Metabolic Reprogramming in Acute Kidney Injury

描述（由申请人提供）：缺血再灌注损伤（IRI）导致的急性肾损伤（阿基）是一种常见的临床问题，与重症监护环境中的高死亡率相关。此外，它是慢性肾脏病（CKD）进展的重要因素。脯氨酰羟化酶（prolyl-hydroxylase，PHD）/缺氧诱导因子（hypoxia-inducible factor，HIF）氧敏感通路是肾脏缺氧/缺血反应调控的重要途径。PHD蛋白是铁和2-酮戊二酸依赖性加氧酶，其作为氧传感器起作用，并通过催化其α亚基的氧依赖性降解结构域内的特定脯氨酸残基的羟基化来调节HIF活性。HIF是多效异二聚体转录因子，在缺氧/缺血条件下的细胞适应和存活中发挥关键作用。所有三种主要的HIF-PHD，PHD 1、PHD 2和PHD 3，都在肾脏中表达。虽然PHD 2调节肾上皮细胞中的HIF-1活性，并已显示控制肾间质细胞中的促红细胞生成素产生，但PHD 1和PHD 3在肾缺氧反应和病理生理学中的作用尚不清楚。我们的实验室和其他小组已经在临床前动物模型中证明，肾PHD的短期药理学灭活对于预防急性缺血性损伤及其长期后遗症具有巨大的治疗潜力。 为了了解单个PHD在肾脏生理学中的功能作用，并深入了解PHD/HIF介导的肾保护作用的分子和细胞基础，我们已经开始使用遗传学和药理学方法来解剖细胞类型特异性PHD功能及其在肾脏代谢调节中的作用。在此，我们假设PHD/HIF控制的肾上皮细胞代谢重编程在确定缺血性肾损伤的生物学结果中起着核心作用。在这项资助下，我们使用基因工程小鼠来研究肾脏中急性PHD失活的代谢后果。提出了三个具体目标。目的1研究PHD 2在肾脏能量代谢中的作用，目的2研究肾小管上皮PHD 1和PHD 3在肾脏生理学和IRI中的功能作用，目的3研究与IRI中的细胞保护相关的特定代谢途径。

DESCRIPTION (provided by applicant): Acute kidney injury (AKI) resulting from ischemia-reperfusion injury (IRI) is a frequently encountered clinical problem and associates with high mortality in a critical care setting. It is furthermore an important contributor to the progressionof chronic kidney disease (CKD). A central pathway in the regulation of renal hypoxia/ischemia responses is the prolyl-hydroxylase (PHD)/hypoxia-inducible factor (HIF) oxygen-sensing pathway. PHD proteins are iron- and 2-oxoglutarate-dependent oxygenases that function as oxygen sensors and regulate HIF activity by catalyzing the hydroxylation of specific proline residues within the oxygen-dependent degradation domain of it's alpha-subunit. HIFs are pleiotropic heterodimeric transcription factors that play key roles in cellular adaptation and survival under hypoxic/ischemic conditions. All three main HIF-PHDs, PHD1, -2 and -3, are expressed in the kidney. While PHD2 regulates HIF-1 activity in renal epithelial cells and has been shown to control erythropoietin production in renal interstitial cells, the role of PHD1 and PHD3 in renal hypoxia responses and pathophysiology is unknown. Our laboratory and other groups have demonstrated in preclinical animal models that short-term pharmacologic inactivation of renal PHDs has great therapeutic potential for the prevention of acute ischemic injuries and their long-term sequelae. In order to understand the functional role of individual PHDs in renal physiology and to gain insight into the molecular and cellular basis of PHD/HIF-mediated renoprotection, we have begun to use genetic and pharmacologic approaches to dissect cell type-specific PHD functions and their role in the regulation of renal metabolism. Here we hypothesize that PHD/HIF-controlled re-programming of metabolism in renal epithelial cells plays a central role in determining the biological outcome of ischemic kidney injuries. Under this grant we use genetically engineered mice to investigate the metabolic consequences of acute PHD inactivation in the kidney. Three specific aims are proposed. Aims 1 investigates the role of PHD2 in renal energy metabolism, aim 2 examines the functional role of tubular epithelial PHD1 and PHD3 in renal physiology and IRI, and aim 3 examines specific metabolic pathways that associate with cytoprotection in IRI.