DYRK1A up-regulation specifically impairs a presynaptic form of long-term potentiation

Chromosome 21 DYRK1A kinase has long been associated with a variety of psychiatric diseases including Down Syndrome. We previously showed that Dyrk1A interacts with SWI/SNF (SWItch/Sucrose Non-Fermentable) nucleosome remodeling complex inducing expression changes of genes encoding key neuronal proteins. However, the functional impact of this kinase at the synapse level remains unclear. We studied a mouse model that incorporated the YAC 152F7 (570 kb) encoding six chromosome 21 genes including DYRK1A. We found that DYRK1A Interacts with the key chromatin remodelers EP300 and CREBBP. Moreover, we observed changes in the transcriptional levels of genes encoding presynaptic proteins involved in glutamate vesicle exocytosis, namely Rims1, Munc13-1, Syn2, Rab3A. This result prompted us to investigate the two main forms of long-term potentiation (LTP) required for learning and memory: the (N-methyl d-aspartate) receptor-dependent postsynaptic form versus the glutamate release-dependent presynaptic form. Interestingly, extracellular electrophysiological recordings in hippocampal slices of the YAC mouse line revealed that only the presynaptic forms of plasticity were impacted, leaving the post-synaptic form of plasticity intact. T o refine our findings, we used a mouse BAC 189N3 (152 kb) line that only triplicate the gene Dyrk1A. Again, we found that this presynaptic form of LTP is also impaired in this mouse line. This result demonstrates that abnormal up-regulation of Dyrk1A alone is sufficient to inhibit specifically the presynaptic forms of LTP. Altogether, our results suggest that impairment of DYRK1A gene dosage may impact memory precision, and therefore reinforce our mechanistic understanding of the cognitive impairment detected in this mouse model.