Spectrum and range of oxidative stress responses of human lens epithelial cells to H₂O₂ insult

PURPOSE. Oxidative stress (OS) is believed to be a major contributor to age-related cataract and other age-related diseases. METHODS. cDNA microarrays were used to identify the spectrum and range of genes with transcript levels that are altered in response to acute H₂O₂-induced OS in human lens epithelial (HLE) cells. HLE cells were treated with 50 μM H₂O₂ for 1 hour in the absence of serum, followed by a return to complete medium. RNAs were prepared from treated and untreated cells at 0, 1, 2, and 8 hours after H₂O₂ treatment. RESULTS. The data showed 1171 genes that were significantly up- and downregulated in response to H₂O₂ treatment. Several functional subcategories of genes were identified, including those encoding DNA repair proteins, antioxidant defense enzymes, molecular chaperones, protein biosynthesis enzymes, and trafficking and degradation proteins. Differential expression of selected genes was confirmed at the level of RNA and/or protein. Many of the identified genes (e.g., glutathione S-transferase [MGST2], thioredoxin reductase β, and peroxiredoxin 2) have been identified as participants in OS responses in the lens and other systems. Some genes induced by OS in the current study (e.g., oxygen regulated protein [ORP150] and heat shock protein [HSP40]) are better known to respond to other forms of stress. Two genes (receptor tyrosine kinase [AXL/ARK] and protein phosphatase 2A) are known to be differentially expressed in cataract. Most of the genes point to a novel pathways associated with OS. CONCLUSIONS. The present data provide a global perspective on those genes that respond to acute OS, point to novel genes and pathways associated with OS, and set the groundwork for understanding the functions of OS-related genes in lens protection and disease.