Abstract Alzheimer’s disease symptoms include gradual cognitive decline and memory loss that is correlated with progressive loss of neuronal connections due to an imbalance of excitatory and inhibitory synaptic functions. These have been shown in various rodent models but direct measurements of excitatory–inhibitory changes have yet to be performed in human neurons. Therefore, our project aims to construct a human-induced pluripotent stem cell co-culture model representing important brain circuitry which captures synaptic dysfunction. Familial Alzheimer’s disease patient induced pluripotent stem cells carrying mutant APP V717I and their isogenic controls were differentiated into cortical glutamatergic neurons and astrocytes using dual-SMAD inhibition followed by in vitro corticogenesis. Building upon this, we differentiated inhibitory interneurons expressing parvalbumin and somatostatin via ventral patterning with sonic hedgehog activation. Then, we co-cultured these cells with differentiated cortical neurons and astrocytes. The properties of the co-culture model were validated using immunohistochemistry, confocal microscopy combined with electrophysiological whole-cell recordings. Confocal microscopy validated the presence of excitatory cortical neurons, astrocytes, and two inhibitory interneuron types, parvalbumin and somatostatin expressing interneurons within the co-culture. Whole-cell recordings revealed intrinsic membrane properties from individual excitatory and inhibitory neurons in this co-culture from day 70 onwards. Spontaneous synaptic activity recorded from the APP V717I-induced pluripotent stem cell model showed synaptic hyperexcitability correlated with altered morphological changes, which was expected in contrast to the isogenic control co-culture. Our novel co-culture model, including astrocytes, excitatory and inhibitory neurons, represents a strong model of brain circuitry in Alzheimer’s disease. These models will enable investigation of Alzheimer’s disease causative mutations on neuronal connectivity in human neurons allowing for confirmation of network dysfunction in Alzheimer’s disease in human neurons. It also has the potential of becoming a valuable preclinical tool to screen novel targeted therapies. This is a methods paper validating a human-induced pluripotent stem cell-derived excitatory–inhibitory neuron–astrocyte co culture with electrophysiological readouts and immunostaining, focusing on Alzheimer’s disease relevant network physiology.
Li et al. (Thu,) studied this question.