Characterization And Functional Significance Of P450 Arachidonate Epoxygenases

细胞色素P450将花生四烯酸（AA）代谢为环氧二碳三烯酸（EETs），对心血管和肾脏功能有重要影响。eet通过微粒体环氧化物水解酶（mEH）和可溶性环氧化物水解酶（sEH）代谢成相应的二醇（DHETs）。目前的研究主要包括：(1)在生化和分子水平上对CYP2J和CYP2C亚家族p450进行表征；(2) CYP2J产物在心血管和肾脏生理中的功能作用评价；(3)环氧化物水解酶在心血管生理中的功能作用评价；(4)在选定的人类疾病（缺血性心脏病、高血压、动脉粥样硬化、癌症）动物模型中检测这一途径；(5)评估人类CYP2C、CYP2J、sEH和mEH基因多态性对心血管功能和疾病的影响。我们已经发现了许多哺乳动物的CYP2Js，尽管我们的大部分工作都集中在人类CYP2J2和小鼠CYP2J5上。人CYP2J2是主要表达于心脏和血管系统的P450蛋白，定位于心肌细胞和内皮细胞，在AA到eet的代谢中具有活性。cyp2j2衍生的eet具有血管扩张剂作用，抑制细胞因子诱导的内皮细胞粘附分子表达，诱导组织纤溶酶原激活物基因表达，抑制血管平滑肌细胞迁移，保护内皮细胞缺氧复氧损伤和凋亡，上调内皮一氧化氮生物合成，影响心脏电生理，保护心脏免受缺血性损伤。建立CYP2J2转基因小鼠（α -肌球蛋白重链启动子驱动心脏特异性表达），研究EETs增加对心脏功能的影响。这些小鼠的心脏基础解剖和功能正常，缺血后左心室功能改善，心脏动作电位缩短，心脏电生理改变，β -肾上腺素能受体反应性增强。同样，EET水解减少的sEH缺失小鼠具有改善的缺血后功能恢复。我们发现mEH在体内调节EET水平，mEH/sEH双缺失小鼠的心脏功能比sEH缺失小鼠的心脏功能恢复得更快。我们还开发了转基因小鼠，其中CYP2J2， CYP2C8或sEH仅在内皮细胞中表达（Tie2启动子驱动），以研究这些酶及其产物在血管功能中的作用。内皮细胞表达CYPs或sEH调节血管生成，促进肿瘤的形成和生长，调节视网膜血管化。人类CYP2J2基因已被克隆、测序和鉴定。我们已经确定了几个功能相关的CYP2J2多态性变异，其中一个与CYP2J2表达减少有关，并且在几个队列中与心血管疾病的风险相关。我们还发现了sEH基因的功能相关多态性，并在美国的一个大型多种族队列中表明它们与心血管疾病风险相关。CYP2J5是一种主要的小鼠P450花生四烯酸环氧化酶，在肾脏中表达并定位于近端小管。CYP2J5缺失小鼠在高盐和低盐饮食中都存在自发性高血压。与这些发现一致，我们在田纳西州的一个队列中发现CYP2J2多态性变异与高血压之间存在关联。鉴于sEH抑制剂（sEHis）的抗炎作用，我们研究了sEHis在衰减sars - cov -2诱导的类二十烷和细胞因子风暴中的作用。

Cytochromes P450 metabolize arachidonic acid (AA) to epoxyeicosatrienoic acids (EETs) which have potent effects on cardiovascular and renal function. EETs are metabolized to corresponding diols (DHETs) by microsomal epoxide hydrolase (mEH) and soluble epoxide hydrolase (sEH). Current research involves: (1) characterization of CYP2J and CYP2C subfamily P450s at the biochemical and molecular levels; (2) evaluation of the functional roles of CYP2J products in cardiovascular and renal physiology; (3) evaluation of the functional roles of epoxide hydrolases in cardiovascular physiology; (4) examination of this pathway in selected animal models of human disease (ischemic heart disease, hypertension, atherosclerosis, cancer), and (5) evaluation of the effect of human polymorphisms in genes for CYP2C, CYP2J, sEH and mEH on cardiovascular function and disease. We have discovered a number of mammalian CYP2Js, although we have focused most of our efforts on human CYP2J2 and mouse CYP2J5. Human CYP2J2 is the major human P450 expressed in heart and vasculature, where it is localized to cardiac myocytes and endothelial cells, and is active in the metabolism of AA to EETs. CYP2J2-derived EETs are vasodilators, inhibit cytokine-induced endothelial cell adhesion molecule expression, induce tissue plasminogen activator gene expression, inhibit vascular smooth muscle cell migration, protect endothelial cells against hypoxia-reoxygenation injury and apoptosis, upregulate endothelial nitric oxide biosynthesis, affect cardiac electrophysiology, and protect the heart from ischemic injury. CYP2J2 transgenic mice (alpha-myosin heavy chain promoter driven cardiac-specific expression) were developed to study the effects of increased EETs on cardiac function in vivo. These mice have normal basal heart anatomy and function, improved post-ischemic left ventricular function, shortened cardiac action potential, altered cardiac electrophysiology, and enhanced beta-adrenergic receptor responsiveness. Similarly, sEH null mice which exhibit reduced EET hydrolysis have improved postischemic functional recovery. We discovered that mEH regulates EET levels in vivo and that hearts from mEH/sEH double-null mice have greater recovery of heart function relative to hearts from sEH null mice. We have also developed transgenic mice in which CYP2J2, CYP2C8 or sEH are expressed exclusively in endothelial cells (Tie2 promoter driven) to examine the role of these enzymes and their products on vascular function. Endothelial expression of CYPs or sEH regulate angiogenesis which promotes tumor formation and growth and regulates retinal vascularization. The human CYP2J2 gene has been cloned, sequenced and characterized. We have identified several functionally relevant CYP2J2 polymorphic variants, one of which is associated with reduced CYP2J2 expression and is associated with risk of cardiovascular disease in several cohorts. We have also identified functionally relevant polymorphisms in the sEH gene and have shown that they are associated with cardiovascular disease risk in a large multiethnic cohort in the U.S. CYP2J5 is a major murine P450 arachidonic acid epoxygenase expressed in the kidney and localized to proximal tubules. CYP2J5 null mice have spontaneous hypertension that persists on both high and low salt diets. Consistent with these findings, we have shown that there is an association between CYP2J2 polymorphic variants and hypertension in a cohort from Tennessee. Given the anti-inflammatory effects of sEH inhibitors (sEHis), we have examined the role of sEHis in attenuation of SARS-CoV-2-induced eicosanoid and cytokine storm. This project involves research on human coronavirus, novel coronavirus, COVID-19, Severe Acute Respiratory Syndrome coronavirus disease, SARS coronavirus, SARS-coronavirus-2, SARS-cov-2, SARS-cov2, SARS-related coronavirus 2, Severe acute respiratory syndrome coronavirus 2, SARS-Associated Coronavirus, SARS-cov, or SARS-Related Coronavirus.