Synergistic effects of CAR-modified mesenchymal stem cells and MGST1 activation in facilitating myocardial tissue repair post-ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury remains a major clinical challenge that undermines the benefits of reperfusion therapy and contributes to adverse cardiac remodeling. Despite their regenerative potential, the therapeutic efficacy of mesenchymal stem cells (MSCs) is limited by poor engraftment and low survival under ischemic conditions. To address these limitations, we developed a combinatorial strategy utilizing low-density lipoprotein receptor-related protein 6 (LRP6)-targeted chimeric antigen receptor-engineered MSCs (CAR-MSCs) to enhance site-specific homing to injured myocardium, coupled with overexpression of microsomal glutathione S-transferase 1 (MGST1) to strengthen cellular antioxidant defense. We evaluated this approach in both cellular and animal models of I/R injury. In vitro, under oxygen–glucose deprivation/reoxygenation (OGD/R) conditions, treatment with MSCs, CAR-MSCs, or MGST1 overexpression alone each attenuated OGD/R-induced injury. The combination of unmodified MSCs with MGST1 overexpression (MSCs + MGST1) further improved cell viability and reduced apoptosis compared to MSCs alone. Notably, the combination of CAR-MSCs and MGST1 overexpression (CAR-MSCs + MGST1) exhibited the most pronounced protective effects, significantly outperforming all other groups, including MSCs + MGST1, in enhancing cell viability, reducing apoptosis and intracellular reactive oxygen species (ROS) levels, modulating oxidative stress markers (MDA, SOD, CAT), and promoting the secretion of reparative growth factors (VEGF, IGF-1, HGF). In a rat I/R model, combined treatment significantly reduced infarct size, ameliorated histological damage, decreased collagen deposition and apoptosis, and consistently modulated serum oxidative and regenerative biomarkers. Mechanistically, the combined intervention activated the Nrf2/Keap1 signaling pathway, upregulating downstream effectors NQO1 and HO-1. The cardioprotective effects were partially abolished by Nrf2 inhibition. In summary, LRP6-targeted CAR-MSCs coupled with MGST1 overexpression deliver synergistic protection against I/R injury by activating the Nrf2/Keap1 antioxidant program, offering a clinically translatable strategy to enhance precision MSC therapy and mitigate reperfusion-driven cardiac damage.