Fig. 3: Meg3-ex10 loss-of-function resulted in delayed social fear extinction.

A, F Schematic timeline for behavioral testing and microinfusion of antisense LNA GapmeRs targeting Meg3-ex10. Antisense LNA GapmeRs were bilaterally microinfused into the septum (0.05 nmol); extinction training was performed 72 h thereafter. B Meg3-ex10 knockdown induced 24 h after acquisition and 72 h prior to social fear extinction did neither affect social fear expression (*p < 0.005 SFC+ control/knockdown vs. SFC− control/ knockdown, respectively) nor the dynamics of social fear extinction (p = 0.9998 SFC+ control vs. SFC+ knockdown). n(SFC− control/SFC− knockdown) = 21/19, n(SFC+ control/SFC+ knockdown) = 33/34. C Subgroups were subjected to either short-term (on day 6) or long-term (on day 26) recall. Day 6: n(SFC− control/SFC− knockdown) = 4/2, n(SFC+ control/SFC+ knockdown) = 10/7; Day 26: n(SFC− control/SFC− knockdown) = 6/6, n(SFC+ control/SFC+ knockdown) = 9/14. D Mice were sacrificed at 90 min after the last behavioral assessment to investigate septal Meg3-ex10 expression levels, or to visualize the infusion site and GapmeR distribution within the septum (not shown). E Distribution of FAM-labeled antisense LNA GapmeRs within the septum 23 days after microinfusion. G Social fear memory consolidation was not impaired by Meg3-ex10 knockdown, as similarly low investigation levels of the first social stimulus during social fear extinction training were found in SFC+ control and SFC+ knockdown mice. However, in SFC+ knockdown mice social fear extinction was delayed by Meg-ex10 knockdown, as the significant difference in investigation times compared to SFC− mice remained until exposure to the fourth social stimulus (*p < 0.05 SFC+ control vs. SFC− control, # p < 0.05 SFC+ knockdown vs. SFC− knockdown, two-way ANOVA, Bonferroni multiple comparison tests). n = 5–7. H Meg3-ex10 knockdown induced before the acquisition training was either verified by controlling the infusion site and the GapmeR distribution (not shown) or by measuring relative Meg3-ex10 levels at 90 min after the social fear extinction training. I Meg3-ex10 knockdown 48 h prior to social fear acquisition did not affect social fear acquisition, as SFC+ control and knockdown animals required a similar number of pairings between the conditioned stimulus (CS, unknown conspecific) and an unconditioned stimulus (US, 0.7 mA foot shock) to acquire social fear during social fear acquisition. Data represent mean fold change + SEM normalized to corresponding control group or mean investigation time ± SEM during social fear extinction or recall.