Research

Effects of PM₁₀ in human peripheral blood monocytes and J774 macrophages

DM Brown¹ , K Donaldson² and V Stone¹

¹  School of Life Sciences, Napier University, Edinburgh, UK

²  ELEGI Laboratory, Wilkie Building, University of Edinburgh, UK

author email corresponding author email

Respiratory Research 2004, 5:29doi:10.1186/1465-9921-5-29

Published:	21 December 2004

Abstract

The effects of PM₁₀, one of the components of particulate air pollution, was investigated using human monocytes and a mouse macrophage cell line (J774). The study aimed to investigate the role of these nanoparticles on the release of the pro-inflammatory cytokine TNF-α and IL-1α gene expression. We also investigated the role of intracellular calcium signalling events and oxidative stress in control of these cytokines and the effect of the particles on the functioning of the cell cytoskeleton. We showed that there was an increase in intracellular calcium concentration in J774 cells on treatment with PM₁₀ particles which could be significantly reduced with concomitant treatment with the calcium antagonists verapamil, the intracellular calcium chelator BAPTA-AM but not with the antioxidant nacystelyn or the calmodulin inhibitor W-7. In human monocytes, PM₁₀ stimulated an increase in intracellular calcium which was reduced by verapamil, BAPTA-AM and nacystelyn. TNF-α release was increased with particle treatment in human monocytes and reduced by only verapamil and BAPTA-AM. IL-1α gene expression was increased with particle treatment and reduced by all of the inhibitors. There was increased F-actin staining in J774 cells after treatment with PM₁₀ particles, which was significantly reduced to control levels with all the antagonists tested. The present study has shown that PM₁₀ particles may exert their pro-inflammatory effects by modulating intracellular calcium signalling in macrophages leading to expression of pro-inflammatory cytokines. Impaired motility and phagocytic ability as shown by changes in the F-actin cytoskeleton is likely to play a key role in particle clearance from the lung.