TY - JOUR
T1 - Congener-specific disposition of chiral polychlorinated biphenyls in lactating mice and their offspring
T2 - Implications for PCB developmental neurotoxicity
AU - Kania-Korwel, Izabela
AU - Lukasiewicz, Tracy
AU - Barnhart, Christopher D.
AU - Stamou, Marianna
AU - Chung, Haeun
AU - Kelly, Kevin M.
AU - Bandiera, Stelvio
AU - Lein, Pamela J
AU - Lehmler, Hans Joachim
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Chiral polychlorinated biphenyl (PCB) congeners have been implicated by laboratory and epidemiological studies in PCB developmental neurotoxicity. These congeners are metabolized by cytochrome P450 (P450) enzymes to potentially neurotoxic hydroxylated metabolites (OH-PCBs). The present study explores the enantioselective disposition and toxicity of 2 environmentally relevant, neurotoxic PCB congeners and their OH-PCB metabolites in lactating mice and their offspring following dietary exposure of the dam. Female C57BL/6N mice (8-weeks old) were fed daily, beginning 2 weeks prior to conception and continuing throughout gestation and lactation, with 3.1 mmol/kg bw/d of racemic 2,20,3,50,6- pentachlorobiphenyl (PCB 95) or 2,20,3,30,6,60-hexachlorobiphenyl (PCB 136) in peanut butter; controls received vehicle (peanut oil) in peanut butter. PCB 95 levels were higher than PCB 136 levels in both dams and pups, consistent with the more rapid metabolism of PCB 136 compared with PCB 95. In pups and dams, both congeners were enriched for the enantiomer eluting second on enantioselective gas chromatography columns. OH-PCB profiles in lactating mice and their offspring were complex and varied according to congener, tissue and age. Developmental exposure to PCB 95 versus PCB 136 differentially affected the expression of P450 enzymes as well as neural plasticity (arc and ppp1r9b) and thyroid hormone-responsive genes (nrgn and mbp). The results suggest that the enantioselective metabolism of PCBs to OH-PCBs may influence neurotoxic outcomes following developmental exposures, a hypothesis that warrants further investigation.
AB - Chiral polychlorinated biphenyl (PCB) congeners have been implicated by laboratory and epidemiological studies in PCB developmental neurotoxicity. These congeners are metabolized by cytochrome P450 (P450) enzymes to potentially neurotoxic hydroxylated metabolites (OH-PCBs). The present study explores the enantioselective disposition and toxicity of 2 environmentally relevant, neurotoxic PCB congeners and their OH-PCB metabolites in lactating mice and their offspring following dietary exposure of the dam. Female C57BL/6N mice (8-weeks old) were fed daily, beginning 2 weeks prior to conception and continuing throughout gestation and lactation, with 3.1 mmol/kg bw/d of racemic 2,20,3,50,6- pentachlorobiphenyl (PCB 95) or 2,20,3,30,6,60-hexachlorobiphenyl (PCB 136) in peanut butter; controls received vehicle (peanut oil) in peanut butter. PCB 95 levels were higher than PCB 136 levels in both dams and pups, consistent with the more rapid metabolism of PCB 136 compared with PCB 95. In pups and dams, both congeners were enriched for the enantiomer eluting second on enantioselective gas chromatography columns. OH-PCB profiles in lactating mice and their offspring were complex and varied according to congener, tissue and age. Developmental exposure to PCB 95 versus PCB 136 differentially affected the expression of P450 enzymes as well as neural plasticity (arc and ppp1r9b) and thyroid hormone-responsive genes (nrgn and mbp). The results suggest that the enantioselective metabolism of PCBs to OH-PCBs may influence neurotoxic outcomes following developmental exposures, a hypothesis that warrants further investigation.
KW - Atropisomer
KW - Chiral
KW - Cytochrome P450 enzymes
KW - Metabolites
KW - Persistent organic pollutants
KW - Plasticity
KW - Polychlorinated biphenyls
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U2 - 10.1093/toxsci/kfx071
DO - 10.1093/toxsci/kfx071
M3 - Article
C2 - 28431184
AN - SCOPUS:85022327260
VL - 158
SP - 101
EP - 115
JO - Toxicological Sciences
JF - Toxicological Sciences
SN - 1096-6080
IS - 1
M1 - kfx071
ER -