title: Age-related macular degeneration and retinal protein modification by 4-hydroxy-2-nonenal.
abstract: OBJECTIVE
  Oxidative damage to proteins, lipids, and DNA has been suggested to be a mechanism for age-related macular degeneration (AMD). The retina is particularly susceptible to lipid peroxidation due to high concentrations of easily oxidized polyunsaturated fatty acids in the presence of abundant oxygen. One of the most toxic products of lipid peroxidation, 4-hydroxy-2-nonenal (HNE), can modify and inactivate proteins. The hypothesis was that 4-HNE-modified proteins would accumulate and serve as a marker for progressive stages of AMD.
  
  
  METHODS
  Proteins containing HNE adducts were identified in both the macular and peripheral regions during four progressive stages of AMD. The proteins were resolved by two-dimensional (2-D) gel electrophoresis before detection of HNE-adducted proteins. Modified proteins were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The total content of HNE adducts was compared using a slot blot immunoassay. One-dimensional Western blot analysis was used to measure levels of proteins involved in HNE detoxification.
  
  
  RESULTS
  Nineteen proteins that were consistently modified regardless of stage of AMD or retinal region were identified. These proteins are involved in two main functions: energy production and stress response. No change in total HNE-adducted protein was observed between regions or stages. Modest increases in content of proteins involved in HNE detoxification were observed.
  
  
  CONCLUSIONS
  Consistently modified proteins indicate preferred protein targets for oxidation by HNE. HNE-modified proteins were not different between regions or stages, suggesting that pathways for detoxification of HNE or removal of damaged proteins are adequate. Consistent levels of HNE-modified proteins suggest that HNE is not a sensitive retinal biomarker for AMD.
authors.affiliation: Department of Biochemistry, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Cheryl M
authors.initials: CM
authors.lastname: Ethen
authors.forename: Cavan
authors.initials: C
authors.lastname: Reilly
authors.forename: Xiao
authors.initials: X
authors.lastname: Feng
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Olsen
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Ferrington
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000447:Aldehydes / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism*; D015153:Blotting, Western; D018450:Disease Progression; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation; D008268:Macular Degeneration / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D051381:Rats; D011916:Rats, Inbred F344; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000447:Aldehydes; D015415:Biomarkers; C027576:4-hydroxy-2-nonenal