Science Inventory

Resistance to Cyp3a induction by polychlorinated biphenyls, including non-dioxin-like PCB153, in gills of killifish (Fundulus heteroclitus) from New Bedford Harbor

Citation:

Celander, M., J. Goldstone, N. Brun, B. Clark, S. Jayaraman, D. Nacci, AND J. Stegeman. Resistance to Cyp3a induction by polychlorinated biphenyls, including non-dioxin-like PCB153, in gills of killifish (Fundulus heteroclitus) from New Bedford Harbor. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY. Elsevier Science Ltd, New York, NY, 83:103580, (2021). https://doi.org/10.1016/j.etap.2020.103580

Impact/Purpose:

Induction of cytochrome P450 1a (Cyp1a) has long been used as a biomarker of exposure to dioxin-like polychlorinated biphenyls (PCB) and other aryl hydrocarbon receptor (AHR) agonists in the aquatic environment. In contrast to the dioxin-like PCBs (DL PCBs), the molecular effects of non-dioxin-like PCBs (NDL PCBs) in fish are less well known, even though they are vastly more abundant in the environment. In this study, we investigated the molecular effects of the NDL PCBs including validating an exposure biomarker, and investigating a possible molecular adaptation to high levels of NDL PCBs, in the estuarine fish model, Atlantic killifish (Fundulus heteroclitus). Furthermore, this study examines these responses during exposure to a mixture of both DL and NDL PCBs. Ultimately, this study contributes to a better understanding of the effects and markers of exposure to an imporant class of persistent environmental contaminants.

Description:

Previous reports suggested that non-dioxin-like (NDL) PCB153 effects on cytochrome P450 3A (Cyp3a) expression in Atlantic killifish (Fundulus heteroclitus) gills differed between F0 generation fish from a PCB site (New Bedford Harbor; NBH) and a reference site (Scorton Creek; SC). Here, we examined effects of PCB153, dioxin-like (DL) PCB126, or a mixture of both, on Cyp3a56 mRNA in killifish generations removed from the wild, without environmental PCB exposures. PCB126 effects in liver and gills differed between populations, as expected. Gill Cyp3a56 was not affected by either congener in NBH F2 generation fish, but was induced by PCB153 in SC F1 fish, with females showing a greater response. PCB153 did not affect Cyp3a56 in liver of either population. Results suggest a heritable resistance to NDL-PCBs in killifish from NBH, in addition to that reported for DL PCBs. Induction of Cyp3a56 in gills may be a biomarker of exposure to NDL PCBs in fish populations that are not resistant to PCBs.