In Vitro Differentiated Human Stem Cell-Derived Neurons Reproduce Synaptic Synchronicity Arising during Neurodevelopment

Abstract

Summary Neurons differentiated from induced pluripotent stem cells (iPSCs) typically show regular spiking and synaptic activity but lack more complex network activity critical for brain development, such as periodic depolarizations including simultaneous involvement of glutamatergic and GABAergic neurotransmission. We generated human iPSC-derived neurons exhibiting spontaneous oscillatory activity after cultivation of up to 6 months, which resembles early oscillations observed in rodent neurons. This behavior was found in neurons generated using a more “native” embryoid body protocol, in contrast to a “fast” protocol based on NGN2 overexpression. A comparison with published data indicates that EB-derived neurons reach the maturity of neurons of the third trimester and NGN2-derived neurons of the second trimester of human gestation. Co-culturing NGN2-derived neurons with astrocytes only led to a partial compensation and did not reliably induce complex network activity. Our data will help selection of the appropriate iPSC differentiation assay to address specific questions related to neurodevelopmental disorders.

Induction of Dopaminergic Neurons for Neuronal Subtype-Specific Modeling of Psychiatric Disease Risk

“…This likely reflects the immature nature of iDANs compared to adult MDNs, as I h currents do not typically develop until the early post-natal period 76 in rodents. iDAN cell capacitance, another measure of maturity, was 20 (±8) pF, comparable to values recorded in iGLUT neurons (22 ±1 pF) 77 and human second trimester neurons (range of 18.5 ±2.5 pF to 24.8 ±3.5 pF) 78 . Likewise, competitive gene set testing also indicated global gene expression patterns consistent with an early neurodevelopmental, midbrain dopaminergic neuron phenotype.…”

“…Likewise, competitive gene set testing also indicated global gene expression patterns consistent with an early neurodevelopmental, midbrain dopaminergic neuron phenotype. This is unsurprising, given previous reports that other types of hiPSCs-derived neurons most closely resemble human fetal neurons 79,80 , specifically those at 16-24 post-conception weeks 77 . This makes iDANs more suitable for studies of mechanisms related to psychiatric disease risk and onset, rather than phenotypes associated with late-stage disease.…”

The iPSC perspective on schizophrenia

“…Inhibitory activity has been reported in astrocyte-enriched cultures containing a mixture of excitatory and inhibitory neurons [25,126,127]. Impressively, oscillatory patterns typical of late stages of human gestation have been modeled in long-term cultures of iPSC-derived neurons [21,128]. Delta frequency oscillations (2-3 Hz) have been detected in cortical organoids after 4 months of culturing, and the emergence of high-frequency gamma (100-400 Hz) activity has been observed after 6 months of maturation, coinciding with the development of GABAergic neurons [21].…”

“…Delta frequency oscillations (2-3 Hz) have been detected in cortical organoids after 4 months of culturing, and the emergence of high-frequency gamma (100-400 Hz) activity has been observed after 6 months of maturation, coinciding with the development of GABAergic neurons [21]. The generation of the oscillatory events has been shown to involve both AMPA and NMDA receptor input, whereas GABAergic input is required to maintain the oscillatory activity [128]. Neuronal type…”

Modeling neurodevelopment in a dish with pluripotent stem cells

“…To overcome this problem, the overexpression of master regulator genes, such as NEUROG2 , in PSCs can shortcut the neural differentiation processes, and electrophysiologically active neurons can be obtained in a few weeks (Y. Zhang et al., 2013). However, it is still controversial whether this rapid gene‐based neuronal induction from PSCs can fully recapitulate all the aspects of mature neurons, because some features of postnatal mature neurons are observed in native directed differentiation that occurs over 6 months, but not in the gene‐based differentiation method (Rosa et al., 2020).…”