title: Classically activated macrophages use stable microtubules for matrix metalloproteinase-9 (MMP-9) secretion.
abstract: As major effector cells of the innate immune response, macrophages must adeptly migrate from blood to infected tissues. Endothelial transmigration is accomplished by matrix metalloproteinase (MMP)-induced degradation of basement membrane and extracellular matrix components. The classical activation of macrophages with LPS and IFN-γ causes enhanced microtubule (MT) stabilization and secretion of MMPs. Macrophages up-regulate MMP-9 expression and secretion upon immunological challenge and require its activity for migration during the inflammatory response. However, the dynamics of MMP-9 production and intracellular distribution as well as the mechanisms responsible for its trafficking are unknown. Using immunofluorescent imaging, we localized intracellular MMP-9 to small Golgi-derived cytoplasmic vesicles that contained calreticulin and protein-disulfide isomerase in activated RAW 264.7 macrophages. We demonstrated vesicular organelles of MMP-9 aligned along stable subsets of MTs and showed that selective modulation of MT dynamics contributes to the enhanced trafficking of MMP-9 extracellularly. We found a Rab3D-dependent association of MMP-9 vesicles with the molecular motor kinesin, whose association with the MT network was greatly enhanced after macrophage activation. Finally, we implicated kinesin 5B and 3B isoforms in the effective trafficking of MMP-9 extracellularly.
authors.affiliation: Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada.
authors.forename: Raed
authors.initials: R
authors.lastname: Hanania
authors.forename: He Song
authors.initials: HS
authors.lastname: Sun
authors.forename: Kewei
authors.initials: K
authors.lastname: Xu
authors.forename: Sofia
authors.initials: S
authors.lastname: Pustylnik
authors.forename: Sujeeve
authors.initials: S
authors.lastname: Jeganathan
authors.forename: Rene E
authors.initials: RE
authors.lastname: Harrison
mesh_terms: D000818:Animals; D037282:Calreticulin / Q000378:metabolism; D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D006056:Golgi Apparatus / Q000201:enzymology; D016547:Kinesins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology / Q000502:physiology; D008262:Macrophage Activation / Q000187:drug effects / Q000502:physiology*; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D022142:Secretory Vesicles / Q000201:enzymology*; D015854:Up-Regulation / Q000187:drug effects; D020692:rab3 GTP-Binding Proteins / Q000378:metabolism
chemical_list: D037282:Calreticulin; D008070:Lipopolysaccharides; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse; C116711:Rab3d protein, mouse; D016547:Kinesins; D020692:rab3 GTP-Binding Proteins; D019704:Protein Disulfide-Isomerases