Laminar shear stress protects arterial wall from the development of atherosclerotic plaques by controlling the structure and function of endothelial cells. The anti-atherogenic effects of laminar shear involve production of vasoactive factors such as NO, reactive oxygen species (ROS) and reactive nitrogen species (RNS) in endothelial cells. However, the mechanisms 1) by which laminar shear stimulates production of NO from eNOS, ROS from NADPH oxidases, and their reaction products, RNS, and 2) by which these free radicals mediate the anti-atherogenic effects of laminar shear are not known. As detailed in the Preliminary results, our recent results strongly suggest that shear stress regulates eNOS activity by an unexpected mechanisms. Unlike the previous assumption that protein kinase B(Akt) would be the protein kinase responsible for phosphorylation of eNOS at Ser1179 resi8due, we show that other kinases such as protein kinase A is responsible for phosphorylation of eNOS-Ser1179. Considering the presence of multiple potential phosphorylation sites found in eNOS, it is important to res examine the detailed mechanisms by which phosphorylation/dephosphorylation regulate eNOS in response to shear. To address these questions, we have developed mouse aortic endothelial cells from normal and several knockout (KO) mice deficient in eNOS and NADPH oxidase components (gp 91 and p47). Using these endothelial cells as well as the eNOS-KO cells transfected with mutated eNOS constructs, we will examines the hypotheses 1) that laminar shear stimulates NO production by controlling by phosphorylation of key regulatory sites of eNOS by the phosphatidyl-3-kinase and protein kinase A-dependent mechanisms, and 2) that shear prevents endothelial cell death induced by pro-atherogenic factors by the NO, ROS, and RNS- dependent mechanisms. These hypotheses will be examined by following the four aims:
Aim 1 : Determine the signaling pathways regulating shear- dependent phosphorylation and activation of eNOS.
Aim 2 : Determine the effect of laminar shear on RNS productions.
Aim 4 : Define the role of NO and RNS in laminar shear-dependent, anti-atherogenic responses of endothelial cells.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL071014-03
Application #
6781854
Study Section
Pathology A Study Section (PTHA)
Program Officer
Srinivas, Pothur R
Project Start
2002-08-01
Project End
2006-07-31
Budget Start
2004-08-01
Budget End
2005-07-31
Support Year
3
Fiscal Year
2004
Total Cost
$304,000
Indirect Cost
Name
Emory University
Department
Biomedical Engineering
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Arjunon, Sivakkumar; Rathan, Swetha; Jo, Hanjoong et al. (2013) Aortic valve: mechanical environment and mechanobiology. Ann Biomed Eng 41:1331-46
Kang, Dong Hoon; Lee, Doo Jae; Kim, Jiran et al. (2013) Vascular injury involves the overoxidation of peroxiredoxin type II and is recovered by the peroxiredoxin activity mimetic that induces reendothelialization. Circulation 128:834-44
Fazeli, Gholamreza; Stopper, Helga; Schinzel, Reinhard et al. (2012) Angiotensin II induces DNA damage via AT1 receptor and NADPH oxidase isoform Nox4. Mutagenesis 27:673-81
Huh, Joo Young; Son, Dong Ju; Lee, Yoonji et al. (2012) 8-Hydroxy-2-deoxyguanosine prevents plaque formation and inhibits vascular smooth muscle cell activation through Rac1 inactivation. Free Radic Biol Med 53:109-21
Boo, Yong Chool; Mun, Gyeong In; Tressel, Sarah L et al. (2011) Detection of low levels of nitric oxide using an electrochemical sensor. Methods Mol Biol 704:81-9
Park, Jong-Gil; Yoo, Ji-Young; Jeong, Se-Jin et al. (2011) Peroxiredoxin 2 deficiency exacerbates atherosclerosis in apolipoprotein E-deficient mice. Circ Res 109:739-49
Yin, Weiwei; Jo, Hanjoong; Voit, Eberhard O (2010) Systems analysis of the role of bone morphogenic protein 4 in endothelial inflammation. Ann Biomed Eng 38:291-307
Dhawan, Saurabh S; Avati Nanjundappa, Ravi P; Branch, Jonathan R et al. (2010) Shear stress and plaque development. Expert Rev Cardiovasc Ther 8:545-56
Sucosky, Philippe; Balachandran, Kartik; Elhammali, Adnan et al. (2009) Altered shear stress stimulates upregulation of endothelial VCAM-1 and ICAM-1 in a BMP-4- and TGF-beta1-dependent pathway. Arterioscler Thromb Vasc Biol 29:254-60
Patel, Mamta J; Chang, Kyungh Hwa; Sykes, Michelle C et al. (2009) Low magnitude and high frequency mechanical loading prevents decreased bone formation responses of 2T3 preosteoblasts. J Cell Biochem 106:306-16

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