title: MicroRNA-146a and microRNA-146b regulate human dendritic cell apoptosis and cytokine production by targeting TRAF6 and IRAK1 proteins.
abstract: We have previously reported 27 differentially expressed microRNAs (miRNAs) during human monocyte differentiation into immature dendritic cells (imDCs) and mature DCs (mDCs). However, their roles in DC differentiation and function remain largely elusive. Here, we report that microRNA (miR)-146a and miR-146b modulate DC apoptosis and cytokine production. Expression of miR-146a and miR-146b was significantly increased upon monocyte differentiation into imDCs and mDCs. Silencing of miR-146a and/or miR-146b in imDCs and mDCs significantly prevented DC apoptosis, whereas overexpressing miR-146a and/or miR-146b increased DC apoptosis. miR-146a and miR-146b expression in imDCs and mDCs was inversely correlated with TRAF6 and IRAK1 expression. Furthermore, siRNA silencing of TRAF6 and/or IRAK1 in imDCs and mDCs enhanced DC apoptosis. By contrast, lentivirus overexpression of TRAF6 and/or IRAK1 promoted DC survival. Moreover, silencing of miR-146a and miR-146b expression had little effect on DC maturation but enhanced IL-12p70, IL-6, and TNF-α production as well as IFN-γ production by IL-12p70-mediated activation of natural killer cells, whereas miR-146a and miR-146b overexpression in mDCs reduced cytokine production. Silencing of miR-146a and miR-146b in DCs also down-regulated NF-κB inhibitor IκBα and increased Bcl-2 expression. Our results identify a new negative feedback mechanism involving the miR-146a/b-TRAF6/IRAK1-NF-κB axis in promoting DC apoptosis.
authors.affiliation: From the Department of Pediatrics, Division of Hematology, Oncology, and Stem Cell Transplantation, and.
authors.forename: Haein
authors.initials: H
authors.lastname: Park
authors.affiliation: From the Department of Pediatrics, Division of Hematology, Oncology, and Stem Cell Transplantation, and.
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.affiliation: the Institute of Oral Health, School of Dentistry, University of Alabama at Birmingham, Birmingham, Alabama 35233.
authors.forename: Changming
authors.initials: C
authors.lastname: Lu
authors.affiliation: From the Department of Pediatrics, Division of Hematology, Oncology, and Stem Cell Transplantation, and the Departments of Microbiology and Immunology, Cell Biology and Anatomy, Pathology, and Medicine, New York Medical College, Valhalla, New York 10595 and.
authors.forename: Mitchell S
authors.initials: MS
authors.lastname: Cairo
authors.affiliation: From the Department of Pediatrics, Division of Hematology, Oncology, and Stem Cell Transplantation, and the Departments of Microbiology and Immunology, Cell Biology and Anatomy, xianzheng_zhou@nymc.edu.
authors.forename: Xianzheng
authors.initials: X
authors.lastname: Zhou
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D003713:Dendritic Cells / Q000166:cytology* / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D053592:Interleukin-1 Receptor-Associated Kinases / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology; D060888:Real-Time Polymerase Chain Reaction; D048029:TNF Receptor-Associated Factor 6 / Q000235:genetics / Q000378:metabolism*
chemical_list: D016207:Cytokines; C542542:MIRN146 microRNA, human; D035683:MicroRNAs; D048029:TNF Receptor-Associated Factor 6; C507768:IRAK1 protein, human; D053592:Interleukin-1 Receptor-Associated Kinases
keywords: Apoptosis; Cytokine; Dendritic Cell; Differentiation; IL-1 Receptor-associated Kinases (IRAK); MicroRNA (miRNA); NF-kappa B (NF-κB); TNF Receptor-associated Factor (TRAF); miR-146