title: MicroRNAs hsa-miR-99b, hsa-miR-330, hsa-miR-126 and hsa-miR-30c: Potential Diagnostic Biomarkers in Natural Killer (NK) Cells of Patients with Chronic Fatigue Syndrome (CFS)/ Myalgic Encephalomyelitis (ME).
abstract: BACKGROUND
  Chronic Fatigue Syndrome (CFS/ME) is a complex multisystem disease of unknown aetiology which causes debilitating symptoms in up to 1% of the global population. Although a large cohort of genes have been shown to exhibit altered expression in CFS/ME patients, it is currently unknown whether microRNA (miRNA) molecules which regulate gene translation contribute to disease pathogenesis. We hypothesized that changes in microRNA expression in patient leukocytes contribute to CFS/ME pathology, and may therefore represent useful diagnostic biomarkers that can be detected in the peripheral blood of CFS/ME patients.
  
  
  METHODS
  miRNA expression in peripheral blood mononuclear cells (PBMC) from CFS/ME patients and healthy controls was analysed using the Ambion Bioarray V1. miRNA demonstrating differential expression were validated by qRT-PCR and then replicated in fractionated blood leukocyte subsets from an independent patient cohort. The CFS/ME associated miRNA identified by these experiments were then transfected into primary NK cells and gene expression analyses conducted to identify their gene targets.
  
  
  RESULTS
  Microarray analysis identified differential expression of 34 miRNA, all of which were up-regulated. Four of the 34 miRNA had confirmed expression changes by qRT-PCR. Fractionating PBMC samples by cell type from an independent patient cohort identified changes in miRNA expression in NK-cells, B-cells and monocytes with the most significant abnormalities occurring in NK cells. Transfecting primary NK cells with hsa-miR-99b or hsa-miR-330-3p, resulted in gene expression changes consistent with NK cell activation but diminished cytotoxicity, suggesting that defective NK cell function contributes to CFS/ME pathology.
  
  
  CONCLUSIONS
  This study demonstrates altered microRNA expression in the peripheral blood mononuclear cells of CFS/ME patients, which are potential diagnostic biomarkers. The greatest degree of miRNA deregulation was identified in NK cells with targets consistent with cellular activation and altered effector function.
authors.affiliation: CFS Group, St George´s University of London, Cranmer Terrace, London, United Kingdom.|Centre for Haemato-Oncology, Bart's cancer institute, Queen Mary University of London, London, United Kingdom.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Petty
authors.affiliation: Centre for Immunobiology, The Blizzard institute, Queen Mary University of London, London, United Kingdom.
authors.forename: Neil E
authors.initials: NE
authors.lastname: McCarthy
authors.affiliation: Centre for Haemato-Oncology, Bart's cancer institute, Queen Mary University of London, London, United Kingdom.
authors.forename: Rifca
authors.initials: R
authors.lastname: Le Dieu
authors.affiliation: CFS Group, St George´s University of London, Cranmer Terrace, London, United Kingdom.|Grupo de Salud Publica, Escuela de Medicine y Ciencias de la Salud, Universidad del Rosario, Quinta de Mutis, Bogotá 111221, Colombia.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Kerr
mesh_terms: D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology; D020869:Gene Expression Profiling; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D007694:Killer Cells, Natural / Q000378:metabolism / Q000473:pathology; D008213:Lymphocyte Activation; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D015854:Up-Regulation
chemical_list: D005819:Genetic Markers; C527111:MIRN126 microRNA, human; C546086:MIRN30b microRNA, human; C570805:MIRN330 microRNA, human; C561679:MIRN99 microRNA, human; D035683:MicroRNAs