Caspase-9 activation in hypoxic human corneal epithelial cells
| Autor: | Michelle Kurpakus-Wheater, Gabriel Sosne, Linda K. Mrock, M. L. McDermott, R. Sexton |
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| Rok vydání: | 2004 |
| Předmět: |
Cancer Research
Clinical Biochemistry Pharmaceutical Science Apoptosis Fas ligand Cornea Western blot medicine Humans Hypoxia Caspase Corneal epithelium Pharmacology Messenger RNA Caspase 8 biology medicine.diagnostic_test Biochemistry (medical) Epithelial Cells Cell Biology Fas receptor Molecular biology Caspase 9 medicine.anatomical_structure Caspases biology.protein Tumor necrosis factor alpha |
| Zdroj: | Apoptosis : an international journal on programmed cell death. 8(6) |
| ISSN: | 1360-8185 |
| Popis: | The purpose of this study was to determine the effect of hypoxia on caspase-8 and -9 gene and protein expression and activity in corneal epithelium. Non-transformed human corneal epithelial cells (HCEC) were cultured in 2% oxygen. A cDNA expression array coupled with densitometric analysis was used to compare relative mRNA expression levels of 96 apoptosis-related genes in hypoxic and normoxic HCEC. Caspase-8, caspase-9, FLIP, Fas, FasL, and TNFalpha protein expression was assessed further using Western blot analysis and ELISA. Caspase-8 and -9 activities were measured using a fluorometric activity assay. Hypoxia did not affect caspase-8 or -9 gene or protein expression in HCEC, however caspase-9 activity was significantly increased. Hypoxia significantly suppressed the activity of caspase-8. FLIP and Fas gene and protein expression were not significantly altered in hypoxic cells compared to normoxic controls. mRNA and protein levels of TNFalpha and TNFR-1 were significantly decreased, while FasL mRNA and proteins levels were significantly increased in hypoxic HCEC. In corneal epithelium stressed by hypoxia caspase-9 activity is upregulated, suggesting that apoptosis proceeds via the mitochondrial pathway. Caspase-8 activity may be suppressed because the loss of TNFalpha and TNFR-1 gene and protein expression inhibits the initial formation of a death signaling complex. |
| Databáze: | OpenAIRE |
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