LncRNA Rmst-driven DNMT3A mRNA stabilization through HuR: implications for neuropathic pain therapy.

Objective: This study aimed to explore the role of lncRNA Rmst in regulating DNA methyltransferase 3A (DNMT3A) expression and its impact on neuropathic pain (NP).

Methods: A SAM-based lncRNA library screening system was employed to identify lncRNAs regulating DNMT3a stability. Spared nerve injury (SNL) and chronic constriction injury (CCI) rat models of neuropathic pain were established. LncRNA Rmst was knocked down in injured dorsal root ganglia via microinjection of siRmst. Lentiviral vectors carrying siRmst or pcDNA-DNMT3A were constructed and injected into mouse spinal cords. Analyses included qRT-PCR, Western blot, in situ hybridization, immunofluorescence, dual-luciferase reporter assays, and RNA immunoprecipitation (RIP). Pain-related behaviors were assessed using behavioral tests.

Results: We identified 121 lncRNAs that could enhance DNMT3A stability, and Rmst was among the five lncRNAs significantly upregulated in the neuropathic pain model. In SNL and CCI rat models, knockdown of Rmst led to downregulation of DNMT3A expression, reduced neuronal excitability, inhibited microglial activation, and decreased release of inflammatory factors. The expression of DNMT3A increased over time in both models, and it was positively correlated with Rmst. Mechanistically, Rmst interacted with the -RNA-binding protein HuR to stabilize DNMT3A mRNA. Overexpression of DNMT3A in mice increased pain sensitivity, pro-inflammatory cytokine expression, and microglial activation.

Conclusions: LncRNA Rmst binds to HuR to enhance the stability of DNMT3A mRNA, thereby facilitating neuropathic pain progression. Targeting the Rmst-HuR-DNMT3A axis could represent a promising therapeutic approach for neuropathic pain.