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Kawahara K. Synthetic chemistry with friendships that unveiled the long-lasting mystery of lipid A. Innate Immun 2019; 25:203-212. [PMID: 30894093 PMCID: PMC6830933 DOI: 10.1177/1753425919835298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 01/22/2019] [Accepted: 01/29/2019] [Indexed: 11/16/2022] Open
Abstract
Endotoxin research in recent years at the molecular level has required chemically synthesized lipid A without contamination by other bioactive components. Total synthesis of Escherichia coli-type lipid A was achieved in the 1980s by the challenging spirits of the scientists at Osaka University, Japan. They clarified the role of lipid A in the immunological activities of endotoxin in collaboration with Japanese and German researchers, based on the friendships that existed between them. This article introduces the great contributions made by three generations of professors, Tetsuo Shiba, Shoichi Kusumoto, and Koichi Fukase, at the Laboratory of Natural Product Chemistry at Osaka University, to the study over four decades of endotoxin.
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Gao J, Guo Z. Progress in the synthesis and biological evaluation of lipid A and its derivatives. Med Res Rev 2018; 38:556-601. [PMID: 28621828 PMCID: PMC5732894 DOI: 10.1002/med.21447] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 03/09/2017] [Accepted: 04/20/2017] [Indexed: 12/31/2022]
Abstract
Lipid A is one of the core structures of bacterial lipopolysaccharides (LPSs), and it is mainly responsible for the strong immunostimulatory activities of LPS through interactions with the Toll-like receptors and other molecules in the human immune system. To obtain structurally homogeneous and well-defined lipid As and its derivatives in quantities meaningful for various biological studies and applications, their chemical synthesis has become a focal point. This review has provided a survey of significant progresses made in the synthesis of lipid A, and its derivatives that carry diverse saturated and unsaturated lipids, have the phosphate group at its reducing end replaced with a more stable phosphate or carboxyl group, or lack the reducing end phosphate or both phosphate groups, as well as progresses in the synthesis of LPS analogs and other lipid A conjugates. These synthetic molecules have facilitated the elucidation of the structure-activity relationships of lipid A useful for the design and development of lipid A based therapeutics, such as those utilized to treat sepsis, and other medical applications, for example the use of monophosphoryl lipid A as a carrier molecule for the study of fully synthetic self-adjuvanting conjugate vaccines. These topics are also briefly covered in the current review.
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Affiliation(s)
- Jian Gao
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan 250100, China
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, 214 Leigh Hall, Gainesville, Florida 32611, United States
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Liu X, Dong T, Zhou Y, Huang N, Lei X. Exploring the Binding Proteins of Glycolipids with Bifunctional Chemical Probes. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Xiaohui Liu
- School of Pharmaceutical Science and Technology; Tianjin University; Tianjin 300072 China
| | - Ting Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences; Peking University; Beijing 100871 China
| | - Yu Zhou
- National Institute of Biological Sciences (NIBS); Changping District Beijing 102206 China
| | - Niu Huang
- National Institute of Biological Sciences (NIBS); Changping District Beijing 102206 China
| | - Xiaoguang Lei
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences; Peking University; Beijing 100871 China
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Liu X, Dong T, Zhou Y, Huang N, Lei X. Exploring the Binding Proteins of Glycolipids with Bifunctional Chemical Probes. Angew Chem Int Ed Engl 2016; 55:14330-14334. [DOI: 10.1002/anie.201608827] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Indexed: 01/06/2023]
Affiliation(s)
- Xiaohui Liu
- School of Pharmaceutical Science and Technology; Tianjin University; Tianjin 300072 China
| | - Ting Dong
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences; Peking University; Beijing 100871 China
| | - Yu Zhou
- National Institute of Biological Sciences (NIBS); Changping District Beijing 102206 China
| | - Niu Huang
- National Institute of Biological Sciences (NIBS); Changping District Beijing 102206 China
| | - Xiaoguang Lei
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Synthetic and Functional Biomolecules Center, and Peking-Tsinghua Center for Life Sciences; Peking University; Beijing 100871 China
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Saitoh SI, Akashi S, Yamada T, Tanimura N, Matsumoto F, Fukase K, Kusumoto S, Kosugi A, Miyake K. Ligand-dependent Toll-like receptor 4 (TLR4)-oligomerization is directly linked with TLR4-signaling. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519040100041001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Toll-like receptor 4 (TLR4) and MD-2 recognize lipid A, the active moiety of microbial lipopolysaccharide (LPS). Little is known about mechanisms for LPS recognition by TLR4/MD-2. We here showed, by using in vitro transfectants, ligand-induced TLR4-oligomerization, which required both membrane CD14 and MD-2. We previously reported that lipid IVa, a lipid A precursor, is agonistic on mouse TLR4/MD-2 but antagonistic on human TLR4/MD-2 and chimeric mouse TLR4/human MD-2. Lipid IVa triggered oligomerization of mouse TLR4/MD-2 but not human TLR4/MD-2 or chimeric mouse TLR4/human MD-2. Further, lipid IVa inhibited lipid A-dependent oligomerization of chimeric mouse TLR4/human MD-2. These results demonstrate that ligand-induced TLR4-oligomerization is directly linked with TLR4-signaling and suggest that MD-2 has an important role in regulating TLR4-oligomerization.
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Affiliation(s)
- Shin-ichiroh Saitoh
- Division of Infectious Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Sachiko Akashi
- Division of Infectious Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Takenao Yamada
- Department of Medical Technology and Science, Osaka University, Osaka, Japan
| | - Natsuko Tanimura
- Department of Medical Technology and Science, Osaka University, Osaka, Japan
| | - Fumi Matsumoto
- Department of Medical Technology and Science, Osaka University, Osaka, Japan
| | - Koichi Fukase
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan
| | - Shoichi Kusumoto
- Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan
| | - Atsushi Kosugi
- Department of Medical Technology and Science, Osaka University, Osaka, Japan, CREST, Japan Science and Technology Corporation, Tokyo, Japan
| | - Kensuke Miyake
- Division of Infectious Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan, -tokyo.ac.jp, CREST, Japan Science and Technology Corporation, Tokyo, Japan
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Kusumoto S, Fukase K, Fukase Y, Kataoka M, Yoshizaki H, Sato K, Oikawa M, Suda Y. Structural basis for endotoxic and antagonistic activities: investigation with novel synthetic lipid A analogs. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519030090060901] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Our early work using homogeneous synthetic preparations demonstrated the presence of a lipid A analog which antagonizes endotoxic activities of LPS and lipid A. The first example was a tetraacylated biosynthetic precursor, now known as precursor Ia or lipid IVa, that contains four 3-hydroxytetradecanoyl moieties linked to the bisphosphorylated disaccharide backbone common to the endotoxic hexa-acyl Escherichia coli lipid A. Various compounds with both endotoxic and antagonistic activities have subsequently been reported from either natural or synthetic sources, but little is known about the factors determining the type of the activities of the respective compounds. To approach this issue, we have synthesized a series of lipid A analogs with various numbers and chain lengths of acyl groups on the backbone. Some were prepared by the aid of a novel affinity separation procedure. The phosphate moieties were also synthetically replaced. Biological tests showed that at least three acyl groups are required for antagonistic activity but one or even both of the phosphates can be replaced with other acidic moieties without losing the activity. The effect of Kdo residues linked to lipid A is also briefly discussed. Molecular dynamics calculations reasonably explain possible conformations required for the biological activity.
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Affiliation(s)
- Shoichi Kusumoto
- Department of Chemistry, Graduate School of Science, Osaka University, Japan, -u.ac.jp
| | - Koichi Fukase
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
| | - Yoshiyuki Fukase
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
| | - Mikayo Kataoka
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
| | - Hiroaki Yoshizaki
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
| | - Kenjiro Sato
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
| | - Masato Oikawa
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
| | - Yasuo Suda
- Department of Chemistry, Graduate School of Science, Osaka University, Japan
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Kusumoto S, Fukase K, Oikawa M, Suda Y. Synthetic Chemistry and Function of Bacterial Cell Surface Glycoconjugates. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200200071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Fukase K, Fujimoto Y, Shimoyama A, Tanaka K. Synthesis of Bacterial Glycoconjugates and Their Bio-functional Studies in Innate Immunity. J SYN ORG CHEM JPN 2012. [DOI: 10.5059/yukigoseikyokaishi.70.113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Kusumoto S, Fukase K, Shiba T. Key structures of bacterial peptidoglycan and lipopolysaccharide triggering the innate immune system of higher animals: chemical synthesis and functional studies. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2010; 86:322-337. [PMID: 20431259 PMCID: PMC3417798 DOI: 10.2183/pjab.86.322] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 03/03/2010] [Indexed: 05/29/2023]
Abstract
Chemistry-based investigation is reviewed which led to identification of the active entities responsible for the immunostimulating potencies of peptidoglycan and lipopolysaccharide. Though these glycoconjugates which ubiquitously occur in wide range of bacteria as the essential components of their cell envelopes have long been known to enhance the immunological responses of higher animals, neither the precise chemical structures required nor the mechanism of their action had been [corrected] elucidated until early 1970s. Chemical synthesis of partial structures of peptidoglycan proved N-acetylmuramyl-L-alanyl-D-isoglutamine to be the minimum structure responsible for the activity and led to later identification of its receptor protein Nod2 present in animal cells. Another active partial structure of peptidoglycan, gamma-D-glutamyl-meso-diaminopimelic acid, and its receptor Nod1 were also identified as well. With regard to lipopolysaccharide, its glycolipid part named lipid A was purified and the structure studied. Chemically synthesized lipid A according to the newly elucidated structure exhibited full activity described for lipopolysaccharide known as endotoxin. Synthetic homogeneous lipid A and its structural analogues and labeled derivatives enabled precise studies of their interaction with receptor proteins and the mechanism of their action. Chemical synthesis of homogeneous partial structures of peptidoglycan and lipopolysaccharide gave unequivocal evidences for the concept that definite small molecular parts of these complex macromolecular bacterial glycoconjugates are specifically recognized by their respective receptors and trigger our defense system now widely recognized as innate immunity.
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Affiliation(s)
- Shoichi Kusumoto
- Suntory Institute for Bioorganic Research, Wakayamadai 1-1-1, Shimamotocho, Osaka, Japan.
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Kusumoto S. Synthesis and Functional Study of Bacterial Glycoconjugates Triggering the Innate Immune System of Higher Animals. TRENDS GLYCOSCI GLYC 2010. [DOI: 10.4052/tigg.22.107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kusumoto S, Fukase K. Synthesis of endotoxic principle of bacterial lipopolysaccharide and its recognition by the innate immune systems of hosts. CHEM REC 2007; 6:333-43. [PMID: 17304523 DOI: 10.1002/tcr.20098] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A new stage of endotoxin research was brought about by structure elucidation and chemical synthesis of lipid A, the lipophilic partial structure of the lipopolysaccharide (LPS) of Gram-negative bacteria. Synthetic lipid A exhibited full endotoxic activity, which gave unequivocal evidence for the concept that lipid A is the active entity of endotoxin. Various lipid A analogues, as well as their radiolabeled derivatives and more complex partial structures of LPS, were also synthesized. By the use of these synthetic homogeneous preparations, not only simple studies on structure-activity relationships but precise and detailed analyses became possible on how this typical bacterial component is recognized by the innate immune receptor complex of mammalian cells.
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Affiliation(s)
- Shoichi Kusumoto
- Suntory Institute for Bioorganic Research, 1-1-1 Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka 618-8503, Japan.
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Mitsuzawa H, Nishitani C, Hyakushima N, Shimizu T, Sano H, Matsushima N, Fukase K, Kuroki Y. Recombinant soluble forms of extracellular TLR4 domain and MD-2 inhibit lipopolysaccharide binding on cell surface and dampen lipopolysaccharide-induced pulmonary inflammation in mice. THE JOURNAL OF IMMUNOLOGY 2007; 177:8133-9. [PMID: 17114488 DOI: 10.4049/jimmunol.177.11.8133] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this study, we sought the possibility of a new therapeutic strategy for dampening endotoxin-induced inflammation using soluble form of extracellular rTLR4 domain (sTLR4) and soluble form of rMD-2 (sMD-2). Addition of sTLR4 plus sMD-2 was significantly effective in inhibiting LPS-elicited IL-8 release from U937 cells and NF-kappaB activation in the cells transfected with TLR4 and MD-2 when compared with a single treatment with sTLR4 or sMD-2. Thus, we investigated the role of the extracellular TLR4 domain in interaction of lipid A with MD-2. Biotinylated sTLR4 failed to coprecipitate [(3)H]lipid A when it was sedimented with streptavidin-agarose, demonstrating that the extracellular TLR4 domain does not directly bind lipid A by itself. The amounts of lipid A coprecipitated with sMD-2 significantly increased when coincubated with sTLR4, and sTLR4 increased the affinity of lipid A for the binding to sMD-2. Soluble CD14 is required for the sTLR4-stimulated increase of lipid A binding to sMD-2. We also found that addition of sTLR4 plus sMD-2 inhibited the binding of Alexa-conjugated LPS to the cells expressing TLR4 and MD-2. Murine lungs that had received sTLR4 plus sMD-2 with LPS did not show any findings indicative of interstitial edema, neutrophil flux, and hemorrhage. Co-instillation of sTLR4 plus sMD-2, but not sTLR4 or sMD-2 alone, significantly decreased neutrophil infiltration and TNF-alpha levels in bronchoalveolar lavage fluids from LPS-treated mice. This study provides novel usage of sTLR4 and sMD-2 as an antagonist against endotoxin-induced pulmonary inflammation.
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Affiliation(s)
- Hiroaki Mitsuzawa
- Department of Biochemistry, Sapporo Medical University School of Medicine, South-1 West-17, Chuo-ku, Sapporo 060-8556, Japan
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Akamatsu M, Fujimoto Y, Kataoka M, Suda Y, Kusumoto S, Fukase K. Synthesis of lipid A monosaccharide analogues containing acidic amino acid: exploring the structural basis for the endotoxic and antagonistic activities. Bioorg Med Chem 2006; 14:6759-77. [PMID: 16828560 DOI: 10.1016/j.bmc.2006.05.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 05/25/2006] [Accepted: 05/25/2006] [Indexed: 11/20/2022]
Abstract
For elucidation of the structural and conformational requirements on the endotoxic and antagonistic activity of lipid A derivatives, we designed and synthesized lipid A analogues containing acidic amino acid residues in place of the non-reducing end phosphorylated glucosamine. Definite switching of the endotoxic or antagonistic activity was observed depending on the difference of the acidic groups (phosphoric acid or carboxylic acid) in the lipid A analogues.
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Affiliation(s)
- Masao Akamatsu
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
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Kobayashi M, Saitoh SI, Tanimura N, Takahashi K, Kawasaki K, Nishijima M, Fujimoto Y, Fukase K, Akashi-Takamura S, Miyake K. Regulatory Roles for MD-2 and TLR4 in Ligand-Induced Receptor Clustering. THE JOURNAL OF IMMUNOLOGY 2006; 176:6211-8. [PMID: 16670331 DOI: 10.4049/jimmunol.176.10.6211] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
LPS, a principal membrane component in Gram-negative bacteria, is recognized by a receptor complex consisting of TLR4 and MD-2. MD-2 is an extracellular molecule that is associated with the extracellular domain of TLR4 and has a critical role in LPS recognition. MD-2 directly interacts with LPS, and the region from Phe(119) to Lys(132) (Arg(132) in mice) has been shown to be important for interaction between LPS and TLR4/MD-2. With mouse MD-2 mutants, we show in this study that Gly(59) was found to be a novel critical amino acid for LPS binding outside the region 119-132. LPS signaling is thought to be triggered by ligand-induced TLR4 clustering, which is also regulated by MD-2. Little is known, however, about a region or an amino acid in the MD-2 molecule that regulates ligand-induced receptor clustering. MD-2 mutants substituting alanine for Phe(126) or Gly(129) impaired LPS-induced TLR4 clustering, but not LPS binding to TLR4/MD-2, demonstrating that ligand-induced receptor clustering is differentially regulated by MD-2 from ligand binding. We further show that dissociation of ligand-induced receptor clustering and of ligand-receptor interaction occurs in a manner dependent on TLR4 signaling and requires endosomal acidification. These results support a principal role for MD-2 in LPS recognition.
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Affiliation(s)
- Makiko Kobayashi
- Division of Infectious Genetics, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan
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Fujimoto Y, Kimura E, Murata S, Kusumoto S, Fukase K. Synthesis and bioactivity of fluorescence- and biotin-labeled lipid A analogues for investigation of recognition mechanism in innate immunity. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2005.11.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Synthesis of lipid A analogues containing glucose instead of glucosamine and their LPS-antagonistic activities. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.03.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Akashi S, Saitoh SI, Wakabayashi Y, Kikuchi T, Takamura N, Nagai Y, Kusumoto Y, Fukase K, Kusumoto S, Adachi Y, Kosugi A, Miyake K. Lipopolysaccharide interaction with cell surface Toll-like receptor 4-MD-2: higher affinity than that with MD-2 or CD14. ACTA ACUST UNITED AC 2003; 198:1035-42. [PMID: 14517279 PMCID: PMC2194215 DOI: 10.1084/jem.20031076] [Citation(s) in RCA: 300] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Toll-like receptors (TLRs) are innate recognition molecules for microbial products, but their direct interactions with corresponding ligands remain unclarified. LPS, a membrane constituent of gram-negative bacteria, is the best-studied TLR ligand and is recognized by TLR4 and MD-2, a molecule associated with the extracellular domain of TLR4. Although TLR4-MD-2 recognizes LPS, little is known about the physical interaction between LPS and TLR4-MD-2. Here, we demonstrate cell surface LPS-TLR4-MD-2 complexes. CD14 greatly enhances the formation of LPS-TLR4-MD-2 complexes, but is not coprecipitated with LPS-TLR4-MD-2 complexes, suggesting a role for CD14 in LPS loading onto TLR4-MD-2 but not in the interaction itself between LPS and TLR4-MD-2. A tentative dissociation constant (Kd) for LPS-TLR4-MD-2 complexes was approximately 3 nM, which is approximately 10-20 times lower than the reported Kd for LPS-MD-2 or LPS-CD14. The presence of detergent disrupts LPS interaction with CD14 but not with TLR4-MD-2. E5531, a lipid A antagonist developed for therapeutic intervention of endotoxin shock, blocks LPS interaction with TLR4-MD-2 at a concentration 100 times lower than that required for blocking LPS interaction with CD14. These results reveal direct LPS interaction with cell surface TLR4-MD-2 that is distinct from that with MD-2 or CD14.
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Affiliation(s)
- Sachiko Akashi
- Division of Infectious Genetics, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minatoku, Tokyo 108-8639, Japan
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Fukase K, Ueno A, Fukase Y, Oikawa M, Suda Y, Kusumoto S. Synthesis and Biological Activities of Lipid A Analogs Possessingβ-Glycosidic Linkage at 1-Position. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2003. [DOI: 10.1246/bcsj.76.485] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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