55 research outputs found

    Update on Glucocorticoid Receptor Regulation

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    SIDA y discriminación en el área laboral

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    Laura Pujols Subero: Abogada dominicana. Fue consultora jurídica del Consejo Presidencial del SIDA (COPRESIDA).Este texto plantea el problema del estigma y la discriminación sociolaboral a que son sometidas las personas infectadas con el VIH-SIDA. Como resultado de ello, el respeto y cumplimiento de los derechos humanos, así como del estado de derecho, se ven seriamente mermados. En el caso de las personas portadoras del virus o enfermas del SIDA, el rechazo que sufren las sumen en un silencio generalizado que les impide exigir sus derechos libremente y que provoca también que sea más difícil controlar o impedir la expansión o contagio de la enfermedad. Este documento cierra con las iniciativas legislativas dominicanas destinadas a impedir la violación de los derechos humanos y ciudadanos de las personas infectadas, así como con algunos apuntes sobre el Consejo Presidencial del SIDA (COPRESIDA), entidad encargada de trazar las políticas estatales para tratar todo lo relativo a esta enfermedad

    Activity of the cyclooxygenase 2-prostaglandin-E prostanoid receptor pathway in mice exposed to house dust mite aeroallergens, and impact of exogenous prostaglandin E2

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    <p>Abstract</p> <p>Background</p> <p>Prostaglandin E<sub>2 </sub>(PGE<sub>2</sub>), experimentally administered to asthma patients or assayed in murine models, improves allergen-driven airway inflammation. The mechanisms are unknown, but fluctuations of the endogenous cyclooxygenase (COX)-2/prostaglandin/E prostanoid (EP) receptor pathway activity likely contribute to the clinical outcome. We analyzed the activity of the pathway in mice sensitized to aeroallergens, and then studied its modulation under exogenous PGE<sub>2</sub>.</p> <p>Methods</p> <p>Mice were exposed to house dust mite (HDM) aeroallergens, a model that enable us to mimic the development of allergic asthma in humans, and were then treated with either subcutaneous PGE<sub>2 </sub>or the selective EP1/3 receptor agonist sulprostone. Simultaneously with airway responsiveness and inflammation, lung COX-2 and EP receptor mRNA expression were assessed. Levels of PGE<sub>2</sub>, PGI<sub>2</sub>, PGD<sub>2 </sub>were also determined in bronchoalveolar lavage fluid.</p> <p>Results</p> <p>HDM-induced airway hyperreactivity and inflammation were accompanied by increased COX-2 mRNA production. In parallel, airway PGE<sub>2 </sub>and PGI<sub>2</sub>, but not PGD<sub>2</sub>, were upregulated, and the EP2 receptor showed overexpression. Subcutaneous PGE<sub>2 </sub>attenuated aeroallergen-driven airway eosinophilic inflammation and reduced endogenous PGE<sub>2 </sub>and PGI<sub>2 </sub>production. Sulprostone had neither an effect on airway responsiveness or inflammation nor diminished allergen-induced COX-2 and PGE<sub>2 </sub>overexpression. Finally, lung EP2 receptor levels remained high in mice treated with PGE<sub>2</sub>, but not in those treated with sulprostone.</p> <p>Conclusion</p> <p>The lung COX-2/PGE<sub>2</sub>/EP2 receptor pathway is upregulated in HDM-exposed mice, possibly as an effort to attenuate allergen-induced airway inflammation. Exogenous PGE<sub>2 </sub>downregulates its endogenous counterpart but maintains EP2 overexpression, a phenomenon that might be required for administered PGE<sub>2 </sub>to exert its protective effect.</p

    Effect of lipopolysaccharide on glucocorticoid receptor function in control nasal mucosa fibroblasts and in fibroblasts from patients with chronic rhinosinusitis with nasal polyps and asthma

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    Chronic rhinosinusitis with nasal polyps (CRSwNP) is a chronic inflammatory disease of the upper airways frequently associated with asthma. Bacterial infection is a feature of CRSwNP that can aggravate the disease and the response to glucocorticoid treatment.We examined whether the bacterial product lipopolysaccharide (LPS) reduces glucocorticoid receptor (GR) function in control nasal mucosa (NM) fibroblasts and in nasal polyp (NP) fibroblasts from patients with CRSwNP and asthma.NP (n = 12) and NM fibroblasts (n = 10) were in vitro pre-incubated with LPS (24 hours) prior to the addition of dexamethasone. Cytokine/chemokine secretion was measured by ELISA and Cytometric Bead Array. GR?, GR?, mitogen-activated protein-kinase phosphatase-1 (MKP-1) and glucocorticoid-induced leucine zipper (GILZ) expression was measured by RT-PCR and immunoblotting, GR? nuclear translocation by immunocytochemistry, and GR? localization by immunoblotting. The role of MKP-1 and GILZ on dexamethasone-mediated cytokine inhibition was analyzed by small interfering RNA silencing.Pre-incubation of nasal fibroblasts with LPS enhanced the secretion of IL-6, CXCL8, RANTES, and GM-CSF induced by FBS. FBS-induced CXCL8 secretion was higher in NP than in NM fibroblasts. LPS effects on IL-6 and CXCL8 were mediated via activation of p38?/? MAPK and IKK/NF-?B pathways. Additionally, LPS pre-incubation: 1) reduced dexamethasone's capacity to inhibit FBS-induced IL-6, CXCL8 and RANTES, 2) reduced dexamethasone-induced GR? nuclear translocation (only in NM fibroblasts), 3) did not alter GR?/GR? expression, 4) decreased GILZ expression, and 5) did not affect dexamethasone's capacity to induce MKP-1 and GILZ expression. MKP-1 knockdown reduced dexamethasone's capacity to suppress FBS-induced CXCL8 release.The bacterial product LPS negatively affects GR function in control NM and NP fibroblasts by interfering with the capacity of the activated receptor to inhibit the production of pro-inflammatory mediators. This study contributes to the understanding of how bacterial infection of the upper airways may limit the efficacy of glucocorticoid treatment

    Signal transduction pathways (MAPKS, NF-kB, and C/EBP) regulating COX-2 expression in nasal fibroblasts from asthma patients with aspirin intolerance

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    Background Recent studies have revealed that cyclooxygenase-2 (COX-2) expression is down-regulated in aspirin-induced asthma (AIA). Various signal pathways (MAPKs, NF-κB and C/EBP) are involved in COX-2 regulation. Objective To investigate the regulation of COX-2 expression through MAP-kinase pathway activation and nuclear factor translocation in aspirin-induced asthma (AIA). Methods Fibroblasts were isolated from specimens of nasal mucosa (NM, N = 5) and nasal polyps (NP, N = 5). After IL-1β (1 ng/ml) incubation, COX-2 and phosphorylated forms of ERK, JNK and p38 MAPK were measured by Western blot. MAPK's role in IL-1β-induced COX-2 expression was assessed by treating cells with ERK (PD98059), JNK (SP600125) and p38 MAPK (SB203580) inhibitors (0.1-10 µM) prior to IL-1β exposure. NF-κB and C/EBP nuclear translocation was measured by Western blot and TransAM® after IL-1β (10 ng/ml) exposure. Results No differences were observed in the MAPK phosphorylation time-course between NM and NP-AIA fibroblasts. The p38 MAPK inhibitor at 10 µM significantly reduced IL-1β-induced COX-2 expression in NM fibroblasts (85%). In NP-AIA fibroblasts the COX-2 inhibition (65%) at 1 and 10 µM was not statistically significant compared to non-treated cells. ERK and JNK inhibitors had no significant effect in either the NM or NP-AIA cultures. The effect of IL-1β on NF-κB and C/EBP subunits' nuclear translocation was similar between NM and NP-AIA fibroblasts. Conclusions These results suggest that p38 MAPK is the only MAPK involved in IL-1β-induced COX-2 expression. NM and NP-AIA fibroblasts have similar MAPK phosphorylation dynamics and nuclear factor translocation (NF-κB and C/EBP). COX-2 downregulation observed in AIA patients appears not to be caused by differences in MAPK dynamics or transcription factor translocation

    Lung Myofibroblasts Are Characterized by DownRegulated Cyclooxygenase-2 and Its Main Metabolite, Prostaglandin E2

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    Background: Prostaglandin E2 (PGE(2)), the main metabolite of cyclooxygenase (COX), is a well-known anti-fibrotic agent. Moreover, myofibroblasts expressing alpha-smooth muscle actin (alpha-SMA), fibroblast expansion and epithelial-mesenchymal transition (EMT) are critical to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Our aim was to investigate the expression of COX-2 and PGE(2) in human lung myofibroblasts and establish whether fibroblast-myofibroblast transition (FMT) and EMT are associated with COX-2 and PGE(2) down-regulation. Methods: Fibroblasts obtained from IPF patients (n = 6) and patients undergoing spontaneous pneumothorax (control, n = 6) and alveolar epithelial cell line A549 were incubated with TGF-beta 1 and FMT and EMT markers were evaluated. COX-2 and alpha-SMA expression, PGE(2) secretion and cell proliferation were measured after IL-1 beta and PGE(2) incubation. Results: Myofibroblasts from both control and IPF fibroblast cultures stimulated with IL-1 beta showed no COX-2 expression. IPF fibroblasts showed increased myofibroblast population and reduced COX-2 expression in response to IL-1 beta. TGF-beta 1 increased the number of myofibroblasts in a time-dependent manner. In contrast, TGF-beta 1 induced slight COX-2 expression at 4 h (without increase in myofibroblasts) and 24 h, but not at 72 h. Both IPF and control cultures incubated with TGF-beta 1 for 72 h showed diminished COX-2 induction, PGE(2) secretion and alpha-SMA expression after IL-1 beta addition. The latter decreased proliferation in fibroblasts but not in myofibroblasts. A549 cells incubated with TGF-beta 1 for 72 h showed down-regulated COX-2 expression and low basal PGE(2) secretion in response to IL-1 beta. Immuno-histochemical analysis of IPF lung tissue showed no COX-2 immuno-reactivity in myofibroblast foci. Conclusions: Myofibroblasts are associated with COX-2 down-regulation and reduced PGE(2) production, which could be crucial in IPF development and progression

    Superior effect of MP-AzeFlu than azelastine or fluticasone propionate alone on reducing inflammatory markers

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    Background: MP-AzeFlu, intranasal formulation of azelastine hydrochloride (AZE) and fluticasone propionate (FP), is superior to AZE or FP alone for treatment of allergic rhinitis (AR). However, the precise anti-inflammatory mechanism of action of MP-AzeFlu has not been characterized. Objective: To investigate the anti-inflammatory effects of MP-AzeFlu compared with AZE or FP alone in an established in vitro model of eosinophilic inflammation. Methods: Nasal mucosal epithelial cells and peripheral blood eosinophils were obtained from human volunteers. Epithelial cells were stimulated with 10% fetal bovine serum (FBS) in the presence of MP-AzeFlu, AZE, or FP (1:102 to 1:105 dilution). Concentrations of interleukin (IL)-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were measured by ELISA. Eosinophils were incubated in 10% human epithelial cell-conditioned medium (HECM) and survival assessed by trypan blue dye exclusion. Results are expressed as mean ± SEM percentage secretion/survival compared with FBS/HECM (respectively). Results: FP and MP-AzeFlu (all dilutions) and AZE (1:102) significantly reduced IL-6 secretion and eosinophil survival compared with positive controls. At 1:102 dilution, IL-6 secretion was significantly lower with MP-AzeFlu (38.3 ± 4.2%, compared with FBS = 100%) than with AZE (76.1 ± 4.9%) or FP (53.0 ± 4.9%). At 1:102 dilution, eosinophil survival was significantly lower with MP-AzeFlu at day 3 (17.5 ± 3.0%) and day 4 (2.4 ± 1.4%, compared with HECM = 100%) than with AZE (day 3: 75.2 ± 7.2%; day 4: 44.0 ± 9.7%) or FP (day 3: 38.5 ± 3.5%; day 4: 14.6 ± 4.0%). Conclusion: Greater reductions in cytokine secretion and eosinophil survival observed with MP-AzeFlu in vitro may underlie MP-AzeFlu's superior clinical efficacy vs. AZE or FP alone observed in AR patients
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