An increasing body of data has shown that matrix metalloproteinase-9 (MMP-9), an extracellularly acting, Zn2+-dependent endopeptidase, is important not only for pathologies of the central nervous system but also for neuronal plasticity. Here, we use three independent experimental models to show that enzymatic activity of MMP-9 causes elongation and thinning of dendritic spines in the hippocampal neurons. These models are: a recently developed transgenic rat overexpressing autoactivating MMP-9, dissociated neuronal cultures, and organotypic neuronal cultures treated with recombinant autoactivating MMP-9. This dendritic effect is mediated by integrin β1 signalling. MMP-9 treatment also produces a change in the decay time of miniature synaptic currents; however, it does not change the abundance and localization of synaptic markers in dendritic protrusions. Our results, considered together with several recent studies, strongly imply that MMP-9 is functionally involved in synaptic remodelling.
This work was supported by The Polish Ministry of Science and Higher Education research grant P-N/030/2006 (J.W.M. and L.K.), the 7th FP EU grant Memstick (M.G.S. and L.K.), the Polish–Norwegian Research Fund grant (PNRF-96, G.M.W. and L.K.) and fellowships from the Foundation for Polish Science (P.M.) and the European Molecular Biology Organization (J.W.). M.S. and J.W.M. were partially supported by the Polish Ministry for Science grant no. N401 541540.
- Accepted May 28, 2011.
- © 2011.