Meeting Abstract

P1.25  Wednesday, Jan. 4  AHR-1, AHR-2, AND CYP1A EXPRESSION IN TISSUES OF CREOSOTE-ADAPTED ATLANTIC KILLIFISH (FUNDULUS HETEROCLITUS) FROM THE ELIZABETH RIVER, VA USA WOJDYLO, J.E.; RICE, C.D.*; Clemson University, Clemson SC; Clemson University, Clemson SC cdrice@clemson.edu

The Atlantic Wood (AW) creosote facility on the Elizabeth River, Portsmouth VA, is a declared EPA Superfund site. Compared to a reference population, AW killifish are shown to be resistant to PAH-related embryo toxicity and recalcitrant to CYP1A induction by PAHs, yet a large percentage of fish harbored extensive hepatic lesions. In 2010 we examined AW killifish to determine if CYP1A expression remains low, if the frequency of hepatic lesions remains high, and to describe the expression of AhR in these fish. Using an expression plasmid, we expressed recombinant killifish AhR-1 and AhR-2 to generate mAbs, resulting in mAbs 7B8 and 5B6 respectively. Head kidneys (HK), intestines, and livers were isolated from AW and reference killifish (Kings Creek, Gloucester County VA) and processed for histological evaluation and immunohistochemistry (IHC). We find that the frequency of liver lesions is very high, including a high percentage of neoplasia. We find that CYP1A expression (using mAb C10-7) is very low to absent in hepatic lesions, detectable in normal hepatic tissues, but highly expressed in intestinal epithelia and HK of AW fish. Low CYP1A expression was detected in fish from the reference site. AhR-1 protein is not abundantly detectable in any of the tissues examined. AhR-2 is highly expressed in all tissues of both populations, but much higher in AW fish. Interestingly, while many hepatic lesions in AW fish express very low levels of CYP1A, these same lesions express higher levels of AhR-2 than surrounding normal tissue. Our study shows that AW killifish remain an important model for understanding the relationship between the AhR and acquired resistance to PAHs. (NIH R15-ES016905-1)