GluN2A KD alters neuronal synaptic plasticity in neuronal mature cultures

JERUSALINSKY, DIANA A.; ACUTAIN, M. FLORENCIA; SALVETTI, ANNA; VAZQUEZ, CECILIA ALEJANDRA; BAEZ M. VERÓNICA

Montreal

Congreso; ISN-ASN Meeting 2019; 2019

International Society for Neurochemistry-American Society for Neurochemistry

Synaptic plasticity refers to long lasting changes in synapses that have been related to the structural bases of memory and learning processes. For several years, NMDA receptors (NMDAR) have been involved in those pro­cesses as well as in several neuropathologies. NMDAR are composed by two GluN1 obligatory subunits and two regulatory subunits: GluN2 (A-D) or GluN3 (A-B). In cognitive related brain structures GluN2A and GluN2B are the most expressed regulatory subunits, that undergo a tightly regulation. Whereas GluN2B expression is characteristic of immature synapses, GluN2A is present in mature synapses. In order to better understand the role of GluN2A in synapsis, we transduced mature neuronal cultures with AAV-eGFP vectors: one codifying a specific shRNA anti GluN2A, AAV-sh2A, and the other carrying a shRNA scramble as control, AAV-shSc. We verified that AAV-sh2A knocks down GluN2A mRNA and pro­tein levels (GluN2A KD). Moreover we evaluated neuronal morphology and two synaptic proteins: Syn-1 and PSD95. In GluN2A KD cultures we confirmed the in­crease in dendritic arbor complexity ob­served previously. Interestingly, in those cultures we found a significant decrease in GluN1 protein, while GluN2B protein levels did not change. Furthermore, in those cultures the ex­pression of Syn-1 and PSD95 was in­creased, which suggest that synaptic function was altered. For these reason we analyzed GluN2A KD cultures by Ca+2 imaging and ob­served changes in the excitability of neurons after chemical LTP. These results suggest that GluN2A KD induce a rearrangement of NMDAR ex­pression that modifies synaptic physiology