Related Articles 1{alpha},25-DIHYDROXY-VITAMIN D3 STIMULATION OF BRONCHIAL SMOOTH MUSCLE CELLS INDUCES AUTOCRINE, CONTRACTILITY AND REMODELLING PROCESSES. Physiol Genomics. 2007 Jan 9; Authors: Bossé Y, Maghni K, Hudson TJ Genetic variants in the vitamin D receptor (VDR) gene were recently associated with asthma. The biological mechanisms explaining this association is unknown, but are likely to involve many cell types given the pleiotropic effect of its ligand, 1alpha,25-dihydroxy-vitamin D3 [1alpha,25(OH)2D3]. Considering the prominent role of bronchial smooth muscle cells (BSMC) in the pathogenesis of asthma, experiments were conducted to explore the gene regulatory effects of 1alpha,25(OH)2D3 in these cells. First, it was shown that VDR is present both at the mRNA transcript and protein levels in human BSMC. The functionality of the receptor was then demonstrated by showing a more than 200-fold change in the expression of the 24-hydroxylase (CYP24A1) gene following 1alpha,25(OH)2D3 stimulation. Microarray experiments were then performed to identify differentially regulated genes and pathways in BMSC treated or not with 1alpha,25(OH)2D3. A total of 729 probe sets on the U133 plus 2.0 Affymetrix GeneChip showed fold-change differences above the 1.5 threshold using the Robust Multichip Average (RMA) intensities. This corresponds to 231 unique genes that were up-regulated and 215 unique genes that were down-regulated following 1alpha,25(OH)2D3 stimulation. Real-time PCR was performed to validate the microarray experiment and to confirm the regulation of asthma candidate genes. To identify the biological relevance of this regulation, biological pathways analyses were performed. The most significant network of up-regulated genes included genes involved in morphogenesis, cell growth and survival as well as genes encoding structural proteins, which are potentially involved in airway remodelling. Key words: microarray, real-time PCR, pathways analyses, candidate genes.
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Related Articles Smooth muscle myosin isoform expression and LC20 phosphorylation in innate rat airway hyperresponsiveness.
Related Articles CCR3 expression and function in asthmatic airway smooth muscle cells. J Immunol. 2005 Aug 15;175(4):2702-8 Authors: Joubert P, Lajoie-Kadoch S, Labonté I, Gounni AS, Maghni K, Wellemans V, Chakir J, Laviolette M, Hamid Q, Lamkhioued B Asthma is characterized by an increase in airway smooth muscle mass and a decreased distance between the smooth muscle layer and the epithelium. Furthermore, there is evidence to indicate that airway smooth muscle cells (ASMC) express a wide variety of receptors involved in the immune response. The aims of this study were to examine the expression of CCR3 on ASMC, to compare this expression between asthmatic and nonasthmatic subjects, and to determine the implications of CCR3 expression in the migration of ASMC. We first demonstrated that ASMC constitutively express CCR3 at both mRNA and protein levels. Interestingly, TNF-alpha increases ASMC surface expression of CCR3 from 33 to 74%. Furthermore, using FACS analysis, we found that ASMC CCR3 is expressed to a greater degree in asthmatic vs control subjects (95 vs 75%). Functionality of the receptor was demonstrated by calcium assay; the addition of CCR3 ligand eotaxin to ASMC resulted in an increase in intracellular calcium production. Interestingly, ASMC was seen to demonstrate a positive chemotactic response to eotaxin. Indeed, ASMC significantly migrated toward 100 ng/ml eotaxin (2.2-fold increase, compared with control). In conclusion, the expression of CCR3 by ASMC is increased in asthmatics, and our data show that a CCR3 ligand such as eotaxin induces migration of ASMC in vitro. These results may suggest that eotaxin could be involved in the increased smooth muscle mass observed in asthmatics through the activation of CCR3.
Related Articles The effects of extracellular purines and pyrimidines on human airway smooth muscle cells. J Pharmacol Exp Ther. 2005 Nov;315(2):941-8
Related Articles Role of airway eosinophilia and eosinophil activation in Sephadex-induced inflammation. Inflammation. 2004 Aug;28(4):195-206 Authors: Maghni K, Nantel F, Lanoue C, Cloutier S, Cristol JP, Cadieux A, Sirois P The effects of an intravenous injection of Sephadex beads on lung eosinophil infiltration and eosinophil peroxydase activity and its relationship to bronchial hyperresponsiveness was examined in guinea pigs. This Sephadex beads injection led to blood, lung and airway eosinophilia in association with bronchial hyperresponsiveness. Histologic examination of the lower bronchus indicated that the eosinophil number increased markedly in the mucosa and submucosa. In addition, the eosinophils surrounding the bronchioles 1 day after the Sephadex injection migrated further in airway submucosa and mucosa 7 and 14 days after. Moreover, the bronchial hyperresponsiveness is observed without histologic evidence of airway epithelium damage. Therefore, the bronchial hyperresponsiveness seems to be more related to the eosinophil infiltration in the airway epithelium and possibly eosinophil activation rather than to the eosinophil number recovered in the BAL fluid. We conclude that the maintenance of hyperresponsiveness state could be associated with the persistence of blood and airway eosinophilia.
Related Articles Conjugates of ovalbumin and monomethoxypolyethylene glycol abolish late allergic responses and decrease IL-4 and IL-5 mRNA expression in the rat. Pulm Pharmacol Ther. 2003;16(6):361-9 Authors: Lavoie JP, Maghni K, Taha R, Yang XX, Lang GM, Sehon AH, Hamid QA, Martin JG The purpose of this study was to test the therapeutic potential of monomethoxypolyethylene glycol (mPEG) conjugated-allergen using a rodent model of allergic asthma. Previously, this conjugate has been shown to possess the dual capacity of inducing long-term ovalbumin (OA)-specific suppression of the antibody response and inactivating rat mast cells that have been sensitized with murine IgE to OA. Ovalbumin sensitized and challenged Brown Norway rats were studied. Fourteen days after sensitization, a test group of six rats received mPEG-OA solution intratracheally and were challenged 30 min later with aerosolized OA. Another group of seven sensitized rats was similarly challenged with OA 30 min after intratracheal administration of normal saline. A group of six sensitized rats received mPEG-OA solution intratracheally but were challenged with normal saline. Another group of seven sensitized rats received mPEG-BSA solution intratracheally and were challenged 30 min later with aerosolized OA. A final group of five unsensitized rats were neither challenged nor medicated intratracheally. Pulmonary resistance was measured before and for 8 h following inhalation challenge. mPEG-OA treatment had an inhibitory effect on the allergic late airway response, but the early response was not significantly altered. Both mPEG-OA and mPEG-BSA reduced the total cells, eosinophils and neutrophils, in bronchoalveolar lavage and decreased the expression of IL-4, IL-5 and IFN-gamma mRNA. In conclusion, mPEG-OA can prevent the development of allergen-induced late airway responses and reduce airway Th2-type cytokine expression whereas mPEG conjugated to an irrelevant antigen (BSA) is anti-inflammatory but does not affect the late response.
Related Articles IL-13 may mediate allergen-induced hyperresponsiveness independently of IL-5 or eotaxin by effects on airway smooth muscle.
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Related Articles Inhibition of allergic airways inflammation and airway hyperresponsiveness in mice by dexamethasone: role of eosinophils, IL-5, eotaxin, and IL-13. J Allergy Clin Immunol. 2003 May;111(5):1049-61
Related Articles Time course of airway mechanics of the (+)insert myosin isoform knockout mouse. Am J Respir Cell Mol Biol. 2004 Mar;30(3):326-32
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Related Articles Chlorine-induced injury to the airways in mice. Am J Respir Crit Care Med. 2003 Sep 1;168(5):568-74 Authors: Martin JG, Campbell HR, Iijima H, Gautrin D, Malo JL, Eidelman DH, Hamid Q, Maghni K
Related Articles Involvement of the cysteinyl-leukotrienes in allergen-induced airway eosinophilia and hyperresponsiveness in the mouse. Am J Respir Cell Mol Biol. 2003 Jan;28(1):25-32
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Related Articles IFN-gamma secretion by CD8T cells inhibits allergen-induced airway eosinophilia but not late airway responses. J Allergy Clin Immunol. 2002 May;109(5):803-9
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Related Articles Therapeutic interventions aimed at reducing airway smooth muscle growth. Monaldi Arch Chest Dis. 2000 Aug;55(4):311-6 Authors: Martin JG, Greenstone EA, Maghni K The airways of asthmatic subjects undergo complex changes which affect all compartments of the airway wall. The airway smooth muscle (ASM) is particularly affected and is increased in mass. Both hyperplasia and hypertrophy probably contribute to the altered mass of muscle which is a potential cause of airway hyperresponsiveness. The impedance to smooth muscle shortening resulting from the constitutive properties of the airway wall and the elasticity of the parenchyma may be more easily overcome by the excess muscle of the asthmatic airway. The ASM may also undergo important changes in its functional characteristics as a result of allergic sensitization and challenge. Increases in maximal shortening velocity, phospholipase C activity and membrane potential are some of the changes in the characteristics of sensitized ASM. The ASM may also change its phenotype from a contractile to a secretory tissue in response to the stimulus of airway inflammation and in doing so may contribute to the inflammatory process itself. The current therapies for asthma have the potential to counter some of the adverse effects of airway modelling, in particular in so far as the ASM is concerned. These effects should be kept in mind when considering the rationale for effective maintenance therapy for asthma.
Related Articles Dichotomy between neurokinin receptor actions in modulating allergic airway responses in an animal model of helper T cell type 2 cytokine-associated inflammation.
Related Articles Role of cysteinyl leukotrienes in CD4(+) T cell-driven late allergic airway responses. J Pharmacol Exp Ther. 2000 May;293(2):410-6
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Related Articles Selective inflammatory response induced by intratracheal and intravenous administration of poly-L-arginine in guinea pig lungs. Inflammation. 1999 Jun;23(3):287-304 Authors: Arseneault D, Maghni K, Sirois P Major basic protein (MBP) is a cationic protein found in eosinophil granules that was postulated to participate in the pathogenesis of bronchial asthma. Recently, it has been demonstrated that MBP level in serum or bronchoalveolar lavage (BAL) fluid was correlated with bronchial hyperresponsiveness (BHR) in asthmatics. A number a studies have established that MBP actions could be mimicked by synthetic polycations as poly-L-arginine. In this study, we investigated the effects of intratracheal and intravenous administration of poly-L-arginine on lung inflammatory response development. The intratracheal injection of poly-L-arginine at the doses of 1, 10, 100 nmol/animal increased the number of eosinophils (up to 3.2 fold) and neutrophils (up to 12 fold) in BAL fluid. Eosinophil and neutrophil infiltration was reversed by 88% and 67% respectively following low molecular weight heparin treatment (500 microg/animal). The intravenous injection of increasing doses of poly-L-arginine (1, 10, 100, 500 nmol/animal) increased the number of eosinophils (up to 2.7 fold) but not neutrophil infiltration in guinea pig lungs. Eosinophil infiltration was reversed by 87% following low molecular weight heparin treatment (1.5 mg/animal). Intratracheal treatment with poly-L-arginine (100 nmol/animal) produced an important increase of beta-glucuronidase, histamine, eosinophil peroxidase (EPO) and albumin levels in BAL fluid, whereas the intravenous treatment (500 nmol/animal) did not. These results show that the route of administration of poly-L-arginine greatly influences its effect on inflammatory cell recruitment since both administration routes elicited eosinophil migration but only the intratracheal route stimulated the migration of neutrophils. Moreover, poly-L-arginine appeared to induce other inflammatory responses since it increased beta-glucuronidase, histamine, EPO and albumin levels in BAL fluid following intratracheal treatment. These results also showed that low molecular weight heparin significantly blocks the inflammatory responses elicited by poly-L-arginine.
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Related Articles Natural killer and lectin-dependent cytotoxic activities of Kurloff cells: target cell selectivity, conjugate formation, and Ca++ dependency. Inflammation. 1996 Dec;20(6):647-71 Authors: Pouliot N, Maghni K, Blanchette F, Cironi L, Sirois P, Stankova J, Rola-Pleszczynski M Kurloff cells may represent a major component of NK cell activity in the guinea pig. We have pursued to characterize the mechanism of their action. Using murine target cells, we found Kurloff cell cytotoxicity to be selective for the NK-sensitive YAC-1 target cell, with minimal activity against the NK-resistant P815 target cell. In the presence of PHA, but not ConA, cytotoxicity was markedly augmented against both YAC-1 and P815. While effector-target conjugate formation was observed with YAC-1 cells but not P815 cells in control cultures, it was augmented with both target cell types in cultures with PHA. Pretreatment alone with PHA was ineffective, however. NK cell activity of Kurloff cells was dependent on extracellular Ca++ and entry of Ca++ into the effector cells, as demonstrated by abrogation of cytotoxicity when extracellular Ca++ was chelated with EDTA or EGTA, or following treatment with the Ca++ channel blockers verapamil and diltiazem. Furthermore, inhibition of PKC by H7 resulted in significant reduction of Kurloff cell-mediated NK activity, while pretreatment of effector cells with the PKC activator TPA enhanced NK activity. Kurloff cells could also be stimulated to produce serine esterases by contact with target cells or treatment with phorbol ester and ionophore. Finally, a majority of Kurloff cells, identified by the monoclonal antibody 14D1, reacted with the human NK cell marker CD56. Taken together, these data suggest that Kurloff cells have NK-like characteristics and activity, with target cell selectivity, and that their lytic mechanisms involve influx of extracellular Ca++, PKC activation and serine esterase production.
Related Articles Kinetics of eosinophilia and eosinophil activation in the development of non-allergic bronchial hyperresponsiveness in guinea pigs injected with Sephadex beads. Inflammation. 1996 Oct;20(5):523-35 Authors: Maghni K, Simard MJ, Arseneault D, Sirois P Eosinophils are believed to play a crucial role in the pathogenesis of airway hyperresponsiveness (AHR). In the present study, the involvement of blood and pulmonary eosinophilia as well as the eosinophil activation in the onset of non-allergic AHR caused by the injection of G-50 Sephadex beads in guinea pigs was investigated. Reactivity of the isolated lower bronchus to histamine was measured ex vivo in a bioassay system. The increase of reactivity of the isolated lower bronchus of Sephadex-injected animals to histamine was observed as early as 3 h after the Sephadex injection and was maximal between 6-24 h. Sephadex-induced blood eosinophilia was characterized by two successive increases of blood eosinophil counts peaking at 3 and 12 h respectively. The recruitment of inflammatory cells into the lungs as measured in bronchoalveolar lavage fluid (BALF) have shown that the neutrophils were initially increased at 3 h whereas the number of eosinophils increased only 6 h after the bead injection; both cell populations were maximal 24 h later. Eosinophil peroxidase (EPO) activity was used as a marker for the apparent number of eosinophils in airways and the degree of activation of eosinophils recovered in BALF. Results have shown that EPO activity in the lower bronchus of Sephadex-injected animals increased at 6 h, decreased at 12 h and was maximal 24 h later. The EPO activity recovered in BALF was maximal between 6 to 24 h after the bead injection in guinea pigs. Correlation between the number of eosinophils and the EPO activity in BALF suggests that BALF eosinophils have been activated and have degranulated in airways. Correlation studies also indicated that both Sephadex induced blood eosinophilia and eosinophil activation were associated to the development of AHR. In contrast, the increase of EPO activity in the lower bronchus and BALF eosinophilia were not correlated to the development of AHR in our model. In conclusion, our results suggest that Sephadex induced non-allergic AHR in guinea pigs could be related, at least in part, to blood eosinophilia and eosinophil activation. Whether blood, airway and BALF eosinophilia as well as eosinophil activation are relevant factors to determine the potential role of eosinophils in the pathogenesis of AHR is discussed.