title: Matrix metalloproteinase-9 undergoes expression and activation during dendritic remodeling in adult hippocampus.
abstract: Neurons of adult brain are able to remodel their synaptic connections in response to various stimuli. Modifications of the peridendritic environment, including the extracellular matrix, are likely to play a role during synapse remodeling. Proteolytic disassembly of ECM is a complex process using the regulated actions of specific extracellular proteinases. One of best-characterized families of matrix-modifying enzymes is the matrix metalloproteinase (MMP) family. Here, we describe changes in the expression and function of two well known MMPs, MMP-9 and MMP-2, in adult rat brain before and after systemic administration of the glutamate receptor agonist kainate. Kainate application results in enhanced synaptic transmission and seizures followed by selective tissue remodeling, primarily in hippocampal dentate gyrus. MMP-9 but not MMP-2 was highly expressed by neurons in normal adult rat brain. MMP-9 protein was localized in neuronal cell bodies and dendrites. Kainate upregulated the level of MMP-9 mRNA and protein within hours after drug administration. This was followed several hours later by MMP-9 enzymatic activation. Within hippocampus, MMP-9 mRNA and activity were increased selectively in dentate gyrus, including its dendritic layer. In addition, MMP-9 mRNA levels decreased in areas undergoing neuronal cell loss. This unique spatiotemporal pattern of MMP-9 expression suggests its involvement in activity-dependent remodeling of dendritic architecture with possible effects on synaptic physiology.
authors.affiliation: Laboratory of Molecular Neurobiology, Nencki Institute, PL-02-093 Warsaw, Poland. szklarca@ninds.nih.gov
authors.forename: Arek
authors.initials: A
authors.lastname: Szklarczyk
authors.forename: Joanna
authors.initials: J
authors.lastname: Lapinska
authors.forename: Marcin
authors.initials: M
authors.lastname: Rylski
authors.forename: Ronald D G
authors.initials: RD
authors.lastname: McKay
authors.forename: Leszek
authors.initials: L
authors.lastname: Kaczmarek
mesh_terms: D000818:Animals; D003712:Dendrites / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D018690:Excitatory Amino Acid Agonists; D005109:Extracellular Matrix / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007608:Kainic Acid; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D009928:Organ Specificity; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012640:Seizures / Q000139:chemically induced / Q000378:metabolism
chemical_list: D018690:Excitatory Amino Acid Agonists; D012333:RNA, Messenger; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D007608:Kainic Acid