Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cardiovascular Medicine, The Second Xiangya Hospital, Central South University, Changsha 410000, China.
Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48109, USA.
Cell Rep. 2021 Jul 27;36(4):109420. doi: 10.1016/j.celrep.2021.109420.
Dysregulated glycine metabolism is emerging as a common denominator in cardiometabolic diseases, but its contribution to atherosclerosis remains unclear. In this study, we demonstrate impaired glycine-oxalate metabolism through alanine-glyoxylate aminotransferase (AGXT) in atherosclerosis. As found in patients with atherosclerosis, the glycine/oxalate ratio is decreased in atherosclerotic mice concomitant with suppression of AGXT. Agxt deletion in apolipoprotein E-deficient (Apoe) mice decreases the glycine/oxalate ratio and increases atherosclerosis with induction of hepatic pro-atherogenic pathways, predominantly cytokine/chemokine signaling and dysregulated redox homeostasis. Consistently, circulating and aortic C-C motif chemokine ligand 5 (CCL5) and superoxide in lesional macrophages are increased. Similar findings are observed following dietary oxalate overload in Apoe mice. In macrophages, oxalate induces mitochondrial dysfunction and superoxide accumulation, leading to increased CCL5. Conversely, AGXT overexpression in Apoe mice increases the glycine/oxalate ratio and decreases aortic superoxide, CCL5, and atherosclerosis. Our findings uncover dysregulated oxalate metabolism via suppressed AGXT as a driver and therapeutic target in atherosclerosis.
甘氨酸代谢失调在代谢性心血管疾病中越来越受到关注,但它在动脉粥样硬化中的作用仍不清楚。在这项研究中,我们通过丙氨酸-乙醛酸氨基转移酶(AGXT)证实了动脉粥样硬化中的甘氨酸-草酸代谢失调。与动脉粥样硬化患者一样,在动脉粥样硬化小鼠中,甘氨酸/草酸的比值降低,同时 AGXT 受到抑制。载脂蛋白 E 缺陷(Apoe)小鼠中的 Agxt 缺失会降低甘氨酸/草酸的比值,并通过诱导肝脏前动脉粥样硬化途径增加动脉粥样硬化,主要是细胞因子/趋化因子信号和氧化还原平衡失调。一致地,循环和主动脉 C-C 基序趋化因子配体 5(CCL5)和病变巨噬细胞中的超氧化物增加。在 Apoe 小鼠的饮食草酸过载后也观察到类似的发现。在巨噬细胞中,草酸诱导线粒体功能障碍和超氧化物积累,导致 CCL5 增加。相反,在 Apoe 小鼠中过表达 AGXT 会增加甘氨酸/草酸的比值,并减少主动脉超氧化物、CCL5 和动脉粥样硬化。我们的发现揭示了通过抑制 AGXT 导致的草酸代谢失调是动脉粥样硬化的驱动因素和治疗靶点。