Oxidized low density lipoproteins induce a pathologic response by retinal pigmented epithelial cells.

Abstract

The accumulation of apolipoprotein B100 lipoproteins in Bruch membrane is an early event thought to promote age-related macular degeneration (AMD). Immunohistochemistry using an anti-oxidized low density lipoprotein antibody on 10 AMD specimens showed staining in Bruch membrane including basal deposits, a marker of AMD. To determine whether retinal pigmented epithelial cells develop a pathologic phenotype after interaction with lipoproteins, ARPE-19 cells were exposed to low density lipoproteins (LDL) or oxidized LDLs (oxLDL). Analysis using the Affymetrix U133 Plus 2.0 (Affymetrix, Inc., Santa Clara, CA, USA) gene chip showed physiological and pathological transcriptional responses after LDL and oxLDL treatment, respectively. LDL induced a down-regulation of cholesterol biosynthesis genes while oxLDL induced transcriptional alterations in genes related to lipid metabolism, oxidative stress, inflammation and apoptosis. Electrospray mass spectrometry showed that oxLDL, but not LDL induced large cellular increases of sphingomyelin, ceramides, and cholesteryl esters. With TUNEL labeling, oxLDL caused 14.6% apoptosis compared to <1% after LDL. Addition of an inhibitor of sphingomyelin synthase inhibited this apoptosis by 41%. These data support the hypothesis that oxidized lipoproteins are one trigger for initiating early events in the pathogenesis of AMD.

• Authors: Yuko Yamada, Jane Tian, Yanqin Yang, Roy G Cutler, Tinghuai Wu, Richard S Telljohann, Mark P Mattson, James T Handa
• Journal: Journal of neurochemistry (J Neurochem) Vol. 105 Issue 4 Pg. 1187-97 (May 2008) ISSN: 1471-4159 [Electronic] England
• PMID: 18182060 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Lipoproteins, LDL
• oxidized low density lipoprotein

Topics

• Adult
• Aged
• Aged, 80 and over
• Apoptosis (physiology)
• Cell Line, Transformed
• Female
• Humans
• Lipid Peroxidation (physiology)
• Lipoproteins, LDL (metabolism, physiology)
• Macular Degeneration (etiology, metabolism, pathology)
• Male
• Middle Aged
• Pigment Epithelium of Eye (metabolism, pathology)