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High Content Screening Analysis to Evaluate the Toxicological Effects of Harmful and Potentially Harmful Constituents (HPHC)
Published on: May 10, 2016
New method for testing phototoxicity of polycyclic aromatic hydrocarbons
1Laboratory of Radiation Biology, Graduate School of Nutritional and Environmental Sciences, Institute for Environmental Sciences, University of Shizuoka, Shizuoka, Japan.
Environmental Science & Technology
|June 22, 2006
Summary
Histone H2AX phosphorylation (gamma-H2AX) offers a sensitive method for detecting polycyclic aromatic hydrocarbon (PAH) phototoxicity. This new assay detects PAH effects at lower concentrations than traditional DNA double-strand break or cell viability tests.
Area of Science:
- Environmental Science
- Toxicology
- Molecular Biology
Background:
- Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants known to cause photomutagenesis.
- Assessing the phototoxic potential of PAHs upon sunlight exposure is crucial for environmental risk evaluation.
- Previous studies indicated that histone H2AX phosphorylation (gamma-H2AX) correlates with DNA double-strand breaks (DSBs) induced by benzo[a]pyrene and UVA.
Purpose of the Study:
- To investigate the utility of gamma-H2AX as a sensitive biomarker in a novel phototoxicity assay for PAHs.
- To compare the sensitivity of gamma-H2AX induction with direct DSB detection and cell viability assays for PAH phototoxicity.
Main Methods:
- Human keratinocytes (HaCaT) were exposed to four model PAHs (naphthalene, phenanthrene, pyrene, benzo[a]pyrene) and/or UVA radiation.
- Gamma-H2AX induction was assessed using specific assays.
- DNA double-strand breaks (DSBs) were quantified via biased sinusoidal field gel electrophoresis, and cell viability was measured.
Main Results:
- Gamma-H2AX was induced by phenanthrene, pyrene, and benzo[a]pyrene at concentrations of 10(-9)-10(-7) M, but not by naphthalene.
- No significant DSBs or cell death were detected at these concentrations, requiring higher PAH levels for such observations.
- Naphthalene exhibited no phototoxicity across all tested assays.
Conclusions:
- Histone H2AX phosphorylation (gamma-H2AX) serves as a sensitive indicator for PAH phototoxicity.
- The gamma-H2AX assay detects phototoxic effects of PAHs at lower concentrations compared to DSB detection and cell viability assays.
- This suggests gamma-H2AX is a promising molecular target for a more sensitive PAH phototoxicity assessment.
