A deficiency of the GluN2C subunit of the N-methyl-D-aspartate receptor is neuroprotective in a mouse model of ischemic stroke.

The N-methyl-D-aspartate receptor (NMDAR) ion channel plays a pivotal role in the pathology of ischemic stroke. The functional receptor consists of two GluN1 subunits (a-h) and two GluN2 subunits (A/B/C/D), the expression of which are spatially and temporally regulated in pathological and physiological conditions. While the roles of the GluN2A and GluN2B subunit in ischemic stroke have been well developed, the role of the GluN2C subunit in ischemia is not well understood. Following middle carotid artery occlusion (MCAO), GluN2C-/- male mice displayed similar volumes of infarct as wild-type (WT) mice. However, GluN2C-/- mice showed decreased cerebral edema and an enhanced rate of neurological recovery compared to WT mice. The ischemic penumbra of GluN2C-/- mice showed fewer cytoarchitectural deficits and decreased tauopathy relative to WT mice. These neuroprotective changes in GluN2C-/- mice also corresponded with decreased expression of Fyn kinase and decreased phosphorylation of GluN2B subunit at Tyr1336. Lastly, a GluN2C deficiency modified the NMDAR/pro-survival signaling axis, as shown by increased levels of nuclear CREB(P-Ser133). Thus, the GluN2C subunit enhances ischemic stroke pathology by promoting neuronal dysfunction in the penumbra region.