Role of lactate dehydrogenase A in endothelial metabolism and angiogenesis

血管系统是一个广泛的网络，为组织提供氧气、营养物质和各种 血管分泌因子。它主要是通过血管生成形成的，在这个过程中新的血管从 现存的血管系统。血管生成对胚胎发育、组织生长和再生至关重要， 它还参与了许多人类疾病的发病机制。例如，增殖性糖尿病视网膜病变 早产儿视网膜病变(PDR)和早产儿视网膜病变(ROP)是可能导致糖尿病患者视力丧失的眼部疾病 和早产儿。这两种眼病的特征都是视网膜过度。 血管生成，导致玻璃体内出血、黄斑水肿，甚至视网膜脱离。然而， 目前抑制PDR和ROP异常血管形成的治疗策略效果有限 并可能引起不良的副作用。因此，了解驱动血管的机制 形成是重要的，因为它可以促进更好的治疗这些严重的眼睛的方法的发展。 疾病。通过血管生成形成的新血管包括增殖、迁移和几个 其他耗能的内皮细胞(EC)行为。最近的研究表明，增殖的内皮细胞 优先将葡萄糖转化为乳酸，并通过糖酵解而不是葡萄糖产生~85%的ATP 通过TCA循环进行氧化，即使ECs生长在富氧环境中也是如此。这种新陈代谢特征 也出现在癌细胞中，被称为华宝效应。然而，在分子水平上仍不清楚。 为什么乳酸盐而不是TCA循环中的代谢物在增殖的内皮细胞中从葡萄糖中有利地产生。 申请人实验室的初步研究表明，乳酸脱氢酶A(LDHA)是一种催化 丙酮酸转化为乳酸和从NADH再生NAD+，是潜在的关键驱动因素 欧洲共同体中的华宝效应。这一应用的中心假设是LDHA控制着 通过调节内皮细胞中的糖酵解通量来维持血管生成。我们将通过两个例子来检验这一假设 明确的目标。AIM 1将使用各种代谢分析和内皮特异性LDHA基因敲除小鼠来确定 低密度脂蛋白在调节WARBURG效应及发育和病理血管生成中的作用 视网膜。通过结合小鼠遗传模型、分子和生化方法以及高级分析 工具，AIM 2将确定控制内皮细胞LDHA表达的上游调控因子，并将阐明 LDHA调节内皮生长的机制。总体而言，我们的建议将推动 了解内皮代谢和血管形成之间的联系，它将提供具体的 开发抑制人类眼部疾病血管生成的新策略的步骤。

The blood vascular system is an extensive network that provides tissues with oxygen, nutrients, and a variety of angiocrine factors. It is formed mainly through angiogenesis, a process in which new blood vessels grow from the existing vasculature. Angiogenesis is vital for embryonic development, tissue growth, and regeneration, and is also involved in the pathogenesis of many human diseases. For example, proliferative diabetic retinopathy (PDR) and retinopathy of prematurity (ROP) are eye disorders that may lead to vision loss in diabetic patients and premature babies respectively. Both of these ocular diseases are characterized by excessive retinal angiogenesis, which causes intravitreal hemorrhage, macular edema, and even retinal detachment. However, current treatment strategies to inhibit aberrant blood vessel formation in PDR and ROP only have limited efficacy and may elicit undesirable side effects. Therefore, understanding the mechanisms that drive blood vessel formation is important because it may facilitate the development of better therapies for treating these severe eye diseases. Formation of new blood vessels through angiogenesis involves proliferation, migration, and several other energy-consuming endothelial cell (EC) behaviors. Recent studies have shown that proliferating ECs preferentially convert glucose to lactate and generate ~85% of ATP through glycolysis rather than glucose oxidation via the TCA cycle, even when the ECs are grown in an oxygen-rich environment. This metabolic feature is also seen in cancer cells and is termed the Warburg effect. However, it remains unclear at the molecular level why lactate instead of metabolites in the TCA cycle are favorably produced from glucose in proliferating ECs. Pilot studies from the applicant’s lab suggest that lactate dehydrogenase A (LDHA), an enzyme catalyzing the conversion of pyruvate to lactate and the regeneration of NAD+ from NADH, is a potentially key driver of the Warburg effect in ECs. The central hypothesis of this application is that LDHA controls the metabolic fate of glucose and sustains angiogenesis by regulating glycolytic flux in ECs. We will test this hypothesis through two Specific Aims. Aim 1 will use various metabolic assays and endothelial-specific Ldha knockout mice to determine the roles of LDHA in regulating the Warburg effect and developmental and pathological angiogenesis in the retina. By combining mouse genetic models, molecular and biochemical approaches, and advanced analytical tools, Aim 2 will identify the upstream regulator that controls LDHA expression in ECs and will elucidate the mechanism by which LDHA regulates endothelial growth. Collectively, our proposal will advance the understanding of the link between endothelial metabolism and blood vessel formation, and it will provide concrete steps towards developing new strategies for inhibiting angiogenesis in human ocular diseases.