- In essential fatty acid (EFA) deficient epidermal skin disease, lack of the dietary essential fatty acids 18:2 and 20:4 (n-6) results in a hyperproliferative epidermis. Topical application of 18:2 (n-6) normalizes epidermal proliferation through an unknown mechanism. The hypothesis driving this proposal is that the fatty acid content of membrane phospholipids controls the viscosity (fluidity) of the cell membrane and that this parameter, in turn, affects membrane mechanisms that control cell function. The long-term objective of the proposed studies is to determine the mechanism of membrane phospholipid fatty acid regulation of keratinocyte function. In vitro EFA-deficient keratinocytes will be grown in EFA-supplemented medium to yield cells with """"""""normalized"""""""" membranes. For the EFA- deficient cells, the """"""""normalization"""""""" of their phospholipid fatty acid content and successful measurements of membrane viscosity have been reported by these investigators. Thus it is proposed to use this characterized keratinocyte culture in Electron Paramagnetic Resonance experiments, with concomitant High Performance Liquid Chromatography and Gas Chromatographic analysis and extensive data reductions to: A. Test the hypothesis that changes in membrane fluidity caused by altered phospholipid fatty acid content alter the kinetic rates of fatty acid metabolism. Cell membrane fluidity will be altered using the epidermal EFAs 18:2(n-6) and 20:4(n-6), and 22:6(n-3) which is not present in epidermis and is apparently metabolically inert; B. define the key determiners, in disease and therapy, of membrane viscosity (EPR) and fatty acid profile by adding to the growth medium various lipids and nutrients; C. analyze second messenger and signalling systems in EFA-deficient and fatty acid-normalized cells. Performance of the proposed studies, it is hoped, will identify mechanisms by which the membrane fluidity of the cells alters the activity of membrane-associated enzyme and signal transduction systems. It is ventured that understanding these basic mechanisms will expand our knowledge of epidermal function and diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
2R01AR026009-16A1
Application #
2396727
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1979-07-01
Project End
2002-06-30
Budget Start
1997-08-01
Budget End
1998-06-30
Support Year
16
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Surgery
Type
Schools of Medicine
DUNS #
791277940
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Hee Chung, S; Terashi, H; Rhodes, L M et al. (2001) The effect of three Korean traditional medicines on the growth rate of cultured human keratinocytes. J Ethnopharmacol 74:53-61
Marcelo, C L; Dunham, W R (1997) Retinoic acid stimulates essential fatty acid-supplemented human keratinocytes in culture. J Invest Dermatol 108:758-62
Fulbright, R M; Axelrod, D; Dunham, W R et al. (1997) Fatty acid alteration and the lateral diffusion of lipids in the plasma membrane of keratinocytes. Exp Cell Res 233:128-34
Dunham, W R; Klein, S B; Rhodes, L M et al. (1996) Oleic acid and linoleic acid are the major determinants of changes in keratinocyte plasma membrane viscosity. J Invest Dermatol 107:332-5
Garner, W L; Oyatsu, Y; Zuccaro, C et al. (1995) The effect of essential fatty acid supplementation on keratinocyte replication. Prostaglandins Leukot Essent Fatty Acids 52:349-55
Marcelo, C L; Rhodes, L M; Dunham, W R (1994) Normalization of essential-fatty-acid-deficient keratinocytes requires palmitic acid. J Invest Dermatol 103:564-8
Marcelo, C L; Dunham, W R (1993) Fatty acid metabolism studies of human epidermal cell cultures. J Lipid Res 34:2077-90
Marcelo, C L; Duell, E A; Rhodes, L M et al. (1992) In vitro model of essential fatty acid deficiency. J Invest Dermatol 99:703-8
Hadley, G A; Marcelo, C L; Steinmuller, D (1988) Monoclonal antibodies to tissue-restricted autoantigens in the mouse epidermis. Hybridoma 7:441-51