Intranasal CRMP2-Ubc9 Inhibitor Regulates NaV1.7 to Alleviate Trigeminal Neuropathic Pain

Abstract

AbstractDysregulation of voltage-gated sodium NaV1.7 channels in sensory neurons contributes to chronic pain conditions, including trigeminal neuropathic pain. We previously reported that chronic pain results in part from increased SUMOylation of collapsin response mediator protein 2 (CRMP2), leading to an increased CRMP2/NaV1.7 interaction and increased functional activity of NaV1.7. Targeting this feed-forward regulation, we developed compound194, which inhibits CRMP2 SUMOylation mediated by the SUMO-conjugating enzyme Ubc9. We further demonstrated that194effectively reduces the functional activity of NaV1.7 channels in dorsal root ganglia neurons and alleviated inflammatory and neuropathic pain. Here, we employed a comprehensive array of investigative approaches, encompassing biochemical, pharmacological, genetic, electrophysiological, and behavioral analyses, to assess the functional implications of NaV1.7 regulation by CRMP2 in trigeminal ganglia (TG) neurons. We confirmed the expression ofScn9a,Dpysl2, andUBE2Iwithin TG neurons. Furthermore, we found an interaction between CRMP2 and NaV1.7, with CRMP2 being SUMOylated in these sensory ganglia. Disrupting CRMP2 SUMOylation with compound194uncoupled the CRMP2/NaV1.7 interaction, impeded NaV1.7 diffusion on the plasma membrane, and subsequently diminished NaV1.7 activity. Compound194also led to a reduction in TG neuron excitability. Finally, when intranasally administered to rats with chronic constriction injury of the infraorbital nerve (CCI-ION),194significantly decreased nociceptive behaviors. Collectively, our findings underscore the critical role of CRMP2 in regulating NaV1.7 within TG neurons, emphasizing the importance of this indirect modulation in trigeminal neuropathic pain.