)] and from the NIH via HL125353 (C.E.C., R.E.B., and E.H.H.), HD087198 and RR031535 (C.E.C.), R01138495 (J.J.R.), and F32Al108088 (L.A.H.). The contents of this manuscript do not represent the views of the Department of Veterans Affairs or the U.S. government. Microscopy was performed at the VCU Microscopy Facility, supported, in part, by funding from NIH-NCI Cancer Center Support Grant P30 CA016059.
Copyright © 2019 The Authors,
PubMed: MeSH publication types
- Research Support, U.S. Gov't, Non-P.H.S.
- Journal Article
- Research Support, N.I.H., Extramural