Excessive compression induces cartilage endplate degeneration via the Piezo1/NAT10/mTOR signaling axis.

OBJECTIVE: Cartilage endplate (CEP) is one of the most important components of the functional unit of the spine, and its performance is closely related to mechanical compression. N4-acetylcytidine (ac4C) modification, a recently identified RNA modification, is implicated in the onset and progression of numerous diseases. This study aimed to investigate the role and mechanism of ac4C modification in the process of CEP degeneration induced by excessive compression. METHOD: We validated the regulatory effects of N-acetyltransferase 10 (NAT10) through in vitro cell compressive loading model and rat lumbar instability model. The mechanism by which NAT10 mediates the ac4C modification in regulating the stability of mammalian target of rapamycin (mTOR) expression was validated using techniques such as acRIP-seq, RNA-seq, RT-qPCR, acRIP-qPCR and so on. Electron microscopy and mRFP-GFP-LC3 were used to validate the role of autophagy regulated by mTOR in disrupting metabolic homeostasis. Finally, the regulatory effect of cell signaling related to ac4c modification was investigated using luciferase assays, and other techniques. RESULTS: Under excessive compression, NAT10 enhanced mTOR expression through ac4C modification. This upregulation suppressed cellular autophagy, resulting in heightened apoptosis of cartilage endplate cells (CEPCs), accelerated extracellular matrix degradation, and promoted intervertebral disc degeneration. Furthermore, we discovered that Piezo1 can augment the transcriptional activity of the NAT10 promoter via P65 in response to excessive compression. CONCLUSION: We have elucidated the mechanisms by which ac4C modification, mediated by NAT10, contributes to apoptosis and the imbalance of extracellular matrix metabolism in CEPCs under excessive compression.