Publications by authors named "Vanessa Lievin Le-Moal"

The intestinal microbiota (IM) plays a role in the severity of alcohol-associated liver disease. Modifying severe alcohol-associated hepatitis (AH) dysbiosis improves liver injury through tryptophan (Trp) metabolites and the aryl hydrocarbon receptor (AhR). However, Trp's effect on the IM in alcohol use disorder (AUD) patients remains unclear.

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, a protozoan parasite specific to the human genital tract, is one of the most common sexually transmitted pathogens. Its pathogenicity is strongly associated with its expression of a broad array of proteases triggering cytotoxic effects in host epithelial cells. Vaginal microbiota-associated , including those of in particular, can counteract pathogenesis, but the mechanisms involved have yet to be clarified.

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Objective: Chronic alcohol consumption is an important cause of liver-related deaths. Specific intestinal microbiota profiles are associated with susceptibility or resistance to alcoholic liver disease in both mice and humans. We aimed to identify the mechanisms by which targeting intestinal microbiota can improve alcohol-induced liver lesions.

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The parasitophorous vacuoles (PVs) that insulate Leishmania spp. in host macrophages are vacuolar compartments wherein promastigote forms differentiate into amastigote that are the replicative form of the parasite and are also more resistant to host responses. We revisited the biogenesis of tight-fitting PVs that insulate L.

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Autophagy is a catabolic recycling process by which a cell degrades its own constituents to contribute to cell homeostasis or survival. We report that the small trafficking inhibitor Retro-2 impairs microtubule-dependent vacuolar trafficking in autophagy. Retro-2 induced autophagy and promoted the dramatic cytoplasmic accumulation of large autophagosomes.

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We conducted a study to decipher the mechanism of the formation of the large communal Leishmania amazonensis-containing parasitophorous vacuole (PV) and found that the macrophage microtubule (MT) network dynamically orchestrates the intracellular lifestyle of this intracellular parasite. Physical disassembly of the MT network of macrophage-like RAW 264.7 cells or silencing of the dynein gene, encoding the MT-associated molecular motor that powers MT-dependent vacuolar movement, by siRNA resulted in most of the infected cells hosting only tight parasite-containing phagosome-like vacuoles randomly distributed throughout the cytoplasm, each insulating a single parasite.

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We aimed to analyze the strain-by-strain expression of a large panel of antimicrobial activities counteracting the virulence mechanisms of bacterial vaginosis-associated CI-1 and 594, pyelonephritis-associated CFT073, and recurrent cystitis- and preterm labor-associated IH11128 by and clinical strains, and ATCC 9857 and KS 120.1, and CTV-05 strains isolated from the cervicovaginal microbiota of healthy women. All and strains exerted antimicrobial activity by secreted lactic acid, which killed the microbial pathogens by direct contact.

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Medical countermeasures to treat biothreat agent infections require broad-spectrum therapeutics that do not induce agent resistance. A cell-based high-throughput screen (HTS) against ricin toxin combined with hit optimization allowed selection of a family of compounds that meet these requirements. The hit compound Retro-2 and its derivatives have been demonstrated to be safe in vivo in mice even at high doses.

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Experimental in vitro and in vivo studies support the hypothesis that heat-treated, lyophilized Lactobacillus acidophilus LB cells and concentrated, neutralized spent culture medium conserve the variety of pharmacological, antimicrobial activities of the live probiotic strain against several infectious agents involved in well-established acute and persistent watery diarrhoea and gastritis. Heat-treated cells and heat-stable secreted molecules trigger multiple strain-specific activities explaining the therapeutic efficacy of L. acidophilus LB.

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Leishmania spp., transmitted to humans by the bite of the sandfly vector, are responsible for the three major forms of leishmaniasis, cutaneous, diffuse mucocutaneous and visceral. Leishmania spp.

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Nanoparticles composed of poly(isobutylcyanoacrylate) core coated with a mixture of chitosan and thiolated chitosan have already shown promising results in terms of mucoadhesion and permeation enhancement properties of pharmaceutical active drugs delivered via mucosal routes. In the present work, the cytotoxicity of these nanoparticles was first investigated using direct contact assay on undifferentiated human cervix epithelial HeLa cells. The results showed strong toxicity in HeLa cells for the two investigated concentrations 25 and 50 μg/mL.

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To be efficient, vaginal microbicide hydrogels should form a barrier against viral infections and prevent virus spreading through mucus. Multiple particle tracking was used to quantify the mobility of 170-nm fluorescently labeled COOH-modified polystyrene particles (COOH-PS) into thermosensitive hydrogels composed of amphiphilic triblock copolymers with block compositions EOn-POm-EOn (where EO refers to ethylene oxide and PO to propylene oxide) containing mucoadhesive hydroxypropylmethylcellulose (HPMC). COOH-PS were used to mimic the size and the surface charge of HIV-1.

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Both the endogenous antisecretory factor (AF) protein and peptide AF-16, which has a sequence that matches that of the active N-terminal region of AF, inhibit the increase in the epithelial transport of fluid and electrolytes induced by bacterial toxins in animal and ex vivo models. We conducted a study to investigate the inhibitory effect of peptide AF-16 against the increase of transcellular passage and paracellular permeability promoted by the secreted autotransporter toxin (Sat) in a cultured cellular model of the human intestinal epithelial barrier. Peptide AF-16 produced a concentration-dependent inhibition of the Sat-induced increase in the formation of fluid domes, in the mucosal-to-serosal passage of D-[1-(14)C]mannitol, and in the rearrangements in the distribution and protein expression of the tight junction (TJ)-associated proteins ZO-1 and occludin in cultured human enterocyte-like Caco-2/TC7 cell monolayers.

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A vast and diverse array of microbial species displaying great phylogenic, genomic, and metabolic diversity have colonized the gastrointestinal tract. Resident microbes play a beneficial role by regulating the intestinal immune system, stimulating the maturation of host tissues, and playing a variety of roles in nutrition and in host resistance to gastric and enteric bacterial pathogens. The mechanisms by which the resident microbial species combat gastrointestinal pathogens are complex and include competitive metabolic interactions and the production of antimicrobial molecules.

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Hosts are protected from attack by potentially harmful enteric microorganisms, viruses, and parasites by the polarized fully differentiated epithelial cells that make up the epithelium, providing a physical and functional barrier. Enterovirulent bacteria interact with the epithelial polarized cells lining the intestinal barrier, and some invade the cells. A better understanding of the cross talk between enterovirulent bacteria and the polarized intestinal cells has resulted in the identification of essential enterovirulent bacterial structures and virulence gene products playing pivotal roles in pathogenesis.

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We conducted experiments in order to examine whether the probiotic Lactobacillus casei strain Shirota YIT9029 (LcS) in vitro and in vivo antagonism of Helicobacter pylori and Salmonella, involves inhibition of the swimming motility of these pathogens. We report the irreversible inhibition of the swimming motility of H. pylori strain 1101 and reversible inhibition of Salmonella enterica serovar Typhimurium (S.

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Article Synopsis
  • Netosis is a process in which neutrophils release special traps called NETs to fight germs and can also be involved in other health issues.
  • Scientists created a new way to make and study these NETs from human blood cells, making sure they are high quality.
  • They found differences in the proteins and DNA levels in NETs from different people, but the method they developed works consistently, which is important for future research.
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The aim of the present work is to design a new formulation containing clotrimazole (CTZ) loaded into nanostructured lipid carriers (NLC) for the treatment of fungal vaginal infections. In order to obtain formulations with suitable viscosity for mucosal application, NLC containing CTZ produced by the ultrasonication method were viscosized by the addition of poloxamer P407 in the NLC dispersion (CTZ-NLC-gel). These systems exhibit well-known thermogelling properties.

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The miniCD4 M48U1 was formulated into thermosensitive and mucoadhesive pluronic(®) hydrogels as anti-HIV-1 microbicide. The release kinetics of M48U1 from F127/HPMC (20/1 wt%) and F127/F68/HPMC (22.5/2.

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Some water-borne protozoan parasites induce diseases through their membrane-associated functional structures and virulence factors that hijack the host cellular molecules and signalling pathways leading to structural and functional lesions in the intestinal barrier. In this Microreview we analyse the insights on the mechanisms of pathogenesis of Entamoeba intestinalis, Giardia and Cryptosporidium observed in the human colon carcinoma fully differentiated colon cancer cell lines, cell subpopulations and clones expressing the structural and functional characteristics of highly specialized fully differentiated epithelial cells lining the intestinal epithelium and mimicking structurally and functionally an intestinal barrier.

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We recently documented the neutrophil response to enterovirulent diffusely adherent Escherichia coli expressing Afa/Dr fimbriae (Afa/Dr DAEC), using the human myeloid cell line PLB-985 differentiated into fully mature neutrophils. Upon activation, particularly during infections, neutrophils release neutrophil extracellular traps (NETs), composed of a nuclear DNA backbone associated with antimicrobial peptides, histones, and proteases, which entrap and kill pathogens. Here, using fluorescence microscopy and field emission scanning electron microscopy, we observed NET production by PLB-985 cells infected with the Afa/Dr wild-type (WT) E.

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We report that both culture and the cell-free culture supernatant (CFCS) of Lactobacillus acidophilus strain LB (Lactéol Boucard) have the ability (i) to delay the appearance of Salmonella enterica serovar Typhimurium strain SL1344-induced mobilization of F-actin and, subsequently, (ii) to retard cell entry by S. Typhimurium SL1344. Time-lapse imaging and Western immunoblotting showed that S.

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Gardia intestinalis, the aetiological agent of giardiasis, one of the most common intestinal diseases in both developing and developed countries, induces a loss of epithelial barrier function and functional injuries of the enterocyte by mechanisms that remain unknown. Three possible mechanisms have been proposed: (i) Giardia may directly alter the epithelial barrier after a close interaction between the trophozoite and polarized intestinal cells, (ii) intestinal functions may be altered by factors secreted by Giardia including an 'enterotoxin', proteinases and lectins, and (iii) based on mouse studies, a mechanism involving the intervention of activated T lymphocytes. We used fully differentiated cultured human intestinal Caco-2/TC7 cells forming a monolayer and expressing several polarized functions of enterocytes of small intestine to investigate the mechanisms by which G.

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The secreted autotransporter toxin, Sat, which belongs to the subfamily of serine protease autotransporters of Enterobacteriaceae, acts as a virulence factor in extraintestinal and intestinal pathogenic strains of Escherichia coli. We observed that HeLa cells exposed to the cell-free culture supernatant of recombinant strain AAEC185p(Sat-IH11128) producing the Sat toxin (CFCS(Sat) ), displayed dramatic disorganization of the F-actin cytoskeleton before loosening cell-to-cell junctions and detachment. Examination of the effect of Sat on GFP-microtubule-associated protein light chain 3 (LC3) HeLa cells revealed that CFCS(Sat) -induced autophagy follows CFCS(Sat) -induced F-actin cytoskeleton rearrangement.

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CEACAM1 expressed by granulocytes and epithelial cells is recognized as a membrane-associated receptor by some Gram-negative pathogens. Here we report a previously unsuspected role of human CEACAM1-4L (hCEACAM1-4L) in polarized epithelial cells. We find that in contrast with non-transfected cells, Madin Darby Canine Kidney strain II (MDCK) engineered for the apical expression of the long cytoplasmic chain protein hCEACAM1-4L showed a serum-independent increase in the phosphorylation of the extracellular signal-regulated kinase 1/2 (Erk1/2) and p38 mitogen-activated protein kinases (MAPKs) after treatment with lipopolysaccharide (LPS) of wild-type, diffusely adhering Afa/Dr Escherichia coli (Afa/Dr DAEC) strain IH11128.

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