PLD3-mediated Mitophagy Attenuates Neuronal Ferroptosis and Promotes Functional Recovery after Spinal Cord Injury.

Ferroptosis is an important form of cell death following spinal cord injury (SCI), primarily caused by secondary microenvironmental alterations such as oxidative stress induced by local ischemia and hypoxia. Although Phospholipase D3 (PLD3) is known to contribute to neural homeostasis, its function in SCI and the associated mechanisms remain largely undefined. This study explores the role of PLD3 in the pathological process following SCI. In a mouse SCI model, proteomic analysis and biochemical assays revealed a marked reduction of PLD3 expression in injured spinal cord tissue, accompanied by elevated oxidative stress and ferroptosis markers. Adeno-associated virus-mediated overexpression of neuronal PLD3 significantly promoted spinal cord tissue repair and improved in vivo neurological function recovery. In an oxygen and glucose deprivation (OGD) model established using PC12 cells, PLD3 expression was significantly reduced, accompanied by mitochondrial dysfunction and increased oxidative stress and changes related to ferroptosis. PLD3 overexpression alleviated mitochondrial dysfunction, oxidative stress, and injury associated with ferroptosis in OGD-treated PC12 cells. Mechanistically, PLD3 overexpression was associated with activation of the PINK1/Parkin pathway, enhanced mitochondrial quality control responses related to mitophagy, and preservation of mitochondrial homeostasis. Complementary pharmacological experiments using Mdivi-1 and Cyclosporine A further supported an association between the protective effects of PLD3 overexpression, mitochondrial quality control, and injury related to ferroptosis. Collectively, these findings suggest that PLD3 overexpression helps maintain mitochondrial function and homeostasis in OGD-treated PC12 cells through mechanisms associated with PINK1/Parkin-related mitophagy. Together with the in vivo findings, these results provide new insight into secondary injury after SCI and support further investigation of PLD3 as a potential therapeutic target.