Genomic polymorphisms in 3β-hydroxysterol Δ24-reductase promoter sequences

Authors

  • Nagla Elwy Salem,

    1. Department of Experimental Phylaxiology, Kumamoto University, Kumamoto, Japan
    2. Department of Medical Virology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
    3. Department of Clinical Pathology, Faculty of Medicine Suez Canal University, Ismailia, Egypt
    Search for more papers by this author
  • Makoto Saito,

    1. Department of Experimental Phylaxiology, Kumamoto University, Kumamoto, Japan
    Search for more papers by this author
  • Yuri Kasama,

    1. Department of Experimental Phylaxiology, Kumamoto University, Kumamoto, Japan
    Search for more papers by this author
  • Makoto Ozawa,

    1. Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
    2. Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
    Search for more papers by this author
  • Toshiko Kawabata,

    1. Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
    2. Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
    Search for more papers by this author
  • Shinji Harada,

    1. Department of Medical Virology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
    Search for more papers by this author
  • Hiroko Suda,

    1. Department of Transplantation and Pediatric Surgery, Postgraduate School of Medical Science, Kumamoto University, Kumamoto, Japan
    Search for more papers by this author
  • Katsuhiro Asonuma,

    1. Department of Transplantation and Pediatric Surgery, Postgraduate School of Medical Science, Kumamoto University, Kumamoto, Japan
    Search for more papers by this author
  • Ahmed El-Gohary,

    1. Department of Clinical Pathology, Faculty of Medicine Suez Canal University, Ismailia, Egypt
    Search for more papers by this author
  • Kyoko Tsukiyama-Kohara

    Corresponding author
    1. Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
    2. Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
    • Department of Experimental Phylaxiology, Kumamoto University, Kumamoto, Japan
    Search for more papers by this author

Correspondence

Kyoko Tsukiyama-Kohara, Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.

Tel: +81 99 285 3589; fax: +81 99 285 3589; email: kkohara@agri.kagoshima-u.ac.jp

ABSTRACT

It was recently reported by the present team that 3β-hydroxysterol Δ24-reductase (DHCR24) is induced by hepatitis C virus (HCV) infection. In addition, upregulation of DHCR24 impairs p53 activity. In human hepatoma HuH-7 cells, the degree of DHCR24 expression is higher than in normal hepatic cell lines (WRL68) at the transcriptional level. The genomic promoter sequence of DHCR24 was characterized and nucleotide substitutions were observed in HuH-7 cells at nucleotide numbers −1453 (G to A), −1420 (G to T), −488 (A to C) and −200 (G to C). The mutations of these sequences from HuH-7 cell types to WRL68 cell types suppressed DHCR24 gene promoter activity. The sequences were further characterized in hepatocytes from patient tissues. Four tissues from HCV-positive patients with cirrhosis or hepatocellular carcinoma (#1, 2, 3, 5) possessed HuH-7 cell type sequences. Interestingly, one patient with liver cirrhosis (#4) possessed WRL68 cell-type sequences; this patient had been infected with HCV and was HCV negative for 17 years after interferon therapy. Next, the effect of HCV infection on these polymorphisms was examined in humanized chimeric mouse liver and HuH-7 cells. The human hepatocytes possess WRL68 cell type and did not show the nucleotide substitution after HCV infection. The HCV-replicon was removed by interferon treatment and established the cured K4 cells. These cells possess HuH-7 cell type sequences. Thus, this study showed the genomic polymorphism in DHCR24 promoter is not directly influenced by HCV infection.

Ancillary