Cytochrome P4501A1 and Vascular Injury

描述（由申请人提供）：全世界有超过10亿人吸烟。此外，据估计，仅在美国就有至少1.25亿儿童和不吸烟的成年人暴露在二手烟中。主动和被动暴露于烟草烟雾（TS）是心血管疾病（包括高血压）的主要危险因素。TS诱导的心血管损伤部分通过氧化应激介导。虽然TS是自由基的来源，但它也激活产生活性氧（ROS）的内源性途径。细胞色素P4501 A1（CYP 1A 1）是ROS的重要来源，在TS中的化学物质高度诱导血管系统中的一种酶。虽然已广泛研究了CYP 1A 1诱导对TS诱导的癌症的贡献，但尚未有研究调查内皮CYP 1A 1诱导对TS诱导的血管功能障碍和体内血流动力学改变的贡献。由于TS是一种高度复杂的化学物质混合物，因此很难剖析出任何单一下游途径的贡献或机制。为了应对这一挑战，我们开发了一种新的转基因小鼠模型，允许在血管系统中有条件地过表达CYP 1A 1，以解决CYP 1A 1诱导是体内血管功能障碍和高血压的独立风险因素的创新建议。我们的新的初步数据表明，过度表达的CYP 1A 1仅在内皮细胞诱导高血压和暴露的小鼠在TS中的单个化学品可能会导致激活的肾素-血管紧张素系统（RAS），血管功能和血压的主要调节。因此，我们将测试的假设，在血管内皮细胞中的CYP 1A 1的过度表达显着增加ROS诱导血管功能障碍和血管紧张素（Ang）II依赖性高血压。这一假设将在两个目标中进行检验，我们将（目标1）通过多次测量ROS和使用抗氧化剂或Ang II受体阻滞剂进行无线电遥测1治疗来测量血压，确定ROS和Ang II对血管内皮中CYP 1A 1过度表达诱导的高血压的作用，和（目的2）通过评估内皮细胞CYP 1A 1的过度表达，阐明内皮细胞CYP 1A 1的过度表达独立于血压升高而破坏血管功能的机制。在血压升高之前离体肠系膜动脉的依赖性扩张和收缩。该提案将确定诱导内皮细胞CYP 1A 1是体内血管功能障碍和血流动力学改变的独立介导者的程度，并将阐明其作为药物靶点预防主动和被动TS暴露诱导的血管疾病的潜力。

DESCRIPTION (provided by applicant): More than one billion people worldwide smoke cigarettes. In addition, it is estimated that there are at least 125 million children and non-smoking adults exposed to secondhand smoke in the U.S. alone. Both active and passive exposure to tobacco smoke (TS) is a major risk factor for cardiovascular disease, including hypertension. Cardiovascular injury induced by TS is mediated, in part, by oxidative stress. While TS is a source of free radicals, it also activates endogenous pathways that generate reactive oxygen species (ROS). One enzyme that is a significant source of ROS and is highly induced in the vasculature by chemicals in TS is cytochrome P4501A1 (CYP1A1). While the contribution of CYP1A1 induction to TS-induced cancer has been extensively studied, there have been no studies investigating the contribution of endothelial CYP1A1 induction to TS-induced vascular dysfunction and altered hemodynamics in vivo. Since TS is a highly complex mixture of chemicals, it is difficult to dissect out the contribution or mechanism of any single downstream pathway. To tackle this challenge we have developed a novel transgenic mouse model that allows for conditional over expression of CYP1A1 in the vasculature to address the innovative proposal that CYP1A1 induction is an independent risk factor for vascular dysfunction and hypertension in vivo. Our new preliminary data show that over expression of CYP1A1 solely in endothelial cells induces hypertension and exposure of mice to an individual chemical in TS may lead to activation of the renin-angiotensin system (RAS), a major regulator of vascular function and blood pressure. Thus, we will test the hypothesis that over expression of CYP1A1 in vascular endothelium significantly increases ROS which induce vascular dysfunction and angiotensin (Ang) II-dependent hypertension. This hypothesis will be tested in two aims where we will (Aim 1) establish the contribution of ROS and Ang II to hypertension induced by CYP1A1 over expression in vascular endothelium by multiple measurements of ROS and by measuring blood pressure with radiotelemetry 1 treatments with antioxidants or an Ang II receptor blocker, and (Aim 2) elucidate the mechanism by which endothelial CYP1A1 over expression disrupts vascular function independently of increases in blood pressure by evaluating endothelial-dependent dilation and constriction in mesenteric arteries ex vivo prior to increases in blood pressure. This proposal will establish the degree to which induction of endothelial CYP1A1 is an independent mediator of vascular dysfunction and altered hemodynamics in vivo and will elucidate its potential as a drug target to prevent vascular disease induced by both active and passive TS exposure.