Neuronal network dysfunction in a model for Kleefstra syndrome mediated by enhanced NMDAR signaling

Abstract

Kleefstra syndrome (KS) is a neurodevelopmental disorder caused by mutations in the histone methyltransferase EHMT1. To study the impact of decreased EHMT1 function in human cells, we generated excitatory cortical neurons from induced pluripotent stem (iPS) cells derived from KS patients. Neuronal networks of patient-derived cells exhibit network bursting with a reduced rate, longer duration, and increased temporal irregularity compared to control networks. We show that these changes are mediated by upregulation of NMDA receptor (NMDAR) subunit 1 correlating with reduced deposition of the repressive H3K9me2 mark, the catalytic product of EHMT1, at the GRIN1 promoter. In mice EHMT1 deficiency leads to similar neuronal network impairments with increased NMDAR function. Finally, we rescue the KS patient-derived neuronal network phenotypes by pharmacological inhibition of NMDARs. Summarized, we demonstrate a direct link between EHMT1 deficiency and NMDAR hyperfunction in human neurons, providing a potential basis for more targeted therapeutic approaches for KS.

Variant-specific changes in persistent or resurgent Na+current inSCN8A-EIEE13 iPSC-derived neurons

“…These differences are similar to changes in network bursts observed following the administration of chemoconvulsants such as bicuculline, pentylentetrazole, and 4aminopyridine (Odawara et al, 2016). A recent publication investigating Kleefstra syndrome using iNeurons on MEAs identified disease specific alterations using similar outcomes measures, including burst duration, % of spikes out of bursts, and inter-burst-interval coefficient of variation (Frega et al, 2019). Importantly, EIEE13 patient cultures demonstrated "burst of bursts" events with high-frequency network bursting that did not occur in controls.…”

Cadherin-13 is a critical regulator of GABAergic modulation in human stem cell derived neuronal networks

“…All recordings were performed using the 24-well MEA system (Multichannel Systems, MCS GmbH, Reutlingen, Germany) as described before 75,77 . Spontaneous electrophysiological activity of E/I networks was recorded for 10 min at 37°C and constant flow of humidified gas (5% CO2 and 95% O2).…”

“…All Oct4, Sox2, Klf4, and cMyc. Generated clones (at least two per patient line) were selected and tested for pluripotency and genomic integrity based on single nucleotide polymorphism (SNP) arrays 75 . HiPSCs were cultured on Matrigel (Corning, #356237) in E8 flex (Thermo Fisher Scientific) supplemented with primocin (0.1 µg/ml, Invivogen) and low puromycin (0.5 µg/ml, to select for rtTA positive cells) and G418 concentrations (50 µg/ml, to select for Ngn2 or Ascl1 positive cells) at 37˚C/5% CO2.…”

“…The rodent astrocytes presented in this study were harvested embryonic (E18) rat brains (Wistar Wu) as previously described 75,77,86 . All experiments on animals were carried out in accordance with the approved animal care and use guidelines of the Animal Care Committee, Radboud University Medical Centre, the Netherlands, (RU-DEC-2011-021, protocol number: 77073).…”

Gene functional networks and autism spectrum characteristics in young people with intellectual disability

“…Our approach of allocating genes to network groups is based on integration of multiple literature sources, each limited by existing functional data. Boundaries between networks are difficult to define; for example, chromatin-associated genes will have downstream effects on synaptogenesis, neurotransmission and plasticity by regulating expression of synaptic-relevant targets (27)(28)(29). We included components of the Wnt signalling pathway (DDX3X and CTNNB1) in the "Synaptic" group, because of emerging evidence that Wnt signalling directly "tunes" neurotransmitter release and modulates synaptic plasticity (30).…”