CONICET | Buscador de Institutos y Recursos Humanos

NMDA Receptors (NMDAR) are glutamatergic receptors involved in synaptic plasticity, learning and memory processes, and also in several neuropathologies. NMDAR are composed by two GluN1 obligatory subunits and two regulatory subunits: GluN2 (A-D) or GluN3 (A-B). In memory related brain structures, like the hippocampus, GluN2A and GluN2B are the most expressed regulatory subunits. Transcription and translation of both subunits are tightly regulated, while GluN2B expression is characteristic of immature synapses, GluN2A is present in mature and stable synapses. However, changes in GluN2A subunit expression has been shown in several synaptopathologies. In order to better understand the role of GluN2A in synapsis, we built two AAV-eGFP vectors: one codifying a specific shRNA anti GluN2A (AAV-sh2A), and the other carrying a shRNA scramble as control (AAV-shSc). In mature primary neuronal cultures transduced with AAV-sh2A or AAV-shSc We analyzed dendritic spines and also the expression of two synaptic proteins: Syn-1 and PSD95. As was expected, we observed by qPCR a decrease in GluN2A mRNA only in primary cultures transduced with AAVsh2A, without modifications in the other NMDAR subunits expression. Interestingly in those cultures where GluN2A was knockdown, we show a significant decrease in GluN1 protein. Although, we did not observe any change in GluN2B protein level. Furthermore, in those cultures we found an increase in dendritic spines number, at expenses ofimmature spines. In addition, the expression of Syn-1 and PSD95 was raised up in GluN2A knockdown cultures. These results suggest that GluN2A decreased expression seems to induce a rise in the synaptic spines, that would provoke changes in neuronal architecture and the return of the system to an immature state.