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THE SCAFFOLDING PROTEIN EBP50 REGULATES MITOCHONDRIAL DYNAMICS AND REDOX BALANCE IN VASCULAR SMOOTH MUSCLE CELLS

Procaccia, Vera (2018) THE SCAFFOLDING PROTEIN EBP50 REGULATES MITOCHONDRIAL DYNAMICS AND REDOX BALANCE IN VASCULAR SMOOTH MUSCLE CELLS. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Abstract

Cardiovascular disease is the leading cause of death worldwide. Vascular smooth muscle cells (VSMC) have a critical role in vascular pathologies such as restenosis, atherosclerosis and pulmonary arterial hypertension. Following injury or inflammation VSMC switch from a quiescent state to proliferative, migratory and secretory phenotype. These changes contribute to the progression of vascular disease and are regulated by various cellular factors including mitochondria.
Mitochondria are a central source of reactive oxygen species (ROS) in the cell and are undergoing constant morphological changes (fusion and fission) that allow a proper response to changes in the cellular environment. A family of large GTPases that include mitofusin-2 (Mfn2) and dynamin related protein 1 (Drp1) regulates mitochondrial shape. The activity and expression of these shaping proteins are regulated by multiple mechanisms including post translational modifications, degradation and transcription. The scaffolding protein Ezrin Radixin Moesin binding phosphoprotein-50 (EBP50) plays an important role in vascular remodeling. EBP50 regulates numerous cellular processes by controlling localization and function of proteins it interacts with. Among EBP50 partners are the S-phase kinase associated protein 2 (Skp2) that ubiquitinates and targets for degradation Forkhead box protein O1 (FoxO1) and Protein Kinase Cζ (PKCζ) that is activated by Tumor Necrosis Factor α (TNFα) in VSMC.
In my thesis work I found that EBP50 regulates mitochondrial morphology and fragmentation by affecting Mfn2 levels, through regulation of FoxO1 stability, and Drp1 phosphorylation through activation of PKCζ. In addition, I demonstrated that EBP50 regulates the expression of two important enzymes, MnSOD and catalase and affects mitochondrial superoxide levels. Cellular bioenergetics analysis revealed that EBP50-/- VSMC have lower glycolytic metabolism consistent with the lower proliferative response of EBP50 depleted VSMC to TNFα. In addition, increased levels of MnSOD in EBP50-/- VSMC reduced cell migration and conversely, MnSOD knock down, increased VSMC migration.
Taken together, my data shows that the effects of EBP50 on mitochondrial morphology and redox balance have significant impacts on VSMC metabolism, proliferation and migration and could contribute to the progression of vascular diseases. Therefore, EBP50 should be considered as a central regulator of vascular remodeling and a potential therapeutic target for vascular disorders.


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Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Procaccia, Veravep13@pitt.eduvep13
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairKensler, Thomastkensler@pitt.edu
Thesis AdvisorBisello, Alessandroalb138@pitt.edu
Committee MemberShiva, Srutisss43@pitt.edu
Committee MemberStolz, Donnadonna.stolz@pitt.edu
Committee MemberSchopfer, Franciscofjschopfer@katz.pitt.edu
Date: 19 April 2018
Date Type: Publication
Defense Date: 6 April 2018
Approval Date: 19 April 2018
Submission Date: 18 April 2018
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Number of Pages: 124
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: EBP50, NHERF-1, TNF, PKC, Mitochondria, Mitochondrial dynamics, Drp1, mitofusin2, proliferation, vascular smooth muscle cells, MnSOD, redox balance
Date Deposited: 19 Apr 2018 13:40
Last Modified: 19 Apr 2018 13:40
URI: http://d-scholarship.pitt.edu/id/eprint/34333

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