The overall objective of this proposal is to define the biochemical basis and mechanisms of crystallin pigmentation and crosslinking in lens aging and cataractogenesis. Progress achieved in the past 2 1/2 years in the applicant's laboratory unraveled a high correlation between lens pigmentation and pentosidine, an ascorbate-derived protein crosslink formed in a Maillard-type reaction. This and other observations strongly implicate toxicity of ascorbate oxidation products in lens senescence and cataractogenesis. We propose to investigate the mechanism(s) by which ascorbate turns into a Maillard reactant and the extent to which the ascorbate mediated Maillard reaction explains human lens crystallin pigmentation and crosslinking in aging and cataractogenesis. Specifically, we hypothesize that several lines of defense must be weakened before ascorbate mediates lens crystallin pigmentation and crosslinking by the Maillard reaction. In order to clarify the nature of the biochemical defect the following experiments will be performed: 1. We will first identify differences in patterns of ascorbate degradation products in young, old and cataractous human lenses and elucidate the structure of these products. 2. We will identify specific human lens fractions that contain inhibitory activity against the ascorbate mediated Maillard reaction and characterize the biochemical nature of the ascorbate degradation inhibitory activity(ies). 3. We will elucidate the structure of the advanced Maillard products specific for ascorbate, focusing especially on the structure of long-wave fluorescent molecules. 4. Finally, we will systematically correlate specific defects in ascorbate metabolism uncovered in specific aims I-III with extent of crystallin pigmentation and crosslinking and the presence of specific advanced Maillard reaction products as a function of age and presence of cataract. The successful completion of this project may result in generating clues for a novel hypothesis of cataractogenesis based on genetic defects in ascorbate metabolism in the lens.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY007099-07
Application #
3263994
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1987-08-01
Project End
1997-07-31
Budget Start
1993-08-01
Budget End
1994-07-31
Support Year
7
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Case Western Reserve University
Department
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Whitson, Jeremy A; Wilmarth, Phillip A; Klimek, John et al. (2017) Proteomic analysis of the glutathione-deficient LEGSKO mouse lens reveals activation of EMT signaling, loss of lens specific markers, and changes in stress response proteins. Free Radic Biol Med 113:84-96
Fan, Xingjun; Monnier, Vincent M; Whitson, Jeremy (2017) Lens glutathione homeostasis: Discrepancies and gaps in knowledge standing in the way of novel therapeutic approaches. Exp Eye Res 156:103-111
Feng, Weiyi; Rosca, Mariana; Fan, Yuxuan et al. (2017) Gclc deficiency in mouse CNS causes mitochondrial damage and neurodegeneration. Hum Mol Genet 26:1376-1390
Whitson, Jeremy A; Sell, David R; Goodman, Michael C et al. (2016) Evidence of Dual Mechanisms of Glutathione Uptake in the Rodent Lens: A Novel Role for Vitreous Humor in Lens Glutathione Homeostasis. Invest Ophthalmol Vis Sci 57:3914-25
Sell, David R; Sun, Wanjie; Gao, Xiaoyu et al. (2016) Skin collagen fluorophore LW-1 versus skin fluorescence as markers for the long-term progression of subclinical macrovascular disease in type 1 diabetes. Cardiovasc Diabetol 15:30
Fan, Xingjun; Zhou, Sheng; Wang, Benlian et al. (2015) Evidence of Highly Conserved ?-Crystallin Disulfidome that Can be Mimicked by In Vitro Oxidation in Age-related Human Cataract and Glutathione Depleted Mouse Lens. Mol Cell Proteomics 14:3211-23
Monnier, Vincent M; Sun, Wanjie; Sell, David R et al. (2014) Glucosepane: a poorly understood advanced glycation end product of growing importance for diabetes and its complications. Clin Chem Lab Med 52:21-32
Linetsky, Mikhail; Raghavan, Cibin T; Johar, Kaid et al. (2014) UVA light-excited kynurenines oxidize ascorbate and modify lens proteins through the formation of advanced glycation end products: implications for human lens aging and cataract formation. J Biol Chem 289:17111-23
Fessel, Gion; Li, Yufei; Diederich, Vincent et al. (2014) Advanced glycation end-products reduce collagen molecular sliding to affect collagen fibril damage mechanisms but not stiffness. PLoS One 9:e110948
Monnier, Vincent M; Sell, David R; Strauch, Christopher et al. (2013) The association between skin collagen glucosepane and past progression of microvascular and neuropathic complications in type 1 diabetes. J Diabetes Complications 27:141-9

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