Notch3 and canonical NF-kappaB signaling pathways cooperatively regulate Foxp3 transcription

• Published in: The Journal of immunology (1950) Vol. 186; no. 11; pp. 6199 - 6206
• Main Authors: Barbarulo, Alessandro, Grazioli, Paola, Campese, Antonio F, Bellavia, Diana, Di Mario, Giuseppina, Pelullo, Maria, Ciuffetta, Ambra, Colantoni, Sara, Vacca, Alessandra, Frati, Luigi, Gulino, Alberto, Felli, Maria Pia, Screpanti, Isabella
• Format: Journal Article
• Language: English
• Published: United States 01-06-2011
• Subjects: Animals; Cell Line; Cells, Cultured; Flow Cytometry; Forkhead Transcription Factors - genetics; Forkhead Transcription Factors - metabolism; Immunoblotting; Isoenzymes - genetics; Isoenzymes - metabolism; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; NF-kappa B - metabolism; Promoter Regions, Genetic - genetics; Protein Binding; Protein Kinase C - genetics; Protein Kinase C - metabolism; Protein Kinase C-theta; Receptor, Notch3; Receptors, Notch - genetics; Receptors, Notch - metabolism; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; T-Lymphocytes, Regulatory - metabolism; Thymus Gland - cytology; Thymus Gland - metabolism; Time Factors; Transcription Factor RelA - metabolism; Transcription, Genetic; Transcriptional Activation
• ISSN: 1550-6606
• DOI: 10.4049/jimmunol.1002136

Notch3 overexpression has been previously shown to positively regulate the generation and function of naturally occurring regulatory T cells and the expression of Foxp3, in cooperation with the pTα/pre-TCR pathway. In this study, we show that Notch3 triggers the trans activation of Foxp3 promoter depending on the T cell developmental stage. Moreover, we discovered a novel CSL/NF-κB overlapping binding site within the Foxp3 promoter, and we demonstrate that the activation of NF-κB, mainly represented by p65-dependent canonical pathway, plays a positive role in Notch3-dependent regulation of Foxp3 transcription. Accordingly, the deletion of protein kinase C, which mediates canonical NF-κB activation, markedly reduces regulatory T cell number and per cell Foxp3 expression in transgenic mice with a constitutive activation of Notch3 signaling. Collectively, our data indicate that the cooperation among Notch3, protein kinase C, and p65/NF-κB subunit modulates Foxp3 expression, adding new insights in the understanding of the molecular mechanisms involved in regulatory T cell homeostasis and function.