Vizantin inhibits endotoxin-mediated immune responses via the TLR 4/MD-2 complex

• Published in: The Journal of immunology (1950) 2014-11, Vol.193 (9), p.4507-4514
• Main Authors: Oda, Masataka, Yamamoto, Hirofumi, Shibutani, Masahiro, Nakano, Mayo, Yabiku, Kenta, Tarui, Takafumi, Kameyama, Naoya, Shirakawa, Daiki, Obayashi, Sumiyo, Watanabe, Naoyuki, Nakase, Hiroshi, Suenaga, Midori, Matsunaga, Yoichi, Nagahama, Masahiro, Takahashi, Hironobu, Imagawa, Hiroshi, Kurosawa, Mie, Terao, Yutaka, Nishizawa, Mugio, Sakurai, Jun
• Format: Article
• Language: English
• Subjects: Animals; Chemokine CCL4 - biosynthesis; Cytokines - biosynthesis; Endotoxins - immunology; Gene Expression; Glycolipids - metabolism; Glycolipids - pharmacology; HEK293 Cells; Humans; Immunity - drug effects; Immunity - genetics; Inflammation Mediators - metabolism; Lipopolysaccharides - immunology; Lipopolysaccharides - pharmacology; Lymphocyte Antigen 96 - chemistry; Lymphocyte Antigen 96 - genetics; Lymphocyte Antigen 96 - metabolism; Macrophages - chemistry; Macrophages - drug effects; Macrophages - immunology; Macrophages - metabolism; Mice; Mice, Knockout; Models, Molecular; Protein Binding; Protein Conformation; Protein Transport; Toll-Like Receptor 4 - genetics; Toll-Like Receptor 4 - metabolism; Trehalose - analogs & derivatives; Trehalose - metabolism; Trehalose - pharmacology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.1401796

Vizantin has immunostimulating properties and anticancer activity. In this study, we investigated the molecular mechanism of immune activation by vizantin. THP-1 cells treated with small interfering RNA for TLR-4 abolished vizantin-induced macrophage activation processes such as chemokine release. In addition, compared with wild-type mice, the release of MIP-1β induced by vizantin in vivo was significantly decreased in TLR-4 knockout mice, but not in TLR-2 knockout mice. Vizantin induced the release of IL-8 when HEK293T cells were transiently cotransfected with TLR-4 and MD-2, but not when they were transfected with TLR-4 or MD-2 alone or with TLR-2 or TLR-2/MD-2. A dipyrromethene boron difluoride-conjugated vizantin colocalized with TLR-4/MD-2, but not with TLR-4 or MD-2 alone. A pull-down assay with vizantin-coated magnetic beads showed that vizantin bound to TLR-4/MD-2 in extracts from HEK293T cells expressing both TLR-4 and MD-2. Furthermore, vizantin blocked the LPS-induced release of TNF-α and IL-1β and inhibited death in mice. We also performed in silico docking simulation analysis of vizantin and MD-2 based on the structure of MD-2 complexed with the LPS antagonist E5564; the results suggested that vizantin could bind to the active pocket of MD-2. Our observations show that vizantin specifically binds to the TLR-4/MD-2 complex and that the vizantin receptor is identical to the LPS receptor. We conclude that vizantin could be an effective adjuvant and a therapeutic agent in the treatment of infectious diseases and the endotoxin shock caused by LPS.