Unknown

Dataset Information

0

Dioxin Exposure Alters Molecular and Morphological Responses to Thyroid Hormone in Xenopus laevis Cultured Cells and Prometamorphic Tadpoles.


ABSTRACT: Amphibian metamorphosis is driven by thyroid hormone (TH). We used prometamorphic tadpoles and a cell line of the African clawed frog (Xenopus laevis) to examine immediate effects of dioxin exposure on TH. Gene expression patterns suggest cross-talk between the thyroid hormone receptor (TR) and aryl hydrocarbon receptor (AHR) signaling pathways. In XLK-WG cells, expression of Cytochrome P450 1A6 (cyp1A6), an AHR target, was induced 1000-fold by 100 nM TCDD (2, 3, 7, 8 tetrachlorodibenzo-p-dioxin). Krüppel-Like Factor 9 (klf9), the first gene induced in a cascade of TH responses tied to metamorphosis, was upregulated over 5-fold by 50 nM triiodothyronine (T3) and 2-fold by dioxin. Co-exposure to T3 and TCDD boosted both responses, further inducing cyp1A6 by 75% and klf9 about 60%. Additional canonical targets of each receptor, including trβa and trβb (TR) and udpgt1a (AHR) responded similarly. Induction of TH targets by TCDD in XLK-WG cells predicts that exposure could speed metamorphosis. We tested this hypothesis in two remodeling events: tail resorption and hind limb growth. Resorption of ex vivo cultured tails was accelerated by 10 nM T3, while a modest increase in resorption by 100 nM TCDD lacked statistical significance. Hind limbs doubled in length over four days following 1 nM T3 treatment, but limb length was unaffected by 100 nM TCDD. TCDD co-exposure reduced the T3 effect by nearly 40%, despite TCDD induction of klf9 in whole tadpoles, alone or with T3. These results suggest that tissue-specific TCDD effects limit or reverse the increased metamorphosis rate predicted by klf9 induction.

SUBMITTER: Taft JD 

PROVIDER: S-EPMC5837452 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

altmetric image

Publications

Dioxin Exposure Alters Molecular and Morphological Responses to Thyroid Hormone in Xenopus laevis Cultured Cells and Prometamorphic Tadpoles.

Taft Justin D JD   Colonnetta Megan M MM   Schafer Rachel E RE   Plick Natalie N   Powell Wade H WH  

Toxicological sciences : an official journal of the Society of Toxicology 20180101 1


Amphibian metamorphosis is driven by thyroid hormone (TH). We used prometamorphic tadpoles and a cell line of the African clawed frog (Xenopus laevis) to examine immediate effects of dioxin exposure on TH. Gene expression patterns suggest cross-talk between the thyroid hormone receptor (TR) and aryl hydrocarbon receptor (AHR) signaling pathways. In XLK-WG cells, expression of Cytochrome P450 1A6 (cyp1A6), an AHR target, was induced 1000-fold by 100 nM TCDD (2, 3, 7, 8 tetrachlorodibenzo-p-dioxin  ...[more]

Similar Datasets

| S-EPMC6692881 | biostudies-literature
| S-EPMC9007347 | biostudies-literature
| S-EPMC26638 | biostudies-literature
| S-EPMC1241106 | biostudies-other
| S-EPMC9790228 | biostudies-literature
2006-11-08 | E-MNIA-94 | biostudies-arrayexpress
| S-EPMC1618110 | biostudies-literature
| S-EPMC5133355 | biostudies-literature
2005-10-04 | GSE3402 | GEO
2016-12-23 | GSE56012 | GEO