title: HIV-TAT mediated protein transduction of Cu/Zn-superoxide dismutase-1 (SOD1) protects skin cells from ionizing radiation.
abstract: BACKGROUND
  Radiation-induced skin injury remains a serious concern during radiotherapy. Cu/Zn-superoxide dismutase (Cu/Zn-SOD, SOD1) is a conserved enzyme for scavenging superoxide radical in cells. Because of the integrity of cell membranes, exogenous molecule is not able to be incorporated into cells, which limited the application of natural SOD1. The aim of this study was to evaluate the protective role of HIV-TAT protein transduction domain mediated protein transduction of SOD1 (TAT-SOD1) against ionizing radiation.
  
  
  METHODS
  The recombinant TAT-SOD1 and SOD1 were obtained by prokaryotic-based protein expression system. The transduction effect and biological activity of TAT-SOD1 was measured by immunofluorescence and antioxidant capability assays in human keratinocyte HaCaT cells. Mito-Tracker staining, reactive oxygen species (ROS) generation assay, cell apoptosis analysis and malondialdehyde (MDA) assay were used to access the protective effect of TAT- SOD1.
  
  
  RESULTS
  Uptake of TAT-SOD1 by HaCaT cells retained its biological activity. Compared with natural SOD1, the application of TAT-SOD1 significantly enhanced the viability and decreased the apoptosis induced by X-ray irradiation. Moreover, TAT-SOD1 reduced ROS and preserved mitochondrial integrity after radiation exposure in HaCaT cells. Radiation-induced γH2AX foci, which are representative of DNA double strand breaks, were decreased by pretreatment with TAT-SOD1. Furthermore, subcutaneous application of TAT-SOD1 resulted in a significant decrease in 45 Gy electron beam-induced ROS and MDA concentration in the skins of rats.
  
  
  CONCLUSIONS
  This study provides evidences for the protective role of TAT-SOD1 in alleviating radiation-induced damage in HaCaT cells and rat skins, which suggests a new therapeutic strategy for radiation-induced skin injury.
authors.forename: Qing
authors.initials: Q
authors.lastname: Gu
authors.forename: Tienan
authors.initials: T
authors.lastname: Feng
authors.forename: Han
authors.initials: H
authors.lastname: Cao
authors.forename: Yiting
authors.initials: Y
authors.lastname: Tang
authors.forename: Xin
authors.initials: X
authors.lastname: Ge
authors.forename: Judong
authors.initials: J
authors.lastname: Luo
authors.forename: Jiao
authors.initials: J
authors.lastname: Xue
authors.forename: Jinyong
authors.initials: J
authors.lastname: Wu
authors.forename: Hongying
authors.initials: H
authors.lastname: Yang
authors.affiliation: School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou 215123, China. zhang.shuyu@hotmail.com.
authors.forename: Shuyu
authors.initials: S
authors.lastname: Zhang
authors.forename: Jianping
authors.initials: J
authors.lastname: Cao
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry; D017209:Apoptosis; D002460:Cell Line; D002462:Cell Membrane / Q000528:radiation effects; D002470:Cell Survival; D053903:DNA Breaks, Double-Stranded; D016166:Free Radical Scavengers; D006657:Histones / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000528:radiation effects*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D021381:Protein Transport; D011839:Radiation, Ionizing; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins / Q000737:chemistry; D012867:Skin / Q000166:cytology / Q000528:radiation effects*; D013482:Superoxide Dismutase / Q000378:metabolism*; D000072105:Superoxide Dismutase-1; D013481:Superoxides / Q000737:chemistry; D014965:X-Rays; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; C468783:H2AX protein, human; D006657:Histones; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; C000606290:SOD1 protein, human; C577575:gamma-H2AX protein, rat; D054322:tat Gene Products, Human Immunodeficiency Virus; D013481:Superoxides; D008315:Malondialdehyde; C000606292:Sod1 protein, rat; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1