Metabolic Rewiring of the Heart Through Reductive Carboxylation

摘要 术语“癌症和心脏”传统上指的是化疗药物对心脏的毒性作用。 然而，与任何细胞抑制治疗无关，癌症幸存者发生癌症的风险是对照组的五倍。 心力衰竭。因此，新的治疗策略必须考虑肿瘤生物学，以保护 心。例如，已经观察到在异柠檬酸脱氢酶(IDH)1和2突变的肿瘤中， 肿瘤代谢物D-2-羟基戊二酸(D2-HG)的生成增加与全身效应有关， 包括扩张型心肌病。约20%的急性髓系白血病患者存在IDH突变。 这些突变会导致患者存活率显著降低，并导致代谢功能障碍 与高水平的肿瘤代谢物D2-HG有关。然而，D2-HG在多大程度上可以直接 损害心脏功能和新陈代谢，以及参与了哪些过程，目前仍不清楚。最近我 发现D2-HG通过抑制α-酮戊二酸脱氢酶介导心功能不全，从而导致 重定向Krebs循环中间产物，增加ATP柠檬酸裂解酶活性，增加组蛋白3泛- 乙酰化。此外，长期服用D2-HG会导致心脏和骨骼肌萎缩，提示 IDH突变也会刺激结构重塑。我现在建议抑制α-KG 肿瘤代谢物D2-HG的脱氢酶诱导心脏α-KG的还原羧化 导致病理性结构重塑。我的目标是确定肿瘤新陈代谢在 心力衰竭的发病机制。在K99阶段，特定目标1将定义还原羧化的作用 以肿瘤代谢物D2-HG为模型，作为心脏代谢重塑的介体。特定的 目标2将确定还原柠檬酸代谢在能量底物代谢和能量代谢之间的作用 赖氨酸乙酰化的表观遗传重塑。这些实验将过渡到R00阶段，在该阶段 具体目标3将扩展这些发现，以解决支链氨基酸代谢和 D2-HG代谢失控状态下蛋白质组重构的自噬。总体而言，这个项目 将提出一种假说，即肿瘤代谢应激导致心力衰竭的发生。这些新见解 最终改变癌症和心力衰竭患者的治疗方式。

Summary The term “cancer and the heart” traditionally refers to the cardiotoxic effects of chemotherapeutic agents. However, independent of any cytostatic treatment, cancer survivors have a five-fold higher risk for developing heart failure. Therefore, new therapeutic strategies must consider tumor biology when aiming at protecting the heart. For example, it has been observed that in isocitrate dehydrogenase (IDH) 1 and 2 mutant tumors, the elevated production of the oncometabolite D-2-hydroxyglutarate (D2-HG) is associated with systemic effects, including dilated cardiomyopathy. About 20% of acute myeloid leukemia cases harbor mutations of the IDH. These mutations lead to significantly reduced patient survival and cause metabolic dysfunction which are associated with high levels of the oncometabolite D2-HG. However, the extent to which D2-HG can directly impair cardiac function and metabolism, and which processes are involved, is still unknown. Recently I discovered that D2-HG mediates cardiac dysfunction by inhibiting α-ketoglutarate dehydrogenase, which leads to redirection of Krebs cycle intermediates, increased ATP citrate lyase activity, and increased histone 3 pan- acetylation. Furthermore, chronic treatment with D2-HG causes heart and skeletal muscle atrophy, suggesting that IDH mutation also stimulates structural remodeling. I now propose that inhibition of α-KG dehydrogenase by the oncometabolite D2-HG induces reductive carboxylation of α-KG in the heart resulting in pathologic structural remodeling. My goal is to determine the role of oncometabolism in the pathogenesis of heart failure. In the K99 phase, Specific Aim 1 will define the role of reductive carboxylation as a mediator for metabolic remodeling of the heart using the oncometabolite D2-HG as a model. Specific Aim 2 will define the role of reductive citrate metabolism as a link between energy substrate metabolism and epigenetic remodeling by lysine acetylation. These experiments will transition into the R00 phase, which in Specific Aim 3 will extend the findings to address the impact of branched chain amino acid metabolism and autophagy on proteomic remodeling in the metabolically deregulated state of D2-HG. Collectively, this project will advance the hypothesis that oncometabolic stress drives development of heart failure. These new insights ultimately change the way cancer and heart failure patients are treated.