Investigating the role of PHD3 in lipid homeostasis

项目摘要 细胞代谢的适应对于维持组织和全身的动态平衡至关重要。在……里面 对低能量或应激的响应，细胞激活AMP激活的蛋白激酶(AMPK)使其磷酸化 乙酰辅酶A羧基酶(ACC)，可增加线粒体脂肪酸氧化(FAO)和ATP 级别。然而，在能源丰富的国家，粮农组织是如何被下调监管的，目前还不完全清楚。AS 驱动燃料成瘾的途径可能为个性化治疗提供新的治疗靶点或生物标志物 在治疗方面，迫切需要确定调节代谢稳态的途径。我们有 通过很少的研究发现了一种新的营养依赖的信号通路来控制脂肪氧化 Pro羟基酶结构域蛋白家族的成员，PHD3。博士是-酮戊二酸家族的一员 依赖的双加氧酶，使底物脯氨酸残基羟化，并与燃料相连 正在切换。我们发现PHD3通过羟化乙酰辅酶A羧基酶来调节脂肪酸代谢 (ACC2)，线粒体粮农组织的调节者。作为对营养丰富的反应，PHD3激活ACC2 抑制脂肪酸的分解代谢。由于ACC2和PHD3在氧化组织中高表达 例如骨骼肌，这一提议将检验这样一个假设，即骨骼肌中PHD3的丢失 通过阻止ACC2羟化来解除能量平衡，从而导致结构性 线粒体氧化代谢。该提案将通过以下方式来检验这些想法：1)定义动力学和 确定PHD3介导的羟化调节ACC2的特异性，2)确定作用 PHD3在骨骼肌细胞能量学营养信号中的作用，以及3)测试生理 PHD3与体内肌肉能量动态平衡的相关性。首先，我们将利用重组纯化的 PHD3与HIF1羟基化反应的动力学参数。接下来我们将 通过PhD1-3检测ACC2羟化的特异性(目标1)。我们还将研究以下方面的影响 PHD3对骨骼肌细胞代谢的影响。我们将研究 AMPK、ACC2和HIF1信号对PHD3代谢作用的必要性(目标2)。最后，我们会 研究PHD3活性在静息状态和运动过程中对骨骼肌生理的影响 急性能源挑战(目标3)。我们的首要目标是阐明PHD3的分子成分 控制细胞新陈代谢并利用这些发现最终发展的信号 促进改善肌肉功能和新陈代谢健康的治疗策略。

Project Summary Adaptation of cellular metabolism is crucial for maintaining tissue and whole-body homeostasis. In response to low energy or stress, cells activate AMP-activated protein kinase (AMPK) to phosphorylate acetyl-CoA carboxylase (ACC), which increases mitochondrial fatty acid oxidation (FAO) and ATP levels. However, how FAO is downregulated in energy abundance states is not fully understood. As pathways that drive fuel addiction may provide new therapeutic targets or biomarkers for personalized therapy, there is a critical need to identify pathways that regulate metabolic homeostasis. We have discovered a new nutrient-dependent signaling pathway that controls fat oxidation via a little studied member of the prolyl hydroxylase domain protein family, PHD3. PHDs are a family of -ketoglutarate dependent dioxygenases that hydroxylate substrate proline residues and have been linked to fuel switching. We find that PHD3 regulates fatty acid metabolism by hydroxylating acetyl-CoA carboxylase (ACC2), a regulator of mitochondrial FAO. In response to nutrient abundance, PHD3 activates ACC2 to inhibit catabolism of fatty acids. Since ACC2 and PHD3 are highly expressed in oxidative tissues such as skeletal muscle, this proposal will test the hypothesis that the loss of PHD3 in skeletal muscle deregulates energy homeostasis by preventing ACC2 hydroxylation, hence causing constitutive mitochondrial oxidative metabolism. This proposal will test these ideas by: 1) defining the kinetics and determining the specificity by which PHD3-mediated hydroxylation regulates ACC2, 2) defining the role of PHD3 in nutrient signaling in skeletal muscle cell energetics, and 3) testing the physiological relevance of PHD3 in muscle energy homeostasis in vivo. First, we will utilize recombinant purified PHD3 to quantify the kinetic parameters of PHD3 hydroxylation of ACC2 versus HIF1. Next we will examine the specificity of ACC2 hydroxylation by PHD1-3 (Aim 1). We will also examine the effect of PHD3 on cellular metabolism in skeletal muscle cells in response to nutrient cues. We will examine the necessity of AMPK, ACC2, and HIF1 signaling on the metabolic roles of PHD3 (Aim 2). Finally, we will examine the consequences of PHD3 activity on skeletal muscle physiology in a resting state and during acute energy challenge (Aim 3). Our overarching goal is to elucidate the molecular elements of PHD3 signaling that control cellular metabolism and to leverage these findings to ultimately develop therapeutic strategies to promote improved muscle function and metabolic fitness.