title: Lignin-rich enzyme lignin (LREL), a cellulase-treated lignin-carbohydrate derived from plants, activates myeloid dendritic cells via Toll-like receptor 4 (TLR4).
abstract: Lignin-carbohydrates, one of the major cell wall components, are believed to be the structures that form chemical linkage between lignin and cell wall polysaccharides. Due to the molecular complexity of lignin-containing substances, their isolation and the assignment of their biological activities have so far remained a difficult task. Here, we extracted two lignin-containing carbohydrates, lignin-rich enzyme lignin (LREL) and pure enzyme lignin (PEL), from barley husk and demonstrated that they act as immune stimulators of dendritic cells (DCs), which are particularly important in linking innate and adaptive immunity. Thioacidolysis, acid hydrolysis, and mild alkali hydrolysis of both LREL and PEL revealed that their immunostimulatory activities depended on the lignin structure and/or content, neutral sugar content (especially the characteristic distribution of galactose and mannose), and presence of an ester bond. Furthermore, we showed that the immunostimulatory potency of the lignin-carbohydrate depended on its molecular weight and degree of polymerization. We also demonstrated that the LREL-induced activation of DCs was mediated via TLR4. Thus, LREL-induced increases in the expression levels of several cell surface marker proteins, production of inflammatory cytokines IL-12p40 and TNF-α, and activation and nuclear translocation of transcription factors, as was observed in the WT DCs, were completely abrogated in DCs derived from the TLR4(-/-) mice but not in DCs derived from the TLR2(-/-), TLR7(-/-), and TLR9(-/-) mice. We further demonstrated that LRELs isolated from other plant tissues also activated DCs. These immunostimulatory activities of lignin-carbohydrates, extracted from edible plant tissues, could have potential relevance in anti-infectious immunity and vaccine adjuvants.
authors.affiliation: From the Central Laboratories for Key Technologies, Kirin Co, Ltd., 1-13-5 Fukuura, Kanazawa, Yokohama 236-0004, Japan and Ryohei_Tsuji@kirin.co.jp.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Tsuji
authors.affiliation: From the Central Laboratories for Key Technologies, Kirin Co, Ltd., 1-13-5 Fukuura, Kanazawa, Yokohama 236-0004, Japan and.
authors.forename: Hideki
authors.initials: H
authors.lastname: Koizumi
authors.affiliation: the Division of Biological Material Sciences, Department of Biosphere Resources Science, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Dan
authors.initials: D
authors.lastname: Aoki
authors.affiliation: From the Central Laboratories for Key Technologies, Kirin Co, Ltd., 1-13-5 Fukuura, Kanazawa, Yokohama 236-0004, Japan and.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Watanabe
authors.affiliation: From the Central Laboratories for Key Technologies, Kirin Co, Ltd., 1-13-5 Fukuura, Kanazawa, Yokohama 236-0004, Japan and.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sugihara
authors.affiliation: the Division of Biological Material Sciences, Department of Biosphere Resources Science, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Matsushita
authors.affiliation: the Division of Biological Material Sciences, Department of Biosphere Resources Science, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Fukushima
authors.affiliation: From the Central Laboratories for Key Technologies, Kirin Co, Ltd., 1-13-5 Fukuura, Kanazawa, Yokohama 236-0004, Japan and.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Fujiwara
mesh_terms: D000818:Animals; D002241:Carbohydrates / Q000737:chemistry*; D002480:Cellulase / Q000378:metabolism*; D002850:Chromatography, Gel; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D001467:Hordeum / Q000737:chemistry; D008031:Lignin / Q000737:chemistry / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D022423:Myeloid Cells / Q000166:cytology / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000502:physiology*
chemical_list: D002241:Carbohydrates; D016207:Cytokines; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D008031:Lignin; D002480:Cellulase
keywords: Barley; Dendritic Cell; Innate Immunity; Interleukin; Lignin-Carbohydrate; Toll-like Receptor 4 (TLR4); Tumor Necrosis Factor (TNF)