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Garimella MG, He C, Chen G, Li QZ, Huang X, Karlsson MCI. The B cell response to both protein and nucleic acid antigens displayed on apoptotic cells are dependent on endosomal pattern recognition receptors. J Autoimmun 2020; 117:102582. [PMID: 33296829 DOI: 10.1016/j.jaut.2020.102582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/19/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022]
Abstract
In systemic autoimmune diseases such as systemic lupus erythematosus (SLE), B cell tolerance is lost and there is a production of autoantibodies that drive pathology. The specificities of these antibodies are towards a wide range of autoantigens including proteins such as serum factors including cytokines as well as towards nucleic acids and modified glycolipids. It is known that endosomal pattern recognition receptors are involved in specific responses but if they drive specificity towards a specific group of autoantigens is not known. Here, we used syngeneic apoptotic cells alone to break B cell tolerance and investigated the antibody response in Unc93b1 mutant mice that lack signalling from the TLR3, TLR7 and TLR9 receptors. We found that specific B cell responses known from patients with SLE including antibodies towards Ro-52/60, La, cardiolipin as well as DNA were all significantly lower in the knockout mice. Thus, we found that endosomal TLR receptors were involved in break of tolerance and drive B cell responses for protein, nucleic acid and modified lipid antigens. This pinpoints these receptors as key drivers for the full range of antibody driven pathology in SLE and suggests that targeting of endosomal TLR driven responses will quench all B cell driven autoreactivity.
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Affiliation(s)
- Manasa G Garimella
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet Biomedicum, Stockholm, 17165, Sweden
| | - Chenfei He
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet Biomedicum, Stockholm, 17165, Sweden
| | - Guangchun Chen
- Microarray Core, Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Quan-Zhen Li
- Microarray Core, Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xin Huang
- Department of Dermatology, Hunan Key Laboratory of Medical Epigenomics, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mikael C I Karlsson
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet Biomedicum, Stockholm, 17165, Sweden.
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Cho JA, Kim TJ, Moon HJ, Kim YJ, Yoon HK, Seong SY. Cardiolipin activates antigen-presenting cells via TLR2-PI3K-PKN1-AKT/p38-NF-kB signaling to prime antigen-specific naïve T cells in mice. Eur J Immunol 2018; 48:777-790. [PMID: 29313959 DOI: 10.1002/eji.201747222] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 12/12/2017] [Accepted: 01/02/2018] [Indexed: 12/21/2022]
Abstract
Mitochondrial defects and antimitochondrial cardiolipin (CL) antibodies are frequently detected in autoimmune disease patients. CL from dysregulated mitochondria activates various pattern recognition receptors, such as NLRP3. However, the mechanism by which mitochondrial CL activates APCs as a damage-associated molecular pattern to prime antigen-specific naïve T cells, which is crucial for T-cell-dependent anticardiolipin IgG antibody production in autoimmune diseases is unelucidated. Here, we show that CL increases the expression of costimulatory molecules in CD11c+ APCs both in vitro and in vivo. CL activates CD11c+ APCs via TLR2-PI3K-PKN1-AKT/p38MAPK-NF-κB signaling. CD11c+ APCs that have been activated by CL are sufficient to prime H-Y peptide-specific naïve CD4+ T cells and OVA-specific naïve CD8+ T cells. TLR2 is necessary for anti-CL IgG antibody responses in vivo. Intraperitoneal injection of CL does not activate CD11c+ APCs in CD14 KO mice to the same extent as in wild-type mice. CL binds to CD14 (Kd = 7 × 10-7 M). CD14, but not MD2, plays a role in NF-kB activation by CL, suggesting that CD14+ macrophages contribute to recognizing CL. In summary, CL activates signaling pathways in CD11c+ APCs through a mechanism similar to gram (+) bacteria and plays a crucial role in priming antigen-specific naïve T cells.
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Affiliation(s)
- Jung-Ah Cho
- Departments of Microbiology and Immunology, Department of Biomedical Sciences, and Wide River Institute of Immunology, Seoul National University College of Medicine, Jongno-gu, Seoul, Republic of Korea
| | - Tae-Joo Kim
- Departments of Microbiology and Immunology, Department of Biomedical Sciences, and Wide River Institute of Immunology, Seoul National University College of Medicine, Jongno-gu, Seoul, Republic of Korea
| | - Hye-Jung Moon
- Departments of Microbiology and Immunology, Department of Biomedical Sciences, and Wide River Institute of Immunology, Seoul National University College of Medicine, Jongno-gu, Seoul, Republic of Korea
| | - Young-Joo Kim
- Departments of Microbiology and Immunology, Department of Biomedical Sciences, and Wide River Institute of Immunology, Seoul National University College of Medicine, Jongno-gu, Seoul, Republic of Korea
| | - Hye-Kyung Yoon
- Departments of Microbiology and Immunology, Department of Biomedical Sciences, and Wide River Institute of Immunology, Seoul National University College of Medicine, Jongno-gu, Seoul, Republic of Korea
| | - Seung-Yong Seong
- Departments of Microbiology and Immunology, Department of Biomedical Sciences, and Wide River Institute of Immunology, Seoul National University College of Medicine, Jongno-gu, Seoul, Republic of Korea
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3
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Manthey H, Zernecke A. Dendritic cells in atherosclerosis: Functions in immune regulation and beyond. Thromb Haemost 2017; 106:772-8. [DOI: 10.1160/th11-05-0296] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 08/02/2011] [Indexed: 12/15/2022]
Abstract
SummaryChronic inflammation drives the development of atherosclerosis. Dendritic cells (DCs) are known as central mediators of adaptive immune responses and the development of immunological memory and tolerance. DCs are present in non-diseased arteries, and accumulate within atherosclerotic lesions where they can be localised in close vicinity to T cells. Recent work has revealed important functions of DCs in regulating immune mechanisms in atherogenesis, and vaccination strategies using DCs have been explored for treatment of disease. However, in line with a phenotypical and functional overlap with plaque macrophages vascular DCs were also identified to engulf lipids, thus contributing to lipid burden in the vessel wall and initiation of lesion growth. Furthermore, a function of DCs in regulating cholesterol homeostasis has been revealed. Finally, phenotypically distinct plasmacytoid dendritic cells (pDCs) have been identified within atherosclerotic lesions. This review will dissect the multifaceted contribution of DCs and pDCs to the initiation and progression of atherosclerosis and the experimental approaches utilising DCs in therapeutic vaccination strategies.
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Abstract
Systemic lupus erythematosus (SLE) is a systemic non-organ specific autoimmune disease associated with multiple autoantibodies targeting autoantigens from the nucleus. Given the complex pathophysiology of SLE and the role of TNF alpha in that disease, modulation of TNF alpha (in SLE or non-SLE patients) using TNF blockers could either be detrimental or beneficial in some patients. In this review we will focus on lupus autoantibodies and clinical manifestations after TNF blockade in SLE patients and conversely on drug-induced-SLE in non-SLE patients. Some hypotheses regarding the mechanism of induction of autoantibodies in RA patients treated with TNF blockers are proposed.
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Affiliation(s)
- M De Bandt
- Rheumatology Department, Hôpital Robert Ballanger, Aulnay sous Bois, France.
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5
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Abstract
Inflammatory and ischemic cardiovascular diseases, especially atherosclerosis and myocardial infarction, remain the number one cause of death in the Western world, whereas the therapeutic options currently available are still limited. Several recent findings have indicated that nucleic acids, particularly extracellular ribosomal RNA and micro-RNAs, significantly contribute to the adverse outcome of atherosclerosis, myocardial infarction, and other cardiovascular diseases. Extracellular RNAs act as novel danger-associated molecular pattern signals and potent cofactors in cardiovascular inflammation and thrombosis, particularly when accumulating in the extracellular space under tissue-damaging or pathological conditions. In this concise review article, the different entities of extracellular RNAs, their cellular sources, and their putative functional contribution to the pathogenesis of cardiovascular diseases will be discussed. In fact, it remains a tightrope walk for these polyanionic molecules outside cells to promote defense reactions on the one side but to provoke cardiovascular disease development on the other side, dependent on their concentration, the environmental conditions, and the cellular stimuli engaged. Thus, we will discuss the mechanisms and cellular responses by which extracellular RNAs operate between defense and disease. Finally, natural counteracting molecules, such as RNase1, will be focused on to elaborate their protective functions in the context of inflammatory and ischemic cardiovascular diseases with the possibility to apply them as novel interventional strategies.
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Affiliation(s)
- Alma Zernecke
- From the Institute of Experimental Biomedicine, University Hospital Würzburg, Würzburg, Germany (A.Z.); and Department of Biochemistry, Medical School, Justus-Liebig-University, Giessen, Germany (K.T.P.).
| | - Klaus T Preissner
- From the Institute of Experimental Biomedicine, University Hospital Würzburg, Würzburg, Germany (A.Z.); and Department of Biochemistry, Medical School, Justus-Liebig-University, Giessen, Germany (K.T.P.).
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6
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Rai V, Rao VH, Shao Z, Agrawal DK. Dendritic Cells Expressing Triggering Receptor Expressed on Myeloid Cells-1 Correlate with Plaque Stability in Symptomatic and Asymptomatic Patients with Carotid Stenosis. PLoS One 2016; 11:e0154802. [PMID: 27148736 PMCID: PMC4858252 DOI: 10.1371/journal.pone.0154802] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 04/19/2016] [Indexed: 12/22/2022] Open
Abstract
Atherosclerosis is a chronic inflammatory disease with atherosclerotic plaques containing inflammatory cells, including T-lymphocytes, dendritic cells (DCs) and macrophages that are responsible for progression and destabilization of atherosclerotic plaques. Stressed cells undergoing necrosis release molecules that act as endogenous danger signals to alert and activate innate immune cells. In atherosclerotic tissue the number of DCs increases with the progression of the lesion and produce several inflammatory cytokines and growth factors. Triggering receptor expressed on myeloid cells (TREM)-1 plays a crucial role in inflammation. However, relationship of DCs and the role of TREM-1 with the stability of atherosclerotic plaques have not been examined. In this study, we investigated the heterogeneity of the plaque DCs, myeloid (mDC1 and mDC2) and plasmacytoid (pDCs), and examined the expression of TREM-1 and their co-localization with DCs in the plaques from symptomatic (S) and asymptomatic (AS) patients with carotid stenosis. We found increased expression of HLA-DR, fascin, and TREM-1 and decreased expression of TREM-2 and α-smooth muscle actin in S compared to AS atherosclerotic carotid plaques. Both TREM-1 and fascin were co-localized suggesting increased expression of TREM-1 in plaque DCs of S compared to AS patients. These data were supported by increased mRNA transcripts of TREM-1 and decreased mRNA transcripts of TREM-2 in carotid plaques of S compared to AS patients. There was higher density of both CD1c+ mDC1 and CD141+ mDC2 in the carotid plaques from AS compared to S patients, where as the density of CD303+ pDCs were higher in the carotid plaques of S compared to AS patients. These findings suggest a potential role of pDCs and TREM-1 in atherosclerotic plaque vulnerability. Thus, newer therapies could be developed to selectively block TREM-1 for stabilizing atherosclerotic plaques.
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Affiliation(s)
- Vikrant Rai
- Department of Clinical and Translational Science, Creighton University School of Medicine, Omaha, Nebraska 68178, United States of America
| | - Velidi H. Rao
- Department of Clinical and Translational Science, Creighton University School of Medicine, Omaha, Nebraska 68178, United States of America
| | - Zhifei Shao
- Department of Clinical and Translational Science, Creighton University School of Medicine, Omaha, Nebraska 68178, United States of America
| | - Devendra K. Agrawal
- Department of Clinical and Translational Science, Creighton University School of Medicine, Omaha, Nebraska 68178, United States of America
- * E-mail:
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7
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Zernecke A. Distinct functions of specialized dendritic cell subsets in atherosclerosis and the road ahead. SCIENTIFICA 2014; 2014:952625. [PMID: 24818041 PMCID: PMC4003768 DOI: 10.1155/2014/952625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 03/20/2014] [Indexed: 06/03/2023]
Abstract
Atherosclerotic vascular disease is modulated by immune mechanisms. Dendritic cells (DCs) and T cells are present within atherosclerotic lesions and function as central players in the initiation and modulation of adaptive immune responses. In previous years, we have studied the functional contribution of distinct DC subsets in disease development, namely, that of CCL17-expressing DCs as well as that of plasmacytoid DCs that play specialized roles in disease development. This review focuses on important findings gathered in these studies and dissects the multifaceted contribution of CCL17-expressing DCs and pDCs to the pathogenesis of atherosclerosis. Furthermore, an outlook on future challenges faced when studying DCs in this detrimental disease are provided, and hurdles that will need to be overcome in order to enable a better understanding of the contribution of DCs to atherogenesis are discussed, a prerequisite for their therapeutic targeting in atherosclerosis.
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Affiliation(s)
- Alma Zernecke
- Institute of Clinical Biochemistry and Pathobiochemistry, University Hospital Würzburg, Josef-Schneider-Straße 2, 97080 Würzburg, Germany
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Döring Y, Manthey HD, Drechsler M, Lievens D, Megens RTA, Soehnlein O, Busch M, Manca M, Koenen RR, Pelisek J, Daemen MJ, Lutgens E, Zenke M, Binder CJ, Weber C, Zernecke A. Auto-antigenic protein-DNA complexes stimulate plasmacytoid dendritic cells to promote atherosclerosis. Circulation 2012; 125:1673-83. [PMID: 22388324 DOI: 10.1161/circulationaha.111.046755] [Citation(s) in RCA: 301] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Inflammation has been closely linked to auto-immunogenic processes in atherosclerosis. Plasmacytoid dendritic cells (pDCs) are specialized to produce type-I interferons in response to pathogenic single-stranded nucleic acids, but can also sense self-DNA released from dying cells or in neutrophil extracellular traps complexed to the antimicrobial peptide Cramp/LL37 in autoimmune disease. However, the exact role of pDCs in atherosclerosis remains elusive. METHODS AND RESULTS Here we demonstrate that pDCs can be detected in murine and human atherosclerotic lesions. Exposure to oxidatively modified low-density lipoprotein enhanced the capacity of pDCs to phagocytose and prime antigen-specific T cell responses. Plasmacytoid DCs can be stimulated to produce interferon-α by Cramp/DNA complexes, and we further identified increased expression of Cramp and formation of neutrophil extracellular traps in atherosclerotic arteries. Whereas Cramp/DNA complexes aggravated atherosclerotic lesion formation in apolipoprotein E-deficient mice, pDC depletion and Cramp-deficiency in bone marrow reduced atherosclerosis and anti-double-stranded DNA antibody titers. Moreover, the specific activation of pDCs and interferon-α treatment promoted plaque growth, associated with enhanced anti-double-stranded-DNA antibody titers. Accordingly, anti-double-stranded DNA antibodies were elevated in patients with symptomatic versus asymptomatic carotid artery stenosis. CONCLUSIONS Self-DNA (eg, released from dying cells or in neutrophil extracellular traps) and an increased expression of the antimicrobial peptide Cramp/LL37 in atherosclerotic lesions may thus stimulate a pDC-driven pathway of autoimmune activation and the generation of anti-double-stranded-DNA antibodies, critically aggravating atherosclerosis lesion formation. These key factors may thus represent novel therapeutic targets.
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Affiliation(s)
- Yvonne Döring
- Rudolf Virchow Center, DFG Research Center for Experimental Medicine, University of Würzburg, Josef-Schneider Strasse 2, Würzburg, Germany
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9
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York MR. Novel insights on the role of the innate immune system in systemic sclerosis. Expert Rev Clin Immunol 2011; 7:481-9. [PMID: 21790291 DOI: 10.1586/eci.11.40] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Over the last several years the involvement of the innate immune system in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus (SLE) has become well established. As systemic sclerosis (SSc; scleroderma) shares clinical features and autoantibodies with SLE, investigation has recently focused on the role of innate immunity in SSc. This has been supported by recent genetic studies. However, unlike SLE and other related autoimmune diseases, SSc patients suffer from pathologic fibrosis of skin and internal organs. The fibrotic component of SSc shares several features with syndromes following environmental exposures to agents such as organic solvents, silica dust and bleomycin. Recent work in SSc and these related fibrotic diseases have identified several areas in which innate immunity can stimulate inflammation as well as fibrosis. This article will focus on the recent discoveries identifying a prominent role of cells of the innate immune system, pattern recognition receptors, and activation of dendritic cells in the pathogenesis of SSc.
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Affiliation(s)
- Michael R York
- Section of Rheumatology, Boston University Medical Campus, 72 East Concord St, Evans 501, Boston, MA 02118, USA.
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10
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Th17 (IFNγ- IL17+) CD4+ T cells generated after burn injury may be a novel cellular mechanism for postburn immunosuppression. ACTA ACUST UNITED AC 2011; 70:681-90. [PMID: 21610359 DOI: 10.1097/ta.0b013e31820d18a6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND The mechanism responsible for initiating and controlling the immunosuppressive response after burn injury remains unknown. Interleukin-17 (IL-17) secreting Th17 (interferon [IFN]γ IL17) cells are a novel subset of CD4 T cells associated with a weak, proinflammatory response that antagonizes the proinflammatory Th1 (IFNγ IL17) response. Given that transforming growth factor-β and IL6 mediate Th17 cell development, we hypothesized that burn injury may generate Th17 cells that could mediate postburn immunosuppression. METHODS After a 20% total body surface area burn in female C57BL/6 mice, wound-draining lymph nodes were harvested 3 days, 7 days, or 14 days after injury. CD4 T cells were enriched by magnetic selection, and flow cytometry was used to identify intracellular IL17 and IFNγ in CD3CD4 T cells. Additional purified CD3CD4 T cells were cultured with Th17 polarizing IL6 and transforming growth factor-β for 4 days, and flow cytometry was again used to identify intracellular IL17 and IFNγ in CD4 T cells. RESULTS The number and percentage of preformed Th17 cells was significantly greater in burn mice compared with sham at all time points. In addition, the ratio of Th17 cells to Th1 cells was always significantly higher in burn mice compared with sham. These differences were eliminated in Th17 polarizing conditions in vitro. CD4 T cells never generated both IL17 and IFNγ. CONCLUSION These results demonstrate for the first time that Th17 cells (IFNγ IL17) are spontaneously generated after burn injury. Given that Th17 cells (IFNγ IL17) are antagonistic to Th1 (IFNγ IL17) cells, these results suggest a novel mechanism for initiating and controlling postburn immunosuppression that deserves further investigation.
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Niessner A, Shin MS, Pryshchep O, Goronzy JJ, Chaikof EL, Weyand CM. Synergistic proinflammatory effects of the antiviral cytokine interferon-alpha and Toll-like receptor 4 ligands in the atherosclerotic plaque. Circulation 2007; 116:2043-52. [PMID: 17938289 DOI: 10.1161/circulationaha.107.697789] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Interferon (IFN)-alpha is a pluripotent inflammatory cytokine typically induced by viral infections. In rupture-prone atherosclerotic plaques, plasmacytoid dendritic cells produce IFN-alpha. In the present study we explored the contribution of IFN-alpha to inflammation and tissue injury in the plaque microenvironment. METHODS AND RESULTS In 53% of carotid plaques (n=30), CD123+ plasmacytoid dendritic cells clustered together with CD11c+ myeloid dendritic cells, a distinct dendritic cell subset specialized in sensing danger signals from bacteria and tissue breakdown. Tissue concentrations of IFN-alpha and tumor necrosis factor (TNF)-alpha transcripts were tightly correlated (r=0.76, P<0.001), suggesting a regulatory role of IFN-alpha in TNF-alpha production. Plaque tissue stimulation with CpG ODN, a Toll-like receptor (TLR) 9 ligand, increased IFN-alpha production (57.8+/-23.7 versus 25.9+/-8.6 pg/mL; P<0.001), whereas the TLR4 ligand lipopolysaccharide induced TNF-alpha secretion (225.1+/-3.0 versus 0.7+/-0.2 pg/mL; P<0.001). Treating plaque tissue with IFN-alpha markedly enhanced lipopolysaccharide-triggered TNF-alpha secretion (559.0+/-25.9 versus 225.1+/-3.0 pg/mL; P<0.001). IFN-alpha pretreatment also amplified the effects of lipopolysaccharide on interleukin-12, interleukin-23, and matrix metalloproteinase-9, suggesting that the antiviral cytokine sensitized myeloid dendritic cells and macrophages toward TLR4 ligands. Mechanistic studies demonstrated that IFN-alpha modulated the myeloid dendritic cell response pattern by upregulating TLR4 expression (P<0.001) involving both the STAT (signal transducer and activator of transcription) and the PI(3)K pathway. CONCLUSIONS In the atherosclerotic plaque, IFN-alpha functions as an inflammatory amplifier. It sensitizes antigen-presenting cells toward pathogen-derived TLR4 ligands by upregulating TLR4 expression and intensifies TNF-alpha, interleukin-12, and matrix metalloproteinase-9 production, all implicated in plaque destabilization. Thus, IFN-alpha-inducing pathogens, even when colonizing distant tissue sites, threaten the stability of inflamed atherosclerotic plaque.
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Affiliation(s)
- Alexander Niessner
- Kathleen B. and Mason I. Lowance Center for Human Immunology, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
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12
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York MR, Nagai T, Mangini AJ, Lemaire R, van Seventer JM, Lafyatis R. A macrophage marker, Siglec-1, is increased on circulating monocytes in patients with systemic sclerosis and induced by type I interferons and toll-like receptor agonists. ACTA ACUST UNITED AC 2007; 56:1010-20. [PMID: 17328080 DOI: 10.1002/art.22382] [Citation(s) in RCA: 225] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Microarray analyses of peripheral blood leukocytes have shown that patients with systemic lupus erythematosus express increased levels of type I interferon (IFN)-regulated genes. In this study we examined gene expression by peripheral blood mononuclear cells (PBMCs) from patients with systemic sclerosis (SSc) to better understand the dysregulation of the immune system in this disease. METHODS PBMC gene expression was analyzed by microarray and confirmed by real-time polymerase chain reaction (PCR). Surface protein expression of Siglec-1 was analyzed by flow cytometry in PBMCs from healthy control subjects and patients with SSc, and in control PBMCs that were cultured in vitro with Toll-like receptor (TLR) agonists. RESULTS SSc patients showed increased expression of a cluster of IFN-regulated genes, including Siglec-1 (CD169, sialoadhesin). This result was verified and extended by real-time PCR, showing that a subset of the SSc patients expressed strikingly increased levels of Siglec-1 messenger RNA (mRNA). Flow cytometry of PBMCs from SSc patients and healthy controls showed increased Siglec-1 surface protein expression, which was restricted to CD14+ monocytes. In vitro studies showed that type I IFN and certain TLR agonists, including TLR-7 and TLR-9, induced Siglec-1 mRNA and protein expression. Moreover, TLR induction of surface Siglec-1 was shown to be type I IFN-dependent. Increased numbers of Siglec-1+ cells were observed by immunohistochemistry in the skin of SSc patients compared with healthy controls. CONCLUSION Increased expression of Siglec-1 in circulating SSc monocytes and tissue macrophages suggests that type I IFN-mediated activation of monocytes occurs in SSc, possibly through TLR activation of IFN secretion. These observations indicate a potential role for type I IFN-activated monocyte/macrophages in the pathogenesis of SSc.
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Affiliation(s)
- Michael R York
- Boston University Medical Center, Boston, Massachusetts 02118, USA
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FitzGerald O, McInnes I. Spondyloarthropathy: disease at the crossroads of immunity. Best Pract Res Clin Rheumatol 2006; 20:949-67. [PMID: 16980217 DOI: 10.1016/j.berh.2006.06.010] [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] [Indexed: 12/15/2022]
Abstract
Up until recently, the prevailing paradigm relating to spondyloarthropathy (SpA) pathogenesis was that they were human leukocyte antigen (HLA)-associated, T-cell-driven autoimmune diseases. This view is now being questioned. Careful studies of well-characterised cohorts of patients with SpA, including detailed analysis of involved tissue, together with clinical trials of targeted treatments, in particular anti-tumour necrosis factor (TNF) therapies, have contributed enormously to both interest in and understanding of disease pathogenesis. In this chapter, our current knowledge and understanding of the relative contributions of the components of the innate and adaptive arms of the immune response to SpA pathogenesis is reviewed. It is clear that both arms of the immune response are involved and inter-dependent in SpA. With continued emphasis on discovery research, including detailed analysis of novel therapeutic interventions, significant additional breakthroughs in SpA are likely to be forthcoming.
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Subramanian S, Tus K, Li QZ, Wang A, Tian XH, Zhou J, Liang C, Bartov G, McDaniel LD, Zhou XJ, Schultz RA, Wakeland EK. A Tlr7 translocation accelerates systemic autoimmunity in murine lupus. Proc Natl Acad Sci U S A 2006; 103:9970-5. [PMID: 16777955 PMCID: PMC1502563 DOI: 10.1073/pnas.0603912103] [Citation(s) in RCA: 485] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The y-linked autoimmune accelerating (yaa) locus is a potent autoimmune disease allele. Transcription profiling of yaa-bearing B cells revealed the overexpression of a cluster of X-linked genes that included Tlr7. FISH analysis demonstrated the translocation of this segment onto the yaa chromosome. The resulting overexpression of Tlr7 increased in vitro responses to Toll-like receptor (TLR) 7 signaling in all yaa-bearing males. B6.yaa mice are not overtly autoimmune, but the addition of Sle1, which contains the autoimmune-predisposing Slam/Cd2 haplotype, causes the development of fatal lupus with numerous immunological aberrations. B6.Sle1yaa CD4 T cells develop the molecular signature for T(FH) cells and also show expression changes in numerous cytokines and chemokines. Disease development and all component autoimmune phenotypes were inhibited by Sles1, a potent suppressor locus. Sles1 had no effect on yaa-enhanced TLR7 signaling in vitro, and these data place Sles1 downstream from the lesion in innate immune responses mediated by TLR7, suggesting that Sles1 modulates the activation of adaptive immunity in response to innate immune signaling.
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Affiliation(s)
| | | | | | | | | | | | | | - Guy Bartov
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - Lisa D. McDaniel
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - Xin J. Zhou
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - Roger A. Schultz
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - Edward K. Wakeland
- *Center for Immunology and
- To whom correspondence should be addressed. E-mail:
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15
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Ishii M, Hashimoto M, Oguma K, Kano R, Moritomo T, Hasegawa A. Molecular cloning and tissue expression of canine Toll-like receptor 2 (TLR2). Vet Immunol Immunopathol 2006; 110:87-95. [PMID: 16260044 DOI: 10.1016/j.vetimm.2005.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Revised: 08/25/2005] [Accepted: 09/08/2005] [Indexed: 11/25/2022]
Abstract
Toll-like receptor 2 (TLR2) is involved in an important role on inflammatory reactions against various pathogenic microorganisms. Although some investigations suggested a relation between human and murine TLR2 gene polymorphisms and infections or inflammatory reactions, canine TLR2 gene has not been investigated. In the present study, therefore, the canine full-length of cDNA of Toll-like receptor 2 gene was sequenced and the expression of canine TLR2 mRNA was investigated in various tissues. Canine TLR2 clone was 2552bp encoding 785 amino acids. The similarities of canine TLR2 with human, mouse, rat, cattle, horse and pig TLR2 were 87.6, 72.9, 73.2, 83.1, 85.1 and 80.7% at the nucleotide sequence level, and 84.6, 68.7, 68.5, 78.8, 82.9 and 79.0% at amino acid sequence level, respectively. By a semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis, mRNA of canine TLR2 was detected in blood mononuclear cells (BMCs), lymph node, lung, liver, spleen, bladder, pancreas, small intestine, large intestine and skin of the dogs.
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Affiliation(s)
- Mario Ishii
- Department of Pathobiology, Nihon University School of Veterinary Medicine, 1866 Kameino, Fujisawa, Kanagawa 252-8510, Japan
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Abstract
B cells play a key role in regulating the immune system by producing antibodies, acting as antigen-presenting cells, providing support to other mononuclear cells, and contributing directly to Inflammatory pathways. Accumulating evidence points to disruption of these tightly regulated processes in the pathogenesis of autoimmune disorders. Although the exact mechanisms involved remain to be elucidated, a fundamental feature of many autoimmune disorders is a loss of B-cell tolerance and the inappropriate production of autoantibodies. Dysfunctional immune responses resulting from genetic mutations that cause intrinsic B-cell abnormalities and induction of autoimmunity in the T-cell compartment by B cells that have broken tolerance may also contribute to these disorders. These findings provide the rationale for B-cell depletion as a potential therapeutic strategy in autoimmune disorders and other disease states characterized by inappropriate immune responses. Preliminary results with the CD20-targeted monoclonal antibody rituximab indicate that rituximab can improve symptoms in a number of autoimmune and neurologic disorders (including rheumatoid arthritis, systemic lupus erythematosus, and paraneoplastic neurologic syndromes). Additional studies are warranted to further characterize the role of B cells in autoimmune diseases and the therapeutic utility of B-cell depletion.
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Affiliation(s)
- Robert H Carter
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, 409 LHRB, Birmingham, AL 35294-0007, USA.
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Abstract
PURPOSE OF REVIEW A hallmark of systemic lupus erythematosus is the production of autoantibodies that recognize nuclear antigens. However, the underlying events and mechanisms that lead to the selection of these molecules for the autoimmune response remain poorly understood. In this review, we will examine some of the proposed explanations for sources of systemic lupus erythematosus-specific autoantigens. We will focus on events related to apoptosis, viral infection, cytokine production, innate immune system components, and alternative splicing of pre-mRNA transcripts. RECENT FINDINGS Definitive proof of a viral etiology for lupus remains elusive. However, recent observations have added to increasing evidence that viruses contribute to the bypass of tolerance in systemic lupus erythematosus. Also, events associated with apoptosis - most notably proteolytic autoantigen cleavage by caspases and granzyme B - have been implicated in the initiation of autoimmune responses for over a decade. Results obtained from animal models and human systems suggest complex functions for pro-apoptotic pathways in the regulation of immune responses. Inducible antigen expression and alternatively spliced transcripts may represent additional ways of generating autoantigenic material. Finally, toll-like receptor family members may play critical roles in the induction of antibody responses to nucleic acids in systemic lupus erythematosus. SUMMARY Several factors may contribute to the generation of systemic lupus erythematosus-specific autoantigens. Determining the underlying causes of autoantibody production may provide important insight into the etiology and pathogenesis of this disease.
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Affiliation(s)
- Kareem L Graham
- Stanford University School of Medicine, Division of Immunology and Rheumatology, CA 94305, USA
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Iribarren P, Chen K, Hu J, Gong W, Cho EH, Lockett S, Uranchimeg B, Wang JM. CpG-containing oligodeoxynucleotide promotes microglial cell uptake of amyloid beta 1-42 peptide by up-regulating the expression of the G-protein- coupled receptor mFPR2. FASEB J 2005; 19:2032-4. [PMID: 16219804 DOI: 10.1096/fj.05-4578fje] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Human G protein-coupled formyl peptide receptor like 1 (FPRL1) and its mouse homologue murine formyl peptide receptor 2 (mFPR2) mediate the chemotactic activity of amyloid beta 1-42 (Abeta42), a key pathogenic peptide in Alzheimer's disease (AD). Since mFPR2 is up-regulated in mouse microglia by lipopolysaccharide (LPS), a Toll-like receptor 4 ligand, we investigated the capacity of CpG-containing oligodeoxynucleotide (ODN), a Toll-like receptor (TLR) 9 ligand, to regulate the expression of mFPR2 in mouse microglia. CpG ODN markedly enhanced the expression and function of mFPR2 in microglial cells, which exhibited increased chemotactic responses to mFPR2 agonists, including Abeta42. The effect of CpG ODN is dependent on activation of p38 MAPK. Further studies showed that CpG ODN-treated microglia increased their capacity to endocytose Abeta42 through mFPR2, as this process was abrogated by pertussis toxin, a Gi protein inhibitor, and W peptide, another potent mFPR2 agonist. Our results suggest that TLR9 may play an important role in promoting microglial recognition of Abeta42, thus affecting the pathogenic process of AD.
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Affiliation(s)
- Pablo Iribarren
- Laboratory of Molecular Immunoregulation, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702-1201, USA
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Anders HJ, Patole PS. Toll-like receptors recognize uropathogenic Escherichia coli and trigger inflammation in the urinary tract. Nephrol Dial Transplant 2005; 20:1529-32. [PMID: 15941847 DOI: 10.1093/ndt/gfh922] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
"Nature has provided, in the white corpuscles as you call them-in the phagocytes as we call them-a natural means of devouring and destroying all disease germs. There is at bottom only one genuinely scientific treatment for all diseases, and that is to stimulate the phagocytes." So opined B.B. in G.B. Shaw's The Doctor's Dilemma in a dramatic restatement of a key portion of Ilya Metchnikoff's Nobel Prize address: "Whenever the organism enjoys immunity, the introduction of infectious microbes is followed by the accumulation of mobile cells, of white corpuscles of the blood in particular which absorb the microbes and destroy them. The white corpuscles and the other cells capable of doing this have been designated 'phagocytes,' (i.e., devouring cells) and the whole function that ensures immunity has been given the name of 'phagocytosis'". Based on these insights into the foundation of resistance to infectious disease, Metchnikoff was awarded the 1908 Nobel Prize in Physiology or Medicine together with Paul Ehrlich (Fig. 1). Although both were cited for discoveries in immunity, the contributions of the two men seem worlds apart. Ehrlich's studies did not deal with generic responses to infection, but rather with the highly specific nature of antibodies and their relationship to the cells producing them: "As the cell receptor is obviously preformed, and the artificially produced antitoxin only the consequence, i.e. secondary, one can hardly fail to assume that the antitoxin is nothing else but discharged components of the cell, namely receptors discharged in excess". But biological systems are just that-systems-and the parts need to work together. And so we arrive, a century later, at an appreciation for just how intimately related these two seemingly disparate aspects of host defense really are.
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Affiliation(s)
- Ronald N Germain
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Tobias P, Curtiss LK. Thematic review series: The immune system and atherogenesis. Paying the price for pathogen protection: toll receptors in atherogenesis. J Lipid Res 2005; 46:404-11. [PMID: 15654120 DOI: 10.1194/jlr.r400015-jlr200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atherosclerosis is a chronic inflammatory response characterized by the accumulation of cells of innate and acquired immune systems within the intima of the arterial wall. Macrophages are the predominant participant in innate immune responses in atherosclerosis. Protein receptors expressed by macrophages and endothelial cells recognize components and products of microorganisms and play a vital role in innate immunity. In particular, the members of the toll-like receptor (TLR) family play a critical role in the inflammatory components of atherosclerosis. Both exogenous ligands involved in microbial recognition as well as endogenous ligands involved in sterile inflammation pathways are implicated in the pathology of atherosclerosis. In this review, we discuss our current understanding of the role of TLRs and their coactivators in atherosclerosis, with particular emphasis on studies in atherosclerosis-prone hypercholesterolemic mice.
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Affiliation(s)
- Peter Tobias
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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