This is a proposal to investigate the role of protein tyrosine phosphatase PTP1B as mediator of the inhibitory effects of nitric oxide (NO) in vascular smooth muscle and in vascular remodeling. NO plays a major inhibitory role in neointima formation after vascular injury. Mechanisms explaining this effect in cultured cells and especially in vivo are lacking. We have found that NO increases the activity of PTP1B in cultured rat aortic smooth muscle cells, without increasing its protein levels. Moreover, we have found that PDGF and FGF increase PTP1B protein levels in cultured cells and that vascular injury similarly induces increased PTP1B protein levels in injured rat carotid artery. We have also shown that NO targets the IGF1 receptor, inducing receptor tyrosine dephosphorylation and interrupting IGF1-induced signal transduction in cultured cells. Finally, we have shown that NO decreases cytoplasmic Ca and attenuates IGF1-induced hydrogen peroxide generation and that this effect is mimicked by independent lowering of intracellular Ca by a Ca chelator. These results support a possible involvement of reduced Ca in activating PTP1B. The role of IGF1 in vascular injury is currently unclear. On the one hand, vascular injury induces upregulation of IGF1 levels but on the other, IGF1 receptor mRNA levels and IGF1 receptor binding are decreased. Consistent with these findings, we have found that vascular injury decreases IGF1 receptor protein levels by about 30%, as determined by Western blot analysis; moreover, we have found that receptor activation, as measured by specific receptor tyrosine phosphorylation, is decreased by more than 80%. These novel and exciting findings describe for the first time a mechanistic link between NO and tyrosine kinase receptor dephosphorylation involving a protein tyrosine phosphatase. Taken together, our results raise the possibility of negative cross-talk between, on the one hand PDGF or FGF, and on the other IGF1 signal transduction, via the intermediacy of elevated PTP1B. Based on the above, we propose the following specific aims, to be performed in cultured rat aortic smooth muscle cells or in rats or mice: Determine whether reduction of cytoplasmic Ca is necessary and/or sufficient to induce upregulation of PTP1B activity. Determine whether upregulation of PTP1B is necessary and/or sufficient to account for NO-induced inhibition of cell proliferation and induction of apoptosis in cultured cells. Determine whether PDGF, FGF or NO induces upregulation of PTP1B protein or activity levels in vascular injury. Determine whether PTP1B plays a role in NO-induced decrease of cell proliferation, motility, apoptosis and neointima formation in models of rat or mouse vascular injury. Determine whether PTP1B plays a role in attenuating IGF receptor activation in vivo. ? ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL072902-04
Application #
7234796
Study Section
Vascular Cell and Molecular Biology Study Section (VCMB)
Program Officer
Goldman, Stephen
Project Start
2004-07-01
Project End
2009-06-30
Budget Start
2007-07-01
Budget End
2009-06-30
Support Year
4
Fiscal Year
2007
Total Cost
$346,086
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
38163
Zhuang, Daming; Balani, Poonam; Pu, Qinghua et al. (2011) Suppression of PKG by PDGF or nitric oxide in differentiated aortic smooth muscle cells: obligatory role of protein tyrosine phosphatase 1B. Am J Physiol Heart Circ Physiol 300:H57-63
Pu, Qinghua; Zhuang, Daming; Thakran, Shalini et al. (2011) Mechanisms related to NO-induced motility in differentiated rat aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 300:H101-8
Pu, Qinghua; Chang, Yingzi; Zhang, Chunxiang et al. (2009) Chronic insulin treatment suppresses PTP1B function, induces increased PDGF signaling, and amplifies neointima formation in the balloon-injured rat artery. Am J Physiol Heart Circ Physiol 296:H132-9
Xi, Qi; Adebiyi, Adebowale; Zhao, Guiling et al. (2008) IP3 constricts cerebral arteries via IP3 receptor-mediated TRPC3 channel activation and independently of sarcoplasmic reticulum Ca2+ release. Circ Res 102:1118-26
Zhuang, Daming; Pu, Qinghua; Ceacareanu, Bogdan et al. (2008) Chronic insulin treatment amplifies PDGF-induced motility in differentiated aortic smooth muscle cells by suppressing the expression and function of PTP1B. Am J Physiol Heart Circ Physiol 295:H163-73
Desai, Leena P; Sinclair, Scott E; Chapman, Kenneth E et al. (2007) High tidal volume mechanical ventilation with hyperoxia alters alveolar type II cell adhesion. Am J Physiol Lung Cell Mol Physiol 293:L769-78
Ceacareanu, Alice-Corina; Ceacareanu, Bogdan; Zhuang, Daming et al. (2006) Nitric oxide attenuates IGF-I-induced aortic smooth muscle cell motility by decreasing Rac1 activity: essential role of PTP-PEST and p130cas. Am J Physiol Cell Physiol 290:C1263-70
Yang, Jian; Cheng, Yunhui; Ji, Ruirui et al. (2006) Novel model of inflammatory neointima formation reveals a potential role of myeloperoxidase in neointimal hyperplasia. Am J Physiol Heart Circ Physiol 291:H3087-93
Yang, Jian; Ji, Ruirui; Cheng, Yunhui et al. (2006) L-arginine chlorination results in the formation of a nonselective nitric-oxide synthase inhibitor. J Pharmacol Exp Ther 318:1044-9
Chang, Yingzi; Ceacareanu, Bogdan; Zhuang, Daming et al. (2006) Counter-regulatory function of protein tyrosine phosphatase 1B in platelet-derived growth factor- or fibroblast growth factor-induced motility and proliferation of cultured smooth muscle cells and in neointima formation. Arterioscler Thromb Vasc Biol 26:501-7

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