Reactive oxygen species derived from NADPH oxidases and inflammation have been implicated in most vascular diseases, but also play a role in normal physiology and vascular healing via regulation of smooth muscle cell (SMC) proliferation and matrix secretion. Our laboratory has recently discovered a novel p22phox binding protein, polymerase delta interacting protein-2 (Poldip2), which regulates Nox4, polymerase-? and cell cycle proteins and has important roles in growth, migration and collagen secretion. In this proposal, we test the hypothesis that the multiple roles of Poldip2 in vascular cells are a function of its binding partners, and that these functions can be specifically targeted using small interfering peptides.
In Aim 1, we plan to characterize the physical interaction between Poldip2 and p22phox with the goal of defining peptides that can be used to specifically disrupt this interaction therapeutically. Truncation mutants and pulldown assays will be used to define interacting regions and to design peptides for cell and animal delivery.
Aim 2 is devoted to using these peptides to determine the mechanism by which Poldip2 regulates extracellular collagen levels. We will test the hypothesis that depletion of Poldip2 reduces autophagy, thus enhancing collagen secretion.
In Aim 3, we will determine the specific consequence of smooth muscle Poldip2-mediated matrix regulation on arterial stiffness and aneurysm formation using Poldipflox/flox animals crossed with smooth muscle-specific Cre mice in both chronic and acute settings, as well as hydrogel- or microparticle-mediated delivery of peptide decoys. Together, the experiments described in this proposal will not only extend our understanding of the vascular biology of Poldip2, but will allow us to take the first step towards translating our findings into a therapeutic modality potentially useful for treating vascular disease.

Public Health Relevance

Aortic stiffness (hardening of the arteries) is a risk factor for cardiovascular diseases that are major causes of death in the United States, but can be protective in the setting of aneurysms. The purpose of this proposal is to understand the role of a protein called polymerase-delta interacting protein (Poldip2) in regulating the structure of blood vessels. We will study the structure and function of Poldip2 in cultured cells, investigate how it regulates collagen secretion and the composition of the vessel wall, and then test a novel therapeutic intervention that could protect against deleterious vascular remodeling.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL095070-10
Application #
9692782
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Program Officer
Hasan, Ahmed a K
Project Start
Project End
2020-10-31
Budget Start
2019-05-01
Budget End
2020-04-30
Support Year
10
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Emory University
Department
Type
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
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Yeligar, Samantha M; Kang, Bum-Yong; Bijli, Kaiser M et al. (2018) PPAR? Regulates Mitochondrial Structure and Function and Human Pulmonary Artery Smooth Muscle Cell Proliferation. Am J Respir Cell Mol Biol 58:648-657
Vukelic, Sasa; Xu, Qian; Seidel-Rogol, Bonnie et al. (2018) NOX4 (NADPH Oxidase 4) and Poldip2 (Polymerase ?-Interacting Protein 2) Induce Filamentous Actin Oxidation and Promote Its Interaction With Vinculin During Integrin-Mediated Cell Adhesion. Arterioscler Thromb Vasc Biol 38:2423-2434
Hernandes, Marina S; Lass├Ęgue, Bernard; Hilenski, Lula L et al. (2018) Polymerase delta-interacting protein 2 deficiency protects against blood-brain barrier permeability in the ischemic brain. J Neuroinflammation 15:45
Okwan-Duodu, Derick; Hansen, Laura; Joseph, Giji et al. (2018) Impaired Collateral Vessel Formation in Sickle Cell Disease. Arterioscler Thromb Vasc Biol 38:1125-1133

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