Mécanismes moléculaires de l'inhibition de la réponse immune innée par Mycobacterium tuberculosis

La détection de Mycobacterium tuberculosis (M. tb) par le système immunitaire inné fait intervenir différents récepteurs appelés "Pattern Recognition Receptor " (PRR), parmi lesquels on trouve des récepteurs "Toll-like" (TLR1, 2, 4, 8 et 9), NOD2, ainsi que des lectines de type C, telles que le Récepteur au Mannose (RM) et DC-SIGN. L'action concertée de ces récepteurs se traduit d'une part, par la phagocytose des mycobactéries, et d'autre part, par l'activation de voies de signalisation intracellulaires, aboutissant à la translocation de facteurs de transcription nucléaires (notamment NF-kB et AP-1) et à l'expression et la régulation de gènes codant pour des cytokines et des chimiokines. Cependant, M. tb est capable d'inhiber la réponse immune innée, notamment la réponse inflammatoire, favorisant ainsi sa survie dans les macrophages infectés. Dans ce contexte, mes travaux ont consisté à explorer les mécanismes moléculaires utilisés par le bacille pour inhiber la réponse immune innée, en me focalisant plus particulièrement sur les composés immunomodulateurs de nature (glyco)lipidique de l'enveloppe. La stratégie a consisté à cribler une banque d'environ 11 000 mutants de transposition de M. tb sur la lignée macrophagique humaine THP-1 exprimant un système rapporteur de l'activation de NF-kB. Cette lignée exprime la plupart des PRRs impliqués dans la détection de M. tb: TLR2, 4, 9, Récepteur au Mannose, DC-SIGN, Mincle, NOD2. A l'issue de ce criblage et des étapes de validation, un mutant, dont le gène mmpL8 est interrompu, a été sélectionné pour une étude approfondie car : i) il induit une activation de NF-kB supérieure à la souche sauvage et est donc susceptible d'être affecté dans un mécanisme d'inhibition utilisé par M. tb, et ii) il est altéré pour la biosynthèse de glycolipides spécifiques de M. tb, les sulfolipides, composés suspectés d'être impliqués dans la virulence du bacille. Nous nous sommes attachés à déterminer par quels mécanismes moléculaires et cellulaires les sulfolipides sont capables d'exercer cette inhibition. Une étude des relations structures/fonctions des sulfolipides pour leurs propriétés inhibitrices et l'utilisation de différents modèles cellulaires, nous ont permis de montrer que les sulfolipides agissent comme antagonistes de TLR2, inhibant ainsi les voies de signalisation associées à ce récepteur. Nous avons ainsi pu mettre en évidence un nouveau mécanisme d'inhibition de la réponse cellulaire par M. tb impliquant les sulfolipides mycobactériens et le récepteur TLR2Mycobacterium tuberculosis (M. tb) detection by innate immune system involves different receptors called, Pattern Recognition Receptors (PRRs), which include: Toll-like receptors (TLR1, 2, 4, 8 and 9), NOD2, and C-type lectins such as the mannose receptor (MR) or DC-SIGN. The concerted action of these receptors results in the phagocytosis of mycobacteria and activation of intracellular signaling pathways, leading to nuclear translocation of transcription factors (such as NF-kB and AP -1) inducing genes expression and regulation of cytokines and chemokines. However, M. tb is also able to inhibit the innate immune response, most particularly the inflammatory response, thus promoting its survival in infected macrophages. In this context, my work was aimed at deciphering the mechanisms used by M. tb to inhibit the innate immune response, by focusing on immunomodulatory (glyco)lipids of the bacilli envelope. The strategy consisted in screening a library of about 11,000 transposition mutants of M. tb on a human THP-1 macrophage cell line expressing a reporter system for NF-kB activation. This cell line expresses most of the PRRs involved in the detection of M. tb: TLR2, 4, 9, mannose receptor, DC-SIGN, Mincle, NOD2. After the screening and validation steps, a mutant disrupted in the mmpL8 gene was selected for further study because: i) it induced an increased NF-kB activation as compared to the wild-type strain and was thus likely to be affected in an inhibition mechanism used by M. tb, and ii) it was altered for the biosynthesis of M. tb specific glycolipids, namely sulfolipids, which suspected to be involved in the bacilli virulence. We investigated by which molecular and cellular mechanisms sulfolipids were able to inhibit the innate immune response. By performing the structures/activities relationships study of sulfolipids inhibitory properties and using different cell models, we were able to show that sulfolipids act as TLR2 antagonists, thereby inhibiting the signaling pathways associated to this receptor. In conclusion, we highlighted a new inhibitory mechanism of innate immune response, involving M. tb mycobacterial sulfolipids and TLR

High-resolution mapping of fluoroquinolones in TB rabbit lesions reveals specific distribution in immune cell types.

Understanding the distribution patterns of antibiotics at the site of infection is paramount to selecting adequate drug regimens and developing new antibiotics. Tuberculosis (TB) lung lesions are made of various immune cell types, some of which harbor persistent forms of the pathogen, Mycobacterium tuberculosis. By combining high resolution MALDI MSI with histology staining and quantitative image analysis in rabbits with active TB, we have mapped the distribution of a fluoroquinolone at high resolution, and identified the immune-pathological factors driving its heterogeneous penetration within TB lesions, in relation to where bacteria reside. We find that macrophage content, distance from lesion border and extent of necrosis drive the uneven fluoroquinolone penetration. Preferential uptake in macrophages and foamy macrophages, where persistent bacilli reside, compared to other immune cells present in TB granulomas, was recapitulated in vitro using primary human cells. A nonlinear modeling approach was developed to help predict the observed drug behavior in TB lesions. This work constitutes a methodological advance for the co-localization of drugs and infectious agents at high spatial resolution in diseased tissues, which can be applied to other diseases with complex immunopathology

MALDI-MSI Towards Multimodal Imaging: Challenges and Perspectives

Multimodal imaging is a powerful strategy for combining information from multiple images. It involves several fields in the acquisition, processing and interpretation of images. As multimodal imaging is a vast subject area with various combinations of imaging techniques, it has been extensively reviewed. Here we focus on Matrix-assisted Laser Desorption Ionization Mass Spectrometry Imaging (MALDI-MSI) coupling other imaging modalities in multimodal approaches. While MALDI-MS images convey a substantial amount of chemical information, they are not readily informative about the morphological nature of the tissue. By providing a supplementary modality, MALDI-MS images can be more informative and better reflect the nature of the tissue. In this mini review, we emphasize the analytical and computational strategies to address multimodal MALDI-MSI.Imagerie multimodale combinant la spectroscopie Raman et la spectrométrie de masse appliquée à la tuberculos

Fluoroquinolone Efficacy against Tuberculosis Is Driven by Penetration into Lesions and Activity against Resident Bacterial Populations.

Fluoroquinolones represent the pillar of multidrug-resistant tuberculosis (MDR-TB) treatment, with moxifloxacin, levofloxacin, or gatifloxacin being prescribed to MDR-TB patients. Recently, several clinical trials of "universal" drug regimens, aiming to treat drug-susceptible and drug-resistant TB, have included a fluoroquinolone. In the absence of clinical data comparing their side-by-side efficacies in controlled MDR-TB trials, a pharmacological rationale is needed to guide the selection of the most efficacious fluoroquinolone. The present studies were designed to test the hypothesis that fluoroquinolone concentrations (pharmacokinetics) and activity (pharmacodynamics) at the site of infection are better predictors of efficacy than the plasma concentrations and potency measured in standard growth inhibition assays and are better suited to determinations of whether one of the fluoroquinolones outperforms the others in rabbits with active TB. We first measured the penetration of these fluoroquinolones in lung lesion compartments, and their potency against bacterial populations that reside in each compartment, to compute lesion-centric pharmacokinetic-pharmacodynamic (PK/PD) parameters. PK modeling methods were used to quantify drug penetration from plasma to tissues at human-equivalent doses. On the basis of these metrics, moxifloxacin emerged with a clear advantage, whereas plasma-based PK/PD favored levofloxacin (the ranges of the plasma AUC/MIC ratio [i.e., the area under the concentration-time curve over 24 h in the steady state divided by the MIC] are 46 to 86 for moxifloxacin and 74 to 258 for levofloxacin). A comparative efficacy trial in the rabbit model of active TB demonstrated the superiority of moxifloxacin in reducing bacterial burden at the lesion level and in sterilizing cellular and necrotic lesions. Collectively, these results show that PK/PD data obtained at the site of infection represent an adequate predictor of drug efficacy against TB and constitute the baseline required to explore synergies, antagonism, and drug-drug interactions in fluoroquinolone-containing regimens

Volume 98 Issue 5, pp. 899-1054

ECOLOGY-EPIDEMIOLOGY-BEHAVIOR Increased Surfacing Behavior in Longnose Killifish Infected by Brain-Encysting Trematode. B. L. FREDENSBORG and A. N. LONGORIA - 899 Spatial Structure of Helminth Communities in the Golden Grey Mullet, Liza aurata (Actinopterygii: Mugilidae), From the Western Mediterranean. RAUL MIGUEZ-LOZANO, TRINIDAD V. PARDO-CARRANZA, ISABEL BLASCO-COSTA, and JUAN ANTONIO BALBUENA - 904 Hepatozoon Infection Prevalence in Four Snake Genera: Influence of Diet, Prey Parasitemia Levels, or Parasite Type? BEATRIZ TOME, JOAD P. M. C. MAIA, and D. JAMES HARRIS - 913 ECTOPARASITOLOGY Molecular Identification and Description of the Female of Nothoaspis reddelli (Ixodida: Argasidae) From a Cave in Southeastern Mexico. CARMEN GUZMAN-CORNEJO, RICARDO PAREDES-LEON, MARCELO B. LABRUNA, SANTIAGO NAVA, and JOSE M. VENZAL - 918 Prevalence of Hemoproteus iwa in Galapagos Great Frigatebirds (Fregata minor) and Their Obligate Fly Ectoparasite (01- Jersia spiniJera). IRIS I. LEVIN and PATRICIA G. PARKER - 924 Variable Microsatellite Loci for Population Genetic Analysis of Old World Monkey Lice (Pedicinus sp.). KATLYN SCHOLL, JULIE M. ALLEN, FABIAN H. LEENDERTZ, COLIN A. CHAPMAN, and DAVID L. REED - 930 FUNCTIONAL MORPHOLOGY Ultrastructural Study of Vitellogenesis of Aphallus tubarium (Rudolphi, 1819) Poche, 1926 (Digenea: Cryptogonimidae), an Intestinal Parasite of Dentex dentex (Pisces: Teleostei). SAMUEL GREANI, YANN QUILICHINI, JOSEPHINE FOATA, and BERNARD MARCHAND - 938 IMMUNOLOGY Seroprevalence of Toxoplasma gondii Infection in Domestic Horses in Durango State, Mexico. C. ALVARADO-ESQUIVEL, S. RODRIGUEZ-PENA, I. VILLENA, and J. P. DUBEY - 944 INVERTEBRATE-PARASITE RELATIONSHIPS Excystation Signals Do Not Isolate Gregarine Gene Pools: Experimental Excystation of Blabericola migrator Among 11 Species of Cockroaches. SHELBY M. STEELE, DEBRA T. CLOPTON, and RICHARD E. CLOPTON - 946 LIFE CYCLES-SURVEY A New Sarcocystis Species (Apicomplexa: Sarcocystidae) From the Rock Gecko Bunopus tuberculatus in Saudi Arabi. A. S. ABDEL-BAKI, H. M. ABDEL-HALEEM, and S. AL-QURAISHY - 951 A Retrospective Study of Abattoir Condemnation Due to Parasitic Infections: Economic Importance in Ahwaz, Southwestern Iran. HASSAN BORJI, MOHAMMAD AZIZZADEH, and MEHRAB KAMELLI - 954 Prevalence of Eimeria Infection in Yaks on the Qinghai-Tibet Plateau of China. HUI DONG, CHUNHUA LI, QIPING ZHAO, JING LI, HONGYU HAN, LIANLIAN JIANG, SHUNHAI ZHU, TING LI, CHUNLIN KONG, BING HUANG, and JINZHONG CAI - 958 Prevalence of Coccidial Infection in Dairy Cattle in Shanghai, China. HUI DONG, QIPING ZHAO, HONGYU HAN, LIANLIAN JIANG, SHUNHAI ZHU, TING LI, CHUNLIN KONG, and BING HUANG - 963 Genetic Sequence Data Identifies the Cercaria of Drepanocephalus spathans (Digenea: Echinostomatidae), a Parasite of the Double-Crested Cormorant (Phalacrocorax auritus), with Notes on Its Pathology in Juvenile Channel Catfish (Ictalurus punctatus). MATT J. GRIFFIN, LESTER H. KHOO, SYLVIE M. QUINIOU, MARY M. O\u27HEAR, LINDA M. POTE, TERRENCE E. GREENWAY, and DAVID J. WISE - 967 SYSTEMATICS-PHYLOGENETICS A New Species of Megalobatrachonema (Nematoda: Kathlaniidae) in Fojia bumui (Squamata: Scincidae) From Papua New Guinea. CHARLES R. BURSEY, STEPHEN R. GOLDBERG, and FRED KRAUS - 973 Two New Species of Schizorchis (Cestoda: Anoplocephalidae) From Leporids (Lagomorpha: Leporidae) in China. KUIZHENG CAI, JIALIN BAI, and SHIEN CHEN - 977 The Genus Guerrerostrongylus (Nematoda: Heligmonellidae) in Cricetid Rodents From the Atlantic Rain Forest of Misiones, Argentina: Emended Description of Guerrerostrongylus zetta (Travassos, 1937) and Description of a New Species. MARIA CELINA DIGIANI, JULIANA NOTARNICOLA, and GRACIELA T. NAVONE - 985 A New Microphallid (Digenea) Species From Lontra provocax (Mammalia: Mustelidae) From Freshwater Environments of Northwestern Patagonia (Argentina). VERONICA R. FLORES, NORMA L. BRUGNI, and CARLA M. POZZI - 992 Description of Riouxgolvania kapapkamui sp. n. (Nematoda: Muspiceoidea: Muspiceidae), a Peculiar Intradermal Parasite of Bats in Hokkaido, Japan. HIDEO HASEGAWA, MASAHIKO SATO, KISHIO MAEDA, and YOSHIKO MURAYAMA - 995 A New Species of Choleoeimeria (Apicomplexa: Eimeriidae) From Meller\u27s Chameleon, Trioceros melleri (Sauria: Chamaeleonidae). CHRIS T. McALLISTER - 1001 A New Species of Eimeria (Apicomplexa: Eimeriidae) From the Northern Myotis, Myotis septentrionalis (Chiroptera: Vespertilionidae), in Oklahoma. CHRIS T. McALLISTER, R. SCOTT SEVILLE, and ZACHARY P. ROEHRS - 1003 A New Spirurid (Nematoda) Parasite From Mormoopid Bats in Mexico. JORGE LUIS PERALTA-RODRIGUEZ, JUAN MANUEL CASPETA-MANDUJANO, and JOSE ANTONIO GUERRERO - 1006 THERAPEUTICS-DIAGNOSTICS Resistance of Rhipicephalus microplus to Amitraz and Cypermethrin in Tropical Cattle Farms in Veracruz, Mexico. AGUSTIN FERNANDEZ-SALAS, ROGER IVAN RODRIGUEZ-VIVAS, and MIGUEL ANGEL ALONSO-DIAZ - 1010 RESEARCH NOTES Seroprevalence Study on Theileria equi and Babesia caballi Antibodies in Horses From Central Province of Saudi Arabia. A. D. ALANAZI, M. S. ALYOUSIF, and M. M. HASSIEB - 1015 Influence of Rangelia vitalii (Apicomplexa: Piroplasmorida) on Copper, Iron and Zinc Bloodstream Levels in Experimentally Infected Dogs, ALEKSANDRO S, DA SILVA, RAQUELI T. FRANC;:A, MARCIO M. COSTA, CARLOS B. V. PAIM, FRANCINE C. PAIM, CLARISSA M. M. SANTOS, ERICO M. M. FLORES, TIAGO L. EILERS, CINTHIA M. MAZZANTI, SILVIA G. MONTEIRO, CARLOS H. DO AMARAL, and SONIA T. A. LOPES - 1018 Plagiorchis elegans (Trematoda) Induces Immune Response in an Incompatible Snail Host Biomphalaria glabrata (Pulmonata: Planorbidae). S. P. DAOUST, M. E. RAU, and J. D. McLAUGHLIN - 1021 Prevalence and Intensity of Fish-Borne Zoonotic Trematodes in Cultured Freshwater Fish From Rural and Urban Areas of Northern Vietnam. NGUYEN VAN DE, THANH HOA LE, and K. D. MURRELL - 1023 Details of the Paranephridial System of a Species of Prohyptiasmus (Cyclocoelidae: Hyptiasminae) From an American Coot, Fulica americana (Rallidae) in Oklahoma. NORMAN O. DRONEN, F. AGUSTIN JIMENEZ, and SCOTT L. GARDNER - 1026 Surface Ultrastructure of the Eggs of Malacopsylla grossiventris and Phthiropsylla agenoris (Siphonaptera: Malacopsyllidae). M. C. EZQUIAGA and M. LARES CHI - 1029 Prevalence of Ancylostoma braziliense in Cats in Three Northern Counties of Florida, United States. JANICE L. LIOTTA, KHUANCHAI N. KOOMPAPONG, JOSEPH P. YAROS, JOSEPH PRULLAGE, and DWIGHT D. BOWMAN - 1032 Obtaining an Isolate of Ancylostoma braziliense From Dogs Without the Need for Necropsy. JANICE L. LIOTTA, ALICE C. Y. LEE, SARP AKSEL, IBRAHIM ALKHALIFE, ALEJANDRO CRUZ-REYES, HEEJEONG YOUN, STEPHEN E. BIENHOFF, and DWIGHT D. BOWMAN - 1034 Obtaining an Isolate of Ancylostoma braziliense From Cats Without the Need for Necropsy. JANICE L. LIOTTA, ALICE C. Y. LEE, KHUANCHAI N. KOOMPAPONG, JOSEPH P. YAROS, JOSEPH PRULLAGE, MICHAEL A. ULRICH, and DWIGHT D. BOWMAN - 1037 Prevalence of Ancylostoma braziliense in Dogs From Alachua and Marion Counties, Florida, United States. JANICE L. LIOTTA, HEEJEONG YOUN, SARP AKSEL, STEPHEN E. BIENHOFF, and DWIGHT D. BOWMAN - 1039 Morphological Differentiation of Eggs of Ancylostoma caninum, Ancylostoma tubaeforme, and Ancylostoma braziliense From Dogs and Cats in the United States. ARACELI LUCIO-FORSTER, JANICE L. LIOTTA, JOSEPH P. YAROS, KAITLYN R. BRIGGS, HUSSNI O. MOHAMMED, and DWIGHT D. BOWMAN - 1041 Molecular and Immunological Characterization of a Novel 32-kDa Secreted Protein of Babesia microti. HIDEO OOKA, MOHAMAD A. TERKAWI, SHINUO CAO, GABRIEL ABOGE, YO UN-KYOUNG GOO, YUZI LUO, YAN LI, YOSHIFUMI NISHIKAWA, IKUO IGARASHI, and XUENAN XUAN - 1045 DNA Barcoding of Schistosome Cercariae Reveals a Novel Sub-Lineage within Schistosoma rodhaini From Ngamba Island Chimpanzee Sanctuary, Lake Victoria. C. J. STANDLEY and J. R. STOTHARD - 1049 Host Susceptibility Is Altered by Light Intensity After Exposure to Parasites. MICHELLE L. STEINAUER and KAITLIN M. BONNER - 1052 ANNOUNCEMENT: Change in Editorship - 903 ERRATUM - 91

Identification of an inter-transcription factor regulatory network in human hepatoma cells by Matrix RNAi

Transcriptional regulation by transcriptional regulatory factors (TRFs) of their target TRF genes is central to the control of gene expression. To study a static multi-tiered inter-TRF regulatory network in the human hepatoma cells, we have applied a Matrix RNAi approach in which siRNA knockdown and quantitative RT-PCR are used in combination on the same set of TRFs to determine their interdependencies. This approach focusing on several liver-enriched TRF families, each of which consists of structurally homologous members, revealed many significant regulatory relationships. These include the cross-talks between hepatocyte nuclear factors (HNFs) and the other TRF groups such as CCAAT/enhancer-binding proteins (CEBPs), retinoic acid receptors (RARs), retinoid receptors (RXRs) and RAR-related orphan receptors (RORs), which play key regulatory functions in human hepatocytes and liver. In addition, various multi-component regulatory motifs, which make up the complex inter-TRF regulatory network, were identified. A large part of the regulatory edges identified by the Matrix RNAi approach could be confirmed by chromatin immunoprecipitation. The resultant significant edges enabled us to depict the inter-TRF TRN forming an apparent regulatory hierarchy of (FOXA1, RXRA) → TCF1 → (HNF4A, ONECUT1) → (RORC, CEBPA) as the main streamline

Transcriptional Rewiring, Adaptation, and the Role of Gene Duplication in the Metabolism of Ethanol of Saccharomyces cerevisiae

Ethanol is the main by-product of yeast sugar fermentation that affects microbial growth parameters, being considered a dual molecule, a nutrient and a stressor. Previous works demonstrated that the budding yeast arose after an ancient hybridization process resulted in a tier of duplicated genes within its genome, many of them with implications in this ethanol 'produce-accumulate-consume' strategy. The evolutionary link between ethanol production, consumption, and tolerance versus ploidy and stability of the hybrids is an ongoing debatable issue. The implication of ancestral duplicates in this metabolic rewiring, and how these duplicates differ transcriptionally, remains unsolved. Here, we study the transcriptomic adaptive signatures to ethanol as a nonfermentative carbon source to sustain clonal yeast growth by experimental evolution, emphasizing the role of duplicated genes in the adaptive process. As expected, ethanol was able to sustain growth but at a lower rate than glucose. Our results demonstrate that in asexual populations a complete transcriptomic rewiring was produced, strikingly by downregulation of duplicated genes, mainly whole-genome duplicates, whereas small-scale duplicates exhibited significant transcriptional divergence between copies. Overall, this study contributes to the understanding of evolution after gene duplication, linking transcriptional divergence with duplicates' fate in a multigene trait as ethanol tolerance

Measurement of the cross-section for Z → e⁺e^- production in pp collisions at &#8730;<span style="text-decoration:overline">s</span>=7 TeV

A measurement of the cross-section for pp → Z → e+e− is presented using data at s√=7 TeV corresponding to an integrated luminosity of 0.94 fb−1. The process is measured within the kinematic acceptance p T &#62; 20 GeV/c and 2 &#60; η &#60; 4.5 for the daughter electrons and dielectron invariant mass in the range 60–120 GeV/c 2. The cross-section is determined to be σ(pp→Z→e+e−)=76.0±0.8±2.0±2.6pb where the first uncertainty is statistical, the second is systematic and the third is the uncertainty in the luminosity. The measurement is performed as a function of Z rapidity and as a function of an angular variable which is closely related to the Z transverse momentum. The results are compared with previous LHCb measurements and with theoretical predictions from QCD