title: Elevated IKKα accelerates the differentiation of human neuronal progenitor cells and induces MeCP2-dependent BDNF expression.
abstract: The IκB kinase α (IKKα) is implicated in the differentiation of epithelial and immune cells. We examined whether IKKα also plays a role in the differentiation and maturation of embryonic human neuronal progenitor cells (NPCs). We find that expression of an extra copy of IKKα (IKKα+) blocks self-renewal and accelerates the differentiation of NPCs. This coincides with reduced expression of the Repressor Element Silencing Transcription Factor/Neuron-Restrictive Silencing Factor (REST/NRSF), which is a prominent inhibitor of neurogenesis, and subsequent induction of the pro-differentiation non-coding RNA, miR-124a. However, the effects of IKKα on REST/NRSF and miR-124a expression are likely to be indirect. IKKα+ neurons display extensive neurite outgrowth and accumulate protein markers of neuronal maturation such as SCG10/stathmin-2, postsynaptic density 95 (PSD95), syntaxin, and methyl-CpG binding protein 2 (MeCP2). Interestingly, IKKα associates with MeCP2 in the nuclei of human neurons and can phosphorylate MeCP2 in vitro. Using chromatin immunoprecipitation assays, we find that IKKα is recruited to the exon-IV brain-derived neurotrophic factor (BDNF) promoter, which is a well-characterized target of MeCP2 activity. Moreover, IKKα induces the transcription of BDNF and knockdown expression of MeCP2 interferes with this event. These studies highlight a role for IKKα in accelerating the differentiation of human NPCs and identify IKKα as a potential regulator of MeCP2 function and BDNF expression.
authors: Biology Division 216-76, California Institute of Technology, Pasadena, California, United States of America. khoshnan@caltech.edu
authors: Ali
authors: A
authors: Khoshnan
authors: Paul H
authors: PH
authors: Patterson
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism*; D051783:Methyl-CpG-Binding Protein 2 / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D058953:Neural Stem Cells / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism; D009474:Neurons / Q000166:cytology*; D051381:Rats; D012097:Repressor Proteins / Q000378:metabolism; D013997:Time Factors; D000099229:RE1-Silencing Transcription Factor
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D051550:I-kappa B Kinase; D051783:Methyl-CpG-Binding Protein 2; D035683:MicroRNAs; D012097:Repressor Proteins; D000099229:RE1-Silencing Transcription Factor; C509207:MIRN124 microRNA, human