title: The TLR3/TICAM-1 pathway is mandatory for innate immune responses to poliovirus infection.
abstract: Cytoplasmic and endosomal RNA sensors recognize RNA virus infection and signals to protect host cells by inducing type I IFN. The cytoplasmic RNA sensors, retinoic acid inducible gene I/melanoma differentiation-associated gene 5, actually play pivotal roles in sensing virus replication. IFN-β promoter stimulator-1 (IPS-1) is their common adaptor for IFN-inducing signaling. Toll/IL-1R homology domain-containing adaptor molecule 1 (TICAM-1), also known as TRIF, is the adaptor for TLR3 that recognizes viral dsRNA in the early endosome in dendritic cells and macrophages. Poliovirus (PV) belongs to the Picornaviridae, and melanoma differentiation-associated gene 5 reportedly detects replication of picornaviruses, leading to the induction of type I IFN. In this study, we present evidence that the TLR3/TICAM-1 pathway governs IFN induction and host protection against PV infection. Using human PVR transgenic (PVRtg) mice, as well as IPS-1(-/-) and TICAM-1(-/-) mice, we found that TICAM-1 is essential for antiviral responses that suppress PV infection. TICAM-1(-/-) mice in the PVRtg background became markedly susceptible to PV, and their survival rates were decreased compared with wild-type or IPS-1(-/-) mice. Similarly, serum and organ IFN levels were markedly reduced in TICAM-1(-/-)/PVRtg mice, particularly in the spleen and spinal cord. The sources of type I IFN were CD8α(+)/CD11c(+) splenic dendritic cells and macrophages, where the TICAM-1 pathway was more crucial for PV-derived IFN induction than was the IPS-1 pathway in ex vivo and in vitro analyses. These data indicate that the TLR3/TICAM-1 pathway functions are dominant in host protection and innate immune responses against PV infection.
authors: Department of Microbiology and Immunology, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan.
authors: Hiroyuki
authors: H
authors: Oshiumi
authors: Masaaki
authors: M
authors: Okamoto
authors: Ken
authors: K
authors: Fujii
authors: Takashi
authors: T
authors: Kawanishi
authors: Misako
authors: M
authors: Matsumoto
authors: Satoshi
authors: S
authors: Koike
authors: Tsukasa
authors: T
authors: Seya
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency / Q000235:genetics; D033942:Adaptor Proteins, Vesicular Transport / Q000172:deficiency / Q000502:physiology* / Q000627:therapeutic use; D000818:Animals; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics; D007370:Interferon Type I / Q000096:biosynthesis / Q000627:therapeutic use; D008264:Macrophages / Q000276:immunology / Q000473:pathology / Q000821:virology; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D041681:NIH 3T3 Cells; D011051:Poliomyelitis / Q000235:genetics / Q000276:immunology* / Q000401:mortality; D017955:Poliovirus / Q000276:immunology; D011991:Receptors, Virus / Q000235:genetics; D051196:Toll-Like Receptor 3 / Q000172:deficiency / Q000502:physiology* / Q000627:therapeutic use; D014709:Vero Cells
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D007370:Interferon Type I; C505371:MAVS protein, human; D011991:Receptors, Virus; C470409:TICAM1 protein, human; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; C066100:poliovirus receptor