Inhibition of adhesion molecules by budesonide on a human epithelial cell line (lung carcinoma)

Plasmacytoid dendritic cells in allergic asthma and the role of inhaled corticosteroid treatment

BACKGROUND

Plasmacytoid dendritic cells (pDCs) infiltrate sites of acute Th2-dominant inflammation, but their role in allergic asthma remains unclear.

OBJECTIVE

To characterize circulating pDCs from patients with allergic asthma outside their respective allergen season.

METHODS

Adhesion molecules, co-stimulatory molecules, immunoglobulin receptors and chemokine receptors were quantified on blood pDCs from 20 patients with allergic asthma and 18 healthy controls using flow cytometry. In addition, IL-6-, TNF-α- and IFN-α-secretion were analysed after stimulating isolated pDCs with TLR7- and TLR9-ligands.

RESULTS

Plasmacytoid dendritic cells from patients with allergic asthma showed an increased expression of chemokine receptors involved in inflamed tissue homing such as CCR2, CCR4, CCR9, CCR10, CXCR2, CXCR5 and CXCR6, while the expression of the lymph node homing receptor CXCR3 was down-regulated. In addition, these pDCs exhibited a higher expression of activation markers and Th2-associated molecules such as CD40, CD62L, CD64 and FcεRIα. In contrast, TLR7-mediated IL-6-, TNF-α- and IFN-α-secretion was significantly reduced in pDCs from patients with asthma. The TLR9-mediated cytokine response was only suppressed in those patients who were treated with inhaled corticosteroids (ICS) during previous allergen seasons. The same effect was observed for CD54 and OX40L expression.

CONCLUSIONS

We report an increased expression of activation markers, and Th2-associated molecules, and an increased migratory potential of circulating pDCs in allergic asthma. These changes are accompanied by a reduced TLR7-mediated cytokine response. In addition, our results suggest a longterm impact of ICS treatment on the characteristics of circulating pDCs.

E- and P-selectins are essential for the development of cockroach allergen-induced airway responses

Peribronchial inflammation contributes to the pathophysiology of allergic asthma. In many vascular beds, adhesive interactions between leukocytes and the endothelial surface initiate the recruitment of circulating cells. Previous studies using OVA-induced airway hyperreactivity indicated that P-selectin, a member of the selectin family expressed by activated platelets and endothelium, contributed to both inflammation and bronchoconstriction. The current study used cockroach allergen (CRA), an allergen that induces asthmatic responses in both humans and mice, to further investigate the role of selectins in the development of peribronchial inflammation and airway hyperreactivity. P- and E-selectin mRNAs were detected in extracts of CRA-sensitized animals beginning shortly after intratracheal challenge with CRA. The P-selectin mRNA was transiently induced at early time points while up-regulation of the E-selectin mRNA was more prolonged. Mice with targeted deletions in E-selectin (E(-)), P-selectin (P(-)), and both genes (E(-)/P(-)) showed 70-85% reductions in airway hyperreactivity, peribronchial inflammation, and eosinophil accumulation. The P(-) and E(-)/P(-) groups showed the most profound reductions. The transfer of splenic lymphocytes from CRA-primed E(-)/P(-) into naive wild-type (WT) mice produced the same level of airway hyperreactivity as transfers from CRA-primed WT into naive WT hosts, indicating that peripheral immunization was similar. The observed changes in the selectin-deficient animals were not related to inadequate sensitization, because CRA priming and challenge increased serum IgE levels. Furthermore, pulmonary Th2-type cytokines and chemokines in the E-selectin(-/-) and WT animals were similar. The findings indicate that both P- and E-selectin contribute to CRA-induced peribronchial inflammation and airway hyperreactivity.

Additive anti-inflammatory effect of formoterol and budesonide on human lung fibroblasts

BACKGROUND

It has been shown that treatment with a long acting beta2 agonist in addition to a glucocorticoid is beneficial in the treatment of asthma. In asthma inflammatory cells, particularly eosinophils, migrate into the pulmonary tissue and airway lumen by means of adhesion molecules expressed on resident tissue cells--that is, fibroblasts--and become activated by cytokines and adhesive interactions. A study was undertaken to determine whether an interaction exists between the long acting beta2 agonist formoterol and the glucocorticoid budesonide on inhibition of adhesion molecule expression, as well as chemo/cytokine production by human lung fibroblasts.

METHODS

Lung fibroblasts were preincubated with therapeutically relevant drug concentrations of 10(-8) M to 10(-10) M. Cells were stimulated with interleukin (IL)-1beta (1 or 10 U/ml) for 8 hours and supernatants were collected for measurement of GM-CSF and IL-8 concentrations. The cells were fixed and subjected to a cell surface ELISA technique to measure the expression of ICAM-1 and VCAM-1.

RESULTS

Formoterol exerted an additive effect on the inhibition of IL-1beta stimulated ICAM-1 and VCAM-1 upregulation and GM-CSF production by budesonide in concentrations of 10(-9) M and above (p<0.05). IL-8 production was not influenced by formoterol.

CONCLUSION

Formoterol exerts an additive effect on the anti-inflammatory properties of budesonide. In vitro data support the finding that the combination of budesonide and formoterol in asthma treatment strengthens the beneficial effect of either drug alone.

Experimental rhinovirus 16 infection increases intercellular adhesion molecule-1 expression in bronchial epithelium of asthmatics regardless of inhaled steroid treatment

BACKGROUND

Rhinovirus infections in airway epithelial cells in vitro have been shown to upregulate intercellular adhesion molecule-1 (ICAM-1) expression. Epithelial ICAM-1, in its dual role as the major rhinovirus receptor and as adhesion molecule for inflammatory cells may be involved in the pathogenesis of rhinovirus-induced exacerbations of asthma.

OBJECTIVE

We aimed to investigate the effect of experimental rhinovirus 16 (RV16) infection on ICAM-1 expression in bronchial mucosal biopsies in asthma. In addition, the effect of 2 weeks pretreatment with inhaled budesonide (800 microg b.d.) on RV16-associated changes in ICAM-1 expression was studied.

METHODS

The study had a parallel, placebo-controlled design in 25 steroid-naive nonsmoking atopic asthmatic subjects. After 2 weeks budesonide (BUD) or placebo (PLAC) pretreatment bronchoscopy was performed 2 days before (day -2) and 6 days after (day 6) RV16 inoculation (on days 0 and 1). Immunohistochemical staining for ICAM-1 was performed on snap-frozen bronchial biopsies. ICAM-1 staining intensity on the basal epithelial cells was scored semiquantitatively from 1 (weak) to 3 (intense). Similarly, epithelial intactness was noted (1 = basal cells only, 2 = basal and parabasal cells, 3 = intact epithelium).

RESULTS

ICAM-1 scores were not significantly different between the groups at day -2 (P > or = 0.08). Subsequent RV16 infection was associated with a trend towards an increase in ICAM-1 expression in the BUD-group (P = 0.07), whereas the increase was significant in the PLAC-group (P = 0.03). However, the increase was not significantly different between the groups (P = 0.74). Epithelial intactness score was not different between the groups before RV16 infection (P > or = 0.07), and no significant changes were observed in either group (P > or = 0.59). Moreover, ICAM-1 score did not correlate significantly with epithelium score in either group, at any time-point (P > or = 0.27).

CONCLUSION

We conclude that an RV16 common cold in atopic asthmatic subjects is associated with increased ICAM-1 expression in the bronchial epithelium, which is not related to epithelial intactness. Glucocorticoid treatment does not appear to prevent the RV16-associated increased ICAM-1 expression. This suggests that other treatment modalities are required to protect against the spreading of infection during rhinovirus-induced exacerbations in asthma.

Regulation of ICAM-3 and other adhesion molecule expressions on eosinophils in vitro. Effects of dexamethasone

BACKGROUND

ICAM-3 has been recently identified as the third leukocyte-function associated-1 (LFA-1) ligand. ICAM-3 is expressed in eosinophils, but its regulation has not been studied. The objective of this study was to investigate the differential expression of ICAM-3 and other adhesion molecules (AM) on the surface of eosinophils. We also evaluated the effects of dexamethasone on AM expression.

METHODS

Normodense eosinophils were isolated from peripheral blood and incubated with calcium ionophore A23187 (calcimycin) with and without dexamethasone. Expression of AM was assessed by flow cytometry and expressed as fluorescence mean intensity (FMI).

RESULTS

Peripheral blood eosinophils constitutively expressed low levels of ICAM-1 and ICAM-2 (<10 FMI), moderate levels (10-50 FMI) of CD29 and L-selectin, and high levels (>50 FMI) of ICAM-3, LFA-1, and Mac-1. Calcium ionophore (1 microM) significantly increased Mac-1 and ICAM-1 expression at 6 and 24 h. L-selectin expression decreased at 6 and 24 h, but ICAM-2, ICAM-3, LFA-1, and CD29 expression did not show any significant change after calcium ionophore stimulation. Dexamethasone decreased ICAM-3 and increased L-selectin basal expression, and it caused a dose-related inhibition of calcium ionophore-induced ICAM-1 expression.

CONCLUSIONS

These findings suggest that some AM, such as ICAM-1, Mac-1, and L-selectin, may be involved in adhesion during eosinophil activation and that glucocorticoids may prevent airway inflammation by regulating the expression of AM in eosinophils. The role of ICAM-3, a leukocyte AM highly expressed in resting eosinophils, remains to be clarified.

Glucocorticoids: mechanisms of action and anti-inflammatory potential in asthma

GLUCOCORTICOIDS are potent inhibitors of inflammatory processes and are widely used in the treatment of asthma. The anti-inflammatory effects are mediated either by direct binding of the glucocorticoid/glucocorticoid receptor complex to glucocorticoid responsive elements in the promoter region of genes, or by an interaction of this complex with other transcription factors, in particular activating protein-1 or nuclear factor-kappaB. Glucocorticoids inhibit many inflammation-associated molecules such as cytokines, chemokines, arachidonic acid metabolites, and adhesion molecules. In contrast, anti-inflammatory mediators often are up-regulated by glucocorticoids. In vivo studies have shown that treatment of asthmatic patients with inhaled glucocorticoids inhibits the bronchial inflammation and simultaneously improves their lung function. In this review, our current knowledge of the mechanism of action of glucocorticoids and their anti-inflammatory potential in asthma is described. Since bronchial epithelial cells may be important targets for glucocorticoid therapy in asthma, the effects of glucocorticoids on epithelial expressed inflammatory genes will be emphasized.