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Im J, Baik JE, Lee D, Park OJ, Park DH, Yun CH, Han SH. Bacterial Lipoproteins Induce BAFF Production via TLR2/MyD88/JNK Signaling Pathways in Dendritic Cells. Front Immunol 2020; 11:564699. [PMID: 33123136 PMCID: PMC7566273 DOI: 10.3389/fimmu.2020.564699] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 09/17/2020] [Indexed: 11/13/2022] Open
Abstract
B-cell activating factor (BAFF) plays a crucial role in survival, differentiation, and antibody secretion of B cells. Microbial products with B-cell mitogenic properties can indirectly promote expansion and activation of B cells by stimulating accessory cells, such as dendritic cells (DCs), to induce BAFF. Although bacterial lipoproteins are potent B-cell mitogen like lipopolysaccharides (LPSs), it is uncertain whether they can stimulate DCs to induce BAFF expression. Here, we evaluated the effect of bacterial lipoproteins on BAFF expression in mouse bone marrow-derived DCs. Lipoprotein-deficient Staphylococcus aureus mutant induced relatively low expression level of membrane-bound BAFF (mBAFF) and the mRNA compared with its wild-type strain, implying that bacterial lipoproteins can positively regulate BAFF induction. The synthetic lipopeptides Pam2CSK4 and Pam3CSK4, which mimic bacterial lipoproteins, dose-dependently induced BAFF expression, and their BAFF-inducing capacities were comparable to those of LPS in DCs. Induction of BAFF by the lipopeptide was higher than the induction by other microbe-associated molecular patterns, including peptidoglycan, flagellin, zymosan, lipoteichoic acid, and poly(I:C). Pam3CSK4 induced both mBAFF and soluble BAFF expression in a dose- and time-dependent manner. BAFF expression by Pam3CSK4 was completely absent in DCs from TLR2- or MyD88-deficient mice. Among various MAP kinase inhibitors, only JNK inhibitors blocked Pam3CSK4-induced BAFF mRNA expression, while inhibitors blocking ERK or p38 kinase had no such effect. Furthermore, Pam3CSK4 increased the DNA-binding activities of NF-κB and Sp1, but not that of C/EBP. Pam3CSK4-induced BAFF promoter activity via TLR2/1 was blocked by NF-κB or Sp1 inhibitor. Collectively, these results suggest that bacterial lipoproteins induce expression of BAFF through TLR2/MyD88/JNK signaling pathways leading to NF-κB and Sp1 activation in DCs, and BAFF derived from bacterial lipoprotein-stimulated DCs induces B-cell proliferation.
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Affiliation(s)
- Jintaek Im
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Jung Eun Baik
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Dongwook Lee
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Ok-Jin Park
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Dong Hyun Park
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, South Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, South Korea
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Sahasrabudhe NM, Beukema M, Tian L, Troost B, Scholte J, Bruininx E, Bruggeman G, van den Berg M, Scheurink A, Schols HA, Faas MM, de Vos P. Dietary Fiber Pectin Directly Blocks Toll-Like Receptor 2-1 and Prevents Doxorubicin-Induced Ileitis. Front Immunol 2018; 9:383. [PMID: 29545800 PMCID: PMC5839092 DOI: 10.3389/fimmu.2018.00383] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 02/12/2018] [Indexed: 12/14/2022] Open
Abstract
Dietary carbohydrate fibers are known to prevent immunological diseases common in Western countries such as allergy and asthma but the underlying mechanisms are largely unknown. Until now beneficial effects of dietary fibers are mainly attributed to fermentation products of the fibers such as anti-inflammatory short-chain fatty acids (SCFAs). Here, we found and present a new mechanism by which dietary fibers can be anti-inflammatory: a commonly consumed fiber, pectin, blocks innate immune receptors. We show that pectin binds and inhibits, toll-like receptor 2 (TLR2) and specifically inhibits the proinflammatory TLR2-TLR1 pathway while the tolerogenic TLR2-TLR6 pathway remains unaltered. This effect is most pronounced with pectins having a low degree of methyl esterification (DM). Low-DM pectin interacts with TLR2 through electrostatic forces between non-esterified galacturonic acids on the pectin and positive charges on the TLR2 ectodomain, as confirmed by testing pectin binding on mutated TLR2. The anti-inflammatory effect of low-DM pectins was first studied in human dendritic cells and mouse macrophages in vitro and was subsequently tested in vivo in TLR2-dependent ileitis in a mouse model. In these mice, ileitis was prevented by pectin administration. Protective effects were shown to be TLR2-TLR1 dependent and independent of the SCFAs produced by the gut microbiota. These data suggest that low-DM pectins as a source of dietary fiber can reduce inflammation through direct interaction with TLR2-TLR1 receptors.
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Affiliation(s)
- Neha M. Sahasrabudhe
- Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, Netherlands
| | - Martin Beukema
- Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, Netherlands
| | - Lingmin Tian
- Laboratory of Food Chemistry, Wageningen University, Wageningen, Netherlands
| | - Berit Troost
- Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, Netherlands
| | - Jan Scholte
- Faculty of Mathematics and Natural Sciences, Neuroendocrinology, Groningen Institute for Evolutionary Life Sciences, Groningen, Netherlands
| | - Erik Bruininx
- Agrifirm Innovation Center, Apeldoorn, Netherlands
- Animal Nutrition Group, Wageningen University, Wageningen, Netherlands
| | | | | | - Anton Scheurink
- Faculty of Mathematics and Natural Sciences, Neuroendocrinology, Groningen Institute for Evolutionary Life Sciences, Groningen, Netherlands
| | - Henk A. Schols
- Laboratory of Food Chemistry, Wageningen University, Wageningen, Netherlands
| | - Marijke M. Faas
- Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, Netherlands
- Department of Obstetrics and Gynaecology, University of Groningen, University Medical Center Groningen, Groningen, Netherlands
| | - Paul de Vos
- Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University Medical Center Groningen, Groningen, Netherlands
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Zamani P, Momtazi‐Borojeni AA, Nik ME, Oskuee RK, Sahebkar A. Nanoliposomes as the adjuvant delivery systems in cancer immunotherapy. J Cell Physiol 2018; 233:5189-5199. [DOI: 10.1002/jcp.26361] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 11/29/2017] [Indexed: 01/14/2023]
Affiliation(s)
- Parvin Zamani
- BuAli Research InstituteStudent Research CommitteeDepartment of Medical BiotechnologyNanotechnology Research CenterSchool of MedicineMashhad University of Medical SciencesMashhadIran
| | - Amir Abbas Momtazi‐Borojeni
- BuAli Research InstituteStudent Research CommitteeDepartment of Medical BiotechnologyNanotechnology Research CenterSchool of MedicineMashhad University of Medical SciencesMashhadIran
| | - Maryam Ebrahimi Nik
- Student Research CommitteeFaculty of PharmacyDepartment of NanotechnologyMashhad University of Medical SciencesMashhadIran
| | - Reza Kazemi Oskuee
- Targeted Drug Delivery Research CenterMashhad University of Medical SciencesMashhadIran
| | - Amirhossein Sahebkar
- Biotechnology Research CenterPharmaceutical Technology InstituteMashhad University of Medical SciencesMashhadIran
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Interaction of Mycoplasma hominis PG21 with Human Dendritic Cells: Interleukin-23-Inducing Mycoplasmal Lipoproteins and Inflammasome Activation of the Cell. J Bacteriol 2017; 199:JB.00213-17. [PMID: 28559291 DOI: 10.1128/jb.00213-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/18/2017] [Indexed: 11/20/2022] Open
Abstract
Mycoplasma hominis lacks a cell wall, and lipoproteins anchored to the extracellular side of the plasma membrane are in direct contact with the host components. A Triton X-114 extract of M. hominis enriched with lipoproteins was shown to stimulate the production of interleukin-23 (IL-23) by human dendritic cells (hDCs). The inflammasome activation of the host cell has never been reported upon M. hominis infection. We studied here the interaction between M. hominis PG21 and hDCs by analyzing both the inflammation-inducing mycoplasmal lipoproteins and the inflammasome activation of the host cell. IL-23-inducing lipoproteins were determined using a sequential extraction strategy with two nondenaturing detergents, Sarkosyl and Triton X-114, followed by SDS-PAGE separation and mass spectrometry identification. The activation of the hDC inflammasome was assessed using PCR array and enzyme-linked immunosorbent assay (ELISA). We defined a list of 24 lipoproteins that could induce the secretion of IL-23 by hDCs, 5 with a molecular mass between 20 and 35 kDa and 19 with a molecular mass between 40 and 100 kDa. Among them, lipoprotein MHO_4720 was identified as potentially bioactive, and a synthetic lipopeptide corresponding to the N-terminal part of the lipoprotein was subsequently shown to induce IL-23 release by hDCs. Regarding the hDC innate immune response, inflammasome activation with caspase-dependent production of IL-1β was observed. After 24 h of coincubation of hDCs with M. hominis, downregulation of the NLRP3-encoding gene and of the adaptor PYCARD-encoding gene was noticed. Overall, this study provides insight into both protagonists of the interaction of M. hominis and hDCs.IMPORTANCEMycoplasma hominis is a human urogenital pathogen involved in gynecologic and opportunistic infections. M. hominis lacks a cell wall, and its membrane contains many lipoproteins that are anchored to the extracellular side of the plasma membrane. In the present study, we focused on the interaction between M. hominis and human dendritic cells and examined both sides of the interaction, the mycoplasmal lipoproteins involved in the activation of the host cell and the immune response of the cell. On the mycoplasmal side, we showed for the first time that M. hominis lipoproteins with high molecular mass were potentially bioactive. On the cell side, we reported an activation of the inflammasome, which is involved in the innate immune response.
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Wang YH, Nemati R, Anstadt E, Liu Y, Son Y, Zhu Q, Yao X, Clark RB, Rowe DW, Nichols FC. Serine dipeptide lipids of Porphyromonas gingivalis inhibit osteoblast differentiation: Relationship to Toll-like receptor 2. Bone 2015; 81:654-661. [PMID: 26409254 PMCID: PMC4641032 DOI: 10.1016/j.bone.2015.09.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 09/15/2015] [Accepted: 09/19/2015] [Indexed: 11/16/2022]
Abstract
Porphyromonas gingivalis is a periodontal pathogen strongly associated with loss of attachment and supporting bone for teeth. We have previously shown that the total lipid extract of P. gingivalis inhibits osteoblast differentiation through engagement of Toll-like receptor 2 (TLR2) and that serine dipeptide lipids of P. gingivalis engage both mouse and human TLR2. The purpose of the present investigation was to determine whether these serine lipids inhibit osteoblast differentiation in vitro and in vivo and whether TLR2 engagement is involved. Osteoblasts were obtained from calvaria of wild type or TLR2 knockout mouse pups that also express the Col2.3GFP transgene. Two classes of serine dipeptide lipids, termed Lipid 654 and Lipid 430, were tested. Osteoblast differentiation was monitored by cell GFP fluorescence and osteoblast gene expression and osteoblast function was monitored as von Kossa stained mineral deposits. Osteoblast differentiation and function were evaluated in calvarial cell cultures maintained for 21 days. Lipid 654 significantly inhibited GFP expression, osteoblast gene expression and mineral nodule formation and this inhibition was dependent on TLR2 engagement. Lipid 430 also significantly inhibited GFP expression, osteoblast gene expression and mineral nodule formation but these effects were only partially attributed to engagement of TLR2. More importantly, Lipid 430 stimulated TNF-α and RANKL gene expression in wild type cells but not in TLR2 knockout cells. Finally, osteoblast cultures were observed to hydrolyze Lipid 654 to Lipid 430 and this likely occurs through elevated PLA2 activity in the cultured cells. In conclusion, our results show that serine dipeptide lipids of P. gingivalis inhibit osteoblast differentiation and function at least in part through engagement of TLR2. The Lipid 430 serine class also increased the expression of genes that could increase osteoclast activity. We conclude that Lipid 654 and Lipid 430 have the potential to promote TLR2-dependent bone loss as is reported in experimental periodontitis following oral infection with P. gingivalis. These results also support the conclusion that serine dipeptide lipids are involved in alveolar bone loss in chronic periodontitis.
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Affiliation(s)
- Yu-Hsiung Wang
- Department of Craniofacial Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030, USA
| | - Reza Nemati
- From the Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA
| | - Emily Anstadt
- Department of Immunology and Medicine, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - Yaling Liu
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030, USA
| | - Young Son
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030, USA
| | - Qiang Zhu
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030, USA
| | - Xudong Yao
- From the Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA; Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
| | - Robert B Clark
- Department of Immunology and Medicine, University of Connecticut School of Medicine, Farmington, CT 06030, USA
| | - David W Rowe
- Department of Reconstuctive Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030, USA
| | - Frank C Nichols
- Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine, Farmington, CT 06030, USA.
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The role of TLR2, TLR4 and CD36 in macrophage activation and foam cell formation in response to oxLDL in humans. Hum Immunol 2014; 75:322-9. [DOI: 10.1016/j.humimm.2014.01.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 01/03/2014] [Accepted: 01/14/2014] [Indexed: 12/20/2022]
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Bordetella pertussis proteins dominating the major histocompatibility complex class II-presented epitope repertoire in human monocyte-derived dendritic cells. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:641-50. [PMID: 24599530 DOI: 10.1128/cvi.00665-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Knowledge of naturally processed Bordetella pertussis-specific T cell epitopes may help to increase our understanding of the basis of cell-mediated immune mechanisms to control this reemerging pathogen. Here, we elucidate for the first time the dominant major histocompatibility complex (MHC) class II-presented B. pertussis CD4(+) T cell epitopes, expressed on human monocyte-derived dendritic cells (MDDC) after the processing of whole bacterial cells by use of a platform of immunoproteomics technology. Pertussis epitopes identified in the context of HLA-DR molecules were derived from two envelope proteins, i.e., putative periplasmic protein (PPP) and putative peptidoglycan-associated lipoprotein (PAL), and from two cytosolic proteins, i.e., 10-kDa chaperonin groES protein (groES) and adenylosuccinate synthetase (ASS). No epitopes were detectable from known virulence factors. CD4(+) T cell responsiveness in healthy adults against peptide pools representing epitope regions or full proteins confirmed the immunogenicity of PAL, PPP, groES, and ASS. Elevated lymphoproliferative activity to PPP, groES, and ASS in subjects within a year after the diagnosis of symptomatic pertussis suggested immunogenic exposure to these proteins during clinical infection. The PAL-, PPP-, groES-, and ASS-specific responses were associated with secretion of functional Th1 (tumor necrosis factor alpha [TNF-α] and gamma interferon [IFN-γ]) and Th2 (interleukin 5 [IL-5] and IL-13) cytokines. Relative paucity in the natural B. pertussis epitope display of MDDC, not dominated by epitopes from known protective antigens, can interfere with the effectiveness of immune recognition of B. pertussis. A more complete understanding of hallmarks in B. pertussis-specific immunity may advance the design of novel immunological assays and prevention strategies.
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Miles B, Abdel-Ghaffar KA, Gamal AY, Baban B, Cutler CW. Blood dendritic cells: "canary in the coal mine" to predict chronic inflammatory disease? Front Microbiol 2014; 5:6. [PMID: 24478766 PMCID: PMC3902297 DOI: 10.3389/fmicb.2014.00006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/07/2014] [Indexed: 12/19/2022] Open
Abstract
The majority of risk factors for chronic inflammatory diseases are unknown. This makes personalized medicine for assessment, prognosis, and choice of therapy very difficult. It is becoming increasingly clear, however, that low-grade subclinical infections may be an underlying cause of many chronic inflammatory diseases and thus may contribute to secondary outcomes (e.g., cancer). Many diseases are now categorized as inflammatory-mediated diseases that stem from a dysregulation in host immunity. There is a growing need to study the links between low-grade infections, the immune responses they elicit, and how this impacts overall health. One such link explored in detail here is the extreme sensitivity of myeloid dendritic cells (mDCs) in peripheral blood to chronic low-grade infections and the role that these mDCs play in arbitrating the resulting immune responses. We find that emerging evidence supports a role for pathogen-induced mDCs in chronic inflammation leading to increased risk of secondary clinical disease. The mDCs that are elevated in the blood as a result of low-grade bacteremia often do not trigger a productive immune response, but can disseminate the pathogen throughout the host. This aberrant trafficking of mDCs can accelerate systemic inflammatory disease progression. Conversely, restoration of dendritic cell homeostasis may aid in pathogen elimination and minimize dissemination. Thus it would seem prudent when assessing chronic inflammatory disease risk to consider blood mDC numbers, and the microbial content (microbiome) and activation state of these mDCs. These may provide important clues (“the canary in the coal mine”) of high inflammatory disease risk. This will facilitate development of novel immunotherapies to eliminate such smoldering infections in atherosclerosis, cancer, rheumatoid arthritis, and pre-eclampsia.
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Affiliation(s)
- Brodie Miles
- Department of Periodontics, College of Dental Medicine, Georgia Regents University Augusta, GA, USA
| | | | | | - Babak Baban
- Department of Oral Biology, Georgia Regents University Augusta, GA, USA
| | - Christopher W Cutler
- Department of Periodontics, College of Dental Medicine, Georgia Regents University Augusta, GA, USA
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Kim HW, Cho SI, Bae S, Kim H, Kim Y, Hwang YI, Kang JS, Lee WJ. Vitamin C Up-regulates Expression of CD80, CD86 and MHC Class II on Dendritic Cell Line, DC-1 Via the Activation of p38 MAPK. Immune Netw 2012; 12:277-83. [PMID: 23396903 PMCID: PMC3566423 DOI: 10.4110/in.2012.12.6.277] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 12/11/2012] [Accepted: 12/14/2012] [Indexed: 01/15/2023] Open
Abstract
Vitamin C is an essential water-soluble nutrient which primarily exerts its effect on host defense mechanisms and immune homeostasis, but the mechanism related to immune-potentiation is poorly understood. Since dendritic cells (DCs) are known as a potent antigen presenting cell (APC) that could enhance the antigen specific immune responses, we investigate the effects of vitamin C on activation of DCs and its related mechanism by using dendritic cell lines, DC-1. First, we found that there was no damage on DC-1 by 2.5 mM of vitamin C. In the presence of vitamin C, the expression of CD80, CD86, and MHC molecules was increased, but it was decreased by the pre-treatment of SB203580, p38 MAPK-specific inhibitor. We confirmed the phosphorylation of p38 MAPK was increased by the treatment of vitamin C. Taken together, these results suggest that vitamin C could enhance the activity of dendritic cells via the up-regulation of the expression of CD80, CD86, and MHC molecules and the activation of p38 MAPK is related to this process.
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Affiliation(s)
- Hyung Woo Kim
- School of Korean Medicine, Pusan National University, Pusan 626-870, Korea
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Zom GGP, Khan S, Filippov DV, Ossendorp F. TLR ligand-peptide conjugate vaccines: toward clinical application. Adv Immunol 2012; 114:177-201. [PMID: 22449782 DOI: 10.1016/b978-0-12-396548-6.00007-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Approaches to treat cancer with therapeutic vaccination have made significant progress. In order to induce efficient antitumor immunity, a vaccine should target and activate antigen-presenting cells, such as the dendritic cell, while delivering the tumor-derived antigen of choice. Conjugates of synthetic peptides and ligands of pattern-recognition receptors (PRRs) combine these features and, given their synthetic nature, can be produced under GMP conditions. Therefore, conjugation of antigenic peptides to potent PRR ligands is a promising vaccination approach for the treatment of cancer. This review focuses on the different PRR families that can be exploited for the design of conjugates and explores the results obtained so far with PRR ligands conjugated to antigen. The uptake and processing of Toll-like receptor ligand-peptide conjugates are discussed in more detail, as well as future directions that may further enhance the immunogenicity of conjugates.
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Affiliation(s)
- Gijs G P Zom
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, The Netherlands
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Free lipid A isolated from Porphyromonas gingivalis lipopolysaccharide is contaminated with phosphorylated dihydroceramide lipids: recovery in diseased dental samples. Infect Immun 2011; 80:860-74. [PMID: 22144487 DOI: 10.1128/iai.06180-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Recent reports indicate that Porphyromonas gingivalis mediates alveolar bone loss or osteoclast modulation through engagement of Toll-like receptor 2 (TLR2), though the factors responsible for TLR2 engagement have yet to be determined. Lipopolysaccharide (LPS) and lipid A, lipoprotein, fimbriae, and phosphorylated dihydroceramides of P. gingivalis have been reported to activate host cell responses through engagement of TLR2. LPS and lipid A are the most controversial in this regard because conflicting evidence has been reported concerning the capacity of P. gingivalis LPS or lipid A to engage TLR2 versus TLR4. In the present study, we first prepared P. gingivalis LPS by the Tri-Reagent method and evaluated this isolate for contamination with phosphorylated dihydroceramide lipids. Next, the lipid A prepared from this LPS was evaluated for the presence of phosphorylated dihydroceramide lipids. Finally, we characterized the lipid A by the matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) and electrospray-MS methods in order to quantify recovery of lipid A in lipid extracts from diseased teeth or subgingival plaque samples. Our results demonstrate that both the LPS and lipid A derived from P. gingivalis are contaminated with phosphorylated dihydroceramide lipids. Furthermore, the lipid extracts derived from diseased teeth or subgingival plaque do not contain free lipid A constituents of P. gingivalis but contain substantial amounts of phosphorylated dihydroceramide lipids. Therefore, the free lipid A of P. gingivalis is not present in measurable levels at periodontal disease sites. Our results also suggest that the TLR2 activation of host tissues attributed to LPS and lipid A of P. gingivalis could actually be mediated by phosphorylated dihydroceramides.
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van Maren WWC, Nierkens S, Toonen LW, Bolscher JM, Sutmuller RPM, Adema GJ. Multifaceted effects of synthetic TLR2 ligand and Legionella pneumophilia on Treg-mediated suppression of T cell activation. BMC Immunol 2011; 12:23. [PMID: 21435210 PMCID: PMC3078900 DOI: 10.1186/1471-2172-12-23] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 03/24/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Regulatory T cells (Treg) play a crucial role in maintaining immune homeostasis and self-tolerance. The immune suppressive effects of Tregs should however be limited in case effective immunity is required against pathogens or cancer cells. We previously found that the Toll-like receptor 2 (TLR2) agonist, Pam3CysSK4, directly stimulated Tregs to expand and temporarily abrogate their suppressive capabilities. In this study, we evaluate the effect of Pam3CysSK4 and Legionella pneumophila, a natural TLR2 containing infectious agent, on effector T (Teff) cells and dendritic cells (DCs) individually and in co-cultures with Tregs. RESULTS TLR2 agonists can directly provide a co-stimulatory signal inducing enhanced proliferation and cytokine production of naive CD4+ Teff cells. With respect to cytokine production, DCs appear to be most sensitive to low amounts of TLR agonists. Using wild type and TLR2-deficient cells in Treg suppression assays, we accordingly show that all cells (e.g. Treg, Teff cells and DCs) contributed to overcome Treg-mediated suppression of Teff cell proliferation. Furthermore, while TLR2-stimulated Tregs readily lost their ability to suppress Teff cell proliferation, cytokine production by Teff cells was still suppressed. Similar results were obtained upon stimulation with TLR2 ligand containing bacteria, Legionella pneumophila. CONCLUSIONS These findings indicate that both synthetic and natural TLR2 agonists affect DCs, Teff cells and Treg directly, resulting in multi-modal modulation of Treg-mediated suppression of Teff cells. Moreover, Treg-mediated suppression of Teff cell proliferation is functionally distinct from suppression of cytokine secretion.
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Affiliation(s)
- Wendy WC van Maren
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Stefan Nierkens
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Liza W Toonen
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Judith M Bolscher
- Schering-Plough Research Institute, Target Discovery Oss, Molenstraat 110, 5340 BH Oss, The Netherlands
| | - Roger PM Sutmuller
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
- Schering-Plough Research Institute, Target Discovery Oss, Molenstraat 110, 5340 BH Oss, The Netherlands
| | - Gosse J Adema
- Department of Tumor Immunology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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Huang CB, Alimova YV, Strange S, Ebersole JL. Polybacterial challenge enhances HIV reactivation in latently infected macrophages and dendritic cells. Immunology 2010; 132:401-9. [PMID: 21073452 DOI: 10.1111/j.1365-2567.2010.03375.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A polymicrobial infection comprising subgingival biofilms is the trigger for the chronic immunoinflammatory lesions of periodontitis. These microbial biofilms interface with host immune cells that increase with progressing disease and could result in HIV reactivation in HIV-1-infected patients. Previous reports have focused on the ability of monospecies challenge of macrophages and dendritic cells to detail molecular aspects of their detection and signalling pathways. This study provides a seminal description of the responses of macrophages and dendritic cells to a polybacterial challenge using various oral bacteria as prototype stimuli to examine these response characteristics. The investigation employed a model of HIV-promoter activation and reactivation of HIV viral replication. Oral Gram-negative bacteria elicited significantly greater levels of HIV promoter activation and viral replication from all cell types, compared with Gram-positive bacteria. Selected combinations of oral Gram-negative bacteria elicited synergistic HIV promoter activation and viral replication in macrophages and immature dendritic cells. In mature dendritic cells, there was no synergism in HIV promoter activation and viral replication. Gram-positive bacteria showed no synergism in any cell model. These findings support the importance of determining the characteristics and impact of polybacterial challenges on immune cells to clarify the potential immune recognition and antigen processing that can occur in the oral cavity.
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Affiliation(s)
- Chifu B Huang
- Center for Oral Health Research, College of Dentistry, University of Kentucky, Lexington, KY 40536, USA.
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Porphyromonas gingivalis lipids inhibit osteoblastic differentiation and function. Infect Immun 2010; 78:3726-35. [PMID: 20584977 DOI: 10.1128/iai.00225-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Porphyromonas gingivalis produces unusual sphingolipids that are known to promote inflammatory reactions in gingival fibroblasts and Toll-like receptor 2 (TLR2)-dependent secretion of interleukin-6 from dendritic cells. The aim of the present study was to examine whether P. gingivalis lipids inhibit osteoblastic function. Total lipids from P. gingivalis and two fractions, phosphoglycerol dihydroceramides and phosphoethanolamine dihydroceramides, were prepared free of lipid A. Primary calvarial osteoblast cultures derived from 5- to 7-day-old CD-1 mice were used to examine the effects of P. gingivalis lipids on mineralized nodule formation, cell viability, apoptosis, cell proliferation, and gene expression. P. gingivalis lipids inhibited osteoblast differentiation and fluorescence expression of pOBCol2.3GFP in a concentration-dependent manner. However, P. gingivalis lipids did not significantly alter osteoblast proliferation, viability, or apoptosis. When administered during specific intervals of osteoblast growth, P. gingivalis total lipids demonstrated inhibitory effects on osteoblast differentiation only after the proliferation stage of culture. Reverse transcription-PCR confirmed the downregulation of osteoblast marker genes, including Runx2, ALP, OC, BSP, OPG, and DMP-1, with concurrent upregulation of RANKL, tumor necrosis factor alpha, and MMP-3 genes. P. gingivalis total lipids and lipid fractions inhibited calvarial osteoblast gene expression and function in vivo, as determined by the loss of expression of another osteoblast differentiation reporter, pOBCol3.6GFPcyan, and reduced uptake of Alizarin complexone stain. Finally, lipid inhibition of mineral nodule formation in vitro was dependent on TLR2 expression. Our results indicate that inhibition of osteoblast function and gene expression by P. gingivalis lipids represents a novel mechanism for altering alveolar bone homeostasis at periodontal disease sites.
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Signaling mechanisms involved in altered function of macrophages from diet-induced obese mice affect immune responses. Proc Natl Acad Sci U S A 2009; 106:10740-5. [PMID: 19541650 DOI: 10.1073/pnas.0904412106] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Recent research links diet-induced obesity (DIO) with impaired immunity, although the underlying mechanisms remain unclear. We find that the induction of inducible NO synthase (iNOS) and cytokines is suppressed in mice with DIO and in bone marrow macrophages (BMMPhi) from mice with DIO exposed to an oral pathogen, Porphyromonas gingivalis. BMMPhi from lean mice pre-treated with free fatty acids (FFAs) and exposed to P. gingivalis also exhibit a diminished induction of iNOS and cytokines. BMMPhi from lean and obese mice exposed to P. gingivalis and analyzed by a phosphorylation protein array show a reduction of Akt only in BMMPhi from mice with DIO. This reduction is responsible for diminished NF-kappaB activation and diminished induction of iNOS and cytokines. We next observed that Toll-like receptor 2 (TLR2) is suppressed in BMMPhi from DIO mice whereas carboxy-terminal modulator protein (CTMP), a known suppressor of Akt phosphorylation, is elevated. This elevation stems from defective TLR2 signaling. In BMMPhi from lean mice, both FFAs and TNF-alpha--via separate pathways--induce an increase in CMTP. However, in BMMPhi from DIO mice, TLR2 can no longer inhibit the TNF-alpha-induced increase in CTMP caused by P. gingivalis challenge. This defect can then be restored by transfecting WT TLR2 into BMMPhi from DIO mice. Thus, feeding mice a high-fat diet over time elevates the CTMP intracellular pool, initially via FFAs activating TLR2 and later when the defective TLR2 is unable to inhibit TNF-alpha-induced CTMP. These findings unveil a link between obesity and innate immunity.
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Khan S, Weterings JJ, Britten CM, de Jong AR, Graafland D, Melief CJM, van der Burg SH, van der Marel G, Overkleeft HS, Filippov DV, Ossendorp F. Chirality of TLR-2 ligand Pam3CysSK4 in fully synthetic peptide conjugates critically influences the induction of specific CD8+ T-cells. Mol Immunol 2008; 46:1084-91. [PMID: 19027958 DOI: 10.1016/j.molimm.2008.10.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 09/24/2008] [Accepted: 10/08/2008] [Indexed: 02/06/2023]
Abstract
Covalent conjugation of synthetic Toll-like receptor ligands (TLR-L) to synthetic antigenic peptides provides well-defined constructs that have significantly improved capacity to induce efficient priming of CD8(+) T lymphocytes in vivo. We have recently explored the cellular mechanisms underlying the efficient induction of a CD8(+) cytotoxic T lymphocyte response by such synthetic model vaccines [Khan, S., Bijker, M.S., Weterings, J.J., Tanke, H.J., Adema, G.J., van, H.T., Drijfhout, J.W., Melief, C.J., Overkleeft, H.S., van der Marel, G.A., Filippov, D.V., van der Burg, S.H., Ossendorp, F., 2007. Distinct uptake mechanisms but similar intracellular processing of two different toll-like receptor ligand-peptide conjugates in dendritic cells. J. Biol. Chem. 282, 21145-21159.]. In the current study we have investigated the behaviour of two diastereomers of the TLR-2 ligand Pam(3)CSK(4) (Pam) derivatives, namely the R- and S-epimers at C-2 of the glycerol moiety. Other studies have shown that the Pam(3)Cys based lipopeptides of R-configuration (Pam(R)) in the glycerol moiety enhanced macrophage and B-cell activation compared to those with S-configuration (Pam(S)). Here we report that Pam(R)-conjugates lead to better activation of dendritic cells than the Pam(S)-conjugates as judged by higher IL-12 secretion, upregulation of relevant markers for dendritic cell maturation. In contrast both epimers were internalized equally efficient in a clathrin-dependent manner indicating no qualitative difference in the uptake of the two stereoisomeric Pam-conjugates. We conclude that the enhanced DC activation is due to enhanced TLR-2 triggering by the Pam(R)-conjugate in contrast to the Pam(S)-conjugate. Importantly, induction of specific CD8(+) T-cells was significantly higher in mice injected with the Pam(R)-conjugates compared to mice injected with the Pam(S)-conjugate. In summary we show that the favourable effects of the Pam(R)-configuration of TLR-2 ligand can be attributed to direct effects on dendritic cells resulting in enhancement of CD8(+) T-cell responses.
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Affiliation(s)
- Selina Khan
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands.
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Uehara A, Imamura T, Potempa J, Travis J, Takada H. Gingipains from Porphyromonas gingivalis synergistically induce the production of proinflammatory cytokines through protease-activated receptors with Toll-like receptor and NOD1/2 ligands in human monocytic cells. Cell Microbiol 2008; 10:1181-9. [PMID: 18182086 DOI: 10.1111/j.1462-5822.2008.01119.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Gingipains (HRgpA, RgpB and Kgp) are cysteine proteinases and virulence factors of Porphyromonas gingivalis, the major causative bacterium of periodontal disease. To study synergistic effects of gingipains and signalling via Toll-like receptors (TLRs) and NOD1/2, we investigated effects of a gingipain on the secretion of proinflammatory cytokines from monocytic THP-1 cells in the presence of pathogen-associated molecular patterns (PAMPs). Gingipains stimulated interleukin (IL)-8's secretion from THP-1 cells, which was completely inhibited by proteinase inhibitors of gingipain and increased in the presence of PAMPs. Synergistic effects of gingipains and PAMPs were also seen in the secretion of IL-6 and MCP-1 and reduced to about 50% the secretion of IL-8 from THP-1 cells treated with siRNA targeting either protease-activated receptor (PAR)-1, -2 or -3. PAR agonist peptides mimicked the synergistic effects of gingipains with PAMPs. These results indicate that gingipains stimulate the secretion of cytokines from monocytic cells through the activation of PARs with synergistic effects by PAMPs. This is the first report of synergism of signalling via PARs, and TLRs or NOD1/2. The host defence system against P. gingivalis may be triggered through the activation of PARs by gingipains and augmented by PAMPs from this pathogen via TLRs or NOD1/2.
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Affiliation(s)
- A Uehara
- Department of Microbiology and Immunology, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan.
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