Tohoku J. Exp. Med., 2004, 203(4)

Upregulation of Retinoic Acid-Inducible Gene-I in T24 Urinary Bladder Carcinoma Cells Stimulated with Interferon-γ

TADAATSU IMAIZUMI, NORITO YAGIHASHI,¹ MASAHARU HATAKEYAMA, KOJI YAMASHITA, AKIRA ISHIKAWA, KAGEAKI TAIMA,² HIDEMI YOSHIDA, SOROKU YAGIHASHI¹ and KEI SATOH

Department of Vascular Biology, Institute of Brain Science, ¹Department of Pathology, and ²Department of Internal Medicine, Hirosaki University School of Medicine, Hirosaki 036-8562

Urinary bladder epithelial cells play an important role in the host defense against urinary tract infections. Interferon-γ (IFN-γ) is a potent cytokine that regulates immune responses by inducing multiple genes in many types of cells including urinary bladder epithelial cells. Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH-box family, which is involved in various reactions related to RNA metabolism, and is induced in leukemic cells by retinoic acid or in endothelial cells by lipopolysaccharide. We have studied the expression of RIG-I in T24 cells, a cell line derived from human urinary bladder epithelial carcinoma cells. IFN-γ stimulated T24 cells to express RIG-I mRNA and protein in concentration- and time-dependent manners. Immunohistochemical analysis revealed the expression of RIG-I in the urinary bladder epithelium from a patient with chronic urinary tract infection and in a bladder epithelial carcinoma. We conclude that RIG-I may play some role in inflammatory reactions in the urinary tract epithelium.

keywords —— RIG-I; IFN-γ; T24 cells; urinary bladder epithelial cells

© 2004 Tohoku University Medical Press

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Address for reprints: Dr. Tadaatsu Imaizumi, Department of Vascular Biology, Institute of Brain Science, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan.

e-mail: timaizum@cc.hirosaki-u.ac.jp