Effects of Statins on Heme Oxygenase-1 Regulation

描述（由申请人提供）：抗氧化防御蛋白血红素加氧酶-1（HO-1）近年来已成为组织保护和抗炎作用的重要介质。HO-1的细胞保护功能已在多种组织中被证实，包括脉管系统、心脏、肾脏和神经元细胞。HO-1是一种诱导酶，催化血红素降解，导致胆红素，铁和一氧化碳（CO）的产生，这些都是生物活性产物。胆红素在生理浓度下具有很强的抗氧化作用。CO同样显示出产生抗细胞凋亡和细胞保护作用，此外，作为平滑肌松弛介质发挥作用。组织保护和平滑肌松弛特性的独特组合使HO-1成为治疗妊娠中某些疾病的有趣靶点。研究表明，HO-1对于在怀孕期间保持人体子宫处于放松状态至关重要。此外，胎盘HO-1水平降低似乎与先兆子痫的风险较高有关。因此，旨在适度增加HO-1的组织表达的治疗策略可能有益于许多疾病状态，包括与妊娠和人类发育相关的疾病状态。然而，已知的HO-1诱导剂，如重金属或氧化应激介质，对组织有害，不适用于治疗目的。HMG-CoA还原酶抑制剂，广泛用作降脂药物（他汀类药物），诱导HO-1表达，从而降低氧化应激。因此，他汀类药物或其衍生物在与HO-1表达不足相关的病理条件下可能具有治疗益处。在这个项目中，我们将使用转基因（Tg）小鼠的转基因组成的HO-1启动子融合到荧光素酶报告基因研究他汀类药物依赖的HO-1诱导在体内，特别是，以确定哪些器官和组织响应增加HO-1的表达。此外，我们将确定区域的HO-1启动子调节他汀类药物的反应，通过使用小鼠体内转染HO-1衍生的缺失突变体。他汀类药物的体内效应将通过两种非侵入性测定法进行监测：全身CO排泄，胆红素产生的指标;和生物发光成像（BLI），HO-1转录的指标。来自这些体内测定的数据将与HO-1和HO-2 mRNA和蛋白水平以及总HO酶活性的体外测定相关。这将是第一次共同努力来描述HO-1作为他汀类药物的新治疗靶点和HO-1表达不足条件下（如先兆子痫和其他妊娠相关疾病）保护作用的介导剂的作用

DESCRIPTION (provided by applicant): The antioxidant defense protein heme oxygenase-1 (HO-1) has emerged in recent years as an important mediator of tissue protective and anti-inflammatory actions. Cytoprotective functions of HO-1 have been documented in a variety of tissues including the vasculature, heart, kidney, and neuronal cells. HO-1 is an inducible enzyme that catalyzes the degradation of heme, leading to the generation of bilirubin, iron, and carbon monoxide (CO), which are, in turn, all bioactive products. Bilirubin exerts strong antioxidant effects at physiological concentrations. CO has likewise been shown to produce anti-apoptotic and cytoprotective actions and, in addition, to function as a smooth muscle relaxing mediator. The unique combination of tissue protective and smooth muscle relaxing properties makes HO-1 an interesting target for treatment of certain disorders in pregnancy. It has been shown that HO-1 is crucial for keeping the human uterus in a relaxed state during pregnancy. Moreover, a reduced level of placental HO-1 seems to be associated with a higher risk for pre-eclampsia. Thus, therapeutic strategies aimed at moderately increasing tissue expression of HO-1 might be beneficial in a number of disease states including those related to pregnancy and human development. However, known inducers of HO-1, such as heavy metals or mediators of oxidative stress, are detrimental to tissues and not suitable for therapeutic purposes. HMG-CoA reductase inhibitors, widely used as lipid-lowering drugs (statins), induce HO-1 expression and, as a consequence reduce oxidative stress. Thus, statins or their derivatives might be of therapeutic benefit under pathological conditions associated with insufficient HO-1 expression. In this project, we will use transgenic (Tg) mice where the transgene consists of the HO-1 promoter fused to the luciferase reporter gene to study statin-dependent HO-1 induction in vivo, and, specifically, to determine which organs and tissues respond with increased HO-1 expression. Moreover, we will identify regions in the HO-1 promoter that regulate statin responsiveness by using mice transfected in vivo with HO-1-derived deletion mutants. The in vivo effects of statins will be monitored by two noninvasive assays: total body CO excretion, an index of bilirubin production; and bioluminescence imaging (BLI), an index of HO-1 transcription. Data from these in vivo assays will be correlated with in vitro assays of HO-1 and HO-2 mRNA and protein levels and total HO enzyme activity. This will be the first concerted effort to delineate the role of HO-1 as a novel therapeutic target for statins and mediator of protective effects under conditions of insufficient HO-1 expression such as pre-eclampsia and other pregnancy-related disorders