Dr. Cho's laboratory utilizes chemical approaches to conduct research in biotransformation reactions and their role in the actions for foreign compounds such as drugs and environmental chemical species. The biotransformation studies investigate mechanisms of oxidation of foreign compounds by cytochrome P450, an enzyme system capable of oxidizing the carbon atom of a variety of functional groups including ethers, olefins and amines. Since many of the reaction products of this system are pharmacologically or toxicologically active, their formation is important in understanding drug action. Currently the laboratory is engaged in air pollution toxicology, having developed chemical approaches to the understanding of adverse effects associate with air pollutants. In this work, the chemical basis for pro-oxidant and electrophilic properties of air pollutants has been studied and its relationship to the inflammatory and adaptive responses associated with these pollutants determined. This approach is now being applied to a study examining the relationship between air pollutants and effects on transgenic animals with a propensity to develop a Parkinson-like syndrome, characterized by movement deficits and neurochemical changes.
Li N, Sioutas C, Cho A, Schmitz D, Misra C, Sempf J, Wang M, Oberley T, Froines J and Nel A (2003) Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage. Environ Health Perspect 111:455-460.
Cho A, Di Stefano E, Ying Y, Rodriguez CE, Schmitz D, Kumagai Y, Miguel AH, Eiguren-Fernandez A, Kobayashi T, Avol E and JR F (2004) Determination of Four Quinones in Diesel Exhaust Particles, SRM 1649a and Atmospheric PM2.5. Aerosol Science and Technology 38:68-81.
Li N, Alam J, Venkatesan MI, Eiguren-Fernandez A, Schmitz D, Di Stefano E, Slaughter N, Killeen E, Wang X, Huang A, Wang M, Miguel AH, Cho A, Sioutas C and Nel AE (2004) Nrf2 is a key transcription factor that regulates antioxidant defense in macrophages and epithelial cells: protecting against the proinflammatory and oxidizing effects of diesel exhaust chemicals. J Immunol 173:3467-3481.
Cho AK, Sioutas C, Miguel AH, Kumagai Y, Schmitz DA, Singh M, Eiguren-Fernandez A and Froines JR (2005) Redox activity of airborne particulate matter at different sites in the Los Angeles Basin. Environ Res 99:40-47.
Kleinman MT, Hamade A, Meacher D, Oldham M, Sioutas C, Chakrabarti B, Stram D, Froines JR and Cho AK (2005a) Inhalation of concentrated ambient particulate matter near a heavily trafficked road stimulates antigen-induced airway responses in mice. J Air Waste Manag Assoc 55:1277-1288.
Kikuno S, Taguchi K, Iwamoto N, Yamano S, Cho AK, Froines JR and Kumagai Y (2006) 1,2-Naphthoquinone activates vanilloid receptor 1 through increased protein tyrosine phosphorylation, leading to contraction of guinea pig trachea. Toxicol Appl Pharmacol 210:47-54.
Ntziachristos L, Froines JR, Cho AK and Sioutas C (2007) Relationship between redox activity and chemical speciation of size-fractionated particulate matter. Part Fibre Toxicol 4:5.
Ayres JG, Borm P, Cassee FR, Castranova V, Donaldson K, Ghio A, Harrison RM, Hider R, Kelly F, Kooter IM, Marano F, Maynard RL, Mudway I, Nel A, Sioutas C, Smith S, Baeza-Squiban A, Cho A, Duggan S and Froines J (2008) Evaluating the toxicity of airborne particulate matter and nanoparticles by measuring oxidative stress potential--a workshop report and consensus statement. Inhal Toxicol 20:75-99.
Eiguren-Fernandez A, Miguel A, Di Stefano E, Schmitz DC, AK, Thurairatnam S, Avol E and Froines J (2008) Atmospheric Distribution of Gas- and Particle-Phase Quinones in Southern California Aerosol Science and Technology 42:854-861.
Eiguren-Fernandez A, Miguel A, Lu R, Purvis K, Grant B, Mayo P, Di Stefano W, Cho A and Froines J (2008) Atmospheric formation of 9,10-phenantrhoquinone in the Los Angeles air basin. Atmospheric Environment 42 2312-2319.
Hu S, Polidori A, Arhami M, Schauer J, Cho A and Sioutas C (2008) Redox Activity and Chemical Speciation of Size Fractioned PM in the Communities of the Los Angeles - Long Beach Harbor. Atmospheric Chemistry and Physics 8:6439-6451.
Shinyashiki M, Rodriguez CE, Di Stefano EW, Sioutas C, Delfino RJ, Kumagai Y, Froines JR and Cho AK (2008) On the interaction between glyceraldehyde-3-phosphate dehydrogenase and airborne particles: Evidence for electrophilic species. . Atmospheric Environment 42:517-529.
Di Stefano E, Eiguren-Fernandez A, Delfino RJ, Sioutas C, Froines J and Cho AK (2009) Determination of metal-based hydroxyl radical generating capacity of ambient and diesel exhaust particles. Inhalation Toxicology 21:731-738.
Shinyashiki M, Eiguren-Fernandez A, Schmitz DA, Di Stefano E, Li N, Linak WP, Cho SH, Froines JR and Cho AK (2009) Electrophilic and redox properties of diesel exhaust particles. Environ Res 109:239-244.
Verma V, Ning Z, Cho AK, Schauer JJ and Shafer MMS, C. (2009) Redox activity of urban quasi-ultrafine particles from primary and secondary sources. Atmospheric Environment 43: 6360-6368.
Eiguren-Fernandez A, Shinyashiki M, Schmitz D, DiStefano E, Hinds W, Kumagai Y, Cho A and Froines J (2010) Redox and electrophilic properties of vapor- and particle-phase components of ambient aerosols. Environmental Research 110 207-212.
Iwamoto N, Nishiyama A, Eiguren-Fernandez A, Hinds W, Kumagai Y, Froines J, Cho A and Shinyashiki M (2010) Biochemical and cellular effects of electrophiles present in ambient air samples. Atmospheric Environment 44:1483-1489.
Miura T, Shinkai Y, Jiang H-Y, Iwamoto N, Sumi D, Taguchi K, Yamamoto B, Jinno H, Tanaka-Kagawa T, Cho A and Kumagai Y (2011) Initial Response and Cellular Protection through the Keap1/Nrf2 System during Exposure of Primary Mouse Hepatocytes to 1,2-Naphthoquinone. Chemical Research in Toxicology In press.
Kumagai Y, Shinkai Y, Miura T and Cho AK (2012) The chemical biology of naphthoquinones and its environmental implications. Annu Rev Pharmacol Toxicol 52:221-247.
Shinkai, Y., S. Nakajima, A. Eiguren-Fernandez, E. Di Stefano, D. A. Schmitz, J. R. Froines, A. K. Cho and Y. Kumagai (2014). "Ambient vapor samples activate the Nrf2-ARE pathway in human bronchial epithelial BEAS-2B cells." Environ Toxicol 29(11): 1292-1300.
Eiguren-Fernandez, A., E. Di Stefano, D. A. Schmitz, A. Lefol Nani Guarieiro, E. M. Salinas, E. Nasser, J. Froines and A. K. Cho (2015). "Chemical reactivities of ambient air samples in three Southern California communities." Journal of the Air & Waste Management Association. 65(3): 266-273.