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The amino acid glutamate opens cation permeable ion channels, the iGlu receptors. These ion channels are abundantly expressed in the mammalian brain where glutamate is the main excitatory neurotransmitter. The neurotransmitters and their receptors are being increasingly detected in the cells of immune system. Here we examined the expression of the 18 known subunits of the iGlu receptors families; α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate, N-methyl-d-aspartate (NMDA) and delta in human peripheral blood mononuclear cells (PBMCs). We compared the expression of the subunits between four groups: men, non-pregnant women, healthy pregnant women and depressed pregnant women. Out of 18 subunits of the iGlu receptors, mRNAs for 11 subunits were detected in PBMCs from men and non-pregnant women; AMPA: GluA3, GluA4, kainate: GluK2, GluK4, GluK5, NMDA: GluN1, GluN2C, GluN2D, GluN3A, GluN3B, and delta: GluD1. In the healthy and the depressed pregnant women, in addition, the delta GluD2 subunit was identified. The mRNAs for GluK4, GluK5, GluN2C and GluN2D were expressed at a higher level than other subunits. Gender, pregnancy or depression during pregnancy altered the expression of GluA3, GluK4, GluN2D, GluN3B and GluD1 iGlu subunit mRNAs. The greatest changes recorded were the lower GluA3 and GluK4 mRNA levels in pregnant women and the higher GluN2D mRNA level in healthy but not in depressed pregnant women as compared to non-pregnant individuals. Using subunit specific antibodies, the GluK4, GluK5, GluN1, GluN2C and GluN2D subunit proteins were identified in the PBMCs. The results show expression of specific iGlu receptor subunit in the PBMCs and support the idea of physiology-driven changes of iGlu receptors subtypes in the immune cells.

GABAA receptors are pentameric chloride ion channels that are opened by GABA. We have screened a cell line derived from human glioblastoma, U3047MG, for expression of GABAA receptor subunit isoforms and formation of functional ion channels. We identified GABAA receptors subunit α2, α3, α5, β1, β2, β3, δ, γ3, π, and θ mRNAs in the U3047MG cell line. Whole-cell GABA-activated currents were recorded and the half-maximal concentration (EC₅₀) for the GABA-activated current was 36 μM. The currents were activated by THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and enhanced by the benzodiazepine diazepam (1 μM) and the general anesthetics etomidate and propofol (50 μM). In line with the expressed GABAA receptors containing at least the α3β3θ subunits, the receptors were highly sensitive to etomidate (EC₅₀=55 nM). Immunocytochemistry identified expression of the α3 and β3 subunit proteins. Our results show that the GABAA receptors in the glial cell line are functional and are modulated by classical GABAA receptor drugs. We propose that the U3047MG cell line may be used as a model system to study GABAA receptors function and pharmacology in glial cells.

We generated human iPS derived neural stem cells and differentiated cells from healthy control individuals and an individual with autism spectrum disorder carrying bi-allelic NRXN1-alpha deletion. We investigated the expression of NRXN1-alpha during neural induction and neural differentiation and observed a pivotal role for NRXN1-alpha during early neural induction and neuronal differentiation. Single cell RNA-seq pinpointed neural stem cells carrying NRXN1-alpha deletion shifting towards radial glia-like cell identity and revealed higher proportion of differentiated astroglia. Furthermore, neuronal cells carrying NRXN1-alpha deletion were identified as immature by single cell RNA-seq analysis, displayed significant depression in calcium signaling activity and presented impaired maturation action potential profile in neurons investigated with electrophysiology. Our observations propose NRXN1-alpha plays an important role for the efficient establishment of neural stem cells, in neuronal differentiation and in maturation of functional excitatory neuronal cells.