Fig 2: GABA supplementation rescues cognitive impairment and immune response in female Cntnap4+/− mice. A) The mRNA expression levels of Gad1 and Gad2 in hippocampi of wild‐type (WT) and Cntnap4+/− mice. n = 3 per group. B,C) Representative blots and quantification showing GAD1 and GAD2 expression in hippocampi of WT and Cntnap4+/− mice. n = 6 per group. D,E) Immunofluorescence staining and quantification of Iba1 colocalization with GABA in hippocampi of WT and Cntnap4+/− mice. n = 6−8. Scale bars, 40 µm. Magnified images are shown in the right column. Scale bars, 10 µm. F) Experimental design for GABA administration in Cntnap4+/− mice. G) The escape latency over a 5‐day training course. In probe tests, mice were analyzed for the H) escape latency and I) time spent in the target zone. n = 8−9. J) Representative traces of GABA receptor‐mediated sIPSCs. All sIPSCs were recorded at a holding potential of −70 mV. K,L) Cumulative frequency plots of sIPSC amplitude, and quantitative analysis of the amplitude of GABA receptor‐mediated sIPSCs. n = 16−18. M,N) Cumulative frequency plots of the inter‐event interval, and quantitative analysis of the frequency of GABA receptor‐mediated sIPSCs. n = 16−18. O) Representative traces of input‐output stimulus intensities. P) Input–output relations generated by stimulating the SCs and recording in the CA1 stratum radiatum. n = 12−15. Q,R) Effects of GABA treatment in Cntnap4+/− mice on the LTP at the SC‐CA1 synapses. The images show representative traces of fEPSP recordings of responses before and 50 min after high‐frequency stimulation (HFS; arrow). S) Quantitative analysis of data in R. The level of fEPSP potentiation was determined as a mean of 0−3 min and 50−60 min after high‐frequency stimulation. n = 12−14. T) Immunofluorescence staining of Iba1‐positive cells in hippocampi of GABA‐treated Cntnap4+/− mice. Scale bars, 40 µm. Magnified images are shown in the right columns. Scale bars, 10 µm. U) Quantification of endpoint voxels, branch length, and volume of Iba1‐positive cells. n = 8−9 per group. V,W) Representative blots and quantification showing TLR4, p‐NF‐κB, NF‐κB, IL‐1β and TNF‐α expression in hippocampi of GABA‐treated Cntnap4+/− mice. n = 3 per group. Results are expressed as the mean ± SEM. ** p < 0.01, * p < 0.05 versus WT; ## p < 0.01, # p < 0.05 versus Cntnap4+/−; && p < 0.01 versus Cntnap4+/− + GABA (1 mg kg−1). Statistical significance was determined using Student's t‐test (for panels (A, C, and E)) and one‐way ANOVA and Tukey's tests for post hoc comparisons (for panels (G–I, L, N, P, S, U, and W)).

Fig 3: The levels of the glutamatergic and GABAergic system proteins in the hippocampi of P301S and 5xFAD mice, and their WT counterparts.A Representative WB for NR1, GAD1, and VGAT of the hippocampi of P301S and WT mice. B The relative abundance of NR1 normalized to β-actin. WT mice (n = 4), P301S mice (n = 4). C The relative abundance of GAD1 normalized to β actin. WT mice (n = 5), P301S mice (n = 5). D The relative abundance of VGAT normalized to β-actin. WT mice (n = 5), P301S mice (n = 5). E Representative WB for NR1, GAD1, and VGAT of the hippocampi of 5xFAD and WT mice. F The relative abundance of NR1 normalized to β-actin. WT mice (n = 4), 5xFAD mice (n = 4). G The relative abundance of GAD1 normalized to β-actin. WT mice (n = 5), 5xFAD mice (n = 5). H The relative abundance of VGAT normalized to β-actin. WT mice (n = 4), 5xFAD mice (n = 4). An unpaired/independent two -tailed test were used, *p ≤ 0.05, **p ≤ 0.01, ns non significant.*p < 0.05; **p < 0.01 vs. WT; ns non significant.

Fig 4: The levels of the glutamatergic and GABAergic system proteins in the cortices of P301S and 5xFAD mice, and their WT counterparts.A Representative WB for NR1, GAD1, and VGAT of the cortices of P301S and WT mice. B The relative abundance of NR1 normalized to β-actin. WT mice (n = 5), P301S mice (n = 5). C The relative abundance of GAD1 normalized to β-actin. WT mice (n = 5), P301S mice (n = 5). D The relative abundance of VGAT normalized to β-actin. WT mice (n = 5), P301S mice (n = 5). E Representative WB for NR1, GAD1, and VGAT of the cortices of 5xFAD and WT mice. F The relative abundance of NR1 normalized to β-actin. WT mice (n = 4), 5xFAD mice (n = 4). G The relative abundance of GAD1 normalized to β-actin. WT mice (n = 5), 5xFAD mice (n = 5). H The relative abundance of VGAT normalized to β actin. WT mice (n = 4), 5xFAD mice (n = 4). An unpaired/independent two-tailed test was used, *p ≤ 0.05, ns non significant.