Fig. 4: The NEDD8 inhibitor MLN4924 impairs LTP in rat hippocampal slices and degradation of DNMT3A1 upon LTP induction is absent in GluN2A knock out mice.

a Schematic presentation of LTP induction by high-frequency stimulation in acute CA1 hippocampal slices. Only the potentiated CA1 region was dissected from individual hippocampal slices 6 h following LTP recordings. Representative traces from recordings at the time points indicated under control and treatment conditions. b, c DNMT3A1 levels are reduced 6 h after LTP induction and neddylation inhibition prevented the degradation of Dnmt3A1. β-Actin was used as an internal control for normalization. Two-way ANOVA followed by Bonferroni’s post hoc test. **p < 0.01, *p < 0.05. d Averaged fEPSP slopes of the last hour following LTP induction showed significantly reduced LTP in MLN4924 (50 nM) treated slices in comparison to slices treated by DMSO. Mann–Whitney U-Test ***p < 0.001. e Application of MLN4924 for 6 h induces significantly impaired LTP as compared to controls. *p < 0.05 and **p < 0.01. f Baseline recordings revealed no alterations. g, h GluN2A knockout (KO) mice show higher DNMT3A1 protein levels in the CA1 region of the hippocampus compared to the age-matched wild type (WT) control mice. unpaired Student’s t-test **p < 0.01. i–l Quantitative immunoblotting either from the CA1 of WT (i, j) or GluN2A KO (k, l) mice revealed no reduction in the GluN2A KO mice following 3 h of LTP recordings unlike reduction seen in the WT control mice tissue. Unpaired Student’s t-test. *p < 0.05, n.s. not significant. Error bars present S.E.M. Sample numbers for each experimental group indicate potentiated pooled CA1 slices from at least three different recordings or mice used per group.