Physiological 17β-oestradiol inhibits KV7.4 currents via GPER1-dependent PLC/PKC signalling.

KV7.4 channels are important regulators of membrane potential and excitability in multiple tissues and are emerging as key effectors of steroid hormone signaling. Here, 17β-estradiol (E2) was examined as a modulator of recombinant KV7.4 channels expressed in HEK293 cells. Whole-cell patch-clamp recordings showed that acute application of E2 reduced KV7.4 current density. At nanomolar concentrations, both E2 and the alternate GPER1 agonist aldosterone inhibited KV7.4 currents only when G protein-coupled estrogen receptor 1 (GPER1) was co-expressed, indicating a receptor-dependent mechanism. Pharmacological inhibition showed that phospholipase C (PLC) and protein kinase C (PKC), but not adenylyl cyclase, contribute to GPER1-mediated inhibition of KV7.4. In contrast, equivalent experiments performed with KV7.5 channels showed no significant effect of E2 despite GPER1 co-expression, suggesting subtype-selective regulation within the KV7 family. Surface biotinylation experiments suggest that GPER1 co-expression reduced surface KV7.4 expression, with a further reduction observed following E2 treatment. Finally, both E2 and aldosterone negatively regulate the sensitivity of KV7.2-5 activator ML213-mediated relaxation in arteries from female rats. Together, these findings identify KV7.4 as a downstream effector of rapid GPER1-dependent estrogen signaling and suggest that steroid status may influence KV7-targeted therapeutic responses.