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Measuring the Bioenergetic Effects of 1,2-Naphthoquinone Exposure on Human Lung Macrophages Using Seahorse Extracellular Flux Analyses
Citation:
Lavrich, K., N. Alexis, AND J. Samet. Measuring the Bioenergetic Effects of 1,2-Naphthoquinone Exposure on Human Lung Macrophages Using Seahorse Extracellular Flux Analyses. Society of Toxicology, Baltimore, MD, March 12 - 17, 2017.
Impact/Purpose:
Abstract of a proposed presentation at the 2017 Annual Meeting of the Society of Toxicology. This work reports findings from a mechanistic study investigating bioenergetics effects of air pollutants on human alveolar macrophages. The study uses a novel approach to investigate the effects of ambient air pollutants on human health.
Description:
Exposure to ambient particulate matter (PM) is one of the leading causes of morbidity and mortality in humans. Quinones are organic PM components that induce inflammatory responses through redox cycling and electrophilic attack. 1,2-naphthoquinone (1,2-NQ) has previously been shown to cause bioenergetic effects in airway epithelial cells, but the effects in macrophages (Mac) are unknown. Induced sputum and bronchoalveolar lavage (BAL) are procedures that recover Mac from the central and peripheral airways, respectively and can be used to assess the impact of environmental agents on Mac function. In this study, we sought to characterize the bioenergetic effects of ex vivo exposure to 1,2-NQ on Mac derived from induced sputum or BAL in healthy human volunteers. We optimized techniques for analyzing primary airway samples on the Seahorse XFe24 Analyzer and assessed mitochondrial respiration and glycolytic activity in response to 1,2-NQ exposure. In sputum samples, the oxygen consumption rate (OCR) increase induced by 1,2-NQ was very small when compared to the robust oxidative burst response to the protein kinase C activator phorbol 12-myristate 13-acetate (PMA). In contrast, 1,2-NQ produced a greater OCR increase than that of PMA in BAL Mac. Both BAL and sputum Mac had lower 1,2-NQ induced OCR increases than bronchial epithelial cells, suggesting that Mac may have a lower capacity for quinone redox cycling. Differential responses in response to 1,2-NQ between BAL and sputum samples show Mac from lower airways, and to a greater extent, epithelial cells, may be more susceptible to oxidative damage by quinones. To our knowledge, this is a novel application of extracellular flux methodology to lung Mac acquired from human volunteers. Bioenergetic effects of ex vivo exposure to an environmental agent were successfully examined. The observed inter-lung compartment variability indicates that certain human Mac populations may be more susceptible to PM-associated quinones based on their anatomic location in the lung. This further elucidates the mechanisms underlying PM-induced health effects.This abstract does not necessarily reflect EPA policy.