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 stabilization and secretion of MMPs. Macrophages upregulate MMP-9 expression and secretion upon immunological challenge, and require its activity for migration during 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 contain calreticulin and PDI, in activated macrophages. Vesicular organelles of MMP-9 aligned along stable subsets of microtubules and colocalized with the anterograde molecular motor protein, kinesin. We demonstrated a functional contribution of stable MTs in the enhanced trafficking of MMP-9 extracellularly, and showed that heterogeneity exists in macrophage cell populations with respect to MMP-9 production.
Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/33690 |
Date | 29 November 2012 |
Creators | Hanania, Raed |
Contributors | Harrison, Rene E. |
Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
Language | en_ca |
Detected Language | English |
Type | Thesis |
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