title: PU.1-dependent transcriptional regulation of miR-142 contributes to its hematopoietic cell-specific expression and modulation of IL-6.
abstract: MicroRNAs (miRs) have emerged as critical modulators of immune responses, but little is known about their transcriptional regulation and tissue specificity. miR-142 is specifically expressed in hematopoietic tissues and plays an important role in regulating immunity. In this study we identified the key transcriptional elements for regulation of miR-142 and its impact on TLR4-mediated expression of IL-6. The PU.1, C/EBPβ, and Runx1 transcription factor binding sites are conserved and constitutively occupied by the respective transcription factors in the miR-142 gene promoter only in the hematopoietic cells. Specific knockdown experiments in hematopoietic cells and rescue experiments in nonhematopoietic cells show that PU.1 is critical for miR-142 gene expression and that it synergizes with Runx1, C/EBPβ, and CBFβ. Furthermore, TLR4 stimulation enhanced miR-155 whereas experiments with knockdown and mimic expression of miR-155 demonstrated that miR-155 negatively regulates miR-142-3p expression by targeting PU.1. Thus, TLR4 stimulation represses PU.1, resulting in downregulation of miR-142 and increased expression of IL-6. These results collectively reveal the direct cis-acting sequences of miR-142 specific promoter and that transcription factor PU.1 is necessary for its exclusive expression in hematopoietic cells and regulation of IL-6.
authors.affiliation: Department of Internal Medicine, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109, USA.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Sun
authors.forename: John
authors.initials: J
authors.lastname: Sun
authors.forename: Toubai
authors.initials: T
authors.lastname: Tomomi
authors.forename: Evelyn
authors.initials: E
authors.lastname: Nieves
authors.forename: Nathan
authors.initials: N
authors.lastname: Mathewson
authors.forename: Hiroya
authors.initials: H
authors.lastname: Tamaki
authors.forename: Rebecca
authors.initials: R
authors.lastname: Evers
authors.forename: Pavan
authors.initials: P
authors.lastname: Reddy
mesh_terms: D000818:Animals; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D015536:Down-Regulation / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000276:immunology* / Q000378:metabolism*; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D041681:NIH 3T3 Cells; D061251:Primary Cell Culture; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000502:physiology; D015534:Trans-Activators / Q000502:physiology*; D014158:Transcription, Genetic / Q000276:immunology*; D015854:Up-Regulation / Q000276:immunology; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D015850:Interleukin-6; D035683:MicroRNAs; D011518:Proto-Oncogene Proteins; D051197:Toll-Like Receptor 4; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1; C529102:Mirn142 microRNA, mouse; C493487:Tlr4 protein, mouse