References of "Bureau, Fabrice"
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See detailLung resident eosinophils represent a distinct cell subset with homeostatic functions
Mesnil, Claire ULg; Raulier, Stéfanie ULg; Paulissen, Geneviève et al

Conference (2016, October 21)

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See detailCpG-DNA expand immunosuppressive interstitial macrophages from Ly6c+ local precursors
Sabatel, Catherine ULg; Radermecker, Coraline ULg; Fievez, Laurence ULg et al

in Proceeding of Cell Symposia: 100 years of phagocytes (2016, September)

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See detailAsthma inflammatory phenotypes show differential microRNA expression in sputum.
Maes, Tania; Cobos, Francisco Avila; SCHLEICH, FLorence ULg et al

in The Journal of allergy and clinical immunology (2016), 137(5), 1433-46

BACKGROUND: Asthma is classified according to severity and inflammatory phenotype and is likely to be distinguished by specific microRNA (miRNA) expression profiles. OBJECTIVE: We sought to associate ... [more ▼]

BACKGROUND: Asthma is classified according to severity and inflammatory phenotype and is likely to be distinguished by specific microRNA (miRNA) expression profiles. OBJECTIVE: We sought to associate miRNA expression in sputum supernatants with the inflammatory cell profile and disease severity in asthmatic patients. METHODS: We investigated miRNA expression in sputum supernatants of 10 healthy subjects, 17 patients with mild-to-moderate asthma, and 9 patients with severe asthma using high-throughput, stem-loop, reverse transcriptase quantitative real-time PCR miRNA expression profiling (screening cohort, n = 36). Differentially expressed miRNAs were validated in an independent cohort (n = 60; 10 healthy subjects and 50 asthmatic patients). Cellular miRNA origin was examined by using in situ hybridization and reverse transcriptase quantitative real-time PCR. The functional role of miRNAs was assessed by using in silico analysis and in vitro transfecting miRNA mimics in human bronchial epithelial cells. RESULTS: In 2 independent cohorts expression of miR-629-3p, miR-223-3p, and miR-142-3p was significantly upregulated in sputum of patients with severe asthma compared with that in healthy control subjects and was highest in patients with neutrophilic asthma. Expression of the 3 miRNAs was associated with sputum neutrophilia, and miR-223-3p and miR-142-3p expression was associated also with airway obstruction (FEV1/forced vital capacity). Expression of miR-629-3p was localized in the bronchial epithelium, whereas miR-223-3p and miR-142-3p were expressed in neutrophils, monocytes, and macrophages. Transfecting human bronchial epithelial cells with miR-629-3p mimic induced epithelial IL-8 mRNA and protein expression. IL-1beta and IL-8 protein levels were significantly increased in sputum of patients with severe asthma and were positively associated with sputum neutrophilia. CONCLUSIONS: Expression of miR-223-3p, miR-142-3p, and miR-629-3p is increased in sputum of patients with severe asthma and is linked to neutrophilic airway inflammation, suggesting that these miRNAs contribute to this asthma inflammatory phenotype. [less ▲]

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See detailLung-resident eosinophils represent a distinct regulatory eosinophil subset
Mesnil, Claire ULg; Raulier, Stéfanie ULg; Paulissen, G et al

in Journal of Clinical Investigation (2016), 126(9), 3275-3295

Increases in eosinophil numbers are associated with infection and allergic diseases, including asthma, but there is also evidence that eosinophils contribute to homeostatic immune processes. In mice, the ... [more ▼]

Increases in eosinophil numbers are associated with infection and allergic diseases, including asthma, but there is also evidence that eosinophils contribute to homeostatic immune processes. In mice, the normal lung contains resident eosinophils (rEos), but their function has not been characterized. Here, we have reported that steady-state pulmonary rEos are IL-5–independent parenchymal Siglec-FintCD62L+CD101lo cells with a ring-shaped nucleus. During house dust mite–induced airway allergy, rEos features remained unchanged, and rEos were accompanied by recruited inflammatory eosinophils (iEos), which were defined as IL-5–dependent peribronchial Siglec-FhiCD62L–CD101hi cells with a segmented nucleus. Gene expression analyses revealed a more regulatory profile for rEos than for iEos, and correspondingly, mice lacking lung rEos showed an increase in Th2 cell responses to inhaled allergens. Such elevation of Th2 responses was linked to the ability of rEos, but not iEos, to inhibit the maturation, and therefore the pro-Th2 function, of allergen-loaded DCs. Finally, we determined that the parenchymal rEos found in nonasthmatic human lungs (Siglec-8+CD62L+IL-3Rlo cells) were phenotypically distinct from the iEos isolated from the sputa of eosinophilic asthmatic patients (Siglec-8+CD62LloIL-3Rhi cells), suggesting that our findings in mice are relevant to humans. In conclusion, our data define lung rEos as a distinct eosinophil subset with key homeostatic functions. [less ▲]

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See detailA molecular approach for the rapid, selective and sensitive detection of Exophiala jeanselmei in environmental samples: development and performance assessment of a real-time PCR assay.
Libert, X.; Chasseur, C.; Packeu, A. et al

in Applied Microbiology and Biotechnology (2016), 100(3), 1377-1392

Exophiala jeanselmei is an opportunistic pathogenic black yeast growing in humid environments such as water reservoirs of air-conditioning systems. Because this fungal contaminant could be vaporized into ... [more ▼]

Exophiala jeanselmei is an opportunistic pathogenic black yeast growing in humid environments such as water reservoirs of air-conditioning systems. Because this fungal contaminant could be vaporized into the air and subsequently cause health problems, its monitoring is recommended. Currently, this monitoring is based on culture and microscopic identification which are complex, sometimes ambiguous and time-demanding, i.e., up to 21 days. Therefore, molecular, culture-independent methods could be more advantageous for the monitoring of E. jeanselmei. In this study, we developed a SYBR(R)green real-time PCR assay based on the internal transcribed spacer 2 from the 18S ribosomal DNA complex for the specific detection of E. jeanselmei. The selectivity (100 %), PCR efficiency (95.5 %), dynamic range and repeatability of this qPCR assay were subsequently evaluated. The limit of detection for this qPCR assay was determined to be 1 copy of genomic DNA of E. jeanselmei. Finally, water samples collected from cooling reservoirs were analyzed using this qPCR assay to deliver a proof of concept for the molecular detection of E. jeanselmei in environmental samples. The results obtained by molecular analysis were compared with those of classical methods (i.e., culture and microscopic identification) used in routine analysis and were 100 % matching. This comparison demonstrated that this SYBR(R)green qPCR assay can be used as a molecular alternative for monitoring and routine investigation of samples contaminated by E. jeanselmei, while eliminating the need for culturing and thereby considerably decreasing the required analysis time to 2 days. [less ▲]

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See detailEffect of a CpG-ODN on the innate immune system of the horse: an in-vivo trial
Tosi, Irène ULg; Pirottin, Dimitri ULg; Fievez, Laurence ULg et al

Poster (2015, October 16)

Oligodeoxynucleotides containing cytosine-phosphate-guanosine motifs (CpG-ODN) represent a class of agonists of Toll-like Receptor 9 (TLR9). TLR9 activation induces the secretion of cytokines and the ... [more ▼]

Oligodeoxynucleotides containing cytosine-phosphate-guanosine motifs (CpG-ODN) represent a class of agonists of Toll-like Receptor 9 (TLR9). TLR9 activation induces the secretion of cytokines and the maturation of immune cells, thus initiating both innate and adaptive immune responses. Therefore, CpG-ODN has been investigated in different species as a potential immune-modulator targeting infectious, allergic and neoplastic diseases. It has been administered by nebulisation to RAO-affected horses with promising results. Nonetheless, there is no in-vivo study on the effect of CpG administered systemically to the horse. Therefore, we tested the effect of CpG, given by intramuscular injection, on the equine immune response. Eight horses were used for this study. Five mg/horse were injected to 4 horses at D0 and D7; the other horses received a placebo (PBS). Blood was collected 2 days prior to each injection, then regularly up to D21. A clinical exam was realised daily. Laboratory analyses included haematology, ELISA tests for IFN-alpha, IFN-gamma, TNF-alpha and IL-10 and cytometry analyses for MCHII and CD86 expressions on B-lymphocytes. A cross-over of the 2 groups was realised after 2 months of washout. CpG was well tolerated. Significant transient eosinopenia, monocytosis and leukopenia were observed after CpG injection, while ELISA and cytometry analyses did not reveal any significant modification. This trial represents the first in-vivo study where CpG is administered systemically to healthy horses. Further studies are needed to adjust the dose, the formulation and the sampling schedule and to fully investigate this molecule as potentiel modulator of the equine immune system. [less ▲]

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See detailThe Innate Immune Response of Equine Bronchial Epithelial Cells is Altered by Training
Frellstedt, Linda ULg; Gosset, Philippe; Kervoaze, Gwenola et al

in Veterinary Research (2015), 46(3), 1-12

Respiratory diseases, including inflammatory airway disease (IAD), viral and bacterial infections, are common problems in exercising horses. The airway epithelium constitutes a major physical barrier ... [more ▼]

Respiratory diseases, including inflammatory airway disease (IAD), viral and bacterial infections, are common problems in exercising horses. The airway epithelium constitutes a major physical barrier against airborne infections and plays an essential role in the lung innate immune response mainly through toll-like receptor (TLR) activation. The aim of this study was to develop a model for the culture of equine bronchial epithelial cells (EBEC) in vitro and to explore EBEC innate immune responses in trained horses. Bronchial epithelial biopsies were taken from 6 adult horses during lower airway endoscopy. EBEC were grown in vitro by an explant method. The innate immune response of EBEC was evaluated in vitro by treatment with TLR ligands. TLR3 is the most strongly expressed TLR at the mRNA level in EBEC and stimulation of EBEC with Poly(I:C), an analog of viral dsRNA, triggers a strong secretion of IFN-β, TNF-α, IL-6 and CXCL8. We further evaluated the EBEC innate immune response in horses that underwent a 4-month-training program. While training had no effect on TLR mRNA expression in EBEC as well as in bronchial biopsies, it increased the production of IFN-β after stimulation with a TLR3 ligand and decreased the secretion of TNF-α and IL-6 after stimulation with a TLR2 and TLR3 ligand. These findings may be implicated in the increased risk for viral and bacterial infections observed in sport horses. Altogether, we report a successful model for the culture of EBEC that can be applied to the investigation of pathophysiologic conditions in longitudinal studies. [less ▲]

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See detailGeneration of a soluble recombinant trimeric form of bovine CD40L and its potential use as a vaccine adjuvant in cows
Pujol, Julien ULg; Bouillenne, Fabrice ULg; Farnir, Frédéric ULg et al

in Veterinary immunology and immunopathology (2015), 168(1), 1-13

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See detailDevelopment and performance assessment of a qualitative SYBR(R) green real-time PCR assay for the detection of Aspergillus versicolor in indoor air.
Libert, X.; Chasseur, C.; Bladt, S. et al

in Applied Microbiology and Biotechnology (2015), 99(17), 7267-7282

Currently, contamination of indoor environment by fungi and molds is considered as a public health problem. The monitoring of indoor airborne fungal contamination is a common tool to help understanding ... [more ▼]

Currently, contamination of indoor environment by fungi and molds is considered as a public health problem. The monitoring of indoor airborne fungal contamination is a common tool to help understanding the link between fungi in houses and respiratory problems. Classical analytical monitoring methods, based on cultivation and microscopic identification, depend on the growth of the fungi. Consequently, they are biased by difficulties to grow some species on certain culture media and under certain conditions or by noncultivable or dead fungi that can consequently not be identified. However, they could have an impact on human health as they might be allergenic. Since molecular methods do not require a culture step, they seem an excellent alternative for the monitoring of indoor fungal contaminations. As a case study, we developed a SYBR(R) green real-time PCR-based assay for the specific detection and identification of Aspergillus versicolor, which is frequently observed in indoor environment and known to be allergenic. The developed primers amplify a short region of the internal transcribed spacer 1 from the 18S ribosomal DNA complex. Subsequently, the performance of this quantitative polymerase chain reaction (qPCR) method was assessed using specific criteria, including an evaluation of the selectivity, PCR efficiency, dynamic range, and repeatability. The limit of detection was determined to be 1 or 2 copies of genomic DNA of A. versicolor. In order to demonstrate that this SYBR(R) green qPCR assay is a valuable alternative for monitoring indoor fungal contamination with A. versicolor, environmental samples collected in contaminated houses were analyzed and the results were compared to the ones obtained with the traditional methods. [less ▲]

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See detailExpression microarray as a tool to identify candidate blood biomarkers in horses suffering from inflammatory airway disease
Ramery, Eve ULg; Fraipont, Audrey ULg; Art, Tatiana ULg et al

in Veterinary Clinical Pathology (2015), 44(1), 37-46

Background: Inflammatory airway disease (IAD) affects performance and well-being in horses. Diagnosis is primarily reached by bronchoalveolar lavage (BAL) cytology but this is invasive and requires ... [more ▼]

Background: Inflammatory airway disease (IAD) affects performance and well-being in horses. Diagnosis is primarily reached by bronchoalveolar lavage (BAL) cytology but this is invasive and requires sedation. Objectives: The purpose of this study was to identify candidate blood biomarkers of IAD using species-specific expression microarrays. Methods: Horse Gene Expression Microarrays were used to investigate global mRNA expression in circulating leukocytes from healthy and IAD-affected standardbreds and endurance horses. Results: Nine genes were significantly differentially regulated in standardbreds and 61 in endurance horses (P < 0.001). These genes were mainly related to inflammation (eg. ALOX15B, PLA2G12B and PENK), oxidant/antioxidant balance (eg. DUOXA2 and GSTO1-1) and stress (eg. V1aR, GRLF1, Homer-2 and MAOB). DUOXA2, ALOX15B, PLA2G12B, MAOB and GRLF1 variations of expression were further validated by RT-qPCR. The deregulation of the oxidant/antioxidant balance was demonstrated at the protein level by an increase of glutathione peroxidase (GPx) activity in heparinised whole blood of IAD-affected standardbreds (P = 0.0025) and endurance horses (P = 0.0028). There was good correlation (r = 0.7354) between BAL neutrophil percentage and whole blood GPx activity in all horses. Conclusions: There is accumulating evidence that, even when systemic clinical signs are not evident, circulating leukocyte gene expression can reflect responses of other tissues, leading to potential diagnostic applications in the future. Although not specific for IAD, whole blood GPx activity appears to reflect BAL neutrophil percentage. This finding should be further assessed by testing a larger number of horses. [less ▲]

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See detailA gammaherpesvirus infection protects against allergic asthma.
Machiels, Bénédicte ULg; Dourcy, Mickael ULg; Sabatel, Catherine ULg et al

Poster (2014, December 12)

The “hygiene hypothesis” proposes that the augmentation of allergic diseases in developed countries could be linked to a reduced exposure to infections during childhood. Surprisingly, the potential ... [more ▼]

The “hygiene hypothesis” proposes that the augmentation of allergic diseases in developed countries could be linked to a reduced exposure to infections during childhood. Surprisingly, the potential protective role of herpesvirus infections against allergy development has never been addressed directly. In this study, we used the Murid herpesvirus 4 (MuHV-4) to study the impact of a persistent gammaherpesvirus infection on the development of House Dust Mites (HDM)-induced allergic asthma. Our results revealed that MuHV-4 infection affects both the sensitization and the challenging phases of HDM-induced airway allergy. In particular, we highlighted that MuHV-4 infection strongly impacts the lung innate immune response. Indeed, while the dendritic cells remained competent to uptake antigens and to migrate to the draining lymph nodes, MuHV-4 infection impaired their ability to trigger HDM sensitization. In the future, these results could allow us to develop strategies to prevent the development of TH2-skewed responses against respiratory allergens. [less ▲]

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See detailAntigen presenting cell-derived IL-6 restricts Th2-cell differentiation.
Mayer, Alice; Debuisson, Delphine; Denanglaire, Sebastien et al

in European Journal of Immunology (2014), 44(11), 3252-62

The identification of DC-derived signals orchestrating activation of Th1 and Th17 immune responses has advanced our understanding on how these inflammatory responses develop. However, whether specific ... [more ▼]

The identification of DC-derived signals orchestrating activation of Th1 and Th17 immune responses has advanced our understanding on how these inflammatory responses develop. However, whether specific signals delivered by DCs also participate in the regulation of Th2 immune responses remains largely unknown. In this study, we show that administration of antigen-loaded, IL-6-deficient DCs to naive mice induced an exacerbated Th2 response, characterized by the differentiation of GATA-3-expressing T lymphocytes secreting high levels of IL-4, IL-5, and IL-13. Coinjection of wild type and IL-6-deficient bone marrow-derived dendritic cells (BMDCs) confirmed that IL-6 exerted a dominant, negative influence on Th2-cell development. This finding was confirmed in vitro, where exogenously added IL-6 was found to limit IL-4-induced Th2-cell differentiation. iNKT cells were required for optimal Th2-cell differentiation in vivo although their activation occurred independently of IL-6 secretion by the BMDCs. Collectively, these observations identify IL-6 secretion as a major, unsuspected, mechanism whereby DCs control the magnitude of Th2 immunity. [less ▲]

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See detailTraining Modifies Innate Immune Responses in Blood Monocytes and in Pulmonary Alveolar Macrophages
Frellstedt, Linda ULg; Waldschmidt, Ingrid; Gosset, Philippe et al

in American Journal of Respiratory Cell and Molecular Biology (2014), 51(1), 135-142

In humans, strenuous exercise causes increased susceptibility to respiratory infections associated with down-regulated expression of Toll-like receptors (TLRs), co-stimulatory and antigen-presenting ... [more ▼]

In humans, strenuous exercise causes increased susceptibility to respiratory infections associated with down-regulated expression of Toll-like receptors (TLRs), co-stimulatory and antigen-presenting molecules. Lower airway diseases are also a common problem in sport and racing horses. Because the innate immunity plays an essential role in lung defense mechanisms, we aimed to assess the effect of acute exercise and training on innate immune responses in two different compartments. Blood monocytes and pulmonary alveolar macrophages (PAM) were collected from horses in an untrained, moderately and intensively trained as well as deconditioned state before and after a strenuous exercise test (SET). The cells were analysed for TLR mRNA expression by real-time PCR in vitro and the cytokine production after in vitro stimulation with TLR ligands was measured by ELISA. Our results showed that training, but not acute exercise, modified the innate immune responses in both compartments. The mRNA expression of TLR3 was down-regulated by training in both cell types, whereas the expression of TLR4 was up-regulated in monocytes. Monocytes treated with lipopolysaccharide (LPS) and a synthetic diacylated lipoprotein (FSL) showed increased cytokine secretion in trained and deconditioned subjects indicating the activation of cells at the systemic level. The production of TNF-alpha and IFN-beta in non-stimulated and stimulated PAM was decreased in trained and deconditioned horses and might therefore explain the increased susceptibility to respiratory infections. Our study reports a dissociation between the systemic and the lung response to training that is probably implicated in the systemic inflammation and in the pulmonary susceptibility to infection. [less ▲]

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