Toxicity and detoxification of lipid-derived aldehydes in cultured retinal pigmented epithelial cells

S. Choudhary, T. Xiao, S. Srivastava, W. Zhang, L. L. Chan, L. A. Vergara, F. J.G.M. Van Kuijk, N. H. Ansari

Research output: Contribution to journalArticlepeer-review

88 Scopus citations


Age-related macular degeneration (ARMD) is the leading cause of blindness in the developed world and yet its pathogenesis remains poorly understood. Retina has high levels of polyunsaturated fatty acids (PUFAs) and functions under conditions of oxidative stress. To investigate whether peroxidative products of PUFAs induce apoptosis in retinal pigmented epithelial (RPE) cells and possibly contribute to ARMD, human retinal pigmented epithelial cells (ARPE-19) were exposed to micromolar concentrations of H2O 2, 4-hydroxynonenal (HNE) and 4-hydroxyhexenal (HHE). A concentration- and time-dependent increase in H2O2-, HNE-, and HHE-induced apoptosis was observed when monitored by quantifying DNA fragmentation as determined by ELISA, flow cytometry, and Hoechst staining. The broad-spectrum inhibitor of apoptosis Z-VAD inhibited apoptosis. Treatment of RPE cells with a thionein peptide prior to exposure to H2O 2 or HNE reduced the formation of protein-HNE adducts as well as alteration in mitochondrial membrane potential and apoptosis. Using 3H-HNE, various metabolic pathways to detoxify HNE by ARPE-19 cells were studied. The metabolites were separated by HPLC and characterized by ElectroSpray Ionization-Mass Spectrometry (ESI-MS) and gas chromatography-MS. Three main metabolic routes of HNE detoxification were detected: (1) conjugation with glutathione (GSH) to form GS-HNE, catalyzed by glutathione-S-transferase (GST), (2) reduction of GS-HNE catalyzed by aldose reductase, and (3) oxidation of HNE catalyzed by aldehyde dehydrogenase (ALDH). Preventing HNE formation by a combined strategy of antioxidants, scavenging HNE by thionein peptide, and inhibiting apoptosis by caspase inhibitors may offer a potential therapy to limit retinal degeneration in ARMD.

Original languageEnglish (US)
Pages (from-to)122-134
Number of pages13
JournalToxicology and Applied Pharmacology
Issue number2
StatePublished - Apr 15 2005


  • 4-Hydroxyhexenal
  • 4-Hydroxynonenal
  • Age-related macular degeneration
  • Apoptosis
  • Epithelium
  • Oxidative stress
  • Retinal pigmented

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology


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