NOVEL ROLE OF SPHINGOLIPIDS IN MAINTAINING VASCULAR HOMEOSTASIS

项目概要 为此 K08 应用提出的研究将使用独特的方法来检验 鞘脂代谢对人体脉管系统内血流诱导血管舒张（FID）介质的影响。 最近的研究表明，神经酰胺（一种生物活性鞘脂）在血浆中含量升高 患有心血管疾病的患者，是主要不良心血管事件的独立预测因子。一个 神经酰胺可能对结果产生不利影响的潜在方式是其最近发现的对介质的影响 FID。接触神经酰胺的小动脉会因血流而扩张，产生 H2O2，H2O2 是一种促炎和促炎症物质。 动脉粥样硬化介质，与一氧化氮 (NO) 不同，一氧化氮是抗炎、抗动脉粥样硬化介质 健康成年人为了应对流量增加而使用。相反，1-磷酸鞘氨醇 (S1P) 也 属于鞘脂家族，是神经酰胺的代谢产物，可促进 NO 依赖性 FID。鞘脂如何 影响流动过程中形成的血管活性介质并影响血管稳态仍然很大程度上未知。 该提案的目的是研究鞘脂（也称为“鞘脂变阻器”）的平衡如何 影响特定 FID 介体的产生，这将对形成或产生深远的影响 预防炎症和动脉粥样硬化。总体而言，该应用程序代表了必要的第一步 定义 FID 期间鞘脂代谢在人体微循环中的机制作用。 奖励阶段的培训计划将从四个方面扩展我的科学技能。首先，我会 使用已建立的人体血管反应模型来扩展我的培训和经验，以研究如何 鞘脂代谢和 S1P: 神经酰胺比率决定 FID 的介质。其次，在一个 在王瑞康博士的实验室休假期间，我将接受组织成像方面的培训，特别是体内成像 微血管成像，目标是采用新技术（CytoCam）将我们的发现转化为 整个人类。我还将接受 Andrew Morris 博士的培训，了解如何从小量测量鞘脂 使用液相色谱串联质谱 (LC MS/MS) 分析人体样本。该仪器是 MCW 提供，但尚未适用于鞘脂测量。将这项技术引入 MCW 将极大地加强我的研究计划，并支持其他需要定量小规模脂质介质的人 组织样本。第三，我将完成生物统计学、资助写作、高级质量方面的正式课程 光谱测定技术、临床试验设计和医学成像。这些课程是专门选择的 我和我的指导团队将补充我的正式培训，并将在我继续学习的过程中提供重要的知识 发展成为一名独立调查员。该培训计划的第四个组成部分涉及承担 领导角色，例如担任学生的导师、管理由临床医生和 研究人员，在国家会议上组织研讨会，并在科学咨询委员会任职 美国麻醉学会。其中前三个组件已经在进行中。

Project Summary The studies proposed for this K08 application will use unique approaches to examine the effects of sphingolipid metabolism on the mediator of flow-induced vasodilation (FID) within the human vasculature. Recently it has been shown that ceramide, a bioactive sphingolipid known to be elevated in the plasma of patients with cardiovascular disease, is an independent predictor of major adverse cardiovascular events. A potential way ceramide could adversely affect outcomes is by its recently discovered effect on the mediator of FID. Arterioles exposed to ceramide dilate in response to flow by generating H2O2, a pro-inflammatory and pro- atherosclerotic mediator as opposed to nitric oxide (NO), the anti-inflammatory, anti-atherosclerotic mediator utilized by healthy adults in response to increased flow. On the contrary, sphingosine-1-phosphate (S1P), also within the sphingolipid family and a metabolite of ceramide, promotes NO-dependent FID. How sphingolipids affect vasoactive mediators formed during flow and impact vascular homeostasis remains largely unknown. The aims of this proposal examine how the balance of sphingolipids, also known as the `sphingolipid rheostat,' influences the generation of a specific FID mediator which will have a profound impact on the formation or prevention of inflammation and atherosclerosis. Overall this application represents the necessary first step to define the mechanistic role of sphingolipid metabolism during FID in the human microcirculation. The training plan during the award phase will expand my scientific skill set in four ways. First, I will expand my training and experience using an established human vascular reactivity model to investigate how sphingolipid metabolism and the S1P:ceramide ratio determine the mediator of FID. Second, during a sabbatical in the laboratory of Dr. Ruikang Wang, I will receive training in tissue imaging, specifically in vivo microvascular imaging, with the goal of adapting a new technology (CytoCam) to translate our findings to the whole human. I will also receive training from Dr. Andrew Morris, in how to measure sphingolipids from small human samples using liquid chromatography tandem mass spectrometry (LC MS/MS). This instrumentation is available at MCW but has not been adapted for sphingolipid measurements. Bringing this technology to MCW will greatly strengthen my research program and support others needing to quantify lipid mediators in small tissue samples. Third, I will complete formal coursework in biostatistics, grant writing, advanced mass spectrometry techniques, clinical trial design, and medical imaging. These courses were specifically chosen by me and my mentoring team to supplement my formal training, and will provide vital knowledge as I continue to develop into an independent investigator. The fourth component of this training plan involves taking on leadership roles, such as being a mentor to students, managing an affinity group consisted of clinicians and researchers, organizing symposia at national meetings, and serving on scientific advisory committees for the American Society of Anesthesiology. The first three of these components are already in progress.