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Kim HJ, Kim H, Lee JH, Hwangbo C. Toll-like receptor 4 (TLR4): new insight immune and aging. Immun Ageing 2023; 20:67. [PMID: 38001481 PMCID: PMC10668412 DOI: 10.1186/s12979-023-00383-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023]
Abstract
TLR4, a transmembrane receptor, plays a central role in the innate immune response. TLR4 not only engages with exogenous ligands at the cellular membrane's surface but also interacts with intracellular ligands, initiating intricate intracellular signaling cascades. Through MyD88, an adaptor protein, TLR4 activates transcription factors NF-κB and AP-1, thereby facilitating the upregulation of pro-inflammatory cytokines. Another adapter protein linked to TLR4, known as TRIF, autonomously propagates signaling pathways, resulting in heightened interferon expression. Recently, TLR4 has garnered attention as a significant factor in the regulation of symptoms in aging-related disorders. The persistent inflammatory response triggered by TLR4 contributes to the onset and exacerbation of these disorders. In addition, alterations in TLR4 expression levels play a pivotal role in modifying the manifestations of age-related diseases. In this review, we aim to consolidate the impact of TLR4 on cellular senescence and aging-related ailments, highlighting the potential of TLR4 as a novel therapeutic target that extends beyond immune responses.
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Affiliation(s)
- Hyo-Jin Kim
- Division of Life Science, College of Natural Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
- Division of Applied Life Science (BK21 Four), Research Institute of Life Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Hyemin Kim
- Division of Applied Life Science (BK21 Four), Research Institute of Life Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Jeong-Hyung Lee
- Department of Biochemistry (BK21 Four), College of Natural Sciences, Kangwon National University, Chuncheon, 24414, Republic of Korea
| | - Cheol Hwangbo
- Division of Life Science, College of Natural Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea.
- Division of Applied Life Science (BK21 Four), Research Institute of Life Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea.
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2
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Rivera CE, Zhou Y, Chupp DP, Yan H, Fisher AD, Simon R, Zan H, Xu Z, Casali P. Intrinsic B cell TLR-BCR linked coengagement induces class-switched, hypermutated, neutralizing antibody responses in absence of T cells. SCIENCE ADVANCES 2023; 9:eade8928. [PMID: 37115935 PMCID: PMC10146914 DOI: 10.1126/sciadv.ade8928] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 03/23/2023] [Indexed: 05/03/2023]
Abstract
Maturation of antibody responses entails somatic hypermutation (SHM), class-switch DNA recombination (CSR), plasma cell differentiation, and generation of memory B cells, and it is thought to require T cell help. We showed that B cell Toll-like receptor 4 (TLR4)-B cell receptor (BCR) (receptor for antigen) coengagement by 4-hydroxy-3-nitrophenyl acetyl (NP)-lipopolysaccharide (LPS) (Escherichia coli lipid A polysaccharide O-antigen) or TLR5-BCR coengagement by Salmonella flagellin induces mature antibody responses to NP and flagellin in Tcrβ-/-Tcrδ-/- and NSG/B mice. TLR-BCR coengagement required linkage of TLR and BCR ligands, "linked coengagement." This induced B cell CSR/SHM, germinal center-like differentiation, clonal expansion, intraconal diversification, plasma cell differentiation, and an anamnestic antibody response. In Tcrβ-/-Tcrδ-/- mice, linked coengagement of TLR4-BCR by LPS or TLR5-BCR by flagellin induced protective antibodies against E. coli or Salmonella Typhimurium. Our findings unveiled a critical role of B cell TLRs in inducing neutralizing antibody responses, including those to microbial pathogens, without T cell help.
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Affiliation(s)
- Carlos E. Rivera
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
| | - Yulai Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
| | - Daniel P. Chupp
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
| | - Hui Yan
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
| | - Amanda D. Fisher
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
| | - Raphael Simon
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Hong Zan
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
| | - Zhenming Xu
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
| | - Paolo Casali
- Department of Microbiology, Immunology & Molecular Genetics, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
- Department of Medicine, University of Texas Long School of Medicine, UT Health Science Center, San Antonio, TX 78229, USA
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3
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Uskoković V, Wu VM. Altering Microbiomes with Hydroxyapatite Nanoparticles: A Metagenomic Analysis. MATERIALS (BASEL, SWITZERLAND) 2022; 15:5824. [PMID: 36079205 PMCID: PMC9456825 DOI: 10.3390/ma15175824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
Hydroxyapatite (HAp), the most abundant biological material among mammals, has been recently demonstrated to possess moderate antibacterial properties. Metagenomics provides a series of tools for analyzing the simultaneous interaction of materials with larger communities of microbes, which may aid in optimizing the antibacterial activity of a material such as HAp. Here, a microbiome intrinsic to the sample of sandy soil collected from the base of an African Natal plum (Carissa macrocarpa) shrub surrounding the children's sandbox at the Arrowhead Park in Irvine, California was challenged with HAp nanoparticles and analyzed with next-generation sequencing for hypervariable 16S ribosomal DNA base pair homologies. HAp nanoparticles overwhelmingly reduced the presence of Gram-negative phyla, classes, orders, families, genera and species, and consequently elevated the relative presence of their Gram-positive counterparts. Thermodynamic, electrostatic and chemical bonding arguments were combined in a model proposed to explain this selective affinity. The ability of amphiphilic surface protrusions of lipoteichoic acid in Gram-positive bacteria and mycolic acid in mycobacteria to increase the dispersibility of the bacterial cells and assist in their resistance to capture by the solid phase is highlighted. Within the Gram-negative group, the variability of the distal, O-antigen portion of the membrane lipopolysaccharide was shown to be excessive and the variability of its proximal, lipid A portion insufficient to explain the selectivity based on chemical sequence arguments. Instead, flagella-driven motility proves to be a factor favoring the evasion of binding to HAp. HAp displayed a preference toward binding to less pathogenic bacteria than those causative of disease in humans, while taxa having a positive agricultural effect were largely captured by HAp, indicating an evolutionary advantage this may have given it as a biological material. The capacity to selectively sequester Gram-negative microorganisms and correspondingly alter the composition of the microbiome may open up a new avenue in environmental and biomedical applications of HAp.
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Affiliation(s)
- Vuk Uskoković
- TardigradeNano LLC, Irvine, CA 92604, USA;
- Department of Mechanical Engineering, San Diego State University, San Diego, CA 92182, USA
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4
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Brinkmann S, Spohn MS, Schäberle TF. Bioactive natural products from Bacteroidetes. Nat Prod Rep 2022; 39:1045-1065. [PMID: 35315462 DOI: 10.1039/d1np00072a] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Covering: up to end of January 2022Bacteria representing the phylum Bacteroidetes produce a diverse range of natural products, including polyketides, peptides and lactams. Here, we discuss unique aspects of the bioactive compounds discovered thus far, and the corresponding biosynthetic pathways if known, providing a comprehensive overview of the Bacteroidetes as a natural product reservoir.
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Affiliation(s)
- Stephan Brinkmann
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany.
| | - Marius S Spohn
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany.
| | - Till F Schäberle
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany. .,Institute for Insect Biotechnology, Justus Liebig University of Giessen, 35392 Giessen, Germany.,German Centre for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Giessen, Germany
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5
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Nichols FC, Bhuse K, Clark RB, Provatas AA, Carrington E, Wang YH, Zhu Q, Davey ME, Dewhirst FE. Serine/Glycine Lipid Recovery in Lipid Extracts From Healthy and Diseased Dental Samples: Relationship to Chronic Periodontitis. FRONTIERS IN ORAL HEALTH 2022; 2:698481. [PMID: 35048038 PMCID: PMC8757817 DOI: 10.3389/froh.2021.698481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/10/2021] [Indexed: 12/04/2022] Open
Abstract
Toll-like receptor 2 (TLR2) activation has been implicated in the pathogenesis of periodontal disease but the identity of the TLR2 agonists has been an evolving story. The serine/glycine lipids produced by Porphyromonas gingivalis are reported to engage human TLR2 and will promote the production of potent pro-inflammatory cytokines. This investigation compared the recovery of serine/glycine lipids in periodontal organisms, teeth, subgingival calculus, subgingival plaque, and gingival tissues, either from healthy sites or periodontally diseased sites. Lipids were extracted using the phospholipid extraction procedure of Bligh and Dyer and were analyzed using liquid chromatography/mass spectrometry for all serine/glycine lipid classes identified to date in P. gingivalis. Two serine/glycine lipid classes, Lipid 567 and Lipid 1256, were the dominant serine/glycine lipids recovered from oral Bacteroidetes bacteria and from subgingival calculus samples or diseased teeth. Lipid 1256 was the most abundant serine/glycine lipid class in lipid extracts from P. gingivalis, Tannerella forsythia, and Prevotella intermedia whereas Lipid 567 was the most abundant serine/glycine lipid class recovered in Capnocytophaga species and Porphyromonas endodontalis. Serine/glycine lipids were not detected in lipid extracts from Treponema denticola, Aggregatibacter actinomycetemcomitans, or Fusobacterium nucleatum. Lipid 1256 was detected more frequently and at a significantly higher mean level in periodontitis tissue samples compared with healthy/gingivitis tissue samples. By contrast, Lipid 567 levels were essentially identical. This report shows that members of the Bacteroidetes phylum common to periodontal disease sites produce Lipid 567 and Lipid 1256, and these lipids are prevalent in lipid extracts from subgingival calculus and from periodontally diseased teeth and diseased gingival tissues.
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Affiliation(s)
- Frank C Nichols
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, United States
| | - Kruttika Bhuse
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, United States
| | - Robert B Clark
- Departments of Immunology and Medicine, University of Connecticut School of Medicine, Farmington, CT, United States
| | - Anthony A Provatas
- Center for Environmental Sciences and Engineering, University of Connecticut, Storrs, CT, United States
| | - Elena Carrington
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, United States
| | - Yu-Hsiung Wang
- Department of Craniofacial Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, United States
| | - Qiang Zhu
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT, United States
| | - Mary E Davey
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, United States
| | - Floyd E Dewhirst
- Department of Microbiology, The Forsyth Institute, Cambridge, MA, United States.,Department of Oral Medicine, Harvard School of Dental Medicine, Infection and Immunity, Boston, MA, United States
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Bill MK, Brinkmann S, Oberpaul M, Patras MA, Leis B, Marner M, Maitre MP, Hammann PE, Vilcinskas A, Schuler SMM, Schäberle TF. Novel Glycerophospholipid, Lipo- and N-acyl Amino Acids from Bacteroidetes: Isolation, Structure Elucidation and Bioactivity. Molecules 2021; 26:5195. [PMID: 34500631 PMCID: PMC8433624 DOI: 10.3390/molecules26175195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/22/2021] [Accepted: 08/25/2021] [Indexed: 12/27/2022] Open
Abstract
The 'core' metabolome of the Bacteroidetes genus Chitinophaga was recently discovered to consist of only seven metabolites. A structural relationship in terms of shared lipid moieties among four of them was postulated. Here, structure elucidation and characterization via ultra-high resolution mass spectrometry (UHR-MS) and nuclear magnetic resonance (NMR) spectroscopy of those four lipids (two lipoamino acids (LAAs), two lysophosphatidylethanolamines (LPEs)), as well as several other undescribed LAAs and N-acyl amino acids (NAAAs), identified during isolation were carried out. The LAAs represent closely related analogs of the literature-known LAAs, such as the glycine-serine dipeptide lipids 430 (2) and 654. Most of the here characterized LAAs (1, 5-11) are members of a so far undescribed glycine-serine-ornithine tripeptide lipid family. Moreover, this study reports three novel NAAAs (N-(5-methyl)hexanoyl tyrosine (14) and N-(7-methyl)octanoyl tyrosine (15) or phenylalanine (16)) from Olivibacter sp. FHG000416, another Bacteroidetes strain initially selected as best in-house producer for isolation of lipid 430. Antimicrobial profiling revealed most isolated LAAs (1-3) and the two LPE 'core' metabolites (12, 13) active against the Gram-negative pathogen M. catarrhalis ATCC 25238 and the Gram-positive bacterium M. luteus DSM 20030. For LAA 1, additional growth inhibition activity against B. subtilis DSM 10 was observed.
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Affiliation(s)
- Mona-Katharina Bill
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
| | - Stephan Brinkmann
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
| | - Markus Oberpaul
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
| | - Maria A. Patras
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
| | - Benedikt Leis
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
| | - Michael Marner
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
| | | | - Peter E. Hammann
- Sanofi-Aventis Deutschland GmbH, R&D, 65926 Frankfurt am Main, Germany;
- Evotec International GmbH, 37079 Göttingen, Germany
| | - Andreas Vilcinskas
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
- Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, 35392 Giessen, Germany
| | | | - Till F. Schäberle
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, 35392 Giessen, Germany; (M.-K.B.); (S.B.); (M.O.); (M.A.P.); (B.L.); (M.M.); (A.V.)
- Institute for Insect Biotechnology, Justus-Liebig-University of Giessen, 35392 Giessen, Germany
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7
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Schneider YKH, Ø. Hansen K, Isaksson J, Ullsten S, H. Hansen E, Hammer Andersen J. Anti-Bacterial Effect and Cytotoxicity Assessment of Lipid 430 Isolated from Algibacter sp. Molecules 2019; 24:molecules24213991. [PMID: 31694159 PMCID: PMC6864645 DOI: 10.3390/molecules24213991] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/30/2019] [Accepted: 11/04/2019] [Indexed: 12/14/2022] Open
Abstract
Two bacterial isolates from the Barents Sea, both belonging to the genus Algibacter, were found to yield extracts with anti-bacterial bioactivity. Mass spectrometry guided dereplication and purification of the active extracts lead to the isolation of the same active principle in both extracts. The structure of the bioactive compound was identified via mass spectrometry and nuclear resonance spectroscopy and it turned out to be the known lipopeptide Lipid 430. We discovered and determined its previously unknown anti-bacterial activity against Streptococcus agalactiae and revealed a cytotoxic effect against the A2058 human melanoma cell line at significantly lower concentrations compared to its anti-bacterial concentration. Flow cytometry and microscopy investigations of the cytotoxicity against the melanoma cell line indicated that Lipid 430 did not cause immediate cell lysis. The experiments with melanoma cells suggest that the compound functions trough more complex pathways than acting as a simple detergent.
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Affiliation(s)
- Yannik K.-H. Schneider
- Marbio, Faculty for Fisheries, Biosciences and Economy, UiT—The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway (S.U.); (E.H.H.); (J.H.A.)
- Correspondence: ; Tel.: +47-77649267
| | - Kine Ø. Hansen
- Marbio, Faculty for Fisheries, Biosciences and Economy, UiT—The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway (S.U.); (E.H.H.); (J.H.A.)
| | - Johan Isaksson
- Department of Chemistry, Faculty of Natural Sciences, UiT—The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway;
| | - Sara Ullsten
- Marbio, Faculty for Fisheries, Biosciences and Economy, UiT—The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway (S.U.); (E.H.H.); (J.H.A.)
| | - Espen H. Hansen
- Marbio, Faculty for Fisheries, Biosciences and Economy, UiT—The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway (S.U.); (E.H.H.); (J.H.A.)
| | - Jeanette Hammer Andersen
- Marbio, Faculty for Fisheries, Biosciences and Economy, UiT—The Arctic University of Norway, Breivika, N-9037 Tromsø, Norway (S.U.); (E.H.H.); (J.H.A.)
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Are Sphingolipids and Serine Dipeptide Lipids Underestimated Virulence Factors of Porphyromonas gingivalis? Infect Immun 2018; 86:IAI.00035-18. [PMID: 29632248 DOI: 10.1128/iai.00035-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The keystone periodontal pathogen Porphyromonas gingivalis produces phosphorylated dihydroceramide lipids (sphingolipids) such as phosphoethanolamine dihydroceramide (PE DHC) and phosphoglycerol dihydroceramide (PG DHC) lipids. Phosphorylated DHCs (PDHCs) from P. gingivalis can affect a number of mammalian cellular functions, such as potentiation of prostaglandin secretion from gingival fibroblasts, promotion of RANKL-induced osteoclastogenesis, promotion of apoptosis, and enhancement of autoimmunity. In P. gingivalis, these lipids affect anchoring of surface polysaccharides, resistance to oxidative stress, and presentation of surface polysaccharides (anionic polysaccharides and K-antigen capsule). In addition to phosphorylated dihydroceramide lipids, serine dipeptide lipids of P. gingivalis are implicated in alveolar bone loss in chronic periodontitis through interference with osteoblast differentiation and function and promotion of osteoclast activity. As a prerequisite for designation as bacterial virulence factors, bacterial sphingolipids and serine dipeptide lipids are recovered in gingival/periodontal tissues, tooth calculus, human blood, vascular tissues, and brain. In addition to P. gingivalis, other bacteria of the genera Bacteroides, Parabacteroides, Porphyromonas, Tannerella, and Prevotella produce sphingolipids and serine dipeptide lipids. The contribution of PDHCs and serine dipeptide lipids to the pathogenesis of periodontal and extraoral diseases may be an underappreciated area in microbe-host interaction and should be more intensively investigated.
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Balas L, Feillet-Coudray C, Durand T. Branched Fatty Acyl Esters of Hydroxyl Fatty Acids (FAHFAs), Appealing Beneficial Endogenous Fat against Obesity and Type-2 Diabetes. Chemistry 2018; 24:9463-9476. [DOI: 10.1002/chem.201800853] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Indexed: 01/15/2023]
Affiliation(s)
- Laurence Balas
- Institut des Biomolécules Max Mousseron, IBMM; Université de Montpellier; CNRS, ENSCM; Faculté de Pharmacie; 15 av Charles Flahault, BP 14491 F-34093 Montpellier Cedex 05 France
| | | | - Thierry Durand
- Institut des Biomolécules Max Mousseron, IBMM; Université de Montpellier; CNRS, ENSCM; Faculté de Pharmacie; 15 av Charles Flahault, BP 14491 F-34093 Montpellier Cedex 05 France
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10
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Vidya MK, Kumar VG, Sejian V, Bagath M, Krishnan G, Bhatta R. Toll-like receptors: Significance, ligands, signaling pathways, and functions in mammals. Int Rev Immunol 2017; 37:20-36. [PMID: 29028369 DOI: 10.1080/08830185.2017.1380200] [Citation(s) in RCA: 275] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This review attempts to cover the implication of the toll-like receptors (TLRs) in controlling immune functions with emphasis on their significance, function, regulation and expression patterns. The tripartite TLRs are type I integral transmembrane receptors that are involved in recognition and conveying of pathogens to the immune system. These paralogs are located on cell surfaces or within endosomes. The TLRs are found to be functionally involved in the recognition of self and non-self-antigens, maturation of DCs and initiation of antigen-specific adaptive immune responses as they bridge the innate and adaptive immunity. Interestingly, they also have a significant role in immunotherapy and vaccination. Signals generated by TLRs are transduced through NFκB signaling and MAP kinases pathway to recruit pro-inflammatory cytokines and co-stimulatory molecules, which promote inflammatory responses. The excess production of these cytokines leads to grave systemic disorders like tumor growth and autoimmune disorders. Hence, regulation of the TLR signaling pathway is necessary to keep the host system safe. Many molecules like LPS, SOCS1, IRAK1, NFκB, and TRAF3 are involved in modulating the TLR pathways to induce appropriate response. Though quantification of these TLRs helps in correlating the magnitude of immune response exhibited by the animal, there are several internal, external, genetic and animal factors that affect their expression patterns. So it can be concluded that any identification based on those expression profiles may lead to improper diagnosis during certain conditions.
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Affiliation(s)
- Mallenahally Kusha Vidya
- a Department of Veterinary Biochemistry , Veterinary College, Karnataka Veterinary Animal and Fisheries Sciences University , Hebbal, Bangalore , Karnataka , India.,b Animal Physiology Division , ICAR-National Institute of Animal Nutrition and Physiology , Adugodi, Bangalore , Karnataka , India
| | - V Girish Kumar
- a Department of Veterinary Biochemistry , Veterinary College, Karnataka Veterinary Animal and Fisheries Sciences University , Hebbal, Bangalore , Karnataka , India
| | - Veerasamy Sejian
- b Animal Physiology Division , ICAR-National Institute of Animal Nutrition and Physiology , Adugodi, Bangalore , Karnataka , India
| | - Madiajagan Bagath
- b Animal Physiology Division , ICAR-National Institute of Animal Nutrition and Physiology , Adugodi, Bangalore , Karnataka , India
| | - Govindan Krishnan
- b Animal Physiology Division , ICAR-National Institute of Animal Nutrition and Physiology , Adugodi, Bangalore , Karnataka , India
| | - Raghavendra Bhatta
- b Animal Physiology Division , ICAR-National Institute of Animal Nutrition and Physiology , Adugodi, Bangalore , Karnataka , India
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11
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Nemati R, Dietz C, Anstadt EJ, Cervantes J, Liu Y, Dewhirst FE, Clark RB, Finegold S, Gallagher JJ, Smith MB, Yao X, Nichols FC. Deposition and hydrolysis of serine dipeptide lipids of Bacteroidetes bacteria in human arteries: relationship to atherosclerosis. J Lipid Res 2017; 58:1999-2007. [PMID: 28814639 DOI: 10.1194/jlr.m077792] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/17/2017] [Indexed: 11/20/2022] Open
Abstract
Multiple reaction monitoring-MS analysis of lipid extracts from human carotid endarterectomy and carotid artery samples from young individuals consistently demonstrated the presence of bacterial serine dipeptide lipid classes, including Lipid 654, an agonist for human and mouse Toll-like receptor (TLR)2, and Lipid 430, the deacylated product of Lipid 654. The relative levels of Lipid 654 and Lipid 430 were also determined in common oral and intestinal bacteria from the phylum Bacteroidetes and human serum and brain samples from healthy adults. The median Lipid 430/Lipid 654 ratio observed in carotid endarterectomy samples was significantly higher than the median ratio in lipid extracts of common oral and intestinal Bacteroidetes bacteria, and serum and brain samples from healthy subjects. More importantly, the median Lipid 430/Lipid 654 ratio was significantly elevated in carotid endarterectomies when compared with control artery samples. Our results indicate that deacylation of Lipid 654 to Lipid 430 likely occurs in diseased artery walls due to phospholipase A2 enzyme activity. These results suggest that commensal Bacteriodetes bacteria of the gut and the oral cavity may contribute to the pathogenesis of TLR2-dependent atherosclerosis through serine dipeptide lipid deposition and metabolism in artery walls.
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Affiliation(s)
- Reza Nemati
- Department of Chemistry University of Connecticut, Storrs, CT 06269
| | | | - Emily J Anstadt
- Department of Immunology and Medicine, University of Connecticut School of Medicine, Farmington, CT 06030
| | - Jorge Cervantes
- Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905
| | - Yaling Liu
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030
| | - Floyd E Dewhirst
- Department of Microbiology, The Forsyth Institute, Cambridge, MA 02142 and Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA 02115
| | - Robert B Clark
- Department of Immunology and Medicine, University of Connecticut School of Medicine, Farmington, CT 06030
| | - Sydney Finegold
- Infectious Disease Division, Veterans Affairs Medical Center, Los Angeles, CA 90073 and Departments of Medicine and Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, CA 90024
| | | | - Michael B Smith
- Department of Chemistry University of Connecticut, Storrs, CT 06269
| | - Xudong Yao
- Department of Chemistry University of Connecticut, Storrs, CT 06269.,Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Frank C Nichols
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030
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12
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Garrett TA. Major roles for minor bacterial lipids identified by mass spectrometry. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:1319-1324. [PMID: 27760388 DOI: 10.1016/j.bbalip.2016.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 01/31/2023]
Abstract
Mass spectrometry of lipids, especially those isolated from bacteria, has ballooned over the past two decades, affirming in the process the complexity of the lipidome. With this has come the identification of new and interesting lipid structures. Here is an overview of several novel lipids, from both Gram-negative and Gram-positive bacteria with roles in health and disease, whose structural identification was facilitated using mass spectrometry. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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Affiliation(s)
- Teresa A Garrett
- Department of Chemistry, Vassar College, 124 Raymond Avenue, Poughkeepsie, NY 12604, United States.
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13
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Molteni M, Gemma S, Rossetti C. The Role of Toll-Like Receptor 4 in Infectious and Noninfectious Inflammation. Mediators Inflamm 2016; 2016:6978936. [PMID: 27293318 PMCID: PMC4887650 DOI: 10.1155/2016/6978936] [Citation(s) in RCA: 279] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/04/2016] [Indexed: 12/13/2022] Open
Abstract
Toll-like receptor 4 (TLR4) belongs to the family of pattern recognition receptors (PRRs). They are highly conserved receptors that recognize conserved pathogen-associated molecular patterns (PAMPs), thus representing the first line of defense against infections. TLR4 has been long recognized as the sensing receptor for gram-negative lipopolysaccharide (LPS). In addition, it also binds endogenous molecules produced as a result of tissue injury. Hence, TLR4 represents a key receptor on which both infectious and noninfectious stimuli converge to induce a proinflammatory response. TLR4-mediated inflammation, triggered by exogenous or endogenous ligands, is also involved in several acute and chronic diseases, having a pivotal role as amplifier of the inflammatory response. This review focuses on the research progress about the role of TLR4 activation in infectious and noninfectious (e.g., sterile) inflammation and the effects of TLR4 signaling in some pathological conditions.
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Affiliation(s)
- Monica Molteni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
| | - Sabrina Gemma
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
| | - Carlo Rossetti
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
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14
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Lonez C, Irvine KL, Pizzuto M, Schmidt BI, Gay NJ, Ruysschaert JM, Gangloff M, Bryant CE. Critical residues involved in Toll-like receptor 4 activation by cationic lipid nanocarriers are not located at the lipopolysaccharide-binding interface. Cell Mol Life Sci 2015; 72:3971-82. [PMID: 25956320 PMCID: PMC4575701 DOI: 10.1007/s00018-015-1915-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/31/2015] [Accepted: 04/23/2015] [Indexed: 12/05/2022]
Abstract
DiC14-amidine is a cationic lipid that was originally designed as a lipid nanocarrier for nucleic acid transport, and turned out to be a Toll-like receptor 4 (TLR4) agonist as well. We found that while E. coli lipopolysaccharide (LPS) is a TLR4 agonist in all species, diC14-amidine nanoliposomes are full agonists for human, mouse and cat receptors but weak horse agonists. Taking advantage of this unusual species specificity, we used chimeric constructs based on the human and horse sequences and identified two regions in the human TLR4 that modulate the agonist activity of diC14-amidine. Interestingly, these regions lie outside the known LPS-binding domain. Competition experiments also support our hypothesis that diC14-amidine interacts primarily with TLR4 hydrophobic crevices located at the edges of the TLR4/TLR4* dimerization interface. We have characterized potential binding modes using molecular docking analysis and suggest that diC14-amidine nanoliposomes activate TLR4 by facilitating its dimerization in a process that is myeloid differentiation 2 (MD-2)-dependent and cluster of differentiation 14 (CD14)-independent. Our data suggest that TLR4 may be activated through binding at different anchoring points, expanding the repertoire of TLR4 ligands to non-MD-2-binding lipids.
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Affiliation(s)
- Caroline Lonez
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
- Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium.
| | - Kate L Irvine
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Malvina Pizzuto
- Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium
| | - Boris I Schmidt
- Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium
| | - Nick J Gay
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Jean-Marie Ruysschaert
- Structure and Function of Biological Membranes, Université Libre de Bruxelles, Brussels, Belgium
| | - Monique Gangloff
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Clare E Bryant
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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15
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Zähringer U, Ittig S, Lindner B, Moll H, Schombel U, Gisch N, Cornelis GR. NMR-based structural analysis of the complete rough-type lipopolysaccharide isolated from Capnocytophaga canimorsus. J Biol Chem 2014; 289:23963-76. [PMID: 24993825 DOI: 10.1074/jbc.m114.571489] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We here describe the NMR analysis of an intact lipopolysaccharide (LPS, endotoxin) in water with 1,2-dihexanoyl-sn-glycero-3-phosphocholine as detergent. When HPLC-purified rough-type LPS of Capnocytophaga canimorsus was prepared, (13)C,(15)N labeling could be avoided. The intact LPS was analyzed by homonuclear ((1)H) and heteronuclear ((1)H,(13)C, and (1)H,(31)P) correlated one- and two-dimensional NMR techniques as well as by mass spectrometry. It consists of a penta-acylated lipid A with an α-linked phosphoethanolamine attached to C-1 of GlcN (I) in the hybrid backbone, lacking the 4'-phosphate. The hydrophilic core oligosaccharide was found to be a complex hexasaccharide with two mannose (Man) and one each of 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo), Gal, GalN, and l-rhamnose residues. Position 4 of Kdo is substituted by phosphoethanolamine, also present in position 6 of the branched Man(I) residue. This rough-type LPS is exceptional in that all three negative phosphate residues are "masked" by positively charged ethanolamine substituents, leading to an overall zero net charge, which has so far not been observed for any other LPS. In biological assays, the corresponding isolated lipid A was found to be endotoxically almost inactive. By contrast, the intact rough-type LPS described here expressed a 20,000-fold increased endotoxicity, indicating that the core oligosaccharide significantly contributes to the endotoxic potency of the whole rough-type C. canimorsus LPS molecule. Based on these findings, the strict view that lipid A alone represents the toxic center of LPS needs to be reassessed.
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Affiliation(s)
- Ulrich Zähringer
- From the Division of Immunochemistry/Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a, 23845 Borstel, Germany,
| | - Simon Ittig
- Infection Biology, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland, and
| | - Buko Lindner
- From the Division of Immunochemistry/Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a, 23845 Borstel, Germany
| | - Hermann Moll
- From the Division of Immunochemistry/Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a, 23845 Borstel, Germany
| | - Ursula Schombel
- From the Division of Immunochemistry/Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a, 23845 Borstel, Germany
| | - Nicolas Gisch
- From the Division of Immunochemistry/Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a, 23845 Borstel, Germany
| | - Guy R Cornelis
- Infection Biology, Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland, and the Department of Biology, University of Namur, B5000 Namur, Belgium
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16
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Lonez C, Bessodes M, Scherman D, Vandenbranden M, Escriou V, Ruysschaert JM. Cationic lipid nanocarriers activate Toll-like receptor 2 and NLRP3 inflammasome pathways. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2014; 10:775-82. [DOI: 10.1016/j.nano.2013.12.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 12/12/2013] [Indexed: 01/31/2023]
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17
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Serine lipids of Porphyromonas gingivalis are human and mouse Toll-like receptor 2 ligands. Infect Immun 2013; 81:3479-89. [PMID: 23836823 DOI: 10.1128/iai.00803-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The total cellular lipids of Porphyromas gingivalis, a known periodontal pathogen, were previously shown to promote dendritic cell activation and inhibition of osteoblasts through engagement of Toll-like receptor 2 (TLR2). The purpose of the present investigation was to fractionate all lipids of P. gingivalis and define which lipid classes account for the TLR2 engagement, based on both in vitro human cell assays and in vivo studies in mice. Specific serine-containing lipids of P. gingivalis, called lipid 654 and lipid 430, were identified in specific high-performance liquid chromatography fractions as the TLR2-activating lipids. The structures of these lipids were defined using tandem mass spectrometry and nuclear magnetic resonance methods. In vitro, both lipid 654 and lipid 430 activated TLR2-expressing HEK cells, and this activation was inhibited by anti-TLR2 antibody. In contrast, TLR4-expressing HEK cells failed to be activated by either lipid 654 or lipid 430. Wild-type (WT) or TLR2-deficient (TLR2(-/-)) mice were injected with either lipid 654 or lipid 430, and the effects on serum levels of the chemokine CCL2 were measured 4 h later. Administration of either lipid 654 or lipid 430 to WT mice resulted in a significant increase in serum CCL2 levels; in contrast, the administration of lipid 654 or lipid 430 to TLR2(-/-) mice resulted in no increase in serum CCL2. These results thus identify a new class of TLR2 ligands that are produced by P. gingivalis that likely play a significant role in mediating inflammatory responses both at periodontal sites and, potentially, in other tissues where these lipids might accumulate.
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Abstract
Pattern recognition receptors (PRRs) on host cells detect pathogens to activate innate immunity which, in turn, initiates inflammatory and adaptive immune responses. Successful activation of PRRs is, therefore, critical to controlling infections and driving pathogen‐specific adaptive immunity, but overactivity of PRRs causes systemic inflammation, which is detrimental to the host. Here we review the PRR literature as it relates to horses and speculate on the role PRRs may play in sepsis and endotoxaemia.
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Affiliation(s)
- A H Werners
- Anatomy, Physiology and Pharmacology Academic Programme, School of Veterinary Medicine, St George's University, True Blue, Grenada, West Indies
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19
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Panter G, Jerala R. The ectodomain of the Toll-like receptor 4 prevents constitutive receptor activation. J Biol Chem 2011; 286:23334-44. [PMID: 21543336 DOI: 10.1074/jbc.m110.205419] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toll-like receptor 4 (TLR4) is involved in activation of the innate immune response in a large number of different diseases. Despite numerous studies, the role of separate domains of TLR4 in the regulation of receptor activation is poorly understood. Replacement of the TLR4 ectodomain with LPS-binding proteins MD-2 or CD14 resulted in a robust ligand-independent constitutive activation comparable with the maximal stimulation of the receptor with LPS. The same effect was achieved by the replacement of the ectodomain with a monomeric fluorescent protein or a 24-kDa gyrase B fragment. This demonstrates an intrinsic dimerization propensity of the transmembrane and cytoplasmic domains of TLR4 and reveals a previously unknown function of the ectodomain in inhibiting spontaneous receptor dimerization. Constitutive activation was abolished by the replacement of the ectodomain by a bulkier protein ovalbumin. N-terminal deletion variants of TLR4 revealed that the smallest segment of the ectodomain that already prevents constitutive activity comprises only 90 residues (542 to 631) of the total 608 residues. We conclude that TLR4 represents a receptor with a low threshold of activation that can be rapidly activated by the release of inhibition exerted by its ectodomain. This is important for the sensitivity of TLR4 to activation by different agonists. The TLR4 ectodomain has multiple roles in enabling ligand regulated activation, providing proper localization while serving as an inhibitor to prevent spontaneous, ligand-independent dimerization.
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Affiliation(s)
- Gabriela Panter
- Department of Biotechnology, National Institute of Chemistry, University of Ljubljana, 1000 Ljubljana, Slovenia
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20
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Tukhvatulin AI, Logunov DY, Shcherbinin DN, Shmarov MM, Naroditsky BS, Gudkov AV, Gintsburg AL. Toll-like receptors and their adapter molecules. BIOCHEMISTRY (MOSCOW) 2011; 75:1098-114. [PMID: 21077829 DOI: 10.1134/s0006297910090038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Toll-like receptors (TLR) are among key receptors of the innate mammalian immune system. Receptors of this family are able to recognize specific highly conserved molecular regions (patterns) in pathogen structures, thus initiating reactions of both innate and acquired immune response finally resulting in the elimination of the pathogen. In this case every individual TLR type is able to bind a broad spectrum of molecules of microbial origin characterized by different chemical properties and structures. Recent data demonstrate the existence of a multistep mechanism of the TLR recognition of the pathogen in which, in addition to receptors proper, the involvement of different adapter molecules is necessary. However, functions of separate adapter molecules as well as the principles of formation of a multicomponent system of ligand-specific recognition are still not quite understandable. We describe all identified as well as possible (candidate) adapter TLR molecules by giving their brief characteristics, and we also propose generalized possible variants of the TLR ligand-specific recognition with involvement of adapter molecules.
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Affiliation(s)
- A I Tukhvatulin
- Gamaleya Institute of Epidemiology and Microbiology, Russian Academy of Medical Sciences, Moscow, 123098, Russia.
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21
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Geiger O, González-Silva N, López-Lara IM, Sohlenkamp C. Amino acid-containing membrane lipids in bacteria. Prog Lipid Res 2010; 49:46-60. [DOI: 10.1016/j.plipres.2009.08.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Toll-like receptors (TLRs) and Nod-like receptors (NLRs) in inflammatory disorders. Semin Immunol 2009; 21:242-53. [PMID: 19748439 DOI: 10.1016/j.smim.2009.06.005] [Citation(s) in RCA: 217] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 06/30/2009] [Indexed: 12/15/2022]
Abstract
Toll-like receptors (TLRs) and Nod-like receptors (NLRs) are two major forms of innate immune sensors, which provide immediate responses against pathogenic invasion or tissue injury. Activation of these sensors induces the recruitment of innate immune cells such as macrophages and neutrophils, initiates tissue repair processes, and results in adaptive immune activation. Abnormalities in any of these innate sensor-mediated processes may cause excessive inflammation due to either hyper responsive innate immune signaling or sustained compensatory adaptive immune activation. Recent gene association studies appear to reveal strong associations of NLR gene mutations and development of several idiopathic inflammatory disorders. In contrast, TLR polymorphisms are less often associated with inflammatory disorders. Nevertheless, TLRs are up-regulated in the affected tissue of most inflammatory disorders, suggesting TLR signaling is involved in the pathogenesis of chronic and/or idiopathic inflammatory disorders. NLR signaling results in the formation of a molecular scaffold complex (termed an inflammasome) and orchestrates with TLRs to induce IL-1beta and IL-18, both of which are important mediators in the majority of inflammatory disorders. Therefore, understanding the roles of TLRs and NLRs in the pathogenesis of chronic and idiopathic inflammatory disorders may provide novel targets for the prevention and/or treatment of many common and uncommon diseases involving inflammation.
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23
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Greene CM, Branagan P, McElvaney NG. Toll-like receptors as therapeutic targets in cystic fibrosis. Expert Opin Ther Targets 2008; 12:1481-95. [DOI: 10.1517/14728220802515293] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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24
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Abstract
The Toll family of class I transmembrane receptors recognizes and responds to diverse structures associated with pathogenic microorganisms. These receptors mediate initial responses in innate immunity and are required for the development of the adaptive immune response. Toll receptor signaling pathways are also implicated in serious autoimmune diseases such as endotoxic shock and thus are important therapeutic targets. In this review we discuss how microbial structures as different as nucleic acids and lipoproteins can be recognized by the extracellular domains of Toll receptors. We review recent evidence that the mechanism of signal transduction is complex and involves sequential changes in the conformation of the receptor induced by binding of the ligand. Finally, we assess the emerging area of cross talk in the Toll pathways. Recent work suggests that signaling through TLR4 in response to endotoxin is modified by inputs from at least two other pathways acting through beta2 integrins and protein kinase Cepsilon.
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Affiliation(s)
- Nicholas J Gay
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom.
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25
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Gomi K, Kikuchi T, Tokue Y, Fujimura S, Uehara A, Takada H, Watanabe A, Nukiwa T. Mouse and human cell activation by N-dodecanoyl-DL-homoserine lactone, a Chromobacterium violaceum autoinducer. Infect Immun 2006; 74:7029-31. [PMID: 16982829 PMCID: PMC1698062 DOI: 10.1128/iai.00038-06] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chromobacterium violaceum produces autoinducers, including homoserine lactones (HSLs), for genetic regulation. Among the seven HSLs derived from C. violaceum we evaluated, only C(12)-HSL stimulated the production of inflammatory cytokines in mammalian monocytic cell lines through the activation of the NF-kappaB signaling pathway besides their quorum-sensing role, like 3-oxo-C(12)-HSL from Pseudomonas aeruginosa.
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Affiliation(s)
- Kazunori Gomi
- Department of Respiratory Oncology and Molecular Medicine, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-Ku, Sendai 980-8575, Japan.
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26
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Kawasaki K, Ernst RK, Miller SI. 3-O-deacylation of lipid A by PagL, a PhoP/PhoQ-regulated deacylase of Salmonella typhimurium, modulates signaling through Toll-like receptor 4. J Biol Chem 2004; 279:20044-8. [PMID: 15014080 DOI: 10.1074/jbc.m401275200] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toll-like receptor 4 (TLR4)-mediated responses, which are induced by the lipid A portion of lipopolysaccharide, are important for host defense against Salmonellae infection. A variety of different data indicate that the acylation state of lipid A can alter TLR4-mediated responses. The S. typhimurium virulence gene product PhoP/PhoQ signals the presence of host microenvironments to regulate the expression of a lipid A 3-O-deacylase, PagL, and a lipid A palmitoyltransferase, PagP. We now demonstrate that 3-O-deacylation and palmitoylation of lipid A decreases its ability to induce TLR4-mediated signaling. Deacylated lipid A, deacylated and palmitoylated lipid A, palmitoylated lipid A, and unmodified lipid A species were purified from Escherichia coli heterologously expressing PagL and/or PagP. The purified lipid A preparations showed spectra of a single lipid A species on mass spectrometry and gave a single band on thin layer chromatography. The activity of purified lipid A species was examined using human and mouse cell lines that express recombinant human TLR4. Compared with unmodified lipid A, the modified lipid A species are 30-100-fold less active in the ability to induce NF-kappaB-dependent reporter activation. These results suggest that the lipid A modifications reduce TLR4-signaling as part of Salmonellae adaptation to host environments.
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Affiliation(s)
- Kiyoshi Kawasaki
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
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27
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Abstract
Toll-like receptors (TLRs) are type I transmembrane proteins involved in innate immunity by recognizing microbial conserved structures. Recent studies have shown that TLR3 recognizes dsRNA, a viral product, whereas TLR9 recognizes unmethylated CpG motifs frequently found in the genome of bacteria and viruses, but not vertebrates. TLR7 recognizes small synthetic immune modifiers including imiquimod, R-848, loxoribine, and bropirimine, all of which are already applied or promising for clinical use against viral infections and cancers. Plasmacytoid dendritic cells express TLR7 and TLR9, and respond to TLR7 and TLR9 ligands by producing a large amount of interferon (IFN-alpha). These results indicate that TLR3, TLR7 and TLR9 may play an important role in detecting and combating viral infections.
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Affiliation(s)
- Shizuo Akira
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, SORST of Japan Science and Technology Corporation, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
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28
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Kawasaki K, Nogawa H, Nishijima M. Identification of mouse MD-2 residues important for forming the cell surface TLR4-MD-2 complex recognized by anti-TLR4-MD-2 antibodies, and for conferring LPS and taxol responsiveness on mouse TLR4 by alanine-scanning mutagenesis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:413-20. [PMID: 12496426 DOI: 10.4049/jimmunol.170.1.413] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The expression of MD-2, which associates with Toll-like receptor (TLR) 4 on the cell surface, confers LPS and LPS-mimetic Taxol responsiveness on TLR4. Alanine-scanning mutagenesis was performed to identify the mouse MD-2 residues important for conferring LPS and Taxol responsiveness on mouse TLR4, and for forming the cell surface TLR4-MD-2 complex recognized by anti-TLR4-MD-2 Ab MTS510. Single alanine mutations were introduced into mouse MD-2 (residues 17-160), and the mutants were expressed in a human cell line expressing mouse TLR4. Mouse MD-2 mutants, in which a single alanine mutation was introduced at Cys37, Leu71, Leu78, Cys95, Tyr102, Cys105, Glu111, Val113, Ile117, Pro118, Phe119, Glu136, Ile138, Leu146, Cys148, or Thr152, showed dramatically reduced ability to form the cell surface mouse TLR4-mouse MD-2 complex recognized by MTS510, and the mutants also showed reduced ability to confer LPS and Taxol responsiveness. In contrast, mouse MD-2 mutants, in which a single alanine mutation was introduced at Tyr34, Tyr36, Gly59, Val82, Ile85, Phe126, Pro127, Gly129, Ile153, Ile154, and His155 showed normal ability to form the cell surface mouse TLR4-mouse MD-2 complex recognized by MTS510, but their ability to confer LPS and Taxol responsiveness was apparently reduced. These results suggest that the ability of MD-2 to form the cell surface mouse TLR4-mouse MD-2 complex recognized by MTS510 is essential for conferring LPS and Taxol responsiveness on TLR4, but not sufficient. In addition, the required residues at codon numbers 34, 85, 101, 122, and 153 for the ability of mouse MD-2 to confer LPS responsiveness are partly different from those for Taxol responsiveness.
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MESH Headings
- Alanine/genetics
- Amino Acid Substitution/genetics
- Animals
- Antibodies, Monoclonal/metabolism
- Antigens, Ly/genetics
- Antigens, Ly/immunology
- Antigens, Ly/metabolism
- Antigens, Ly/physiology
- Aspartic Acid/genetics
- Cell Line
- Cell Membrane/genetics
- Cell Membrane/immunology
- Cell Membrane/metabolism
- Drosophila Proteins
- Glutamic Acid/genetics
- Humans
- Ligands
- Lipopolysaccharide Receptors/genetics
- Lipopolysaccharide Receptors/immunology
- Lipopolysaccharide Receptors/metabolism
- Lipopolysaccharide Receptors/physiology
- Lipopolysaccharides/metabolism
- Lipopolysaccharides/pharmacology
- Lymphocyte Antigen 96
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/metabolism
- Membrane Glycoproteins/physiology
- Mice
- Mutagenesis, Site-Directed
- Paclitaxel/metabolism
- Paclitaxel/pharmacology
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/immunology
- Receptors, Cell Surface/metabolism
- Receptors, Cell Surface/physiology
- Toll-Like Receptor 4
- Toll-Like Receptors
- Transfection
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Affiliation(s)
- Kiyoshi Kawasaki
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan
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29
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Kawai Y, Watanabe M, Matsuura M, Nishijima M, Kawahara K. The partially degraded lipopolysaccharide of Burkholderia cepacia and ornithine-containing lipids derived from some Gram-negative bacteria are useful complex lipid adjuvants. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2002; 34:173-9. [PMID: 12423768 DOI: 10.1111/j.1574-695x.2002.tb00621.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The partially degraded lipopolysaccharide of Burkholderia cepacia (LPSdegr) and the ornithine-containing lipids were purified from some bacteria. The substances were developed as complex lipid adjuvants, because they have weak toxicity and are able to activate the immune systems of the living body. After various toxoid antigens such as pertussis toxoid, diphtheria toxoid and tetanus toxoid were mixed with the complex lipid adjuvants, the mixtures were administered to mice subcutaneously. Antitoxoid IgG antibody titers in the serum were measured several times over 3 months. The efficacy of the LPSdegr as adjuvant was almost as high as that of the ornithine-containing lipids, and it was almost equal to that of the aluminum hydroxide adjuvant (Alum), which is generally used as a vaccine adjuvant.
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Affiliation(s)
- Yohko Kawai
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1, Toyama-cho, Shinjuku-ku, Tokyo 162-8640, Japan
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