A microRNA profile of human CD8+ regulatory T cells and characterization of the effects of microRNAs on Treg cell-associated genes

• DOI: 10.1186/s12967-014-0218-x
• Publication Date: 2014-08-05T01:35:11Z
• Authors: Fadi Jebbawi; Hussein Fayyad-Kazan; Makram Merimi; Philippe Lewalle; Jean-Christophe V...; Oberdan Leo; Pedro Romero; Arsene Burny; Bassam Badran; Philippe Martiat; Redouane Rouas
• Keywords: 0301 basic medicine; Transcription, Genetic; FOXP3; Cell Separation; CD8-Positive T-Lymphocytes; T-Lymphocytes, Regulatory; 03 medical and health sciences; GARP; Antigens, CD; Transduction, Genetic; Humans; CTLA-4 Antigen; 3' Untranslated Regions; Cell Proliferation; Medicine(all); microRNA; Biochemistry, Genetics and Molecular Biology(all); 3' Untranslated Regions/genetics; Antigens, CD/metabolism; CD8-Positive T-Lymphocytes/metabolism; CTLA-4 Antigen/metabolism; Cell Proliferation; Cell Separation; Forkhead Transcription Factors/genetics; Forkhead Transcription Factors/metabolism; Gene Expression Profiling; Gene Expression Regulation; HeLa Cells; Humans; Lentivirus/metabolism; Membrane Proteins/metabolism; MicroRNAs/genetics; MicroRNAs/metabolism; T-Lymphocytes, Regulatory/metabolism; Transcription, Genetic; Transduction, Genetic; Research; Gene Expression Profiling; Lentivirus; Membrane Proteins; Forkhead Transcription Factors; CD8; Regulatory T cells; Sciences bio-médicales et agricoles; 3. Good health; MicroRNAs; Gene Expression Regulation; CTLA-4; Biologie; HeLa Cells

Recently, regulatory T (Treg) cells have gained interest in the fields of immunopathology, transplantation and oncoimmunology. Here, we investigated the microRNA expression profile of human natural CD8(+)CD25(+) Treg cells and the impact of microRNAs on molecules associated with immune regulation.We purified human natural CD8(+) Treg cells and assessed the expression of FOXP3 and CTLA-4 by flow cytometry. We have also tested the ex vivo suppressive capacity of these cells in mixed leukocyte reactions. Using TaqMan low-density arrays and microRNA qPCR for validation, we could identify a microRNA 'signature' for CD8(+)CD25(+)FOXP3(+)CTLA-4(+) natural Treg cells. We used the 'TargetScan' and 'miRBase' bioinformatics programs to identify potential target sites for these microRNAs in the 3'-UTR of important Treg cell-associated genes.The human CD8(+)CD25(+) natural Treg cell microRNA signature includes 10 differentially expressed microRNAs. We demonstrated an impact of this signature on Treg cell biology by showing specific regulation of FOXP3, CTLA-4 and GARP gene expression by microRNA using site-directed mutagenesis and a dual-luciferase reporter assay. Furthermore, we used microRNA transduction experiments to demonstrate that these microRNAs impacted their target genes in human primary Treg cells ex vivo.We are examining the biological relevance of this 'signature' by studying its impact on other important Treg cell-associated genes. These efforts could result in a better understanding of the regulation of Treg cell function and might reveal new targets for immunotherapy in immune disorders and cancer.