Antioxidant treatment of thymic organ cultures decreases NF-kappa B and TCF1(alpha) transcription factor activities and inhibits alpha beta 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-kappa B transcription factor activity. To determine the functional role of NF-kappa B in early thymocyte development, we have exposed fetal thymus organ cultures to inhibitors of NF-kappa B activation, namely the antioxidants N-acetyl-L-cysteine and butylated hydroxyanisole. Both compounds caused a dose-dependent arrest of thymocyte differentiation toward alpha beta, but not gamma delta, T cells. This was associated with a profound decrease in nuclear content of NF-kappa B and TCF1(alpha) 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 alpha beta T cell development is correlated with NF-kappa B and TCF1(alpha) activity, we conducted additional experiments in a submersion culture system in which the generation of alpha beta T cells can be manipulated. Standard submersion culture supports gamma delta but alpha beta 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 alpha beta T cells in submersion culture was restored by elevating oxygen concentrations, there was a dramatic increase in TCF1(alpha) activity, and both NF-kappa B and NF-Y returned to control levels. Taken together, these results strongly suggest that NF-kappa B and TCF1(alpha), presumably in concert with other transcription factors, play an important role in the development of alpha beta T cells.
Ivanov
V
V
INSERM Unité 184, Laboratoire de Génétique Moléculaire des Eucaryotes du CNRS, Faculté de Médecine, Strasbourg, France.
Merkenschlager
M
M
Ceredig
R
R
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D000975:Antioxidants / Q000494:pharmacology*; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000032:analysis*; D009924:Organ Culture Techniques; D011247:Pregnancy; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D014157:Transcription Factors / Q000032:analysis*
D015703:Antigens, CD; D000975:Antioxidants; D016328:NF-kappa B; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D014157:Transcription Factors; D000111:Acetylcysteine