Atherosclerosis is a chronic disease of arterial wall caused by various genetic and environmental risk factors and is the foremost cause of mortality worldwide. Inflammation plays a critical role in atherogenesis. Protease- activated receptor 1 (Par1) that mediates the cellular effects of thrombin, a serine protease, has been reported to play an important role in inflammation. In addition, a large body of data suggests that Par1 plays an essential role in atherothrombosis. Despite the role of Par1 in inflammation and atherothrombosis and the fact that increased expression of Par1 is observed in atherosclerotic plaques, nothing is known about its role in atherogenesis. In this context, we recently discovered that thrombin induces the expression of CD36, a scavenger receptor linked to oxLDL uptake and foam cell formation, and this event requires G?12/13, Pyk2, Gab1, PKC? and ATF2 activation downstream to Par1. In addition, we found that thrombin induces the depletion of ABCA1, a reverse cholesterol transporter and attenuates cholesterol efflux. Interestingly, ABCA1 was found to exist in complex with GSK3? and, upon treatment with thrombin, it dissociates from GSK3?, associates with cullin 3, a component of E3 ligases, and undergoes degradation. Based on these novel observations, we hypothesize that thrombin-Par1 axis plays a major role in atherogenesis. To test this central hypothesis, we propose to address the following three specific aims:
Specific Aim 1 : Par1 plays a central role in atherogenesis.
Specific Aim 2 : PKC? via activating ATF2 and enhancing CD36 expression, oxLDL uptake and foam cell formation plays a crucial role in atherogenesis.
Specific Aim 3 : Overexpression of GSK3? stabilizes ABCA1, enhances cholesterol efflux and protects from atherogenesis. The results of the proposed studies will provide new mechanistic insights into the pathophysiology of atherosclerosis and explore the translational impact of thrombin-Par1 signaling in this debilitating vascular disease.

Public Health Relevance

Atherosclerosis and its lesion related thrombosis are the foremost causes of myocardial infarction and stroke, which together constitute the major cause of death in the western society. Despite the importance of thrombin in thrombus formation, its role in atherogenesis is not known. Towards this end, the experiments proposed in this grant application will provide novel insights on the involvement of thrombin and its receptor, Par1, in the pathophysiology of atherosclerosis.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL103575-09
Application #
9724510
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Gao, Yunling
Project Start
2011-04-01
Project End
2021-06-30
Budget Start
2019-07-01
Budget End
2021-06-30
Support Year
9
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Physiology
Type
Schools of Medicine
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38103
Raghavan, Somasundaram; Singh, Nikhlesh K; Mani, Arul M et al. (2018) Protease-activated receptor 1 inhibits cholesterol efflux and promotes atherogenesis via cullin 3-mediated degradation of the ABCA1 transporter. J Biol Chem 293:10574-10589
Janjanam, Jagadeesh; Zhang, Baolin; Mani, Arul M et al. (2018) LIM and cysteine-rich domains 1 is required for thrombin-induced smooth muscle cell proliferation and promotes atherogenesis. J Biol Chem 293:3088-3103
Raghavan, Somasundaram; Singh, Nikhlesh K; Gali, Sivaiah et al. (2018) Protein Kinase C? Via Activating Transcription Factor 2-Mediated CD36 Expression and Foam Cell Formation of Ly6Chi Cells Contributes to Atherosclerosis. Circulation 138:2395-2412
Kotla, Sivareddy; Singh, Nikhlesh K; Kirchhofer, Daniel et al. (2017) Heterodimers of the transcriptional factors NFATc3 and FosB mediate tissue factor expression for 15(S)-hydroxyeicosatetraenoic acid-induced monocyte trafficking. J Biol Chem 292:14885-14901
Janjanam, Jagadeesh; Rao, Gadiparthi N (2016) Novel role of cortactin in G protein-coupled receptor agonist-induced nuclear export and degradation of p21Cip1. Sci Rep 6:28687
Janjanam, Jagadeesh; Chandaka, Giri Kumar; Kotla, Sivareddy et al. (2015) PLC?3 mediates cortactin interaction with WAVE2 in MCP1-induced actin polymerization and cell migration. Mol Biol Cell 26:4589-606
Singh, Nikhlesh K; Kotla, Sivareddy; Dyukova, Elena et al. (2015) Disruption of p21-activated kinase 1 gene diminishes atherosclerosis in apolipoprotein E-deficient mice. Nat Commun 6:7450
Gadepalli, Ravisekhar; Kotla, Sivareddy; Heckle, Mark R et al. (2013) Novel role for p21-activated kinase 2 in thrombin-induced monocyte migration. J Biol Chem 288:30815-31
Kundumani-Sridharan, Venkatesh; Singh, Nikhlesh K; Kumar, Sanjay et al. (2013) Nuclear factor of activated T cells c1 mediates p21-activated kinase 1 activation in the modulation of chemokine-induced human aortic smooth muscle cell F-actin stress fiber formation, migration, and proliferation and injury-induced vascular wall remodeli J Biol Chem 288:22150-62
Keilani, Serene; Chandwani, Samira; Dolios, Georgia et al. (2012) Egr-1 induces DARPP-32 expression in striatal medium spiny neurons via a conserved intragenic element. J Neurosci 32:6808-18

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