State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, 1838 Northern Guangzhou Ave, Guangzhou, Guangdong, 510515, China.
Key Laboratory for Organ Failure Research, Ministry of Education of the People's Republic of China, 1838 Northern Guangzhou Ave, Guangzhou, Guangdong, 510515, China.
Mol Med. 2024 Jan 22;30(1):15. doi: 10.1186/s10020-024-00783-1.
In heart failure (HF), mitochondrial dysfunction and metabolic remodeling lead to a reduction in energy productivity and aggravate cardiomyocyte injury. Supplementation with α-ketoglutarate (AKG) alleviated myocardial hypertrophy and fibrosis in mice with HF and improved cardiac insufficiency. However, the myocardial protective mechanism of AKG remains unclear. We verified the hypothesis that AKG improves mitochondrial function by upregulating NAD levels and activating silent information regulator 2 homolog 1 (SIRT1) in cardiomyocytes.
In vivo, 2% AKG was added to the drinking water of mice undergoing transverse aortic constriction (TAC) surgery. Echocardiography and biopsy were performed to evaluate cardiac function and pathological changes. Myocardial metabolomics was analyzed by liquid chromatography‒mass spectrometry (LC‒MS/MS) at 8 weeks after surgery. In vitro, the expression of SIRT1 or PINK1 proteins was inhibited by selective inhibitors and siRNA in cardiomyocytes stimulated with angiotensin II (AngII) and AKG. NAD levels were detected using an NAD test kit. Mitophagy and ferroptosis levels were evaluated by Western blotting, qPCR, JC-1 staining and lipid peroxidation analysis.
AKG supplementation after TAC surgery could alleviate myocardial hypertrophy and fibrosis and improve cardiac function in mice. Metabolites of the malate-aspartate shuttle (MAS) were increased, but the TCA cycle and fatty acid metabolism pathway could be inhibited in the myocardium of TAC mice after AKG supplementation. Decreased NAD levels and SIRT1 protein expression were observed in heart of mice and AngII-treated cardiomyocytes. After AKG treatment, these changes were reversed, and increased mitophagy, inhibited ferroptosis, and alleviated damage in cardiomyocytes were observed. When the expression of SIRT1 was inhibited by a selective inhibitor and siRNA, the protective effect of AKG was suppressed.
Supplementation with AKG can improve myocardial hypertrophy, fibrosis and chronic cardiac insufficiency caused by pressure overload. By increasing the level of NAD, the SIRT-PINK1 and SIRT1-GPX4 signaling pathways are activated to promote mitophagy and inhibit ferroptosis in cardiomyocytes, which ultimately alleviates cardiomyocyte damage.
在心力衰竭（HF）中，线粒体功能障碍和代谢重塑导致能量产生减少，并加重心肌细胞损伤。补充α-酮戊二酸（AKG）可减轻 HF 小鼠的心肌肥大和纤维化，并改善心功能不全。然而，AKG 的心肌保护机制尚不清楚。我们验证了 AKG 通过上调 NAD 水平并激活心肌细胞中的沉默信息调节因子 2 同源物 1（SIRT1）来改善线粒体功能的假说。
在体内，将 2%的 AKG 添加到接受横主动脉缩窄（TAC）手术的小鼠饮用水中。手术后 8 周通过超声心动图和活检评估心功能和病理变化。通过液相色谱-质谱联用（LC-MS/MS）分析心肌代谢组学。在体外，用血管紧张素 II（AngII）和 AKG 刺激的心肌细胞中用选择性抑制剂和 siRNA 抑制 SIRT1 或 PINK1 蛋白的表达。用 NAD 测试试剂盒检测 NAD 水平。通过 Western blot、qPCR、JC-1 染色和脂质过氧化分析评估自噬和铁死亡水平。
TAC 手术后补充 AKG 可减轻 TAC 小鼠的心肌肥大、纤维化和改善心功能。MAS 的代谢物增加，但 TAC 小鼠心肌中 AKG 补充后 TCA 循环和脂肪酸代谢途径受到抑制。在 TAC 小鼠心脏和 AngII 处理的心肌细胞中观察到 NAD 水平和 SIRT1 蛋白表达降低。AKG 处理后，这些变化得到逆转，并观察到心肌细胞中自噬增加、铁死亡抑制和损伤减轻。当 SIRT1 的表达被选择性抑制剂和 siRNA 抑制时，AKG 的保护作用被抑制。
补充 AKG 可改善压力超负荷引起的心肌肥大、纤维化和慢性心功能不全。通过增加 NAD 水平，激活 SIRT-PINK1 和 SIRT1-GPX4 信号通路，促进心肌细胞自噬并抑制铁死亡，最终减轻心肌细胞损伤。
