Activation of MAPKs in bronchial-epithelial NCI-H292 cells co-treated with extracellular Hsp70 and bacterial components or cigarette smoke extract

Abstract

Introduction: The main etiologic factor for chronic obstructive pulmonary disease (COPD), which is characterized by chronic airway inflammation, is cigarette smoking. Patients with COPD are susceptible to bacterial infections causing acute exacerbations. Extracellular Hsp70 (eHsp70) can act as damage-associated molecular pattern and activate immune cells via Toll-like receptors 2 and 4. Aims and objectives: The aim of this study was to examine the effects of recombinant human Hsp70 (rhHsp70) when present alone or together with bacterial components lipopolysaccharide (LPS) and lipoteichoic acid (LTA) as well as cigarette smoke extract (CSE) on activation of mitogen-activated protein kinases (MAPKs) signalling pathways in bronchial-epithelial NCI-H292 cell line. Methods: NCI-H292 cells were treated either with rhHsp70 (0.3, 1.0 or 3.0 µg/mL), 0.1 µg/ml LPS, 1 µg/ml LTA and CSE (2.5% or 15%) alone, or with their combinations, for 30 min, 2 h, 8 h and 24 h. Expression and activation of MAPKs (ERK, JNK and p38) were determined by Western blotting method. Results: rhHsp70, LPS, LTA and their combinations caused activation of ERK, JNK and p38 MAPK, while rhHsp70 together with CSE caused activation of ERK and p38 MAPK in NCI-H292 cells, compared to the control cells. Extent of activation was dependant on concentration and time of treatment. Conclusions: eHsp70 as well as bacterial components (LPS and LTA) and CSE activate MAPK signalling pathways in NCI-H292 cells. Combined presence of eHsp70, LPS, LTA and/or CSE might lead to worsening of COPD patients’ condition.