The Ah receptor plays a central role in the biological response to halogenated polycyclic aromatic hydrocarbons (HPAH), a major class of environmental contaminants, many of these components are known to be carcinogenic (e.g. dioxins). This receptor, upon binding a HPAH, is thought to translocate into the nucleus and induce the synthesis of enzymes involved in the metabolism of xenobiotics. The non-ligand binding protein composition of the Ah receptor complex has no been determined. Using 2-azido-3-(125I)7,8- dibromodibenzo-p-dioxin (a photoaffinity ligand), a monoclonal antibody to an Ah receptor, and cross-linking reagents, a series of experiments will be performed to determine the protein composition of the Ah receptor in the Hepa lcl cell line. Since phosphorylation is an important post-transnational modification involved in the regulation of receptor systems, and indirect evidence has suggested that the Ah receptor is phosphorylated, the studies outlined here will directly examine this possibility. Hepa 1 cells will be incubated in the presence of (32P) orthophosphate followed by the isolation of a cytosolic fraction. This preparation will be immunoprecipitated, subjected to two- dimensional gel electrophoresis, and the (32P)-labeled polypeptide pattern will be compared to photoaffinity-labeled control samples. In addition, studies will be performed to determine whether phosphorylation is required for Ah receptor ligand binding activity. The rate of Ah receptor turnover in Hepa 1 cells will be determined using a dense amino acid labeling method. The influence of ligand occupation on the rate of receptor turnover will also be determined. A number of compounds have been found to alter in vivo Ah receptor activity levels, studies will be performed to examine the ability of certain exogenous compounds to influence receptor levels in cell culture. Any differences seen can then be further examined by turnover experiments to determine if the rate of receptor synthesis has changed. The experiments proposed here will enable a better understanding of possible mechanisms of Ah receptor regulation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29ES004869-01
Application #
3465254
Study Section
Toxicology Study Section (TOX)
Project Start
1989-01-01
Project End
1993-12-31
Budget Start
1989-01-01
Budget End
1989-12-31
Support Year
1
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Purdue University
Department
Type
Sch of Home Econ/Human Ecology
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907
Lahoti, Tejas S; Boyer, Jacob A; Kusnadi, Ann et al. (2015) Aryl Hydrocarbon Receptor Activation Synergistically Induces Lipopolysaccharide-Mediated Expression of Proinflammatory Chemokine (c-c motif) Ligand 20. Toxicol Sci 148:229-40
Hubbard, Troy D; Murray, Iain A; Bisson, William H et al. (2015) Adaptation of the human aryl hydrocarbon receptor to sense microbiota-derived indoles. Sci Rep 5:12689
Hubbard, Troy D; Murray, Iain A; Perdew, Gary H (2015) Indole and Tryptophan Metabolism: Endogenous and Dietary Routes to Ah Receptor Activation. Drug Metab Dispos 43:1522-35
Zhang, Limin; Hatzakis, Emmanuel; Nichols, Robert G et al. (2015) Metabolomics Reveals that Aryl Hydrocarbon Receptor Activation by Environmental Chemicals Induces Systemic Metabolic Dysfunction in Mice. Environ Sci Technol 49:8067-77
Zhang, Limin; Nichols, Robert G; Correll, Jared et al. (2015) Persistent Organic Pollutants Modify Gut Microbiota-Host Metabolic Homeostasis in Mice Through Aryl Hydrocarbon Receptor Activation. Environ Health Perspect 123:679-88
Borland, Michael G; Krishnan, Prasad; Lee, Christina et al. (2014) Modulation of aryl hydrocarbon receptor (AHR)-dependent signaling by peroxisome proliferator-activated receptor ?/? (PPAR?/?) in keratinocytes. Carcinogenesis 35:1602-12
Fang, Zhong-Ze; Krausz, Kristopher W; Nagaoka, Kenjiro et al. (2014) In vivo effects of the pure aryl hydrocarbon receptor antagonist GNF-351 after oral administration are limited to the gastrointestinal tract. Br J Pharmacol 171:1735-46
Murray, Iain A; Patterson, Andrew D; Perdew, Gary H (2014) Aryl hydrocarbon receptor ligands in cancer: friend and foe. Nat Rev Cancer 14:801-14
John, Kaarthik; Lahoti, Tejas S; Wagner, Kelly et al. (2014) The Ah receptor regulates growth factor expression in head and neck squamous cell carcinoma cell lines. Mol Carcinog 53:765-76
Lahoti, Tejas S; Hughes, Jarod M; Kusnadi, Ann et al. (2014) Aryl hydrocarbon receptor antagonism attenuates growth factor expression, proliferation, and migration in fibroblast-like synoviocytes from patients with rheumatoid arthritis. J Pharmacol Exp Ther 348:236-45

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