(S)-lacosamide inhibition of CRMP2 phosphorylation reduces postoperative and neuropathic pain behaviors through distinct classes of sensory neurons identified by constellation pharmacology

Abstract

Chronic pain affects the life of millions of people. Current treatments have deleterious side effects. We have advanced a strategy for targeting protein interactions which regulate the N-type voltage-gated calcium (CaV2.2) channel as an alternative to direct channel block. Peptides uncoupling CaV2.2 interactions with the axonal collapsin response mediator protein 2 (CRMP2) were antinociceptive without effects on memory, depression, and reward/addiction. A search for small molecules that could recapitulate uncoupling of the CaV2.2–CRMP2 interaction identified (S)-lacosamide [(S)-LCM], the inactive enantiomer of the Food and Drug Administration–approved antiepileptic drug (R)-lacosamide [(R)-LCM, Vimpat]. We show that (S)-LCM, but not (R)-LCM, inhibits CRMP2 phosphorylation by cyclin dependent kinase 5, a step necessary for driving CaV2.2 activity, in sensory neurons. (S)-lacosamide inhibited depolarization-induced Ca2+ influx with a low micromolar IC50. Voltage-clamp electrophysiology experiments demonstrated a commensurate reduction in Ca2+ currents in sensory neurons after an acute application of (S)-LCM. Using constellation pharmacology, a recently described high content phenotypic screening platform for functional fingerprinting of neurons that uses subtype-selective pharmacological agents to elucidate cell-specific combinations (constellations) of key signaling proteins that define specific cell types, we investigated if (S)-LCM preferentially acts on certain types of neurons. (S)-lacosamide decreased the dorsal root ganglion neurons responding to mustard oil, and increased the number of cells responding to menthol. Finally, (S)-LCM reversed thermal hypersensitivity and mechanical allodynia in a model of postoperative pain, and 2 models of neuropathic pain. Thus, using (S)-LCM to inhibit CRMP2 phosphorylation is a novel and efficient strategy to treat pain, which works by targeting specific sensory neuron populations.

CRMP2 and voltage-gated ion channels: potential roles in neuropathic pain

“…Importantly, CRMP2-derived peptides did not demonstrate toxicity or other adverse side effects associated with targeting VGCCs via direct and state-dependent channel blockers. CRMP2-targeted small molecules in development against VGSCs as well as VGCCs [92, 100–101, 103, 117, unpublished data] have also shown similar profiles of preclinical success. Together, this work precipitates the necessary advancement of CRMP2-centered drug discovery ventures into studies for diverse clinical pain indications and other channelopathies.…”

“…In parallel, it was discovered that phosphorylation of CRMP2 by Cdk5 dynamically regulates and increases the association of CRMP2 with Cav2.2 [102]. While activation of Cdk5 and increased CRMP2 expression in rat DRGs contribute to several pain phenotypes, ( S )-LCM biochemically disrupts the CRMP2-Cav2.2 interaction while inhibiting depolarization-evoked Ca 2+ influx and Ca 2+ currents [46, 49, 102–103]. Systemic administration of ( S )-LCM to mice, at three daily doses of 20 mg/kg over four days, successfully uncoupled the CRMP2-Cav2.2 interaction in brain lysates, with no detectable effects on locomotion, feeding, or behavior [103].…”

“…While activation of Cdk5 and increased CRMP2 expression in rat DRGs contribute to several pain phenotypes, ( S )-LCM biochemically disrupts the CRMP2-Cav2.2 interaction while inhibiting depolarization-evoked Ca 2+ influx and Ca 2+ currents [46, 49, 102–103]. Systemic administration of ( S )-LCM to mice, at three daily doses of 20 mg/kg over four days, successfully uncoupled the CRMP2-Cav2.2 interaction in brain lysates, with no detectable effects on locomotion, feeding, or behavior [103]. In experimental rodent models of SNL- and SNI-induced neuropathic pain, ( S )-LCM administration effectively reversed nociceptive behaviors within 30 minutes and 120 minutes, respectively [103].…”

“…Systemic administration of ( S )-LCM to mice, at three daily doses of 20 mg/kg over four days, successfully uncoupled the CRMP2-Cav2.2 interaction in brain lysates, with no detectable effects on locomotion, feeding, or behavior [103]. In experimental rodent models of SNL- and SNI-induced neuropathic pain, ( S )-LCM administration effectively reversed nociceptive behaviors within 30 minutes and 120 minutes, respectively [103]. These findings add the inhibition of Cdk5-mediated phosphorylation of CRMP2 as a potential therapeutic strategy for eliminating chronic pain.…”

Blocking CRMP2 SUMOylation reverses neuropathic pain

“…Here, we illustrate the potential of such targeting applied to a chronic pain model. Inhibiting CRMP2 interactions 16 or phosphorylation 17 has highlighted a central role for this protein in pain signaling transmission. Exactly how this is achieved is not known, but recent studies point to the regulation of voltage-gated ion channels by CRMP2 as a possible link.…”