Folates are required for DNA synthesis, cell regeneration, and methionine metabolism. Folate deficiency results in anemia, functional abnormalities of the small intestine, and hyperhomocysteinemia with increased risk of vascular disease. This application proposes a systematic study of the membrane proteins that may regulate folate absorption in the intestine and folate uptake by the liver and the proximal renal tubule of the pig and their single and synergistic perturbations by folate deficiency and chronic alcohol consumption.
The specific aims are: 1) to establish the molecular sequences, tissue expression, and kinetics of three folate regulatory proteins: jejunal brush border folate polyglutamate hydrolase (BBFH) and the liver and kidney membrane folate binding protein (FBP) and reduced folate carrier (RFC); 2) to use human tissues to evaluate the relevance of the pig as a model for human folate homeostasis; and 3) evaluate perturbations of these proteins by combinations of folate deficiency and chronic alcohol consumption in micropigs. The distribution of folate coenzyme forms will be determine in liver, kidney, and intestinal mucosa and in urine. The PI will isolate full length clones for the BBFH and RFC from intestine from pig and humans. Antibodies to the expressed proteins will be obtained. The cDNA's and antibodies will be used to study the effect of alcohol and folate deficiency on transcription and expression of these proteins. Isolated membrane vesicles will be used to study fatty acid composition and for functional studies of folate binding and transport in normal, folate deficient, and folate deficient alcoholic pigs. The studies are expected to form a basis for future studies on gene regulation of each of the membrane proteins and on a molecular understanding of the pathogenesis of folate deficiency in intestinal diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK045301-07
Application #
6176523
Study Section
Nutrition Study Section (NTN)
Program Officer
May, Michael K
Project Start
1992-09-30
Project End
2002-06-30
Budget Start
2000-07-01
Budget End
2002-06-30
Support Year
7
Fiscal Year
2000
Total Cost
$264,491
Indirect Cost
Name
University of California Davis
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
Halsted, Charles H; Villanueva, Jesus A; Devlin, Angela M et al. (2002) Folate deficiency disturbs hepatic methionine metabolism and promotes liver injury in the ethanol-fed micropig. Proc Natl Acad Sci U S A 99:10072-7
Halsted, Charles H; Villanueva, Jesus A; Devlin, Angela M (2002) Folate deficiency, methionine metabolism, and alcoholic liver disease. Alcohol 27:169-72
Halsted, Charles H; Villanueva, Jesus A; Devlin, Angela M et al. (2002) Interactions of ethanol and folate deficiency in development of alcoholic liver disease in the micropig. Trans Am Clin Climatol Assoc 113:151-62; discussion 162-3
Villanueva, J A; Devlin, A M; Halsted, C H (2001) Reduced folate carrier: tissue distribution and effects of chronic ethanol intake in the micropig. Alcohol Clin Exp Res 25:415-20
Devlin, A M; Ling, E H; Peerson, J M et al. (2000) Glutamate carboxypeptidase II: a polymorphism associated with lower levels of serum folate and hyperhomocysteinemia. Hum Mol Genet 9:2837-44
Halsted, C H; Ling, E H; Luthi-Carter, R et al. (1998) Folylpoly-gamma-glutamate carboxypeptidase from pig jejunum. Molecular characterization and relation to glutamate carboxypeptidase II. J Biol Chem 273:20417-24
Villanueva, J; Ling, E H; Chandler, C J et al. (1998) Membrane and tissue distribution of folate binding protein in pig. Am J Physiol 275:R1503-10
Van Hoozen, C M; Ling, E H; Halsted, C H (1996) Folate binding protein: molecular characterization and transcript distribution in pig liver, kidney and jejunum. Biochem J 319 ( Pt 3):725-9