Fig. 6 |. Minocycline inhibits synapse engulfment in vitro and decreases SZ risk in EHRs.
a, Quantification of pHrodo (red)-labeled SYN uptake in iMG cells during live imaging sessions of 5.5 h. iMG cultures (n = 8 models with iMG derived from 8 patients and SYNs from 2 patients) were pretreated for 30 min with VEH or minocycline at a concentration of 1 μ M, 10 μ M, or 60 μ M. Nine images (20×) per well were automatically acquired every hour; the means were then extracted and analyzed using a two-way repeated ANOVA. There was a significant interaction between the effects of time and group on the phagocytic index (F(30, 270) = 17.0; P < 0.0001). Šidák’s multiple comparison tests gave significant adjusted P values for all comparisons at the last time point (5.5 h); P values ranged from < 0.0001 to 0.008. b, Representative images from a displaying pHrodo+ uptake at 5.5 h in different conditions. Scale bar, 25 μ m. c, Quantification of spine density (spines per 10-μm dendrite) in a neural line derived from an HC and treated with 60 μm minocycline as indicated (n = 80 randomly selected dendrites examined in the SZ group and n = 100 randomly selected dendrites examined in the HC group). Welch-corrected t test: t(148) = 0.35, P = 0.72 (two-sided). Quantification of spine density in co-cultures (neurons and iMG cells) derived from an HC line and treated with 60 μm minocycline or VEH as indicated (n = 48 randomly selected dendrites examines in the VEH group and n = 51 in the minocycline group). Welch-corrected t test): t(87.2) = 2.66, P = 0.010. Data are normalized to the VEH group in the graph; the mean number of spines per 10 μm was 3.2 (s.e.m. = 0.34) among untreated cultures and 4.7 (s.e.m. = 0.48) in minocycline-treated cultures. d, Representative images of phalloidin-stained high-magnification confocal images of dendritic spines (indicated by the arrowheads) in VEH- and minocycline-treated cocultures in the experiments described in c. e, Time to diagnosis in individuals exposed to monocycline or doxycycline for at least 90 d or exposed for fewer than 90 d (log-rank χ2(1 d.f.) = 5.66; P = 0.017). Cumulative hazard at 10 years was 0.0185 (95% CI 0.0110–0.0312) in the exposed group, and 0.0279 (95% CI 0.0225–0.0346) in the unexposed group. Likewise, in a Cox (proportional hazards) regression model, monocycline or doxycycline exposure for at least 90 d was associated with decreased risk of incident psychosis (HR 0.58, 95% CI 0.39–0.88). Results were unchanged after excluding 672 individuals exposed to isotretinoin. The error bars in panels a and c represent s.e.m. All P values are two-sided; mean ±s.e.m. values are indicated in a and c.