The Transcription Factor NF-κB in Stem Cells and Development

NF-kappa B (nuclear factor kappa B) belongs to a family of transcription factors known to regulate a broad range of processes such as immune cell function, proliferation and cancer, neuroprotection, and long-term memory. Upcoming fields of NF-kappa B research include its role in stem cells and developmental processes. In the present review, we discuss one role of NF-kappa B in development in Drosophila, Xenopus, mice, and humans in accordance with the concept of evo-devo (evolutionary developmental biology). REL domain-containing proteins of the NF-kappa B family are evolutionarily conserved among these species. In addition, we summarize cellular phenotypes such as defective B- and T-cell compartments related to genetic NF-kappa B defects detected among different species. While NF-kappa B proteins are present in nearly all differentiated cell types, mouse and human embryonic stem cells do not contain NF-kappa B proteins, potentially due to miRNA-dependent inhibition. However, the mesodermal and neuroectodermal differentiation of mouse and human embryonic stem cells is hampered upon the repression of NF-kappa B. We further discuss NF-kappa B as a crucial regulator of differentiation in adult stem cells such as neural crest-derived and mesenchymal stem cells. In particular, c-REL seems to be important for neuronal differentiation and the neuroprotection of human adult stem cells, while RELA plays a crucial role in osteogenic and mesodermal differentiation.