Antioxidant Treatment of Thymic Organ Cultures Decreases NF-κ B and TCF1(α) Transcription Factor Activities and Inhibits α β T cell Development.
Using electrophoretic mobility shift assays (EMSA), we have recently shown that nuclear extracts of 14-day mouse fetal thymocytes contain abundant NF-κ B transcription factor activity. To determine the functional role of NF-κ B in early thymocyte development, we have exposed fetal thymus organ cultures to inhibitors of NF-κ B activation, namely the antioxidants N-acetyl-L-cysteine and butylated hydroxyanisole. Both compounds caused a dose-dependent arrest of thymocyte differentiation toward α β, but not γ δ, T cells. This was associated with a profound decrease in nuclear content of NF-κ B and TCF1(α) transcription factor activity, as determined by EMSA. In contrast, NF-Y was affected less strongly, and cyclic AMP-response-element-binding protein levels remained essentially unchanged by antioxidants. To test the idea that α β T cell development is correlated with NF-κ B and TCF1(α) activity, we conducted additional experiments in a submersion culture system in which the generation of α β T cells can be manipulated. Standard submersion culture supports gamma delta but α β T cell development. Under these conditions, EMSA showed that transcription factor activities were similar to those seen in the presence of antioxidants. Importantly, when the generation of α β T cells in submersion culture was restored by elevating oxygen concentrations, there was a dramatic increase in TCF1(α) activity, and both NF-κ B and NF-Y returned to control levels. Taken together, these results strongly suggest that NF-κ B and TCF1(α), presumably in concert with other transcription factors, play an important role in the development of α β T cells.
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- The Journal of Immunology
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- Academic Units
- Center for Radiological Research
- American Association of Immunologists
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- September 14, 2015