Inhibition of methylglyoxal-mediated protein modification in glyoxalase I overexpressing mouse lenses.
Objective. Here we tested the role of Glo I in the prevention of advanced glycation end product (AGE) formation in transgenic mouse lenses. Methods. A transgenic animal line that expressed high levels of human Glo I in the lens was developed from the C57B6 mouse strain. The role of Glo I in the inhibition of MGO-AGE formation was tested in organ-cultured lenses. Results. Organ culture of Wt and Glo I lenses with 5 mM D, L-glyceraldehyde (GLD) enhanced MGO by 29-fold and 17-fold in Wt lenses and Glo I lenses, respectively. Argpyrimidine levels were 192 +/- 73 pmoles/mg protein, and hydroimidazolone levels were 22 +/- 0.7 units/mug protein in GLD-incubated Wt lenses. In Glo I lenses, formation of AGEs was significantly inhibited; the argpyrimidine levels were 82 +/- 18 pmoles/mg protein, and the HI levels were 2.6 +/- 2.3 units/mug protein. Incubation of Wt lens proteins with 5 mM ribose for 7 days resulted in the formation of pentosidine. However, the levels were substantially higher in Glo I lens proteins incubated with ribose. Conclusion. Our study provides direct evidence that Glo I activity plays an important role in the regulation of AGE synthesis in the lens; while Glo I activity blocks the formation of MGO-AGEs, it might promote the formation of sugar-derived AGEs.
Gangadhariah
Mahesha H
MH
Department of Ophthalmology & Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
Mailankot
Maneesh
M
Reneker
Lixing
L
Nagaraj
Ram H
RH