FIGURE SUMMARY
Title

adgrl3.1-deficient zebrafish show noradrenaline-mediated externalizing behaviors, and altered expression of externalizing disorder-candidate genes, suggesting functional targets for treatment

Authors
Fontana, B.D., Reichmann, F., Tilley, C.A., Lavlou, P., Shkumatava, A., Alnassar, N., Hillman, C., Karlsson, K.Æ., Norton, W.H.J., Parker, M.O.
Source
Full text @ Transl Psychiatry

adgrl3.1−/− shows attention deficits, impulsivity, and increased risk-taking.

A Flow-chart summarizing the 5-CSRTT process. During the 5-CSRTT, fish were required to swim toward one of five spatially distinct LEDs when illuminated. Approaches to the illuminated light were ‘correct’ and the proportion of correct trials was a measure of attention. Prior to illumination, there was a variable-time (mean 5-s) inter-trial interval, and responses during this interval were punished with subsequent non-reinforcement. Responses during this inter-trial interval (anticipatory or premature responses) were used as a measure of impulse control. B No significant effects were found after two-way RM ANOVA for the acquisition during the Stage IV of the 5-CSRTT (Day*Group effect—F(8, 136) = 0.50; p = 0.95; Group effect—F(1, 17) = 0.69; p = 0.41; Day effect—F(4, 247) = 0.45; p = 0.77). C One-way ANOVA yielded a significant effect for accuracy (F(2,25) = 5.80; p** = 0.0085), D anticipatory responses (F(2,25) = 14.17; p**** < 0.0001) with no effects for (E) omissions (F(2,25) = 1.80; p = 0.18). Tukey’s post-hoc analysis was used to characterize significant differences (p** < 0.005 and p**** < 0.0001; n = 9–10). F Risk-taking behavior is defined as time spent close to the novel object. A significant ANOVA effect was observed for time spent close to the object (F(2,32) = 8.35; p** = 0.0012) where adgrl3.1−/− spent more time close to the object (p* = 0.0148), an effect that was 750 significantly decreased by atomoxetine in adgrl3.1−/− (p** = 0.015; n = 12–13). The data is represented as mean ± S.E.M.

adgrl3.1−/− zebrafish show increased locomotion after 3 days of habituation.

A Significant two-way RM ANOVA effect for habituation (F(1.995, 135.7) = 3.84; p* = 0.024) was observed for distance traveled, with no significant effects for interaction between factors (genotype*habituation; F (2, 136) = 1.66; p = 0.19) nor genotype (F (1, 68) = 1.40; p = 0.24). For immobility, a significant effect of genotype*habituation (F (2, 136) = 3.66; p* = 0.03), habituation (F (1.998, 81.51) = 5.92; p* = 0.013), and genotype (F (1, 68) = 10.23; p** = 0.002) was found. Post-hoc analyses showed that adgrl3.1–/– has increased immobility during the first day of habituation compared to WT (p* = 0.018). adgrl3.1−/− also showed a habituation to the novel environment by showing a decrease in their immobility during the second day (p* = 0.025) and third day (p* = 0.03) compared to the first day of habituation. B Representative tracking of a WT vs. adgrl3.1−/− vs. adgrl3.1−/− + ATO animal during the test day. C A significant ANOVA effect was found for distance traveled (F(2,48) = 5.44; p** = 0.007) during the test day. Briefly, distance traveled was increased for adgrl3.1−/− compared to WT animals (p** = 0.005) with no effect for adgrl3.1−/− compared to adgrl3.1−/− + ATO (p = 0.14). No effect for immobility was observed (p = 0.54). The data is represented as mean ± S.E.M.

RNA-seq summary data.

A Principal component analysis plot of the top 200 most variable genes after differential expression analysis. n = 4 brains/group. B Venn diagram showing the overlap of differentially expressed genes (DEGs) between WT zebrafish, adgrl3.1−/− and adgrl3.1−/− treated with atomoxetine. C Heatmap of DEGs (lowest adjusted p value (padj) < 0.05 and LFC > |2 | ) between WT and adgrl3.1−/−. D Volcano plot displaying DEGs between WT and adgrl3.1−/−. DEGs with padj are highlighted. n = 4 per group. E Heatmap of DEGs (padj < 0.05 and LFC > |2 | ) between WT and adgrl3.1−/− treated with atomoxetine. F Volcano plot displaying DEGs between WT and adgrl3.1−/− treated with atomoxetine. DEGs with padj are highlighted. n = 4 per group. G Heatmap of DEGs (padj < 0.05 and LFC > |2 | ) between adgrl3.1−/− and adgrl3.1−/− treated with atomoxetine. H Volcano plot displaying DEGs between adgrl3.1−/− and adgrl3.1−/− treated with atomoxetine. DEGs with padj are highlighted. n = 4 per group.

Acknowledgments
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