Superoxide Dismutase Gene Expression Induced by Lipopolysaccharide in Alveolar Macrophage of Rat

폐포대식세포에서 내독소 자극에 의한 Superoxide Dismutase 유전자발현의 조절 기전

  • Park, Kye-Young (Department of Internal Medicine and Tuberculosis Research Institute, Seoul National University College of Medicine) ;
  • Yoo, Chul-Gyu (Department of Internal Medicine and Tuberculosis Research Institute, Seoul National University College of Medicine) ;
  • Kim, Young-Whan (Department of Internal Medicine and Tuberculosis Research Institute, Seoul National University College of Medicine) ;
  • Han, Sung-Koo (Department of Internal Medicine and Tuberculosis Research Institute, Seoul National University College of Medicine) ;
  • Shim, Young-Soo (Department of Internal Medicine and Tuberculosis Research Institute, Seoul National University College of Medicine) ;
  • Hyun, In-Gyu (Department of Internal Medicine, Hallym University College of Medicine)
  • 박계영 (서울대학교 의과대학 내과학교실 및 결핵연구소) ;
  • 유철규 (서울대학교 의과대학 내과학교실 및 결핵연구소) ;
  • 김영환 (서울대학교 의과대학 내과학교실 및 결핵연구소) ;
  • 한성구 (서울대학교 의과대학 내과학교실 및 결핵연구소) ;
  • 심영수 (서울대학교 의과대학 내과학교실 및 결핵연구소) ;
  • 현인규 (한림대학교 의과대학 내과학교실)
  • Published : 1995.08.31

Abstract

Background: In the pathogenesis of acute lung injury induced by lipopolysaccharide(LPS), oxygen radiclls are known to be involved in one part. Superoxide dismutase(SOD) protects oxygen radical-induced tissue damage by dismutating superoxide to hydrogen peroxide. In eukaryotic cells, two forms of SOD exist intracellularly as a cytosolic, dimeric copper/zinc-containing SOD(CuZnSOD) and a mitochondrial, tetrameric manganese-containing SOD(MnSOD). But there has been little information about SOD gene expression and its regulation in pulmonary alveolar macrophages(PAMs). The objective of this study is to evaluate the SOD gene expression induced by LPS and its regulation in PAMs of rat. Method: In Sprague-Dawley rats, PAMs obtained by broncholaveolar lavage were purified by adherence to plastic plate. To study the effect of LPS on the SOD gene expression of PAMs, they were stimulated with different doses of LPS($0.01{\mu}g/ml{\sim}10{\mu}g/ml$) and for different intervals(0, 2, 4, 8, 24hrs). Also for evaluating the level of SOD gene regulation actinomycin D(AD) or cycloheximide(CHX) were added respectively. To assess whether LPS altered SOD mRNA stability, the rate of mRNA decay was determined in control group and LPS-treated group. Total cellular RNA extraction by guanidinium thiocyanate/phenolfchlorofonn method and Northern blot analysis by using a $^{32}P$-labelled rat MnSOD and CuZnSOD cDNAs were performed. Results: The expression of mRNA in MnSOD increased dose-dependently, but not in CuZnSOD. MnSOD mRNA expression peaked at 8 hours after LPS treatment. Upregulation of MnSOD mRNA expression induced by LPS was suppressed by adding AD or CHX respectively. MnSOD mRNA stability was not altered by LPS. Conclusion: These findings show that PAMs of rat could be an important source of SOD in response to LPS, and suggest that their MnSOD mRNA expression may be regulated transcriptionally and require de novo protein synthesis without affecting mRNA stability.