Cytoplasmic dsRNA induces the expression of OCT3/4 and NANOG mRNAs in differentiated human cells

• Published in: The Journal of biological chemistry Vol. 294; no. 50; pp. 18969 - 18979
• Main Authors: Wang, Guanming, Kouwaki, Takahisa, Mugikura, Kazuki, Okamoto, Masaaki, Takaki, Hiromi, Funami, Kenji, Seya, Tsukasa, Oshiumi, Hiroyuki
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 13.12.2019; American Society for Biochemistry and Molecular Biology
• Subjects: Cell Differentiation; Cell Line; Cytoplasm - chemistry; Cytoplasm - metabolism; Humans; Immunology; induced pluripotent stem cell (iPS cell) (iPSC); innate immunity; interferon regulatory factor (IRF); Nanog Homeobox Protein - genetics; Nanog Homeobox Protein - metabolism; Octamer Transcription Factor-3 - genetics; Octamer Transcription Factor-3 - metabolism; Organic Cation Transport Proteins - genetics; Organic Cation Transport Proteins - metabolism; RIG-I-like receptor (RLR); RNA, Double-Stranded - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; signal transduction; virus; induced pluripotent stem cell (iPS cell) (iPSC); innate immunity; signal transduction; virus; RIG-I-like receptor (RLR); interferon regulatory factor (IRF)
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.RA119.009783

Cytoplasmic dsRNA is recognized by RNA helicase RIG-I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5), triggering induction of the innate immune response via the mitochondrial antiviral signaling protein (MAVS). In contrast, extracellular dsRNA is internalized into endosomes and recognized by Toll-like receptor 3 (TLR3), which triggers signaling via the Toll-like receptor adaptor molecule 1 (TICAM-1). Poly(I:C) is a synthetic dsRNA analog and increases the expression of octamer-binding protein 3/4 (OCT3/4), NANOG, and SRY-box (SOX) mRNAs during pluripotency induction. However, the mechanism underlying this increase is unclear. Here, we focused on the mechanism of poly(I:C)-induced expression of stem cell-specific genes in human somatic cells. Addition of poly(I:C) to human fibroblast culture medium did not increase OCT3/4 mRNA expression, but poly(I:C) transfection markedly increased OCT3/4 expression and induced nuclear localization of the OCT3/4 protein, implying that not TLR3, but RIG-I and MDA5 are required for OCT3/4 expression. Moreover, although cytoplasmic dsRNA increased OCT3/4 mRNA, cytoplasmic dsDNAs, such as salmon sperm DNA and poly(dA:dT), did not. Interestingly, the expression of NANOG, SOX2, Krüppel-like factor 4 (KLF4), and proto-oncogene c-Myc was also increased by cytoplasmic dsRNA. Of note, siRNAs that silenced MAVS and interferon regulatory factor 1 (IRF1) expression reduced OCT3/4 levels after stimulation with poly(I:C); however, an NF-κB inhibitor and siRNA-mediated knockdown of proto-oncogene c-Jun did not significantly reduce the mRNA levels. We conclude that cytoplasmic dsRNA increases the expression of stem cell-specific genes in human somatic cells in a MAVS- and IRF1-dependent manner.