EZH2-mediated PHLDA1 governs mitochondrial dysfunction and oxidative damage in traumatic brain injury via the AKT/Nrf2/Sirt3 pathway.

Objective: This study investigates the role of pleckstrin homology-like domain family A member 1 (PHLDA1) in traumatic brain injury (TBI) and examines how its knockdown may mitigate neurological impairments associated with TBI, focusing on mitochondrial dysfunction, neuro-inflammation, and oxidative stress.

Methods: TBI was induced in rats, and PHLDA1 expression was assessed through qPCR and Western blot. Neurological functions were evaluated via grip strength, balance beam, and rotarod tests. Brain tissue samples were analyzed for edema, apoptosis, and mitochondrial activity. Additionally, the effects of PHLDA1 knockdown on protein kinase B/nuclear factor erythroid 2-related factor 2/sirtuin 3 (AKT/Nrf2/Sirt3) signaling were examined in H 2 O 2 -treated PC12 cells, with the AKT inhibitor MK-2206 used to explore pathway interactions.

Results: PHLDA1 levels were elevated in TBI rats, correlating with impaired neurological function, brain edema, and increased cell apoptosis. PHLDA1 knockdown improved motor performance, reduced edema, decreased apoptotic cell counts, and alleviated inflammation. Furthermore, it restored mitochondrial membrane potential and increased ATP production. In cell models, PHLDA1 knockdown reduced oxidative stress and enhanced AKT/Nrf2/Sirt3 pathway activation, which MK-2206 partially reversed. Additional experiments indicated that EZH2 inhibited PHLDA1 transcription by binding to its promoter.

Conclusion: PHLDA1 knockdown mitigates TBI-induced neurodegeneration by reducing oxidative stress and enhancing mitochondrial function through the AKT/Nrf2/Sirt3 pathway. These findings suggest that targeting PHLDA1 may offer a novel therapeutic approach for TBI.