Synaptic remodeling induced by axotomy of superior cervical ganglion neurons: Involvement of metalloproteinase-2

We previously demonstrated the involvement of the dystrophin–dystroglycan (Dys–DG) complex in the stabilization of intraganglionic synapses in rodent superior cervical ganglion (SCG) by investigating changes in the organization of their post-synaptic apparatus induced either by ganglionic neuron axotomy or by the lack of Dys in genetically dystrophic mdx mice, or by the combination of the two. A role of the matrix metalloproteinases (MMPs) MMP-2 and MMP-9 in the degradation of DG and, hence, in disrupting the connection between the extracellular matrix (ECM) and the cortical cytoskeleton, has recently been proposed. We hypothesized that the degradation by MMPs of ECM proteins and DG in ganglionic neurons may be involved in injury-induced synaptic detachment observed in rodent SCG. In this review, we report changes in MMP-2 and in the proteins involved in one of the enzymatic cascades of activation induced by axotomy of rat SCG neurons. This will be preceded by a description of our previous observations that led to investigate the role of MMP-2 in this experimental model.