Macrophage GLUD1 is Essential for Redox Balance and Immune Homeostasis in Cardiac Injury

ABSTRACT Excessive free radical production and dysregulated immune responses contribute to myocardial ischemia‐reperfusion (IR) injury. However, the mechanisms by which macrophages regulate reactive oxygen species (ROS) homeostasis and orchestrate immune responses during IR injury remain elusive. Here, we show that glutamate dehydrogenase 1 (GLUD1) expression is induced in monocytes from patients with acute myocardial infarction after interventional therapy and in cardiac‐recruited macrophages from mice subjected to IR injury. GLUD1‐deficient macrophages exacerbate IR injury by increasing mitochondrial ROS accumulation and amplifying pro‐inflammatory responses. Mechanistically, GLUD1 deficiency leads to mitochondrial ROS accumulation due to reduced NADPH/NADP + and GSH/GSSG ratios during IR injury. Elevated mitochondrial ROS inhibits PHD2 activity, stabilizing HIF‐1α and enhancing NF‐κB signaling, promoting the release of pro‐inflammatory factors and exacerbating myocardial damage. Systemic activation of GLUD1 or adoptive transfer of monocytes pre‐treated with a GLUD1 activator preserved cardiac function and mitigated IR injury. These findings highlight macrophage GLUD1 as a critical regulator of redox balance and immune homeostasis, presenting a promising therapeutic target for alleviating IR injury and preserving cardiac function.