Intranasal CRMP2-Ubc9 inhibitor regulates NaV1.7 to alleviate trigeminal neuropathic pain

Abstract

Dysregulation 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 compound 194, which inhibits CRMP2 SUMOylation mediated by the SUMO-conjugating enzyme Ubc9. We further demonstrated that 194 effectively reduces the functional activity of NaV1.7 channels in dorsal root ganglia neurons and alleviated inflammatory and neuropathic pain. Here, we used a comprehensive array of 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 of Scn9a, Dpysl2, and UBE2I within TG neurons. Furthermore, we found an interaction between CRMP2 and NaV1.7, with CRMP2 being SUMOylated in these sensory ganglia. Disrupting CRMP2 SUMOylation with compound 194 uncoupled the CRMP2/NaV1.7 interaction, impeded NaV1.7 diffusion on the plasma membrane, and subsequently diminished NaV1.7 activity. Compound 194 also led to a reduction in TG neuron excitability. Finally, when intranasally administered to rats with chronic constriction injury of the infraorbital nerve, 194 significantly 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.

Peptide and Peptidomimetic Inhibitors Targeting the Interaction of Collapsin Response Mediator Protein 2 with the N-Type Calcium Channel for Pain Relief

“…The CBD3 peptide is in proximity of three tyrosine phosphorylation sites (Y32, Y479, and Y499) which may be activated by semaphorin signaling related to the canonical functions of CRMP2 . Related to our focus on pain is that in the subunit adjacent to the CBD3 core peptide is lysine 374 (Figure B), the CRMP2 SUMOylation site that regulates interactions with Na V 1.7. ,, We developed a compound (benzoylated 2-(4-piperidinyl)-1,3-benzimidazole, named 194) that inhibits SUMOylation at this site and alleviates chronic pain in multiple animal models through disruption of CRMP2–Na V 1.7 binding. − ,− Some portion of CRMP2 is natively SUMOylated. , We found that CBD3063 does not alter CRMP2 SUMOylation levels, but it will be interesting to know if inhibition of CRMP2 SUMOylation by 194 alters the effects of CBD3 and CBD3063 as the predicted binding site for 194 is also adjacent to the CBD3 core peptide in the tetramer (Figure B). If the compounds do not interfere with each other’s function, this would raise the possibility that CBD3063 and 194 could be used effectively together.…”

Pathology of pain and its implications for therapeutic interventions

“… 304 Antagonists targeting CRMP2/Ubc9 axis have shown desirable performances in trigeminal neuropathic pain relief. 305 Importantly, CRMP2 SUMOylation occurs in chronic neuropathic pain, rather than physiological pain. 301 Therapies against this mechanism may have fewer side effects of losing sensations of normal acute pain.…”