Figure 1. BW-031 inhibition of human Nav1.7 channels and sodium
channels in iPSC-derived nociceptors.
a , Chemical structures of lidocaine, QX-314 and BW-031.b , Whole-cell patch clamp
recordings illustrating use-dependent inhibition of
hNav1.7 channels expressed in HEK 293 cells by 30 µM
intracellular QX-314 (blue) or BW-031 (red) or with the use-dependent
protocol run with control intracellular solution (black).
hNav1.7 current was evoked by 20-ms depolarizations from
-100 to -20 mV. After an initial stimulation at 0.05 Hz, trains of
depolarizations at frequencies from 0.33 to 10 Hz were delivered, each
for 1 minute (0.33 to 3 Hz) or 30 seconds (5 and 10 Hz), with a 1 minute
rest between trains. c , Dose-dependent inhibition by various
intracellular concentrations of QX-314 (blue) and BW-031 (red). Mean±SEM
(n=6 for 30,100, and 300 µM QX-314 and for 3, 10, 30, and 100 µM BW-031,
n=4 for 3 and 10 µM QX-314, n=3 for 300 µM BW-031). Solid lines, best
fits to (1/1 + [Drug]/IC50), where [Drug] is the
QX-314 or BW-031 concentration and IC50 is the
half-blocking concentration, with IC50=61 µM for QX-314
and IC50=9.2 µM for BW-031. Current was quantified
during the final slow (0.05 Hz) stimulation following the
higher-frequency trains of stimulation. d , Use-dependent
inhibition of hNav1.7 channels by 100 µM intracellular
BW-031 (red) contrasted with the same voltage protocol in control
(black) or after application of 100 µM extracellular BW-031 (green).e, Intracellular 100 µM BW-031 inhibits hNav1.7
more strongly (to 0.14±0.03, n=6) than intracellular 100 µM QX-314
(0.40±0.07, n=6; p=0.008, two-tailed Mann Whitney Test) or extracellular
100 µM BW-031 (0.86±0.04, n=6; p=0.008). ns p>0.05 and
**p<0.01. Black symbols are mean±SEM (0.94±0.01, n=36) for
control cells in which the same sequence of stimuli was delivered using
intracellular solution without compound. f , Use-dependent
inhibition of native Nav currents in hiPSC-derived
nociceptors by 100 µM intracellular QX-314 (blue) or 100 µM
intracellular BW-031 (red), and Nav currents in
untreated control neurons after the same voltage protocol (black)g, Collected results for hiPSC-derived nociceptors showing
stronger inhibition by 100 µM intracellular BW-031 (red, 0.13±0.04, n=5)
compared to 100 µM intracellular QX-314 (blue, 0.43±0.07, n=5) or
control (black, 0.95±0.03, n=4). Control vs. QX-314, p=0.0004; control
vs. BW-031, p<0.0001; BW-031 vs. QX-314, p=0.01, two-tailed
paired t-test. *p<0.05, ***p<0.001.