Synergistic Effects of p38 Mitogen-Activated Protein Kinase Inhibition with a Corticosteroid in Alveolar Macrophages from Patients with Chronic Obstructive Pulmonary Disease

Abstract

Corticosteroids partially suppress cytokine production by chronic obstructive pulmonary disease (COPD) alveolar macrophages. p38 mitogen-activated protein kinase (MAPK) inhibitors are a novel class of anti-inflammatory drug. We have studied the effects of combined treatment with a corticosteroid and a p38 MAPK inhibitor on cytokine production by COPD alveolar macrophages, with the aim of investigating dose-sparing and efficacy-enhancing effects. Alveolar macrophages from 10 patients with COPD, six smokers, and six nonsmokers were stimulated with lipopolysaccharide (LPS) after preincubation with five concentrations of dexamethasone alone, five concentrations of the p38 MAPK inhibitor 1-(5-tert-butyl-2-p-tolyl-2H-pyrazol-3-yl)-3(4-(2-morpholin-4-ylethoxy)naphthalen-1-yl)urea (BIRB-796) alone, and all combinations of these concentrations. After 24 h, the supernatants were analyzed for interleukin (IL)-8, IL-6, tumor necrosis factor ␣ (TNF␣), granulocyte macrophage-colony-stimulating factor (GM-CSF), IL-1␣, IL-1␤, IL-1ra, IL-10, monocyte chemoattractant protein 3, macrophage-derived chemokine (MDC), and regulated on activation normal T cell expressed and secreted (RANTES). The effect of dexamethasone on p38 MAPK activation was analyzed by Western blotting. Dexamethasone and BIRB-796 both reduced LPSinduced cytokine production in a dose-dependent manner in all subject groups, with no differences between groups. Increasing the concentration of BIRB-796 in combination with dexamethasone produced progressively greater inhibition of cytokine production than dexamethasone alone. There were significant efficacyenhancing benefits and synergistic dose-sparing effects (p Ͻ 0.05) for the combination treatment for IL-8, IL-6, TNF␣, GM-CSF, IL-1ra, IL-10, MDC, and RANTES in one or more subject groups. Dexamethasone had no effect on LPS-induced p38 MAPK activation. We conclude that p38 MAPK activation in alveolar macrophages is corticosteroid-insensitive. Combining a p38 MAPK inhibitor with a corticosteroid synergistically enhances the antiinflammatory effects on LPS-mediated cytokine production by alveolar macrophages from patients with COPD and controls.

Neutrophil Chemotaxis Caused by Chronic Obstructive Pulmonary Disease Alveolar Macrophages: The Role of CXCL8 and the Receptors CXCR1/CXCR2

“…These experiments further confirmed that CXCR2 antagonism alone through SB656933 was less effective than dual antagonism of CXCR1 and CXCR2 using Sch527123 in this chemotaxis model. There was no difference in the effect of dexamethasone between patients with COPD and smokers in the current study, in agreement with our previous work (Jones et al, 1996;Armstrong et al, 2011;Southworth et al, 2012). Alveolar macrophage numbers are increased in patients with COPD compared with controls (Di Stefano et al, 1998;Barnes, 2004;Hogg et al, 2004), contributing to an increased burden of inflammatory mediators found in the lungs of patients with COPD such as CXCL8 (Yamamoto et al, 1997).…”

“…Alveolar macrophage numbers are increased in patients with COPD compared with controls (Di Stefano et al, 1998;Barnes, 2004;Hogg et al, 2004), contributing to an increased burden of inflammatory mediators found in the lungs of patients with COPD such as CXCL8 (Yamamoto et al, 1997). The production of CXCL8 by macrophages is only partially suppressed by corticosteroids in patients with both COPD and controls (Jones et al, 1996;Armstrong et al, 2011), but this limited effect is more clinically relevant in patients with COPD as the levels of CXCL8 after corticosteroid treatment still cause neutrophil chemotaxis. CXCL8 release is inhibited by 68% by dexamethasone (Fig.…”

“…Corticosteroids incompletely suppress the production of neutrophil chemokines, such as CXCL1 and CXCL8, by alveolar macrophages (Standiford et al, 1992;Armstrong et al, 2009Armstrong et al, , 2011. There is a need for novel therapies that inhibit the actions of neutrophil chemokines.…”

Effects of cigarette smoke on Toll-like receptor (TLR) activation of chronic obstructive pulmonary disease (COPD) macrophages

“…Western blots were run as described previously [20]. All primary antibodies were raised in rabbit: phospho-p38 MAPK (Th180/Tyr182) antibody (Cell Signalling, Hitchin, UK), phospho-p44/42 MAPK (ERK1/2) (Thr202/Tyr204) antibody (Cell Signalling), phospho-NF-κB p65 (Ser536) antibody (Cell Signalling) and β-actin antibody (Abcam) as loading control.…”

The effect of peroxisome proliferator-activated receptor- ligands on in vitro and in vivo models of COPD

“…Corticosteroids only partially suppress cytokine production from COPD alveolar macrophages [18][19][20]. There is an urgent need for more effective antiinflammatory therapies for COPD that target macrophage function.…”