Macrophages, phagocytosis and hijacking by pathogens
Mardi 21 mars 2017 11:00
- Duree : 1 heure
Lieu : Salle de Conférence de l’IAB - Rond Point de La Chantourne, 38700 La Tronche (arrêt de tram Grand Sablon, ligne B)
Orateur : Florence NIEDERGANG (Institute Cochin, Paris)
Phagosome formation depends on coordinated reorganization of cortical actin and membrane remodeling. We set up an original experimental approach to monitor the spatio-temporal reorganization of membrane and actin in nascent phagosomes in three dimensions and to visualize the phagosome closure step in living macrophages. We observed that vesicular delivery occurs at the base of the phagocytic cup where actin is depolymerized. We have highlighted new links between the actin and microtubules cytoskeleton, intracellular trafficking and signaling to the NFkB inflammatory pathway. We revealed a crosstalk between actin and dynamin-2 during phagosome formation, and demonstrated that
dynamin-2 plays a critical role in the closure of phagosomes.
Viral infections or chronic inflammatory conditions are reported to impair the phagocytic functions of macrophages, allowing the development of opportunistic pathogens. Macrophages are a target for the human immunodeficiency virus type 1 (HIV-1) and are considered as a productive viral reservoir. We have shown that HIV-1 impairs the uptake efficiency of human macrophages, as well as their degradative and activation capacities, leading to increased intracellular bacterial survival. Two different viral factors perturb the phagosome formation and the
microtubule-based phagosome maturation. We dissected the HIV-1 co-infections of human macrophages with the invasive non-typhoidal Salmonella Typhimurium bacteria that have emerged in Africa in HIV-infected patients and showed exquisite adaptation of these bacteria to the HIV-infected host. Together, our data aim to understand how opportunistic pathogens develop in virus- infected macrophages.
Contact : karin.sadoul@univ-grenoble-alpes.fr
Discipline évènement : (Biologie / Chimie)
Entité organisatrice : (IAB)
Nature évènement : (Séminaire)
Evènement répétitif : (Mardis de l’IAB)
Site de l'évènement : Pôle Santé / La Tronche
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