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Saint-André-lez-Lille, France

Frellstedt L.,University of Liege | Frellstedt L.,National Veterinary School of Alfort | Frellstedt L.,Institute Federatif Of Recherche 142 | Waldschmidt I.,National Veterinary School of Alfort | And 15 more authors.
American Journal of Respiratory Cell and Molecular Biology | Year: 2014

In humans, strenuous exercise causes increased susceptibility to respiratory infections associated with down-regulated expression of Toll-like receptors (TLRs) and costimulatory and antigen-presenting molecules. Lower airway diseases are also a common problem in sport and racing horses. Because innate immunity plays an essential role in lung defense mechanisms, we assessed the effect of acute exercise and training on innate immune responses in two different compartments. Blood monocytes and pulmonary alveolar macrophages (PAMs) were collected from horses in untrained, moderately trained, intensively trained, and deconditioned states before and after a strenuous exercise test. The cells were analyzed for TLR messenger ribonucleic acid (mRNA) expression by real-time PCR in vitro, and 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 LPS and a synthetic diacylated lipoprotein showed increased cytokine secretion in trained and deconditioned subjects, indicating the activation of cells at the systemic level. The production of TNF-α and IFN-β in nonstimulated and stimulated PAMs 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. Copyright © 2014 by the American Thoracic Society.

Deprez-Poulain R.,Institute Pasteur Of Lille | Deprez-Poulain R.,Institut Universitaire de France | Deprez-Poulain R.,French Institute of Health and Medical Research | Deprez-Poulain R.,Institute Federatif Of Recherche 142 | And 87 more authors.
Nature Communications | Year: 2015

Insulin-degrading enzyme (IDE) is a protease that cleaves insulin and other bioactive peptides such as amyloid-β. Knockout and genetic studies have linked IDE to Alzheimer's disease and type-2 diabetes. As the major insulin-degrading protease, IDE is a candidate drug target in diabetes. Here we have used kinetic target-guided synthesis to design the first catalytic site inhibitor of IDE suitable for in vivo studies (BDM44768). Crystallographic and small angle X-ray scattering analyses show that it locks IDE in a closed conformation. Among a panel of metalloproteases, BDM44768 selectively inhibits IDE. Acute treatment of mice with BDM44768 increases insulin signalling and surprisingly impairs glucose tolerance in an IDE-dependent manner. These results confirm that IDE is involved in pathways that modulate short-term glucose homeostasis, but casts doubt on the general usefulness of the inhibition of IDE catalytic activity to treat diabetes. © 2015 Macmillan Publishers Limited. All rights reserved.

Paget C.,Peter MacCallum Cancer Center | Paget C.,University of Melbourne | Paget C.,Institute Pasteur Of Lille | Paget C.,French Institute of Health and Medical Research | And 8 more authors.
Mucosal Immunology | Year: 2013

Mucosal sites are populated by a multitude of innate lymphoid cells and "innate-like" T lymphocytes expressing semiconserved T-cell receptors. Among the latter group, interest in type I natural killer T (NKT) cells has gained considerable momentum over the last decade. Exposure to NKT cell antigens is likely to occur continuously at mucosal sites. For this reason, and as they rapidly respond to stress-induced environmental cytokines, NKT cells are important contributors to immune and inflammatory responses. Here, we review the dual role of mucosal NKT cells during immune responses and pathologies with a particular focus on the lungs. Their role during pulmonary acute and chronic inflammation and respiratory infections is outlined. Whether NKT cells might provide a future attractive therapeutic target for treating human respiratory diseases is discussed.

Pichavant M.,Institute Pasteur Of Lille | Pichavant M.,University of Lille Nord de France | Pichavant M.,French National Center for Scientific Research | Pichavant M.,French Institute of Health and Medical Research | And 43 more authors.
EBioMedicine | Year: 2015

Progression of chronic obstructive pulmonary disease (COPD) is linked to episodes of exacerbations caused by bacterial infections due to Streptococcus pneumoniae. Our objective was to identify during COPD, factors of susceptibility to bacterial infections among cytokine network and their role in COPD exacerbations. S. pneumoniae was used to sub-lethally challenge mice chronically exposed to air or cigarette smoke (CS) and to stimulate peripheral blood mononuclear cells (PBMC) from non-smokers, smokers and COPD patients. The immune response and the cytokine production were evaluated. Delayed clearance of the bacteria and stronger lung inflammation observed in infected CS-exposed mice were associated with an altered production of IL-17 and IL-22 by innate immune cells. This defect was related to a reduced production of IL-1β and IL-23 by antigen presenting cells. Importantly, supplementation with recombinant IL-22 restored bacterial clearance in CS-exposed mice and limited lung alteration. In contrast with non-smokers, blood NK and NKT cells from COPD patients failed to increase IL-17 and IL-22 levels in response to S. pneumoniae, in association with a defect in IL-1β and IL-23 secretion. This study identified IL-17 and IL-22 as susceptibility factors in COPD exacerbation. Therefore targeting such cytokines could represent a potent strategy to control COPD exacerbation. © 2015 The Authors.

Paget C.,French Institute of Health and Medical Research | Paget C.,University of Lille Nord de France | Paget C.,French National Center for Scientific Research | Paget C.,Institute Federatif Of Recherche 142 | And 36 more authors.
Journal of Biological Chemistry | Year: 2012

Invariant natural killer T (iNKT) cells are non-conventional lipid-reactive αβ T lymphocytes that play a key role in host responses during viral infections, in particular through the swift production of cytokines. Their beneficial role during experimental influenza A virus (IAV) infection has recently been proposed, although the mechanisms involved remain elusive. Here we show that during in vivo IAV infection, mouse pulmonary iNKT cells produce IFN-γ and IL-22, a Th17-related cytokine critical in mucosal immunity. Although permissive to viral replication, IL-22 production by iNKT cells is not due to IAV infection per se of these cells but is indirectly mediated by IAV-infected dendritic cells (DCs). We show that activation of the viral RNA sensors TLR7 and RIG-I in DCs is important for triggering IL-22 secretion by iNKT cells, whereas the NOD-like receptors NOD2 and NLRP3 are dispensable. Invariant NKTcells respond to IL-1β and IL-23 provided by infected DCs independently of the CD1d molecule to release IL-22. In vitro, IL-22 protects IAV-infected airway epithelial cells against mortality but has no role on viral replication. Finally, during early IAV infection, IL-22 plays a positive role in the control of lung epithelial damages. Overall, IAV infection of DCs activates iNKT cells, providing a rapid source of IL-22 that might be beneficial to preserve the lung epithelium integrity. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.

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