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、营养物质和多种生物活性物质。 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，新血管从 现有的脉管系统。血管生成对于胚胎发育、组织生长和再生至关重要， 也参与许多人类疾病的发病机制。例如，增殖性糖尿病视网膜病变 (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。这两种眼部疾病的特征是过度的视网膜病变。 血管生成，其导致玻璃体内出血、黄斑水肿，甚至视网膜脱离。然而，在这方面， 目前抑制PDR和ROP中异常血管形成的治疗策略仅具有有限的功效 并且可能引起不希望的副作用。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方法的发展，用于治疗这些严重的眼睛 疾病通过血管生成的新血管的形成涉及增殖、迁移和几种生物学行为。 其他消耗能量的内皮细胞（EC）行为。最近的研究表明，增殖的EC 优先将葡萄糖转化为乳酸，通过糖酵解而不是葡萄糖产生约85%的ATP 通过TCA循环的氧化，即使当EC在富氧环境中生长时。这种代谢特征 也见于癌细胞中，称为瓦尔堡效应。然而，在分子水平上仍不清楚 为什么在TCA循环中，乳酸盐而不是代谢物在增殖的EC中有利地从葡萄糖产生。 申请人实验室的初步研究表明，乳酸脱氢酶A（LDHA），一种催化乳酸脱氢酶的酶， 丙酮酸向乳酸的转化和NAD+从NADH的再生，是一个潜在的关键驱动因素。 EC中的瓦尔堡效应。本申请的中心假设是LDHA控制了代谢物的代谢命运。 葡萄糖，并通过调节EC中的糖酵解通量来维持血管生成。我们将通过两个测试来验证这个假设。 具体目标。目的1将使用各种代谢测定和内皮特异性Ldha敲除小鼠来确定 LDHA在调节瓦尔堡效应以及发育和病理性血管生成中的作用。 视网膜。通过结合小鼠遗传模型，分子和生物化学方法，以及先进的分析方法， 工具，目标2将确定控制内皮细胞中LDHA表达的上游调节因子，并将阐明 LDHA调节内皮生长的机制。总的来说，我们的提案将推动 了解内皮代谢和血管形成之间的联系，它将提供具体的 为开发抑制人类眼部疾病血管生成的新策略迈出了重要的一步。

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.