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Interactions between Corticosteroids and ß₂-Agonists in Asthma and Chronic Obstructive Pulmonary Disease

GlaxoSmithKline Research and Development, Middlesex, United Kingdom

Correspondence and requests for reprints should be addressed to Malcolm Johnson, Ph.D., GlaxoSmithKline Research & Development, Greenford Road, Middlesex UB6 OHE, UK. Email: malcolm.w.johnson{at}gsk.com

	ABSTRACT

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The combination of a long-acting ß₂-agonist (LABA) and an inhaled corticosteroid is more efficacious in asthma and chronic obstructive pulmonary disease (COPD) than other combination therapies or than either alone. Corticosteroids may regulate ß₂-receptor function by increasing expression of the receptor, restoring G-protein/ß₂-receptor coupling, and inhibiting ß₂-receptor downregulation. LABAs may prime the glucocorticoid receptor and affect its nuclear localization by modulating glucocorticoid receptor phosphorylation. These mechanisms suggest the possibility of interactions between the two classes of drugs at the molecular and receptor levels. Indeed, there is evidence that corticosteroid/ß₂-agonist combination therapy has complementary, additive, and synergistic inhibitory effects on proinflammatory signaling pathways, inflammatory mediator release, and recruitment and survival of inflammatory cells. In the asthmatic patient, this is reflected in enhanced anti-inflammatory activity with combination therapy beyond that which can be achieved by either drug alone, or the potential for LABAs to provide a steroid-sparing effect. Corticosteroid/ß₂-agonist combined activity may also overcome the reduced sensitivity to inhaled corticosteroids that has been reported in some patients with COPD.

Key Words: combination therapy • inhaled corticosteroids • long-acting ß₂-agonists • mechanisms

The underlying pathophysiology of bronchial asthma and chronic obstructive pulmonary disease (COPD) is complex and multifactorial.

Bronchial asthma is characterized by smooth-muscle dysfunction, airway inflammation, and airway remodeling (1). Smooth-muscle dysfunction is evidenced by exaggerated bronchoconstriction, bronchial hyperresponsiveness, hyperplasia, and possibly hypertrophy of the airway smooth-muscle cells and their release of proinflammatory mediators.

In asthma, acute and chronic airway inflammation (1) is the result of the recruitment and activation of a range of inflammatory cells, including mast cells, eosinophils, and CD4⁺ T lymphocytes, and the release of mediators that perpetuate the inflammatory cycle, causing edema formation and epithelial damage. The remodeling process induces permanent changes to the airway structure, such as the proliferation of resident cells and thickening of the reticular layer of the basement membrane (1). COPD is a heterogeneous group of disorders involving the large airways, small airways, and lung parenchyma (2), consisting of airway inflammation, structural changes, mucociliary dysfunction, and a systemic component, all of which contribute to the airflow limitation characteristic of the disease. There are increased numbers of inflammatory cells, such as CD8⁺ T lymphocytes, monocytes/macrophages, and neutrophils, and elevated levels of inflammatory mediators, such as interleukin (IL)-8, tumor necrosis factor (TNF)-, leukotriene B₄, and in exacerbations the chemokine, regulated upon activation, normal T-cell expressed and secreted (RANTES). Inflammation in COPD is associated with many structural changes, such as goblet cell hyperplasia and submucosal glandular hypertrophy in the large airways, fibrosis with collagen deposition and thickening of airway smooth muscle in the small airways, and alveolar destruction in the parenchyma (2). Patients with COPD exhibit ciliary abnormalities, mucus hypersecretion, increased mucus viscosity, and reduced mucociliary transport, all of which promote bacterial colonization and mucosal damage (2).

A number of clinical studies (3–6) have shown that patients with asthma and patients with COPD treated with long-acting ß₂-agonists (LABAs) and inhaled corticosteroids (ICSs) have better lung function, increased symptom control, and reduced exacerbations compared with those given either LABAs or higher doses of ICS alone. In asthma, ICSs inhibit many aspects of chronic inflammation and may resolve some of the processes of airway remodeling, whereas LABAs have long-lasting effects on airway smooth muscle and attenuate components of acute inflammation (7). In COPD, ICSs have been shown to affect key inflammatory cells and mediators, and LABAs have additional effects on mucociliary dysfunction and may influence elements of the systemic component of the disease (8). Furthermore, the combination of a LABA and an ICS provides greater clinical efficacy in both diseases than other combination therapies, suggesting the possibility of complementary interactions between LABAs and corticosteroids at the molecular and receptor levels.

	MECHANISM OF ACTION OF CORTICOSTEROIDS

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The target receptor for corticosteroids is the intracellular glucocorticoid receptor (GR). Under resting conditions, the inactive GR is largely located in the cytosol of the cell, associated with multiple chaperone proteins. The glucocorticoid molecule first penetrates the cell membrane, then binds to the GR through the glucocorticoid-binding domain (9). This induces a conformational change in the receptor protein, dissociation of the chaperone proteins, and the formation of an active glucocorticoid–GR complex. The complex may then form a dimer and translocate from the cytosol to the nucleus of the cell, where it binds to specific DNA sequences (glucocorticoid response elements, GREs) in the promoter region of target genes, leading to cofactor activation and either an increase or decrease in gene transcription. This process is termed transactivation (9).

Alternatively, the active glucocorticoid–GR complex, as a monomer, can interact directly with intracellular transcription factors such as activator protein-1 (AP-1) or nuclear factor (NF)-B, through a protein–protein interaction, to attenuate the proinflammatory processes mediated by those transcription factors. This process, termed transrepression, involves recruitment of histone deacetylases and modulation of chromatin structure (10).

	MECHANISM OF ACTION OF ß2-AGONISTS

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All ß₂-agonists exert their biological and therapeutic effects through cell-surface ß₂-adrenoceptors, which are members of the 7-transmembrane, G-protein–coupled receptor family. After ligand binding to the active site of the receptor, the -component of the associated G_s-protein dissociates and activates adenylate cyclase. This process leads to the production of intracellular cyclic adenosine monophosphate (cAMP) and subsequent activation of protein kinase A (PKA), which then phosphorylates a number of intracellular regulatory proteins (11).

ß₂-Agonists may also influence gene transcription, through a cAMP mechanism, whereby there is increased translocation of the catalytic subunit of PKA to the nucleus and phosphorylation of CREB-binding protein, enhancing its DNA-binding and transactivation effects (12, 13). Recently, it has been reported that activation of the ß₂-receptor can also lead to coupling to G_i, resulting in stimulation of the extracellular signal-regulated kinase pathway and the p38 mitogen-activated protein kinase (MAPK) pathway (14).

The mechanisms of action of the LABAs, salmeterol and formoterol, have been reported previously (14–16). Briefly, salmeterol partitions into the cell membrane and diffuses laterally to the ß₂-receptor. The side chain of the molecule then binds to a discrete, hydrophobic region of the fourth transmembrane domain, the exo-site. Binding to the exo-site prevents salmeterol from dissociating from the receptor, while the saligenin head of the molecule is free to engage and disengage the active site by a Charnière (hinge) principle, leading to a long, concentration-independent duration of action (14). Formoterol, which is moderately lipophilic, is taken up into the cell membrane as a depot. The drug then progressively leaches out to activate the ß₂-receptor, imparting a prolonged, concentration-dependent action (16).

	INTERACTIONS BETWEEN CORTICOSTEROIDS AND LABAs

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In discussing possible interactions between corticosteroids and LABAs, it is important to make clear distinctions between three similar terms. A complementary effect occurs when the response to two or more drugs combined is greater than the response to either drug alone. An additive effect occurs when the response of two or more drugs combined equals the sum of the responses to the individual drugs. A synergistic effect occurs when the response to two or more drugs combined is greater than the sum of the responses to the individual drugs.

Effects of Corticosteroids on ß₂-Receptors
Corticosteroids can modulate ß₂-receptors and their function by several mechanisms: protection against desensitization and the development of tolerance, increased efficiency of receptor coupling, and protection against inflammation-induced receptor downregulation and uncoupling. Corticosteroids stimulate the transcription of ß₂-receptors via binding to GREs in the 5'-noncoding promoter region of the ß₂-receptor gene (Figure 1). Dexamethasone has been shown to increase ß₂-receptor mRNA and protein in human lung tissue in vitro (17). This increase in transcription, which has also been shown in neutrophils and T cells, is both time- and dose-dependent, consistent with the later induction of receptor-binding activity. However, dexamethasone has not been found to alter the half-life of ß₂-receptor mRNA (17). Baraniuk and colleagues (18) reported that intranasal administration of beclomethasone dipropionate (100 µg/day x 3 days) significantly increased the density of ß₂-receptors on the nasal mucosa. Both systemic corticosteroids and ICSs reversed ß₂-receptor downregulation after exposure to high doses of short-acting ß₂-agonists (19).

View larger version (75K): [in this window] [in a new window]   Figure 1. Synergistic interactions between long-acting ß2-agonists (LABA; salmeterol) and corticosteroids (fluticasone). Corticosteroids penetrate the cell membrane and bind to inactive glucocorticoid receptor (GR), forming an active receptor complex. This complex translocates to the nucleus and activates target genes such as the ß2-adrenoceptor gene. ß2-Receptor protein is synthesized and inserted into the cell membrane. LABAs, through the ß2-receptor, stimulate an intracellular biochemical cascade, leading to priming of the GR. The primed GR requires less corticosteroids to form an active receptor complex. These interacting pathways provide a molecular basis for positive interactions between LABAs and corticosteroids.

Another study (21) has shown that proinflammatory cytokines such as IL-1ß and transforming growth factor (TGF)-ß₁ regulate the coupling of ß₂-receptors to adenylate cyclase and receptor sensitivity. Corticosteroids, by reducing the concentration of such cytokines, may prevent or reverse these effects. This may have clinical relevance in preventing the development of tolerance to ß₂-agonists in patients with asthma and patients with COPD on chronic therapy.

Effects of LABAs on the GR
LABAs prime the GR for subsequent corticosteroid binding by mitogen-activated protein kinase (MAPK)-dependent phosphorylation (22). After stimulation of the ß₂-receptor by salmeterol and dissociation of the -component of G_s, the residual ß-subunit of the G-protein initiates an intracellular signaling cascade involving the nonreceptor tyrosine kinase C-Src and the G-protein Ras, culminating in the stimulation of MAPK (23). This has been demonstrated in human embryonic kidney cells transfected with a MAPK–luciferin/luciferase reporter construct, as well as by isolation of phospho-MAPK (24). The identity of the MAPK activated by salmeterol is unclear.

Activation of the MAPK pathway by the LABA requires that the ß₂-receptor be phosphorylated, probably by PKA. MAPK then phosphorylates the GR at a number of proline-directed serine residues in the N-terminus region of the receptor. Indeed, phospho-GR has been detected in cells containing both ß₂-receptors and GR, when stimulated with salmeterol (25). It is possible that an increase in negative charge at the N-terminal domain of the receptor leads to a conformational change in the GR protein, leading in turn to the "priming" event and rendering the receptor more sensitive to steroid-dependent activation (Figure 1).

Other studies have shown that translocation of the GR from the cell cytosol to the nucleus, a fundamental step in the anti-inflammatory activity of corticosteroids, is increased by the addition of a LABA (26, 27). Eickelberg and colleagues (26) showed that treatment of human lung fibroblasts and smooth muscle cells with fluticasone and salmeterol resulted in increased translocation compared with fluticasone treatment alone. Electrophoretic mobility shift assays confirmed that the LABA-activated nuclear GR actively bound to the GRE consensus sequence. The effects of salmeterol were mediated by the ß₂-receptor and by PKA, as receptor blockade with propranolol or the use of a PKA-inhibitor peptide abrogated GR activation (26).

These in vitro findings have now been confirmed in vivo in patients with asthma treated with LABA and corticosteroids. Usmani and colleagues (27) showed that inhalation of salmeterol (50 µg) and fluticasone (100 µg) increased the nuclear translocation of the GR in sputum macrophages significantly more than the same dose of fluticasone alone. The results were equivalent to those observed with a fivefold higher dose of the steroid. Whether these effects of salmeterol can be shown in the patient with COPD remains to be determined. In contrast, whereas budesonide (800 µg) also significantly increased the translocation of the GR from the cytosol into the nuclei of peripheral blood leukocytes, combination with formoterol (24 µg) did not enhance this effect versus budesonide alone (28).

The interactions between corticosteroids and LABAs may, therefore, be summarized as follows: corticosteroids increase ß₂-receptor synthesis, and LABAs prime the GR for steroid-dependent activation. These mechanisms form a possible molecular and receptor basis for additive and synergistic interactions between the two classes of drugs in the treatment of asthma and COPD.

Effects of Corticosteroid/LABA on Proinflammatory Signaling Pathways
Airway inflammation is an important component of the pathophysiology of both asthma and COPD (1, 2). Proinflammatory transcription factors such as NF-B and AP-1 are key to the signaling pathways involved. NF-B is retained in the cytoplasm by the inhibitory protein IB, but when this is phosphorylated by the IB kinase, IKK-2, NF-B is released for transport to the nucleus, where it promotes the transcription of proinflammatory genes (29).

TNF- induction of a NF-B reporter gene in airway epithelial cells is inhibited by fluticasone, and this inhibition is enhanced in the presence of salmeterol (30). The mechanism of this effect may be mediated through reduced IB phosphorylation. Fluticasone administration (10^–8 to 10^–7 M) resulted in a concentration-dependent decrease in phospho-IB in T cells. Salmeterol (10^–8 M) was without effect, but it increased the suppressive effect of fluticasone so that the combined effect was greater than that obtained with a 10-fold higher concentration of fluticasone alone, thus providing evidence for synergy at the molecular level (31). In vivo studies (32) have suggested that a LABA and a corticosteroid can also interact to enhance the nuclear export of the transcription factor, GATA-3. Nuclear GATA-3 expression was reduced in mononuclear cells 60 minutes after patients inhaled 500 µg of fluticasone but not after administration of 100 µg. However, in the presence of salmeterol (50 µg), the effect of 100 µg of fluticasone was significantly enhanced, and there was no difference between the effects of the two doses of fluticasone (32).

Effects of Corticosteroid/LABA on Inflammatory Mediator Release
In sputum and bronchoalveolar lavage fluid, elevated levels of inflammatory mediators, such as IL-4, IL-5, IL-10, IL-13, and granulocyte macrophage colony-stimulating factor (GM-CSF), have been detected in asthma; elevated levels of TNF-, IL-8, leukotriene B₄, and RANTES have been detected in COPD in exacerbations (1, 2). The interactions between a corticosteroid and a LABA result in complementary inhibitory effects on cytokine and chemokine release. For example, human airway epithelial cells stimulated with TNF- release GM-CSF. This release is partially inhibited by budesonide and also by formoterol (Figure 2). However, when budesonide and formoterol are combined, the level of cytokine inhibition is increased in an additive manner (33). The combination of fluticasone (10^–9 M) and salmeterol (10^–9 M) synergistically inhibit rhinovirus-induced IL-8 and RANTES release (34) from bronchial epithelial cells (Figure 3). Such an effect may be of relevance to the efficacy of combination therapy in reducing COPD exacerbations.

View larger version (123K): [in this window] [in a new window]   Figure 2. Additive inhibitory effect of budesonide and formoterol on granulocyte–macrophage colony-stimulating factor (GM-CSF) release from human airway epithelial cells. Tumor necrosis factor- (TNF-)–induced GM-CSF release was measured in the presence of budesonide (B, 10–8 M), formoterol (F, 10–10 M), and the combination. BL indicates baseline. Adapted by permission from Ref. 33.

View larger version (149K): [in this window] [in a new window]   Figure 3. Synergistic inhibitory effect of fluticasone plus salmeterol on regulated on activation, normal T cell expressed and secreted (RANTES) release from human airway epithelial cells. Human rhinovirus–induced RANTES release was measured in the presence of fluticasone propionate (FP, 10–9 and 10–8 M) and the combination of FP (10–9 M) and salmeterol (SM, 10–9 M). *p < .05. **p < .01. Adapted by permission from Ref. 34.

View larger version (136K): [in this window] [in a new window]   Figure 4. Synergistic inhibitory effect of fluticasone plus salmeterol on interleukin-8 (IL-8) release from human airway smooth-muscle cells. TNF-–induced release of IL-8 was measured in the presence of fluticasone propionate (FP, 10–8 M), salmeterol (SALM, 10–7 M), and the combination. Adapted by permission from Ref. 36.

Elevated numbers of eosinophils have been found in induced sputum, bronchial biopsies, and the lamina propria of individuals with asthma and patients with COPD, particularly during exacerbations. Both formoterol (1 to 10 nM) and budesonide (1 to 100 nM) inhibited superoxide generation from peripheral blood eosinophils (40). Even though a low concentration of budesonide (0.1 nM) had little inhibitory effect alone, the combination of budesonide and formoterol (1 nM) inhibited eosinophilic oxidative burst to a level that exceeded an additive effect (40).

Effects of Corticosteroid/LABA on Inflammatory Cells
In vitro studies.
A key element in the anti-inflammatory effects of corticosteroids in asthma is their ability to inhibit the recruitment of inflammatory cells and shorten their survival in airway tissue. Fluticasone inhibits eosinophil adhesion to intercellular cell-adhesion molecule-1, an important step in cell infiltration, recruitment and tissue retention and this inhibition is synergistically increased in the presence of salmeterol (41). Similarly, fluticasone produces a concentration-dependent increase in apoptosis in eosinophils obtained by bronchoalveolar lavage fluid from individuals with asthma (42). Salmeterol alone has little effect but increases the potency of fluticasone by approximately threefold. The addition of salmeterol enhances apoptosis of T-lymphocytes in response to fluticasone, at both low and higher concentrations, and this increase is associated with greater GR nuclear translocation (43).

The epithelium may be an additional target for the interaction between LABAs and corticosteroids in COPD. Dowling and colleagues (44) reported that incubation of human respiratory mucosa with fluticasone or salmeterol significantly inhibited Pseudomonas aeruginosa–induced epithelial damage and loss of ciliated cells in a concentration-dependent manner. However, when a combination of fluticasone and salmeterol was used, the loss of cilia from the epithelial surface was significantly reduced compared with the results obtained after treatment with fluticasone or salmeterol alone (44).

Fibrotic changes in the airway in asthma and COPD have been shown to be associated with increased numbers of activated fibroblasts, many of which have the phenotypic characteristics of myofibroblasts (e.g., they express -smooth muscle actin, -SMA).

Giuliani and coworkers (45) showed that TGF-ß₁, a cytokine present in increased quantities in COPD, induced a dose-dependent increase in the number of SMA(+) cells in primary human airway fibroblast culture. This TGF-ß₁–induced myofibroblast differentiation was effectively downregulated by fluticasone and salmeterol. When the two agents were administered together, they produced an inhibitory effect significantly greater than that produced by either agent alone (45).

In vivo studies.
Two studies have examined the possibility of complementary interactions between LABAs and corticosteroids on airway inflammation in patients with asthma.

In patients previously treated with ICSs, the addition of salmeterol (50 µg twice daily) for 12 weeks led to a reduction in the total number of activated eosinophils in the lamina propria (46). Sue-Chu and associates (47) evaluated treatment with fluticasone (200 µg twice daily), fluticasone (200 µg twice daily) plus salmeterol (50 µg twice daily), or higher-dose fluticasone (500 µg twice daily) for 3 months in patients previously uncontrolled on an ICS. Analysis of biopsy tissue obtained before and after treatment indicated ongoing inflammation, with an increase in mast cells, CD3(+) cells, and CD4(+) cells, in the low-dose fluticasone group. These increases were not observed in either the group receiving combination therapy or in the higher-dose fluticasone group. Changes in airway inflammation were associated with a significant reduction in symptoms of clinical disease (47).

Bronchial hyperreactivity is considered a clinical surrogate for airway inflammation in asthma. Swenson and colleagues (48) investigated the effect of fluticasone/salmeterol (100/50 µg twice daily) combination therapy on antigen-induced bronchial hyperresponsiveness to methacholine in mild asthmatics. After 28 days, there was a significantly greater level of bronchoprotection (approximately 2.5 doubling dilutions) compared with the same doses of fluticasone and salmeterol administered alone (48). Similar evidence of the synergy of these drugs was observed in a 1-year study of fluticasone (500 µg twice daily), salmeterol (50 µg twice daily), or the combination in COPD patients (5). By Week 52, pre-dose FEV₁ in the patients with more severe disease (FEV₁ < 50% predicted) receiving combination therapy had increased by 110 L compared with 20 L in the salmeterol group and 40 L in the fluticasone group (p < 0.0001 versus placebo, salmeterol, FP). The median percentage of days without reliever medication was 0% for placebo, 3% for salmeterol, 2% for fluticasone, and 14% for combination therapy (p < 0.004).

Airway remodeling occurs in both asthma and COPD. There is evidence of increased airway vascularity (angiogenesis) despite the use of ICSs. Orsida and colleagues (49) investigated the effect of adding salmeterol (50 µg twice daily) to an ICS regimen, compared with increasing the steroid dose, on the degree of submucosal angiogenesis as assessed by immunohistochemistry for collagen IV. There was a significant reduction in vascularity in the salmeterol/ICS group during the 3 months of treatment, whereas no effect was observed after high-dose ICS treatment (Figure 5). This raises the possibility that combination therapy with a corticosteroid and a LABA may be able to alleviate some components of airway remodeling in asthma and COPD.

View larger version (118K): [in this window] [in a new window]   Figure 5. Synergistic effect of corticosteroid/LABA therapy on airway angiogenesis in asthma. In patients with asthma, being treated with an ICS, the effect of adding additional steroid (fluticasone propionate [FP] 100 µg BID) or salmeterol (50 µg BID) on angiogenesis (subepithelial vascularity as assessed by collagen IV staining) was assessed over 3 months. *p = 0.004. **p = 0.04. Adapted by permission from Ref. 49.

	CONCLUSIONS

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	ACKNOWLEDGMENTS

 
M.J. is employed by GlaxoSmithKline, who supported the meeting on which the manuscript is based through an educational grant and has an interest in the subject matter detailed in the manuscript, and he owns in stock in GSK.

(Received in original form February 18, 2004; accepted in final form April 13, 2004)

	REFERENCES

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1. Bousquet J, Jeffery PK, Busse WW, Johnson M, Vignola AM. Asthma: from bronchoconstriction to airways inflammation and remodelling. Am J Respir Crit Care Med 2000;161:1720–1745.[Free Full Text]
2. Jeffery PK. Differences and similarities between chronic obstructive pulmonary disease and asthma. Clin Exp Allergy 1999;29:14–26.
3. Woodcock A, Lundback B, Ringdal N, Jacques LA. Comparison of addition of salmeterol to inhaled steroids with doubling of the dose of inhaled steroids. Am J Respir Crit Care Med 1996;153:1481–1488.[Abstract]
4. Condemi JJ, Goldstein S, Kalberg C, Yancey S, Emmett A, Rickard KA, and the Salmeterol Study Group. The addition of salmeterol to fluticasone propionate versus increasing the dose of fluticasone propionate in patients with persistent asthma. Ann Allergy Asthma Immunol 1999;82:383–389.[Medline]
5. Calverley P, Paulwels R, Vestbo J, Jones P, Pride N, Gulsvik A, Anderson G, Maden C, the TRISTAN (Trial of Inhaled Steroids and long-acting ß₂ agonists) study group. Combined salmeterol and fluticasone in the treatment of chronic obstructive pulmonary disease: a randomised controlled trial. Lancet 2003;361:449–456.[CrossRef][Medline]
6. Szafranski W, Cukier A, Ramirez A, Menga G, Sansores R, Nahabedian S, Peterson S, Olsson H. Efficacy and safety of budesonide/formoterol in the management of chronic obstructive pulmonary disease. Eur Respir J 2003;21:74–81.[Abstract/Free Full Text]
7. Johnson M. Combination therapy for asthma: complementary effects of long-acting ß₂-agonists and corticosteroids. Curr Allergy Clin Immunol 2002;15:16–22.
8. Johnson M, Rodriguez-Roisin R, Vignola M. Multicomponent pathophysiology of COPD: a basis for combination therapy. Eur Respir J (In press)
9. Barnes PJ. Molecular mechanisms of steroid action in asthma. J Allergy Clin Immunol 1997;1:159–168.
10. Adcock IM, Ito K. Molecular mechanisms of corticosteroid actions. Monaldi Arch Chest Dis 2000;55:256–266.[Medline]
11. Johnson M. The ß₂-adrenoceptor. Am J Respir Crit Care Med 1998;158:S146–S153.[Abstract/Free Full Text]
12. Montminy MR, Gonzalez GA, Yamamoto KK. Regulation of cAMP-inducible genes by CREB. Trends Neurosci 1990;13:184–188.[CrossRef][Medline]
13. Nishikawa M, Mak JCW, Shirasaki H, Barnes PJ. Differential down-regulation of pulmonary ß₁ and ß₂-adrenoceptor messenger RNA with prolonged in vivo infusion of isoprenaline. Eur J Pharmacol 1993;247:131–138.[CrossRef][Medline]
14. Johnson M. Mechanisms of action of ß₂-adrenoceptor agonists. In: Busse WW, Holgate ST, editors. Asthma and rhinitis. Oxford: Blackwell; 2000. p. 1541–1557.
15. Collins S, Altschmied J, Herbsman O, Caron MG, Mellon PL, Lefkowitz RJ. A cAMP response element in the ß₂-adrenergic receptor gene confers transcriptional autoregulation by cAMP. J Biol Chem 1990;265:19330–19335.[Abstract/Free Full Text]
16. Anderson GP. Formoterol: pharmacology, molecular basis of agonism, and mechanism of long duration of a highly potent and selective ß₂-adrenoceptor agonist bronchodilator. Life Sci 1993;52:2145–2160.[CrossRef][Medline]
17. Mak JCW, Nishikawa M, Barnes PJ. Glucocorticosteroids increase ß₂-adrenergic receptor transcription in human lung. Am J Physiol 1995;268:L41–L46.
18. Baraniuk JN, Ali M, Brody D, Maniscalco J, Gaumond E, Fitzgerald T, Wong G, Yuta A, Mak JCW, Barnes PJ. Glucocorticoids induce ß₂-adrenergic receptor function in human nasal mucosa. Am J Respir Crit Care Med 1997;155:704–710.[Abstract]
19. Hadcock JR, Wang H-Y, Malbon CC. Agonist-induced destabilization of ß-adrenergic receptor mRNA: attenuation of glucocorticoid-induced up-regulation of ß-adrenergic receptors. J Biol Chem 1989;264:19928–19933.[Abstract/Free Full Text]
20. Mak JCW, Nishikawa M, Shirasaki H, Miyayasu K, Barnes PJ. Protective effects of a glucocorticoid on downregulation of pulmonary ß₂-adrenergic receptors in vivo. J Clin Invest 1995;96:99–106.
21. Koto HM, Mak JCW, Haddad E-B, Xu WB, Salmon M, Barnes PJ, Chung KF. Mechanisms of impaired ß-adrenoceptor-induced airway relaxation by interleukin-1ß in vivo in the rat. J Clin Invest 1996;98:1780–1787.[Medline]
22. Adcock IM, Maneechotesuwan K, Usmani O. Molecular interactions between glucocorticoids and long-acting ß₂-agonists. J Allergy Clin Immunol 2002;110:S261–S268.[CrossRef][Medline]
23. Daaka Y, Luttrell LM, Lefkowitz RJ. Switching of the coupling of the ß₂-adrenergic receptor to different G proteins by protein kinase A. Nature 1997;390:88–91.[CrossRef][Medline]
24. Latif ML, Hill SJ. Salmeterol induction of mitogen-activated protein kinase (MAPK) in transfected HEK cells. Br J Pharmacol 1998;125:717–726.[CrossRef][Medline]
25. Adcock IM, Maneechotesuwan I, Usmani O. Effects of LABA on GR function: possible role of GR phosphorylation. J Allergy Clin Immunol 2002;110:S261–S268.
26. Eickelberg O, Roth M, Lörx R, Bruce V, Rüdiger J, Johnson M, Block L-H. Ligand-independent activation of the glucocorticoid receptor by the ß₂-adrenergic receptor agonists in primary human lung fibroblasts and vascular smooth muscle cells. J Biol Chem 1999;274:1005–1010.[Abstract/Free Full Text]
27. Usmani OS, Maneechotesuwan K, Adcock IM, Barnes PJ. Glucocorticoid receptor activation following inhaled fluticasone and salmeterol [abstract]. Am J Respir Crit Care Med 2002;165:A616.
28. Leufgen H, Rüdiger J, Herrmann MJ, Meyer L, Solér M, Perruchoud AP, Tamm M. Glucocorticoid receptor activation by steroids and long-acting beta₂-agonists in vivo: a double blind crossover study [abstract]. Am J Respir Crit Care Med 2002;165:A618.
29. Bennett BL, Manning AM. Activator protein-1 and nuclear factor-B. In: Hansel TT, Barnes PJ, editors. New drugs for asthma, allergy and COPD. Progress in Respiratory Research, Vol. 31, Bollinger, CT, editor. Basil, Switzerland: Karger; 2001. p. 337–341.
30. Evans M, Bloom JW. Salmeterol increases fluticasone propionate-induced suppression of NFB-mediated gene transcription in human bronchial epithelial cells. Am J Respir Crit Care Med 2002;163:A576.
31. Gagliardo R, Merendino A, Pompeo F, Siena L, Bellia V, Testi R, Vignola AM. IKKß phosphorylation is modulated by the combination of glucocorticosteroids and long acting ß₂–agonists in human bronchial epithelial cells. Am J Respir Crit Care Med 2003;167:A653.
32. Maneechotesuwan K, Usmani OS, Adcock IM, Barnes PJ. The modulation of GATA-3 nuclear localization by fluticasone and salmeterol [abstract]. Am J Respir Crit Care Med 2002;165:A616.
33. Korn SH, Jerre A, Brattsand R. Additive inhibition of formoterol and budesonide on GM-CSF expression in cultured bronchial epithelial cells [abstract]. Am J Respir Crit Care Med 1999;159:A114.
34. Edwards MR, Johnson M, Johnston SL. Synergistic effects of salmeterol and fluticasone in human rhinovirus induced pro-inflammatory cytokine production [abstract]. Am J Respir Crit Care Med 2003;167:A399.
35. Pang L, Knox AJ. Regulation of TNF--induced eotaxin release from cultured human airway smooth muscle cells by ß₂-agonists and corticosteroids. FASEB J 2001;15:261–269.[Abstract/Free Full Text]
36. Pang L, Knox AJ. Synergistic inhibition by the ß₂-agonists and corticosteroids on Tumor Necrosis Factor--induced interleukin-8 release from cultured human airway smooth-muscle cells. Am J Respir Cell Mol Biol 2000;23:79–85.[Abstract/Free Full Text]
37. Spoelstra FM, Postma DS, Hovenga H, Noordhoek JA, Kauffman HF. Budesonide and formoterol inhibit ICAM-1 and VCAM-1 expression on human lung fibroblasts. Eur Respir J 2000;15:68–74.[Abstract]
38. Karimi G, Folkerts G, Nijkamp FP. Cigarette-smoke induced activation of inflammatory cells: synergistic inhibition by glucocorticosteroids and long-acting ß₂-agonists. Eur Respir J (In press)
39. Seeto LJ, Johnson M, Hendel N, Lim S. Effect of dexamethasone and salmeterol on human alveolar macrophage cytokine production in patients with chronic obstructive pulmonary disease (COPD) [abstract]. Am J Respir Crit Care Med 2002;165:A597.
40. Miller-Larsson A, Persdotter S, Lexmuller K, Lindahl M, Brattsand R. Synergistic inhibition of oxidative burst in human eosinophils by combination treatment with formoterol and budesonide. Eur Respir J 2001;18:48S.
41. Myo S, Zhu X, Myou S, Boetticher E, Meliton AY, Lambertino AT, Munoz NM, Leff AR. Additive inhibition of fluticasone propionate (FP) and salmeterol on ß₂-integrin-mediated adhesion to human eosinophils [abstract]. Am J Respir Crit Care Med 2003;167:A754.
42. Anenden V, Egemba G, Kessel B, Johnson M, Costello J, Kilfeather S. Salmeterol facilitation of fluticasone-induced apoptosis in eosinophils of asthmatics pre and post-antigen challenge [abstract]. Eur Respir J 1998;12:157S.
43. Chiappara G, Merendino AM, Bruno A, Vignola AM, Siena L, Gadliardo R, Bousquet J, Chanez P, Bonsignore G. Evaluation of apoptosis in T-lymphocytes and neutrophils in steroid-dependent asthma [abstract]. Am J Respir Crit Care Med 2001;163:A188.
44. Dowling RB, Johnson M, Cole PJ, Wilson R. Effect of fluticasone propionate (FP) and salmeterol (SM) on P.aeruginosa (PA) infection of respiratory mucosa in vitro [abstract]. Am J Respir Crit Care Med 1998;157:A138.
45. Giuliani M, Serpero L, Petecchia L, Sale R, Sabatini F, Silvestri F, Di Blasi P, Rossi GA. Inhibitory activity of fluticasone propionate and salmeterol on TGF-ß2-induced expression of alpha-smooth muscle actin (alpha-SMA) by human primary airway fibroblasts [abstract]. Am J Respir Crit Care Med 2003;167:A206.
46. Li X, Ward C, Thien F, Bish R, Bamford T, Bao X, Bailey M, Wilson JW, Walters EH. An anti-inflammatory effect of salmeterol, a long-acting ß₂-agonist, assessed in airway biopsies and bronchoalveolar lavage in asthma. Am J Respir Crit Care Med 1999;160:1493–1499.[Abstract/Free Full Text]
47. Sue-Chu M, Wallin A, Wilson S, Ward J, Sandstrom T, Djukanovic R, Holgate ST, Bjermer L. Bronchial biopsy study in asthmatics treated with low and high dose fluticasone propionate compared to low dose FP combined with salmeterol [abstract]. Eur Respir J 1999;14:124S.
48. Swenson C, Laseman J, Busse W. Combination of salmeterol (SAL) and fluticasone (FP) works synergistically to inhibit airway inflammation post allergen challenge. J Allergy Clin Immunol 2003;111:S126.
49. Orsida BE, Ward C, Li X, Bish R, Wilson JW, Thien F. Effect of a long-acting ß₂-agonist over three months on airway wall remodelling in asthma. Am J Respir Crit Care Med 2001;164:117–121.[Abstract/Free Full Text]

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