Differential Proteomic Analyses of Cataracts From Rat Models of Type 1 and 2 Diabetes

Invest Ophthalmol Vis Sci. 2014 Nov 18;55(12):7848-61. doi: 10.1167/iovs.14-15175.

Abstract

Purpose: To identify differential changes in proteins and metabolites underlying "fast" type 1 (T1DC) and "slow" type 2 (T2DC) diabetic cataract (DC) formation in rat.

Methods: Rat models of types 1 and 2 diabetes consisted of streptozotocin injection without and with high-fat diet, respectively. Cataract progression was examined weekly. At week 6, total protein changes were comparatively and quantitatively assessed by two-dimensional differential in-gel electrophoresis (2-D DIGE) coupled with mass spectrometry, and relevant metabolic changes were examined. Differences in high molecular weight (HMW) crystallin species between diabetic and control lenses were similarly identified.

Results: Cataracts were morphologically different and progressed more slowly in T2DC versus T1DC. αA-crystallin, βB2-crystallin, and βA4-crystallin were significantly decreased in both DC types versus control. αB-crystallin was increased while βB1-crystallin was markedly decreased in T2DC. In T1DC, γB-crystallin and γS-crystallin fragmentation were increased. High-fat diet by itself had little impact, except for lowering γS-crystallin fragmentation. Despite significantly decreased opacity, a greater decrease in intermediate filaments (IFs) and more HMW crystallin species were observed in T2DC versus T1DC. However, aldose reductase expression and activity and sorbitol levels were increased to a greater extent in T1DC, while reduced glutathione (GSH) and reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) levels were decreased to a greater extent and adenosine triphosphate (ATP) level was much lower in T1DC versus T2DC.

Conclusions: The results suggest that osmotic damage, GSH loss, and decreased ATP production might be important pathological mechanisms in T1DC formation, whereas crystallin modification and cross-linking/aggregation as well as IF degradation may play more crucial roles in T2DC formation.

Keywords: 2-D DIGE; diabetic cataract; lens proteins; mass spectrometry; proteomics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Aldehyde Reductase / metabolism
  • Analysis of Variance
  • Animals
  • Cataract / metabolism*
  • Cataract / pathology
  • Diabetes Mellitus, Experimental / metabolism*
  • Diabetes Mellitus, Type 1 / metabolism*
  • Diabetes Mellitus, Type 2 / metabolism*
  • Disease Progression
  • Eye Proteins / metabolism*
  • Glutathione / metabolism
  • Lens, Crystalline / metabolism
  • Male
  • NADP / metabolism
  • Proteome
  • Rats
  • Rats, Wistar
  • Sorbitol / metabolism
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Substances

  • Eye Proteins
  • Proteome
  • Sorbitol
  • NADP
  • Adenosine Triphosphate
  • Aldehyde Reductase
  • Glutathione