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Dive into the research topics where Fabrice Jaspar is active.

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Featured researches published by Fabrice Jaspar.


Journal of Immunology | 2008

Dendritic Cells Genetically Engineered to Express IL-10 Induce Long-Lasting Antigen-Specific Tolerance in Experimental Asthma

Emmanuelle Henry; Christophe Desmet; Virginie Garzé; Laurence Fievez; Denis Bedoret; Carlo Heirman; Pedro Faísca; Fabrice Jaspar; Philippe Gosset; Alain Jacquet; Daniel Desmecht; Kris Thielemans; Pierre Lekeux; Muriel Moser; Fabrice Bureau

Dendritic cells (DCs) are professional APCs that have a unique capacity to initiate primary immune responses, including tolerogenic responses. We have genetically engineered bone marrow-derived DCs to express the immunosuppressive cytokine IL-10 and tested the ability of these cells to control experimental asthma. A single intratracheal injection of OVA-pulsed IL-10-transduced DCs (OVA-IL-10-DCs) to naive mice before OVA sensitization and challenge prevented all of the cardinal features of airway allergy, namely, eosinophilic airway inflammation, airway hyperreactivity, and production of mucus, Ag-specific Igs, and IL-4. OVA-IL-10-DCs also reversed established experimental asthma and had long-lasting and Ag-specific effects. We furthermore showed, by using IL-10-deficient mice, that host IL-10 is required for mediating the immunomodulatory effects of OVA-IL-10-DCs and demonstrated a significant increase in the percentage of OVA-specific CD4+CD25+Foxp3+IL-10+ regulatory T cells in the mediastinal lymph nodes of OVA-IL-10-DC-injected mice. Finally, adoptive transfer of CD4+ mediastinal lymph node T cells from mice injected with OVA-IL-10-DCs protected OVA-sensitized recipients from airway eosinophilia upon OVA provocation. Our study describes a promising strategy to induce long-lasting Ag-specific tolerance in airway allergy.


Journal of Veterinary Internal Medicine | 2006

Effect of Beclomethasone Dipropionate and Dexamethasone Isonicotinate on Lung Function, Bronchoalveolar Lavage Fluid Cytology, and Transcription Factor Expression in Airways of Horses with Recurrent Airway Obstruction

Laurent L. Couëtil; Tatiana Art; Brieuc De Moffarts; M. Becker; Dorothée Mélotte; Fabrice Jaspar; Fabrice Bureau; Pierre Lekeux

Glucocorticoid (GC) therapy is recognized to be effective for the treatment of recurrent airway obstruction (RAO) in horses. Anti-inflammatory properties of GC are thought to be mediated by suppression of inflammatory gene expression via inhibition of transcription factors such as nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). The purpose of this study was to evaluate the effect of low-dose inhaled beclomethasone dipropionate and injectable dexamethasone 21-isonicotinate on clinical signs, pulmonary function, airway cytology, and activity of NF-kappaB and AP-1 in bronchial cells of RAO-affected horses. Seven horses with RAO were exposed to moldy hay until they developed airway obstruction on 3 separate occasions. In a crossover design, they were then treated with a placebo (injection on day 1), inhaled beclomethasone (500 microg q12h for 10 days), or dexamethasone (0.06 mg/kg, IM on day 1) and monitored for 10 days. Pulmonary function, bronchoalveolar lavage fluid cytology, and NF-kappaB and AP-1 activity in bronchial brushing cells were measured before (day 1) and after treatment (day 10). Treatment with beclomethasone resulted in significantly improved pulmonary function of RAO-affected horses compared with placebo and dexamethasone treatments. However, none of the treatments had an effect on bronchoalveolar lavage fluid cytology or NF-kappaB and AP-1 activity. These findings reveal that, in a model of severe RAO, the benefits of low-dose inhaled beclomethasone on pulmonary function are not accompanied by a decrease in airway inflammatory cells or a suppression of transcription factors NF-kappaB and AP-1 DNA-binding activity.


Journal of Immunology | 2002

A proinflammatory role for the cyclopentenone prostaglandins at low micromolar concentrations: Oxidative stress-induced extracellular signal-regulated kinase activation without NF-kappa B inhibition

Fabrice Bureau; Christophe Desmet; Dorothée Mélotte; Fabrice Jaspar; Cédric Volanti; Alain Vanderplasschen; Paul-Pierre Pastoret; Jacques Piette; Pierre Lekeux

An anti-inflammatory role and therapeutic potential for cyclopentenone PGs (cyPGs) has been suggested, based on observations that levels of cyPGs in exudates increase during the resolution phase of inflammation, and that exogenous cyPGs may attenuate the inflammatory response in vivo and in vitro mainly through inhibition of NF-κB, a critical activator of inflammatory gene expression. However, exogenous cyPGs inhibit NF-κB only at concentrations substantially higher than those of endogenous cyPGs present in inflammatory fluids, thus challenging the hypothesis that cyPGs are naturally occurring inhibitors of inflammation and suggesting that cyPGs at low concentrations might have previously unappreciated effects. In this study, using various cell types, we report that cyPGs, when used at concentrations substantially lower than required for NF-κB inhibition (viz, low micromolar concentrations), significantly potentiate the inflammatory response to TNF-α. At these concentrations, cyPGs induce production of reactive oxygen species, thereby synergizing with TNF-α to activate the extracellular signal-regulated kinase 1/2, an activation which in turn potentiates proinflammatory cytokine expression at both transcriptional and posttranscriptional levels. Our study establishes a proinflammatory role for cyPGs at low micromolar concentrations, raises the possibility that cyPGs do not act as physiologic anti-inflammatory mediators, and questions the therapeutic potential of these compounds.


PLOS ONE | 2007

STAT5 Is an Ambivalent Regulator of Neutrophil Homeostasis

Laurence Fievez; Christophe Desmet; Emmanuelle Henry; Bernard Pajak; Silke Hegenbarth; Virginie Garzé; Françoise Bex; Fabrice Jaspar; Philippe Boutet; Laurent Gillet; Alain Vanderplasschen; Percy A. Knolle; Oberdan Leo; Muriel Moser; Pierre Lekeux; Fabrice Bureau

Background Although STAT5 promotes survival of hematopoietic progenitors, STAT5−/− mice develop mild neutrophilia. Methodology/Principal findings Here, we show that in STAT5−/− mice, liver endothelial cells (LECs) autonomously secrete high amounts of G-CSF, allowing myeloid progenitors to overcompensate for their intrinsic survival defect. However, when injected with pro-inflammatory cytokines, mutant mice cannot further increase neutrophil production, display a severe deficiency in peripheral neutrophil survival, and are therefore unable to maintain neutrophil homeostasis. In wild-type mice, inflammatory stimulation induces rapid STAT5 degradation in LECs, G-CSF production by LECs and other cell types, and then sustained mobilization and expansion of long-lived neutrophils. Conclusion We conclude that STAT5 is an ambivalent factor. In cells of the granulocytic lineage, it exerts an antiapoptotic function that is required for maintenance of neutrophil homeostasis, especially during the inflammatory response. In LECs, STAT5 negatively regulates granulopoiesis by directly or indirectly repressing G-CSF expression. Removal of this STAT5-imposed brake contributes to induction of emergency granulopoiesis.


Free Radical Biology and Medicine | 2001

IMPAIRED ACCUMULATION OF GRANULOCYTES IN THE LUNG DURING OZONE ADAPTATION

Laurence Fievez; Nathalie Kirschvink; S. Dogné; Fabrice Jaspar; Marie-Paule Merville; Vincent Bours; Pierre Lekeux; Fabrice Bureau

Respiratory alterations induced by an acute exposure to ozone (O(3)) paradoxically resolve during multiday exposure. This adaptation is characteristically accompanied by a gradual attenuation of lung neutrophilia. As maintenance of neutrophilia at the site of inflammation is due to cytokine-mediated delayed neutrophil apoptosis, which is associated with reduced levels of Bax, a proapoptotic protein, we sought to determine whether defects in these mechanisms could account for O(3) adaptation. Lung granulocytes obtained at different time points from calves exposed to 0.75 ppm O(3) for 12 h/d for 7 consecutive days neither showed enhancement of survival nor Bax deficiency, when compared to blood granulocytes. To further investigate the effects of an exogenous oxidative stress on neutrophil survival, human granulocytes were treated with hydrogen peroxide alone, or in combination with granulocyte/macrophage colony-stimulating factor, an antiapoptotic cytokine. Both treatments led to rapid apoptosis associated with downregulation of Bcl-x(L) and Bcl-2, two antiapoptotic proteins. This study shows that O(3) adaptation is associated with a failure in the mechanisms leading to accumulation of neutrophils at the site of inflammation, and suggests that this defect is due to direct proapoptotic effects of exogenous oxidative stress on granulocytes.


Blood | 2002

Constitutive nuclear factor-kappa B activity preserves homeostasis of quiescent mature lymphocytes and granulocytes by controlling the expression of distinct Bcl-2 family proteins

Fabrice Bureau; Alain Vanderplasschen; Fabrice Jaspar; Frédéric Minner; Paul-Pierre Pastoret; Marie-Paule Merville; Vincent Bours; Pierre Lekeux


The Journal of Allergy and Clinical Immunology | 2002

CD40 engagement enhances eosinophil survival through induction of cellular inhibitor of apoptosis protein 2 expression: Possible involvement in allergic inflammation☆☆☆★

Fabrice Bureau; Grégory Seumois; Fabrice Jaspar; Alain Vanderplasschen; Bruno Detry; Paul-Pierre Pastoret; Renaud Louis; Pierre Lekeux


Veterinary Microbiology | 2007

Helenalin reduces Staphylococcus aureus infection in vitro and in vivo

Delphine Boulanger; E. Brouillette; Fabrice Jaspar; F. Malouin; Jacques Mainil; Fabrice Bureau; Pierre Lekeux


American Journal of Respiratory and Critical Care Medicine | 2005

Treatment of Experimental Asthma by Decoy-mediated Local Inhibition of Activator Protein-1

Christophe Desmet; Philippe Gosset; Emmanuelle Henry; Virginie Garzé; Pedro Faísca; Nanda Vos; Fabrice Jaspar; Dorothée Mélotte; Bart N. Lambrecht; Daniel Desmecht; Bernard Pajak; Muriel Moser; Pierre Lekeux; Fabrice Bureau


Veterinary Immunology and Immunopathology | 2006

DNA binding activity of transcription factors in bronchial cells of horses with recurrent airway obstruction.

Laurent L. Couëtil; Tatiana Art; Brieuc De Moffarts; M. Becker; Dorothée Mélotte; Fabrice Jaspar; Fabrice Bureau; Pierre Lekeux

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Emmanuelle Henry

Université libre de Bruxelles

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