Neuroserpin regulates the density of dendritic protrusions and dendritic spine shape in cultured hippocampal neurons.

Neuroserpin is a member of the serpin superfamily that is expressed principally in neurons of the central and peripheral nervous systems. Neuroserpin's spatial-temporal expression during development and in the adult brain suggests possible roles in synaptogenesis and synaptic plasticity. This is supported by behavioral changes in transgenic mice overexpressing neuroserpin. We have used an embryonic rat primary hippocampal neuron culture model to investigate whether neuroserpin can regulate elements of synaptic morphology that may be involved in these changes in cognitive function. Neuroserpin localized to axonal and dendritic compartments in cultured neurons and accumulated in synapsin-positive presynaptic terminals. Increased expression of neuroserpin resulted in an increase in the density of dendritic protrusions and alterations in dendritic spine shape. Our results identify neuroserpin as a new regulator of structural plasticity and suggest a cellular mechanism that may contribute to neuroserpin's effects on cognition.