Automated high throughput patch clamp studies of voltage gated ion channels in hiPSC-derived neurons
Human induced pluripotent stem cell (hiPSC) derived neurons express native complements of human ion channels and their accessory proteins providing enhanced translatability from early in vitro studies to patient biology. Despite this promise, few studies have examined the suitability of hiPSC neurons for automated patch clamp studies. Here, we establish the feasibility of recording voltage gated channel activity from hiPSC derived excitatory neurons in 384 well format with the Sophion Qube automated patch clamp system.
hiPSC derived neurons were generated by overexpression of the transcription factor NGN2 driven from a stably integrated cassette in the AAVS1 locus. We first optimized dissociation procedures with 2-3 weeks in vitro NGN2 neurons by assessing the percentage of cells with voltage-gated sodium (NaV) and potassium (KV) currents on the Qube 384 system. Recordings following optimized dissociation found that ~30% of single cells had NaV currents >200 pA, leading to recordings of >100 cells in parallel. Minimal reduction of experimental throughput was observed with recordings following culture up to four weeks. Isolation of NaV currents with cesium internal solution showed expected NaV activation and inactivation curves with mean NaV currents >1 nA. Exchange of intracellular solution from cesium to potassium-based reversed block of KV channels did not significantly impact recording success rate. In multi-cell recording configurations, we attained success rates of ~80%, sufficient to examine dozens of experimental conditions simultaneously.
These results suggest that key hiPSC NGN2 neuronal properties, NaV and Kv activity, are retained in conditions that support high throughput patch clamp studies. Furthermore, we show that the automated patch clamp drastically increases experimental throughput for hiPSC neuron neurophysiology. Future studies will examine properties of other hiPSC derived neuronal types and establish the diversity of ion channels amendable to automated recordings.