MMP2 and amyotrophic lateral sclerosis: It has been reported that MMP-2 and -9 increased expression along ALS progression31–33 and MMP-9 has been proposed as a determinant of selective motor neuron vulnerability33. In addition, there is strong evidence about  the involvement of both MMPs in ALS pathology either through direct neurotoxic effects or indirectly by eliciting cell death upon exacerbated degradation of extracellular matrix proteins32 or by triggering glial cell activation and disturbing their homeostatic signaling31–33.