DOI
https://doi.org/10.25772/GAXM-PM48
Author ORCID Identifier
0000-0003-3232-6155
Defense Date
2018
Document Type
Dissertation
Degree Name
Doctor of Philosophy
Department
Biochemistry
First Advisor
Charles Chalfant
Abstract
The sphingolipid, ceramide-1-phosphate (C1P), directly binds and activates Group IVA cytosolic phospholipase A2 (cPLA2a) to generate eicosanoids. Due to the role of eicosanoids in wound healing, we choose to use our novel genetic mouse model expressing cPLA2a with an ablated C1P interaction site (KI) to examine the cPLA2a/C1P interaction in wound healing. Wound closure rate was not affected, but wound maturation was dramatically enhanced by loss of the C1P/cPLA2α interaction based on the following findings. Wounds in KI mice displayed: i) increased infiltration of dermal fibroblasts into the wound environment; ii) increased wound tensile strength; and iii) higher Type I/Type III collagen ratios. These findings were recapitulated in vitro as primary dermal fibroblasts (pDFs) from KI mice showed significantly increased collagen deposition and migration velocity compared to WT and KO pDFs. Additionally, the KI showed an altered eicosanoid profile of reduced pro-inflammatory prostaglandins (e.g., PGE2) and increased levels of specific HETE species (e.g., 5-HETE). Elevated 5-HETE levels promoted increased dermal fibroblast migration and collagen deposition. This “gain of function” role for the mutant cPLA2a was also linked to differential cellular localization of cPLA2α and 5-HETE biosynthetic factors. These studies demonstrate regulation of key in vivo biological mechanisms by a defined protein:lipid interaction and provide new insights into cPLA2a function.
Rights
© The Author
Is Part Of
VCU University Archives
Is Part Of
VCU Theses and Dissertations
Date of Submission
11-5-2018