title: Modulating and Measuring Intracellular H2O2Using Genetically Encoded Tools to Study Its Toxicity to Human Cells.
abstract: Reactive oxygen species (ROS) such as H2O2play paradoxical roles in mammalian physiology. It is hypothesized that low, baseline levels of H2O2are necessary for growth and differentiation, while increased intracellular H2O2concentrations are associated with pathological phenotypes and genetic instability, eventually reaching a toxic threshold that causes cell death. However, the quantities of intracellular H2O2that lead to these different responses remain an unanswered question in the field. To address this question, we used genetically encoded constructs that both generate and quantify H2O2in a dose-response study of H2O2-mediated toxicity. We found that, rather than a simple concentration-response relationship, a combination of intracellular concentration and the cumulative metric of H2O2concentration multiplied by time (i.e., the area under the curve) determined the occurrence and level of cell death. Establishing the quantitative relationship between H2O2and cell toxicity promotes a deeper understanding of the intracellular effects of H2O2specifically as an individual reactive oxygen species, and it contributes to an understanding of its role in various redox-related diseases.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Beijing K
authors.initials: BK
authors.lastname: Huang
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Kassi T
authors.initials: KT
authors.lastname: Stein
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Hadley D
authors.initials: HD
authors.lastname: Sikes
mesh_terms: D017209:Apoptosis; D003593:Cytoplasm / Q000737:chemistry*; D042822:Genomic Instability; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000633:toxicity*
chemical_list: D006861:Hydrogen Peroxide
keywords: HyPer; chemotherapeutics; d-amino acid oxidase; hydrogen peroxide; quantitative redox biology; toxicity