DNMT3a-mediated GluN2B desilencing in the anterior cingulate cortex underlies chemotherapy-induced neuropathic pain

Chemotherapy-induced neuropathic pain (CINP) involves chemotherapy toxicity to cortical tissues. DNA methylation, a key epigenetic mechanism for gene regulation, has been implicated in neuropathic pain pathogenesis. The anterior cingulate cortex (ACC) is critical for pain processing, yet its susceptibility to DNA methylation-mediated epigenetic regulation remains unexplored. In a mouse model of paclitaxel (PTX)-induced CINP, we found that PTX downregulated DNA methyltransferase 3a (DNMT3a) in the ACC and induced mechanical and thermal pain hypersensitivity. Overexpression of DNMT3a specifically in ACC pyramidal neurons alleviated these PTX-induced nociceptive behaviors, whereas knockdown of DNMT3a in the ACC alone was sufficient to produce pain hypersensitivity. Western blot analysis revealed that PTX selectively upregulated GluN2B, but not other NMDA (GluN1, GluN2A), AMPA (GluA1, GluA2), or GABA_A receptor subunits. Mechanistically, pyramidal neuron-specific DNMT3a overexpression in the ACC silenced GluN2B expression in a DNA methylation-dependent manner, consequently suppressing GluN2B-mediated NMDA currents in ACC pyramidal neurons. Furthermore, intra-ACC application of the GluN2B antagonist Ifenprodil reversed pain hypersensitivity induced by either PTX or DNMT3a knockdown. Finally, our results establish DNMT3a-mediated epigenetic desilencing of GluN2B in the ACC as a key mechanism underlying PTX-induced neuropathic pain, identifying both as promising therapeutic targets for CINP.