Arterial stiffening, manifested by thickening and reduced elasticity of conduit arteries, is an independent risk factor for stroke and heart disease. Although the etiology of arterial stiffening correlates well with aging, the underlying cellular and molecular basis remains unclear. In vivo, hemodynamic forces dynamically act on the vascular wall, which greatly affect arterial function and mechanical properties. Arterial stiffening may involves aberrant endothelial response to shear stress resulted from these hemodynamic forces. We recently found that SIRT1, an anti-aging regulator is modulated by shear stress in vascular endothelial cells (ECs). Moreover, calmodulin-dependent protein kinase (CaMKK) appears to be a shear stress-sensitive kinase that regulates SIRT1. We thus hypothesize that shear stress upregulates SIRT1 in the endothelium of conduit arteries, which ameliorates pathophysiological remodeling leading to arterial stiffening. At the upstream, CaMKKb is activated in response to the physiologically relevant shear stress. As a consequence of the activated CaMKKb-SIRT1 pathway, the endothelial nitric oxide synthase (eNOS)-derived NO bioavailability and PGC-1a-regulated ROS scavenger expression are augmented. Thus, the advantageous effects of shear stress-augmented SIRT1 include decreased oxidative stress and remodeling of extracellular matrices. To test our hypothesis, three Specific Aims are proposed.
Specific Aim 1 will examine the hemodynamic factors critical for the induction of SIRT1 in cultured ECs. Molecular signaling experiments will then be conducted to study the mechanism by which CaMKKb regulates SIRT1 in ECs responding to the defined shear stress.
Specific Aim 2 will elucidate the cellular and molecular mechanisms by which shear stress-induced SIRT1 exerts anti- stiffening effects in an EC/vascular smooth muscle cell co-culture system. We will decipher the synergistic effect of SIRT1 and AMP-activated protein kinase (AMPK) in eNOS-derived NO bioavailability and PGC-1a-regulated reactive oxygen species (ROS) scavengers.
Specific Aim 3 will investigate the role of shear stress-activated SIRT1 in arterial stiffening in mouse models. Specifically, we will compare the spatiotemporal changes of arterial stiffening in EC-sirt1-/- knockout, Tg-EC-sirt1, and CaMKKb-/- mice. The arterial stiffening-associated changes in hemodynamic factors, aortic wall remodeling, and gene expression profiles will be measured and correlated. Results from these proposed studies, if as anticipated, will help to understand the mechano and molecular basis of arterial stiffening.

Public Health Relevance

Arterial stiffening, associated with the aging process, is an independent risk factor for many cardiovascular diseases. SIRT1 is a master regulator involved in many anti-stress responses and we recently found that hemodynamic force can activate SIRT1 in vascular cells. This proposed study will investigate the mechano and molecular basis of flow induction of SIRT1, which would be anti-arterial stiffening. The proposal will significantly increase our understanding of mechanisms by which blood flow interplays with aging process in arterial stiffening. Results from the proposed experiments are likely to contribute to novel therapies for its prevention and/or treatment.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
1R01HL105318-01
Application #
8016341
Study Section
Special Emphasis Panel (ZHL1-CSR-W (S1))
Program Officer
Thrasher, Terry N
Project Start
2010-09-20
Project End
2014-06-30
Budget Start
2010-09-20
Budget End
2011-06-30
Support Year
1
Fiscal Year
2010
Total Cost
$380,000
Indirect Cost
Name
University of California Riverside
Department
Type
Schools of Medicine
DUNS #
627797426
City
Riverside
State
CA
Country
United States
Zip Code
92521
Zhang, Jiao; Yin, Yanjun; Chen, Lili et al. (2018) Short-Term High-Salt Diet Increases Corin Level to Regulate the Salt-Water Balance in Humans and Rodents. Am J Hypertens 31:253-260
Zhang, Jiao; Dong, Jianjie; Martin, Marcy et al. (2018) AMP-activated Protein Kinase Phosphorylation of Angiotensin-Converting Enzyme 2 in Endothelium Mitigates Pulmonary Hypertension. Am J Respir Crit Care Med 198:509-520
Li, Zhao; Martin, Marcy; Zhang, Jin et al. (2017) Krüppel-Like Factor 4 Regulation of Cholesterol-25-Hydroxylase and Liver X Receptor Mitigates Atherosclerosis Susceptibility. Circulation 136:1315-1330
Shentu, Tzu-Pin; He, Ming; Sun, Xiaoli et al. (2016) AMP-Activated Protein Kinase and Sirtuin 1 Coregulation of Cortactin Contributes to Endothelial Function. Arterioscler Thromb Vasc Biol 36:2358-2368
Chen, Zhen; Wen, Liang; Martin, Marcy et al. (2015) Oxidative stress activates endothelial innate immunity via sterol regulatory element binding protein 2 (SREBP2) transactivation of microRNA-92a. Circulation 131:805-14
Chen, Zhen; Martin, Marcy; Li, Zhao et al. (2014) Endothelial dysfunction: the role of sterol regulatory element-binding protein-induced NOD-like receptor family pyrin domain-containing protein 3 inflammasome in atherosclerosis. Curr Opin Lipidol 25:339-49
Xiao, Han; Lu, Min; Lin, Ting Yang et al. (2013) Sterol regulatory element binding protein 2 activation of NLRP3 inflammasome in endothelium mediates hemodynamic-induced atherosclerosis susceptibility. Circulation 128:632-42
Chen, Zhen; Shentu, Tzu-Pin; Wen, Liang et al. (2013) Regulation of SIRT1 by oxidative stress-responsive miRNAs and a systematic approach to identify its role in the endothelium. Antioxid Redox Signal 19:1522-38
Chen, Zhen; Lai, Tsung-Ching; Jan, Yi-Hua et al. (2013) Hypoxia-responsive miRNAs target argonaute 1 to promote angiogenesis. J Clin Invest 123:1057-67
Wen, Liang; Chen, Zhen; Zhang, Fan et al. (2013) Ca2+/calmodulin-dependent protein kinase kinase ? phosphorylation of Sirtuin 1 in endothelium is atheroprotective. Proc Natl Acad Sci U S A 110:E2420-7

Showing the most recent 10 out of 12 publications