H3K27 trimethylation-mediated downregulation of miR-216a-3p in sensory neurons regulates neuropathic pain behaviors via targeting STIM1.

Abstract

Although the therapeutic potential of miRNA-mediated gene regulation has been investigated, its precise functional regulatory mechanism in neuropathic pain remains incompletely understood. In this study, we elucidate that miR-216a-3p serves as a critical non-coding RNA involved in the modulation of trigeminal-mediated neuropathic pain. By conducting RNA-seq and qPCR analysis, we observed a notable decrease of miR-216a-3p in the injured trigeminal ganglia (TG) of male rats. Intra-TG administration of miR-216a-3p agomir or lentiviral-mediated overexpression of miR-216a-3p specifically in sensory neurons of injured TGs alleviated established neuropathic pain behaviors, while downregulation of miR-216a-3p (pharmacologically or genetically) in naïve rats induced pain behaviors. Moreover, nerve injury significantly elevated the H3K27 trimethylation (H3K27me3) levels in the ipsilateral TG, thereby suppressing the SRY-box transcription factor 10 (SOX10) binding to the miR-216a-3p promoter and resulting in the reduction of miR-216a-3p. Inhibiting the enzymes that responsible for catalyzing H3K27me3 restored the nerve injury-induced reduction in miR-216a-3p expression and markedly ameliorated neuropathic pain behaviors. Furthermore, miR-216a-3p targeted stromal interaction molecule 1 (STIM1), and the decreased miR-216a-3p associated with neuropathic pain caused a significant upregulation in the protein abundance of STIM1. Conversely, overexpression of miR-216a-3p in the injured TG suppressed the upregulation of STIM1 expression and reversed the mechanical allodynia. Together, the mechanistic understanding of H3K27me3-dependent SOX10/miR-216a-3p/STIM1 signaling axial in sensory neurons may facilitate the discovery of innovative therapeutic strategies for neuropathic pain management.Significance Statement miRNAs are posttranscriptional regulators of gene expression that play critical roles in the pathogenesis of neuropathic pain. However, the detailed mechanisms by which most pain-associated miRNAs operate and their therapeutic potential are incompletely understood. Our present study revealed that nerve injury-induced trimethylation of lysine 27 on histone H3 (H3K27me3) reduces the binding of SOX10, a transcription factor, to the promoter region of the miR-216a-3p gene, leading to decreased expression of the microRNA, miR-216a-3p. This reduction subsequently promotes neuropathic pain by regulating STIM1. Given that miRNA-mediated gene regulation is a proposed therapeutic approach for treating neuropathic pain, our findings suggest that replenishing miR-216a-3p could serve as a novel strategy for treating chronic neuropathic pain.