title: Early postnatal expression and localization of matrix metalloproteinases-2 and -9 during establishment of rat hippocampal synaptic circuitry.
abstract: Matrix metalloproteinases (MMPs) are extracellular proteolytic enzymes that contribute to pericellular remodeling in a variety of tissues, including brain, where they function in adult hippocampal synaptic structural and functional plasticity. Synaptic plasticity and remodeling are also important for development of connectivity, but it is unclear whether MMPs--particularly MMP-2 and -9, the major MMPs operative in brain--contribute at these stages. Here, we use a combination of biochemical and anatomical methods to characterize expression and localization of MMP-2 and MMP-9 in early postnatal and adult rat hippocampus. Gene and protein expression of these MMPs were evident throughout hippocampus at all ages examined, but expression levels were highest during the first postnatal week. MMP-2 and MMP-9 immunolocalized to punctate structures within the neuropil that codistributed with foci of proteolytic activity, as well as with markers of growing axons and synapses. Taken together, discrete foci of MMP proteolysis are likely important for actively shaping and remodeling cellular and connectional architecture as hippocampal circuitry is becoming established during early postnatal life.
authors.affiliation: Fishberg Department of Neuroscience, Friedman Brain Institute and The Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, 10029.
authors.forename: Paven K
authors.initials: PK
authors.lastname: Aujla
authors.forename: George W
authors.initials: GW
authors.lastname: Huntley
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D019062:Cell Adhesion Molecules, Neuron-Glia / Q000235:genetics / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006624:Hippocampus / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009415:Nerve Net / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000378:metabolism*; D016708:Synaptophysin / Q000235:genetics / Q000378:metabolism
chemical_list: D019062:Cell Adhesion Molecules, Neuron-Glia; D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D016708:Synaptophysin; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9
keywords: development; extracellular proteolysis; hippocampus; in situ zymography; synaptic plasticity