title: Comparison of acute proton, photon, and low-dose priming effects on genes associated with extracellular matrix and adhesion molecules in the lungs.
abstract: BACKGROUND
  Crew members on space missions inevitably are exposed to low background radiation and can receive much higher doses during solar particle events (SPE) that consist primarily of protons. Ionizing radiation could cause lung pathologies. Cell adhesion molecules (CAM) are believed to participate in fibrogenesis. Interactions between CAM and extracellular matrix (ECM) affect epithelial repair mechanisms in the lung. However, there are very limited data on biological effects of protons on normal lung tissue. Numerous reports have shown that exposure to low-dose/low-dose-rate (LDR) radiation can result in radioadaptation that renders cells more resistant to subsequent acute radiation. The goal of this study was to compare expression of genes associated with ECM and CAM, as well as critical profibrotic mediators, in mouse lungs after acute irradiation with photons and protons, and also determine whether pre-exposure to LDR γ-rays induces an adaptive effect.
  
  
  RESULTS
  Overall, a marked difference was present in the proton vs. photon groups in gene expression. When compared to 0 Gy, more genes were affected by protons than by photons at both time points (11 vs. 6 on day 21 and 14 vs. 8 on day 56), and all genes affected by protons were upregulated. Many genes were modulated by LDR γ-rays when combined with photons or protons. Col1a1, mmp14, and mmp15 were significantly upregulated by all radiation regimens on day 21. Similarly, the change in expression of profibrotic proteins was also detected after acute and combination irradiation.
  
  
  CONCLUSIONS
  These data show that marked differences were present between acutely delivered protons and photons in modulating genes, and the effect of protons was more profound than that of photons. Pre-exposure to LDR γ-rays 'normalized' some genes that were modified by acute irradiation.
authors: Department of Radiation Medicine, Radiation Research Laboratories and Department of Basic Sciences, Loma Linda University, Loma Linda, California, USA.|Department of Pathological Anatomy, Nantong University, Nantong, China.
authors: Jian
authors: J
authors: Tian
authors: Department of Otolaryngology, Loma Linda University Medical Center, Loma Linda, California, 92354, USA.
authors: Sisi
authors: S
authors: Tian
authors: Department of Radiation Medicine, Radiation Research Laboratories and Department of Basic Sciences, Loma Linda University, Loma Linda, California, USA.
authors: Daila S
authors: DS
authors: Gridley
references: Curr Pharm Des. 2003;9(1):39-49
references: 12570673
references: Int J Radiat Oncol Biol Phys. 2006 Dec 1;66(5):1281-93
references: 17126203
references: Clin Immunol. 2001 Jun;99(3):308-19
references: 11358425
references: J Pathol. 2008 Jan;214(2):199-210
references: 18161745
references: Biol Sci Space. 2004 Dec;18(4):201-5
references: 15858386
references: In Vivo. 2001 Jan-Feb;15(1):87-92
references: 11286136
references: Cancer Cell. 2011 Nov 15;20(5):576-90
references: 22094253
references: Clin Chest Med. 2005 Sep;26(3):415-38, vi
references: 16140136
references: Am J Med. 1999 Sep;107(3):268-79
references: 10492321
references: Oncogene. 2005 Nov 14;24(50):7443-54
references: 16288291
references: Radiat Res. 2006 Dec;166(6):839-48
references: 17149983
references: J Appl Physiol (1985). 2010 Jan;108(1):162-71
references: 19850731
references: Semin Oncol. 2005 Apr;32(2 Suppl 3):S42-54
references: 16015535
references: Braz J Med Biol Res. 2005 Oct;38(10):1521-30
references: 16172745
references: Semin Cell Dev Biol. 2008 Feb;19(1):24-33
references: 17702616
references: Adv Space Res. 2002;30(4):1033-44
references: 12539784
references: Mol Cell. 2001 Jun;7(6):1267-78
references: 11430829
references: Oncology (Williston Park). 2010 Oct;24(11):1052-7
references: 21155458
references: Eur J Biochem. 1997 Dec 15;250(3):751-7
references: 9461298
references: Thorax. 2009 Dec;64(12):1053-61
references: 19850962
references: Mol Endocrinol. 1996 Sep;10(9):1077-83
references: 8885242
references: Radiat Res. 2009 Jul;172(1):30-41
references: 19580505
references: Gen Thorac Cardiovasc Surg. 2012 Mar;60(3):127-31
references: 22419179
references: J Biol Chem. 1983 Jun 10;258(11):7155-60
references: 6602130
references: Am J Respir Cell Mol Biol. 2006 Aug;35(2):252-9
references: 16574941
references: Am J Physiol Lung Cell Mol Physiol. 2010 Jun;298(6):L715-31
references: 20363851
references: Cancer Res. 2002 Mar 15;62(6):1613-8
references: 11912130
references: J Clin Oncol. 2007 Sep 1;25(25):3991-4008
references: 17577017
references: JAMA. 1997 Jun 25;277(24):1957-61
references: 9200637
references: Radiother Oncol. 2010 Oct;97(1):149-61
references: 20888056
references: Technol Cancer Res Treat. 2003 Oct;2(5):413-26
references: 14529306
references: J Mammary Gland Biol Neoplasia. 2010 Jun;15(2):117-34
references: 20490631