title: Gene expression profiling in non-human primate jejunum, ileum and colon after total-body irradiation: a comparative study of segment-specific molecular and cellular responses.
abstract: BACKGROUND
  Although extensive studies have investigated radiation-induced injuries in particular gastrointestinal (GI) segments, a systematic comparison among the different segments on the basis of mode, magnitude and mechanism has not been reported. Here, a comparative study of segment-specific molecular and cellular responses was performed on jejunum, ileum and colon obtained at three time points (4, 7 and 12 days after irradiation) from non-human primate (Rhesus macaque) models exposed to 6.7 Gy or 7.4 Gy total body irradiation (TBI).
  
  
  RESULTS
  Pathway analysis on the gene expression profiles identified radiation-induced time-, dose- and segment-dependent activation of tumor necrosis factor α (TNFα) cascade, tight junction, apoptosis, cell cycle control/DNA damage repair and coagulation system signaling. Activation of these signaling pathways suggests that colon sustained the severest mucosal barrier disruption and inflammation, and jejunum the greatest DNA damage, apoptosis and endothelial dysfunction. These more pronounced alterations correlate with the high incidence of macroscopic pathologies that are observed in the colon after TBI. Compared to colon and jejunum, ileum was resistant to radiation injury. In addition to the identification a marked increase of TNFα cascade, this study also identified radiation induced strikingly up-regulated tight junction gene CLDN2 (196-fold after 7.4-Gy TBI), matrix degradation genes such as MMP7 (increased 11- and 41-fold after 6.7-Gy and 7.4-Gy TBI), and anoikis mediated gene EDA2R that mediate mucosal shedding and barrier disruption.
  
  
  CONCLUSIONS
  This is the first systematic comparative study of the molecular and cellular responses to radiation injury in jejunum, ileum and colon. The strongest activation of TNFα cascades and the striking up-regulation of its down-stream matrix-dissociated genes suggest that TNFα modulation could be a target for mitigating radiation-induced mucosal barrier disruption.
authors.affiliation: Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA. jzheng@uams.edu.
authors.forename: Junying
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA. WangJunru@uams.edu.
authors.forename: Junru
authors.initials: J
authors.lastname: Wang
authors.affiliation: CiToxLAB North America, Laval, Quebec, Canada, H7V 4B3. pouliotm@ca.citoxlab.com.
authors.forename: Mylene
authors.initials: M
authors.lastname: Pouliot
authors.affiliation: CiToxLAB North America, Laval, Quebec, Canada, H7V 4B3. AUTHIERS@ca.citoxlab.com.
authors.forename: Simon
authors.initials: S
authors.lastname: Authier
authors.affiliation: Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA. DZhou@uams.edu.
authors.forename: Daohong
authors.initials: D
authors.lastname: Zhou
authors.affiliation: Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, TX, 77030, USA. David.S.Loose@uth.tmc.edu.
authors.forename: David S
authors.initials: DS
authors.lastname: Loose
authors.affiliation: Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205, USA. mhjensen@uams.edu.|Surgical Service, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, 72205, USA. mhjensen@uams.edu.
authors.forename: Martin
authors.initials: M
authors.lastname: Hauer-Jensen
mesh_terms: D000818:Animals; D023102:Anoikis / Q000235:genetics; D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle; D016000:Cluster Analysis; D003106:Colon / Q000276:immunology / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000528:radiation effects*; D007082:Ileum / Q000276:immunology / Q000378:metabolism*; D018928:Immunity, Mucosal / Q000235:genetics / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism / Q000528:radiation effects; D007583:Jejunum / Q000276:immunology / Q000378:metabolism*; D008253:Macaca mulatta; D008297:Male; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects; D019108:Tight Junctions / Q000378:metabolism; D059467:Transcriptome; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014916:Whole-Body Irradiation
chemical_list: D018336:Receptors, Aryl Hydrocarbon; D014409:Tumor Necrosis Factor-alpha