A BRD4/p300/SP1 epigenetic cascade drives microglial P2X4R transcription and promotes neuropathic pain

Persistent upregulation of the purinergic receptor P2X4R is strongly associated with microglial activation in neuropathic pain, yet the epigenetic mechanisms linking chromatin remodeling to its dysregulation remain unclear. Here, we delineate a hierarchical epigenetic cascade that promotes transcriptional activation of P2X4R in spinal microglia following nerve injury. In a mouse spared nerve injury (SNI) model, microglial activation was accompanied by increased expression of P2X4R and the histone acetyltransferase p300, together with enhanced histone acetylation (H3K9ac, H3K27ac, H4K5ac, and H4K8ac) and increased chromatin accessibility at the P2rx4 promoter. Microglia-specific deletion of p300 blunted injury-induced histone acetylation and suppressed P2X4R upregulation. We further demonstrate that the acetylation reader BRD4 is recruited to these regions and cooperates with the transcription factor SP1 to drive P2rx4 transcription, supported by chromatin analyses revealing inducible assembly of a BRD4–p300–SP1 axis. Disruption of this cascade via p300 inhibition (C646) or BRD4 blockade (JQ1) attenuated spinal neuroinflammation and alleviated nociceptive hypersensitivity. Notably, reactivation of P2X4R by BzATP largely reversed the analgesic effects of BRD4 inhibition, establishing P2X4R as a critical downstream effector. Collectively, these findings support a p300–BRD4–SP1 epigenetic cascade linking chromatin remodeling to microglia-mediated neuropathic pain, highlighting this pathway as a potential therapeutic target. Schematic illustrating sequential p300-mediated acetylation of histones H3 and H4, followed by BRD4-dependent assembly of a BRD4–p300–SP1 transcriptional cascade that drives P2rx4 transactivation, leading to dorsal spinal microglial activation and neuropathic pain in the mouse SNI model (sciatic nerve ligation at lumbar levels L4–L6). Pharmacological inhibition of p300 (C646) or BRD4 (JQ1) disrupts this pathway and attenuates microglial activation and pain.