Defining the transcriptomic fingerprints of benzo[a]pyrene exposure in Caenorhabditis elegans

Polycyclic aromatic hydrocarbons (PAHs) are abundant organic compounds and are anthropogenically produced by the incomplete combustion of organic matter (e.g. fossil fuels and tobacco smoke). One notable model PAH is benzo[a]pyrene (BaP), which is listed as a Group 1 human carcinogen by the International Agency of Research on Cancer (IARC). Although the mode of action for BaP is well known in higher organisms, limited knowledge is available regarding the consequence of BaP exposure in the model organism Caenorhabditis elegans. The objective of this study was to define the the global transcriptome of wild-type C. elegans exposed to BaP (0, 5 and 20 μM). The most responsive transcripts were linked to redox processes and xenobiotic responses, including P450 enzymes (CYPs) (mainly members of the CYP35 family), epoxide hydrolases (EHs), glutathione S-transferases (GSTs), and UDP-glucuronosyltransferases (UGTs), all of which are linked to the metabolism (phase I & II) of xenobiotic substances. In summary, although the dominant CYP1A1/2 & CYP1B1 metabolic pathway is absent in C. elegans, BaP still induced a strong transcriptomic response. This provides strong evidence that parallel pathway(s) are implicated in BaP metabolism, and possibly, in its detoxification. The global transcriptome was compared in wild type N2 raised in the presence or absence of benzo[a]pyrene at the concentration of 0,5 or 20 μM for for 48 hours from L1 stage to L4 stage.