The objective of the proposed studies is to continue studies on understanding the biochemical mechanism(s) responsible for maintaining the clarity of the lens and those that lead to the formation of senile and diabetic cataracts. A reliable, reproducible, and sensitive digital image analysis method will be developed to quantitate the alterations in transmitted light during cataractogenesis. A fluorometric variant of this technique will be used for the determination of lens constituents such as free intracellular calcium, and sodium, lipid peroxides and also for the measurement of intracellular pH and transmembrane voltage. In addition, a single lens fiber cell model for studying cataractogenesis will also be developed. The proposed studies are aimed at understanding the contribution of polyol pathway, nonenzymatic glycosylation and perturbed redox state to cataractogenesis induced by hyperglycemia and oxidative stress generated by free radicals and sulfhydryl oxidation. The role of free intracellular calcium, increased proteolysis and changes in the redox state of the lens leading to alterations in NAD(P)H/NAD(P) and GSH/GSSG ratio will be investigated. The mechanism of activation of lens aldose reductase by glycosylation and oxidation will also be studied and the amino acid residues modified will be identified. Furthermore, the proteolytic susceptibility of crystallins modified by oxidative stress and/or nonenzymatic glycosylation will be investigated. Studies on the mechanism of transport of electrophilic xenobiotics and oxidized glutathione and the interrelationship between the two transport systems will demonstrate the role of the transport of oxidized glutathione and glutathione-xenobiotic in determining the redox state of the lens, and show how electrophilic xenobiotics affect GSSG levels and how increased oxidative stress affects detoxification of xenobiotics. These studies will identify the role of oxidative stress and non-enzymatic glycosylation in protein modification, proteolysis, and crystallin aggregation and will quantitatively elucidate the mechanisms by which intracellular ionic changes contribute to cataractogenesis.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY001677-24
Application #
6125162
Study Section
Visual Sciences A Study Section (VISA)
Program Officer
Liberman, Ellen S
Project Start
1978-06-01
Project End
2001-11-30
Budget Start
1999-12-01
Budget End
2000-11-30
Support Year
24
Fiscal Year
2000
Total Cost
$252,110
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Biochemistry
Type
Schools of Medicine
DUNS #
041367053
City
Galveston
State
TX
Country
United States
Zip Code
77555
Ramana, Kota V; Bhatnagar, Aruni; Srivastava, Sanjay et al. (2006) Mitogenic responses of vascular smooth muscle cells to lipid peroxidation-derived aldehyde 4-hydroxy-trans-2-nonenal (HNE): role of aldose reductase-catalyzed reduction of the HNE-glutathione conjugates in regulating cell growth. J Biol Chem 281:17652-60
Pladzyk, Agnieszka; Ramana, Kota V; Ansari, Naseem H et al. (2006) Aldose reductase prevents aldehyde toxicity in cultured human lens epithelial cells. Exp Eye Res 83:408-16
Pladzyk, Agnieszka; Reddy, Aramati B M; Yadav, Umesh C S et al. (2006) Inhibition of aldose reductase prevents lipopolysaccharide-induced inflammatory response in human lens epithelial cells. Invest Ophthalmol Vis Sci 47:5395-403
Singh, Ranvir; White, Mark A; Ramana, Kota V et al. (2006) Structure of a glutathione conjugate bound to the active site of aldose reductase. Proteins 64:101-10
Ramana, Kota V; Willis, Monte S; White, Michael D et al. (2006) Endotoxin-induced cardiomyopathy and systemic inflammation in mice is prevented by aldose reductase inhibition. Circulation 114:1838-46
Srivastava, Satish K; Ramana, Kota V; Bhatnagar, Aruni (2005) Role of aldose reductase and oxidative damage in diabetes and the consequent potential for therapeutic options. Endocr Rev 26:380-92
Ramana, Kota V; Friedrich, Brian; Tammali, Ravinder et al. (2005) Requirement of aldose reductase for the hyperglycemic activation of protein kinase C and formation of diacylglycerol in vascular smooth muscle cells. Diabetes 54:818-29
Srivastava, Seema; Tammali, Ravinder; Chandra, Deepak et al. (2005) Regulation of lens aldose reductase activity by nitric oxide. Exp Eye Res 81:664-72
Ramana, Kota V; Bhatnagar, Aruni; Srivastava, Satish K (2004) Aldose reductase regulates TNF-alpha-induced cell signaling and apoptosis in vascular endothelial cells. FEBS Lett 570:189-94
Ramana, Kota V; Bhatnagar, Aruni; Srivastava, Satish K (2004) Inhibition of aldose reductase attenuates TNF-alpha-induced expression of adhesion molecules in endothelial cells. FASEB J 18:1209-18

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