Inflammatory cell signaling following exposures to particulate matter and ozone

Background: Particulate matter (PM) and ozone (O-3) are two major ambient air pollutants. Epidemiological and toxicological studies have demonstrated exposure to these pollutants is associated with a variety of adverse health effects, including cardiovascular and respiratory disease, in which inflammation is believed to be a common and essential factor. Scope of review: This review mainly focuses on major inflammatory cell signaling pathways triggered by exposure to PM and O-3. The receptors covered in this review include the EGF receptor, toll like receptor, and NOD-like receptor. Intracellular signaling protein kinases depicted in this review are phosphatidylinositol 3-kinase and mitogen-activated protein kinases. Activation of antioxidant and inflammatory transcription factors such as NrF2 and NF kappa B induced by PM and O-3 is also discussed. Major conclusions: Exposure to PM or O-3 can activate cellular signaling networks including membrane receptors, intracellular kinases and phosphatases, and transcription factors that regulate inflammatory responses. While PM induced cell signaling is associated with resultant ROS, O-3-induced cell signaling implicates phosphates. Notably, the cellular signaling induced by PM and O-3 exposure varies with cell type and physiochemical properties of these pollutants. General significance: Cellular signaling plays a critical role in the regulation of inflammatory pathogenesis. Elucidation of cellular signaling pathways initiated by PM or O-3 cannot only help to uncover the mechanisms of air pollutant toxicity but also provide clues for development of interventional measures against air pollution-induced disorders. (C) 2016 Elsevier B.V. All rights reserved.