Differential Effects of p38, MAPK, PI3K or Rho Kinase Inhibitors on Bacterial Phagocytosis and Efferocytosis by Macrophages in COPD.

Martin A Bewley,Moira K B Whyte,Jadwiga A Wedzicha,Iain Kilty,Kirandeep K Chana,Dave Singh,Richard C Budd,Kylie B R Belchamber,Copdmap ,Peter J Barnes,David H Dockrell,Louise E Donnelly,Christopher E Brightling,Gavin Donaldson

doi:10.1371/journal.pone.0163139

Abstract

Pulmonary inflammation and bacterial colonization are central to the pathogenesis of chronic obstructive pulmonary disease (COPD). Defects in macrophage phagocytosis of both bacteria and apoptotic cells contribute to the COPD phenotype. Small molecule inhibitors with anti-inflammatory activity against p38 mitogen activated protein kinases (MAPKs), phosphatidyl-inositol-3 kinase (PI3K) and Rho kinase (ROCK) are being investigated as novel therapeutics in COPD. Concerns exist, however, about off-target effects. We investigated the effect of p38 MAPK inhibitors (VX745 and SCIO469), specific inhibitors of PI3K α (NVS-P13K-2), δ (NVS-P13K-3) or γ (NVS-P13K-5) and a ROCK inhibitor PF4950834 on macrophage phagocytosis, early intracellular killing of bacteria and efferocytosis of apoptotic neutrophils. Alveolar macrophages (AM) obtained from broncho-alveolar lavage (BAL) or monocyte-derived macrophages (MDM) from COPD patients (GOLD stage II/III) enrolled from a well characterized clinical cohort (MRC COPD-MAP consortium) or from healthy ex-smoker controls were studied. Both COPD AM and MDM exhibited lower levels of bacterial phagocytosis (using Streptococcus pneumoniae and non-typeable Haemophilus influenzae) and efferocytosis than healthy controls. None of the inhibitors altered bacterial internalization or early intracellular bacterial killing in AM or MDM. Conversely PF4950834, but not other inhibitors, enhanced efferocytosis in COPD AM and MDM. These results suggest none of these inhibitors are likely to exacerbate phagocytosis-related defects in COPD, while confirming ROCK inhibitors can enhance efferocytosis in COPD.

Highlights

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung condition in which patients suffer progressive worsening of lung function characterised by an obstructive pattern of airflow limitation, which is only partially reversible [1, 2]
In order to establish that any modification of macrophage responses observed was not due to compounds affecting cell viability, alveolar macrophages from healthy donors or COPD patients were assessed for apoptosis (Fig 1A–1C) or necrosis (Fig 1D–1F) after treatment with p38 inhibitors SCIO469 and VX745 (Fig 1A and 1D), phosphatidyl-inositol-3 kinase (PI3K) inhibitors NVS-PI3-2, NVS-PI3-3 or NVS-PI3-5 (Fig 1B and 1E) or the Rho-associated protein kinase (ROCK) inhibitor PF4950834 (Fig 1C and 1F) for 20 h
To further check the efficacy of the compounds we looked at their ability to modulate pro-inflammatory cytokine production from alveolar macrophages

Summary

Introduction

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung condition in which patients suffer progressive worsening of lung function characterised by an obstructive pattern of airflow limitation, which is only partially reversible [1, 2]. Patients with COPD have an accelerated decline in lung function and experience episodes of acute exacerbations, associated with increased lung inflammation. These events are a common cause of hospitalization [4, 5] and impose a considerable financial burden on health services. The increased incidence of pneumonia in COPD itself and with ICS use emphasises the importance of developing alternative treatment strategies that do not further exacerbate the altered innate immune responses observed in COPD. A variety of small molecule kinase inhibitors are being investigated as novel therapeutics with which to treat airway inflammation[11] and several have potential therapeutic value in COPD [12] [13]

Methods

Results

Conclusion