ELECTROPHYSIOLOGICAL CHARACTERIZATION OF NA<SUB>V</SUB>1.7 AND K<SUB>V</SUB>7.2/3 CHANNELS IN HUMAN IPSC-DERIVED SENSORY NEURONS

The voltage-gated sodium channel Na_v1.7, encoded by SCN9A, is a critical regulator of pain signaling in peripheral sensory neurons. Mutations in this channel cause severe inherited pain disorders, highlighting Na_v1.7 as an attractive target for novel analgesics. The voltage-gated potassium channel K_v7.2/3, encoded by KCNQ2 and KCNQ3, stabilizes the neuronal resting membrane potential and regulates excitability in both central and peripheral neurons. Mutations in this channel are associated with neurological disorders. Pharmacological activation of K_v7.2/3 has, therefore, emerged as a therapeutic strategy for epilepsy, and pain. Studies on cell cultures are essential for the preclinical validation of drug candidates. Human induced pluripotent stem cell–derived sensory neurons (hiPSC-SNs; iCell) represent an ideal in vitro model that overcomes the limited availability of primary dorsal root ganglion neurons.
This study aims to characterize Na_v1.7 and K_v7.2/3 channel expression in hiPSC-SNs using manual patch-clamp, and to evaluate suitability of hiPSC-SNs for drug discovery applications targeting both channels. Na_v1.7 expression in iCells was assessed under voltage-clamp conditions by examining inhibition of the TTX-sensitive sodium currents by selective Na_v1.7 blockers GDC-0276 and GDC-0310. Both compounds preferentially inhibited the inactivated state of the channel, providing clear evidence for Na_v1.7 expression. K_v7.2/3 channel activity in iCells was evaluated under current-clamp conditions. Application of a selective K_v7.2/3 activator XEN-1101 reduced action potential firing, thus indicating the expression of K_v7.2/3. Together, these findings demonstrate evidence for Na_v1.7 and K_v7.2/3 expression in hiPSC-SNs, and support the translational relevance of this cell model for epilepsy- and pain-related drug development.