John P.Snow GrantWestlake Lindsay K.Klofas SoyounJeon Laura C.Armstrong Kathryn J.Swoboda Alfred L.GeorgeJr Kevin C.Ess
https://doi.org/10.1016/j.nbd.2020.104881
Highlights
- iPSCs and isogenic corrected controls were generated from an AHC patient harboring a heterozygous E815K mutation in ATP1A3.•
- ATP1A3+/E815K iPSC-derived cortical neurons show increased expression of ATP1A3 mRNA compared to control cells.•
- ATP1A3+/E815K neurons are hyperactive following heat stress, replicating trigger-induced symptoms seen in AHC.•
- Treatment with the commonly used AHC drug flunarizine did not rescue stress-induced hyperactivity in ATP1A3+/E815K neurons.
Abstract
Alternating hemiplegia of childhood (AHC) is a rare neurodevelopmental disease caused by heterozygous de novo missense mutations in the ATP1A3 gene that encodes the neuronal-specific α3 subunit of the Na,K-ATPase (NKA) pump. Mechanisms underlying patient episodes including environmental triggers remain poorly understood, and there are no empirically proven treatments for AHC. In this study, we generated patient-specific induced pluripotent stem cells (iPSCs) and isogenic controls for the E815K ATP1A3 mutation that causes the most phenotypically severe form of AHC. Using an in vitro iPSC-derived cortical neuron disease model, we found elevated levels of ATP1A3 mRNA in AHC lines compared to controls, without significant perturbations in protein expression. Microelectrode array analyses demonstrated that in cortical neuronal cultures, ATP1A3+/E815K iPSC-derived neurons displayed less overall activity than neurons differentiated from isogenic mutation-corrected and unrelated control cell lines. However, induction of cellular stress by elevated temperature revealed a hyperactivity phenotype following heat stress in ATP1A3+/E815K neurons compared to control lines. Treatment with flunarizine, a drug commonly used to prevent AHC episodes, did not impact this stress-triggered phenotype. These findings support the use of iPSC-derived neuronal cultures for studying complex neurodevelopmental conditions such as AHC and provide a platform for mechanistic discovery in a human disease model.