Biomedical research institute
     

    Research program

    • Cross talk between signaling, intracellular trafficking and cytoskeleton for efficient phagocytosis in macrophages  (F. Niedergang)                                               

    Phagocytosis depends on reorganization of cortical actin coordinated with the recruitment of intracellular compartments, which fuse with the plasma membrane, a process necessary to for actin dynamics and efficient particle internalization [1]. We showed that mDia1, an actin nucleator of the formin family, is required downstream of the CR3 integrin receptors and highlighted an original dialogue between the microtubules and actin [2, 3]. We revealed that the B cell lymphoma/leukemia-10 (Bcl10) protein, well known for its role in stimulating immune responses via NF-kB, is unexpectedly involved in actin dynamics during phagocytosis by controlling the trafficking and signaling [4].  We developed an original method based on evanescent wave microscopy to monitor the spatiotemporal reorganization of membrane and actin in nascent phagosomes in three dimensions [5], which allowed us to identify that dynamin2 as crucial to control phagosome formation and closure [6]. We also revealed recently that the negative Arp2/3 regulator Arpin is required for efficient phagosome formation [7]. We now study in details early steps of phagocytic receptors clustering and force generation, taking advantage of unique deformable lipid droplets, in collaboration with Jacques Fattaccioli (Laboratoire microfluidique Institut Pierre Gilles de Gennes – CNRS, ENS, Sorbonne Université) and Jean-Maurice MALLET (Laboratoire des Biomolécules, CNRS, ENS, Sorbonne Université) in the context of a CNRS 80 PRIME programme.

    •  Perturbations of the phagocytic and activation functions of macrophages by viral infections (HIV, respiratory virus) and bacterial co-infections. (E. Bonnefoy, F. Niedergang, F. Ouaaz)

                                                                                                                                                                                                                                                                                                                                                                                                                             

    Macrophages are a major initial target of the human immunodeficiency virus (HIV) and represent a productive reservoir for the virus because of their resistance to cytopathic effects. Infection of macrophages by HIV-1 causes a severe impairment of the functions of these cells, which allows the development of opportunistic pathogens. We demonstrated that macrophages infected with HIV-1 exhibit defects in phagocytosis, due to the virulence factor Nef [8]. We also showed that the Vpr viral protein interacts with microtubule associated motors, which impairs phagosome maturation and bacterial clearance [9]. We continue to characterize the development of opportunistic bacteria, especially invasive Salmonella Typhimurium (iNTS) strains emerged in African HIV-1-infected patients (coll Dr Melita Gordon, Liverpool and Malawi) [10].

    Alveolar macrophages are the most abundant innate immune cells present in the airways and are thought to play a crucial role in airway homeostasis. In chronic obstructive pulmonary disease (COPD), their numbers are increased but they exhibit defective clearance capacities and exaggerated inflammatory responses, which is often exacerbated by infection with human rhinoviruses [11]. We are dissecting the mechanisms leading to this defective phagocytosis, in collaboration with Astra Zeneca and Prof. Pierre-Regis Burgel (Hôpital Cochin). We revealed that Arpin is targeted by human rhinoviruses, explaining the defective bacterial uptake in macrophages [7]. A transcriptomic analysis of rhinovirus-treated macrophages allows further identification of new host targets.

    •  Capture by dendritic cells and antigen recycling (F. Ouaaz).

     

    We described in dendritic cells (DCs) a mechanism of recycling to the extracellular milieu of non-degraded material from late endocytic compartments that we called “regurgitation” [17]. This is regulated by the small G protein Rab27 and the chemokine CXCL13, which is essential to attract B lymphocytes in the lymph nodes. B cells require recognition of native antigen to be activated, but how this encounter occurs is still unclear. Our results reveal a unique property of dendritic cells that might play an important role in the activation of B lymphocytes [17,18].

    We now analyze the molecular machineries regulating this type of recycling in DCs. We also analyze the antigen transfer between DCs and B cells in lymph nodes using intravital microscopy and will determine the development of humoral immune responses in vivo.

     

     

    REFERENCES

    1.         Niedergang, F., and Grinstein, S. (2018). How to build a phagosome: new concepts for an old process. Curr Opin Cell Biol 50, 57-63.

    2.         Colucci-Guyon, E., Niedergang, F., Wallar, B.J., Peng, J., Alberts, A.S., and Chavrier, P. (2005). A role for mammalian diaphanous-related formins in complement receptor (CR3)-mediated phagocytosis in macrophages. Curr Biol 15, 2007-2012.

    3.         Lewkowicz, E., Herit, F., Le Clainche, C., Bourdoncle, P., Perez, F., and Niedergang, F. (2008). The microtubule-binding protein CLIP-170 coordinates mDia1 and actin reorganization during CR3-mediated phagocytosis. J Cell Biol 183, 1287-1298.

    4.         Marion, S., Mazzolini, J., Herit, F., Bourdoncle, P., Kambou-Pene, N., Hailfinger, S., Sachse, M., Ruland, J., Benmerah, A., Echard, A., et al. (2012). The NF-kappaB Signaling Protein Bcl10 Regulates Actin Dynamics by Controlling AP1 and OCRL-Bearing Vesicles. Dev Cell 23, 954-967.

    5.         Marie-Anais, F., Mazzolini, J., Bourdoncle, P., and Niedergang, F. (2016). "Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy (TIRFM). J Vis Exp.

    6.         Marie-Anais, F., Mazzolini, J., Herit, F., and Niedergang, F. (2016). Dynamin-Actin Cross Talk Contributes to Phagosome Formation and Closure. Traffic 17, 487-499.

    7.         Jubrail, J., Africano-Gomez, K., Herit, F., Mularski, A., Bourdoncle, P., Oberg, L., Israelsson, E., Burgel, P.R., Mayer, G., Cunoosamy, D.M., et al. (2020). Arpin is critical for phagocytosis in macrophages and is targeted by human rhinovirus. EMBO Rep 21, e47963.

    8.         Mazzolini, J., Herit, F., Bouchet, J., Benmerah, A., Benichou, S., and Niedergang, F. (2010). Inhibition of phagocytosis in HIV-1-infected macrophages relies on Nef-dependent alteration of focal delivery of recycling compartments. Blood 115, 4226-4236.

    9.         Dumas, A., Le-Bury, G., Marie-Anais, F., Herit, F., Mazzolini, J., Guilbert, T., Bourdoncle, P., Russell, D.G., Benichou, S., Zahraoui, A., et al. (2015). The HIV-1 protein Vpr impairs phagosome maturation by controlling microtubule-dependent trafficking. J Cell Biol 211, 359-372.

    10.       Le-Bury, G., Deschamps, C., Kizilyaprak, C., Blanchard, W., Daraspe, J., Dumas, A., Gordon, M.A., Hinton, J.C.D., Humbel, B.M., and Niedergang, F. (2020). Increased intracellular survival of Salmonella Typhimurium ST313 in HIV-1-infected primary human macrophages is not associated with Salmonella hijacking the HIV compartment. Biol Cell 112, 92-101.

    11.       Jubrail, J., Kurian, N., and Niedergang, F. (2017). Macrophage phagocytosis cracking the defect code in COPD. Biomed J 40, 305-312.