Some environmental contaminants such as 2.3.7.8 tetrachlorodibenzoparadioxin (TCDD) and 1.1.1-trichloro-2-(2- chlorophenyl)-2-(4-chlorophenyl)ethane (o,p'DTT), are known to have steroidal actions as well as immunotoxic actions in animals and humans. These compounds bind to intracellular receptor proteins similar to those for glucocorticoids and estrogens. Since the immune system plays a crucial role in host resistance and homeostasis, the immunomodulation induced by the xenobiotics may be the basis for adversed health effects. Monocytes/macrophages have various key functions in initiating the immune regulation, mediating through antigen presentation, monokine production, and formation of arachidonate metabolites, and these functions are known to be affected by glucocorticoids and estrogens. In the projects proposed herein, we aim to investigate the molecular mechanism of actions of steroids and xenobiotics on function of monocytes/macrophages and subsequently, of cell mediated immunity.
The specific aims are to examine (a) whether these xenobiotics and steroids bind to the same or different receptors, (b) whether they induce or block the synthesis of second messenger proteins of steroids, (c) what are their actions on the gene expression of IL 1, TNF, HLA-DR and lipocortin and (d) whether these effects on IL 1, TNF, HLA-DR and lipocortin are attributed to alteration of arachidonate metabolism or of gene regulation by the xenobiotic- receptor complex or both. Xenobiotics and steroids will be incubated in vitro with fractionated human peripheral monocytes/macrophages in the absence and presence of specific and nonspecific activators such as gamma-lFN, LPS and phorbol esters. Metabolites of arachidonate will be quantitatively analyzed by high performance liquid chromatography. The binding analysis will be performed by competitive ligand binding assays. Identification of newly induced proteins will be carried out by two dimensional electrophoresis using (35S)methionine and their biological actions on monocytes and T lymphocytes will be examined. The regulation of IL 1, TNF, lipocortin (putative second messenger of glucocorticoids) and HLA-DR gene expression will be investigated by the Northern Blot using their cDNA clones as probes. To exploit not only the mechanism of immunotoxicity of xenobiotics but also the mechanism of immunoregulation leading to the immunosuppression (acquired immune deficiency), we propose to establish the mechanism of action of xenobiotics on the biochemical and cellular functions of monocytes/macrophages.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
1R01ES004802-01A1
Application #
3252919
Study Section
Toxicology Study Section (TOX)
Project Start
1989-02-01
Project End
1994-01-31
Budget Start
1989-02-01
Budget End
1990-01-31
Support Year
1
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Type
Schools of Public Health
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
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Uchida, Y; Jun, T; Ninomiya, H et al. (1996) Involvement of endothelins in immediate and late asthmatic responses of guinea pigs. J Pharmacol Exp Ther 277:1622-9
Sakamoto, T; Repasky, W T; Chen, J et al. (1995) Down-regulation of bcl-xs gene expression in rat thymocytes by dexamethasone. Biochem Biophys Res Commun 215:511-6
Hirata, F; Lee, J Y; Sakamoto, T et al. (1994) IL-1 beta regulates the expression of the Gi2 alpha gene via lipid mediators in guinea pig tracheal muscle. Biochem Biophys Res Commun 203:1889-96
Lee, J Y; Uchida, Y; Sakamoto, T et al. (1994) Alteration of G protein levels in antigen-challenged guinea pigs. J Pharmacol Exp Ther 271:1713-20
Wills-Karp, M; Uchida, Y; Lee, J Y et al. (1993) Organ culture with proinflammatory cytokines reproduces impairment of the beta-adrenoceptor-mediated relaxation in tracheas of a guinea pig antigen model. Am J Respir Cell Mol Biol 8:153-9
Uchida, Y; Ninomiya, H; Sakamoto, T et al. (1992) ET-1 released histamine from guinea pig pulmonary but not peritoneal mast cells. Biochem Biophys Res Commun 189:1196-201
Endo, T; Uchida, Y; Matsumoto, H et al. (1992) Regulation of endothelin-1 synthesis in cultured guinea pig airway epithelial cells by various cytokines. Biochem Biophys Res Commun 186:1594-9
Uchida, Y; Hamada, M; Kameyama, M et al. (1992) ET-1 induced bronchoconstriction in the early phase but not late phase of anesthetized dogs is inhibited by indomethacin and ICI 198615. Biochem Biophys Res Commun 183:1197-202
Ninomiya, H; Uchida, Y; Saotome, M et al. (1992) Endothelins constrict guinea pig tracheas by multiple mechanisms. J Pharmacol Exp Ther 262:570-6

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