Retinoic acid-inducible gene-I is induced by interferon-γ and regulates CXCL11 expression in HeLa cells

Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH box family proteins, which have diverse roles in the regulation of gene expression and cellular functions. RIG-I is one of the factors regulated by interferon (IFN)-γ and regarded as an intracellular signaling molecule for IFN-γ. IFN-γ is a major cytokine and also suggested to be involved in embryonal implantation and pregnancy. It is demonstrated that IFN-γ stimulates endometrial epithelial cells to produce CXCL11, which is implicated in implantation. The aim of the present study was to investigate the effect of IFN-γ on RIG-I expression in HeLa cells, a cell line derived from human uterine carcinoma. We found that RIG-I mRNA and protein were expressed in HeLa cells stimulated with IFN-γ. The effect of IFN-γ was observed in concentration- and time-dependent manners. The RNA interference against RIG-I resulted in the suppression of the IFN-γ-induced CXCL11 expression. Immunohistochemical studies revealed the RIG-I expression in the normal human endometrium, suggesting a possible role of RIG-I in human reproductive organs.