Zerumbone alleviates TRESK- and TRPV1-mediated ion currents and reduces excitability of human iPSC-derived nociceptor-like neurons.

Secondary plant metabolites are widely used in traditional and naturopathic medicine to treat pain, infection, and inflammation. The sesquiterpenoid zerumbone, derived from the edible ginger Zingiber zerumbet, has been shown to exert analgesic, antioxidant, antitumoral, and antimicrobial effects in preclinical models, acting through multiple receptor systems including cannabinoid (CB) receptors, peroxisome proliferator-activated receptors, N-methyl-D-aspartate (NMDA) receptors, and the serotonergic system. Zerumbone also modulates inflammatory and nitric oxide-cGMP-K+ATP signaling pathways implicated in antiallodynic responses, yet its direct impact on nociceptor-associated ion channels like the Transient receptor potential vanilloid 1 (TRPV1) and the Twik-related spinal cord potassium channel (TRESK) in human cellular systems remains poorly characterized. In the present study, the antinociceptive properties of zerumbone were investigated in human HEK293-based and induced pluripotent stem cell (iPSC)-derived nociceptor models. Here, the zerumbone treatment reduced cell viability and proliferation in a concentration-dependent manner without altering TRPV1 or TRESK protein expression. Whole-cell patch-clamp recordings revealed that zerumbone reversibly inhibited TRESK-mediated outward potassium currents upon direct application, whereas bath-applied zerumbone increased outward currents, suggesting context-dependent modulation. In TRPV1-expressing HEK293 cells, SH-SY5Y neuroblastoma cells, and human iPSC-derived nociceptors, zerumbone reduced TRPV1-mediated ion currents and capsaicin-evoked calcium signals, indicating a direct or competitive inhibitory effect on TRPV1 activity. In iPSC-derived nociceptors, zerumbone decreased action potential firing at moderate depolarizing currents, shifted the resting membrane potential, and increased rheobase, consistent with reduced nociceptor excitability, while no significant changes in TRESK-mediated currents were detected. These data suggest that zerumbone attenuates human iPSC-derived nociceptor-like neuron excitability largely via TRPV1 inhibition, with a more complex, concentration- and application-method-dependent modulation of TRESK. The findings provide a mechanistic basis for the antiallodynic effects of zerumbone observed in rodent models and highlight the need for further studies in human-derived systems to clarify the precise channel-level interactions and their relevance to inflammatory and neuropathic pain.