Fig. 4: hiPSC-derived CNs from ADHD patients show altered glutamatergic development.

A Extracellular glutamate assay revealed a significant increase in concentration in HC CNs during maturation (n = 4). B No significant increase in extracellular glutamate was observed in ADHD patient CNs (n = 4). C Expression of glutamatergic signalling genes was investigated in mature 12-week-old CNs from HC (n = 5) and ADHD patients (n = 7) using RT-qPCR. vGLUT2 transcription was found significantly decreased in ADHD patient CNs by ~50%. D Expression of glutamate transport genes was also investigated. No significant differences in EAAT1 or SNAT7 transcription were found. However, a significant reduction in EAAT2 transcription was found in ADHD patient CNs. To assess potentially altered neurodevelopment, E PAX6 and F vGLUT2 transcription was determined over time in HC (n = 4) and ADHD patients (n = 4). There were no significant differences in PAX6 transcription over time. However, vGLUT2 transcription showed a distinct course, with significantly reduced vGLUT2 gene expression found at 4 and 12 weeks. Data was analysed using repeated measures one-way ANOVA A, B, independent t-tests C, D and two-way ANOVA (E, F). CNs cortical neurons, HC healthy controls. *p < 0.05, **p < 0.01.