Myocyte enhancer factor 2a orchestrates vascular redox homeostasis via direct transcriptional activation of SIRT1

Myocyte enhancer factor 2A (MEF2A), a transcription factor implicated in coronary artery disease, remains unexplored in vascular redox regulation. To address this gap and overcome the limitations of current antioxidant therapies, we investigate the role of MEF2A in oxidative defense via human umbilical vein endothelial cells (HUVECs) and murine models. Adenoviral vectors encoding MEF2A-specific shRNAs or mRNAs are used to silence or overexpress <i>MEF2A</i> in HUVECs. For <i>in vivo</i> validation, endothelial-targeted <i>MEF2A</i> knockdown is achieved via AAV1-shRNA delivery in mice fed with a high-fat diet. Systemic redox status is assessed by measuring reactive oxygen species (ROS), glutathione homeostasis (GSH/GSSG ratio), the NADH/NAD ⁺ balance, the mitochondrial membrane potential (ΔΨm), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Mechanistic insights are derived from immunofluorescence, qPCR, western blotting, and dual-luciferase reporter assays. <i>MEF2A</i> silencing induces redox imbalance, characterized by elevated ROS, a reduced GSH/GSSG ratio, and ΔΨm collapse. Conversely, MEF2A overexpression synergizes with SIRT1 to restore the glutathione pool, maintain NAD ⁺ homeostasis, and suppress ROS under oxidative stress. Chromatin immunoprecipitation confirms that MEF2A directly binds to two cis-elements in the <i>SIRT1</i> promoter, driving transcriptional activation. <i>In vivo</i>, MEF2A-deficient mice present increased vascular oxidative damage, as indicated by elevated DNA damage marker (8-OHdG) and ROS levels. The downregulation of SIRT1/PGC-1α in <i>MEF2A</i>-silenced cells is verified <i>in vivo</i>. Our findings establish MEF2A as a master regulator of endothelial redox defense via the SIRT1-PGC-1α axis, providing a mechanistic foundation for the treatment of oxidative cardiovascular disorders. This work suggests that pharmacological MEF2A activation is a novel strategy for precision antioxidant therapy in vascular medicine.