Studies in this proposal are important because cataracts are the 3rd leading cause of blindness in man in the United States. However, the biochemical mechanism for most cataracts is unknown. Studies in this proposal are designed to elucidate underlying biochemical mechanisms for cataract formation. This will be accomplished by use of an extremely convenient animal model of cataract, the selenite overdose cataract. The long-term objective of this proposal is to provide a biochemical mechanism for selenium-induced cataract. Severe nuclear cataracts are produced in only 4 days by a single injection of an overdose of the essential trace mineral selenium (as sodium selenite) into young rats. The specific hypothesis to be tested is that selenite cataracts are caused by initial attack of selenite on lens epithelium, leading to calcium influx, activation of proteolysis, and insolubilization of lens proteins. Experimental set I (Proteolysis) will study the origin of insoluble polypeptides in selenite cataract, involvement of proteolytic enzymes and lens protein insolubilization processes. Experimental set II (Calcium) will study association of free calcium with localized opacities, permeability of lens to calcium, integrity of calcium and sodium pumps. Experimental set III (Epithelium) will study effect of selenite on cultured epithelium, and the role of the epithelium in development of the newly characterized selenite cortical cataract. These studies will provide a clear-cut biochemical mechanism for selenite cataractogenesis. Hopefully, such knowledge would indicate avenues leading to prevention and treatment of cataract in man.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY003600-07
Application #
3257965
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1981-09-30
Project End
1992-11-30
Budget Start
1987-12-01
Budget End
1988-11-30
Support Year
7
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Oregon Health and Science University
Department
Type
Schools of Dentistry/Oral Hygn
DUNS #
009584210
City
Portland
State
OR
Country
United States
Zip Code
97239
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Kim, Yung Hae; Kapfer, Deborah M; Boekhorst, Jos et al. (2002) Deamidation, but not truncation, decreases the urea stability of a lens structural protein, betaB1-crystallin. Biochemistry 41:14076-84
Lampi, Kirsten J; Shih, Marjorie; Ueda, Yoji et al. (2002) Lens proteomics: analysis of rat crystallin sequences and two-dimensional electrophoresis map. Invest Ophthalmol Vis Sci 43:216-24
Nakajima, Takeshi; Nakajima, Emi; Fukiage, Chiho et al. (2002) Differential gene expression in the lens epithelial cells from selenite injected rats. Exp Eye Res 74:231-6
Lampi, Kirsten J; Kim, Yung H; Bachinger, Hans Peter et al. (2002) Decreased heat stability and increased chaperone requirement of modified human betaB1-crystallins. Mol Vis 8:359-66
Tamada, Y; Fukiage, C; Mizutani, K et al. (2001) Calpain inhibitor, SJA6017, reduces the rate of formation of selenite cataract in rats. Curr Eye Res 22:280-5
Shih, M; David, L L; Lampi, K J et al. (2001) Proteolysis by m-calpain enhances in vitro light scattering by crystallins from human and bovine lenses. Curr Eye Res 22:458-69
Nakamura, Y; Fukiage, C; Azuma, M et al. (2001) Calpain-induced light scattering in young rat lenses is enhanced by UV-B. J Ocul Pharmacol Ther 17:47-58
Lampi, K J; Oxford, J T; Bachinger, H P et al. (2001) Deamidation of human beta B1 alters the elongated structure of the dimer. Exp Eye Res 72:279-88
Nakamura, Y; Fukiage, C; Shih, M et al. (2000) Contribution of calpain Lp82-induced proteolysis to experimental cataractogenesis in mice. Invest Ophthalmol Vis Sci 41:1460-6

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