Polychlorinated Biphenyl-Related Alterations of the Expression of Essential Genes in Harbour Seals (Phoca vitulina) from Coastal Sites in Canada and the United States.

Arch Environ Contam Toxicol. 2017 May 20. doi: 10.1007/s00244-016-0362-9. [Epub ahead of print] Noël M1, Dangerfield N2, Jeffries S3, Lambourn D3, Lance M3, Helbing C4, Lebeuf M5, Ross PS6. Author information 1 Ocean Pollution Research Program, Coastal Ocean Research Institute, Vancouver Aquarium Marine Science Centre, PO Box 3232, Vancouver, BC, V6B 3X8, Canada. marie.noel@vanaqua.org. 2 Institute of Ocean Sciences, Fisheries and Oceans, PO Box 6000, Sidney, BC, V8L 4B2, Canada. 3 Washington Department of Fish and Wildlife, Lakewood, WA, 98498, USA. 4 Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 3P6, Canada. 5 Institut Maurice-Lamontagne, Fisheries and Oceans Canada, Mont-Joli, QC, G5H 3Z4, Canada. 6 Ocean Pollution Research Program, Coastal Ocean Research Institute, Vancouver Aquarium Marine Science Centre, PO Box 3232, Vancouver, BC, V6B 3X8, Canada. Abstract As long-lived marine mammals found throughout the temperate coastal waters of the North Pacific and Atlantic Oceans, harbour seals (Phoca vitulina) have become an invaluable sentinel of food-web contamination. Their relatively high trophic position predisposes harbour seals to the accumulation of harmful levels of persistent organic pollutants (POPs). We obtained skin/blubber biopsy samples from live-captured young harbour seals from various sites in the northeastern Pacific (British Columbia, Canada, and Washington State, USA) as well as the northwestern Atlantic (Newfoundland and Quebec, Canada). We developed harbour seal-specific primers to investigate the potential impact of POP exposure on the expression of eight important genes. We found correlations between the blubber mRNA levels of three of our eight target genes and the dominant persistent organic pollutant in seals [polychlorinated biphenyls (PCBs)] including estrogen receptor alpha (Esr1: r 2 = 0.12, p = 0.038), thyroid hormone receptor alpha (Thra: r 2 = 0.16; p = 0.028), and glucocorticoid receptor (Nr3c1: r 2 = 0.12; p = 0.049). Age, sex, weight, and length were not confounding factors on the expression of genes. Although the population-level consequences are unclear, our results suggest that PCBs are associated with alterations of the expression of genes responsible for aspects of metabolism, growth and development, and immune function. Collectively, these results provide additional support for the use of harbour seals as indicators of coastal food-web contamination. PMID: 28528409 DOI: 10.1007/s00244-016-0362-9