Fig. 6

Anti-IgLON5 IgG exposure causes imbalance of synaptic homeostasis. A Example traces showing sEPSCs recorded in pyramidal neurons of CA1 for control IgG-injected and IgLON5 IgG-injected mice. B Average sEPSC frequency in the two groups (t = 3.578, df = 39, p = 0.0009, unpaired t-test). C Average sEPSC amplitudes in the two groups (t = 2.052, df = 39, p = 0.0469, unpaired t-test). D Cumulative probability of inter-event internal sEPSCs. Control: n = 20 neurons from four mice; IgLON5-Ab: n = 21 neurons from four mice. E Cumulative probability of the amplitude of sEPSCs. Control: n = 20 neurons from four mice; IgLON5-Ab: n = 21 neurons from four mice. F Current-clamp recordings of anti-IgLON5 IgG and Control-IgG group. G The number of spikes in anti-IgLON5 IgG and Control-IgG group (n = 24–28 neurons, p < 0.0001, two-way ANOVA). H Representative traces recorded in CA1 pyramidal cells from anti-IgLON5 IgG and Control-IgG hippocampal slices following paired-pulse stimulation protocol. I Averaged PPR from anti-IgLON5 IgG and Control-IgG group (n = 19–20 neurons, t = 2.265, df = 37, p = 0.0294, unpaired t-test). J Immunoblot analysis of PSD-95, synaptophysin, and NMDAR1 expression in the hippocampus of IgLON5-IgG- and HC-IgG-treated mice. K–M Quantification of PSD-95, synaptophysin, and NMDAR1 protein levels shows that the levels of these proteins are significantly lower in the IgLON5-IgG-injected group than in the control group. (NMDAR1: t = 2.785, df = 4, p = 0.0496, unpaired t-test; PSD-95: t = 3.163, df = 4, P = 0.0341, unpaired t-test; synaptophysin: t = 2.899, df = 4, p = 0.0441, unpaired t-test). N Immunoblot analysis of PSD-95, synaptophysin, and NMDAR1 expression in cultures exposed to anti-IgLON5 IgG. O–Q Quantification of PSD-95, synaptophysin, and NMDAR1 protein levels showed that the expressions of these proteins are significantly lower in cultures exposed to anti-IgLON5 IgG than in the control group (NMDAR1:t = 5.835, df = 4, p = 0.0043, unpaired t-test; PSD-95: t = 2.828, df = 4, P = 0.0474, unpaired t-test; synaptophysin: t = 4.310, df = 4, p = 0.0126, unpaired t-test). For B–E, n = 20 or 21. For F–G, n = 24–28 per group. For H–I, n = 19 or 20 per group. For J–Q, n = 3 per group. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 vs control IgG group