Regulation of Bcl-2 Protein Expression during Oxidative Stress in Neuronal and in Endothelial Cells

• Published in: Biochemical and biophysical research communications 1999-07, Vol.260 (2), p.522-526
• Main Authors: Longoni, Biancamaria, Boschi, Elena, Demontis, Gian Carlo, Marchiafava, Pier Lorenzo, Mosca, Franco
• Format: Article
• Language: English
• Subjects: Endothelium, Vascular - cytology; Endothelium, Vascular - metabolism; Enzyme-Linked Immunosorbent Assay; Humans; Microscopy, Fluorescence; Neurons - cytology; Neurons - metabolism; Oxidative Stress; Proto-Oncogene Proteins c-bcl-2 - metabolism; Retinal Rod Photoreceptor Cells - cytology; Retinal Rod Photoreceptor Cells - metabolism; Spectrometry, Fluorescence; Thiobarbituric Acid Reactive Substances - metabolism; Up-Regulation
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1999.0928

The relationship between oxidative stress and Bcl-2 expression was investigated in two different experimental models of oxidative stress. Acute oxidative stress was assessed by measuring, with fluorescence microscopy and cytofluorimetry, the increase in fluorescence of the oxidation-sensitive probe dihydrorhodamine 123, both in retinal rod receptor cells exposed to bright light (0.32 mW/cm2 for 15 minutes) and in human endothelial cells treated with the immunosuppressant cyclosporin A (200 μM for 21 h). In both cell types, acute oxidative stress reduced Bcl-2 expression and also caused a significant increase in the level of nucleosomes. Interestingly, chronic treatment with clinical concentrations of cyclosporin A (0.5–2.5 μM for 8 days) led to a significant increase in Bcl-2 expression, while nucleosomes were similar to control level. This suggests that up-regulation of Bcl-2 protein by low levels of oxidants may represent a critical factor in cellular adaptation to drug toxicity.