Figure 2. KCNQ2 gene inactivation by CRISPR/Cas9 impaires M-currents in iCas9- hPSCs-derived neurons.

(a) Voltage-clamp recordings of XE991-sensitive currents. Left, examples of traces recorded from a control neuron in response to a 1-s voltage step from −20 mV to −60 mV before and after extracellular perfusion with 20 μM XE991. Middle, traces obtained in the same conditions in a sgRNA-K6-targeted neuron. Right, current-voltage plot of steady-state amplitudes of XE991-sensitive currents in control and sgRNA-K6-treated neurons (n = 10 and 7, respectively, *p < 0.05). (b) Pharmacological study of the activity of the KCNQ2 channel in hPSC-derived neurons (ctr and sgRNA-K6) and primary hippocampal neurons (hip) by extracellular electrophysiology. XE991 has been used in three different concentrations (0.002, 2, 20 μM) represented by the increasing intensity of colours. Four functional parameters are shown: the number of active channels, the average spike number, the average number of channels involved in a network burst and the network burst frequency. Each bar represents the average value ± SEM on a 10-minute window of recording for each parameter and XE991 concentration (n = 3 for ctr and sgRNA-K6, n = 8 for hip, *p < 0.05).