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Nanodiamond particles induce IL-8 expression through a transcript stabilization mechanism in human airway epithelial cells
Citation:
SILBAJORIS, R. A., A. J. GHIO, L. A. DAILEY, J. M. SAMET, W. Cheng, P. A. BROMBERG, I. JASPERS, T. Tal, AND J. M. Huang. Nanodiamond particles induce IL-8 expression through a transcript stabilization mechanism in human airway epithelial cells. Journal of Nanotoxicology. Taylor and Francis, Philadelphia, PA, 3(2):152-160, (2009).
Impact/Purpose:
Nanodiamond particles prepared by detonational processes have a number of industrial and analytical applications.
Description:
Nanodiamond particles (NDP) prepared by detonational processes have a number of industrial and analytical applications. Previous in vitro studies have reported NDP to be biologically inert with negligible cytotoxicity, implying that they are potentially suitable for biomedical applications such as drug delivery. However, separate studies have shown that elemental carbon particles, a material that is closely related to NDP, can induce inflammatory responses in the lung. Therefore, to assess the potential toxicity ofexposure to NDP, we examined its effects on IL-8 expression by human airway epithelial cells (HAEC) in vitro. Four-hour exposures ofHAEC to 66 JLg/ml NDP resulted in IL-8 mRNA increases up to 70-fold over control levels and were accompanied by up to 14fold increases in IL-8 protein levels in the media. Adenoviral overexpression ofcatalase significantly reduced NDP-induced IL-8 mRNA expression in HAEC. Interestingly, exposure to NDP did not increase IL-8 transcriptional activity, as measured with the use ofIL-8 promoter reporter constructs. Rather, NDP treatment was found to markedly increase the half-life ofIL8-mRNA transcripts in HAEC. These findings show a pronounced increase in the expression ofIL-8 in HAEC, suggesting that NDP inhalation can cause inflammatory responses in the human lung.
