SorCS2 modulates neurovascular coupling via glutamatergic and calcium signaling in astrocytes

Abstract

SorCS2 is involved in trafficking of membrane receptors and transporters. SorCS2 is implicated in brain disorders, but the mechanism remains uncertain. We hypothesized that SorCS2 expression is important for neurovascular coupling. Brains from P8 and 2-month-old wild type mice were stained for SorCS2 and compared to SorCS2 knockouts (Sorcs2-/-). Changes in cerebral perfusion in response to sensory stimulation, i.e., neurovascular coupling, were comparedin vivo. Neurovascular coupling was also assessed ex vivo in brain slices loaded with calcium-sensitive dye. Proteomics of astrocytes was analyzed for ingenuity pathways. SorCS2 was strongly expressed in astrocytic endfeet of P8 mice but only in few astrocytes from 2-month-old brains.Sorcs2-/-mice demonstrated reduced neurovascular coupling. This was associated with reduced astrocytic calcium response to neuronal excitation inSorcs2-/-mice. No difference in cerebral artery caliber nor in endothelial function was seen between wild type andSorcs2-/-mice. Proteomics indicated reduced glutamatergic signaling and suppressed calcium signaling inSorcs2-/-astrocytes. We suggest that SorCS2 expression is important for neurovascular coupling due to modulation of glutamatergic and calcium signaling in astrocytes.