FAM3A Protects HT22 Cells Against Hydrogen Peroxide-Induced Oxidative Stress Through Activation of PI3K/Akt but not MEK/ERK Pathway

Abstract

Background/Aims: Oxidative stress-induced cell damage is involved in many neurological diseases. FAM3A is the first member of family with sequence similarity 3 (FAM3) gene family and its biological function remains largely unknown. Methods: This study aimed to determine its role in hydrogen peroxide (H₂O₂) induced injury in neuronal HT22 cells. The protective effects were measured by cell viability, lactate dehydrogenase (LDH) release and apoptosis, and oxidative stress was assayed by reactive oxygen species (ROS) generation, ATP synthesis and lipid peroxidation. By using selective inhibitors, the involvement of PI3K/Akt and MEK/ERK pathways were also investigated. Results: The results of fluorescence staining revealed that H₂O₂ significantly decreased the expression of FAM3A protein, which was shown to be subcellularly located in mitochondria. Up-regulation of FAM3A by lentivirus transfection markedly increased cell viability and decreased LDH release after H₂O₂ treatment. The anti-apoptotic activity of FAM3A was demonstrated by the reduced mitochondrial cytochrome c release, decreased activation of caspase-3 and the results of flow cytometry. Overexpression of FAM3A attenuated intracellular ROS generation and loss of ATP production induced by H₂O₂, and subsequently inhibited lipid peroxidation. In addition, overexpression of FAM3A significantly increased the activation of Akt and ERK in H₂O₂ injured HT22 cells. By using Akt and ERK specific inhibitors, we found that inhibition of PI3K/Akt, but not MEK/ERK pathway, partially prevented FAM3A-induced protection against H₂O₂. Conclusion: These results suggest that FAM3A has protective effects against H₂O₂-induced oxidative stress by reducing ROS accumulation and apoptosis, and these protective effects are dependent on the activation of PI3K/Akt pathway.