Characterization of hiPSC-derived neurological disease models using automated patch clamp (Qube and QPatch)
Human-induced pluripotent stem cells (hiPSCs) can be differentiated into multiple cell types, including neurons and cardiomyocytes. This gives rise to a novel way of establishing human disease models, which in turn can be used for drug development in vitro. Ion channels represent highly attractive therapeutic targets in the nervous and the cardiovascular system, rendering electrophysiological studies of hiPSCs important for their usage in drug discovery. However, such studies have traditionally been limited by the labour-intensive and low-throughput nature of patch-clamp electrophysiology. Here we use our automated patch clamp systems Qube 384 and QPatch 48 in order to increase throughput and reduce timelines.
Our observations include channel expression versus time in culture, the pharmacological dissection of endogenous ion channels (e.g. Nav and Kv), identification of ligand-gated receptors, and recordings of action potentials using the current clamp feature. Also, we show the electrophysiology of a spinal muscular atrophy (SMA) and an amyotrophic lateral sclerosis (ALS) model. The disease model for SMA was derived by mutations in the SMN1 gene and shows enhanced sodium channel activity but no shift in the normalized current-voltage relationship. ALS was here mimicked by a single point mutation in the superoxide dismutase 1 protein (SOD1), D90A, which had previously been identified in recessive, dominant and seemingly sporadic pedigrees. Cells carrying this point mutation displayed larger sodium currents, which eventually led to neurofilament aggregation, neurite degeneration and other phenotypes. We could confirm that the electrophysiological effect could be reversed by point mutation to D90D.
Our measurements validate the feasibility of measuring hiPSC ion channel currents using the APC platforms Qube and QPatch. Altogether, these results can facilitate evaluating the use of hiPSC for early drug development and in extension personal medicine.