Abstract
Objectives: Human nucleus pulposus cells (HNPCs), the primary cellular constituents of the intervertebral disc, are central to the pathogenesis of intervertebral disc degeneration (IVDD). Oxidative stress-induced mitochondrial dysfunction leads to intracellular metabolic imbalance and has been implicated in IVDD. This study investigated the role and molecular mechanism of glutamate dehydrogenase 1 (GLUD1) in hydrogen peroxide (H2O2)-challenged HNPCs relevant to IVDD. Methods: HNPCs were exposed to H2O2 to establish an oxidative stress model. Cell viability was assessed using the CCK-8 assay. Mitochondrial function was evaluated by measuring the oxygen consumption rate (OCR) and mitochondrial membrane potential. GLUD1 expression was quantified by qRT-PCR and Western blotting. The regulatory relationship between METTL3 and GLUD1 was examined by MeRIP-qPCR and a luciferase reporter assay. Results: H2O2 treatment decreased OCR and mitochondrial membrane potential in HNPCs and reduced alpha-ketoglutarate (α-KG) levels and GLUD1 expression. GLUD1 knockdown exacerbated H2O2-induced mitochondrial dysfunction, whereas GLUD1 overexpression alleviated it. METTL3 regulated GLUD1 mRNA stability by inducing GLUD1 m6A modification via YTHDF2, thereby modulating H2O2-induced mitochondrial dysfunction. Conclusion: GLUD1 protects HNPCs from H2O2-induced mitochondrial dysfunction through the glutamate/α-KG metabolic axis.