Date of Award

2014

Document Type

Open Access Thesis

Department

Biomedical Science

First Advisor

Kevin Carnevale

Abstract

Abstract 1: Platelet derived growth factor BB (PDGF BB) has an important influence on smooth muscle cell proliferation in restenosis and atherosclerosis. Our understanding of different signal transduction pathways involved in the response of smooth muscle cells to PDGF BB is potentially significant for understanding and manipulating these processes. Prior studies have demonstrated a crucial activation of cytosolic phospholipase A2 (cPLA2) in smooth muscle cells to PDGF BB with the production of arachidonic acid and prostaglandin E2. In these studies we investigated the role for another PLA2, calcium-independent PLA2 (iPLA2) in comparison to cPLA2 on smooth muscle cell migration and proliferation. Pharmacological inhibitors of cPLA2 were found to substantially inhibit proliferation, but not migration. AACOCF3 (cPLA2 and iPLA2 inhibitor) and 1,2,4-trisubstituted pyrrolidine derivative (cPLA2 inhibitor) both inhibited smooth muscle proliferation where Bromoenol lactone (iPLA2 inhibitor) had no effect. None of these inhibitors prevented smooth muscle chemotaxis to PDGF BB in a modified Boyden chamber. In reconstitution experiments, arachidonic acid fully restored smooth muscle cell proliferation after treatment with 1,2,4-trisubstituted pyrrolidine derivative. These data demonstrate the distinct role of cPLA2 on smooth muscle cell proliferation, which is a critical step in the pathogenesis of restenosis and atherosclerosis.

Abstract 2: There are major histological differences between normal murine aorta and femoral artery. There are also major differences in the effects of atherosclerosis on these two arteries with aneurysm formation affecting the aorta and long complex atherosclerotic lesions affecting the femoral artery, which result in lumen narrowing. Our overall understanding of the different proteins expressed in these two arteries is not well understood. In these studies we investigated the difference in protein expression in normal murine abdominal aorta compared to femoral artery. We found that tropomyosin alpha 1 and beta from murine femoral artery migrates to different locations on 2D gel electrophoresis. Further investigation using western blot analysis shows that these two proteins migrate to the same location. We hypothesize that another protein(s) is bound to tropomyosin in femoral artery and not in abdominal aorta to form a complex that causes the protein to migrate differently on 2D analysis.

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