Publications

@article{pmid29874861b,

title = {Rv0613c/MSMEG_1285 Interacts with HBHA and Mediates Its Proper Cell-Surface Exposure in Mycobacteria},

author = {Romain Veyron-Churlet and Vincent Dupres and Jean-Michel Saliou and Frank Lafont and Dominique Raze and Camille Locht},

doi = {10.3390/ijms19061673},

issn = {1422-0067},

year  = {2018},

date = {2018-06-01},

journal = {Int J Mol Sci},

volume = {19},

number = {6},

abstract = {Heparin-binding haemagglutinin (HBHA) is a surface-exposed virulence factor of  and is involved in the binding of mycobacteria to non-phagocytic cells, allowing for extra-pulmonary dissemination of the bacilli. Despite its surface exposure, HBHA is not produced as a pre-protein containing a typical cleavable N-terminal signal peptide and is thus likely secreted by a Sec-independent, as of yet unknown mechanism. Here, we used the bacterial adenylate cyclase two-hybrid system to identify the proteins encoded by  and  as being able to interact with HBHA. Our study was focused on Rv0613c, as it showed more consistent interactions with HBHA than MmpL14. Deletion of its orthologous gene  in recombinant  producing HBHA from  resulted in the loss of proper surface exposure of HBHA, as evidenced by atomic force microscopy. Furthermore, the lack of  also abolished the clumping phenotype and rough colony morphology of the recombinant  and reduced its adherence to A549 epithelial cells. These phenotypes have previously been associated with surface-exposed HBHA. Thus, MSMEG_1285 is directly involved in the proper cell-surface exposure of HBHA. These observations identify MSMEG_1285/Rv0613c as the first accessory protein involved in the cell surface exposure of HBHA.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid30314966,

title = {ESCRT-mediated lysosome repair precedes lysophagy and promotes cell survival},

author = {Maja Radulovic and Kay O Schink and Eva M Wenzel and Viola Nähse and Antonino Bongiovanni and Frank Lafont and Harald Stenmark},

doi = {10.15252/embj.201899753},

issn = {1460-2075},

year  = {2018},

date = {2018-01-01},

journal = {EMBO J},

volume = {37},

number = {21},

abstract = {Although lysosomes perform a number of essential cellular functions, damaged lysosomes represent a potential hazard to the cell. Such lysosomes are therefore engulfed by autophagic membranes in the process known as lysophagy, which is initiated by recognition of luminal glycoprotein domains by cytosolic lectins such as Galectin-3. Here, we show that, under various conditions that cause injury to the lysosome membrane, components of the endosomal sorting complex required for transport (ESCRT)-I, ESCRT-II, and ESCRT-III are recruited. This recruitment occurs before that of Galectin-3 and the lysophagy machinery. Subunits of the ESCRT-III complex show a particularly prominent recruitment, which depends on the ESCRT-I component TSG101 and the TSG101- and ESCRT-III-binding protein ALIX Interference with ESCRT recruitment abolishes lysosome repair and causes otherwise reversible lysosome damage to become cell lethal. Vacuoles containing the intracellular pathogen  show reversible ESCRT recruitment, and interference with this recruitment reduces intravacuolar bacterial replication. We conclude that the cell is equipped with an endogenous mechanism for lysosome repair which protects against lysosomal damage-induced cell death but which also provides a potential advantage for intracellular pathogens.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29720971,

title = {Oligomannose-Rich Membranes of Dying Intestinal Epithelial Cells Promote Host Colonization by Adherent-Invasive },

author = {Tetiana Dumych and Nao Yamakawa and Adeline Sivignon and Estelle Garenaux and Stefania Robakiewicz and Bernadette Coddeville and Antonino Bongiovanni and Fabrice Bray and Nicolas Barnich and Sabine Szunerits and Christian Slomianny and Martin Herrmann and Sébastien G Gouin and Alexander D Lutsyk and Luis E Munoz and Frank Lafont and Christian Rolando and Rostyslav Bilyy and Julie M J Bouckaert},

doi = {10.3389/fmicb.2018.00742},

issn = {1664-302X},

year  = {2018},

date = {2018-01-01},

journal = {Front Microbiol},

volume = {9},

pages = {742},

abstract = {A novel mechanism is revealed by which clinical isolates of adherent-invasive  (AIEC) penetrate into the epithelial cell layer, replicate, and establish biofilms in Crohn's disease. AIEC uses the FimH fimbrial adhesin to bind to oligomannose glycans on the surface of host cells. Oligomannose glycans exposed on early apoptotic cells are the preferred binding targets of AIEC, so apoptotic cells serve as potential entry points for bacteria into the epithelial cell layer. Thereafter, the bacteria propagate laterally in the epithelial intercellular spaces. We demonstrate oligomannosylation at two distinct sites of a glycoprotein receptor for AIEC, carcinoembryonic antigen related cell adhesion molecule 6 (CEACAM6 or CD66c), on human intestinal epithelia. After bacterial binding, FimH interacts with CEACAM6, which then clusters. The presence of the highest-affinity epitope for FimH, oligomannose-5, on CEACAM6 is demonstrated using LC-MS/MS. As mannose-dependent infections are abundant, this mechanism might also be used by other adherent-invasive pathogens.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29141986,

title = {ArfGAP1 restricts  entry by controlling the actin cytoskeleton},

author = {Ok-Ryul Song and Christophe J Queval and Raffaella Iantomasi and Vincent Delorme and Sabrina Marion and Romain Veyron-Churlet and Elisabeth Werkmeister and Michka Popoff and Isabelle Ricard and Samuel Jouny and Nathalie Deboosere and Frank Lafont and Alain Baulard and Edouard Yeramian and Laurent Marsollier and Eik Hoffmann and Priscille Brodin},

doi = {10.15252/embr.201744371},

issn = {1469-3178},

year  = {2018},

date = {2018-01-01},

journal = {EMBO Rep},

volume = {19},

number = {1},

pages = {29--42},

abstract = {The interaction of  (Mtb) with pulmonary epithelial cells is critical for early stages of bacillus colonization and during the progression of tuberculosis. Entry of Mtb into epithelial cells has been shown to depend on F-actin polymerization, though the molecular mechanisms are still unclear. Here, we demonstrate that mycobacterial uptake into epithelial cells requires rearrangements of the actin cytoskeleton, which are regulated by ADP-ribosylation factor 1 (Arf1) and phospholipase D1 (PLD1), and is dependent on the M3 muscarinic receptor (MR). We show that this pathway is controlled by Arf GTPase-activating protein 1 (ArfGAP1), as its silencing has an impact on actin cytoskeleton reorganization leading to uncontrolled uptake and replication of Mtb. Furthermore, we provide evidence that this pathway is critical for mycobacterial entry, while the cellular infection with other pathogens, such as  and , is not affected. Altogether, these results reveal how cortical actin plays the role of a barrier to prevent mycobacterial entry into epithelial cells and indicate a novel role for ArfGAP1 as a restriction factor of host-pathogen interactions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29956233,

title = {High-Resolution and High-Speed Atomic Force Microscope Imaging},

author = {Francesca Zuttion and Lorena Redondo-Morata and Arin Marchesi and Ignacio Casuso},

doi = {10.1007/978-1-4939-8591-3_11},

issn = {1940-6029},

year  = {2018},

date = {2018-01-01},

journal = {Methods Mol Biol},

volume = {1814},

pages = {181--200},

abstract = {The advent of high-speed atomic force microscopy (HS-AFM) over the recent years has opened up new horizons for the study of structure, function and dynamics of biological molecules. HS-AFM is capable of 1000 times faster imaging than conventional AFM. This circumstance uniquely enables the observation of the dynamics of all the molecules present in the imaging area. Over the last 10 years, the HS-AFM has gone from a prototype-state technology that only a few labs in the world had access to (including ours) to an established commercialized technology that is present in tens of labs around the world. In this protocol chapter we share with the readers our practical know-how on high resolution HS-AFM imaging.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29371496b,

title = {Role of Hydrophobins in Aspergillus fumigatus},

author = {Isabel Valsecchi and Vincent Dupres and Emmanuel Stephen-Victor and J Iñaki Guijarro and John Gibbons and Rémi Beau and Jagadeesh Bayry and Jean-Yves Coppee and Frank Lafont and Jean-Paul Latgé and Anne Beauvais},

doi = {10.3390/jof4010002},

issn = {2309-608X},

year  = {2017},

date = {2017-12-01},

journal = {J Fungi (Basel)},

volume = {4},

number = {1},

abstract = {Resistance of  conidia to desiccation and their capacity to reach the alveoli are partly due to the presence of a hydrophobic layer composed of a protein from the hydrophobin family, called RodA, which covers the conidial surface. In  there are seven hydrophobins (RodA-RodG) belonging to class I and III. Most of them have never been studied. We constructed single and multiple hydrophobin-deletion mutants until the generation of a hydrophobin-free mutant. The phenotype, immunogenicity, and virulence of the mutants were studied.  is the most expressed hydrophobin in sporulating cultures, whereas  is upregulated in biofilm conditions and in vivo Only RodA, however, is responsible for rodlet formation, sporulation, conidial hydrophobicity, resistance to physical insult or anionic dyes, and immunological inertia of the conidia. None of the hydrophobin plays a role in biofilm formation or its hydrophobicity. RodA is the only needed hydrophobin in , conditioning the structure, permeability, hydrophobicity, and immune-inertia of the cell wall surface in conidia. Moreover, the defect of rodlets on the conidial cell wall surface impacts on the drug sensitivity of the fungus.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28743738,

title = {Premature termination codon readthrough in human cells occurs in novel cytoplasmic foci and requires UPF proteins},

author = {Jieshuang Jia and Elisabeth Werkmeister and Sara Gonzalez-Hilarion and Catherine Leroy and Dieter C Gruenert and Frank Lafont and David Tulasne and Fabrice Lejeune},

doi = {10.1242/jcs.198176},

issn = {1477-9137},

year  = {2017},

date = {2017-09-01},

journal = {J Cell Sci},

volume = {130},

number = {18},

pages = {3009--3022},

abstract = {Nonsense-mutation-containing messenger ribonucleoprotein particles (mRNPs) transit through cytoplasmic foci called P-bodies before undergoing nonsense-mediated mRNA decay (NMD), a cytoplasmic mRNA surveillance mechanism. This study shows that the cytoskeleton modulates transport of nonsense-mutation-containing mRNPs to and from P-bodies. Impairing the integrity of cytoskeleton causes inhibition of NMD. The cytoskeleton thus plays a crucial role in NMD. Interestingly, disruption of actin filaments results in both inhibition of NMD and activation of premature termination codon (PTC) readthrough, while disruption of microtubules causes only NMD inhibition. Activation of PTC readthrough occurs concomitantly with the appearance of cytoplasmic foci containing UPF proteins and mRNAs with nonsense mutations but lacking the P-body marker DCP1a. These findings demonstrate that in human cells, PTC readthrough occurs in novel 'readthrough bodies' and requires the presence of UPF proteins.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28430827,

title = {Dual role of the Toxoplasma gondii clathrin adaptor AP1 in the sorting of rhoptry and microneme proteins and in parasite division},

author = {Kannan Venugopal and Elisabeth Werkmeister and Nicolas Barois and Jean-Michel Saliou and Anais Poncet and Ludovic Huot and Fabien Sindikubwabo and Mohamed Ali Hakimi and Gordon Langsley and Frank Lafont and Sabrina Marion},

doi = {10.1371/journal.ppat.1006331},

issn = {1553-7374},

year  = {2017},

date = {2017-04-01},

journal = {PLoS Pathog},

volume = {13},

number = {4},

pages = {e1006331},

abstract = {Toxoplasma gondii possesses a highly polarized secretory system, which efficiently assembles de novo micronemes and rhoptries during parasite replication. These apical secretory organelles release their contents into host cells promoting parasite invasion and survival. Using a CreLox-based inducible knock-out strategy and the ddFKBP over-expression system, we unraveled novel functions of the clathrin adaptor complex TgAP1. First, our data indicate that AP1 in T. gondii likely functions as a conserved heterotetrameric complex composed of the four subunits γ, β, μ1, σ1 and interacts with known regulators of clathrin-mediated vesicular budding such as the unique ENTH-domain containing protein, which we named Epsin-like protein (TgEpsL). Disruption of the μ1 subunit resulted in the mis-sorting of microneme proteins at the level of the Trans-Golgi-Network (TGN). Furthermore, we demonstrated that TgAP1 regulates rhoptry biogenesis by activating rhoptry protein exit from the TGN, but also participates in the post-Golgi maturation process of preROP compartments into apically anchored club-shaped mature organelles. For this latter activity, our data indicate a specific functional relationship between TgAP1 and the Rab5A-positive endosome-like compartment. In addition, we unraveled an original role for TgAP1 in the regulation of parasite division. APμ1-depleted parasites undergo normal daughter cell budding and basal complex assembly but fail to segregate at the end of cytokinesis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28367819,

title = {Autophagy, ATG proteins and infectious diseases},

author = {Isabelle Vergne and Frank Lafont and Lucile Espert and Audrey Esclatine and Martine Biard-Piechaczyk},

doi = {10.1051/medsci/20173303019},

issn = {1958-5381},

year  = {2017},

date = {2017-03-01},

urldate = {2017-03-01},

journal = {Med Sci (Paris)},

volume = {33},

number = {3},

pages = {312--318},

abstract = {One of the main functions of the autophagy pathway is to control infections. Intracellular micro-organisms or their products once internalized in the host cell can be directly degraded by autophagy, a process called xenophagy. Autophagy is also involved in other innate immune responses and participates to the adaptive immune system. In addition, several autophagy proteins play a role in the development of infectious diseases independently of their role in the autophagy pathway. To replicate efficiently, pathogens have therefore evolved to counteract this process or to exploit it to their own profit. The review focuses on the relationship between autophagy and micro-organisms, which is highly diverse and complex. Many research groups are now working on this topic to find new therapeutics and/or vaccines. Given the large number of data, we have addressed this subject through some representative examples.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27993700,

title = {Adhesiveness of opportunistic Staphylococcus aureus to materials used in dental office: In vitro study},

author = {Abderrahmen Merghni and Karima Bekir and Yassine Kadmi and Ines Dallel and Sébastien Janel and Simone Bovio and Nicolas Barois and Frank Lafont and Maha Mastouri},

doi = {10.1016/j.micpath.2016.12.014},

issn = {1096-1208},

year  = {2017},

date = {2017-02-01},

journal = {Microb Pathog},

volume = {103},

pages = {129--134},

abstract = {Staphylococcus aureus (S. aureus) is one of several opportunistic microbial pathogens associated with many healthcare problems. In the present study, S. aureus was assessed for its biofilm-forming ability on materials routinely used in dental offices, including stainless steel (SS), polyethylene (PE), and polyvinyl chloride (PVC). Materials that were tested were characterized for roughness (Ra) and surface free energy (SFE). The adhesion forces exerted by S. aureus to each substratum were investigated using atomic force microscopy (AFM), and biofilm formation was quantitatively assessed by crystal violet staining assay. AFM measurements demonstrated that the strongest adhesion forces (20 nN) were exerted on the PE surfaces (P < 0.05) and depended more on Ra. In addition, the results of biofilm formation capability indicated that S. aureus exhibited more affinity to SS materials when compared to the other materials (P < 0.05). This ability of biofilm formation seems to be more correlated to SFE (R = 0.65). Hence, control of the surface properties of materials used in dental practices is of crucial importance for preventing biofilm formation on dental materials to be used for patients' dental care.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28643776,

title = {Ezrin enhances line tension along transcellular tunnel edges via NMIIa driven actomyosin cable formation},

author = {Caroline Stefani and David Gonzalez-Rodriguez and Yosuke Senju and Anne Doye and Nadia Efimova and Sébastien Janel and Justine Lipuma and Meng Chen Tsai and Daniel Hamaoui and Madhavi P Maddugoda and Olivier Cochet-Escartin and Coline Prévost and Frank Lafont and Tatyana Svitkina and Pekka Lappalainen and Patricia Bassereau and Emmanuel Lemichez},

doi = {10.1038/ncomms15839},

issn = {2041-1723},

year  = {2017},

date = {2017-01-01},

journal = {Nat Commun},

volume = {8},

pages = {15839},

abstract = {Transendothelial cell macroaperture (TEM) tunnels control endothelium barrier function and are triggered by several toxins from pathogenic bacteria that provoke vascular leakage. Cellular dewetting theory predicted that a line tension of uncharacterized origin works at TEM boundaries to limit their widening. Here, by conducting high-resolution microscopy approaches we unveil the presence of an actomyosin cable encircling TEMs. We develop a theoretical cellular dewetting framework to interpret TEM physical parameters that are quantitatively determined by laser ablation experiments. This establishes the critical role of ezrin and non-muscle myosin II (NMII) in the progressive implementation of line tension. Mechanistically, fluorescence-recovery-after-photobleaching experiments point for the upstream role of ezrin in stabilizing actin filaments at the edges of TEMs, thereby favouring their crosslinking by NMIIa. Collectively, our findings ascribe to ezrin and NMIIa a critical function of enhancing line tension at the cell boundary surrounding the TEMs by promoting the formation of an actomyosin ring.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28569760,

title = {Strength of Neisseria meningitidis binding to endothelial cells requires highly-ordered CD147/β-adrenoceptor clusters assembled by alpha-actinin-4},

author = {Nawal Maïssa and Valentina Covarelli and Sébastien Janel and Beatrice Durel and Nandi Simpson and Sandra C Bernard and Liliana Pardo-Lopez and Haniaa Bouzinba-Ségard and Camille Faure and Mark G H Scott and Mathieu Coureuil and Philippe C Morand and Frank Lafont and Xavier Nassif and Stefano Marullo and Sandrine Bourdoulous},

doi = {10.1038/ncomms15764},

issn = {2041-1723},

year  = {2017},

date = {2017-01-01},

journal = {Nat Commun},

volume = {8},

pages = {15764},

abstract = {Neisseria meningitidis (meningococcus) is an invasive bacterial pathogen that colonizes human vessels, causing thrombotic lesions and meningitis. Establishment of tight interactions with endothelial cells is crucial for meningococci to resist haemodynamic forces. Two endothelial receptors, CD147 and the β2-adrenergic receptor (βAR), are sequentially engaged by meningococci to adhere and promote signalling events leading to vascular colonization, but their spatiotemporal coordination is unknown. Here we report that CD147 and βAR form constitutive hetero-oligomeric complexes. The scaffolding protein α-actinin-4 directly binds to the cytosolic tail of CD147 and governs the assembly of CD147-βAR complexes in highly ordered clusters at bacterial adhesion sites. This multimolecular assembly process increases the binding strength of meningococci to endothelial cells under shear stress, and creates molecular platforms for the elongation of membrane protrusions surrounding adherent bacteria. Thus, the specific organization of cellular receptors has major impacts on host-pathogen interaction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28528632,

title = {CLAFEM: Correlative light atomic force electron microscopy},

author = {Sébastien Janel and Elisabeth Werkmeister and Antonino Bongiovanni and Frank Lafont and Nicolas Barois},

doi = {10.1016/bs.mcb.2017.03.010},

issn = {0091-679X},

year  = {2017},

date = {2017-01-01},

journal = {Methods Cell Biol},

volume = {140},

pages = {165--185},

abstract = {Atomic force microscopy (AFM) is becoming increasingly used in the biology field. It can give highly accurate topography and biomechanical quantitative data, such as adhesion, elasticity, and viscosity, on living samples. Nowadays, correlative light electron microscopy is a must-have tool in the biology field that combines different microscopy techniques to spatially and temporally analyze the structure and function of a single sample. Here, we describe the combination of AFM with superresolution light microscopy and electron microscopy. We named this technique correlative light atomic force electron microscopy (CLAFEM) in which AFM can be used on fixed and living cells in association with superresolution light microscopy and further processed for transmission or scanning electron microscopy. We herein illustrate this approach to observe cellular bacterial infection and cytoskeleton. We show that CLAFEM brings complementary information at the cellular level, from on the one hand protein distribution and topography at the nanometer scale and on the other hand elasticity at the piconewton scales to fine ultrastructural details.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28544095,

title = {Phenotypic assays for Mycobacterium tuberculosis infection},

author = {Ok-Ryul Song and Nathalie Deboosere and Vincent Delorme and Christophe J Queval and Gaspard Deloison and Elisabeth Werkmeister and Frank Lafont and Alain Baulard and Raffaella Iantomasi and Priscille Brodin},

doi = {10.1002/cyto.a.23129},

issn = {1552-4930},

year  = {2017},

date = {2017-01-01},

journal = {Cytometry A},

volume = {91},

number = {10},

pages = {983--994},

abstract = {Tuberculosis (TB) is still a major global threat, killing more than one million persons each year. With the constant increase of Mycobacterium tuberculosis strains resistant to first- and second-line drugs, there is an urgent need for the development of new drugs to control the propagation of TB. Although screenings of small molecules on axenic M. tuberculosis cultures were successful for the identification of novel putative anti-TB drugs, new drugs in the development pipeline remains scarce. Host-directed therapy may represent an alternative for drug development against TB. Indeed, M. tuberculosis has multiple specific interactions within host phagocytes, which may be targeted by small molecules. In order to enable drug discovery strategies against microbes residing within host macrophages, we developed multiple fluorescence-based HT/CS phenotypic assays monitoring the intracellular replication of M. tuberculosis as well as its intracellular trafficking. What we propose here is a population-based, multi-parametric analysis pipeline that can be used to monitor the intracellular fate of M. tuberculosis and the dynamics of cellular events such as phagosomal maturation (acidification and permeabilization), zinc poisoning system or lipid body accumulation. Such analysis allows the quantification of biological events considering the host-pathogen interplay and may thus be derived to other intracellular pathogens. © 2017 International Society for Advancement of Cytometry.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28698636,

title = {Standardized Nanomechanical Atomic Force Microscopy Procedure (SNAP) for Measuring Soft and Biological Samples},

author = {Hermann Schillers and Carmela Rianna and Jens Schäpe and Tomas Luque and Holger Doschke and Mike Wälte and Juan José Uriarte and Noelia Campillo and Georgios P A Michanetzis and Justyna Bobrowska and Andra Dumitru and Elena T Herruzo and Simone Bovio and Pierre Parot and Massimiliano Galluzzi and Alessandro Podestà and Luca Puricelli and Simon Scheuring and Yannis Missirlis and Ricardo Garcia and Michael Odorico and Jean-Marie Teulon and Frank Lafont and Malgorzata Lekka and Felix Rico and Annafrancesca Rigato and Jean-Luc Pellequer and Hans Oberleithner and Daniel Navajas and Manfred Radmacher},

doi = {10.1038/s41598-017-05383-0},

issn = {2045-2322},

year  = {2017},

date = {2017-01-01},

journal = {Sci Rep},

volume = {7},

number = {1},

pages = {5117},

abstract = {We present a procedure that allows a reliable determination of the elastic (Young's) modulus of soft samples, including living cells, by atomic force microscopy (AFM). The standardized nanomechanical AFM procedure (SNAP) ensures the precise adjustment of the AFM optical lever system, a prerequisite for all kinds of force spectroscopy methods, to obtain reliable values independent of the instrument, laboratory and operator. Measurements of soft hydrogel samples with a well-defined elastic modulus using different AFMs revealed that the uncertainties in the determination of the deflection sensitivity and subsequently cantilever's spring constant were the main sources of error. SNAP eliminates those errors by calculating the correct deflection sensitivity based on spring constants determined with a vibrometer. The procedure was validated within a large network of European laboratories by measuring the elastic properties of gels and living cells, showing that its application reduces the variability in elastic moduli of hydrogels down to 1%, and increased the consistency of living cells elasticity measurements by a factor of two. The high reproducibility of elasticity measurements provided by SNAP could improve significantly the applicability of cell mechanics as a quantitative marker to discriminate between cell types and conditions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28484683,

title = {Alterations of the  Replicative Vacuole Membrane Integrity and Interplay with the Autophagy Pathway},

author = {María E Mansilla Pareja and Antonino Bongiovanni and Frank Lafont and María I Colombo},

doi = {10.3389/fcimb.2017.00112},

issn = {2235-2988},

year  = {2017},

date = {2017-01-01},

journal = {Front Cell Infect Microbiol},

volume = {7},

pages = {112},

abstract = {, the etiologic agent of Q fever, is a Gram-negative obligate intracellular bacterium. It has been previously described that both the endocytic and autophagic pathways contribute to the  replicative vacuole (CRV) generation. Galectins are β-galactoside-binding lectins that accumulate in the cytosol before being secreted via a non-conventional secretory pathway. It has been shown that Galectin-3, -8, -9 monitor bacteria vacuolar rupture and endosomal and lysosomal loss of membrane integrity through binding of host glycans exposed in the cytoplasm after membrane damage. Using microinjection of fluorescence-coupled dextrans, a FRET assay, and galectins distribution, we demonstrate that  infection actually result in transient phagosomal/CRV membrane damage in a Dot/Icm-dependent manner. We also show the association of different adaptor molecules involved in autophagy and of LC3 to the limiting membrane of the CRV. Moreover, we show that upon autophagy inhibition, the proportion of CRVs labeled with galectins and less acidified increases which is associated with bacteria replication impairment. Based on these observations, we propose that autophagy can facilitate resealing of intracellular damaged membranes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28112163,

title = {Developmental Expression of 4-Repeat-Tau Induces Neuronal Aneuploidy in Drosophila Tauopathy Models},

author = {Nicolas Malmanche and Pierre Dourlen and Marc Gistelinck and Florie Demiautte and Nichole Link and Cloé Dupont and Lies Vanden Broeck and Elisabeth Werkmeister and Philippe Amouyel and Antonino Bongiovanni and Hélène Bauderlique and Dieder Moechars and Anne Royou and Hugo J Bellen and Frank Lafont and Patrick Callaerts and Jean-Charles Lambert and Bart Dermaut},

doi = {10.1038/srep40764},

issn = {2045-2322},

year  = {2017},

date = {2017-01-01},

journal = {Sci Rep},

volume = {7},

pages = {40764},

abstract = {Tau-mediated neurodegeneration in Alzheimer's disease and tauopathies is generally assumed to start in a normally developed brain. However, several lines of evidence suggest that impaired Tau isoform expression during development could affect mitosis and ploidy in post-mitotic differentiated tissue. Interestingly, the relative expression levels of Tau isoforms containing either 3 (3R-Tau) or 4 repeats (4R-Tau) play an important role both during brain development and neurodegeneration. Here, we used genetic and cellular tools to study the link between 3R and 4R-Tau isoform expression, mitotic progression in neuronal progenitors and post-mitotic neuronal survival. Our results illustrated that the severity of Tau-induced adult phenotypes depends on 4R-Tau isoform expression during development. As recently described, we observed a mitotic delay in 4R-Tau expressing cells of larval eye discs and brains. Live imaging revealed that the spindle undergoes a cycle of collapse and recovery before proceeding to anaphase. Furthermore, we found a high level of aneuploidy in post-mitotic differentiated tissue. Finally, we showed that overexpression of wild type and mutant 4R-Tau isoform in neuroblastoma SH-SY5Y cell lines is sufficient to induce monopolar spindles. Taken together, our results suggested that neurodegeneration could be in part linked to neuronal aneuploidy caused by 4R-Tau expression during brain development.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27064065,

title = {Unconventional endosome-like compartment and retromer complex in Toxoplasma gondii govern parasite integrity and host infection},

author = {Lamba Omar Sangaré and Tchilabalo Dilezitoko Alayi and Benoit Westermann and Agnes Hovasse and Fabien Sindikubwabo and Isabelle Callebaut and Elisabeth Werkmeister and Frank Lafont and Christian Slomianny and Mohamed-Ali Hakimi and Alain Van Dorsselaer and Christine Schaeffer-Reiss and Stanislas Tomavo},

doi = {10.1038/ncomms11191},

issn = {2041-1723},

year  = {2016},

date = {2016-04-01},

journal = {Nat Commun},

volume = {7},

pages = {11191},

abstract = {Membrane trafficking pathways play critical roles in Apicomplexa, a phylum of protozoan parasites that cause life-threatening diseases worldwide. Here we report the first retromer-trafficking interactome in Toxoplasma gondii. This retromer complex includes a trimer Vps35-Vps26-Vps29 core complex that serves as a hub for the endosome-like compartment and parasite-specific proteins. Conditional ablation of TgVps35 reveals that the retromer complex is crucial for the biogenesis of secretory organelles and for maintaining parasite morphology. We identify TgHP12 as a parasite-specific and retromer-associated protein with functions unrelated to secretory organelle formation. Furthermore, the major facilitator superfamily homologue named TgHP03, which is a multiple spanning and ligand transmembrane transporter, is maintained at the parasite membrane by retromer-mediated endocytic recycling. Thus, our findings highlight that both evolutionarily conserved and unconventional proteins act in concert in T. gondii by controlling retrograde transport that is essential for parasite integrity and host infection. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid26620082,

title = {High potential of adhesion to biotic and abiotic surfaces by opportunistic Staphylococcus aureus strains isolated from orthodontic appliances},

author = {Abderrahmen Merghni and Mouna Ben Nejma and Ines Dallel and Samir Tobji and Adel Ben Amor and Sébastien Janel and Frank Lafont and Mahjoub Aouni and Maha Mastouri},

doi = {10.1016/j.micpath.2015.11.009},

issn = {1096-1208},

year  = {2016},

date = {2016-02-01},

journal = {Microb Pathog},

volume = {91},

pages = {61--67},

abstract = {Orthodontic and other oral appliances act as reservoir of opportunistic pathogens that can easily become resistant to antibiotics and cause systemic infections. The aim of this study was to investigate the ability of Staphylococcus aureus strains isolated from healthy patients with orthodontic appliances, to adhere to biotic (HeLa cells) and abiotic surfaces (polystyrene and dental alloy). Adhesive ability to polystyrene was tested by crystal violet staining and quantitative biofilm production on dental alloy surfaces was evaluated by MTT reduction assay. In addition, the presence of icaA and icaD genes was achieved by polymerase chain reaction (PCR). Qualitative biofilm production revealed that 70.6% of strains were slime producers. The metabolic activity of S. aureus biofilms on dental alloy surfaces was high and did not differ between tested strains. Moreover, all the isolates were adhesive to HeLa cells and 94% of them harbor icaA and icaD genes. Considerable adhesion and internalization capacity to the epithelial HeLa cells and strong biofilm production abilities together, with a high genotypic expression of icaA/icaD genes are an important equipment of S. aureus to colonize orthodontic appliances and eventually to disseminate towards other body areas.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27448494,

title = {Manipulation of host membranes by the bacterial pathogens Listeria, Francisella, Shigella and Yersinia},

author = {Javier Pizarro-Cerdá and Alain Charbit and Jost Enninga and Frank Lafont and Pascale Cossart},

doi = {10.1016/j.semcdb.2016.07.019},

issn = {1096-3634},

year  = {2016},

date = {2016-01-01},

journal = {Semin Cell Dev Biol},

volume = {60},

pages = {155--167},

abstract = {Bacterial pathogens display an impressive arsenal of molecular mechanisms that allow survival in diverse host niches. Subversion of plasma membrane and cytoskeletal functions are common themes associated to infection by both extracellular and intracellular pathogens. Moreover, intracellular pathogens modify the structure/stability of their membrane-bound compartments and escape degradation from phagocytic or autophagic pathways. Here, we review the manipulation of host membranes by Listeria monocytogenes, Francisella tularensis, Shigella flexneri and Yersinia spp. These four bacterial model pathogens exemplify generalized strategies as well as specific features observed during bacterial infection processes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid27046256,

title = {TRANSAUTOPHAGY: European network for multidisciplinary research and translation of autophagy knowledge},

author = {Caty Casas and Patrice Codogno and Marcello Pinti and Henri Batoko and María Morán and Tassula Proikas-Cezanne and Fulvio Reggiori and Agnieszka Sirko and María S Soengas and Guillermo Velasco and Frank Lafont and Jon Lane and Mathias Faure and Andrea Cossarizza},

doi = {10.1080/15548627.2016.1140294},

issn = {1554-8635},

year  = {2016},

date = {2016-01-01},

journal = {Autophagy},

volume = {12},

number = {3},

pages = {614--617},

abstract = {A collaborative consortium, named "TRANSAUTOPHAGY," has been created among European research groups, comprising more than 150 scientists from 21 countries studying diverse branches of basic and translational autophagy. The consortium was approved in the framework of the Horizon 2020 Program in November 2015 as a COST Action of the European Union (COST means: CO-operation in Science and Technology), and will be sponsored for 4 years. TRANSAUTOPHAGY will form an interdisciplinary platform for basic and translational researchers, enterprises and stakeholders of diverse disciplines (including nanotechnology, bioinformatics, physics, chemistry, biology and various medical disciplines). TRANSAUTOPHAGY will establish 5 different thematic working groups, formulated to cooperate in research projects, share ideas, and results through workshops, meetings and short term exchanges of personnel (among other initiatives). TRANSAUTOPHAGY aims to generate breakthrough multidisciplinary knowledge about autophagy regulation, and to boost translation of this knowledge into biomedical and biotechnological applications. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{MERGHNI2016323,

title = {Quantification of Staphylococcus aureus adhesion forces on various dental restorative materials using atomic force microscopy},

author = {Abderrahmen Merghni and Dorra Kammoun and Hajer Hentati and Sébastien Janel and Michka Popoff and Frank Lafont and Mahjoub Aouni and Maha Mastouri},

url = {https://www.sciencedirect.com/science/article/pii/S0169433216308224},

doi = {https://doi.org/10.1016/j.apsusc.2016.04.072},

issn = {0169-4332},

year  = {2016},

date = {2016-01-01},

journal = {Applied Surface Science},

volume = {379},

pages = {323-330},

abstract = {In the oral cavity dental restorative biomaterials can act as a reservoir for infection with opportunistic Staphylococcus aureus pathogen, which can lead to the occurrence of secondary caries and treatment failures. Our aim was to evaluate the adhesion forces by S. aureus on four dental restorative biomaterials and to correlate this finding to differences in specific surface characteristics. Additionally, the influence of salivary conditioning films in exerted adhesion forces was investigated. The substrate hydrophobicity was measured by goniometer and the surface free energy was calculated using the equilibrium advancing contact angle values of water, formamide, and diiodomethane on the tested surfaces. The surface roughness was determined using atomic force microscope (AFM). Additionally, cell force spectroscopy was achieved to quantify the forces that drive cell-substrate interactions. S. aureus bacterium exerted a considerable adhesion forces on various dental restorative materials, which decreased in the presence of saliva conditioning film. The influence of the surface roughness and free energy in initial adhesion appears to be more important than the effect of hydrophobicity, either in presence or absence of saliva coating. Hence, control of surface properties of dental restorative biomaterials is of crucial importance in preventing the attachment and subsequent the biofilm formation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid26055540,

title = {Assessment of adhesion, invasion and cytotoxicity potential of oral Staphylococcus aureus strains},

author = {Abderrahmen Merghni and Mouna Ben Nejma and Imen Helali and Hajer Hentati and Antonino Bongiovanni and Frank Lafont and Mahjoub Aouni and Maha Mastouri},

doi = {10.1016/j.micpath.2015.05.010},

issn = {1096-1208},

year  = {2015},

date = {2015-09-01},

journal = {Microb Pathog},

volume = {86},

pages = {1--9},

abstract = {The oral cavity is regarded as a relevant site for Staphylococcus aureus colonization. However, characterization of virulence mechanisms of oral S. aureus remains to be uncovered. In this study, twenty one S. aureus strains isolated from the oral cavity of Tunisian patients were screened for adherence, invasion and cytotoxicity against HeLa cells. In addition, the presence of adhesins (icaA, icaD, can, fnbA and fnbB) and α-hemolysin (hla) genes in each strain was achieved by polymerase chain reaction (PCR). Our finding revealed that oral S. aureus strains were able to adhere and invade epithelial cells, with variable degrees (P < 0.05). Moreover they exhibited either low (23.8%) or moderate (76.2%) cytotoxic effects. In addition 76.2% of strains were icaA and icaD positive and 90.5% harbor both the fnbA and the fnbB gene. While the cna gene was detected in 12 strains (57.2%). Furthermore, the hla gene encoding the α-toxin was found in 52.4% of the isolates. All these virulence factors give to S. aureus the right qualities to become a redoubtable pathogen associated to oral infections. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid25916824,

title = {Interplay between troponin T phosphorylation and O-N-acetylglucosaminylation in ischaemic heart failure},

author = {Emilie Dubois-Deruy and Aude Belliard and Paul Mulder and Marion Bouvet and Caroline Smet-Nocca and Sébastien Janel and Frank Lafont and Olivia Beseme and Philippe Amouyel and Vincent Richard and Florence Pinet},

doi = {10.1093/cvr/cvv136},

issn = {1755-3245},

year  = {2015},

date = {2015-07-01},

journal = {Cardiovasc Res},

volume = {107},

number = {1},

pages = {56--65},

abstract = {AIMS: Previous studies have reported that decreased serine 208 phosphorylation of troponin T (TnTpSer208) is associated with ischaemic heart failure (HF), but the molecular mechanisms and functional consequences of these changes are unknown. The aim of this study was to characterize the balance between serine phosphorylation and O-N-acetylglucosaminylation (O-GlcNAcylation) of TnT in HF, its mechanisms, and the consequences of modulating these post-translational modifications.



METHODS AND RESULTS: Decreased TnTpSer208 levels in the left ventricles of HF male Wistar rats were associated with reduced expression of PKCε but not of other cardiac PKC isoforms. In both isolated perfused rat hearts and cultured neonatal cardiomyocytes, the PKCε inhibitor εV1-2 decreased TnTpSer208 and simultaneously decreased cardiac contraction in isolated hearts and beating amplitude in neonatal cardiomyocytes (measured by atomic force microscopy). Down-regulating PKCε by silencing RNA (siRNA) also reduced TnTpSer208 in these cardiomyocytes, and PKCε-/- mice had lower TnTpSer208 levels than the wild-type. In parallel, HF increased TnT O-GlcNAcylation via both increased O-GlcNAc transferase and decreased O-GlcNAcase activity. Increasing O-GlcNAcylation (via O-GlcNAcase inhibition with Thiamet G) decreased TnTpSer208 in isolated hearts, while reducing O-GlcNAcylation (O-GlcNAc transferase siRNA) increased TnTpSer208 in neonatal cardiomyocytes. Mass spectrometry and NMR analysis identified O-GlcNAcylation of TnT on Ser190.



CONCLUSION: These data demonstrate interplay between Ser208 phosphorylation and Ser190 O-GlcNAcylation of TnT in ischaemic HF, linked to decreased activity of both PKCε and O-GlcNAcase and increased O-GlcNAc transferase activity. Modulation of these post-translational modifications of TnT may be a new therapeutic strategy in HF.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid25667106,

title = {Structured illumination microscopy and correlative microscopy to study autophagy},

author = {Laure-Anne Ligeon and Nicolas Barois and Elisabeth Werkmeister and Antonino Bongiovanni and Frank Lafont},

doi = {10.1016/j.ymeth.2015.01.017},

issn = {1095-9130},

year  = {2015},

date = {2015-03-01},

journal = {Methods},

volume = {75},

pages = {61--68},

abstract = {Autophagy is a predominant eukaryotic mechanism for the engulfment of "portions" of cytoplasm allowing their degradation to recycle metabolites. The autophagy is ubiquitous among the life kingdom revealing the importance of this pathway that appears more complex than previously thought. Several reviews have already addressed how to monitor this pathway and have highlighted the existence of new routes such as the LC3-associated phagocytosis (LAP) and the non-canonical autophagy. The principal difference between autophagosomes and LAP vacuoles is that the former has two limiting membranes positives for LC3 whereas the latter has one. Herein, we propose to emphasize the use of correlative light electron microscopy (CLEM) to answer some autophagy's related questions. The structured illumination microscopy (SIM) relatively easy to implement allows to better observe the Atg proteins recruitment and localization during the autophagy process. While LC3 recruitment is performed using light microscopy the ultrastructural morphological analysis of LC3-vacuoles is ascertained by electron microscopy. Hence, these combined and correlated approaches allow to tackle the LAP vs. autophagosome issue.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{C5PY00197H,

title = {Quantifying bacterial adhesion on antifouling polymer brushes via single-cell force spectroscopy},

author = {Cesar Rodriguez-Emmenegger and Sébastien Janel and Andres Santos Pereira and Michael Bruns and Frank Lafont},

url = {http://dx.doi.org/10.1039/C5PY00197H},

doi = {10.1039/C5PY00197H},

year  = {2015},

date = {2015-01-01},

journal = {Polym. Chem.},

volume = {6},

issue = {31},

pages = {5740-5751},

publisher = {The Royal Society of Chemistry},

abstract = {Bacterial adhesion poses serious problems in food safety and biomedical applications. Antifouling polymer brushes have been shown to be effective as surface modifications to prevent biofilm formation from pathogenic bacteria. In this work, the adhesion of Yersinia pseudotuberculosis on seven types of brushes is examined by single-cell force spectroscopy. The brushes, known to possess excellent resistance to protein adsorption, greatly reduced the maximum force and the work required to detach the bacterium.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid25046114,

title = {Role of VAMP3 and VAMP7 in the commitment of Yersinia pseudotuberculosis to LC3-associated pathways involving single- or double-membrane vacuoles},

author = {Laure-Anne Ligeon and Kevin Moreau and Nicolas Barois and Antonino Bongiovanni and Delphine-Armelle Lacorre and Elisabeth Werkmeister and Véronique Proux-Gillardeaux and Thierry Galli and Frank Lafont},

doi = {10.4161/auto.29411},

issn = {1554-8635},

year  = {2014},

date = {2014-09-01},

journal = {Autophagy},

volume = {10},

number = {9},

pages = {1588--1602},

abstract = {Yersinia pseudotuberculosis can replicate inside macrophages by hijacking autophagy and blocking autophagosome acidification. In bone marrow-derived macrophages, the bacteria are mainly observed inside double-membrane vacuoles positive for LC3, a hallmark of autophagy. Here, we address the question of the membrane traffic during internalization of Yersinia investigating the role of vesicle- associated membrane proteins (VAMPs). First, we show that as in epithelial cells, Yersinia pseudotuberculosis replicates mainly in nonacidic LC3-positive vacuoles. Second, in these cells, we unexpectedly found that VAMP3 localizes preferentially to Yersinia-containing vacuoles (YCVs) with single membranes using correlative light-electron microscopy. Third, we reveal the precise kinetics of VAMP3 and VAMP7 association with YCVs positive for LC3. Fourth, we show that VAMP7 knockdown alters LC3's association with single-and multimembrane-YCVs. Finally, in uninfected epithelial cells stimulated for autophagy, VAMP3 overexpression and knockdown led respectively to a lower and higher number of double-membrane, LC3-positive vesicles. Hence, our results highlight the role that VAMPs play in selection of the pathways leading to generation of ultrastructurally different LC3 compartments and pave the way for determining the full set of docking and fusion proteins involved in Yersinia pseudotuberculosis' intravesicular life cycle. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid24880614,

title = {Pathogenic Neisseria meningitidis utilizes CD147 for vascular colonization},

author = {Sandra C Bernard and Nandi Simpson and Olivier Join-Lambert and Christian Federici and Marie-Pierre Laran-Chich and Nawal Maïssa and Haniaa Bouzinba-Ségard and Philippe C Morand and Fabrice Chretien and Saïd Taouji and Eric Chevet and Sébastien Janel and Frank Lafont and Mathieu Coureuil and Audrey Segura and Florence Niedergang and Stefano Marullo and Pierre-Olivier Couraud and Xavier Nassif and Sandrine Bourdoulous},

doi = {10.1038/nm.3563},

issn = {1546-170X},

year  = {2014},

date = {2014-07-01},

journal = {Nat Med},

volume = {20},

number = {7},

pages = {725--731},

abstract = {Neisseria meningitidis is a cause of meningitis epidemics worldwide and of rapidly progressing fatal septic shock. A crucial step in the pathogenesis of invasive meningococcal infections is the adhesion of bloodborne meningococci to both peripheral and brain endothelia, leading to major vascular dysfunction. Initial adhesion of pathogenic strains to endothelial cells relies on meningococcal type IV pili, but the endothelial receptor for bacterial adhesion remains unknown. Here, we report that the immunoglobulin superfamily member CD147 (also called extracellular matrix metalloproteinase inducer (EMMPRIN) or Basigin) is a critical host receptor for the meningococcal pilus components PilE and PilV. Interfering with this interaction potently inhibited the primary attachment of meningococci to human endothelial cells in vitro and prevented colonization of vessels in human brain tissue explants ex vivo and in humanized mice in vivo. These findings establish the molecular events by which meningococci target human endothelia, and they open new perspectives for treatment and prevention of meningococcus-induced vascular dysfunctions. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid25484092,

title = {Autophagy in osteoblasts is involved in mineralization and bone homeostasis},

author = {Marie Nollet and Sabine Santucci-Darmanin and Véronique Breuil and Rasha Al-Sahlanee and Chantal Cros and Majlinda Topi and David Momier and Michel Samson and Sophie Pagnotta and Laurence Cailleteau and Séverine Battaglia and Delphine Farlay and Romain Dacquin and Nicolas Barois and Pierre Jurdic and Georges Boivin and Dominique Heymann and Frank Lafont and Shi Shou Lu and David W Dempster and Georges F Carle and Valérie Pierrefite-Carle},

doi = {10.4161/auto.36182},

issn = {1554-8635},

year  = {2014},

date = {2014-01-01},

journal = {Autophagy},

volume = {10},

number = {11},

pages = {1965--1977},

abstract = {Bone remodeling is a tightly controlled mechanism in which osteoblasts (OB), the cells responsible for bone formation, osteoclasts (OC), the cells specialized for bone resorption, and osteocytes, the multifunctional mechanosensing cells embedded in the bone matrix, are the main actors. Increased oxidative stress in OB, the cells producing and mineralizing bone matrix, has been associated with osteoporosis development but the role of autophagy in OB has not yet been addressed. This is the goal of the present study. We first show that the autophagic process is induced in OB during mineralization. Then, using knockdown of autophagy-essential genes and OB-specific autophagy-deficient mice, we demonstrate that autophagy deficiency reduces mineralization capacity. Moreover, our data suggest that autophagic vacuoles could be used as vehicles in OB to secrete apatite crystals. In addition, autophagy-deficient OB exhibit increased oxidative stress and secretion of the receptor activator of NFKB1 (TNFSF11/RANKL), favoring generation of OC, the cells specialized in bone resorption. In vivo, we observed a 50% reduction in trabecular bone mass in OB-specific autophagy-deficient mice. Taken together, our results show for the first time that autophagy in OB is involved both in the mineralization process and in bone homeostasis. These findings are of importance for mineralized tissues which extend from corals to vertebrates and uncover new therapeutic targets for calcified tissue-related metabolic pathologies. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid23652193,

title = {Pathogen-induced autophagy signaling in innate immunity},

author = {Mathias Faure and Frank Lafont},

doi = {10.1159/000350918},

issn = {1662-8128},

year  = {2013},

date = {2013-01-01},

journal = {J Innate Immun},

volume = {5},

number = {5},

pages = {456--470},

abstract = {Innate immunity induces rapid responses to fight invading pathogens. To eliminate intracellular bacteria or viruses, innate cellular responses lead to the production of nuclear factor-κB-dependent inflammatory cytokines, inflammasome activation, type I interferon synthesis, and/or eventually death of the infected cells. Autophagy emerged as another component of innate immunity, as it offers an immediate autonomous cell defense mechanism by degrading intracellular pathogens. In addition, autophagy participates in the regulation of immune and inflammatory cell responses. Instead of providing a comprehensive status of the art that has already been addressed elsewhere, we chose to highlight some recent issues brought up in the field. },

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid23003307,

title = {Cellular dewetting: opening of macroapertures in endothelial cells},

author = {David Gonzalez-Rodriguez and Madhavi P Maddugoda and Caroline Stefani and Sebastien Janel and Frank Lafont and Damien Cuvelier and Emmanuel Lemichez and Françoise Brochard-Wyart},

doi = {10.1103/PhysRevLett.108.218105},

issn = {1079-7114},

year  = {2012},

date = {2012-05-01},

journal = {Phys Rev Lett},

volume = {108},

number = {21},

pages = {218105},

abstract = {Pathogenic bacteria can cross from blood vessels to host tissues by opening transendothelial cell macroapertures (TEMs). To induce TEM opening, bacteria intoxicate endothelial cells with proteins that disrupt the contractile cytoskeletal network. Cell membrane tension is no longer resisted by contractile fibers, leading to the opening of TEMs. Here we model the opening of TEMs as a new form of dewetting. While liquid dewetting is irreversible, we show that cellular dewetting is transient. Our model predicts the minimum radius for hole nucleation, the maximum TEM size, and the dynamics of TEM opening, in good agreement with experimental data. The physical model is then coupled with biological experimental data to reveal that the protein missing in metastasis (MIM) controls the line tension at the rim of the TEM and opposes its opening.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{https://doi.org/10.1002/aic.13747,

title = {A combined computational fluid dynamics (CFD) and experimental approach to quantify the adhesion force of bacterial cells attached to a plane surface},

author = {Benjamin Boulbene and Jérôme Morchain and Muriel Mercier Bonin and Sébastien Janel and Frank Lafont and Philippe Schmitz},

url = {https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/aic.13747},

doi = {https://doi.org/10.1002/aic.13747},

year  = {2012},

date = {2012-01-01},

journal = {AIChE Journal},

volume = {58},

number = {12},

pages = {3614-3624},

abstract = {Abstract A three-dimensional model is developed to study the laminar shear flow past a bacterial cell attached to a plane surface. The induced hydrodynamic forces and torque exerted on the cell are computed to clarify the prevailing mechanisms involved in the detachment of model bacteria. Results are discussed in terms of drag and torque magnitude as a function of the angles defining the orientation of the cell. It is shown that reorientation and rolling of spheroid-shaped cells are favored. It is also confirmed that rod-shaped cells would tend to lie on the surface and become aligned with the flow. The model is used to quantify the adhesion force of spheroid Bacillus cereus spores to stainless steel, deduced from previously described experiments in a shear stress flow chamber. The magnitude of the predicted adhesion force is close to that obtained using atomic force microscopy under similar experimental conditions. © 2012 American Institute of Chemical Engineers AIChE J, 2012},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid22100162,

title = {cAMP signaling by anthrax edema toxin induces transendothelial cell tunnels, which are resealed by MIM via Arp2/3-driven actin polymerization},

author = {Madhavi P Maddugoda and Caroline Stefani and David Gonzalez-Rodriguez and Juha Saarikangas and Stéphanie Torrino and Sebastien Janel and Patrick Munro and Anne Doye and François Prodon and Michel Aurrand-Lions and Pierre L Goossens and Frank Lafont and Patricia Bassereau and Pekka Lappalainen and Françoise Brochard and Emmanuel Lemichez},

doi = {10.1016/j.chom.2011.09.014},

issn = {1934-6069},

year  = {2011},

date = {2011-11-01},

journal = {Cell Host Microbe},

volume = {10},

number = {5},

pages = {464--474},

abstract = {RhoA-inhibitory bacterial toxins, such as Staphylococcus aureus EDIN toxin, induce large transendothelial cell macroaperture (TEM) tunnels that rupture the host endothelium barrier and promote bacterial dissemination. Host cells repair these tunnels by extending actin-rich membrane waves from the TEM edges. We reveal that cyclic-AMP signaling produced by Bacillus anthracis edema toxin (ET) also induces TEM formation, which correlates with increased vascular permeability. We show that ET-induced TEM formation resembles liquid dewetting, a physical process of nucleation and growth of holes within a thin liquid film. We also identify the cellular mechanisms of tunnel closure and reveal that the I-BAR domain protein Missing in Metastasis (MIM) senses de novo membrane curvature generated by the TEM, accumulates at the TEM edge, and triggers Arp2/3-dependent actin polymerization, which induces actin-rich membrane waves that close the TEM. Thus, the balance between ET-induced TEM formation and resealing likely determines the integrity of the host endothelium barrier.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid21740497,

title = {Ubiquitylation and autophagy in the control of bacterial infections and related inflammatory responses},

author = {Laure-Anne Ligeon and Nassima Temime-Smaali and Frank Lafont},

doi = {10.1111/j.1462-5822.2011.01628.x},

issn = {1462-5822},

year  = {2011},

date = {2011-09-01},

journal = {Cell Microbiol},

volume = {13},

number = {9},

pages = {1303--1311},

abstract = {The ubiquitin proteasome system and autophagy constitute key signalling pathways in the host response to infection. The identification of adaptors linking the two pathways has prompted a re-examination of the latter's involvement in inflammatory reactions and the clearance of bacteria. The ubiquitin-autophagy pathway is a preferred target for effectors from pathogens that seek to exploit and evade the host defence mechanisms. A number of new players and signalling nodes have recently been identified. Here, we discuss these new insights into the host's control of bacterial infection.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid21504731,

title = {A role for septins in the interaction between the Listeria monocytogenes INVASION PROTEIN InlB and the Met receptor},

author = {Serge Mostowy and Sébastien Janel and Claire Forestier and Charles Roduit and Sandor Kasas and Javier Pizarro-Cerdá and Pascale Cossart and Frank Lafont},

doi = {10.1016/j.bpj.2011.02.040},

issn = {1542-0086},

year  = {2011},

date = {2011-04-01},

journal = {Biophys J},

volume = {100},

number = {8},

pages = {1949--1959},

abstract = {Septins are conserved GTPases that form filaments and are required for cell division. During interphase, septin filaments associate with cellular membrane and cytoskeleton networks, yet the functional significance of these associations have, to our knowledge, remained unknown. We recently discovered that different septins, SEPT2 and SEPT11, regulate the InlB-mediated entry of Listeria monocytogenes into host cells. Here we address the role of SEPT2 and SEPT11 in the InlB-Met interactions underlying Listeria invasion to explore how septins modulate surface receptor function. We observed that differences in InlB-mediated Listeria entry correlated with differences in Met surface expression caused by septin depletion. Using atomic force microscopy on living cells, we show that septin depletion significantly reduced the unbinding force of InlB-Met interaction and the viscosity of membrane tethers at locations where the InlB-Met interaction occurs. Strikingly, the same order of difference was observed for cells in which the actin cytoskeleton was disrupted. Consistent with a proposed role of septins in association with the actin cytoskeleton, we show that cell elasticity is decreased upon septin or actin inactivation. Septins are therefore likely to participate in anchorage of the Met receptor to the actin cytoskeleton, and represent a critical determinant in surface receptor function.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid22205992,

title = {Clag9 is not essential for PfEMP1 surface expression in non-cytoadherent Plasmodium falciparum parasites with a chromosome 9 deletion},

author = {Adéla Nacer and Emeric Roux and Sébastien Pomel and Christine Scheidig-Benatar and Hiroshi Sakamoto and Frank Lafont and Artur Scherf and Denise Mattei},

doi = {10.1371/journal.pone.0029039},

issn = {1932-6203},

year  = {2011},

date = {2011-01-01},

journal = {PLoS One},

volume = {6},

number = {12},

pages = {e29039},

abstract = {BACKGROUND: The expression of the clonally variant virulence factor PfEMP1 mediates the sequestration of Plasmodium falciparum infected erythrocytes in the host vasculature and contributes to chronic infection. Non-cytoadherent parasites with a chromosome 9 deletion lack clag9, a gene linked to cytoadhesion in previous studies. Here we present new clag9 data that challenge this view and show that surface the non-cytoadherence phenotype is linked to the expression of a non-functional PfEMP1.



METHODOLOGY/PRINCIPAL FINDINGS: Loss of adhesion in P. falciparum D10, a parasite line with a large chromosome 9 deletion, was investigated. Surface iodination analysis of non-cytoadherent D10 parasites and COS-7 surface expression of the CD36-binding PfEMP1 CIDR1α domain were performed and showed that these parasites express an unusual trypsin-resistant, non-functional PfEMP1 at the erythrocyte surface. However, the CIDR1α domain of this var gene expressed in COS-7 cells showed strong binding to CD36. Atomic Force Microscopy showed a slightly modified D10 knob morphology compared to adherent parasites. Trafficking of PfEMP1 and KAHRP remained functional in D10. We link the non-cytoadherence phenotype to a chromosome 9 breakage and healing event resulting in the loss of 25 subtelomeric genes including clag9. In contrast to previous studies, knockout of the clag9 gene from 3D7 did not interfere with parasite adhesion to CD36.



CONCLUSIONS/SIGNIFICANCE: Our data show the surface expression of non-functional PfEMP1 in D10 strongly indicating that genes other than clag9 deleted from chromosome 9 are involved in this virulence process possibly via post-translational modifications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid21077843,

title = {How ubiquitination and autophagy participate in the regulation of the cell response to bacterial infection},

author = {Nicolas Dupont and Nassima Temime-Smaali and Frank Lafont},

doi = {10.1042/BC20100101},

issn = {1768-322X},

year  = {2010},

date = {2010-12-01},

journal = {Biol Cell},

volume = {102},

number = {12},

pages = {621--634},

abstract = {Bacterial infection relies on the micro-organism's ability to orchestrate the host's cell signalling such that the immune response is not activated. Conversely, the host cell has dedicated signalling pathways for coping with intrusions by pathogens. The autophagy of foreign micro-organisms (known as xenophagy) has emerged as one of the most powerful of these pathways, although the triggering mode remains largely unknown. In the present paper, we discuss the role that certain post-translational modifications (primarily ubiquitination) may play in the activation of xenophagy and how some bacteria have evolved mechanisms to subvert or hijack this process. In particular, we address the role played by P62/SQSTM1 (sequestosome 1). Finally, we discuss how autophagy can be subverted to eliminate bacteria-induced danger signals.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid20709289,

title = {Autophagy employs a new DAGger against bacteria},

author = {Frank Lafont},

doi = {10.1016/j.chom.2010.07.009},

issn = {1934-6069},

year  = {2010},

date = {2010-08-01},

journal = {Cell Host Microbe},

volume = {8},

number = {2},

pages = {129--130},

abstract = {Autophagy can orchestrate innate immune responses to bacterial infection by targeting invading pathogens for lysosomal degradation. In this issue of Cell Host & Microbe, Shahnazari et al. (2010) unveil the role played by the diacylglycerol-PKC pathway in the routing of intracellular Salmonella to autophagy.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid20180800,

title = {Autophagosomes can support Yersinia pseudotuberculosis replication in macrophages},

author = {Kevin Moreau and Sandra Lacas-Gervais and Naonobu Fujita and Florent Sebbane and Tamotsu Yoshimori and Michel Simonet and Frank Lafont},

doi = {10.1111/j.1462-5822.2010.01456.x},

issn = {1462-5822},

year  = {2010},

date = {2010-08-01},

journal = {Cell Microbiol},

volume = {12},

number = {8},

pages = {1108--1123},

abstract = {Yersinia pseudotuberculosis is able to replicate inside macrophages. However, the intracellular trafficking of the pathogen after its entry into the macrophage remains poorly understood. Using in vitro infected bone marrow-derived macrophages, we show that Y. pseudotuberculosis activates the autophagy pathway. Host cell autophagosomes subverted by bacteria do not become acidified and sustain bacteria replication. Moreover, we report that autophagy inhibition correlated with bacterial trafficking inside an acidic compartment. This study indicates that Y. pseudotuberculosis hijacks the autophagy pathway for its replication and also opens up new opportunities for deciphering the molecular basis of the host cell signalling response to intracellular Yersinia infection.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid19951367,

title = {Galectin-3, a marker for vacuole lysis by invasive pathogens},

author = {Irit Paz and Martin Sachse and Nicolas Dupont and Joelle Mounier and Cecilia Cederfur and Jost Enninga and Hakon Leffler and Francoise Poirier and Marie-Christine Prevost and Frank Lafont and Philippe Sansonetti},

doi = {10.1111/j.1462-5822.2009.01415.x},

issn = {1462-5822},

year  = {2010},

date = {2010-04-01},

journal = {Cell Microbiol},

volume = {12},

number = {4},

pages = {530--544},

abstract = {Shigella bacteria invade macrophages and epithelial cells and following internalization lyse the phagosome and escape to the cytoplasm. Galectin-3, an abundant protein in macrophages and epithelial cells, belongs to a family of beta-galactoside-binding proteins, the galectins, with many proposed functions in immune response, development, differentiation, cancer and infection. Galectins are synthesized as cytosolic proteins and following non-classical secretion bind extracellular beta-galactosides. Here we analysed the localization of galectin-3 following entry of Shigella into the cytosol and detected a striking phenomenon. Very shortly after bacterial invasion, intracellular galectin-3 accumulated in structures in vicinity to internalized bacteria. By using immuno-electron microscopy analysis we identified galectin-3 in membranes localized in the phagosome and in tubules and vesicles that derive from the endocytic pathway. We also demonstrated that the binding of galectin-3 to host N-acetyllactosamine-containing glycans, was required for forming the structures. Accumulation of the structures was a type three secretion system-dependent process. More specifically, existence of structures was strictly dependent upon lysis of the phagocytic vacuole and could be shown also by Gram-positive Listeria and Salmonella sifA mutant. We suggest that galectin-3-containing structures may serve as a potential novel tool to spot vacuole lysis.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid19829050,

title = {How autophagy regulates the host cell signaling associated with the postpartum bacteria cocoon experienced as a danger signal},

author = {Nicolas Dupont and Frank Lafont},

doi = {10.4161/auto.5.8.10218},

issn = {1554-8635},

year  = {2009},

date = {2009-11-01},

journal = {Autophagy},

volume = {5},

number = {8},

pages = {1222--1223},

abstract = {Shigella, the causative agent of human bacillary dysentery, invades the host cell, rapidly breaking the phagosome and multiplying in the cytosol. Here, we summarize our recent work showing the targeting of the leftover membrane remnants to autophagy together with trapped membrane-associated signaling molecules recruited during the immediate early entry step. We suggest that this mechanism participates in the bacteria-dependent orchestration of the cell response. Moreover, we propose that this signaling node may have relevance as to how the cell interprets endomembrane damage triggered by other stimuli.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid19683680,

title = {Shigella phagocytic vacuolar membrane remnants participate in the cellular response to pathogen invasion and are regulated by autophagy},

author = {Nicolas Dupont and Sandra Lacas-Gervais and Julie Bertout and Irit Paz and Barbara Freche and Guy Tran Van Nhieu and F Gisou van der Goot and Philippe J Sansonetti and Frank Lafont},

doi = {10.1016/j.chom.2009.07.005},

issn = {1934-6069},

year  = {2009},

date = {2009-08-01},

journal = {Cell Host Microbe},

volume = {6},

number = {2},

pages = {137--149},

abstract = {Intracellular pathogens like Shigella flexneri enter host cells by phagocytosis. Once inside, the pathogen breaks the vacuolar membrane for cytosolic access. The fate and function of the vacuolar membrane remnants are not clear. Examining Shigella-infected nonmyeloid cells, we observed that proteins associated with vacuolar membrane remnants are polyubiquinated, recruit the autophagy marker LC3 and adaptor p62, and are targeted to autophagic degradation. Further, inflammasome components and caspase-1 were localized to these membranes and correlated with dampened inflammatory response and necrotic cell death. In Atg4B mutant cells in which autophagosome maturation is blocked, polyubiquitinated proteins and P62 accumulated on membrane remnants, and as in autophagy-deficient Atg5(-/-) cells, the early inflammatory and cytokine response was exacerbated. Our results suggest that host membranes, after rupture by an invading cytoplasm-targeted bacterium, contribute to the cellular responses to infection by acting as a signaling node, with autophagy playing a central role in regulating these responses.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid19619482,

title = {Stiffness tomography by atomic force microscopy},

author = {Charles Roduit and Serguei Sekatski and Giovanni Dietler and Stefan Catsicas and Frank Lafont and Sandor Kasas},

doi = {10.1016/j.bpj.2009.05.010},

issn = {1542-0086},

year  = {2009},

date = {2009-07-01},

journal = {Biophys J},

volume = {97},

number = {2},

pages = {674--677},

abstract = {The atomic force microscope is a convenient tool to probe living samples at the nanometric scale. Among its numerous capabilities, the instrument can be operated as a nano-indenter to gather information about the mechanical properties of the sample. In this operating mode, the deformation of the cantilever is displayed as a function of the indentation depth of the tip into the sample. Fitting this curve with different theoretical models permits us to estimate the Young's modulus of the sample at the indentation spot. We describe what to our knowledge is a new technique to process these curves to distinguish structures of different stiffness buried into the bulk of the sample. The working principle of this new imaging technique has been verified by finite element models and successfully applied to living cells.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}