engleski

Extracellular Hsp70 alters cigarette smoke-induced pro-inflammatory responses in human macrophages

Introduction: Cigarette smoke is one of the major risk factors for development of chronic obstructive pulmonary disease (COPD). Extracellular Hsp70 (eHsp70) can act as damage-associated molecular pattern (DAMP) to activate innate immune cells via Toll-like receptors (TLR) 2 and 4, promoting pro-inflammatory cytokine synthesis. Aims and objectives: We hypothesized that eHsp70 modulates pro-inflammatory responses caused by cigarette smoke in human macrophages. Therefore we aimed to explore pro-inflammatory cytokine production in THP-1 monocytic cell line and peripheral blood monocytes after co-treatment with recombinant human Hsp70 (rhHsp70) and cigarette smoke extract (CSE). Methods: We differentiated THP-1 cells with PMA and primary monocytes with M-CSF to macrophage-like cells, and treated cells with 0.3-3 µg/ml rhHsp70 and 2.5% or 5% CSE for 24 h. We measured IL-1, IL-1β, IL-6, IL-8 and TNF- by ELISA. Results: CSE alone induced secretion of IL-8, while IL-1, IL-1β, IL-6 and TNF- levels were below limit of detection. Therefore only IL-8 was measured in CSE and rhHsp70 combined treatments. In THP-1 cells, rhHsp70 did not further enhance CSE-induced IL-8 production. In contrast, CSE and rhHsp70 co-treatment caused strong increase of IL-8 level in monocyte-derived human macrophages in comparison to CSE alone. In addition, when 5% CSE was applied with 3 µg/ml rhHsp70, antagonistic type of interaction was present. Conclusions: Our results show that eHsp70 can modulate inflammatory response to CSE in human macrophages. Combined presence of eHsp70 and CSE could lead to aberrant activation of TLR2/4 receptors, which might contribute to the aggravation of chronic inflammation.

chronic obstructive pulmonary disease ; extracellular Hsp70 ; cigarette smoke ; THP-1 cell line

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