PCIF1-mediated m6Am modification in ACC neurons participates in inflammatory pain and anxiety

N6,2'-O-dimethyladenosine (m⁶Am) modification, mediated by the methyltransferase phosphorylated CTD interacting factor 1 (PCIF1), is increasingly recognized as an important layer of gene regulation. However, the role of m⁶Am in pain and comorbid anxiety has not yet been explored. Here, we report that persistent peripheral inflammation reduces PCIF1 levels in the mouse anterior cingulate cortex (ACC). This downregulation is triggered by decreased binding of GLI2 to the Pcif1 promoter. Knocking out or conditionally deleting Pcif1 in ACC neurons reduces the m⁶Am level of Gap43 mRNA, leading to the increased expression of GAP43 and pre-long-term potentiation (LTP) oversaturation, which in turn results in inflammatory pain and its comorbid anxiety-like behavior. Conversely, knocking down GAP43 suppresses the pre-LTP oversaturation caused by PCIF1 reduction, thereby alleviating inflammatory pain and comorbid anxiety. This study reveals a mechanism whereby GLI2-governed PCIF1 contributes to the modulation of inflammatory pain and comorbid anxiety through the targeting of Gap43 m⁶Am in the ACC.