title: High dose ionizing radiation regulates micro RNA and gene expression changes in human peripheral blood mononuclear cells.
abstract: BACKGROUND
  High dose ionizing radiation (IR) induces potent toxic cell effects mediated by either direct DNA damage or the production of reactive oxygen species (ROS). IR-induced modulations in multiple biological processes have been proposed to be partly regulated by radiosensitive microRNA (miRNA). In order to gain new insights into the role of miRNAs in the regulation of biological processes after IR, we have investigated changes in mRNA and miRNA expression after high dose IR.
  
  
  RESULTS
  IR induced changes in the mRNA and miRNA profiles of human peripheral blood mononuclear cells (PBMCs). When comparing non-irradiated and irradiated samples, we detected a time-dependent increase in differentially expressed mRNAs and miRNAs, with the highest differences detectable 20 hours after exposure. Gene ontology analysis revealed that very early events (up to 4 hours) after irradiation were specifically associated with p53 signaling and apoptotic pathways, whereas a large number of diverse cellular processes were deregulated after 20 hours. Transcription factor analysis of all up-regulated genes confirmed the importance of p53 in the early post-irradiation phase. When analyzing miRNA expression, we found 177 miRNAs that were significantly regulated in the late post-irradiation phase. Integrating miRNA and target gene expression data, we found a significant negative correlation between miRNA-mRNA and identified hepatic leukemia factor (HLF) as a transcription factor down-regulated in the response to IR. These regulated miRNAs and the HLF target genes were involved in modulating radio-responsive pathways, such as apoptosis, the MAKP signaling pathway, endocytosis, and cytokine-cytokine interactions.
  
  
  CONCLUSIONS
  Using a large dataset of mRNA and miRNA expression profiles, we describe the interplay of mRNAs and miRNAs in the regulation of gene expression in response to IR at a posttranscriptional level and their involvement in the modulation of radiation-induced biological pathways.
authors.forename: Lucian
authors.initials: L
authors.lastname: Beer
authors.forename: Rudolf
authors.initials: R
authors.lastname: Seemann
authors.forename: Robin
authors.initials: R
authors.lastname: Ristl
authors.forename: Adolf
authors.initials: A
authors.lastname: Ellinger
authors.forename: Mohammad Mahdi
authors.initials: MM
authors.lastname: Kasiri
authors.forename: Andreas
authors.initials: A
authors.lastname: Mitterbauer
authors.forename: Matthias
authors.initials: M
authors.lastname: Zimmermann
authors.forename: Christian
authors.initials: C
authors.lastname: Gabriel
authors.forename: Mariann
authors.initials: M
authors.lastname: Gyöngyösi
authors.forename: Walter
authors.initials: W
authors.lastname: Klepetko
authors.affiliation: Department of Thoracic Surgery, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria. michael.mildner@meduniwien.ac.at.
authors.forename: Michael
authors.initials: M
authors.lastname: Mildner
authors.forename: Hendrik Jan
authors.initials: HJ
authors.lastname: Ankersmit
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D050976:Basic-Leucine Zipper Transcription Factors / Q000097:blood / Q000235:genetics; D004307:Dose-Response Relationship, Radiation; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000528:radiation effects*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism / Q000528:radiation effects*; D008297:Male; D035683:MicroRNAs / Q000097:blood / Q000235:genetics*; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D011839:Radiation, Ionizing; D015398:Signal Transduction / Q000528:radiation effects*; D016159:Tumor Suppressor Protein p53 / Q000097:blood / Q000235:genetics* / Q000378:metabolism*; D055815:Young Adult
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; C490671:HLF protein, human; D035683:MicroRNAs; D012333:RNA, Messenger; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53