Coxiella burnetii induces reorganization of the actin cytoskeleton in human monocytes
| Autor: | Véronique Jacomo, Jean-Louis Mege, Christian Capo, Patrice Boquet, Didier Raoult, Sonia Meconi |
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| Rok vydání: | 1998 |
| Předmět: |
Amanitins
Immunology Arp2/3 complex macromolecular substances Microbiology Filamentous actin Bacterial Adhesion Monocytes GTP-Binding Proteins RhoB GTP-Binding Protein Humans Cytoskeleton rhoB GTP-Binding Protein Actin Fluorescent Dyes biology Actin remodeling Membrane Proteins Actin cytoskeleton Coxiella burnetii biology.organism_classification bacterial infections and mycoses Actins Cell biology Infectious Diseases biology.protein Microscopy Electron Scanning Molecular and Cellular Pathogenesis bacteria Parasitology Q Fever |
| Zdroj: | Infection and immunity. 66(11) |
| ISSN: | 0019-9567 |
| Popis: | Coxiella burnetii , an obligate intracellular bacterium which survives in myeloid cells, causes Q fever in humans. We previously demonstrated that virulent C. burnetii organisms are poorly internalized by monocytes compared to avirulent variants. We hypothesized that a differential mobilization of the actin cytoskeleton may account for this distinct phagocytic behavior. Scanning electron microscopy demonstrated that virulent C. burnetii stimulated profound and polymorphic changes in the morphology of THP-1 monocytes, consisting of membrane protrusions and polarized projections. These changes were transient, requiring 5 min to reach their maximum extent and vanishing after 60 min of incubation. In contrast, avirulent variants of C. burnetii did not induce any significant changes in cell morphology. The distribution of filamentous actin (F-actin) was then studied with a specific probe, bodipy phallacidin. Virulent C. burnetii induced a profound and transient reorganization of F-actin, accompanied by an increase in the F-actin content of THP-1 cells. F-actin was colocalized with myosin in cell protrusions, suggesting that actin polymerization and the tension of actin-myosin filaments play a role in C. burnetii -induced morphological changes. In addition, contact between the cell and the bacterium seems to be necessary to induce cytoskeleton reorganization. Bacterial supernatants did not stimulate actin remodeling, and virulent C. burnetii organisms were found in close apposition with F-actin protrusions. The manipulation of the actin cytoskeleton by C. burnetii may therefore play a critical role in the internalization strategy of this bacterium. |
| Databáze: | OpenAIRE |
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