To explore the functional relationship between Crem and neuroplasticity identified in our network analysis, Crem was over-expressed in primary striatal neurons and structural neuromorphology was assessed. Neurons over-expressing Crem showed a profound attenuation in the normal spine developmental observed between 7 and 14 days in vitro (DIV). Crem over-expressing medium spiny neurons (marked by DARPP-32 immunoreactivity) exhibited significantly less total dendritic spines at DIV14 when compared to controls (F1,16=14.07, p=0.002, Fig. 5d), yet there was no difference at DIV7 (F1,13=0.04, p=0.85, Fig. 5d). This effect was most pronounced for thin spines that, given their more plastic and dynamic nature, were more abundant in developing neurons (Fig. 5d). These data suggest that Crem is a key regulator of spine morphology and development in striatal medium spiny neurons.
