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Exploring the Role of EBP50 in Vascular Inflammation

Leslie, Kristen (2013) Exploring the Role of EBP50 in Vascular Inflammation. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Inflammation is a necessary biological response to injury and infections, but chronic activation can lead to a host of diseases. This beneficial-turned-destructive process plays a fundamental role in the development of cardiovascular diseases, and the vascular response requires communication between multiple cell types such as vascular smooth muscle cells (VSMC) and macrophages. A PDZ-domain scaffolding protein, Ezrin-Radixin-Moesin-Binding Phosphoprotein 50 (EBP50, also known as NHERF1), is expressed at low levels in normal vessels but is upregulated following arterial wire injury and promotes neointima formation. However, the mechanisms underlying these actions are not fully understood. I hypothesized that EBP50 functions as a central mediator of macrophage activation and the response of VSMC to inflammation. EBP50 expression increased in an NF-κB-dependent manner upon LPS or TNFα treatment macrophages and VSMC. Conversely, NF-κB activation was impaired in EBP50 knockout (KO) VSMC and macrophages. Mechanistically, inflammatory stimuli induced the formation of an EBP50-PKCζ complex that promoted PKCζ membrane translocation and subsequent NF-κB signaling. Macrophage cytokine production (IL-1β, TNFα) and vascular adhesion molecule expression (ICAM-1, VCAM-1) after acute LPS or TNFα treatment were reduced in KO cells and mice compared to WT. Bridging the multicellular effects of EBP50, macrophage recruitment to lesions in the femoral artery one week after wire injury was significantly reduced in KO mice.
The effect of myeloid cell-specific EBP50 on atherosclerosis was determined in Ldlr-/- mice, a well-established model of diet-induced atherosclerosis. Mice were lethally irradiated and transplanted with bone marrow from WT or KO mice and kept on a high-cholesterol diet for 12 weeks. A complete blood count and genotyping of hematopoietic cells established the successful ablation of original bone marrow and the full reconstitution of the donor marrow. No differences in weight, blood glucose, or cholesterol levels were observed between the two groups. Oil Red O staining of sections throughout the aorta revealed a 25% reduction in lesion area in KO bone marrow recipients compared to WT.
Collectively, these new findings indicate that EBP50 potentiates macrophage activation and the response of VSMC to inflammation. Thus, EBP50 is a key regulator of vascular remodeling during both acute and chronic inflammatory states.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Leslie, Kristenklb120@pitt.eduKLB120
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorBisello, Alessandroalb138@pitt.eduALB138
Committee ChairPagano, Patrickpagano@pitt.eduPAGANO
Committee MemberRomero, Guillermoggr@pitt.eduGGR
Committee MemberShiva, Srutisss43@pitt.eduSSS43
Committee MemberO'Doherty, Robertodohertyr@dom.pitt.eduRMO1
Date: 15 August 2013
Date Type: Publication
Defense Date: 6 August 2013
Approval Date: 15 August 2013
Submission Date: 14 August 2013
Access Restriction: 1 year -- Restrict access to University of Pittsburgh for a period of 1 year.
Number of Pages: 146
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Molecular Pharmacology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Vascular Biology, Scaffold Proteins, Inflammation, Macrophages, NF-kappaB, EBP50
Date Deposited: 15 Aug 2013 18:56
Last Modified: 15 Nov 2016 14:14


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