Purchase this article with an account.
P. Atmaca–Sonmez, X. Yang, J. Cai, M.A. Eskan, E.S. Yolcu, G. Tezel; Proteomic Identification of Glycated Proteins Shared by Ocular Hypertensive and Diabetic Rat Retinas . Invest. Ophthalmol. Vis. Sci. 2006;47(13):197.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Based on the evidence of an accelerated accumulation of advanced glycation end–products in glaucomatous retinas (as well as in diabetes) and the evidence of RGC apoptosis in diabetic eyes (which is characteristic of glaucoma), glycated retinal proteins were comparatively studied in rats with chronically induced IOP elevation or diabetes.
IOP elevation was induced by hypertonic saline injections into episcleral veins; and diabetes was induced by intraperitoneal injections of streptozosin. During an experimental period of up to 12 weeks, glycated retinal proteins were detected by Pro–Q Emerald 300 glycoprotein staining of 2D–gels followed by Sypro Ruby staining for total protein profiling. The proteins revealed by the specific staining were identified using mass spectrometry; and morphological techniques were utilized for further validation of the proteomic findings.
The number and intensity of protein spots exhibiting glycation were greater in diabetic retinas compared with the controls (p<0.01). In contrast to controls, protein glycation was also detectable in ocular hypertensive retinas at over 20 spots shared with diabetic retinas. Cytoskeletal proteins, including alpha–actin and beta–tubulin, as well as some glycolytic enzymes and signaling molecules, were identified from these spots with significant matches through peptide mass fingerprinting (p<0.05; sequence coverage 18–84%) and peptide sequencing using tandem mass spectrometry (sequence matches for multiple peptides). Despite widespread cellular localization of these proteins in retinal neurons and glia, electron microscopic findings were consistent with cytoskeletal alterations prominent in neurons of the ocular hypertensive and diabetic retinas, both including RGCs.
This in vivo study reveals protein glycation in ocular hypertensive as well as diabetic retinas, and identifies common targets of this protein modification in two different disease models. Glycation–associated structural and/or functional alterations in cytoskeletal integrity may be a common feature associated with increased susceptibility of RGCs to damage in both glaucoma and diabetes. Alternatively, protein dysfunction associated with glycation, which has also synergism with oxidative stress, may lead to diminished glial support thereby being another common factor facilitating the neuronal damage in both ocular hypertensive and diabetic retinas.
This PDF is available to Subscribers Only