title: miR-21 is a negative modulator of T-cell activation.
abstract: microRNAs (miRNAs) are a class of small non-coding RNAs acting as post-transcriptional regulators of gene expression and play fundamental roles in regulating immune response and autoimmunity. We show that memory T-lymphocytes express higher levels of miR-21 compared to naïve T-lymphocytes and that miR-21 expression is induced upon TCR engagement of naïve T-cells. We identify bona fide miR-21 targets by direct immuno-purification and profiling of AGO2-associated mRNAs in Jurkat cells over-expressing miR-21. Our analysis shows that, in T-lymphocytes, miR-21 targets genes are involved in signal transduction. Coherently, TCR signalling is dampened upon miR-21 over-expression in Jurkat cells, resulting in lower ERK phosphorylation, AP-1 activation and CD69 expression. Primary human lymphocytes in which we impaired miR-21 activity, display IFN-γ production enhancement and stronger activation in response to TCR engagement as assessed by CD69, OX40, CD25 and CD127 analysis. By intracellular staining of the endogenous protein in primary T-lymphocytes we validate three key regulators of lymphocyte activation as novel miR-21 targets. Our results highlight an unexpected function of miR-21 as a negative modulator of signal transduction downstream of TCR in T-lymphocytes.
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Carissimi
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Carucci
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Colombo
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, "Sapienza" Università di Roma, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Piconese
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Azzalin
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Cipolletta
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy.
authors.forename: Franca
authors.initials: F
authors.lastname: Citarella
authors.affiliation: Dipartimento di Medicina Interna e Specialità Mediche, "Sapienza" Università di Roma, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barnaba
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Macino
authors.affiliation: Dipartimento di Biotecnologie Cellulari ed Ematologia, "Sapienza" Università di Roma, Italy. Electronic address: valerio.fulci@uniroma1.it.
authors.forename: Valerio
authors.initials: V
authors.lastname: Fulci
mesh_terms: D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D005786:Gene Expression Regulation; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D019169:Jurkat Cells; D016086:Lentivirus / Q000235:genetics; D008213:Lymphocyte Activation / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000235:genetics; D015203:Reproducibility of Results; D015398:Signal Transduction / Q000235:genetics; D013601:T-Lymphocytes / Q000502:physiology*
chemical_list: C527276:CXCR4 protein, human; C554061:GNAQ protein, human; D044385:GTP-Binding Protein alpha Subunits; D047908:Intracellular Signaling Peptides and Proteins; C524940:MIRN21 microRNA, human; D008565:Membrane Proteins; D035683:MicroRNAs; C435927:PLEKHA1 protein, human; D011948:Receptors, Antigen, T-Cell; D019718:Receptors, CXCR4; D007371:Interferon-gamma; D043802:GTP-Binding Protein alpha Subunits, Gq-G11
keywords: AGO2 immunoprecipitation; Acquired immunity; T-lymphocytes; miR-21; miRNA target