Mechanisms of glycine-based therapy for atherosclerosis

动脉粥样硬化引起的心血管疾病(CVD)仍然是主要的死亡原因。当前的脂类- 降低治疗方法不能完全消除心血管疾病风险，可能是因为对其他主要风险缺乏影响。 血脂异常以外的因素。氨基酸代谢异常(AA)在心脏代谢中的报道 2型急性心肌梗死患者以低甘氨酸为共同因子的疾病 糖尿病(T2D)、肥胖和非酒精性脂肪性肝病(NAFLD)。而潜在的机制是 甘氨酸对T2D和NAFLD的保护作用已被确定，甘氨酸在胆固醇代谢和 动脉粥样硬化是未知的。我们最近报道甘氨酸是最有效的降低脂肪堆积的氨基酸。 在巨噬细胞中。在我们的初步研究中，抑制驱动甘氨酸生物合成的关键途径是 在人类和小鼠的动脉粥样硬化条件下很明显。使用我们新开发的AA-去甘氨酸 改进的西方饮食(WD)增加了apoE-/-小鼠的高胆固醇血症和动脉粥样硬化。相比之下， 甘氨酸治疗可以保护这些表型，同时降低高血糖和肝脏脂肪变性， 这些都是其他主要的心血管疾病危险因素。这与较低的脂质过氧化和诱导 推动谷胱甘肽生物合成和胆固醇向胆汁运输的途径。此外，我们还确定了一个 基于甘氨酸的化合物(DT-109)，在小鼠中具有双重降胆固醇和降血糖特性。我们的发现 使我们假设基于甘氨酸的治疗是通过诱导谷胱甘肽介导的动脉粥样硬化保护作用 抗氧化防御和肝肠胆固醇排泄。这项研究的长期目标是 确定动脉粥样硬化中甘氨酸代谢受损，建立以甘氨酸为基础的抗动脉粥样硬化治疗 以减少其他心血管疾病危险因素，并揭示其潜在机制。AIM 1将评估受损人员 甘氨酸在动脉粥样硬化中的合成和增加利用。我们将使用转录组学和代谢组学 在apoE-/-中，我们新的AGXT1-/-小鼠和人类脂肪肝样本。基因驱动的变异之间的联系 甘氨酸代谢和动脉粥样硬化性疾病将由人类GWAS决定。目标2将决定 较低和较高甘氨酸利用率对动脉粥样硬化发展的影响。我们将使用apoE-/-小鼠喂养 WD加或不加甘氨酸或用DT-109治疗。与apoE-/-小鼠杂交的AGXT1-/-小鼠将用于 确定内源性甘氨酸的作用。AIM 3将DT-109确立为一种基于甘氨酸的治疗方法 动脉粥样硬化，其药代动力学和潜在的机制。将使用动脉粥样硬化性载脂蛋白E-/-小鼠 用代谢组学、通量组学和肝肠胆固醇评价甘氨酸对谷胱甘肽的掺入 排泄物。我们将研究DT-109与甘氨酸相比，逆转已建立的动脉粥样硬化的能力。 APOE-/-小鼠。完成这些研究将为基于甘氨酸的动脉粥样硬化新疗法奠定基础。 虽然概述的职业发展计划，包括动手培训、课程作业和研讨会，将使 我的长期目标是成为心脏代谢研究的独立研究员.

Cardiovascular disease (CVD) arising from atherosclerosis remains a leading cause of death. Current lipid- lowering therapies cannot completely eliminate CVD risk, likely due to lack of influence on other major risk factors beyond dyslipidemia. Dysregulated metabolism of amino acids (AA) was reported in cardiometabolic diseases with lower circulating glycine as a common denominator in acute myocardial infarction, type 2 diabetes (T2D), obesity and nonalcoholic fatty liver disease (NAFLD). While potential mechanisms by which glycine protects from T2D and NAFLD have been identified, the role of glycine in cholesterol metabolism and atherosclerosis is unknown. We recently reported glycine as the most potent AA in lowering lipid accumulation in macrophages. In our preliminary studies here, suppression of key pathways driving glycine biosynthesis was evident in atherogenic conditions in humans and mice. Glycine deprivation using our newly developed AA- modified Western diets (WD) enhanced hypercholesterolemia and atherosclerosis in apoE-/- mice. In contrast, glycine treatment was protective of those phenotypes, while lowering hyperglycemia and hepatic steatosis, which are other major CVD risk factors. This was associated with lower lipid peroxidation and induction of pathways driving glutathione biosynthesis and transport of cholesterol into bile. Furthermore, we identified a glycine-based compound (DT-109) with dual cholesterol- and glucose-lowering properties in mice. Our findings led us to hypothesize that glycine-based treatments are atheroprotective by inducing glutathione-mediated antioxidant defense and hepatic-intestinal cholesterol excretion. The long-term objectives of this study are to ascertain impaired glycine metabolism in atherogenesis, establish antiatherogenic glycine-based therapy able to reduce other CVD risk factors and uncover the underlying mechanisms. Aim 1 will assess impaired synthesis and increased utilization of glycine in atherogenesis. We will use transcriptomics and metabolomics in apoE-/-, our new AGXT1-/- mice and human fatty liver samples. The link between variants in genes driving glycine metabolism and atherosclerotic disease will be determined by human GWAS. Aim 2 will determine the effects of lower and higher glycine availability on atherosclerosis development. We will use apoE-/- mice fed WD with or without glycine or treated with DT-109. AGXT1-/- mice crossbred with apoE-/- mice will be used to determine the role endogenous glycine. Aim 3 will establish DT-109 as a glycine-based therapy for atherosclerosis, its pharmacokinetics and the underlying mechanisms. Atherosclerotic apoE-/- mice will be used to assess glycine incorporation to glutathione by metabolomics and fluxomics and hepatic-intestinal cholesterol excretion. We will study the ability of DT-109, compared to glycine, to regress established atherosclerosis in apoE-/- mice. Completing these studies will set the basis for novel glycine-based treatments for atherosclerosis, while the outlined career development plan, including hands-on training, coursework and seminars, will allow me to develop my long-term goal of becoming an independent investigator in cardiometabolic research.