Beta-arrestins regulate atherosclerosis and neointimal hyperplasia by controlling smooth muscle cell proliferation and migration.

Abstract

Atherosclerosis and arterial injury-induced neointimal hyperplasia involve medial smooth muscle cell (SMC) proliferation and migration into the arterial intima. Because many 7-transmembrane and growth factor receptors promote atherosclerosis, we hypothesized that the multifunctional adaptor proteins beta-arrestin1 and -2 might regulate this pathological process. Deficiency of beta-arrestin2 in ldlr(-/-) mice reduced aortic atherosclerosis by 40% and decreased the prevalence of atheroma SMCs by 35%, suggesting that beta-arrestin2 promotes atherosclerosis through effects on SMCs. To test this potential atherogenic mechanism more specifically, we performed carotid endothelial denudation in congenic wild-type, beta-arrestin1(-/-), and beta-arrestin2(-/-) mice. Neointimal hyperplasia was enhanced in beta-arrestin1(-/-) mice, and diminished in beta-arrestin2(-/-) mice. Neointimal cells expressed SMC markers and did not derive from bone marrow progenitors, as demonstrated by bone marrow transplantation with green fluorescent protein-transgenic cells. Moreover, the reduction in neointimal hyperplasia seen in beta-arrestin2(-/-) mice was not altered by transplantation with either wild-type or beta-arrestin2(-/-) bone marrow cells. After carotid injury, medial SMC extracellular signal-regulated kinase activation and proliferation were increased in beta-arrestin1(-/-) and decreased in beta-arrestin2(-/-) mice. Concordantly, thymidine incorporation and extracellular signal-regulated kinase activation and migration evoked by 7-transmembrane receptors were greater than wild type in beta-arrestin1(-/-) SMCs and less in beta-arrestin2(-/-) SMCs. Proliferation was less than wild type in beta-arrestin2(-/-) SMCs but not in beta-arrestin2(-/-) endothelial cells. We conclude that beta-arrestin2 aggravates atherosclerosis through mechanisms involving SMC proliferation and migration and that these SMC activities are regulated reciprocally by beta-arrestin2 and beta-arrestin1. These findings identify inhibition of beta-arrestin2 as a novel therapeutic strategy for combating atherosclerosis and arterial restenosis after angioplasty.

Department

Description

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Citation

Published Version (Please cite this version)

10.1161/CIRCRESAHA.108.172338

Publication Info

Kim, Jihee, Lisheng Zhang, Karsten Peppel, Jiao-Hui Wu, David A Zidar, Leigh Brian, Scott M DeWire, Sabrina T Exum, et al. (2008). Beta-arrestins regulate atherosclerosis and neointimal hyperplasia by controlling smooth muscle cell proliferation and migration. Circ Res, 103(1). pp. 70–79. 10.1161/CIRCRESAHA.108.172338 Retrieved from https://hdl.handle.net/10161/5911.

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Scholars@Duke

Zhang

Lisheng Zhang

Assistant Professor in Medicine

My research efforts involves studying the pathogenesis of vein graft neointimal hyperplasia and atherosclerosis.
The greatest amount of my time in the past years has been devoted to developing and characterizing our interposition vein graft model in mice. This model allows us to use IVC to carotid artery transplants between congenic mice. These transplants allow us to ask the questions about which gene products contribute to the pathogenesis of vein graft disease. In addition, I have used carotid artery to carotid artery transplants to study the role of TNF receptors in atherosclerosis. For these studies, we have used apolipoprotein E-deficient mice as graft recipients.
By using mouse vein graft model we demonstrate that most of the neointimal cells in vein grafts originate from cellular pools outside of the vein graft at the time of its implantation. The importance of this work relates to our persistent inability to treat vein graft disease in human beings. The second work demonstrates that expression of the tumor necrosis factor receptor-1, even in just in the vein graft cells themselves, contributes to the pathogenesis of vein graft neointimal hyperplasia. In this project, I surgically created chimeric mice to demonstrate molecular mechanisms by which the tumor necrosis factor receptor-1 aggravates neointimal hyperplasia, a process that is believed to lay the foundation for accelerated atherosclerosis in vein grafts.
I have also adapted my vein graft procedure in mice to ask questions about the arterial wall’s role in atherosclerosis. This atherosclerosis model involves making carotid interposition grafts not with veins, but with the carotid artery of congenic mice, and placing them into the carotid artery of spontaneously atherogenic mice that are deficient in apolipoprotein E.
I plan to continue our studies related to the role of inflammatory cytokine receptors in neointimal hyperplasia and atherosclerosis. In addition, I envision extending this work with the surgical models I have created in mice.

Lefkowitz

Robert J. Lefkowitz

The Chancellor's Distinguished Professor of Medicine

Dr. Lefkowitz’s memoir, A Funny Thing Happened on the Way to Stockholm, recounts his early career as a cardiologist and his transition to biochemistry, which led to his Nobel Prize win.

Robert J. Lefkowitz, M.D. is Chancellor’s Distinguished Professor of Medicine and Professor of Biochemistry and Chemistry at the Duke University Medical Center. He has been an Investigator of the Howard Hughes Medical Institute since 1976. Dr. Lefkowitz began his research career in the late 1960’s and early 1970’s when there was not a clear consensus that specific receptors for drugs and hormones even existed. His group spent 15 difficult years developing techniques for labeling the receptors with radioactive drugs and then purifying the four different receptors that were known and thought to exist for adrenaline, so called adrenergic receptors. In 1986 Dr. Lefkowitz transformed the understanding of what had by then become known as G protein coupled receptors because of the way the receptor signal for the inside of a cell through G proteins, when he and his colleagues cloned the gene for the beta2-adrenergic receptor. They immediately recognized the similarity to a molecule called rhodopsin which is essentially a light receptor in the retina. This unexpected finding established the beta receptor and rhodopsin as the first member of a new family of proteins. Because each has a peptide structure, which weaves across the cell membrane seven times, these receptors are referred to as seven transmembrane receptors. This super family is now known to be the largest, most diverse and most therapeutically accessible of all the different kinds of cellular receptors. There are almost a thousand members of this receptor family and they regulate virtually all known physiological processes in humans. They include the receptors not only to numerous hormones and neurotransmitters but for the receptors which mediate the senses of sweet and bitter taste and smell amongst many others. Dr. Lefkowitz also discovered the mechanism by which receptor signaling is turned off, a process known as desensitization. Dr. Lefkowitz work was performed at the most fundamental and basic end of the research spectrum and has had remarkable consequences for clinical medicine. Today, more than half of all prescription drug sales are of drugs that target either directly or indirectly the receptors discovered by Dr. Lefkowitz and his trainees. These include amongst many others beta blockers, angiotensin receptor blockers or ARBs and antihistamines. Over the past decade he has discovered novel mechanisms by which the receptors function which may lead to the development of an entirely new class of drugs called “biased agonists”. Several such compounds are already in advanced stages of clinical testing. Dr. Lefkowitz has received numerous honors and awards, including the National Medal of Science, the Shaw Prize, the Albany Prize, and the 2012 Nobel Prize in Chemistry. He was elected to the USA National Academy of Sciences in 1988, the Institute of Medicine in 1994, and the American Academy of Arts and Sciences in 1988.

Freedman

Neil Jonathan Freedman

Professor of Medicine

Our work focuses on atherosclerosis-related signal transduction and the genetic bases of atherosclerosis and vein graft failure, both in vitro and in vivo. We investigate the regulation of receptor protein tyrosine kinases by G protein-coupled receptor kinases (GRKs), and the role of GRKs and β-arrestins in atherosclerosis; the role of tumor necrosis factor and its receptors in atherosclerosis; and the role of the dual Rho-GEF kalirin in atherosclerosis. For in vivo modeling of atherosclerosis and neointimal hyperplasia, we use mouse carotid artery bypass grafting with either veins or arteries from gene-deleted or congenic wild type mice, as well as aortic atherosclerosis studies and bone marrow transplantation. To study receptor phosphorylation, signal transduction, and intracellular trafficking, we employ primary smooth muscle cells, endothelial cells, and macrophages derived from knockout mice or treated with RNA interference.

Key Words: atherosclerosis, G protein-coupled receptor kinases, arrestins, desensitization, phosphorylation, platelet-derived growth factor receptors, receptor protein tyrosine kinases, smooth muscle cells, neointimal hyperplasia, Rho-GEF.


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