Two major groups of molecules are sulfated in the body; small molecules such as drugs, hormones and environmental chemicals, as well as large molecules such as proteins and glycosaminoglycans. The sulfate conjugation reaction is catalyzed by sulfotransferases utilizing adenosine 3' -phosphate 5' -phosphosulfate (PAPS) as the sulfate donor. Brachymorphic mice have a defect in PAPS synthesis, and thus undersulfate glycosaminoglycans which results in joint and skeletal defects. The sulfation of xenobiotics is characterized as being a high-affinity, how- capacity pathway. The low-capacity sulfation of xenobiotics in rats is due to a limited availability of PAPS, which in turn is limited by the availability of sulfate. Molybdate also decreases hepatic levels of PAPS and sulfate. Molybdenum is known to produce joint problems, which can be prevented by sulfate and methionine. Because joints are largely cartilage and a major constituent of cartilage is sulfated glycosaminoglycans, we propose to test the hypothesis that joint problems produced by molybdate are due to an undersulfation of the glycosaminoglycans. There is also evidence in the literature that drugs that are sulfated decrease the sulfation of glycosaminoglycans and produce teratological effects in the cartilage-skeletal system.
Six specific aims will be addressed in the proposed research. We plan to test the hypotheses that: (1) PAPS concentrations can be decreased by molybdate, (2) PAPS depletion by molybdate is a useful tool for determining the importance of sulfation in toxicology, (3) molybdate interferes with glycosaminoglycan sulfation, (4) chlorinated phenols inhibit glycosaminoglycan synthesis by inhibiting sulfation, (5) chemicals that are sulfated decrease glycosaminoglycan sulfation, (6) and chemical interference of glycosaminoglycan sulfation is not unique to rats. Methods to be employed are enzymatic quantitation of PAPS, HPLC- ion chromatographic analysis of sulfate and use of isotopes to quantitate glycosaminoglycan synthesis. Scientifically these investigations are intriguing because they may reveal novel mechanisms for toxic effects of chemicals via impairment of the sulfation of glycosaminoglycans. They are also of potential medical significance, because sulfation of the glycosaminoglycans in cartilage is essential for the proper functioning of joints, and joint ailments are the number one cause of debilitation in the aging American population. Therefore, the long-term goal of these studies is to determine if and how chemicals interfere with cartilage formation and thus joint disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES003192-23
Application #
2153253
Study Section
Toxicology Subcommittee 2 (TOX)
Project Start
1983-08-01
Project End
1997-11-30
Budget Start
1994-12-01
Budget End
1995-11-30
Support Year
23
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of Kansas
Department
Pharmacology
Type
Schools of Medicine
DUNS #
016060860
City
Kansas City
State
KS
Country
United States
Zip Code
66160
Klaassen, Curtis D; Reisman, Scott A (2010) Nrf2 the rescue: effects of the antioxidative/electrophilic response on the liver. Toxicol Appl Pharmacol 244:57-65
Shelby, M K; Klaassen, C D (2006) Induction of rat UDP-glucuronosyltransferases in liver and duodenum by microsomal enzyme inducers that activate various transcriptional pathways. Drug Metab Dispos 34:1772-8
Cherrington, Nathan J; Slitt, Angela L; Li, Ning et al. (2004) Lipopolysaccharide-mediated regulation of hepatic transporter mRNA levels in rats. Drug Metab Dispos 32:734-41
Shelby, M K; Cherrington, N J; Vansell, N R et al. (2003) Tissue mRNA expression of the rat UDP-glucuronosyltransferase gene family. Drug Metab Dispos 31:326-33
Cherrington, Nathan J; Slitt, Angela L; Maher, Jonathan M et al. (2003) Induction of multidrug resistance protein 3 (mrp3) in vivo is independent of constitutive androstane receptor. Drug Metab Dispos 31:1315-9
Guo, Grace L; Johnson, David R; Klaassen, Curtis D (2002) Postnatal expression and induction by pregnenolone-16alpha-carbonitrile of the organic anion-transporting polypeptide 2 in rat liver. Drug Metab Dispos 30:283-8
Guo, Grace L; Choudhuri, Supratim; Klaassen, Curtis D (2002) Induction profile of rat organic anion transporting polypeptide 2 (oatp2) by prototypical drug-metabolizing enzyme inducers that activate gene expression through ligand-activated transcription factor pathways. J Pharmacol Exp Ther 300:206-12
Johnson, David R; Habeebu, Sultan S M; Klaassen, Curtis D (2002) Increase in bile flow and biliary excretion of glutathione-derived sulfhydryls in rats by drug-metabolizing enzyme inducers is mediated by multidrug resistance protein 2. Toxicol Sci 66:16-26
Johnson, David R; Guo, Grace L; Klaassen, Curtis D (2002) Expression of rat Multidrug Resistance Protein 2 (Mrp2) in male and female rats during normal and pregnenolone-16alpha-carbonitrile (PCN)-induced postnatal ontogeny. Toxicology 178:209-19
Brady, James M; Cherrington, Nathan J; Hartley, Dylan P et al. (2002) Tissue distribution and chemical induction of multiple drug resistance genes in rats. Drug Metab Dispos 30:838-44

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