Authors :
Presenting Author: Haeryung Kim, MD – Seoul National University Children’s Hospital, Seoul, Korea.
Young Ho Kim, MD – Seoul National University Children’s Hospital, Seoul, Korea.
Jong Ho Cha, MD – Seoul National University Children’s Hospital, Seoul, Korea.
Jee Min Kim, MD – Seoul National University Children’s Hospital, Seoul, Korea.
Jangsup Moon, MD, PhD. – Seoul National University Hospital, Seoul, South Korea.
Yong-Seok Lee, PhD – College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
Byung Chan Lim, MD, PhD. – Seoul National University Children’s Hospital, Seoul, Korea.
Ki Joong kim, MD, PhD. – Seoul National University Children’s Hospital, Seoul, Korea.
Jong-Hee Chae, MD, PhD. – Seoul National University Children's Hospital, Seoul, Republic of Korea
Woojoong kim, MD – Seoul National University Children’s Hospital, Seoul, Korea.
Rationale:
Mutations in the ATP1A3 gene are linked to a broad spectrum of neurodevelopmental and movement disorders. Although clinical recognition of ATP1A3-related syndromes has increased, the cellular mechanisms by which these mutations contribute to neuronal dysfunction remain incompletely understood. Several in vitro models using patient-specific induced pluripotent stem cells (iPSCs) have been developed to investigate ATP1A3-related pathomechanisms. However, despite the predominant expression of ATP1A3 protein in GABAergic neurons across various brain regions, no GABAergic in vitro model has been established to date, primarily due to the technical challenges in differentiation and maintaining GABAergic neurons.
Methods:
iPSCs were generated from urine-derived somatic cells of a patient harboring a heterozygous ATP1A3 variant, c.2443G >A (p.Glu815Lys), as well as from a healthy donor to create control iPSC. These iPSCs were differentiated into GABAergic neurons and subjected to whole-cell patch-clamp recordings to evaluate electrophysiological properties. iPSCs differentiation into GABAergic neurons was confirmed and characterized by immunostaining and fluorescent viral labeling. Electrophysiological parameters were compared to those of neurons derived from healthy control iPSCs to identify mutation-specific alterations.
Results:
Whole-cell patch-clamp recordings were performed on 10 weeks post-differentiation to evaluate electrophysiological properties. GABAergic neurons derived from ATP1A3-mutant iPSCs exhibited significantly reduced Na⁺/K⁺-ATPase activity, as evidenced by decreased ouabain-sensitive pump currents. Electrophysiological analyses further revealed a more depolarized resting membrane potential, broader action potential half-widths in mutant neurons compared to controls.
Conclusions:
These findings indicate that GABAergic neurons derived from ATP1A3-mutant iPSCs exhibit disrupted ion homeostasis and altered membrane excitability, contributing to the neuronal dysfunction observed in ATP1A3-related disorders. Further validation using cerebral organoids or in vivo models is warranted to confirm and extend these observations.
Funding: The authors declare no conflict of interest.