Oxidative lipidomics of macrophage activation and apoptosis induced by phagocytosis of particles and pathogens.
Feng-W; Tyurin-VA; Go-KL; Tyurina-YY; Stewart-NA; Fazzi-F; Kisin-ER; Murray-AR; Shvedova-AA; Pitt-B; Ortiz-LA; Kagan-VE
Toxicologist 2009 Mar; 108(1):194
Macrophages are essential to the innate immune system in eliminating invading microorganisms and as major orchestrators of the inflammatory response. As pathogens undergo phagocytosis and intracellular digestion; this mechanism can lead to apoptosis of the phagocyte. However, the mechanisms of apoptosis and its links with phagocytosis are largely unknown. We hypothesized that triggering of phagocytosis and activation of macrophages - including NADPH oxidase generated derived reactive oxygen species - mediates selective oxidation of phospholipids participating in the execution of apoptotic program. To approach this, zymosan, silica particles and carbon nanotubes were utilized as different types of pathogens/particles capable of activating macrophage in vitro and/or in vivo. Macrophage cell lines (RAW 264.7 and IC-21) as well as C57Bl/6 mice were treated with one of the above and NADPH oxidase activation, superoxide generation, cytochrome c release, PS externalization and caspase 3/7 activity were used to confirm the apoptotic cell death. Oxidation of major classes of phospholipids - phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and cardiolipin (CL) - was determined by electro-spray ionization mass spectrometry as well as by fluorescence HPLC/Amplex Red assay. The results demonstrated that robust and selective peroxidation of anionic phospholipids (CL>> PS >PI) accompanied macrophage apoptosis in vitro. Moreover, oxidation of the same species of anionic phospholpipids was detected in lungs of mice exposed to single walled carbon nanotubes via pharengeal inhalation. We conclude that anionic phospholipid-mediated signaling may participate in phagocytosis induced macrophage apoptosis.
Absorption-rates; Biological-effects; Biological-factors; Cell-damage; Cell-morphology; Cellular-reactions; Exposure-assessment; Exposure-levels; Exposure-methods; Immunology; Inhalation-studies; Laboratory-animals; Lung-cells; Lung-tissue; Molecular-biology; Oxidative-metabolism; Oxidative-processes; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Statistical-analysis; Nanotechnology
The Toxicologist. Society of Toxicology 48th Annual Meeting and ToxExpo, March 15-19, 2009, Baltimore, Maryland
University of Pittsburgh at Pittsburgh