This project aims to identify transcriptional repressors specifically recruited by histone H3 lysine 18 lactylation (H3K18la) in the nucleus pulposus cell context. Nucleus pulposus cells were cultured under lactic acid conditions to induce lactylation. Proteins interacting with H3K18la were immunoprecipitated using a specific H3K18la antibody, with parallel control pulldowns performed using normal IgG. The co-precipitated proteins from three biological replicates per condition were then analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The comparative IP-MS analysis between the H3K18la-IP and IgG control groups is designed to screen for putative transcriptional repressors that are selectively enriched by the H3K18la epigenetic mark.