(A to D) Primary neurons transduced with AAV PHP.eB-Syn-Cxcr3-hemagglutinin–neurexin-1α. Control cultures were not transduced. (A) CXCL11 (CXL; 200 nM) or vehicle applied after a 30-min baseline. Firing rates at 1 min after stimulation (normalized to baseline). Two-way ANOVA: F(1,45) = 8.38, P = 0.0058 for interaction and F(1,45) = 5.83, P = 0.02 for CXCL11. Bonferroni’s test: **P < 0.01 versus vehicle. (B) CXCL11 (200 nM) or vehicle was applied chronically (24 hours) after a 30-min baseline. (C and D) Quantification (C) and images (D) of the presynaptic marker synaptophysin in neurons treated chronically (3 days) with CXCL11 (200 nM) or vehicle. Two-way ANOVA: F(1,50) = 8.85, P = 0.0045 for interaction (firing rate); F(1,50) = 11.73, P = 0.0012 for CXCL11 (firing rate); F(1,36) = 8.65, P = 0.0057 for interaction (area); and F(1,36) = 6.24, P = 0.017 for interaction (counts). Bonferroni’s test: **P < 0.01 and ***P < 0.001 versus vehicle. Scale bar, 50 μm. (E and F) Synaptophysin in the CA1 radiatum of single transgenic controls and ΔNLS mice. One-way ANOVA: F(2,26) = 9.94, P = 0.0006 (E) and F(2,26) = 11.62, P = 0.0002 (F); Dunnett’s post hoc test: ***P < 0.001 versus tetO. (G and H) Recordings in hippocampal slices from controls and ΔNLS mice at 5 to 6 months of age. (G) Basal transmission at increasing stimulus intensities. Mixed-effects model: F(7,344) = 2.10, P = 0.043 for interaction and F(1,50) = 4.19, P = 0.046 for genotype. (H) Paired-pulse facilitation (ratios of fEPSPs to the second pulse as compared to the first pulse). Mixed-effects model: F(6,338) = 2.43, P = 0.026 for interaction and F(1,60) = 7.81, P = 0.007 for genotype. Bonferroni’s test: *P < 0.05. (I and J) fEPSPs in response to the first (I) and second (J) stimulus independent of interval. Student’s t test: ***P < 0.001. (K and L) Primary neurons cocultured with hippocampal Aldh1l1-Cre astrocytes that were transduced with AAV PHP.eB-hGfaABC1D-DIO–hTDP-43–ΔNLS (ΔNLS) or AAV PHP.eB pAAV-FLEX-tdTomato. One-way ANOVA: F(2,25) = 15.93, P < 0.0001 (K). CXCR3 blocker SCH 546738 (12 nM). Dunnett’s test: ***P < 0.001. Student’s t test: ***P = 0.0003.