Platelet Metabolism in Diabetes Mellitus

项目总结/摘要 心脏病和中风是美国第一和第五大死亡原因。1型糖尿病（T1 DM） 会显著增加心脏病发作和中风的风险据报道，强化血糖控制 降低主要心血管事件> 30%，表明高血糖是导致心血管疾病的主要因素之一。 T1 DM相关心脏病发作和卒中风险增加。然而，T1 DM和高血糖如何加剧 这种风险尚不清楚。血小板是血管的第一反应者，在血管破裂时激活止血 损伤;而致病性血小板活化导致假性血栓形成和急性血管阻塞。 T1 DM和高血糖症导致血小板活性亢进和血栓形成倾向增加。这一提议 目的是了解高血糖如何导致T1 DM患者的血小板过度活跃和血栓形成， 新的治疗策略，以减轻T1 DM相关的心脏病发作和中风。利用综合 代谢工具包，包括最先进的稳定同位素解析代谢组学（SIRM），我们证明了 血小板代谢改变在凝血酶诱导的血小板活化中的关键作用。特别是凝血酶 刺激改变了以糖原代谢、磷酸戊糖途径为中心的血小板代谢 (PPP)和果糖1，6-二磷酸（F1，6 BP），即“糖原-PPP-F1，6 BP轴”，调节能量， 氧化还原和钙稳态的血小板，并导致其活化。文学和我们令人信服的 初步数据进一步揭示，高血糖症增加糖原储存及其动员， ATP，PPP抑制，活性氧和细胞内钙，所有这些都符合增加 血小板活化的倾向。因此，我们的总体假设是，高血糖改变了 血小板中的糖原-PPP-F1，6 BP轴驱动血小板过度活跃，从而导致T1 DM中的血栓形成风险。在目标1中， 我们将描述这些高血糖诱导的血小板糖原-PPP-F1，6 BP轴的变化 来自T1 DM患者和正常健康血小板的体外急性高血糖。在目标2中，我们将 确定通过药理学和遗传学手段调节糖原-PPP-F1，6 BP轴如何抑制 高血糖诱导的体外血小板高活性。在目标3中，我们将确定如何调节糖原- PPP-F1，6 BP轴通过药理学和遗传学手段减少高血糖症加重的血栓形成， 中风动物模型。我们的团队处于一个独特的位置来解决我们的假设，因为我们拥有公认的 代谢和代谢组学（Qingjun Wang PhD和Matthew Gentry PhD），血小板生物学 （Sidney Whiteheart博士）、T1 DM（丽莎坦诺克医学博士）和卒中（Justin Fraser医学博士和Jill Roberts博士），以及 我们与肯塔基州大学代谢组学、氧化还原代谢和啮齿动物研究所建立了强有力的合作伙伴关系。 手术核心。在拟议项目完成后，我们将提出一个新的机制， 血小板代谢失调介导高血糖诱导的血小板过度活化和血栓形成 T1 DM，并将确定新的治疗靶点，以减轻T1 DM相关的心脏病发作和中风。

Project Summary/Abstract Heart disease and stroke are the No. 1 and 5 causes of deaths in the US. Type 1 diabetes mellitus (T1DM) significantly increases the risk for heart attacks and strokes. Intense glycemic control has been reported to reduce major cardiovascular events by >30%, suggesting that hyperglycemia is one of the major contributors to T1DM-associated heart attack and stroke risk escalation. However, how T1DM and hyperglycemia exacerbate such risk is unclear. Platelets are vascular first-responders that activate for hemostasis upon blood vessel damage; whereas pathogenic platelet activation leads to spurious thrombosis and acute vascular obstruction. T1DM and hyperglycemia lead to platelet hyperactivity and increased propensity to form thrombi. This proposals aims to understand how hyperglycemia causes platelet hyperactivity and thrombosis in T1DM, and to develop new therapeutic strategies to mitigate T1DM-associated heart attacks and strokes. Utilizing an integrated metabolism toolkit including state-of-the-art Stable Isotope Resolved Metabolomics (SIRM), we demonstrated critical role of altered platelet metabolism in thrombin-induced platelet activation. Specifically, thrombin stimulation alters platelet metabolism that is centered on glycogen metabolism, pentose phosphate pathway (PPP), and fructose 1,6-bisphosphate (F1,6BP), namely, “the glycogen-PPP-F1,6BP axis”, modulating energy, redox and calcium homeostasis in platelets and leading to their activation. Literature and our compelling preliminary data further reveal that hyperglycemia increases glycogen storage and its mobilization that generates ATP, PPP inhibition, reactive oxygen species, and intracellular calcium, all of which are in line with increased propensity for platelets to activate. Therefore, our overarching hypothesis is that hyperglycemia changes the glycogen-PPP-F1,6BP axis in platelets to drive platelet hyperactivity and thus thrombotic risk in T1DM. In Aim 1, we will delineate these hyperglycemia-induced changes in the glycogen-PPP-F1,6BP axis in platelets isolated from T1DM patients and normal healthy platelets subject to acute hyperglycemia in vitro. In Aim 2, we will determine how modulation of the glycogen-PPP-F1,6BP axis by pharmacological and genetic means suppresses hyperglycemia-induced platelet hyperactivity in vitro. In Aim 3, we will determine how modulation of the glycogen- PPP-F1,6BP axis by pharmacological and genetic means reduces hyperglycemia-exacerbated thrombosis and stroke in animal models. Our team is in a unique position to address our hypothesis, as we possess recognized expertise in metabolism and metabolomics (Qingjun Wang PhD and Matthew Gentry PhD), platelet biology (Sidney Whiteheart PhD), T1DM (Lisa Tannock MD), and stroke (Justin Fraser MD and Jill Roberts PhD), and we have strong partnership with the University of Kentucky Metabolomics, Redox Metabolism, and Rodent Surgery Cores. Upon completion of the proposed project, we will have presented a novel mechanism for metabolic dysregulation in platelets to mediate hyperglycemia-induced platelet hyperactivity and thrombosis in T1DM, and will have identified new therapeutic targets for mitigating T1DM-associated heart attacks and strokes.