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Huynh M, Crane MJ, Jamieson AM. The lung, the niche, and the microbe: Exploring the lung microbiome in cancer and immunity. Front Immunol 2023; 13:1094110. [PMID: 36733391 PMCID: PMC9888758 DOI: 10.3389/fimmu.2022.1094110] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/29/2022] [Indexed: 01/18/2023] Open
Abstract
The lung is a complex and unique organ system whose biology is strongly influenced by environmental exposure, oxygen abundance, connection to extrapulmonary systems via a dense capillary network, and an array of immune cells that reside in the tissue at steady state. The lung also harbors a low biomass community of commensal microorganisms that are dynamic during both health and disease with the capacity to modulate regulatory immune responses during diseases such as cancer. Lung cancer is the third most common cancer worldwide with the highest mortality rate amongst cancers due to the difficulty of an early diagnosis. This review discusses the current body of work addressing the interactions between the lung microbiota and the immune system, and how these two components of the pulmonary system are linked to lung cancer development and outcomes. Bringing in lessons from broader studies examining the effects of the gut microbiota on cancer outcomes, we highlight many challenges and gaps in this nascent field.
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Affiliation(s)
| | | | - Amanda M. Jamieson
- Department of Molecular Microbiology & Immunology, Brown University, Providence, RI, United States
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2
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Natural and synthetic carbohydrate-based vaccine adjuvants and their mechanisms of action. Nat Rev Chem 2021; 5:197-216. [PMID: 37117529 PMCID: PMC7829660 DOI: 10.1038/s41570-020-00244-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2020] [Indexed: 01/31/2023]
Abstract
Modern subunit vaccines based on homogeneous antigens offer more precise targeting and improved safety compared with traditional whole-pathogen vaccines. However, they are also less immunogenic and require an adjuvant to increase the immunogenicity of the antigen and potentiate the immune response. Unfortunately, few adjuvants have sufficient potency and low enough toxicity for clinical use, highlighting the urgent need for new, potent and safe adjuvants. Notably, a number of natural and synthetic carbohydrate structures have been used as adjuvants in clinical trials, and two have recently been approved in human vaccines. However, naturally derived carbohydrate adjuvants are heterogeneous, difficult to obtain and, in some cases, unstable. In addition, their molecular mechanisms of action are generally not fully understood, partly owing to the lack of tools to elucidate their immune-potentiating effects, thus hampering the rational development of optimized adjuvants. To address these challenges, modification of the natural product structure using synthetic chemistry emerges as an attractive approach to develop well-defined, improved carbohydrate-containing adjuvants and chemical probes for mechanistic investigation. This Review describes selected examples of natural and synthetic carbohydrate-based adjuvants and their application in synthetic self-adjuvanting vaccines, while also discussing current understanding of their molecular mechanisms of action.
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Kaewpitak A, Bauer CS, Seward EP, Boissonade FM, Douglas CWI. Porphyromonas gingivalis
lipopolysaccharide rapidly activates trigeminal sensory neurons and may contribute to pulpal pain. Int Endod J 2020; 53:846-858. [DOI: 10.1111/iej.13282] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 02/12/2020] [Indexed: 01/19/2023]
Affiliation(s)
- A. Kaewpitak
- School of Clinical Dentistry University of Sheffield Sheffield UK
| | - C. S. Bauer
- Department of Biomedical Science University of Sheffield Sheffield UK
| | - E. P. Seward
- Department of Biomedical Science University of Sheffield Sheffield UK
| | - F. M. Boissonade
- School of Clinical Dentistry University of Sheffield Sheffield UK
| | - C. W. I. Douglas
- School of Clinical Dentistry University of Sheffield Sheffield UK
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4
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Inflammasomes, Autophagy, and Cell Death: The Trinity of Innate Host Defense against Intracellular Bacteria. Mediators Inflamm 2019; 2019:2471215. [PMID: 30728749 PMCID: PMC6341260 DOI: 10.1155/2019/2471215] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/19/2018] [Indexed: 01/17/2023] Open
Abstract
Inflammasome activation is an innate host defense mechanism initiated upon sensing pathogens or danger in the cytosol. Both autophagy and cell death are cell autonomous processes important in development, as well as in host defense against intracellular bacteria. Inflammasome, autophagy, and cell death pathways can be activated by pathogens, pathogen-associated molecular patterns (PAMPs), cell stress, and host-derived damage-associated molecular patterns (DAMPs). Phagocytosis and toll-like receptor (TLR) signaling induce reactive oxygen species (ROS), type I IFN, NFκB activation of proinflammatory cytokines, and the mitogen-activated protein kinase cascade. ROS and IFNγ are also prominent inducers of autophagy. Pathogens, PAMPs, and DAMPs activate TLRs and intracellular inflammasomes, inducing apoptotic and inflammatory caspases in a context-dependent manner to promote various forms of cell death to eliminate pathogens. Common downstream signaling molecules of inflammasomes, autophagy, and cell death pathways interact to initiate appropriate measures against pathogens and determine host survival as well as pathological consequences of infection. The integration of inflammasome activation, autophagy, and cell death is central to pathogen clearance. Various pathogens produce virulence factors to control inflammasomes, subvert autophagy, and modulate host cell death in order to evade host defense. This review highlights the interaction of inflammasomes, autophagy, and host cell death pathways in counteracting Burkholderia pseudomallei, the causative agent of melioidosis. Contrasting evasion strategies used by B. pseudomallei, Mycobacterium tuberculosis, and Legionella pneumophila to avoid and dampen these innate immune responses will be discussed.
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5
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Ohto U. Conservation and Divergence of Ligand Recognition and Signal Transduction Mechanisms in Toll-Like Receptors. Chem Pharm Bull (Tokyo) 2017; 65:697-705. [PMID: 28768923 DOI: 10.1248/cpb.c17-00323] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Toll-like receptors (TLRs) play a central role in innate immunity as pathogen sensors. During the last decade, structural analyses of TLRs have revealed the mechanisms of ligand recognition and signal transduction. Each TLR recognizes its cognate ligand in a different manner, whereas signal transduction is achieved by a common mechanism. In this review, the mechanisms of ligand recognition and signal transduction by TLRs are summarized based on recent structural information.
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Affiliation(s)
- Umeharu Ohto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
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Rudbach J, Keegan D, Sowell C. Calculating therapeutic indices and therapeutic advantages for endotoxins and monophosphoryl lipid A: an evaluation of data from the scientific literature. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/096805199500200410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This review article addresses the question of whether or not monophosphoryl lipid A offers a therapeutic advantage over smaller doses of endotoxin. Biological data were collected from a literature review and these were used to calculate therapeutic indices for monophosphoryl lipid A and endotoxin. Subsequent calculations yielded results which showed that, in humans and in other animals, monophosphoryl lipid A did have a therapeutic advantage over smaller doses of endotoxin.
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Affiliation(s)
- J.A. Rudbach
- Ribi ImmunoChem Research, Inc., Hamilton, Montana, USA
| | - D.S. Keegan
- Ribi ImmunoChem Research, Inc., Hamilton, Montana, USA
| | - C.G. Sowell
- Ribi ImmunoChem Research, Inc., Hamilton, Montana, USA
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7
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Cardiolipins Act as a Selective Barrier to Toll-Like Receptor 4 Activation in the Intestine. Appl Environ Microbiol 2016; 82:4264-78. [PMID: 27208127 DOI: 10.1128/aem.00463-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/01/2016] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Intestinal homeostasis mechanisms must protect the host intestinal tissue from endogenous lipopolysaccharides (LPSs) produced by the intestinal microbiota. In this report, we demonstrate that murine intestinal fecal lipids effectively block Toll-like receptor 4 (TLR4) responses to naturally occurring Bacteroidetes sp. LPS. Cardiolipin (CL) represents a significant proportion of the total intestinal and fecal lipids and, furthermore, potently antagonizes TLR4 activation by reducing LPS binding at the lipopolysaccharide binding protein (LBP), CD14, and MD-2 steps of the TLR4 signaling pathway. It is further demonstrated that intestinal lipids and CL are less effective at neutralizing more potent Enterobacteriaceae-type LPS, which is enriched in feces obtained from mice with dextran sodium sulfate (DSS)-treated inflammatory bowel disease. The selective inhibition of naturally occurring LPS structures by intestinal lipids may represent a novel homeostasis mechanism that blocks LPS activation in response to symbiotic but not dysbiotic microbial communities. IMPORTANCE The guts of animals harbor a variety of Gram-negative bacteria associated with both states of intestinal health and states of disease. Environmental factors, such as dietary habits, can drive the microbial composition of the host animal's intestinal bacterial community toward a more pathogenic state. Both beneficial and harmful Gram-negative bacteria are capable of eliciting potentially damaging inflammatory responses from the host intestinal tissues via a lipopolysaccharide (LPS)-dependent pathway. Physical mucosal barriers and antibodies produced by the intestinal immune system protect against the undesired inflammatory effects of LPS, although it is unknown why some bacteria are more effective at overcoming the protective barriers than others. This report describes the discovery of a lipid-type protective barrier in the intestine that reduces the deleterious effects of LPSs from beneficial bacteria but is less effective in dampening the inflammatory effects of LPSs from harmful bacteria, providing a novel mechanistic insight into inflammatory intestinal disorders.
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Stromberg LR, Hengartner NW, Swingle KL, Moxley RA, Graves SW, Montaño GA, Mukundan H. Membrane Insertion for the Detection of Lipopolysaccharides: Exploring the Dynamics of Amphiphile-in-Lipid Assays. PLoS One 2016; 11:e0156295. [PMID: 27227979 PMCID: PMC4881986 DOI: 10.1371/journal.pone.0156295] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/12/2016] [Indexed: 12/27/2022] Open
Abstract
Shiga toxin-producing Escherichia coli is an important cause of foodborne illness, with cases attributable to beef, fresh produce and other sources. Many serotypes of the pathogen cause disease, and differentiating one serotype from another requires specific identification of the O antigen located on the lipopolysaccharide (LPS) molecule. The amphiphilic structure of LPS poses a challenge when using classical detection methods, which do not take into account its lipoglycan biochemistry. Typically, detection of LPS requires heat or chemical treatment of samples and relies on bioactivity assays for the conserved lipid A portion of the molecule. Our goal was to develop assays to facilitate the direct and discriminative detection of the entire LPS molecule and its O antigen in complex matrices using minimal sample processing. To perform serogroup identification of LPS, we used a method called membrane insertion on a waveguide biosensor, and tested three serogroups of LPS. The membrane insertion technique allows for the hydrophobic association of LPS with a lipid bilayer, where the exposed O antigen can be targeted for specific detection. Samples of beef lysate were spiked with LPS to perform O antigen specific detection of LPS from E. coli O157. To validate assay performance, we evaluated the biophysical interactions of LPS with lipid bilayers both in- and outside of a flow cell using fluorescence microscopy and fluorescently doped lipids. Our results indicate that membrane insertion allows for the qualitative and reliable identification of amphiphilic LPS in complex samples like beef homogenates. We also demonstrated that LPS-induced hole formation does not occur under the conditions of the membrane insertion assays. Together, these findings describe for the first time the serogroup-specific detection of amphiphilic LPS in complex samples using a membrane insertion assay, and highlight the importance of LPS molecular conformations in detection architectures.
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Affiliation(s)
- Loreen R. Stromberg
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico, United States of America
- Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- The New Mexico Consortium, Los Alamos, New Mexico, United States of America
| | - Nicolas W. Hengartner
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Kirstie L. Swingle
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Rodney A. Moxley
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Steven W. Graves
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico, United States of America
- The New Mexico Consortium, Los Alamos, New Mexico, United States of America
| | - Gabriel A. Montaño
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Harshini Mukundan
- Center for Biomedical Engineering, University of New Mexico, Albuquerque, New Mexico, United States of America
- Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
- The New Mexico Consortium, Los Alamos, New Mexico, United States of America
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9
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Haishima Y, Hasegawa C, Todoki K, Sasaki K, Niimi S, Ozono S. A biological study establishing the endotoxin limit of biomaterials for bone regeneration in cranial and femoral implantation of rats. J Biomed Mater Res B Appl Biomater 2016; 105:1514-1524. [DOI: 10.1002/jbm.b.33692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 03/15/2016] [Accepted: 04/06/2016] [Indexed: 01/25/2023]
Affiliation(s)
- Yuji Haishima
- Division of Medical Devices; National Institute of Health Sciences; 1-18-1 Kamiyoga Setagaya Tokyo 158-8501 Japan
| | - Chie Hasegawa
- Division of Medical Devices; National Institute of Health Sciences; 1-18-1 Kamiyoga Setagaya Tokyo 158-8501 Japan
| | - Kazuo Todoki
- Division of Oral Science & Pharmacology, Department of Dental Hygiene, School of Nursing; Kanagawa Dental University; 82 Inaoka-cho Yokosuka Kanagawa 238-8580 Japan
| | - Kazuo Sasaki
- R&D Center, NH Foods Ltd.; 3-3 Midorigahara Tsukuba Ibaraki 300-2646 Japan
| | - Shingo Niimi
- Division of Medical Devices; National Institute of Health Sciences; 1-18-1 Kamiyoga Setagaya Tokyo 158-8501 Japan
| | - Satoru Ozono
- Division of Medical Devices; National Institute of Health Sciences; 1-18-1 Kamiyoga Setagaya Tokyo 158-8501 Japan
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10
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McHugh KJ, Guarecuco R, Langer R, Jaklenec A. Single-injection vaccines: Progress, challenges, and opportunities. J Control Release 2015; 219:596-609. [PMID: 26254198 DOI: 10.1016/j.jconrel.2015.07.029] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 01/01/2023]
Abstract
Currently, vaccination is the most efficient and cost-effective medical treatment for infectious diseases; however, each year 10 million infants remain underimmunized due to current vaccination schedules that require multiple doses to be administered across months or years. These dosing regimens are especially challenging in the developing world where limited healthcare access poses a major logistical barrier to immunization. Over the past four decades, researchers have attempted to overcome this issue by developing single-administration vaccines based on controlled-release antigen delivery systems. These systems can be administered once, but release antigen over an extended period of time to elicit both primary and secondary immune responses resulting in antigen-specific immunological memory. Unfortunately, unlike controlled release systems for drugs, single-administration vaccines have yet to be commercialized due to poor antigen stability and difficulty in obtaining unconventional release kinetics. This review discusses the current state of single-administration vaccination, challenges delaying the development of these vaccines, and potential strategies for overcoming these challenges.
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Affiliation(s)
- Kevin J McHugh
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Rohiverth Guarecuco
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Robert Langer
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Ana Jaklenec
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, United States.
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11
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White AFB, Demchenko AV. Modulating LPS signal transduction at the LPS receptor complex with synthetic Lipid A analogues. Adv Carbohydr Chem Biochem 2015; 71:339-89. [PMID: 25480508 DOI: 10.1016/b978-0-12-800128-8.00005-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Sepsis, defined as a clinical syndrome brought about by an amplified and dysregulated inflammatory response to infections, is one of the leading causes of death worldwide. Despite persistent attempts to develop treatment strategies to manage sepsis in the clinical setting, the basic elements of treatment have not changed since the 1960s. As such, the development of effective therapies for reducing inflammatory reactions and end-organ dysfunction in critically ill patients with sepsis remains a global priority. Advances in understanding of the immune response to sepsis provide the opportunity to develop more effective pharmaceuticals. This article details current information on the modulation of the lipopolysaccharide (LPS) receptor complex with synthetic Lipid A mimetics. As the initial and most critical event in sepsis pathophysiology, the LPS receptor provides an attractive target for antisepsis agents. One of the well-studied approaches to sepsis therapy involves the use of derivatives of Lipid A, the membrane-anchor portion of an LPS, which is largely responsible for its endotoxic activity. This article describes the structural and conformational requirements influencing the ability of Lipid A analogues to compete with LPS for binding to the LPS receptor complex and to inhibit the induction of the signal transduction pathway by impairing LPS-initiated receptor dimerization.
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Affiliation(s)
- Aileen F B White
- Dextra Laboratories Ltd., Science and Technology Centre, Earley Gate, Reading, United Kingdom.
| | - Alexei V Demchenko
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri, USA.
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12
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Zariri A, van der Ley P. Biosynthetically engineered lipopolysaccharide as vaccine adjuvant. Expert Rev Vaccines 2015; 14:861-76. [PMID: 25797360 DOI: 10.1586/14760584.2015.1026808] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Lipopolysaccharide (LPS), a dominant component of the Gram-negative bacterial outer membrane, is a strong activator of the innate immune system, and thereby an important determinant in the adaptive immune response following bacterial infection. This adjuvant activity can be harnessed following immunization with bacteria-derived vaccines that naturally contain LPS, and when LPS or molecules derived from it are added to purified vaccine antigens. However, the downside of the strong biological activity of LPS is its ability to contribute to vaccine reactogenicity. Modification of the LPS structure allows triggering of a proper immune response needed in a vaccine against a particular pathogen while at the same time lowering its toxicity. Extensive modifications to the basic structure are possible by using our current knowledge of bacterial genes involved in LPS biosynthesis and modification. This review focuses on biosynthetic engineering of the structure of LPS and implications of these modifications for generation of safe adjuvants.
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Affiliation(s)
- Afshin Zariri
- Institute for Translational Vaccinology (InTraVacc), Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
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13
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Scior T, Alexander C, Zaehringer U. Reviewing and identifying amino acids of human, murine, canine and equine TLR4 / MD-2 receptor complexes conferring endotoxic innate immunity activation by LPS/lipid A, or antagonistic effects by Eritoran, in contrast to species-dependent modulation by lipid IVa. Comput Struct Biotechnol J 2013; 5:e201302012. [PMID: 24688705 PMCID: PMC3962135 DOI: 10.5936/csbj.201302012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 02/12/2013] [Accepted: 02/17/2013] [Indexed: 11/28/2022] Open
Abstract
There is literature evidence gathered throughout the last two decades reflecting unexpected species differences concerning the immune response to lipid IVa which provides the opportunity to gain more detailed insight by the molecular modeling approach described in this study. Lipid IVa is a tetra-acylated precursor of lipid A in the biosynthesis of lipopolysaccharide (LPS) in Gram-negative bacteria. Lipid A of the prototypic E. coli-type is a hexa-acylated structure that acts as an agonist in all tested mammalian species by innate immunorecognition via the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD-2) receptor complex. In contrast, lipid IVa is proinflammatory in mouse cells (agonism) but it remains inactive to human macrophages and even antagonizes the action of potent agonists like E. coli-type lipid A. This particular ambivalent activity profile of lipid IVa has been confirmed in other mammalian species: in equine cells Lipid IVa also acts in a weak agonistic manner, whereas being inactive and antagonizing the lipid A-induced activation of canine TLR4/MD-2. Intriguingly, the respective TLR4 amino acid sequences of the latter species are more identical to the human (67%, 68%) than to the murine (62%, 58%) ortholog. In order to address the unpaired activity-sequence dualism for human, murine, canine and equine species regarding the activity of lipid IVa as compared to LPS and lipid A and, we review the literature and computationally pinpoint the differential biological effects of lipid IVa versus LPS and lipid A to specific amino acid residues. In contrast to lipid IVa the structurally related synthetic compound Eritoran (E5564) acts consistently in an antagonistic manner in these mammalian species and serves as a reference ligand for molecular modeling in this study. The combined evaluation of data sets provided by prior studies and in silico homology mapping of differential residues of TLR4/MD-2 complexes lends detailed insight into the driving forces of the characteristic binding modes of the lipid A domain in LPS and the precursor structure lipid IVa to the receptor complex in individual mammalian species.
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Affiliation(s)
- Thomas Scior
- Departamento de Farmacia, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue., Mexico
| | - Christian Alexander
- Division of Immunochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
| | - Ulrich Zaehringer
- Division of Immunochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
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14
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Bowen WS, Gandhapudi SK, Kolb JP, Mitchell TC. Immunopharmacology of Lipid A Mimetics. ADVANCES IN PHARMACOLOGY 2013; 66:81-128. [DOI: 10.1016/b978-0-12-404717-4.00003-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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15
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Alving CR, Rao M, Steers NJ, Matyas GR, Mayorov AV. Liposomes containing lipid A: an effective, safe, generic adjuvant system for synthetic vaccines. Expert Rev Vaccines 2012; 11:733-44. [PMID: 22873129 DOI: 10.1586/erv.12.35] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Liposomes containing monophosphoryl lipid A (MPLA) have previously exhibited considerable potency and safety in human trials with a variety of candidate vaccines, including vaccines to malaria, HIV-1 and several different types of cancer. The long history of research and development of MPLA and liposomal MPLA as vaccine adjuvants reveals that there are numerous opportunities for creation and development of generic (nonproprietary) adjuvant system formulations with these materials that are not only highly potent and safe, but also readily available as native materials or as synthetic compounds. They are easily manufactured as potentially inexpensive and easy to use adjuvant systems and might be effective even with synthetic peptides as antigens.
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Affiliation(s)
- Carl R Alving
- Laboratory of Adjuvant and Antigen Research, US Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
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16
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Structural basis of species-specific endotoxin sensing by innate immune receptor TLR4/MD-2. Proc Natl Acad Sci U S A 2012; 109:7421-6. [PMID: 22532668 DOI: 10.1073/pnas.1201193109] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lipopolysaccharide (LPS), also known as endotoxin, activates the innate immune response through toll-like receptor 4 (TLR4) and its coreceptor, MD-2. MD-2 has a unique hydrophobic cavity that directly binds to lipid A, the active center of LPS. Tetraacylated lipid IVa, a synthetic lipid A precursor, acts as a weak agonist to mouse TLR4/MD-2, but as an antagonist to human TLR4/MD-2. However, it remains unclear as to how LPS and lipid IVa show agonistic or antagonistic activities in a species-specific manner. The present study reports the crystal structures of mouse TLR4/MD-2/LPS and TLR4/MD-2/lipid IVa complexes at 2.5 and 2.7 Å resolutions, respectively. Mouse TLR4/MD-2/LPS exhibited an agonistic "m"-shaped 2:2:2 complex similar to the human TLR4/MD-2/LPS complex. Mouse TLR4/MD-2/lipid IVa complex also showed an agonistic structural feature, exhibiting architecture similar to the 2:2:2 complex. Remarkably, lipid IVa in the mouse TLR4/MD-2 complex occupied nearly the same space as LPS, although lipid IVa lacked the two acyl chains. Human MD-2 binds lipid IVa in an antagonistic manner completely differently from the way mouse MD-2 does. Together, the results provide structural evidence of the agonistic property of lipid IVa on mouse TLR4/MD-2 and deepen understanding of the ligand binding and dimerization mechanism by the structurally diverse LPS variants.
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17
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Brogden NK, Brogden KA. Will new generations of modified antimicrobial peptides improve their potential as pharmaceuticals? Int J Antimicrob Agents 2011; 38:217-25. [PMID: 21733662 DOI: 10.1016/j.ijantimicag.2011.05.004] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 05/09/2011] [Indexed: 12/20/2022]
Abstract
The concept of antimicrobial peptides (AMPs) as potent pharmaceuticals is firmly established in the literature, and most research articles on this topic conclude by stating that AMPs represent promising therapeutic agents against bacterial and fungal pathogens. Indeed, early research in this field showed that AMPs were diverse in nature, had high activities with low minimal inhibitory concentrations, had broad spectrums of activity against bacterial, fungal and viral pathogens, and could easily be manipulated to alter their specificities, reduce their cytotoxicities and increase their antimicrobial activities. Unfortunately, commercial development of these peptides, for even the simplest of applications, has been very limited. With some peptides there are obstacles with their manufacture, in vivo efficacy and in vivo retention. More recently, the focus has shifted. Contemporary research now uses a more sophisticated approach to develop AMPs that surmount many of these prior obstacles. AMP mimetics, hybrid AMPs, AMP congeners, cyclotides and stabilised AMPs, AMP conjugates and immobilised AMPs have all emerged with selective or 'targeted' antimicrobial activities, improved retention, or unique abilities that allow them to bind to medical or industrial surfaces. These groups of new peptides have creative medical and industrial application potentials to treat antibiotic-resistant bacterial infections and septic shock, to preserve food or to sanitise surfaces both in vitro and in vivo.
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Affiliation(s)
- Nicole K Brogden
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
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19
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Coincorporation of LpxL1 and PagL mutant lipopolysaccharides into liposomes with Neisseria meningitidis opacity protein: influence on endotoxic and adjuvant activity. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:487-95. [PMID: 20107001 DOI: 10.1128/cvi.00423-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Wild-type lipopolysaccharide (LPS) of Neisseria meningitidis normally contains six acyl chains. Penta-acylated LPS forms were generated through inactivation of the lpxL1 gene or through the expression of the Bordetella bronchiseptica pagL gene in N. meningitidis. The resulting LPS species, designated LpxL1 LPS and PagL LPS, respectively, display reduced endotoxic activity compared to wild-type LPS. Here, we determined the adjuvant potential of PagL LPS by comparison with the broadly used LpxL1 LPS. We also investigated the potential benefit for adjuvanticity of coincorporating these LPS species, together with the meningococcal opacity-associated protein OpaJ as a model antigen, in a liposomal delivery system. PagL LPS showed a higher endotoxic activity than LpxL1 LPS, and their incorporation into liposomes significantly reduced their endotoxic activity as determined by measuring the induction of interleukin-6 (IL-6) production in a murine macrophage cell line. To determine the adjuvant effect, BALB/c mice were immunized with OpaJ-containing liposomes and either free LPS or LPS coincorporated into the proteoliposomes. OpaJ-containing liposomes adjuvanted with AlPO(4) or not adjuvanted at all were included as control groups. In the appropriate dose, PagL LPS showed a superior adjuvant effect compared with LpxL1 LPS, and for both LPS types, free LPS showed a higher adjuvant effect than when coincorporated into the liposomes, as evidenced by higher titers of IgG2a and IgG2b antibodies against OpaJ(+) meningococci and higher bactericidal titers. In conclusion, PagL LPS is a better adjuvant than LpxL1 LPS, but coincorporation of either LPS into proteoliposomes did not improve their adjuvant activity.
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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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Meng J, Lien E, Golenbock DT. MD-2-mediated ionic interactions between lipid A and TLR4 are essential for receptor activation. J Biol Chem 2009; 285:8695-702. [PMID: 20018893 DOI: 10.1074/jbc.m109.075127] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Lipopolysaccharide (LPS) activates innate immune responses through TLR4.MD-2. LPS binds to the MD-2 hydrophobic pocket and bridges the dimerization of two TLR4.MD-2 complexes to activate intracellular signaling. However, exactly how lipid A, the endotoxic moiety of LPS, activates myeloid lineage cells remains unknown. Lipid IV(A), a tetra-acylated lipid A precursor, has been used widely as a model for lipid A activation. For unknown reasons, lipid IV(A) activates proinflammatory responses in rodent cells but inhibits the activity of LPS in human cells. Using stable TLR4-expressing cell lines and purified monomeric MD-2, as well as MD-2-deficient bone marrow-derived macrophages, we found that both mouse TLR4 and mouse MD-2 are required for lipid IV(A) activation. Computational studies suggested that unique ionic interactions exist between lipid IV(A) and TLR4 at the dimerization interface in the mouse complex only. The negatively charged 4'-phosphate on lipid IV(A) interacts with two positively charged residues on the opposing mouse, but not human, TLR4 (Lys(367) and Arg(434)) at the dimerization interface. When replaced with their negatively charged human counterparts Glu(369) and Gln(436), mouse TLR4 was no longer responsive to lipid IV(A). In contrast, human TLR4 gained lipid IV(A) responsiveness when ionic interactions were enabled by charge reversal at the dimerization interface, defining the basis of lipid IV(A) species specificity. Thus, using lipid IV(A) as a selective lipid A agonist, we successfully decoupled and coupled two sequential events required for intracellular signaling: receptor engagement and dimerization, underscoring the functional role of ionic interactions in receptor activation.
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Affiliation(s)
- Jianmin Meng
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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Geurtsen J, Dzieciatkowska M, Steeghs L, Hamstra HJ, Boleij J, Broen K, Akkerman G, El Hassan H, Li J, Richards JC, Tommassen J, van der Ley P. Identification of a novel lipopolysaccharide core biosynthesis gene cluster in Bordetella pertussis, and influence of core structure and lipid A glucosamine substitution on endotoxic activity. Infect Immun 2009; 77:2602-11. [PMID: 19364841 PMCID: PMC2708539 DOI: 10.1128/iai.00033-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 02/22/2009] [Accepted: 04/03/2009] [Indexed: 01/10/2023] Open
Abstract
Lipopolysaccharide (LPS), also known as endotoxin, is one of the main constituents of the gram-negative bacterial outer membrane. Whereas the lipid A portion of LPS is generally considered the main determinant for endotoxic activity, the oligosaccharide moiety plays an important role in immune evasion and the interaction with professional antigen-presenting cells. Here we describe a novel four-gene cluster involved in the biosynthesis of the Bordetella pertussis core oligosaccharide. By insertionally inactivating these genes and studying the resulting LPS structures, we show that at least two of the genes encode active glycosyltransferases, while a third gene encodes a deacetylase also required for biosynthesis of full-length oligosaccharide. In addition, we demonstrate that mutations in the locus differentially affect LPS and whole-cell endotoxic activities. Furthermore, while analyzing the mutant LPS structures, we confirmed a novel modification of the lipid A phosphate with glucosamine and found that inactivation of the responsible glycosyltransferase reduces the endotoxic activity of the LPS.
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Affiliation(s)
- Jeroen Geurtsen
- Department of Molecular Microbiology, Utrecht University, 3584 CH Utrecht, The Netherlands
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Gutsmann T, Howe J, Zähringer U, Garidel P, Schromm A, Koch M, Fujimoto Y, Fukase K, Moriyon I, Martínez-de-Tejada G, Brandenburg K. Structural prerequisites for endotoxic activity in the Limulus test as compared to cytokine production in mononuclear cells. Innate Immun 2009; 16:39-47. [DOI: 10.1177/1753425909106447] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The structural prerequisites for lipopolysaccharide (LPS) and its partial structures for the activation of the Limulus clotting cascade (Limulus amebocyte lysate [LAL] test) are described and compared with the corresponding requirements for the activation of human immune cells such as mononuclear cells. A necessary, but not sufficient, structural motif for this is the presence of the 4′-phosphate-diglucosamine backbone recognition structure (‘epitope’) in lipid A. High activity is only expressed by assemblies of endotoxins, but this is largely independent of the type of supramolecular aggregate structure. A particular conformation of the epitope within the lipid A assembly must be present, which is influenced by addition of further saccharide units to the lipid A moiety, but also reacts slightly to the acylation pattern. In contrast, the cytokine production of human immune cells induced by LPS sensitively depends on the type of its aggregate structure. In the case of a hexa-acylated bisphosphorylated lipid A structure, high activity is only observed with cubic inverted aggregates. Furthermore, addition of antimicrobial agents (such as polymyxin B) leads to a nearly complete inhibition of cytokine production, whereas the reduction in the Limulus assay is much lower. These data are important since a reliable determination of endotoxin concentrations, in particular with respect to its ability to elicit severe infections, is of high interest.
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Affiliation(s)
| | - J. Howe
- Forschungszentrum Borstel, Borstel, Germany
| | | | - P. Garidel
- Universität Halle-Wittenberg, Institut für Physikalische Chemie, Halle, Germany
| | | | - M.H.J. Koch
- European Molecular Biology Laboratory, Hamburg Outstation c/o DESY, Hamburg, Germany
| | - Y. Fujimoto
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - K. Fukase
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan
| | - I. Moriyon
- Department of Microbiology, Universidad de Navarra, Pamplona, Spain
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Kitazawa T, Tsujimoto T, Kawaratani H, Fukui H. Therapeutic approach to regulate innate immune response by Toll-like receptor 4 antagonist E5564 in rats with D-galactosamine-induced acute severe liver injury. J Gastroenterol Hepatol 2009; 24:1089-94. [PMID: 19226379 DOI: 10.1111/j.1440-1746.2008.05770.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Toll-like receptor 4 (TLR4) is a transmembrane protein, existing mainly in macrophages, such as Kupffer cells of the liver. It plays an important role in recognizing and mediating macrophage activation and pro-inflammatory cytokine release. Activation of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-alpha is pivotal in the progression of liver injury. Gut-derived endotoxin has been considered to play an important role in the development and progression of a D-galactosamine (GalN)-induced acute severe liver injury (ALI) model. E5564, a synthetic analog of the lipid A component of endotoxin, inhibits endotoxin-stimulated inflammation and is under study for patients with sepsis. In this study, we seek to explore the effect of TLR4 antagonist E5564 on GalN-induced ALI in rats. METHODS ALI was induced in male Wistar rats by the i.p. injection of 1 g/kg bodyweight of GalN and immediately after GalN injection they were treated with an i.v. injection of 3 mg/kg bodyweight of E5564. At 24 h after GalN injection with or without E5564, serum levels of total bilirubin (T.Bil), alanine aminotransferase (ALT) and TNF-alpha were analyzed. Expression levels of TNF-alpha, TLR4 and CD14 mRNA in the whole liver of rats was detected by reverse transcription polymerase chain reaction analysis. RESULTS The i.v. injection of E5564 reduced the elevation of serum T.Bil, ALT and TNF-alpha levels in rats treated with GalN. The expression level of TNF-alpha mRNA in the whole liver, which was increased at 24 h after GalN injection, was also reduced by i.v. injection of E5564. CONCLUSION TLR4 antagonist E5564 reduced GalN-induced ALI in rats. It may contribute to the treatment of acute liver failure through blocking endotoxin-induced TNF-alpha overproduction of macrophages.
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Affiliation(s)
- Toshiyuki Kitazawa
- Third Department of Internal Medicine, Nara Medical University, Kashihara, Nara, Japan
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Brandenburg K, Seydel U. Conformation and Supramolecular Structure of Lipid A. LIPID A IN CANCER THERAPY 2009; 667:25-38. [DOI: 10.1007/978-1-4419-1603-7_3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Differential activation of human and mouse Toll-like receptor 4 by the adjuvant candidate LpxL1 of Neisseria meningitidis. Infect Immun 2008; 76:3801-7. [PMID: 18490457 DOI: 10.1128/iai.00005-08] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisseria meningitidis LpxL1 lipopolysaccharide (LPS) bearing penta-acylated lipid A is considered a promising adjuvant candidate for inclusion in future N. meningitidis vaccines, as it elicits a markedly reduced endotoxic response in human macrophages relative to that in wild-type (hexa-acylated) LPS, while it is an equally effective adjuvant in mice. As dendritic cells (DC) and Toll-like receptors (TLR) are regarded as central mediators in the initiation of an immune response, here we evaluated the ability of LpxL1 LPS to mature and to activate human DC and examined its TLR4-/MD-2-activating properties. Unexpectedly, purified LpxL1 LPS displayed minimal human DC-stimulating properties compared to wild-type LPS. Although whole bacteria induced DC maturation and activation irrespective of their type of LPS, the LpxL1 mutant failed to activate the human recombinant TLR4/MD-2 complex expressed in HeLa cells. Similarly, purified LpxL1 LPS was unable to activate human TLR4/MD-2 and it even acted as an antagonist of wild-type LPS. Both wild-type and LpxL1 LPSs activated the murine TLR4/MD-2 complex, consistent with their abilities to induce maturation and activation of murine DC. Assays with cells transfected with different combinations of human and murine TLR4 and MD-2 indicated that TLR4 was a more-major determinant of the LPS response than MD-2. The species-specific activation of the TLR4/MD-2 complex by LpxL1 LPS may have an impact on the use of LpxL1 LPS as an adjuvant and the use of murine immunization models in human meningococcal vaccine development.
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Faunce CA, Paradies HH. Observations of liquidlike order of charged rodlike lipid A diphosphate assemblies at pH 8.5. J Chem Phys 2008; 128:065105. [DOI: 10.1063/1.2834206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Asai Y, Makimura Y, Kawabata A, Ogawa T. Soluble CD14 discriminates slight structural differences between lipid as that lead to distinct host cell activation. THE JOURNAL OF IMMUNOLOGY 2008; 179:7674-83. [PMID: 18025213 DOI: 10.4049/jimmunol.179.11.7674] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Soluble CD14 (sCD14) in serum is known to sensitize host cells to LPS. In the present study, the contributions of sCD14 and LPS-binding protein to a lipid A moiety from LPS preparations of periodontopathogenic Fusobacterium nucleatum sp. nucleatum were compared with that of Escherichia coli-type synthetic lipid A (compound 506). F. nucleatum lipid A was identified to be a hexa-acylated fatty acid composed of tetradecanoate (C(14)) and hexadecanoate (C(16)), similar to dodecanoate (C(12)) and C(14) in compound 506. The two lipid A specimens exhibited nearly the same reactivity in Limulus amoebocyte lysate assays, though F. nucleatum lipid A showed a weaker lethal toxicity. Both lipid A specimens showed nearly the same activities toward host cells in the absence of FBS, though compound 506 exhibited much stronger activity in the presence of FBS, sCD14, or sCD14 together with LPS-binding protein. Furthermore, native PAGE/Western immunoblot assays demonstrated that F. nucleatum lipid A had a weaker binding to sCD14 as compared with compound 506. These results suggest that sCD14 is able to discriminate the slight structural differences between these lipid As, which causes their distinct host cell activation activities.
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Affiliation(s)
- Yasuyuki Asai
- Department of Oral Microbiology, Asahi University School of Dentistry, Gifu, Japan
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Lipid A and liposomes containing lipid A as antigens and adjuvants. Vaccine 2007; 26:3036-45. [PMID: 18226433 DOI: 10.1016/j.vaccine.2007.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 11/30/2007] [Accepted: 12/01/2007] [Indexed: 11/23/2022]
Abstract
Lipid A derived from Gram-negative bacterial lipopolysaccharide is a potent adjuvant and antigen. Incorporation of lipid A into liposomes renders the liposomes themselves immunogenic, resulting in generation of specific antibodies that recognize either the individual liposomal lipids, or the unique pattern presented by the combination of lipids. Using liposomes containing lipid A, numerous polyclonal antisera and monoclonal antibodies have been produced against phospholipids, cholesterol, glycosphingolipids, and lipid A. Many of these antibodies have binding characteristics that are apparently similar to natural antibodies that are normally present in all human sera, and also antibodies that arise in response to various infections. Such antibodies probably represent a bridge between innate and adaptive immunity. The possible utility of liposomes containing lipid A as a constituent of certain types of novel vaccines was suggested by the observation that murine monoclonal antibodies to liposomal phosphatidylinositol-4-phosphate neutralized primary isolates of two different clades of HIV-1 in a human peripheral blood mononuclear cell neutralization assay.
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Geurtsen J, Angevaare E, Janssen M, Hamstra HJ, ten Hove J, de Haan A, Kuipers B, Tommassen J, van der Ley P. A novel secondary acyl chain in the lipopolysaccharide of Bordetella pertussis required for efficient infection of human macrophages. J Biol Chem 2007; 282:37875-84. [PMID: 17967899 DOI: 10.1074/jbc.m706391200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lipopolysaccharide is one of the major constituents of the Gram-negative bacterial outer membrane and is a potent stimulator of the host innate immune response. The biosynthesis of the lipid A moiety of lipopolysaccharide is a complex process in which multiple gene products are involved. Two late lipid A acyl transferases, LpxL and LpxM, were first identified in Escherichia coli and shown to be responsible for the addition of secondary acyl chains to the 2' and 3' positions of lipid A, respectively. Here, we describe the identification of two lpxL homologues in the genome of Bordetella pertussis. We show that one of them, LpxL2, is responsible for the addition of the secondary myristate group that is normally present at the 2' position of B. pertussis lipid A, whereas the other one, LpxL1, mediates the addition of a previously unrecognized secondary 2-hydroxy laurate at the 2 position. Increased expression of lpxL1 results in the appearance of a hexa-acylated lipopolysaccharide form with strongly increased endotoxic activity. In addition, we show that an lpxL1-deficient mutant of B. pertussis displays a defect in the infection of human macrophages.
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Affiliation(s)
- Jeroen Geurtsen
- Department of Molecular Microbiology, Utrecht University, Padualaan 8, Utrecht, The Netherlands
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Faunce CA, Reichelt H, Quitschau P, Paradies HH. Ordering of lipid A-monophosphate clusters in aqueous solutions. J Chem Phys 2007; 127:115103. [PMID: 17887884 DOI: 10.1063/1.2768524] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this investigation, a study of the self-assembly of electrostatically stabilized aqueous dispersions of nanometric lipid A-monophosphate clusters from Escherichia coli was carried out in three different volume-fraction regimes. The experimental techniques used in the investigation were osmotic pressure, static and quasielastic light scattering, scanning electron microscopy and transmission electron microscopy, and small-angle x-ray scattering. Experiments were carried out at low ionic strength (I=0.1-5.0 mM NaCl) at 25 degrees C. At volume fractions between 1.5x10(-4)<or=phi<or=5.4x10(-4), the lipid A-monophosphate clusters had an average rms hydrodynamic diameter of d=7.5 nm, and a weighted-average molecular weight of (1.78+/-0.23)x10(5) g mol(-1). Quasielastic light scattering (LS) experiments yield similar values for the particle size and particle size distribution compared to electron microscopy, small-angle x-ray scattering, and LS experiments. When the volume fraction was increased to a higher regime 5.4x10(-4)<or=phi<or=9.50x10(-4), much larger clusters of lipid A monophosphate formed. The clusters detected in this volume-fraction range were assembled from between 8 and 52 of the d=7.5 nm clusters and the assemblies are densely packed in such a way that colloidal crystals composed of the monodisperse microspheres are in physical contact with their nearest neighbors. Clusters that formed in volume fractions between 10.0x10(-4)<or=phi<or=40.0x10(-4) revealed a weighted-average molecular weight of (10.15+/-0.17)x10(6) g mol(-1) and a hydrodynamic diameter of approximately d=70.6 nm. The crossover volume fraction between the small and the large clusters appeared at phicr=5.05x10(-4). In the intermediate volume-fraction range, the scattered intensity I(Q) vs Q curves (light and x rays) showed asymptotic behavior. From the asymptotic curves, the scattered intensity, the relationship between the average mass and radius, and the fractal dimension df were determined. The df value, which was evaluated from the expression I(Q) proportional, RGdf, was found to be 1.67+/-0.03, a value that was virtually independent of the ionic strength (0.1-5.0 mM NaCl) at 25 degrees C. Even at a very low ionic strength (I=0.10 mM NaCl), lipid A monophosphate formed a number of differently shaped clusters. Electron microscope images showed that two types of self-assembled clusters existed at the lowest volume-fraction range studied and also dominated the images taken at the higher volume-fraction regimes. One type of cluster showed a cubic morphology and a size variation of 50-100 nm, while another type took on the appearance of a quadratic cylinder, with dimensions of 50x150 nm2. The other clusters appeared in various shapes: dimers, trimers, and distorted tetramers, which were quite different from the ones previously observed for lipid A diphosphate. Small-angle x-ray diffraction experiments on lipid A-monophosphate clusters suspended in water, containing 5 mM NaCl (25 degrees C), indicated the existence of long-range order of d=7.5 nm. At low polydispersity, two distinct types of lipid A-monophosphate colloidal clusters were able to form at low polydispersity and were subsequently identified using light scattering, small-angle x-ray scattering, and selected-area electron diffraction. From an analysis of experimental results obtained from these clusters, distinct peaks could be assigned to a body-centered cubic (bcc) lattice, with a=49.5+/-1.8 nm. The solution structure found for lipid A diphosphate at volume fractions of 3.75x10(-4)<or=phi<or=4.15x10(-4) also exhibited a (bcc)-type lattice; however, a=36.1 nm [C. A. Faunceet al. J. Phys. Chem. 107, 2214 (2003)]. Using the particle and cluster properties determined from small-angle x-ray scattering, light scattering, and osmotic-pressure measurements as a function of volume fraction, good agreement was found between the directly measured osmotic-pressure values and those calculated from scattering experiments.
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Affiliation(s)
- Chester A Faunce
- Institute for Materials Research, Joule Physics Laboratory, The University of Salford, Salford M5 4WT, United Kingdom
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Coats SR, Do CT, Karimi-Naser LM, Braham PH, Darveau RP. Antagonistic lipopolysaccharides block E. coli lipopolysaccharide function at human TLR4 via interaction with the human MD-2 lipopolysaccharide binding site. Cell Microbiol 2007; 9:1191-202. [PMID: 17217428 DOI: 10.1111/j.1462-5822.2006.00859.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Lipopolysaccharides containing underacylated lipid A structures exhibit reduced abilities to activate the human (h) Toll-like receptor 4 (TLR4) signalling pathway and function as potent antagonists against lipopolysaccharides bearing canonical lipid A structures. Expression of underacylated lipopolysaccharides has emerged as a novel mechanism utilized by microbial pathogens to modulate host innate immune responses. Notably, antagonistic lipopolysaccharides are prime therapeutic candidates for combating Gram negative bacterial sepsis. Penta-acylated msbB and tetra-acylated Porphyromonas gingivalis lipopolysaccharides functionally antagonize hexa-acylated Escherichia coli lipopolysaccharide-dependent activation of hTLR4 through the coreceptor, hMD-2. Here, the molecular mechanism by which these antagonistic lipopolysaccharides act at hMD-2 is examined. We present evidence that both msbB and P. gingivalis lipopolysaccharides are capable of direct binding to hMD-2. These antagonistic lipopolysaccharides can utilize at least two distinct mechanisms to block E. coli lipopolysaccharide-dependent activation of hTLR4. The main mechanism consists of direct competition between the antagonistic lipopolysaccharides and E. coli lipopolysaccharide for the same binding site on hMD-2, while the secondary mechanism involves the ability of antagonistic lipopolysaccharide-hMD-2 complexes to inhibit E. coli lipopolysaccharide-hMD-2 complexes function at hTLR4. It is also shown that both hTLR4 and hMD-2 contribute to the species-specific recognition of msbB and P. gingivalis lipopolysaccharides as antagonists at the hTLR4 complex.
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Affiliation(s)
- Stephen R Coats
- Department of Periodontics, University of Washington School of Dentistry, Seattle, WA 98195, USA.
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Brett PJ, Burtnick MN, Snyder DS, Shannon JG, Azadi P, Gherardini FC. Burkholderia mallei expresses a unique lipopolysaccharide mixture that is a potent activator of human Toll-like receptor 4 complexes. Mol Microbiol 2006; 63:379-90. [PMID: 17163980 PMCID: PMC1974782 DOI: 10.1111/j.1365-2958.2006.05519.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Burkholderia mallei, the aetiologic agent of glanders, causes a variety of illnesses in animals and humans ranging from occult infections to acute fulminating septicaemias. To better understand the role of lipopolysaccharide (LPS) in the pathogenesis of these diseases, studies were initiated to characterize the structural and biological properties of lipid A moieties expressed by this organism. Using a combination of chemical analyses and MALDI-TOF mass spectrometry, B. mallei was shown to express a heterogeneous mixture of tetra- and penta-acylated lipid A species that were non-stoichiometrically substituted with 4-amino-4-deoxy-arabinose residues. The major penta-acylated species consisted of bisphosphorylated d-glucosamine disaccharide backbones possessing two amide linked 3-hydroxyhexadecanoic acids, two ester linked 3-hydroxytetradecanoic acids [C14:0(3-OH)] and an acyloxyacyl linked tetradecanoic acid, whereas, the major tetra-acylated species possessed all but the 3'-linked C14:0(3-OH) residues. In addition, although devoid of hexa-acylated species, B. mallei LPS was shown to be a potent activator of human Toll-like receptor 4 complexes and stimulated human macrophage-like cells (THP-1 and U-937), monocyte-derived macrophages and dendritic cells to produce high levels of TNF-alpha, IL-6 and RANTES. Based upon these results, it appears that B. mallei LPS is likely to play a significant role in the pathogenesis of human disease.
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Affiliation(s)
- Paul J Brett
- Laboratory of Zoonotic Pathogens, Rocky Mountain LaboratoriesNIAID, NIH, Hamilton, MT 59840, USA.
| | - Mary N Burtnick
- Laboratory of Zoonotic Pathogens, Rocky Mountain LaboratoriesNIAID, NIH, Hamilton, MT 59840, USA.
| | - D Scott Snyder
- Complex Carbohydrate Research Center, The University of GeorgiaAthens, GA 30602, USA.
| | - Jeffrey G Shannon
- Laboratory of Intracellular Parasites, Rocky Mountain LaboratoriesNIAID, NIH, Hamilton, MT 59840, USA.
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, The University of GeorgiaAthens, GA 30602, USA.
| | - Frank C Gherardini
- Laboratory of Zoonotic Pathogens, Rocky Mountain LaboratoriesNIAID, NIH, Hamilton, MT 59840, USA.
- For correspondence. E-mail ; Tel. (+1) 406 363 9474; Fax (+1) 406 363 9478
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Kato N, Nakayama Y, Nakajima Y, Samoto H, Saito R, Yamanouchi F, Masunaga H, Shimizu E, Ogata Y. Regulation of bone sialoprotein (BSP) gene transcription by lipopolysaccharide. J Cell Biochem 2006; 97:368-79. [PMID: 16187297 DOI: 10.1002/jcb.20628] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lipopolysaccharide (LPS) is a major mediator of inflammatory responses in periodontal disease that inhibits bone formation and stimulates bone resorption. To determine the molecular mechanisms involved in the suppression of bone formation, we have analyzed the effects of LPS on BSP gene expression. Bone sialoprotein (BSP) is a mineralized tissue-specific protein that appears to function in the initial mineralization of bone. Treatment of osteoblast-like ROS 17/2.8 cells with LPS (1 microg/ml) for 12 h caused a marked reduction in BSP mRNA levels. The addition of antioxidant N-acetylcysteine (NAC; 20 mM) 30 min prior to stimulation with LPS attenuated the inhibition of BSP mRNA levels. Transient transfection analyses, using chimeric constructs of the rat BSP gene promoter linked to a luciferase reporter gene, revealed that LPS (1 microg/ml) suppressed expression of luciferase construct, encompassing BSP promoter nucleotides -108 to +60, transfected into ROS17/2.8 cells. The effects of LPS were inhibited by protein kinase A (PKA) inhibitor, H89 and the tyrosine kinase inhibitor, herbimycin A (HA). Introduction of 2 bp mutations in the inverted CCAAT box (ATTGG; nts -50 and -46), a cAMP response element (CRE; nts -75 to -68), a FGF response element (FRE; nts -92 to -85), and a pituitary specific transcription factor binding element (Pit-1; nts -111 to -105) showed that the LPS effects were mediated by the CRE and FRE. Whereas the FRE and 3'-FRE DNA-protein complexes were decreased by LPS, CRE DNA-protein complex did not change after LPS treatment. These studies, therefore, show that LPS suppresses BSP gene transcription through PKA and tyrosine kinase-dependent pathways and that the LPS effects are mediated through CRE and FRE elements in the proximal BSP gene promoter.
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Affiliation(s)
- Naoko Kato
- Department of Periodontology, Nihon University School of Dentistry at Matsudo, Chiba, 271-8587, Japan
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Yu L, Tan M, Ho B, Ding JL, Wohland T. Determination of critical micelle concentrations and aggregation numbers by fluorescence correlation spectroscopy: Aggregation of a lipopolysaccharide. Anal Chim Acta 2006; 556:216-25. [PMID: 17723352 DOI: 10.1016/j.aca.2005.09.008] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Revised: 08/25/2005] [Accepted: 09/06/2005] [Indexed: 11/29/2022]
Abstract
Fluorescence correlation spectroscopy (FCS) is often used to determine the mass or radius of a particle by using the dependence of the diffusion coefficient on the mass and shape. In this article we discuss how the particle size of aggregates can be measured by using the concentration dependence of the amplitude of the autocorrelation function (ACF) instead of the temporal decay. We titrate a solution of aggregates or micelles with a fluorescent label that possesses a high affinity for these structures and measure the changes in the amplitude of the ACF. We develop the theory describing the change of the ACF amplitude with increasing concentrations of labels and use it to fit experimental data. It is shown how this method can determine the aggregation number and critical micelle concentration of a standard detergent nonaethylene glycol monododecyl ether (C12E9) and a lipopolysaccharide (LPS: Escherichia coli 0111:B4).
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Affiliation(s)
- Lanlan Yu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
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Dixon DR, Darveau RP. Lipopolysaccharide heterogeneity: innate host responses to bacterial modification of lipid a structure. J Dent Res 2005; 84:584-95. [PMID: 15972584 DOI: 10.1177/154405910508400702] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The innate host response system is composed of various mechanisms designed to detect and facilitate host responses to microbial components, such as lipopolysaccharides (LPS). To enable this to occur, innate systems contain multiple pattern recognition receptors (i.e., LBP, CD14, and TLRs), which identify certain features within bacterial LPS that are foreign to the host, as well as essential and uniquely specific for bacteria. Innate host identification of unique bacterial components or patterns, therefore, relies on the inability of bacteria to alter these essential or critical components dramatically. Historically, LPS have been viewed as essential outer-membrane molecules containing both a highly variable outer region (O-segment) as well as a relatively conserved inner region (lipid A). However, over the last decade, new evidence has emerged, revealing that increased natural diversity or heterogeneity within specific components of LPS, such as lipid A-resulting in minor to moderate changes in lipid A structure-can produce dramatic host responses. Therefore, examples of natural lipid A heterogeneity, and the mechanisms that control it, represent a novel approach in which bacteria modulate host responses and may thereby confer specific advantages to certain bacterial species under changing environmental host conditions.
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Affiliation(s)
- D R Dixon
- Department of Periodontics, University of Washington, Health Sciences Center, Box 357444, Seattle, WA 98195, USA
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Liu D, Cramer CC, Scafidi J, Davis AE. N-linked glycosylation at Asn3 and the positively charged residues within the amino-terminal domain of the c1 inhibitor are required for interaction of the C1 Inhibitor with Salmonella enterica serovar typhimurium lipopolysaccharide and lipid A. Infect Immun 2005; 73:4478-87. [PMID: 16040958 PMCID: PMC1201182 DOI: 10.1128/iai.73.8.4478-4487.2005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The C1 inhibitor (C1INH), a plasma complement regulatory protein, prevents endotoxin shock, at least partially via the direct interaction of its amino-terminal heavily glycosylated nonserpin region with gram-negative bacterial lipopolysaccharide (LPS). To further characterize the potential LPS-binding site(s) within the amino-terminal domain, mutations were introduced into C1INH at the three N-linked glycosylation sites and at the four positively charged amino acid residues. A mutant in which Asn(3) was replaced with Ala was markedly less effective in its binding to LPS, while substitution of Asn(47) or Asn(59) had little effect on binding. The mutation of C1INH at all four positively charged amino acid residues (Arg(18), Lys(22), Lys(30), and Lys(55)) resulted in near-complete failure to interact with LPS. The C1INH mutants that did not bind to LPS also did not suppress LPS binding or LPS-induced up-regulation of tumor necrosis factor alpha mRNA expression in RAW 264.7 macrophages. In addition, the binding of C1INH mutants to diphosphoryl lipid A was decreased in comparison with that of recombinant wild-type C1INH. Therefore, the interaction of C1INH with gram-negative bacterial LPS is dependent both on the N-linked carbohydrate at Asn(3) and on the positively charged residues within the amino-terminal domain.
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Affiliation(s)
- Dongxu Liu
- The CBR Institute for Biomedical Research, Harvard Medical School, 800 Huntington Avenue, Boston, MA 02115, USA
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Sato Y, Shibata KI, Kataoka H, Ogino SI, Bunshi F, Yokoyama A, Tamura K, Akasaka T, Uo M, Motomiya K, Jeyadevan B, Hatakeyama R, Watari F, Tohji K. Strict preparation and evaluation of water-soluble hat-stacked carbon nanofibers for biomedical application and their high biocompatibility: influence of nanofiber-surface functional groups on cytotoxicity. MOLECULAR BIOSYSTEMS 2005; 1:142-5. [PMID: 16880976 DOI: 10.1039/b501222h] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Water-soluble H-CNFs modified with a carboxyl group possessed the ability to induce TNF-alpha, whereas CHAPS-treated H-CNFs possessed significantly greater activity and were also found to activate NF-kappaB reporter activity, to a significantly greater level than H-CNFs; furthermore the functional group modified or coated on the surface of H-CNFs was a significant cytotoxic factor that affected cell activation.
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Affiliation(s)
- Yoshinori Sato
- Graduate School of Environmental Studies, Tohoku Univesity, Aramaki, Sendai, Japan.
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Abstract
Lipopolysaccharide (LPS), shed by gram-negative bacteria during infection and antimicrobial therapy, may lead to lethal endotoxic shock syndrome. A rational design strategy based on the presumed mechanism of antibacterial effect was adopted to design cationic antimicrobial peptides capable of binding to LPS through tandemly repeated sequences of alternating cationic and nonpolar residues. The peptides were designed to achieve enhanced antimicrobial potency due to initial bacterial membrane binding with a reduced risk of endotoxic shock. The peptides designed displayed binding affinities to LPS and lipid A (LA) in the low micromolar range and by molecular modeling were predicted to form amphipathic beta-hairpin-like structures when they bind to LPS or LA. They also exhibited strong effects against gram-negative bacteria, with MICs in the nanomolar range, and low cytotoxic and hemolytic activities at concentrations significantly exceeding their MICs. Quantitative structure-activity relationship (QSAR) analysis of peptide sequences and their antimicrobial, cytotoxic, and hemolytic activities revealed that site-directed substitutions of residues in the hydrophobic face of the amphipathic peptides with less lipophilic residues selectively decrease the hemolytic effect without significantly affecting the antimicrobial or cytotoxic activity. On the other hand, the antimicrobial effect can be enhanced by substitutions in the polar face with more polar residues, which increase the amphipathicity of the peptide. On the basis of the QSARs, new analogs that have strong antimicrobial effects but that lack hemolytic activity can be proposed. The findings highlight the importance of peptide amphipathicity and allow a rational method that can be used to dissociate the antimicrobial and hemolytic effects of cationic peptides, which have potent antimicrobial properties, to be proposed.
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Affiliation(s)
- V Frecer
- Department of Biological Sciences, Faculty of Science, National University of Singapore, 14 Science Dr. 4, Singapore 117543, Republic of Singapore
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Triantafilou M, Brandenburg K, Kusumoto S, Fukase K, Mackie A, Seydel U, Triantafilou K. Combinational clustering of receptors following stimulation by bacterial products determines lipopolysaccharide responses. Biochem J 2004; 381:527-36. [PMID: 15040785 PMCID: PMC1133861 DOI: 10.1042/bj20040172] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 03/15/2004] [Accepted: 03/24/2004] [Indexed: 01/12/2023]
Abstract
The innate immune system has the capacity to recognize a wide range of pathogens based on conserved PAMPs (pathogen-associated molecular patterns). In the case of bacterial LPS (lipopolysaccharide) recognition, the best studied PAMP, it has been shown that the innate immune system employs at least three cell-surface receptors: CD14, TLR4 (Toll-like receptor 4) and MD-2 protein. CD14 binds LPS from Enterobacteriaceae and then transfers it to MD-2, leading to TLR4 aggregation and signal transduction. LPS analogues such as lipid IVa seem to act as LPS antagonists in human cells, but exhibit LPS mimetic activity in mouse cells. Although TLR4 has been shown to be involved in this species-specific discrimination, the mechanism by which this is achieved has not been elucidated. The questions that remain are how the innate immune system can discriminate between LPS from different bacteria as well as different LPS analogues, and whether or not the structure of LPS affects its interaction with the CD14-TLR4-MD-2 cluster. Is it possible that the 'shape' of LPS induces the formation of different receptor clusters, and thus a different immune response? In the present study, we demonstrate using biochemical as well as fluorescence-imaging techniques that different LPS analogues trigger the recruitment of different receptors within microdomains. The composition of each receptor cluster as well as the number of TLR4 molecules that are recruited within the cluster seem to determine whether an immune response will be induced or inhibited.
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Key Words
- innate recognition
- lipopolysaccharide (lps)
- lipopolysaccharide-activation cluster toll-like receptor 4 (tlr4)
- cho, chinese-hamster ovary
- cxcr4, chemokine receptor 4
- frap, fluorescence recovery after photobleaching
- fret, fluorescence resonance energy transfer
- gdf5, growth-differentiation factor 5
- gm-1, monosialoganglioside
- hrp, horseradish peroxidase
- hsp, heat-shock protein
- iκb, inhibitory κb
- jnk, c-jun n-terminal kinase
- lps, lipopolysaccharide
- mab, monoclonal antibody
- mapk, mitogen-activated protein kinase
- meb, membrane-extraction buffer
- mhc, major histocompatibility complex
- mnc, mononuclear cell
- nf-κb, nuclear factor κb
- pbs-t, pbs with tween 20
- pla, penta-acyl lipid a
- sapk, stress-activated protein kinase
- tlr, toll-like receptor
- tnf-α, tumour necrosis factor α
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Affiliation(s)
- Martha Triantafilou
- Infection and Immunity Group, School of Life Sciences, University of Sussex, JMS Building, Falmer, Brighton BN1 9QG, UK.
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Liu D, Gu X, Scafidi J, Davis AE. N-linked glycosylation is required for c1 inhibitor-mediated protection from endotoxin shock in mice. Infect Immun 2004; 72:1946-55. [PMID: 15039314 PMCID: PMC375168 DOI: 10.1128/iai.72.4.1946-1955.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
C1 inhibitor (C1INH) prevents endotoxin shock in mice via a direct interaction with lipopolysaccharide (LPS). This interaction requires the heavily glycosylated amino-terminal domain of C1INH. C1INH in which N-linked carbohydrate was removed by using N-glycosidase F was markedly less effective in protecting mice from LPS-induced lethal septic shock. N-deglycosylated C1INH also failed to suppress fluorescein isothiocyanate (FITC)-LPS binding to and LPS-induced tumor necrosis factor alpha mRNA expression by the murine macrophage-like cell line, RAW 264.7, and cells in human whole blood. In an enzyme linked immunosorbent assay, the N-deglycosylated C1INH bound to LPS very poorly. In addition, C1INH was shown to bind to diphosphoryl lipid A (dLPA) but only weakly to monophosphoryl lipid A (mLPA). As with intact LPS, binding of N-deglycosylated C1INH to dLPA and mLPA was diminished in comparison with the native protein. Removal of O-linked carbohydrate had no effect on any of these activities. Neither detoxified LPS, dLPA, nor mLPA had any effect on the rate or extent of C1INH complex formation with C1s or on cleavage of the reactive center loop by trypsin. These data demonstrate that N-linked glycosylation of C1INH is essential to mediate its interaction with the LPA moiety of LPS and to protect mice from endotoxin shock.
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Affiliation(s)
- Dongxu Liu
- CBR Institute for Biomedical Research, Harvard Medical School, Boston, Massachusetts 02115, USA
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Binding N, Jaschinski S, Werlich S, Bletz S, Witting U. Quantification of bacterial lipopolysaccharides (endotoxin) by GC-MS determination of 3-hydroxy fatty acids. ACTA ACUST UNITED AC 2003; 6:65-70. [PMID: 14737472 DOI: 10.1039/b309237b] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A GC-MS method for the quantification of bacterial lipopolysaccharides (LPS, endotoxin) is presented. After hydrolytic cleavage of 3-hydroxy fatty acids (3-OH FAs) from the lipid A region of LPS, derivatisation of both the hydroxyl and the carboxyl group was performed in one step with a mixture of methyl-bis(trifluoracetamide)(MBTFA) and N-methyl-N-(tert-butyldimethylsilyl)trifluoracetamide (MTBSTFA). Using GC-MS in the EI mode with selected ion monitoring (SIM) for analysis, baseline separation of 3-OH FAs (and of possibly interfering 2-OH FAs) was achieved. The sensitivity of the method (LOD 7-50 pg/injection for the different 3-OH FAs investigated) allows for the efficient quantification of LPS in occupational and environmental samples. Degradation of 3-OH FAs as well as of their derivatives during sample preparation and GC-MS separation as a possible source of errors in analytical methods based on 3-OH FA determination is reported for the first time. Thermal elimination of water from the underivatised 3-OH FAs and of trifluoroacetic acid from the derivatives was identified as the cause of degradation. The resulting alpha,beta-unsaturated compounds showing the same mass spectra as the 3-OH FA derivatives were detected as more or less prominent satellite peaks. By using alkaline instead of acidic hydrolysis and cool on-column instead of split/splitless injection, elimination was reduced to an acceptable level.
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Affiliation(s)
- Norbert Binding
- Institute of Occupational Medicine, University of Münster, Münster D-48149, Germany
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Hashimoto M, Asai Y, Tamai R, Jinno T, Umatani K, Ogawa T. Chemical structure and immunobiological activity of lipid A from Prevotella intermedia ATCC 25611 lipopolysaccharide. FEBS Lett 2003; 543:98-102. [PMID: 12753913 DOI: 10.1016/s0014-5793(03)00414-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The novel chemical structure and immunobiological activities of Prevotella intermedia ATCC 25611 lipid A were investigated. A lipopolysaccharide (LPS) preparation of P. intermedia was extracted using a phenol-chloroform-petroleum ether method, after which its purified lipid A was prepared by weak acid hydrolysis followed by chromatographic separations. The lipid A structure was determined by mass spectrometry and nuclear magnetic resonance to be a diglucosamine backbone with a phosphate at the 4-position of the non-reducing side sugar, as well as five fatty acids containing branched long chains. It was similar to that of Bacteroides fragilis and Porphyromonas gingivalis, except for the phosphorylation site. P. intermedia lipid A induced weaker cytokine production and NF-kappaB activation in murine cells via Toll-like receptor (TLR) 4 as compared to Escherichia coli synthetic lipid A (compound 506). Our results indicate that P. intermedia lipid A activates cells through a TLR4-dependent pathway similar to E. coli-type lipid A, even though these have structural differences.
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Affiliation(s)
- Masahito Hashimoto
- Department of Oral Microbiology, Asahi University School of Dentistry, 1851-1 Hozumi, Mizuho, 501-0296, Gifu, Japan
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Mullarkey M, Rose JR, Bristol J, Kawata T, Kimura A, Kobayashi S, Przetak M, Chow J, Gusovsky F, Christ WJ, Rossignol DP. Inhibition of endotoxin response by e5564, a novel Toll-like receptor 4-directed endotoxin antagonist. J Pharmacol Exp Ther 2003; 304:1093-102. [PMID: 12604686 DOI: 10.1124/jpet.102.044487] [Citation(s) in RCA: 236] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alpha-D-glucopyranose,3-O-decyl-2-deoxy-6-O-[2-deoxy-3-O-[(3R)-3-methoxydecyl]-6-O-methyl-2-[[(11Z)-1-oxo-11-octadecenyl]amino]-4-O-phosphono-beta-D-glucopyranosyl]-2-[(1,3-dioxotetradecyl)amino]-1-(dihydrogen phosphate), tetrasodium salt (E5564) is a second-generation synthetic lipodisaccharide designed to antagonize the toxic effects of endotoxin, a major immunostimulatory component of the outer cell membrane of Gram negative bacteria. In vitro, E5564 dose dependently (nanomolar concentrations) inhibited lipopolysaccharide (LPS)-mediated activation of primary cultures of human myeloid cells and mouse tissue culture macrophage cell lines as well as human or animal whole blood as measured by production of tumor necrosis factor-alpha and other cytokines. E5564 also blocked the ability of Gram negative bacteria to stimulate human cytokine production in whole blood. In vivo, E5564 blocked induction of LPS-induced cytokines and LPS or bacterial-induced lethality in primed mice. E5564 was devoid of agonistic activity when tested both in vitro and in vivo and has no antagonistic activity against Gram positive-mediated cellular activation at concentrations up to 1 microM. E5564 blocked LPS-mediated activation of nuclear factor-kappaB in toll-like receptor 4/MD-2-transfected cells. In a mouse macrophage cell line, activity of E5564 was independent of serum, suggesting that E5564 exerts its activity through the cell surface receptor(s) for LPS, without the need for serum LPS transfer proteins. Similar to (6-O-[2-deoxy-6-O-methyl-4-O-phosphono-3-O-[(R)-3-Z-dodec-5-endoyloxydecl]-2-[3-oxo-tetradecanoylamino]-beta-O-phosphono-alpha-D-glucopyranose tetrasodium salt (E5531), another lipid A-like antagonist, E5564 associates with plasma lipoproteins, causing low concentrations of E5564 to be quantitatively inactivated in a dose- and time-dependent manner. However, compared with E5531, E5564 is a more potent inhibitor of cytokine generation, and higher doses retain activity for durations likely sufficient to permit clinical application. These results indicate that E5564 is a potent antagonist of LPS and lacks agonistic activity in human and animal model systems, making it a potentially effective therapeutic agent for treatment of disease states caused by endotoxin.
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Affiliation(s)
- Maureen Mullarkey
- Biology Section, Eisai Research Institute of Boston, Inc., Andover, Massachusetts, USA
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46
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Novel lipid A mimetics derived from pentaerythritol: synthesis and their potent agonistic activity. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)01067-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Steeghs L, Berns M, ten Hove J, de Jong A, Roholl P, van Alphen L, Tommassen J, van der Ley P. Expression of foreign LpxA acyltransferases in Neisseria meningitidis results in modified lipid A with reduced toxicity and retained adjuvant activity. Cell Microbiol 2002; 4:599-611. [PMID: 12390352 DOI: 10.1046/j.1462-5822.2002.00214.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A major problem in the development of vaccines against Gram-negative bacteria is the endotoxic -activity of lipopolysaccharide (LPS), which is determined by its lipid A moiety. Nevertheless, LPS would be an interesting vaccine component because of its immune-stimulating properties. In the present study, we have changed the fatty acid composition of Neisseria meningitidis LPS by replacing the lpxA gene of strain H44/76 with the Escherichia coli or Pseudomonas aeruginosa homologue. The majority of the O-linked 3-OH C12 in N. meningitidis lipid A was replaced by 3-OH C14 (strain HA01E) and 3-OH C10 (strain HA25P) respectively. Both strains, but most notably strain HA01E, had reduced amounts of LPS compared with the wild-type strain. In addition, growth was severely impaired for HA01E. The major outer membrane proteins were expressed normally. Outer membrane complexes of both strains normalized on their LPS content showed a 10-fold reduction in their ability to induce tumour necrosis factor (TNF)-alpha. Immunogenicity studies in BALB/c mice revealed that the adjuvant activity of the LPS was not affected. Thus, the replacement of the O-linked fatty acids in meningococcal lipid A results in immunogenic outer membranes with reduced endotoxic activity, more suitable for use in outer membrane vesicle vaccines.
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Affiliation(s)
- Liana Steeghs
- Laboratory of Vaccine Research, National Institute of Public Health and the Environment (RIVM), Antonie van Leeuwenhoeklaan 9, PO Box 1, 3720 BA Bilthoven, The Netherlands.
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48
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Jiang ZH, Bach MV, Budzynski WA, Krantz MJ, Koganty RR, Longenecker BM. Lipid A structures containing novel lipid moieties: synthesis and adjuvant properties. Bioorg Med Chem Lett 2002; 12:2193-6. [PMID: 12127535 DOI: 10.1016/s0960-894x(02)00362-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Structurally well-defined immune stimulatory molecules are important components of new generation molecular vaccines. In this paper, the design and synthesis of two lipid A analogues containing an unnatural tri-lipid acyl group are described. In a totally synthetic liposomal vaccine system, these re-designed lipid A analogues demonstrate potent immune stimulatory properties including antigen specific T-cell activation.
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Affiliation(s)
- Zi Hua Jiang
- Biomira Inc., 2011-94 Street, Edmonton, T6N 1H1, Alberta, Canada.
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49
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Abstract
The availability of hundreds of different adjuvants has prompted a need for identifying rational standards for selection of adjuvant formulations based on safety and sound immunological principles for human vaccines. Although many of the mechanisms of adjuvants have been elucidated, meaningful comparisons between different adjuvants derived from in vitro studies, or from studies using adjuvants in rodents or other animals, are often not predictive for safety, adjuvant effects, or vaccine efficacy in humans. A highly efficient and cost-effective method for comparison of adjuvants with a new antigen is to conduct multiple small-scale, phase 1, comparative studies in humans with a new antigen, using adjuvants previously found to be safe with other antigens in human trials. Studies in which highly immunogenic and safe adjuvant formulations have been evaluated in comparative adjuvant trials in humans using a single candidate vaccine antigen against malaria, HIV, and prostate cancer with multiple adjuvants are reviewed.
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Affiliation(s)
- Carl R Alving
- Department of Membrane Biochemistry, Walter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA.
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50
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