Electrophysiological measures from human iPSC-derived neurons are associated with schizophrenia clinical status and predict individual cognitive performance

Fig. 1.. Description of experimental lines and experiment overview. (A) PRS of neurotypical controls and individuals with SCZ included in this study (CON, −14.829 ± 1.535, n = 15; SCZ, −8.375 ± 1.1736, n = 13; P = 1.78E-12). (B) Pluripotency of reprogrammed lines was verified by identification of NANOG+, SOX2+, OCT3/4+, and TRA-1-60+ colonies colocalized with DAPI using immunocytochemistry. (C) qPCR quantification of stem cell markers SOX2 (CON, 1.152 ± 0.151; SCZ, 1.162 ± 0.133; P = 0.96, n = 35 from 28 genomes) and NANOG (CON, 1.133 ± 0.062; SCZ, 1.222 ± 0.063; P = 0.32, n = 35 from 28 genomes), normalized to embryonic stem cell line H1. (D) hiPSCs were differentiated into neurons in multiple batches. (E) Representative images of induced pluripotent stem cell colony (bright field), EB (bright field), immunofluorescence of neural rosettes at 2 d, DAPI (blue), SOX2 (green), PAX6 (red); immunofluorescence of neurons at DIV56, DAPI (blue), MAP2 (green), NeuN (red); immunofluorescence of neurons showing synaptic puncta at DIV70, Tuj1 (blue), PSD95 (green), SYNAPSIN1 (red), NeuN (white). (F) Quantification of the proportion of NeuN+ cells to the number of DAPI-stained nuclei shows no…

Fig. 2.. Electrophysiological differences between CON and SCZ lines. (A) Table of electrophysiological phenotypes observed between CON and SCZ lines. (B) Representative traces showing Na+ currents (asterisks and Insets) in response to a voltage-ramp protocol (above). (C) Summary data showing significantly more Na+ currents in SCZ neurons versus CON neurons across all genomes (SCZ effect, 0.093, P = 0.038, n = 1,074 from 28 genomes). (D) Representative traces of sIPSCs recorded from CON and SCZ neurons at 0 mV. (E) Summary data showing significantly increased sIPSC frequency in SCZ neurons versus CON neurons across all genomes (SCZ effect, 0.097, P = 1.14E-6, n = 903 from 28 genomes).

Fig. 3.. Altered Na+ channel activation and inactivation in six SCZ compared with seven CON. (A) Representative Na+ current traces in response to voltage steps (−100 to +20 mV). (B) Voltage dependence of steady-state activation of Na+ channels in SCZ and CON neurons. (C) Summary data showing a significantly hyperpolarized shift in the activation of Na+ channels in SCZ neurons versus CON neurons (CON, V1/2 = −39.2 ± 0.6 mV; SCZ, V1/2 = −41.1 ± 0.7 mV; Delta = 1.9 mV, *P = 0.039, n = 173 from 13 genomes). (D) Representative Na+ current traces in response to a steady-state inactivation protocol (initial voltage steps from −130 to 20 mV; test voltage steps, −20 mV) to measure channel inactivation. (E) Voltage dependence of steady-state inactivation of Na+ channels in SCZ and CON neurons. (F) Summary data showing a significantly hyperpolarized shift in the inactivation of Na+ channels in SCZ neurons versus CON neurons (CON, V1/2 = −58.1 ± 0.6 mV; SCZ, V1/2 = −61.8 ± 0.7 mV; Delta = 3.7 mV, ****P < 0.0001, adjusted P < 0.0035, n = 162 from 13 genomes). All data represented as mean ± standard error of the mean.

Fig. 4.. Reduced inactivation in SCZ is reflected in the AP-ISI in 13 SCZ compared with 15 CON. (A) Representative Na+ currents in response to four consecutive voltage steps from a holding potential of −90 to −30 mV in an SCZ (red) and CON (black) neuron. Capacitance transients are blanked out. (B) Group data of LTI. (C) Summary LTI of Na+ currents for each voltage step normalized by the currents generated by the first voltage step showing reduced LTI in SCZ compared with CON neurons (CON P2/P1 = 0.59 ± 0.02; SCZ P2/P1 = 0.66 ± 0.024, post hoc P = 0.024; CON P3/P1 = 0.50 ± 0.02; SCZ P3/P1 = 0.57 ± 0.02, *P = 0.023, post hoc P = 0.023; CON P4/P1 = 0.46 ± 0.03; SCZ P4/P1 = 0.54 ± 0.021, post hoc P = 0.021; mixed-effects ANOVA P < 0.0001, n = 148 from 11 genomes). (D) Example AP trains generated in SCZ and CON neurons. (E) Group data showing the AP-ISI for the second (CON 0.086 ± 0.004 s, SCZ 0.071 ± 0.003 s, **P = 0.0018, n = 297 from 28 genomes), last (CON 0.102 ± 0.004 s, SCZ 0.086 ± 0.004 s, **P = 0.002, n = 297 from 28 genomes), and minimum AP-ISI (CON 0.074 ± 0.003 s, SCZ = 0.060 ± 0.002 s, ***P = 0.0006, n = 297 from 28 genomes), but not the first AP-ISI (CON 0.077 ± 0.003 s, SCZ =…

Fig. 5.. Association between two electrophysiological phenotypes and selected clinical and cognitive phenotypes. (A) Correlation results in 13 SCZ. Shown are all eight cognitive phenotypes tested, along with the clinical phenotypes with unadjusted P < 0.05 with either electrophysiological measure. ***Adjusted P = 0.00014. Results for SCZ and CON, including the adjusted P values, for seven electrophysiological measures and all clinical and cognitive phenotypes tested are shown in Datasets S3 and S4. (WAIS denotes Weschler Adult Intelligence Scale). (B) Relationships between the number of Na+ peaks and a positive symptom, hallucination (CON, n = 12, P, not calculated; SCZ, n = 12, R = 0.77, P = 0.0033). (C) Relationships between sEPSC amplitude and a negative symptom, emotional withdrawal (CON, n = 12, R = −0.034, P = 0.92; SCZ, n = 12, R = 0.73, P = 0.0071). (D) Relationships between sEPSC amplitude and WCST performance (CON, n = 15, R = 0.16, P = 0.58; SCZ, n = 11, R = −0.93, P = 2.94E-05).