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Low-Dose Exposure to Ganglioside-Mimicking Bacteria Tolerizes Human Macrophages to Guillain-Barré Syndrome-Associated Antigens. mBio 2021; 13:e0385221. [PMID: 35100875 PMCID: PMC8805021 DOI: 10.1128/mbio.03852-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Early in life, commensal bacteria play a major role in immune development, helping to guide the host response toward harmful stimuli while tolerating harmless antigens to prevent autoimmunity. Guillain-Barré syndrome (GBS) is an autoimmune disease caused by errant immune attack of antibody-bound ganglioside receptors on host nerve cells, resulting in paralysis. Lipooligosaccharides enveloping the prevalent enteric pathogen, Campylobacter jejuni, frequently mimic human gangliosides and can trigger GBS by stimulating the autoimmune response. In low- to middle-income countries, young children are consistently exposed to C. jejuni, and it is not known if this impacts GBS susceptibility later in life. Using a macrophage model, we examined the effect of training these cells with low doses of ganglioside-mimicking bacteria prior to challenge with GBS-associated antigens. This training caused decreased production of proinflammatory cytokines, suggesting tolerance induction. We then screened Campylobacter isolates from 154 infant fecal samples for GM1 ganglioside mimicry, finding that 23.4% of strains from both symptomatic and asymptomatic infants displayed GM1-like structures. Training macrophages with one of these asymptomatic carrier isolates also induced tolerance against GBS-associated antigens, supporting that children can be exposed to the tolerizing antigen early in life. RNA interference of Toll-like receptor 2 (TLR2) and TLR4 suggests that these receptors are not involved in tolerance associated with decreases in tumor necrosis factor (TNF), interleukin-6 (IL-6), or IL-1β levels. The results of this study suggest that exposure to ganglioside-mimicking bacteria early in life occurs naturally and impacts host susceptibility to GBS development. IMPORTANCE In this study, we demonstrated that it is possible to tolerize immune cells to potentially dampen the autoreactive proinflammatory immune response against Guillain-Barré syndrome (GBS)-associated antigens. The innate immune response functions to arm the host against bacterial attack, but it can be tricked into recognizing the host's own cells when infectious bacteria display sugar structures that mimic human glycans. It is this errant response that leads to the autoimmunity and paralysis associated with GBS. By presenting immune cells with small amounts of the bacterial glycan mimic, we were able to suppress the proinflammatory immune response upon subsequent high exposure to glycan-mimicking bacteria. This suggests that individuals who have already been exposed to the glycan mimics in small amounts are less sensitive to autoimmune reactions against these glycans, and this could be a factor in determining susceptibility to GBS.
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Nelson NLJ, Zajd CM, Lennartz MR, Gosselin EJ. Fcγ receptors and toll-like receptor 9 synergize to drive immune complex-induced dendritic cell maturation. Cell Immunol 2019; 345:103962. [PMID: 31582169 DOI: 10.1016/j.cellimm.2019.103962] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 07/30/2019] [Accepted: 08/03/2019] [Indexed: 12/11/2022]
Abstract
Previous in vivo studies established that inactivated Francisella tularensis immune complexes (mAb-iFt) are a more protective vaccine against lethal tularemia than iFt alone. Subsequent in vitro studies revealed enhanced DC maturation marker expression with mAb-iFt stimulation. The goal of this study was to determine the mechanism of enhanced DC maturation. Multiparameter analysis of surface marker expression and cytokine secretion demonstrates a requirement for FcγR signaling in enhanced DC maturation. MyD88 was also found to be essential for heightened DC maturation, implicating MyD88-dependent TLRs in DC maturation. Upon further study, we discovered that TLRs 2 & 4 drive cytokine secretion, but surprisingly TLR9 is required for DC maturation marker upregulation. These studies reveal a separation of DC cytokine and maturation marker induction pathways and demonstrate that FcγR-TLR/MyD88 synergy underlies the enhanced dendritic cell maturation in response to the mAb-iFt vaccine.
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Affiliation(s)
- Nicole L J Nelson
- Department of Immunology and Microbial Disease, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, United States.
| | - Cheryl M Zajd
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, United States
| | - Michelle R Lennartz
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, United States
| | - Edmund J Gosselin
- Department of Immunology and Microbial Disease, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208, United States.
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3
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Battin C, Hennig A, Mayrhofer P, Kunert R, Zlabinger GJ, Steinberger P, Paster W. A human monocytic NF-κB fluorescent reporter cell line for detection of microbial contaminants in biological samples. PLoS One 2017; 12:e0178220. [PMID: 28542462 PMCID: PMC5443541 DOI: 10.1371/journal.pone.0178220] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/09/2017] [Indexed: 12/16/2022] Open
Abstract
Sensing of pathogens by innate immune cells is essential for the initiation of appropriate immune responses. Toll-like receptors (TLRs), which are highly sensitive for various structurally and evolutionary conserved molecules derived from microbes have a prominent role in this process. TLR engagement results in the activation of the transcription factor NF-κB, which induces the expression of cytokines and other inflammatory mediators. The exquisite sensitivity of TLR signalling can be exploited for the detection of bacteria and microbial contaminants in tissue cultures and in protein preparations. Here we describe a cellular reporter system for the detection of TLR ligands in biological samples. The well-characterized human monocytic THP-1 cell line was chosen as host for an NF-ᴋB-inducible enhanced green fluorescent protein reporter gene. We studied the sensitivity of the resultant reporter cells for a variety of microbial components and observed a strong reactivity towards TLR1/2 and TLR2/6 ligands. Mycoplasma lipoproteins are potent TLR2/6 agonists and we demonstrate that our reporter cells can be used as reliable and robust detection system for mycoplasma contaminations in cell cultures. In addition, a TLR4-sensitive subline of our reporters was engineered, and probed with recombinant proteins expressed in different host systems. Bacterially expressed but not mammalian expressed proteins induced strong reporter activity. We also tested proteins expressed in an E. coli strain engineered to lack TLR4 agonists. Such preparations also induced reporter activation in THP-1 cells highlighting the importance of testing recombinant protein preparations for microbial contaminations beyond endotoxins. Our results demonstrate the usefulness of monocytic reporter cells for high-throughput screening for microbial contaminations in diverse biological samples, including tissue culture supernatants and recombinant protein preparations. Fluorescent reporter assays can be measured on standard flow cytometers and in contrast to established detection methods, like luciferase-based systems or Limulus Amebocyte Lysate tests, they do not require costly reagents.
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Affiliation(s)
- Claire Battin
- Division of Immune Receptors and T Cell Activation, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Annika Hennig
- Division of Immune Receptors and T Cell Activation, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Patrick Mayrhofer
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Renate Kunert
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Gerhard J. Zlabinger
- Division of Clinical and Experimental Immunology, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Peter Steinberger
- Division of Immune Receptors and T Cell Activation, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- * E-mail: (PS); (WP), (WP)
| | - Wolfgang Paster
- Division of Immune Receptors and T Cell Activation, Institute of Immunology, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
- * E-mail: (PS); (WP), (WP)
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4
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Zandieh Z, Ashrafi M, Jameie B, Amanpour S, Mosaffa N, Salman Yazdi R, Pacey A, Aflatoonian R. Evaluation of immunological interaction between spermatozoa and fallopian tube epithelial cells. Andrologia 2015; 47:1120-30. [DOI: 10.1111/and.12391] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2014] [Indexed: 12/12/2022] Open
Affiliation(s)
- Z. Zandieh
- Anatomy Department; School of Medicine; Iran University of Medical Sciences; Tehran Iran
| | - M. Ashrafi
- Obstetrics and Gynecology Department; School of Medicine; Iran University of Medical Sciences; Tehran Iran
| | - B. Jameie
- Anatomy Department; School of Medicine; Iran University of Medical Sciences; Tehran Iran
| | - S. Amanpour
- Valie-Asr Reproductive Health Research Center; Tehran University of Medical Sciences; Tehran Iran
| | - N. Mosaffa
- Department of Immunology; Faculty of Medicine; Shaheed Beheshti University of Medical Sciences; Tehran Iran
| | - R. Salman Yazdi
- Department of Andrology at Reproductive Biomedicine Research Center; Royan Institute for Reproductive Biomedicine; ACECR; Tehran Iran
| | - A. Pacey
- Academic Unit of Reproductive and Developmental Medicine; University of Sheffield; Sheffield UK
| | - R. Aflatoonian
- Department of Endocrinology and Female Infertility at Reproductive Biomedicine Research Center; Royan Institute for Reproductive Biomedicine; ACECR; Tehran Iran
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5
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Ogura N, Muroi M, Sugiura Y, Tanamoto KI. Lipid IVa incompletely activates MyD88-independent Toll-like receptor 4 signaling in mouse macrophage cell lines. Pathog Dis 2013; 67:199-205. [DOI: 10.1111/2049-632x.12031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/29/2013] [Accepted: 01/31/2013] [Indexed: 10/27/2022] Open
Affiliation(s)
- Norihiko Ogura
- Research Institute of Pharmaceutical Sciences; Musashino University; Tokyo; Japan
| | - Masashi Muroi
- Research Institute of Pharmaceutical Sciences; Musashino University; Tokyo; Japan
| | - Yuka Sugiura
- Research Institute of Pharmaceutical Sciences; Musashino University; Tokyo; Japan
| | - Ken-ichi Tanamoto
- Research Institute of Pharmaceutical Sciences; Musashino University; Tokyo; Japan
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6
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Intrinsic nitric oxide-stimulatory activity of lipoteichoic acids from different Gram-positive bacteria. Nitric Oxide 2010; 23:300-10. [DOI: 10.1016/j.niox.2010.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 08/24/2010] [Accepted: 09/08/2010] [Indexed: 11/16/2022]
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Alhawi M, Stewart J, Erridge C, Patrick S, Poxton IR. Bacteroides fragilis signals through Toll-like receptor (TLR) 2 and not through TLR4. J Med Microbiol 2009; 58:1015-1022. [PMID: 19528164 DOI: 10.1099/jmm.0.009936-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although it is desirable to identify the interactions between endotoxin/LPS and the innate immune mechanism, it is often not possible to isolate these interactions from other cell wall-related structures of protein or polysaccharide origin. There is no universally accepted method to extract different LPSs from different bacteria, and their natural state will be influenced by their interactions with the associated molecules in the bacterial outer membrane. It is now believed that Toll-like receptor (TLR) 4 is the main signal transducer of classical LPS (i.e. Escherichia coli LPS), while TLR2 is used by certain non-classical LPSs. There are contradictory reports as to whether Bacteroides fragilis LPS, a non-classical LPS, signals primarily through TLR2 or TLR4. This study was designed to address this problem. Different non-purified and purified B. fragilis LPSs extracted by different methods together with different heat-killed, whole-cell populations of B. fragilis were used to elucidate the TLR specificity. All of these B. fragilis preparations showed a significant signalling specificity for TLR2 but not for TLR4. This indicates that changing the extraction methods, with or without applying a repurification procedure, and varying the cell populations do not alter the TLR specificity of B. fragilis LPS.
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Affiliation(s)
- Mohammad Alhawi
- Medical Microbiology, Centre for Infectious Diseases, University of Edinburgh College of Medicine and Veterinary Medicine, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - John Stewart
- Medical Microbiology, Centre for Infectious Diseases, University of Edinburgh College of Medicine and Veterinary Medicine, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Clett Erridge
- Department of Cardiovascular Sciences, University of Leicester, Clinical Science Wing, Glenfield General Hospital, Leicester LE3 9QP, UK
| | - Sheila Patrick
- Centre for Infection and Immunity, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
| | - Ian R Poxton
- Medical Microbiology, Centre for Infectious Diseases, University of Edinburgh College of Medicine and Veterinary Medicine, Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
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Ghosh M, Schaefer TM, Fahey JV, Wright JA, Wira CR. Antiviral responses of human Fallopian tube epithelial cells to toll-like receptor 3 agonist poly(I:C). Fertil Steril 2007; 89:1497-506. [PMID: 17669408 PMCID: PMC2647142 DOI: 10.1016/j.fertnstert.2007.05.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 05/11/2007] [Accepted: 05/11/2007] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To examine the expression of toll-like receptors (TLR) by primary human Fallopian tube epithelial cells (FTEC) and to determine whether exposure to the TLR3 agonist poly(I:C) induces an antiviral response. DESIGN Tissue culture study. SETTING University medical center. PATIENT(S) Premenopausal women undergoing hysterectomy. INTERVENTION(S) Primary human FTEC were grown to confluence and high transepithelial resistance and treated with TLR agonists. Conditioned media was collected and RNA was extracted and analyzed for the expression of cytokines, chemokines, and antimicrobial genes. MAIN OUTCOME MEASURE(S) The RNA was analyzed by real-time polymerase chain reaction and protein levels were assessed by enzyme-linked immunosorbent assay. RESULT(S) The FTEC were demonstrated to express TLR1-9 but not 10. Treatment of FTEC with TLR3 agonist poly(I:C) resulted in increased expression of interleukin-8, tumor-necrosis factor alpha, human beta-defensin 2, interferon beta, and interferon stimulated genes myxovirus resistance gene 1, 2',5'-oligoadenylate synthetase, and protein kinase R. Additionally, FTEC exposed to poly(I:C) also resulted in the induction of TLR2, TLR3, and TLR7. CONCLUSION(S) Our results suggest that FTEC are sensitive to viral infection and/or exposure to viral double-stranded RNA and can respond by secreting proinflammatory cytokines that mediate the initiation of an inflammatory response as well as expressing genes that can directly inhibit viral replication.
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Affiliation(s)
- Mimi Ghosh
- Department of Physiology, Dartmouth Medical School, Lebanon, New Hampshire 03756, USA.
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Spiller S, Dreher S, Meng G, Grabiec A, Thomas W, Hartung T, Pfeffer K, Hochrein H, Brade H, Bessler W, Wagner H, Kirschning CJ. Cellular recognition of trimyristoylated peptide or enterobacterial lipopolysaccharide via both TLR2 and TLR4. J Biol Chem 2007; 282:13190-8. [PMID: 17353199 DOI: 10.1074/jbc.m610340200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Evidence for specific and direct bacterial product recognition through toll-like receptors (TLRs) has been emphasized recently. We analyzed lipopeptide analogues and enterobacterial lipopolysaccharide (eLPS) for their potential to activate cells through TLR2 and TLR4. Whereas bacterial protein palmitoylated at its N-terminal cysteine and N-terminal peptides derived thereof are known to induce TLR2-mediated cell activation, a synthetic acylhexapeptide mimicking a bacterial lipoprotein subpopulation for which N-terminal trimyristoylation is characteristic (Myr(3)CSK(4)) activated cells not only through TLR2 but also through TLR4. Conversely, highly purified eLPS triggered cell activation through overexpressed TLR2 in the absence of TLR4 expression if CD14 was coexpressed. Accordingly, TLR2(-/-) macrophages prepared upon gene targeting responded to Myr(3)CSK(4) challenge, whereas TLR2(-/-)/TLR4(d/d) cells were unresponsive. Through interferon-gamma (IFNgamma) priming, macrophages lacking expression of functional TLR4 and/or MD-2 acquired sensitivity to eLPS, whereas TLR2/TLR4 double deficient cells did not. Not only TLR2(-/-) mice but also TLR4(-/-) mice were resistant to Myr(3)CSK(4) challenge-induced fatal shock. d-Galactosamine-sensitized mice expressing defective TLR4 or lacking TLR4 expression acquired susceptibility to eLPS-driven toxemia upon IFNgamma priming, whereas double deficient mice did not. Immunization toward ovalbumin using Myr(3)CSK(4) as adjuvant was ineffective in TLR2(-/-)/TLR4(-/-) mice yet effective in wild-type, TLR2(-/-), or TLR4(-/-) mice as shown by analysis of ovalbumin-specific serum Ig concentration. A compound such as Myr(3)CSK(4) whose stimulatory activity is mediated by both TLR2 and TLR4 might constitute a preferable adjuvant. On the other hand, simultaneous blockage of both of the two TLRs might effectively inhibit infection-induced pathology.
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Affiliation(s)
- Stephan Spiller
- Institute of Medical Microbiology, Immunology, and Hygiene, Technical University of Munich, 81675 Munich, Germany
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10
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Fehrenbach K, Port F, Grochowy G, Kalis C, Bessler W, Galanos C, Krystal G, Freudenberg M, Huber M. Stimulation of mast cells via FcvarepsilonR1 and TLR2: the type of ligand determines the outcome. Mol Immunol 2006; 44:2087-94. [PMID: 17095089 DOI: 10.1016/j.molimm.2006.09.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 09/08/2006] [Accepted: 09/08/2006] [Indexed: 11/27/2022]
Abstract
Little is known about the interplay between pathophysiological processes of allergy and infection, particularly with respect to mast cell (MC)-mediated responses. The presence and recognition of pathogen-associated molecular patterns (PAMPs) might have broad impact on the development and severity of diseases. In this study, we assessed the influence of toll-like receptor 2 (TLR 2)-dependent synthetic analogs of bacterial lipopeptides (LPs), Pam(3)CSK(4) and MALP-2, on Ag (DNP-HSA)-triggered responses in bone marrow-derived MCs (BMMCs). Both LPs strongly synergized with sub-optimal amounts of Ag in the stimulation of cytokine release. Intriguingly, Pam(3)CSK(4), but not MALP-2 suppressed Ag-induced degranulation of BMMCs (together with early tyrosine phosphorylation and calcium mobilization) in a TLR2-independent manner. Further analysis revealed that Pam(3)CSK(4), most probably by electrostatic forces, reduced the level of active DNP-HSA and that this, in turn, was responsible for the suppression of Ag-induced degranulation. Thus, our work demonstrates that LPs can synergize with IgE+Ag in stimulating the production of IL-6 by BMMCs. As well, our findings with Pam(3)CSK(4) indicate that one must be cautious when interpretating results obtained with "model" substances and the combination of ligands must be carefully chosen when functional interactions between the high-affinity receptor for IgE (FcepsilonR1) and TLR2 are examined.
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Affiliation(s)
- Kerstin Fehrenbach
- Department of Molecular Immunology, Biology III, University of Freiburg, Stübeweg 51, 79108 Freiburg, Germany
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11
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Baroni A, Orlando M, Donnarumma G, Farro P, Iovene MR, Tufano MA, Buommino E. Toll-like receptor 2 (TLR2) mediates intracellular signalling in human keratinocytes in response to Malassezia furfur. Arch Dermatol Res 2005; 297:280-8. [PMID: 16283346 DOI: 10.1007/s00403-005-0594-4] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 07/21/2005] [Accepted: 07/26/2005] [Indexed: 10/25/2022]
Abstract
Toll-like receptors (TLRs) are crucial players in the innate immune response to microbial invaders. The lipophilic yeast Malassezia furfur has been implicated in the triggering of scalp lesions in psoriasis. The aim of the present study was to assess the role of TLRs in the defence against M. furfur infection. The expression of the myeloid differentiation factor 88 (MyD88) gene, which is involved in the signalling pathway of many TLRs, was also analysed. In addition, a possible correlation of antimicrobial peptides of the beta-defensin family to TLRs was tested. Human keratinocytes infected with M. furfur and a variety of M. furfur-positive psoriatic skin biopsies were analysed by RT-PCR, for TLRs, MyD88, human beta-defensin 2 (HBD-2), HBD-3 and interleukin-8 (IL-8) mRNA expression. When keratinocytes were infected with M. furfur, an up-regulation for TLR2, MyD88, HBD-2, HBD-3 and IL-8 mRNA was demonstrated, compared to the untreated cells. The same results were obtained when psoriatic skin biopsies were analysed. The M. furfur-induced increase in HBD-2 and IL-8 gene expression is inhibited by anti-TLR2 neutralising antibodies, suggesting that TLR2 is involved in the M. furfur-induced expression of these molecules. These findings suggest the importance of TLRs in skin protection against fungi and the importance of keratinocytes as a component of innate immunity.
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Affiliation(s)
- Adone Baroni
- Department of Dermatology, Faculty of Medicine and Surgery, Second University of Naples, Naples, Italy
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12
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Mancuso G, Midiri A, Biondo C, Beninati C, Gambuzza M, Macrì D, Bellantoni A, Weintraub A, Espevik T, Teti G. Bacteroides fragilis-derived lipopolysaccharide produces cell activation and lethal toxicity via toll-like receptor 4. Infect Immun 2005; 73:5620-7. [PMID: 16113279 PMCID: PMC1231095 DOI: 10.1128/iai.73.9.5620-5627.2005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Bacteroides fragilis, which is part of the normal intestinal flora, is a frequent cause of serious disease, especially in diabetic and surgical patients. In these conditions, B. fragilis lipopolysaccharide (LPS) is likely to play a major pathophysiologic role. B. fragilis LPS is structurally different from classical enterobacterial LPS, whose biological activities are mediated by Toll-like receptor 4 (TLR4) activation. The ability of B. fragilis LPS to activate TLR4 and TLR2 was investigated here, since evidence on this issue is scarce and controversial. Each of four different protein-free B. fragilis LPS preparations could induce interleukin-8 responses in cells cotransfected with TLR4/CD14/MD2 but not TLR4/CD14 alone. Two of the preparations also induced cytokine production in cells cotransfected with TLR2/CD14 or in peritoneal macrophages from TLR4 mutant C3H/HeJ mice. Both of these activities, however, were lost after repurification with a modified phenol reextraction procedure. Importantly, all preparations could induce endotoxic shock in TLR2-deficient mice, but not in TLR4 mutant C3H/HeJ mice. Consistent with these findings, anti-TLR4 and anti-CD14, but not anti-TLR2, antibodies could inhibit B. fragilis LPS-induced cytokine production in human monocytes. Collectively, these results indicate that B. fragilis LPS signals via a TLR4/CD14/MD2-dependent pathway, and it is unable to activate TLR2. Moreover, our data document the occurrence of TLR2-activating contaminants even in highly purified B. fragilis LPS preparations. This may explain earlier contradictory findings on the ability of B. fragilis LPS to activate cells in the absence of functional TLR4. These data may be useful to devise strategies to prevent the pathophysiologic changes observed during B. fragilis sepsis and to better understand structure-activity relationships of LPS.
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MESH Headings
- Adult
- Animals
- Bacteroides Infections/immunology
- Bacteroides Infections/metabolism
- Bacteroides fragilis/immunology
- Cell Line
- Cytokines/metabolism
- Humans
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/metabolism
- Lipopolysaccharides/immunology
- Lipopolysaccharides/toxicity
- Macrophage Activation/immunology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Male
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Knockout
- Monocytes/immunology
- Monocytes/metabolism
- Receptors, Immunologic/deficiency
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Signal Transduction/immunology
- Toll-Like Receptor 2
- Toll-Like Receptor 4
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Affiliation(s)
- Giuseppe Mancuso
- Department of Pathology and Experimental Microbiology, University of Messina, Messina, Italy
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Park JY, Kim HY, Lee JY, Kim KH, Jang MK, Lee JH, Yoo JY, Han DS, Hahm JS. Macrolide-affected Toll-like receptor 4 expression from Helicobacter pylori-infected monocytes does not modify interleukin-8 production. ACTA ACUST UNITED AC 2005; 44:171-6. [PMID: 15866212 DOI: 10.1016/j.femsim.2005.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2004] [Revised: 01/23/2005] [Accepted: 01/25/2005] [Indexed: 01/15/2023]
Abstract
Macrolide antibiotics have an anti-inflammatory effect by suppressing lipopolysaccharide-induced IL-8 production. IL-8 secretion from monocytes is observed in Helicobacter pylori infection. Although cag gene products are known to induce IL-8 secretion, whether other bacterial substances can initiate the reaction is not determined. In this study, we show that clarithromycin induced down-regulation of Toll-like receptor 4 expression and did not lead to a decrease in IL-8 production and H. pylori lipopolysaccharide. However, Toll-like receptor 4 activation was possibly not the main cause in the induction of inflammation during H. pylori infection.
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Affiliation(s)
- Joon Yong Park
- Department of Internal Medicine, Kangdong Sacred Heart Hospital, Hallym University, 445 Gil dong Gangdong-gu, Seoul 134-701, Republic of Korea
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14
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Schaefer TM, Fahey JV, Wright JA, Wira CR. Innate immunity in the human female reproductive tract: antiviral response of uterine epithelial cells to the TLR3 agonist poly(I:C). THE JOURNAL OF IMMUNOLOGY 2005; 174:992-1002. [PMID: 15634923 DOI: 10.4049/jimmunol.174.2.992] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The objective of this study was to examine the expression of TLR by human primary uterine epithelial cells (UEC) and to determine whether exposure to the TLR agonist poly(I:C) would induce an antiviral response. The secretion of several cytokines and chemokines was examined as well as the mRNA expression of human beta-defensin-1 and -2 (HBD1 and HBD2), IFN-beta, and the IFN-beta-stimulated genes myxovirus resistance gene 1 and 2',5' oligoadenylate synthetase. The expression of TLR1-9 by UEC was demonstrated by RT-PCR, with only TLR10 not expressed. Stimulation of UEC with the TLR3 agonist poly(I:C) induced the expression of the proinflammatory cytokines TNF-alpha, IL-6, GM-CSF, and G-CSF, as well as the chemokines CXCL8/IL-8, CCL2/MCP-1, and CCL4/MIP-1beta. In addition, poly(I:C) exposure induced the mRNA expression of HBD1 and HBD2 by 6- and 4-fold, respectively. Furthermore, upon exposure to poly(I:C) UEC initiated a potent antiviral response resulting in the induction of IFN-beta mRNA expression 70-fold and myxovirus resistance gene 1 and 2',5' oligoadenylate synthetase mRNA expression (107- and 96-fold), respectively. These results suggest that epithelial cells that line the uterine cavity are sensitive to viral infection and/or exposure to viral dsRNA released from killed epithelial cells. Not only do UEC release proinflammatory cytokines and chemokines that mediate the initiation of an inflammatory response and recruitment of immune cells to the site of infection, but they also express beta-defensins, IFN-beta, and IFN-beta-stimulated genes that can have a direct inhibiting effect on viral replication.
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Affiliation(s)
- Todd M Schaefer
- Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756, USA.
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Zamboni DS, Campos MA, Torrecilhas ACT, Kiss K, Samuel JE, Golenbock DT, Lauw FN, Roy CR, Almeida IC, Gazzinelli RT. Stimulation of toll-like receptor 2 by Coxiella burnetii is required for macrophage production of pro-inflammatory cytokines and resistance to infection. J Biol Chem 2004; 279:54405-15. [PMID: 15485838 DOI: 10.1074/jbc.m410340200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Innate and adaptive immune responses are initiated upon recognition of microbial molecules by Toll-like receptors (TLRs). We have investigated the importance of these receptors in the induction of pro-inflammatory cytokines and macrophage resistance to infection with Coxiella burnetii, an obligate intracellular bacterium and the etiological agent of Q fever. By using a Chinese hamster ovary/CD14 cell line expressing either functional TLR2 or TLR4, we determined that C. burnetii phase II activates TLR2 but not TLR4. Macrophages deficient for TLR2, but not TLR4, produced less tumor necrosis factor-alpha and interleukin-12 upon C. burnetii infection. Furthermore, it was found that TLR2 activation interfered with C. burnetii intracellular replication, as macrophages from TLR2-deficient mice were highly permissive for C. burnetii growth compared with macrophages from wild type mice or TLR4-deficient mice. Although LPS modifications distinguish virulent C. burnetii phase I bacteria from avirulent phase II organisms, electrospray ionization-mass spectrometry analysis showed that the lipid A moieties isolated from these two phase variants are identical. Purified lipid A derived from either phase I or phase II LPS failed to activate TLR2 and TLR4. Indeed, the lipid A molecules were able to interfere with TLR4 signaling in response to purified Escherichia coli LPS. These studies indicate that TLR2 is an important host determinant that mediates recognition of C. burnetii and a response that limits growth of this intracellular pathogen.
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Affiliation(s)
- Dario S Zamboni
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
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Schaefer TM, Desouza K, Fahey JV, Beagley KW, Wira CR. Toll-like receptor (TLR) expression and TLR-mediated cytokine/chemokine production by human uterine epithelial cells. Immunology 2004; 112:428-36. [PMID: 15196211 PMCID: PMC1782499 DOI: 10.1111/j.1365-2567.2004.01898.x] [Citation(s) in RCA: 251] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The objective of this study was to examine the expression of toll-like receptors (TLRs) by the uterine epithelial cell line ECC-1 and to determine if stimulation of the expressed TLRs induces changes in cytokine and/or chemokine secretion. The expression of TLR1 to TLR9 by ECC-1 cells was demonstrated by reverse transcription polymerase chain reaction, with only TLR10 not being expressed. Stimulation of ECC-1 cells using agonists to TLR2, TLR4 and TLR5 induced the expression of the chemokines interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1), as well as the pro-inflammatory cytokine IL-6, and occurred in a dose-dependent manner. In response to zymosan and flagellin, pathogen-associated molecular patterns (PAMP) that are recognized by TLR2 and TLR5 respectively, ECC-1 cells secreted significantly more IL-8, MCP-1 and IL-6 than in response to other TLR agonists. In contrast, agonists to TLR3, TLR7, and TLR9 had no effect on the secretion of the 13 cytokines or chemokines analysed. These results indicate that uterine epithelial cells are important sentinels of the innate immune system. Further it indicates that all but one of the known TLRs are expressed by ECC-1 cells and that stimulation through specific TLRs mediates changes in the expression of key chemokines and pro-inflammatory cytokines that aid in the defence of the uterus against potential pathogens.
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Affiliation(s)
- Todd M Schaefer
- Department of Physiology, Dartmouth Medical School, Lebanon, NH 03756, USA.
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Fujihara M, Muroi M, Tanamoto KI, Suzuki T, Azuma H, Ikeda H. Molecular mechanisms of macrophage activation and deactivation by lipopolysaccharide: roles of the receptor complex. Pharmacol Ther 2004; 100:171-94. [PMID: 14609719 DOI: 10.1016/j.pharmthera.2003.08.003] [Citation(s) in RCA: 422] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Bacterial lipopolysaccharide (LPS), the major structural component of the outer wall of Gram-negative bacteria, is a potent activator of macrophages. Activated macrophages produce a variety of inflammatory cytokines. Excessive production of cytokines in response to LPS is regarded as the cause of septic shock. On the other hand, macrophages exposed to suboptimal doses of LPS are rendered tolerant to subsequent exposure to LPS and manifest a profoundly altered response to LPS. Increasing evidence suggests that monocytic cells from patients with sepsis and septic shock survivors have characteristics of LPS tolerance. Thus, an understanding of the molecular mechanisms underlying activation and deactivation of macrophages in response to LPS is important for the development of therapeutics for septic shock and the treatment of septic shock survivors. Over the past several years, significant progress has been made in identifying and characterizing several key molecules and signal pathways involved in the regulation of macrophage functions by LPS. In this paper, we summarize the current findings of the functions of the LPS receptor complex, which is composed of CD14, Toll-like receptor 4 (TLR4), and myeloid differentiation protein-2 (MD-2), and the signal pathways of this LPS receptor complex with regard to both activation and deactivation of macrophages by LPS. In addition, recent therapeutic approaches for septic shock targeting the LPS receptor complex are described.
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Affiliation(s)
- Mitsuhiro Fujihara
- Japanese Red Cross, Hokkaido Red Cross Blood Center, Yamanote 2-2, Nishi-ku, Sapporo 063-0002, Japan.
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Lotz S, Aga E, Wilde I, van Zandbergen G, Hartung T, Solbach W, Laskay T. Highly purified lipoteichoic acid activates neutrophil granulocytes and delays their spontaneous apoptosis via CD14 and TLR2. J Leukoc Biol 2003; 75:467-77. [PMID: 14673018 DOI: 10.1189/jlb.0803360] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Lipoteichoic acid (LTA) is a major component of the cell membrane of gram-positive bacteria. Although LTA has become increasingly recognized as an immunomodulator, its effect on polymorphonuclear neutrophil granulocytes (PMN) is still not clear. The interaction between LTA and PMN, however, is of particular importance, as PMN are the first leukocytes that migrate to the site of infection and encounter bacterial pathogens. In the present study, the interaction of highly purified human PMN with endotoxin-free LTA from Staphylococcus aureus was investigated. After exposure to LTA, neutrophil granulocytes acquired typical activated cell morphology. LTA had a marked activating effect on the functions of PMN as well. Shedding of CD62L, degranulation, and priming for formyl-Met-Leu-Phe-mediated oxidative burst were induced in PMN upon exposure to LTA. Moreover, LTA treatment induced the release of proinflammatory cytokines such as interleukin-8, tumor necrosis factor alpha, and granulocyte-colony stimulating factor by PMN. The effects of LTA on PMN were found to be associated with nuclear factor-kappaB activation. Of particular interest was that LTA inhibited the spontaneous apoptosis and therefore, increased the lifespan of PMN. Experiments using blocking antibodies revealed that CD14 and Toll-like receptor 2 (TLR2) but not TLR4 play a major role in LTA-mediated effects on PMN. These data clearly show that LTA, a component of gram-positive bacteria, directly activates neutrophil granulocytes, the primary effector cells in the first line of defense against infectious challenge.
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Affiliation(s)
- Sonja Lotz
- Institute for Medical Microbiology and Hygiene, University of Lübeck, Germany
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