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Nutrient availability is a key determinant of tumor cell behavior. While nutrient-rich conditions favor proliferation and tumor growth, scarcity, and particularly glutamine starvation, promotes cell dedifferentiation and chemoresistance. Here, linking ribosome biogenesis plasticity with tumor cell fate, we uncover that the amino acid sensor GCN2 represses the expression of the precursor of ribosomal RNA, 47S, under metabolic stress. We show that blockade of GCN2 triggers cell death by an irremediable nucleolar stress and subsequent TP53-mediated apoptosis in patient-derived models of colon adenocarcinoma (COAD). In nutrient-rich conditions, GCN2 activity supports cell proliferation through the transcription stimulation of 47S rRNA, independently of the canonical ISR axis. However, impairment of GCN2 activity prevents nuclear translocation of the methionyl tRNA synthetase (MetRS) underlying the generation of a nucleolar stress, mTORC1 inhibition and autophagy induction. Inhibition of the GCN2-MetRS axis drastically improves the cytotoxicity of RNA pol I inhibitors, including the first-line chemotherapy oxaliplatin, on patient-derived COAD tumoroids. Our data thus reveal that GCN2 differentially controls the ribosome biogenesis according the nutritional context. Furthermore, pharmacological co-inhibition of the two GCN2 branches and the RNA pol I activity may represent a valuable strategy for elimination of proliferative and metabolically-stressed COAD cell.

Although the involvement of protein kinase CK2 in cancer is well-documented, there is a need for selective CK2 inhibitors suitable for investigating CK2 specific roles in cancer-related biological pathways and further explore its therapeutic potential. Here we have discovered AB668, a new bivalent inhibitor that binds both at the ATP site and an allosteric αD pocket unique to CK2. The molecule inhibits CK2 activity with an outstanding selectivity over other kinases. Using caspase activation assay, live-cell imaging and transcriptomic analysis, we have compared the effects of this bivalent inhibitor to the non-selective ATP-competitive inhibitor CX-4945 that reached clinic and to the selective ATP-competitive SGC-CK2-1 molecule. Our results show that in contrast to CX-4945 or SGC-CK2-1, AB668 has a distinct mechanism of action regarding its anti-cancer activity, inducing apoptotic cell death and stimulating distinct biological pathways in several cancer cell lines while sparing healthy cells. Our data suggest that targeting a cryptic CK2 αD pocket validates an allosteric approach to targeting CK2 and provides a starting point for creating drug-like CK2 inhibitors for aggressive cancers.

Rana El Sabeh,1,2 Mélanie Bonnet,1 Katy Le Corf,1 Kevin Lang,1 Alain Kfoury,1 Bassam Badran,2 Nader Hussein,2 Francois Virard,1 Isabelle Treilleux,3 Muriel Le Romancer,1 Serge Lebecque,1 Serge Manie,1 Isabelle Coste,1,* Toufic Renno1,* 1Université de Lyon, Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Centre de Recherche en Cancérologie de Lyon, Lyon, France; 2Université Libanaise, PRASE, Hadath, Lebanon; 3Pathology Department, Centre Léon Bérard, Lyon, France*These authors contributed equally to this workCorrespondence: Toufic Renno; Isabelle CosteCentre de Recherche en Cancétologie de Lyon, 28 Rue Laennec, Lyon, 69373, FranceTel +33 4 691 666 29; +33 4 691 666 30Email toufic.renno@lyon.unicancer.fr ; isabelle.coste@lyon.unicancer.frIntroduction: Most Toll-like receptors and IL-1/IL-18 receptors activate a signaling cascade via the adaptor molecule MyD88, resulting in NF-κB activation and inflammatory cytokine and chemokine production. Females are less susceptible than males to inflammatory conditions, presumably due to protection by estrogen. The exact mechanism underlying this protection is unknown.Methods: MCF7 cells expressing wild-type or mutated LXXLL motif were used to determine MyD88/estrogen receptor (ER)-a interaction by immunoprecipitation and cell activation by ELISA and luciferase reporter assay. IL-1b and/or E2 were used to activate MCF7 cells expressing normal or knocked down levels of PRMT1. Finally, in situ proximity ligation assay with anti-MyD88 and anti-methylated ER-a (methER-a) antibodies was used to evaluate MyD88/methylated ER-a interaction in THP1 cells and histological sections.Results: We show that MyD88 interacts with a methylated, cytoplasmic form of estrogen receptor-alpha (methER-α). This interaction is required for NF-κB transcriptional activity and pro-inflammatory cytokine production, and is dissociated by estrogen. Importantly, we show a strong gender segregation in gametogenic reproductive organs, with MyD88/methER-α interactions found in testicular tissues and in ovarian tissues from menopausal women, but not in ovaries from women age 49 and less – suggesting a role for estrogen in disrupting this complex in situ.Discussion: Collectively, our results indicate that the formation of MyD88/methER-α complexes during inflammatory signaling and their disruption by estrogen may represent a mechanism that contributes to gender bias in inflammatory responses.Keywords: nuclear receptor, post-translational modification, inflammation, protein-protein-interaction

This study explored the design of supersaturable self-microemulsifying drug delivery systems (S-SMEDDS) to address poor solubility and oral bioavailability of a novel benzimidazole derivative anticancer drug (BI). Firstly, self-microemulsifying drug delivery systems SMEDDS made of Miglyol (R) 812, Kolliphor (R) RH40, Transcutol (R) HP, and ethanol were prepared and loaded with the BI drug. Upon dispersion, the systems formed neutrally charged droplets of around 20 nm. However, drug precipitation was observed following incubation with simulated gastric fluid (pH 1.2). Aiming at reducing this precipitation and enhancing drug payload, supersaturable systems were then prepared by adding 1% hydroxypropyl cellulose as precipitation inhibitor. Supersaturable systems maintained a higher amount of drug in a supersaturated state in gastric medium compared with conventional formulations and were stable in simulated intestinal medium ( pH 6.8). In vitro cell studies using Caco-2 cell line showed that these formulations reduced in a transient manner the transepithelial electrical resistance of the monolayers without toxicity. Accordingly, confocal images revealed that the systems accumulated at tight junctions after a 2 h exposure. In vivo pharmacokinetic studies carried out following oral administration of BI-loaded S-SMEDDS, SMEDDS, and free drug to healthy mice showed that supersaturable systems promoted drug absorption compared with the other formulations. Overall, these data highlight the potential of using the supersaturable approach as an alternative to conventional SMEDDS for improving oral systemic absorption of lipophilic drugs. National Research Agency (ANR), HyDNano projectFrench National Research Agency (ANR) [ANR-18-CE18-0025-01]; ANRFrench National Research Agency (ANR) [42306YB]; Fundacao para a Ciencia e Tecnologia (FCT)Portuguese Foundation for Science and TechnologyEuropean Commission [42306YB]; FCTPortuguese Foundation for Science and TechnologyEuropean Commission [UID/Multi/04326/2019] info:eu-repo/semantics/publishedVersion

Background & Aims Low levels of toll-like receptor 3 (TLR3) in patients with hepatocellular carcinoma (HCC) are associated with poor prognosis, primarily owing to the loss of inflammatory signaling and subsequent lack of immune cell recruitment to the liver. Herein, we explore the role of TLR3-triggered apoptosis in HCC cells. Methods Quantitative reverse transcription PCR, western blotting, immunohistochemistry and comparative genomic hybridization were used to analyze human and mouse HCC cell lines, as well as surgically resected primary human HCCs, and to study the impact of TLR3 expression on patient outcomes. Functional analyses were performed in HCC cells, following the restoration of TLR3 by lentiviral transduction. The role of TLR3-triggered apoptosis in HCC was analyzed in vivo in a transgenic mouse model of HCC. Results Lower expression of TLR3 in tumor compared to non-tumor matched tissue was observed at both mRNA and protein levels in primary HCC, and was predictive of shorter recurrence-free survival after surgical resection in both univariate (hazard ratio [HR] 1.79; 95% CI 1.04–3.06; p = 0.03) and multivariate analyses (HR 1.73; CI 1.01–2.97; p = 0.04). Immunohistochemistry confirmed frequent downregulation of TLR3 in human and mouse primary HCC cells. None of the 6 human HCC cell lines analyzed expressed TLR3, and ectopic expression of TLR3 following lentiviral transduction not only restored the inflammatory response but also sensitized cells to TLR3-triggered apoptosis. Lastly, in the transgenic mouse model of HCC, absence of TLR3 expression was accompanied by a lower rate of preneoplastic hepatocyte apoptosis and accelerated hepatocarcinogenesis without altering the tumor immune infiltrate. Conclusion Downregulation of TLR3 protects transforming hepatocytes from direct TLR3-triggered apoptosis, thereby contributing to hepatocarcinogenesis and poor patient outcome. Lay summary Hepatocellular carcinoma (HCC) is a heterogeneous disease associated with a poor prognosis. In patients with HCC, TLR3 downregulation is associated with reduced survival. Herein, we show that the absence of TLR3 is associated with a lower rate of apoptosis, and subsequently more rapid hepatocarcinogenesis, without any change to the immune infiltrate in the liver. Therefore, the poor prognosis associated with low TLR3 expression in HCC is likely linked to tumors ability to escape apoptosis. TLR3 may become a promising therapeutic target in TLR3-positive HCC.

International audience

Veterinary-physicians collaboration towards the diminution of toxoplasmosis in France Toxoplasmosis is a globally distributed zoonosis caused by a protozoan Toxoplasma gondii able to infect all warm-blooded animals. Infection is generally asymptomatic or benign in humans except in cases of immunosuppression or maternal-fetal transmission (the cause of congenital toxoplasmosis). In livestock, it can be a source of abortions causing economic losses. Contamination is most often caused by ingestion of cysts (found in meat) or oocysts that contaminate plants or water. Only the part related to meat contamination is mentioned in this article. Thanks to a cooperation between veterinarians and physicians from the National Reference Laboratory of food-borne parasites (ANSES, Maisons-Alfort) and the National Reference Center for Toxoplasmosis, Reims (France), surveillance plans have been conducted aiming to estimate the levels of contamination of meat to better understand human epidemiology., La toxoplasmose est une zoonose de répartition mondiale, due au protozoaire Toxoplasma gondii capable d’infecter tous les animaux à sang chaud. L’infection est généralement inapparente ou bénigne chez l’homme sauf en cas d’immunodépression ou lors de transmission materno-fœtale (à l’origine de la toxoplasmose congénitale). Chez les animaux de rente, elle peut être source d’avortements à l’origine de pertes économiques. La contamination se fait le plus souvent par ingestion de kystes (présents dans les viandes) ou d’oocystes souillant les végétaux ou l’eau. Seule la part liée à la contamination des viandes est évoquée dans cet article. Grâce à une coopération entre vétérinaires et médecins du Laboratoire National de Référence Parasites transmis par les aliments (Anses, Maisons-Alfort) et du Centre National de Référence de la Toxoplasmose, Reims (France), des plans de surveillance ont été menés visant à estimer le niveau de contamination des viandes pour mieux comprendre l’épidémiologie humaine., Coste-Villena Isabelle, Blaga Radu. Coopération médico-vétérinaire et réduction de l’incidence de la toxoplasmose en France. In: Bulletin de l'Académie Vétérinaire de France tome 171 n°2, 2018. pp. 87-91.

Inflammation is emerging as a new hallmark of cancer, and the toll-like receptor and interleukin-1 receptor adaptor molecule MyD88 has been linked to tumorigenesis. The purpose of this review is to give a brief overview of the latest advances in understanding the complexity of MyD88 implication in tumorigenesis.MyD88 is shown to play a protumorigenic role through two mechanisms. First, it activates the nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway in the hematopoietic compartment and in tumor cells, inducing an inflammatory environment favorable to carcinogenesis. Second, it plays a cell-autonomous role in Ras signaling and transformation, independently of its role in inflammatory signaling. MyD88 mediates the optimal activation of the Ras/extracellular signal-regulated kinase (ERK) pathway by binding to ERK and protecting it from dephosphorylation. This optimal activation of the Ras pathway is essential for the expression of important DNA repair enzymes, allowing cancer cells to efficiently repair damaged DNA. MyD88 is also shown in certain cases to play an antitumoral role through modulation of the immune responseThese findings present a new dual function model for MyD88 implication in carcinogenesis making it a potential therapeutic target in cancer.

To ensure recognition of a broad variety of pathogens, the innate immune system has evolved, through a number of receptors, a strategy to recognize a limited number of conserved pathogen-associated molecular patterns. These receptors include the Toll-like receptors (TLRs), which are transmembrane receptors expressed in a variety of immune, but also epithelial and transformed cells (1). TLRs are connected to the cell signaling machinery via intracellular adaptor molecules. The first such adaptor molecule to be discovered was MyD88, which has an N-terminal death domain (DD), which recruits downstream signaling molecules (2). MyD88 is also an adaptor of the interleukin 1 receptor (IL-1R) family signaling. Activation of the TLR/IL-1R signaling pathway activates the major inflammatory transcription factor NF-kB by allowing its nuclear translocation. Inflammation is recognized as a promoter of carcinogenesis (3). Predictably, MyD88 was shown to play a role in tumorigenesis via TLR and IL-1 proinflammatory mechanisms (4). We have recently shown that MyD88 operates as an adaptor connecting inflammatory signaling pathways with the Ras oncogenic signaling pathway. Specifically, we showed that MyD88 is required for Ras-dependent cell signaling and transformation (5). Here we show in a panel of Ras-dependent colon cancer cell lines that, in addition to its role in tumor initiation, MyD88 plays an important role in the survival of Ras-transformed cells. We demonstrate that MyD88 is required for the expression of the major DNA repair enzyme ERCC1, and therefore for efficient DNA repair, and that knocking down MyD88 sensitizes colon cancer cells to genotoxic agents such as platinum salts in vitro and in vivo. These results indicate a novel and original link between inflammation, DNA repair, and cancer.

Objective. This study was performed to evaluate the efficacy and safety of a prebiotic treatment in the balance recovery of the vaginal flora in subjects previously treated for bacterial vaginosis (BV).Study Design. A randomized trial was carried out on 42 subjects with an active prebiotic group compared to a placebo group. The main evaluation criterion was the quantification of the vaginal flora measured by the Nugent score. Secondary criteria included vaginal pH and BV recurrence.Results. After 8 days of treatment, all subjects who received the prebiotic had a normal Nugent score, whereas 33% of the subjects treated with placebo had an intermediate or positive Nugent score. After 16 days of application, a normal Nugent score was maintained in all subjects treated with the prebiotic, whereas in the placebo group 24% of the subjects still had an elevated Nugent score. Moreover, the maintenance of (or reversion to) a normal flora was associated with the maintenance of (or reversion to) physiological pH values.Conclusions. The intravaginal gel treatment improves the recovery of a normal vaginal flora after the treatment of a BV episode, which should warrant a reduction in the risk of further recurrences.

Background & Aims: Inappropriate activation of β-catenin in adult tissues is associated with a wide variety of cancers, especially in the digestive tract. Classic transgenic and knockout murine models in which β-catenin is activated in large fields of cells have provided experimental support in favor of a role for this molecule in tumorigenesis. However, these models do not reproduce the sporadic nature of the majority of human cancers, beginning with the activation of an oncogene at random in a single cell. Methods: We used the "hit and run" strategy to generate a mouse model in which the expression of an activated form of β-catenin occurs sporadically in vivo. Results: Sporadic, multifocal lesions were observed in the stomach of 3% of mice aged 8 months and older. These lesions were associated with loss of Sonic hedgehog (Shh), and a causal relationship between β-catenin activation and Shh inhibition was established in gastric cells in vitro. No lesion was detected in the intestine or in the liver. In addition, one third of female mutant mice developed benign perimammary papillomas. Mutant mice were also hypersensitive to chemically induced premalignant skin lesions. Conclusions: These results challenge the view that activation of β-catenin induces malignant cancerogenesis, because they show in mice that sporadically activated β-catenin is sufficient for tumor initiation, yet without further malignant progression, and that it sensitizes cells to environmental hits. This model represents a powerful tool to investigate the interplay between genetic and environmental factors in tumor progression.

TLRs function as molecular sensors to detect pathogen-derived products and trigger protective responses ranging from secretion of cytokines that increase the resistance of infected cells and chemokines that recruit immune cells to cell death that limits microbe spreading. Viral dsRNA participate in virus-infected cell apoptosis, but the signaling pathway involved remains unclear. In this study we show that synthetic dsRNA induces apoptosis of human breast cancer cells in a TLR3-dependent manner, which involves the molecular adaptor Toll/IL-1R domain-containing adapter inducing IFN-β and type I IFN autocrine signaling, but occurs independently of the dsRNA-activated kinase. Moreover, detailed molecular analysis of dsRNA-induced cell death established the proapoptotic role of IL-1R-associated kinase-4 and NF-κB downstream of TLR3 as well as the activation of the extrinsic caspases. The direct proapoptotic activity of endogenous human TLR3 expressed by cancerous cells reveals a novel aspect of the multiple-faced TLR biology, which may open new clinical prospects for using TLR3 agonists as cytotoxic agents in selected cancers.

Cherubism is a rare autoinflammatory bone disorder that is associated with point mutations in the SH3-domain binding protein 2 (SH3BP2) gene, which encodes the adapter protein 3BP2. Individuals with cherubism present with symmetrical fibro-osseous lesions of the jaw, which are attributed to exacerbated osteoclast activation and defective osteoblast differentiation. Although it is a dominant trait in humans, cherubism appears to be recessively transmitted in mice, suggesting the existence of additional factors in the pathogenesis of cherubism. Here, we report that macrophages from 3BP2-deficient mice exhibited dramatically reduced inflammatory responses to microbial challenge and reduced phagocytosis. 3BP2 was necessary for LPS-induced activation of signaling pathways involved in macrophage function, including SRC, VAV1, p38MAPK, IKKα/β, RAC, and actin polymerization pathways. Conversely, we demonstrated that the presence of a single Sh3bp2 cherubic allele and pathogen-associated molecular pattern (PAMP) stimulation had a strong cooperative effect on macrophage activation and inflammatory responses in mice. Together, the results from our study in murine genetic models support the notion that infection may represent a driver event in the etiology of cherubism in humans and suggest limiting inflammation in affected individuals may reduce manifestation of cherubic lesions.

Accumulating evidence points to inflammation as a promoter of carcinogenesis. MyD88 is an adaptor molecule in TLR and IL-1R signaling that was recently implicated in tumorigenesis through proinflammatory mechanisms. Here we have shown that MyD88 is also required in a cell-autonomous fashion for RAS-mediated carcinogenesis in mice in vivo and for MAPK activation and transformation in vitro. Mechanistically, MyD88 bound to the key MAPK, Erk, and prevented its inactivation by its phosphatase, MKP3, thereby amplifying the activation of the canonical RAS pathway. The relevance of this mechanism to human neoplasia was suggested by the finding that MyD88 was overexpressed and interacted with activated Erk in primary human cancer tissues. Collectively, these results show that in addition to its role in inflammation, MyD88 plays what we believe to be a crucial direct role in RAS signaling, cell-cycle control, and cell transformation.

International audience; Multiple endocrine neoplasia. type 1 (MEN1) is a hereditary syndrome caused by the inactivation of the responsible gene, MEN1. To date, the lack of MEN1-deficient cell lines derived directly from MEN1 tumours has hampered the detailed study of the MEN1 gene. We have established several stable Men1-deficient Leydig cell tumour (LCT) lines derived from a Leydig cell tumour developed in a male heterozygous Men I mutant mouse. Our data show that these cell lines maintain the basic characteristics of Leydig cells in terms of both androgen synthesis and gene expression. interestingly, reconstituted menin expression in one of Men1-deficient LCT cell lines resulted in cell growth inhibition, suggesting that the function of cell growth suppression of the menin pathway, apart from menin itself, is essentially preserved in these cells. Furthermore, we show that menin re-expression in these Men1-deficient cells leads to a block in the transition from G0/G1 to S phase of the cell cycle and an increase in apoptosis, accompanied by a marked increase of p18(INK4C) and p27(Kip1) expression. The current study therefore highlights the importance of menin expression in cell cycle and cell survival control in endocrine cells, and may provide insights into the mechanisms of tumour suppression by menin in related endocrine tumours.

Langerin is a C-type lectin expressed by a subset of dendritic leukocytes, the Langerhans cells (LC). Langerin is a cell surface receptor that induces the formation of an LC-specific organelle, the Birbeck granule (BG). We generated a langerin(-/-) mouse on a C57BL/6 background which did not display any macroscopic aberrant development. In the absence of langerin, LC were detected in normal numbers in the epidermis but the cells lacked BG. LC of langerin(-/-) mice did not present other phenotypic alterations compared to wild-type littermates. Functionally, the langerin(-/-) LC were able to capture antigen, to migrate towards skin draining lymph nodes, and to undergo phenotypic maturation. In addition, langerin(-/-) mice were not impaired in their capacity to process native OVA protein for I-A(b)-restricted presentation to CD4(+) T lymphocytes or for H-2K(b)-restricted cross-presentation to CD8(+) T lymphocytes. langerin(-/-) mice inoculated with mannosylated or skin-tropic microorganisms did not display an altered pathogen susceptibility. Finally, chemical mutagenesis resulted in a similar rate of skin tumor development in langerin(-/-) and wild-type mice. Overall, our data indicate that langerin and BG are dispensable for a number of LC functions. The langerin(-/-) C57BL/6 mouse should be a valuable model for further functional exploration of langerin and the role of BG.

We have previously identified a mAb that binds to a molecule expressed preferentially on the surface of cycling thymocytes. In this study the molecule recognized by this mAb has been identified in the mouse as CD147 (basigin) by expression cloning. We show that CD147 expression correlates with cycling of immature thymocytes even in the absence of TCRβ selection and that ligation of this molecule on immature fetal thymocytes inhibits their further development into mature T cells.

Adhesive interactions with stromal cells and the extracellular matrix are essential for the differentiation and migration of hematopoietic progenitors. In the erythrocytic lineage, a number of adhesion molecules are expressed in the developing erythrocytes and are thought to play a role in the homing and maturation of erythrocytic progenitors. However, many of these molecules are lost during the final developmental stages leading to mature erythrocytes. One of the adhesion molecules that remains expressed in mature, circulating erythrocytes is CD147. This study shows that blockade of this molecule on the cell surface by treatment with F(ab')(2) fragments of anti-CD147 monoclonal antibody disrupts the circulation of erythrocytes, leading to their selective trapping in the spleen. Consequently, mice develop an anemia, and de novo, erythropoietin-mediated erythropoiesis in the spleen. In contrast, these changes were not seen in mice similarly treated with another antierythrocyte monoclonal antibody with a different specificity. These results suggest that the CD147 expressed on erythrocytes likely plays a critical role in the recirculation of mature erythrocytes from the spleen into the general circulation. (Blood. 2001;97:3984-3988)

The recent identification of tumor Ags as potential vaccines has prompted the search for efficient adjuvants and delivery systems, especially in the case of peptide-based vaccination protocols. Here, we investigated the adjuvant potential of the recombinant 40-kDa outer membrane protein of Klebsellia pneumoniae (P40) for specific CTL induction. We studied the CTL response induced in HLA-A*0201/Kb transgenic mice immunized with peptides derived from two melanoma-associated differentiation Ags, the HLA-A*0201-restricted decapeptide Melan-A26–35 substituted at position 2 and the Kb-restricted tyrosinase-related protein 2181–188 T cell epitope. We found that both peptides are able to generate a specific CTL response when mixed with the protein in the absence of conventional adjuvant. This CTL response is a function of the amount of P40 used for immunization. Moreover, the CTL response generated against the tyrosinase-related protein 2181–188 peptide in presence of P40 is associated with tumor protection in two different experimental models and is independent of the presence of CD4+ T lymphocytes. Thus, the recombinant bacterial protein P40 functions as a potent immunological adjuvant for specific CTL induction.

BACKGROUND: This double-blind, randomized, crossover study compared the potential analgesic effect of the serotonin receptor antagonist UP 26-91 (50 mg, 150 mg and 300 mg) with that of codeine (100 mg) and placebo by use of different human experimental pain models.SUBJECTS AND METHODS: In experiment 1, pain detection and tolerance thresholds to heat, pressure and pain ratings during the cold pressor test were measured. In experiment 2, the pain threshold to single and repetitive (temporal summation) electrical sural nerve stimulation, and the pain intensity on a visual analogue scale to supra pain threshold electrical stimulation (stimulus-response-function) were measured. Tests were performed before, and 1, 2 and 6 h after drug administration.RESULTS: UP 26-91 did not show a marked effect on the experimental pain tests. Most of the variables tended to show a better effect from codeine than from placebo, but statistical significance for peak pain was only reached during the cold pressor test (P=0.011).CONCLUSIONS: In the present doses, the serotonin antagonist UP 26-91 had no effect on the experimental pain models applied.

Survival and adherence of C. parvum on vegetable food matrices are poorlyinvestigated. However, human contamination can occur through consumption of raw or undercookedfood. Food-borne outbreaks related to the consumption of green leafy foodcontaminated with C. parvum are regularly reported. Transmission of the parasite to humans isassociated with the parasite ability to adhere, persist and survive in food, but data are scarce.This project aimed to study the survival of oocysts onto lamb’s lettuce leaves, a potential sourceof contamination, under the growing conditions of vegetables and the food industry (washingprocess) and studied involved interactions in the parasite adherence on vegetable matrix.Results show that the parasite persists throughout the growth of lamb's lettuce but loses itsinfectivity after two weeks. Washing as performed in the food industry neither reduces theparasitic load nor impacts its infectivity. Moreover, the environment in which Cryptosporidiumis found when it comes into contact with the lamb’s lettuce mediates its adherence, which canbe done through certain carbohydrates and their receptors present on both or each surface of theparasite and/or the plant., La survie et l’adhérence de Cryptosporidium à la surface des matrices alimentairesvégétales sont peu documentées. Or, la contamination de l’Homme peut se faire, entre autres,par la consommation d’aliments contaminés consommés crus, peu cuits ou peu transformés.Des épidémies d’origine alimentaires liées à la consommation de végétaux à feuilles vertescontaminés par C. parvum sont ainsi régulièrement rapportées. La transmission du parasite àl’Homme est liée à la capacité du parasite à adhérer, persister et survivre sur les aliments. Aussi,les travaux présentés ici visent à étudier la survie des oocystes à la surface de la mâche, sourcepotentielle de contamination, dans les conditions de croissance du végétal et en industrieagroalimentaire (procédé de lavage). Les interactions mises en oeuvre permettant l’adhérencedu parasite sur ces matrices ont également été étudiées. Les résultats montrent que le parasitepersiste tout au long de la croissance de la mâche mais perd son infectiosité après deuxsemaines. Le lavage tel que réalisé en industrie agroalimentaire ne permet pas de réduiretotalement la charge parasitaire et n’a aucun impact sur son infectiosité. De plus, le milieu danslequel se trouve Cryptosporidium lorsqu’il entre en contact avec la mâche médie son adhérence,qui peut se faire par l’intermédiaire de certains sucres et de leurs récepteurs présents à la surfacedu parasite et/ou du végétal.