Toxification of polycyclic aromatic hydrocarbons by commensal bacteria from human skin

• Published in: Archives of toxicology 2017-06, Vol.91 (6), p.2331-2341
• Main Authors: Sowada, Juliane, Lemoine, Lisa, Schön, Karsten, Hutzler, Christoph, Luch, Andreas, Tralau, Tewes
• Format: Article
• Language: English
• Subjects: Bacillus licheniformis - genetics; Bacillus licheniformis - metabolism; Bacteria; Benzo(a)pyrene; Biomedical and Life Sciences; Biomedicine; Carbon sources; Carcinogens; Cell Line; Cell Survival - drug effects; Comet Assay; Commensals; Deoxyribonucleic acid; DNA; DNA adducts; DNA Damage; Energy sources; Environmental Health; Gas Chromatography-Mass Spectrometry; Genotoxicity; Humans; Ingestion; Keratinocytes - drug effects; Keratinocytes - metabolism; Keratinocytes - microbiology; Metabolic Detoxication, Phase I; Metabolism; Metabolites; Microbiota; Micrococcus luteus - genetics; Micrococcus luteus - metabolism; Molecular weight; Occupational Medicine/Industrial Medicine; Pharmacology/Toxicology; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - toxicity; Pyrene; Skin; Skin - drug effects; Skin - metabolism; Skin - microbiology; Toxicity; Toxicokinetics and Metabolism
• ISSN: 0340-5761; 1432-0738
• DOI: 10.1007/s00204-017-1964-3

The ubiquitous occurrence of polycyclic aromatic hydrocarbons (PAHs) leads to constant human exposure at low levels. Toxicologically relevant are especially the high-molecular weight substances due to their (pro-)carcinogenic potential. Following ingestion or uptake, the eukaryotic phase I metabolism often activates these substances to become potent DNA binders, and unsurprisingly metabolism and DNA-adduct formation of model substances such as benzo[ a ]pyrene (B[ a ]P) are well studied. However, apart from being subjected to eukaryotic transformations PAHs are also carbon and energy sources for the myriads of commensal microbes inhabiting man’s every surface. Yet, we know little about the microbiome’s PAH-metabolism capacity and its potentially adverse impact on the human host. This study now shows that readily isolable skin commensals transform B[ a ]P into a range of highly cyto- and genotoxic metabolites that are excreted in toxicologically relevant concentrations during growth. The respective bacterial supernatants contain a mixture of established eukaryotic as well as hitherto unknown prokaryotic metabolites, the combination of which leads to an increased toxicity. Altogether we show that PAH metabolism of the microbiome has to be considered a potential hazard.