The proposed studies will focus on the signaling cascade responsible for the estrogen- and shear stress-specific regulation of cytochrome P450 (CYP) gene and protein expression, leading to an enhanced release of EETs to dilate/hyperpolarize vessels that are deficienct in NO.
Two specific aims are proposed related to 1) estrogen specific pathways and 2) shear stress- dependent pathways. Studies will be conducted on isolated arteries of endothelial nitric oxide knockout (eNOS-KO) and estrogen receptor (ER)-KO mice. Specific CYP family/subfamily gene expression, protein synthesis and EET regioisomers responsible for EET-mediation of flow-induced dilation/hyperpolarization in vessels that have been exposed to estrogen (Specific Aim 1) or shear stress (Specific Aim 2) will be assessed by using microarray/real time RT-PCR, molecular (western blotting and immunohistochemistry) and fluorescence HPLC analyses. The specific target for EETs will be determined by patch-clamp techniques. By using a newly designed vessel culture technique, an RNA interference (RNAi) study will be performed to confirm the functional significance of the gene(s)/protein(s)/product(s) detected in the vessels, by comparison of flow-induced dilation/hyperpolarization in intact vessels before and after transfection of the vessels with specific siRNA. Moreover, roles of tyrosine kinases/MAPK pathway, as one of the most characterized extranuclear signaling actions of estrogen in the regulation of CYP expression and its dowmstream located specific transcription factor(s) will also be assessed. In addition, as a consequence of activation of CYP, the impact of superoxide/hydrogen peroxide on estrogen- and shear stress-specific signaling cascades will be evaluated. The interactions among the two pathways will be clarified by comparison of the responses of vessels treated with a single stimulus (e.g. estrogen, or shear stress) with those treated with combined stimuli (e.g. estrogen plus shear stress). Also, the specific role of ERs in the estrogen-specific pathway involving the regulation of CYP will be assessed by comparison of the responses observed from vessels that are absent in ER? or ER? with those of wild type controls. The knowledge generated by these studies will unravel a novel therapeutic target to improve vascular endothelial function by the upregulation of CYP-dependent dilator pathways as an adaptation to NO deficiency.

Public Health Relevance

The endothelium is the inner layer of blood vessels. Endothelial cells release vasoactive factors (agents) when they are stimulated by estrogen or shear stress. Estrogen(s) is a female hormone(s) that is primarily produced by the female reproductive system, such as the ovaries. Shear stress is the mechanical force on the endothelium when blood flows through the vessels. The factors released from endothelial cells can dilate (enlarge) the vessels, leading to greater blood supply to organs/tissues. Thus, this project is to study how endothelial cells release the agents when stimulated with estrogen and shear stress.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL070653-08
Application #
8206735
Study Section
Hypertension and Microcirculation Study Section (HM)
Program Officer
Mcdonald, Cheryl
Project Start
2002-07-01
Project End
2013-12-31
Budget Start
2012-01-01
Budget End
2013-12-31
Support Year
8
Fiscal Year
2012
Total Cost
$278,250
Indirect Cost
$103,250
Name
New York Medical College
Department
Physiology
Type
Schools of Medicine
DUNS #
041907486
City
Valhalla
State
NY
Country
United States
Zip Code
10595
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Huang, An; Yan, Changdong; Suematsu, Nobuhiro et al. (2010) Impaired flow-induced dilation of coronary arterioles of dogs fed a low-salt diet: roles of ANG II, PKC, and NAD(P)H oxidase. Am J Physiol Heart Circ Physiol 299:H1476-83
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Heylen, Erwan; Huang, An; Sun, Dong et al. (2009) Nitric oxide-mediated dilation of arterioles to intraluminal administration of aldosterone. J Cardiovasc Pharmacol 54:535-42
Yan, Changdong; Huang, An; Kaley, Gabor et al. (2007) Chronic high blood flow potentiates shear stress-induced release of NO in arteries of aged rats. Am J Physiol Heart Circ Physiol 293:H3105-10
Jacobson, Azita; Yan, Changdong; Gao, Qun et al. (2007) Aging enhances pressure-induced arterial superoxide formation. Am J Physiol Heart Circ Physiol 293:H1344-50
Sun, Dong; Yan, Changdong; Jacobson, Azita et al. (2007) Contribution of epoxyeicosatrienoic acids to flow-induced dilation in arteries of male ERalpha knockout mice: role of aromatase. Am J Physiol Regul Integr Comp Physiol 293:R1239-46

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