Ebio-1

Although men have historically exhibited higher levels of alcohol use disorder (AUD) diagnosis, the gap between men and women has been diminishing quickly. Preclinical screening for pharmacological treatments for AUD has typically focused solely on males, ignoring the possibility that males and females may differ mechanistically for the same behavioral phenotype. To ensure the efficacy of treatment targets across the sexes, it is crucial to study the pharmacological effects of AUD treatments in males and females. While positive K_Ca2 channel modulation can reduce ethanol consumption and seeking behaviors, withdrawal-induced hyperexcitability, and negative affective behaviors in male rodents, the effect of K_Ca2 channel modulation on female ethanol consumption has not been reported. To determine the efficacy of K_Ca2 channel positive modulation in female C57BL/6J mice, we assessed the ability of the K_Ca2 channel positive modulator 1-EBIO to affect locomotor activity, voluntary home cage ethanol intake prior to and following chronic intermittent ethanol (CIE) exposure, and voluntary home cage sucrose drinking. There were no significant changes to distance traveled in an open field apparatus following administration of 1-EBIO in our locomotor assay. In ethanol drinking mice, 1-EBIO significantly reduced ethanol consumption in air controls and CIE exposed mice, without altering water consumption. While administration of 1-EBIO did not affect consumption of sucrose in male mice, 1-EBIO significantly increased sucrose intake in females. Together, these data provide further evidence that K_Ca2 channel positive modulation is a promising therapeutic target to reduce ethanol drinking in males and females alike.

Pharmacological activation of voltage-gated ion channels by ligands serves as the basis for therapy and mainly involves a classic gating mechanism that augments the native voltage-dependent open probability. Through structure-based virtual screening, we identified a new scaffold compound, Ebio1, serving as a potent and subtype-selective activator for the voltage-gated potassium channel KCNQ2 and featuring a new activation mechanism. Single-channel patch-clamp, cryogenic-electron microscopy and molecular dynamic simulations, along with chemical derivatives, reveal that Ebio1 engages the KCNQ2 activation by generating an extended channel gate with a larger conductance at the saturating voltage (+50 mV). This mechanism is different from the previously observed activation mechanism of ligands on voltage-gated ion channels. Ebio1 caused S6 helices from residues S303 and F305 to perform a twist-to-open movement, which was sufficient to open the KCNQ2 gate. Overall, our findings provide mechanistic insights into the activation of KCNQ2 channel by Ebio1 and lend support for KCNQ-related drug development.