ANK2 loss-of-function variants are associated with epilepsy, and lead to impaired axon initial segment plasticity and hyperactive network activity in hiPSC-derived neuronal networks

• Published in: Human molecular genetics Vol. 32; no. 14; pp. 2373 - 2385
• Main Authors: Teunissen, Maria W A, Lewerissa, Elly, van Hugte, Eline J H, Wang, Shan, Ockeloen, Charlotte W, Koolen, David A, Pfundt, Rolph, Marcelis, Carlo L M, Brilstra, Eva, Howe, Jennifer L, Scherer, Stephen W, Le Guillou, Xavier, Bilan, Frédéric, Primiano, Michelle, Roohi, Jasmin, Piton, Amelie, de Saint Martin, Anne, Baer, Sarah, Seiffert, Simone, Platzer, Konrad, Jamra, Rami Abou, Syrbe, Steffen, Doering, Jan H, Lakhani, Shenela, Nangia, Srishti, Gilissen, Christian, Vermeulen, R Jeroen, Rouhl, Rob P W, Brunner, Han G, Willemsen, Marjolein H, Nadif Kasri, Nael
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 04.07.2023; Oxford University Press (OUP)
• Subjects: Ankyrins - genetics; Ankyrins - metabolism; Axon Initial Segment - metabolism; Epilepsy - genetics; Epilepsy - metabolism; Genetics; Human genetics; Human health and pathology; Humans; Induced Pluripotent Stem Cells; Life Sciences; Neurons - metabolism; Neurons and Cognition; Original
• ISSN: 0964-6906; 1460-2083; 1460-2083
• DOI: 10.1093/hmg/ddad081

Abstract Purpose To characterize a novel neurodevelopmental syndrome due to loss-of-function (LoF) variants in Ankyrin 2 (ANK2), and to explore the effects on neuronal network dynamics and homeostatic plasticity in human-induced pluripotent stem cell-derived neurons. Methods We collected clinical and molecular data of 12 individuals with heterozygous de novo LoF variants in ANK2. We generated a heterozygous LoF allele of ANK2 using CRISPR/Cas9 in human-induced pluripotent stem cells (hiPSCs). HiPSCs were differentiated into excitatory neurons, and we measured their spontaneous electrophysiological responses using micro-electrode arrays (MEAs). We also characterized their somatodendritic morphology and axon initial segment (AIS) structure and plasticity. Results We found a broad neurodevelopmental disorder (NDD), comprising intellectual disability, autism spectrum disorders and early onset epilepsy. Using MEAs, we found that hiPSC-derived neurons with heterozygous LoF of ANK2 show a hyperactive and desynchronized neuronal network. ANK2-deficient neurons also showed increased somatodendritic structures and altered AIS structure of which its plasticity is impaired upon activity-dependent modulation. Conclusions Phenotypic characterization of patients with de novo ANK2 LoF variants defines a novel NDD with early onset epilepsy. Our functional in vitro data of ANK2-deficient human neurons show a specific neuronal phenotype in which reduced ANKB expression leads to hyperactive and desynchronized neuronal network activity, increased somatodendritic complexity and AIS structure and impaired activity-dependent plasticity of the AIS.