CORNEAL ARACHIDONATE METABOLITES VIA CYTOCHROME P450

这是一个继续表征眼生物合成的建议， 新型细胞色素P450（P450）花生四烯酸（AA）的代谢归宿 代谢物，确定其生物活性并评估其 在正常和病理生理条件下， （炎症）状态和房水动力学。前一 在本研究期间，我们证明了人、兔和 牛眼通过P450途径将AA代谢为几种含氧化合物 代谢物。其中两个化合物经纯化后，用GC/MS鉴定 结合生物测定的分析：12（R）HETE和12（R）DH-HETE。我们发现 12（R）HETE是一种有效的Na，K-ATP酶抑制剂，并证明它 降低兔眼内压（IOP），表明它是一种 眼房水动力学的内源性角膜调节剂。角膜 透明和房水分泌是 依赖于Na，K-ATP酶活性。我们假设12（R）HETE作为一种 内源性Na，K-ATP酶抑制剂调节眼内的这些过程 因此有助于维持角膜透明度， IOP。另一方面，12（R）DH-HETE是一种强大的促炎剂， 化合物;它扩张血管，增加膜渗透性， 刺激中性粒细胞迁移并产生新血管形成。效果 12（R）DH-HETE对兔眼的刺激模拟了眼对12（R）DH-HETE的反应。 炎症刺激血管扩张，血液水化 屏障和新血管形成是眼内炎症的众所周知的后果。 炎症我们假设通常发生的炎症 角膜损伤后，部分是通过释放 12（R）DH-HETE由角膜上皮产生。这些炎症 结果是眼睛中许多病理过程的共同事件 除了角膜上皮损伤之外这将是感兴趣的 未来将调查12（R）DH-HETE参与的条件，如 葡萄膜炎、年龄相关性黄斑变性和糖尿病视网膜病变。到 评估这些新代谢物在眼功能中的重要性， 关于生物化学和作用机制的某些问题 必须解决这些化合物。特别是， 导致其形成的酶促步骤，其代谢降解， 眼组织以及其他眼组织是否具有 在对他们的治疗效果进行评估之前， 潜力可以发挥。

This is a proposal to continue characterizing the ocular biosynthesis and metabolic fate of the novel cytochrome P450 (P450) arachidonic acid (AA) metabolites, determining their biological activities and evaluating their contribution to corneal function and under normal and pathophysiological (inflammation) states and to aqueous humor dynamics. During the preceding grant period, we demonstrated that corneal epithelium of human, rabbit and bovine eyes metabolizes AA via the P450 pathway to several oxygenated metabolites. Two of them have been purified and identified by GC/MS analysis coupled to bioassays: 12(R)HETE and 12(R)DH-HETE. We found that 12(R)HETE is a potent Na, K-ATPase inhibitor and demonstrated that it reduces intraocular pressure (IOP) in rabbits, suggesting it is an endogenous corneal modulator of aqueous humor dynamics. Corneal transparency and aqueous humor secretion are examples of processes that depend on Na,K-ATPase activity. We hypothesized that 12(R)HETE as an endogenous inhibitor of Na, K-ATPase modulates these processes in the eye and therefore contribute to the maintenance of corneal transparency and IOP. 12(R)DH-HETE, on the other hand, is a powerful pro-inflammatory compound; it dilates blood vessels, increases membrane permeability, stimulates neutrophil migration and produces neovascularization. The effect of 12(R)DH-HETE on the rabbit eye mimic the response of the eye to an inflammatory stimulus. Vasodilatation, breakdown of the blood aqueous barrier and neovascularization are well known consequences of ocular inflammation. We hypothesize that inflammation that typically occurs following injury of the cornea is mediated, in part, by the release of 12(R)DH-HETE produced by the corneal epithelium. These inflammation consequences are events common to many pathological processes in the eye beyond injury to the corneal epithelium. It will be of interest in the future to investigate the involvement of 12(R)DH-HETE in conditions such as uveitis, age-related macular degeneration and diabetic retinopathy. To assess the importance of these novel metabolites in ocular functions, certain questions regarding the biochemistry and the mechanism of action of these compounds have to be addressed. In particular, the questions of the enzymic steps leading to their formation, their metabolic degradation in ocular tissues and whether other ocular tissues have the capacity to produce them have to be answered before an evaluation on their therapeutic potential can be drawn.