Malondialdehyde-induced Endothelial Dysfunction in Atherosclerosis

项目摘要/摘要 丙二醛(MDA)是一种普遍存在的高活性的非酶类脂质过氧化的最终产物， 这是动脉粥样硬化形成过程中的中心事件。丙二醛可以共价修饰蛋白质，被认为是有利的。 炎症和致动脉粥样硬化。提示血中丙二醛水平与冠心病的发生密切相关。 然而，它在动脉粥样硬化形成中的确切作用尚不清楚，因为在体内还没有针对特定的Neu-2的策略。 把它变得陈旧。我们最近建立了IK17-scFv转基因小鼠，表达单链可变片段 针对丙二醛的人IK17抗体(ScFv)。我的初步研究发现IK17-scFv可以改善 西方饮食(WD)诱导的LDLR-/-小鼠动脉粥样硬化。损伤切片的丙二醛染色显示 丙二醛在血管内膜中含量较高，提示内皮细胞是丙二醛的主要靶点。我建议的种马- IES将揭示中和丙二醛减少动脉粥样硬化的机制，重点是 欧共体生物学。作为血管的最内层，正常的内皮细胞对血管的动态平衡和 功能。在生理条件下，完整的内皮细胞在血管完整性和 通透性强，具有抗炎功能，维持正常的血管代谢。我的初选 研究发现，丙二醛在体内可诱导内皮细胞中血红素的过度蓄积，这与诱导血管紧张素转换酶的活性有关。 编码血红素合成酶基因在EC中的表达。与其对氧的正常功能不同 运输和储存，电子转移或药物代谢，过量的血红素会引起炎症和EC障碍- 功能，并增加血管通透性。根据我的初步数据，我假设丙二醛导致 血红素堆积，在动脉粥样硬化形成过程中促进内皮功能障碍。我的建议将作为- 探讨动脉粥样硬化过程中丙二醛-血红素轴对内皮细胞功能障碍的病理影响。在特定Aim1 (K99期)，我将使用IK17-scFvLdlr-/-小鼠剖析丙二醛在EC功能障碍和动脉粥样硬化中的作用。我 还将系统地表征丙二醛对EC转录组的影响。在特定的AIM2(R00阶段)中，i 将表征丙二醛对内皮细胞血红素合成的影响，并阐明其潜在机制。 在特定的Aim3(K99和R00期)，我将产生一种新的可诱导内皮细胞特异性的Alas1 (血红素合成限速酶)基因敲除小鼠模型研究过量的血红素对内切酶的影响 内皮功能障碍和动脉粥样硬化。丙二醛-血红素轴在EC功能障碍中的作用将在体外确定 在活体内。这些研究将揭示靶向丙二醛和血红素可以预防EC-Dys-Dy的机制。 并确定新的治疗策略以改善内皮功能和动脉粥样硬化形成。外面的- 加州大学圣地亚哥分校的常备资源和激励的研究环境将为AP- Plicant的目标是成为一名成功和独立的调查员，候选人的导师有一个成功的- 成功的实习生过渡到独立教员的记录。这项K99/R00奖项将支持AP- 对终身教职的渴望。

PROJECT SUMMARY/ABSTRACT Malondialdehyde (MDA) is a ubiquitous and highly reactive end product of non-enzymatic lipid peroxidation, which is a central event in atherogenesis. MDA can covalently modify proteins, and is thought to be pro- inflammatory and atherogenic. It was shown that blood MDA level is correlated to coronary heart disease. However, its exact roles in atherogenesis are unknown as there were no in vivo strategies to specifically neu- tralize it. We recently generated IK17-scFv transgenic mice, which express a single chain variable fragment (scFv) of the human IK17 antibody that targets MDA. My preliminary studies found that IK17-scFv ameliorated Western diet (WD)-induced atherosclerosis in Ldlr-/- mice. MDA staining of lesion cross-sections showed that MDA is enriched in the intima, indicating endothelial cells (ECs) as a major target of MDA. My proposed stud- ies will uncover the mechanisms by which neutralizing MDA decreases atherosclerosis, with an emphasis on EC biology. As the innermost lining of blood vessels, normal ECs are critical for vascular homeostasis and functions. Under physiological conditions, intact ECs maintain an optimal balance between vessel integrity and permeability, exhibit anti-inflammatory function, and maintain normal vascular metabolism. My preliminary studies found that MDA induced excess heme accumulation in EC in vivo, and this was associated with induc- tion in EC of expression of genes encoding heme synthesis enzymes. Unlike its normal functions for oxygen transport and storage, electron transfer or drug metabolism, excess heme causes inflammation and EC dys- function, and increases vascular permeability. Based on my preliminary data, I hypothesize that MDA induces heme accumulation, which promotes endothelial dysfunction during atherogenesis. My proposal will as- sess the pathological effects of the MDA-heme axis on EC dysfunction during atherosclerosis. In Specific Aim1 (K99 phase), I will dissect roles of MDA in EC dysfunction and atherosclerosis using the IK17-scFvLdlr-/- mice. I will also systematically characterize the effects of MDA on EC transcriptome. In Specific Aim2 (R00 phase), I will characterize the effects of MDA on endothelial heme synthesis, and elucidate the underlying mechanisms. In specific Specific Aim3 (K99 and R00 phase), I will generate a new inducible endothelial cell-specific Alas1 (rate-limiting enzyme for heme synthesis) knockout mouse model to study the impact of excess heme on endo- thelial dysfunction and atherosclerosis. The roles of MDA-heme axis in EC dysfunction will be defined in vitro and in vivo. These studies will uncover mechanisms by which targeting MDA and heme can prevent EC dys- function and define novel therapeutic strategies to improve endothelial function and atherogenesis. The out- standing resources and stimulating research environment at UCSD will provide exemplary support for the ap- plicant’s goal of becoming a successful and independent investigator, and the candidate’s mentor has a suc- cessful track record of transitioning trainees into independent faculty. This K99/R00 award will support the ap- plicant toward a tenure track faculty position.