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Torres-Ruiz J, Carrillo-Vazquez DA, Padilla-Ortiz DM, Vazquez-Rodriguez R, Nuñez-Alvarez C, Juarez-Vega G, Gomez-Martin D. TLR expression in peripheral monocyte subsets of patients with idiopathic inflammatory myopathies: association with clinical and immunological features. J Transl Med 2020; 18:125. [PMID: 32164729 PMCID: PMC7066841 DOI: 10.1186/s12967-020-02290-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/04/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Monocytes and toll-like receptors (TLR) have been found in the inflammatory infiltrate of muscle biopsies in patients with idiopathic inflammatory myopathies (IIM), suggesting an important role of these cells in the pathogenesis of myositis. The monocyte subsets, their TLR expression in peripheral blood and their relationship with the clinical characteristics of patients with IIM has not been addressed. METHODS We recruited 45 patients with IIM diagnosis and 15 age and sex-adjusted healthy controls. We assessed the disease activity and damage, performed a nailfold capillaroscopy and registered the cardio-pulmonary parameters from the medical charts. Monocyte subsets, their expression of TLR2 and TLR4 and the serum Th1/Th2/Th17 cytokines levels were evaluated by flow cytometry. We expressed quantitative variables as medians and interquartile ranges (IQR) or minimum and maximum (min-max). Differences between groups were assessed with Mann-Whitney U and the Kruskal-Wallis tests. Correlation between quantitative variables was assessed with Spearman Rho. RESULTS Twenty-nine patients were women (64.4%) and 32 (71.1%) had dermatomyositis. In comparison to healthy controls, patients with active IIM had a higher percentage of intermediate monocytes and lower amounts of classical monocytes. Patients with IIM had a higher expression of TLR4 in all their monocyte subsets, regardless of disease activity and prednisone treatment. Serum IL-6 correlated with the TLR2 expression in every monocyte subset and the expression of TLR2 in intermediate monocytes was higher among patients with dysphagia. Subjects with nailfold capillaroscopy abnormalities had a higher amount of TLR2+ classical and non-classical monocytes and those with interstitial lung disease (ILD) had a higher percentage of TLR4+ non-classical monocytes. The classical and intermediate monocytes from patients with anti Mi2 antibodies had a higher expression of TLR4. The percentage of intermediate monocytes and the expression of TLR4 in all monocyte subsets showed a good diagnostic capacity in patients with IIM. CONCLUSION Patients with IIM have a differential pool of monocyte subsets with an enhanced expression of TLR2 and TLR4, which correlates with disease activity and distinctive clinical features including dysphagia, ILD, vasculopathy, and pro-inflammatory cytokines. These immunological features might be useful as a potential diagnostic tool as well as novel disease activity biomarkers in IIM.
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Affiliation(s)
- Jiram Torres-Ruiz
- Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Emergency Medicine Department, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Daniel Alberto Carrillo-Vazquez
- Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Diana Marcela Padilla-Ortiz
- Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico.,Universidad de La Sabana, Hospital Militar Central, Bogotá, DC, Colombia
| | - Ricardo Vazquez-Rodriguez
- Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Carlos Nuñez-Alvarez
- Department of Immunology and Rheumatology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Guillermo Juarez-Vega
- Flow Cytometry Unit, Red de Apoyo a la Investigación, Coordinación de Investigación Científica, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Diana Gomez-Martin
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Ave Morones Prieto 3000, 64710, Monterrey, Nuevo Leon, Mexico.
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The role of microbiota in the pathogenesis of lupus: Dose it impact lupus nephritis? Pharmacol Res 2019; 139:191-198. [DOI: 10.1016/j.phrs.2018.11.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 02/06/2023]
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Ding Y, Liu P, Chen ZL, Zhang SJ, Wang YQ, Cai X, Luo L, Zhou X, Zhao L. Emodin Attenuates Lipopolysaccharide-Induced Acute Liver Injury via Inhibiting the TLR4 Signaling Pathway in vitro and in vivo. Front Pharmacol 2018; 9:962. [PMID: 30186181 PMCID: PMC6113398 DOI: 10.3389/fphar.2018.00962] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/03/2018] [Indexed: 12/14/2022] Open
Abstract
Aims: Emodin is an anthraquinone with potential anti-inflammatory properties. However, the possible molecular mechanisms and protective effects of emodin are not clear. The objective of this study was to investigate the possible molecular mechanisms and protective effects of emodin on lipopolysaccharide (LPS)-induced acute liver injury (ALI) via the Toll-like receptor 4 (TLR4) signaling pathway in the Raw264.7 cell line and in Balb/c mice. Methods: This study established an inflammatory cellular model and induced an ALI animal model. TLR4 was overexpressed by lentivirus and downregulated by small interfering RNA (siRNA) technology. The mRNA and protein levels of TLR4 and downstream molecules were detected in cells and liver tissue. The tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 levels in supernatant and serum were determined by ELISA. The distribution and expression of mannose receptor C type 1 (CD206) and arginase 1 (ARG1) in the liver were tested by immunofluorescence. Mouse liver function and histopathological observations were assessed. Results: Administration of emodin reduced the protein and/or mRNA levels of TLR4 and its downstream molecules following LPS challenge in Raw264.7 cells and in an animal model. Additionally, emodin suppressed the expression of TNF-α and IL-6 in cell culture supernatant and serum. The inhibitory effect of emodin was also confirmed in RAW264.7 cells, in which TLR4 was overexpressed or knocked down. Additionally, ARG1 and CD206 were elevated in the emodin groups. Emodin also decreased serum ALT and AST levels and alleviated the liver histopathological damage induced by LPS. Conclusion: Emodin showed excellent hepatoprotective effects against LPS-induced ALI, possibly by inhibiting TLR4 signaling pathways.
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Affiliation(s)
- Yan Ding
- Department of Infectious Diseases and Immunology, Wuhan Children's Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pan Liu
- School of Clinical Medicine, Hubei University of Chinese Medicine, Wuhan, China
| | - Zhi-Lin Chen
- Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shao-Jun Zhang
- National and Local Joint Engineering Research Center for High-throughput Drug Screening Technology, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei University, Wuhan, China
| | - You-Qin Wang
- Graduate School of Jinzhou Medical University, Department of Pediatrics, Renmin Hospital, Hubei University of Medicine, Shiyan, China
| | - Xin Cai
- School of Clinical Medicine, Hubei University of Chinese Medicine, Wuhan, China
| | - Lei Luo
- School of Clinical Medicine, Hubei University of Chinese Medicine, Wuhan, China
| | - Xuan Zhou
- Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Zhao
- Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Sciorati C, Monno A, Doglio MG, Rigamonti E, Ascherman DP, Manfredi AA, Rovere-Querini P. Exacerbation of Murine Experimental Autoimmune Myositis by Toll-Like Receptor 7/8. Arthritis Rheumatol 2018; 70:1276-1287. [PMID: 29569859 DOI: 10.1002/art.40503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/15/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Toll-like receptor 7 (TLR-7), TLR-8, and interferon (IFN)-induced genes are expressed in patients with idiopathic inflammatory myositis. This study was undertaken to investigate whether their activation influences the natural history of the disease. METHODS Experimental autoimmune myositis was induced in mice by injection of the amino-terminal portion of the murine histidyl-transfer RNA synthetase (HisRS). Disease was compared in the presence or the absence of the TLR-7/8 agonist R-848 in wild-type mice and in mice that fail to express the IFNα/β receptor (IFNα/βR-null mice). RESULTS Experimental autoimmune myositis induced by a single intramuscular immunization with HisRS spontaneously abated after 7-8 weeks. In contrast, levels of anti-HisRS autoantibodies, endomysial/perimysial leukocyte infiltration, and myofiber regeneration persisted at the end of the follow-up period (22 weeks after immunization) in mice immunized with HisRS in the presence of R-848. Myofiber major histocompatibility complex (MHC) class I molecules were detectable only in mice immunized with both HisRS and R-848. MHC up-regulation occurred early and in muscles that were not directly injected with HisRS. Muscle MHC expression paralleled with leukocyte infiltration. MHC class I molecules were selectively up-regulated in myotubes challenged with R-848 in vitro. Type I IFN was necessary for the prolonged autoantibody response and for the spreading of the autoimmune response, as demonstrated using IFNα/βR-null mice. Muscle infiltration was maintained in the injected muscle up to the end of the follow-up period. CONCLUSION TLR-7/8 activation is necessary to induce and maintain a systemic autoimmune response targeting the skeletal muscle. This experimental autoimmune myositis model reproduces many characteristics of human idiopathic inflammatory myopathies and may represent a tool for preclinical studies.
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Affiliation(s)
- Clara Sciorati
- IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Antonella Monno
- IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | | | - Elena Rigamonti
- IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | | | - Angelo A Manfredi
- IRCCS Ospedale San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy
| | - Patrizia Rovere-Querini
- IRCCS Ospedale San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy
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5
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Abstract
Histopathological analyses of muscle specimens from myositis patients indicate that skeletal muscle cells play an active role in the interaction with immune cells. Research over the last few decades has shown that skeletal muscle cells exhibit immunobiological properties that perfectly define them as non-professional antigen presenting cells. They are able to present antigens via major histocompatibility complex molecules, exhibit costimulatory molecules and secrete soluble molecules that actively shape the immune response in an either pro- or anti-inflammatory manner. Skeletal muscle cells regulate both innate and adaptive immune responses and are essentially involved in the pathophysiological processes of idiopathic inflammatory myopathies. Understanding the role of skeletal muscle cells might help to identify new therapeutic targets for these devastating diseases. This review summarizes the immunobiological features of skeletal muscle cells, especially in the context of idiopathic inflammatory myopathies, and discusses shortcomings and limitations in skeletal muscle related research providing potential perspectives to overcome them in the future.
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Affiliation(s)
- Ali Maisam Afzali
- Department of Neurology, Klinikum Rechts der Isar, Technical University of Munich, Germany; Department of Neurology, University of Münster, Germany
| | | | - Heinz Wiendl
- Department of Neurology, University of Münster, Germany
| | - Sven G Meuth
- Department of Neurology, University of Münster, Germany
| | - Tobias Ruck
- Department of Neurology, University of Münster, Germany.
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6
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Afzali AM, Ruck T, Wiendl H, Meuth SG. Animal models in idiopathic inflammatory myopathies: How to overcome a translational roadblock? Autoimmun Rev 2017; 16:478-494. [DOI: 10.1016/j.autrev.2017.03.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 02/13/2017] [Indexed: 12/19/2022]
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Dysregulated innate immune function in the aetiopathogenesis of idiopathic inflammatory myopathies. Autoimmun Rev 2016; 16:87-95. [PMID: 27666811 DOI: 10.1016/j.autrev.2016.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 09/08/2016] [Indexed: 12/20/2022]
Abstract
The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic muscle conditions that are believed to be autoimmune in nature. They have distinct pathological features, but the aetiopathogenesis of each subtype remains largely unknown. Recently, there has been increased interest in the complex role the innate immune system plays in initiating and perpetuating these conditions, and how this may differ between subtypes. This article summarises the traditional paradigms of IIM pathogenesis and reviews the accumulating evidence for disturbances in innate immune processes in these rare, but debilitating chronic conditions.
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Aggarwal R, Oddis CV, Goudeau D, Koontz D, Qi Z, Reed AM, Ascherman DP, Levesque MC. Autoantibody levels in myositis patients correlate with clinical response during B cell depletion with rituximab. Rheumatology (Oxford) 2016; 55:991-9. [PMID: 26888854 DOI: 10.1093/rheumatology/kev444] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES To determine the longitudinal trends in serum levels of four myositis-associated autoantibodies: anti-Jo-1, -transcription intermediary factor 1 γ (TIF1-γ), -signal recognition particle (SRP) and -Mi-2, after B cell depletion with rituximab, and to determine the longitudinal association of these autoantibody levels with disease activity as measured by myositis core-set measures (CSMs). METHODS Treatment-resistant adult and pediatric myositis subjects (n = 200) received rituximab in the 44-week Rituximab in Myositis Trial. CSMs [muscle enzymes, manual muscle testing (MMT), physician and patient global disease activity, HAQ, and extramuscular disease activity] were evaluated monthly and anti-Jo-1 (n = 28), -TIF1-γ (n = 23), -SRP (n = 25) and -Mi-2 (n = 26) serum levels were measured using validated quantitative ELISAs. Temporal trends and the longitudinal relationship between myositis-associated autoantibodies levels and CSM were estimated using linear mixed models. RESULTS Following rituximab, anti-Jo-1 levels decreased over time (P < 0.001) and strongly correlated with all CSMs (P < 0.008). Anti-TIF1-γ levels also decreased over time (P < 0.001) and were only associated with HAQ, MMT and physician and patient global disease activity. Anti-SRP levels did not change significantly over time, but were significantly associated with serum muscle enzymes. Anti-Mi-2 levels significantly decreased over time and were associated with muscle enzymes, MMT and the physician global score. CONCLUSION Anti-Jo-1, anti-TIF1-γ and anti-Mi-2 levels in myositis subjects decreased after B cell depletion and were correlated with changes in disease activity, whereas anti-SRP levels were only associated with longitudinal muscle enzyme levels. The strong association of anti-Jo-1 levels with clinical outcomes suggests that anti-Jo-1 autoantibodies may be a good biomarker for disease activity.
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Affiliation(s)
- Rohit Aggarwal
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh Department of Medicine, Pittsburgh, PA,
| | - Chester V Oddis
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh Department of Medicine, Pittsburgh, PA
| | - Danielle Goudeau
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh Department of Medicine, Pittsburgh, PA
| | - Diane Koontz
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh Department of Medicine, Pittsburgh, PA
| | - Zengbiao Qi
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh Department of Medicine, Pittsburgh, PA
| | - Ann M Reed
- Department of Pediatrics, Duke University School of Medicine, Durham, NC and
| | - Dana P Ascherman
- Division of Rheumatology and Immunology, University of Miami Department of Medicine, Miami, FL, USA
| | - Marc C Levesque
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh Department of Medicine, Pittsburgh, PA
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9
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Mu Q, Zhang H, Luo XM. SLE: Another Autoimmune Disorder Influenced by Microbes and Diet? Front Immunol 2015; 6:608. [PMID: 26648937 PMCID: PMC4663251 DOI: 10.3389/fimmu.2015.00608] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 11/16/2015] [Indexed: 12/20/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease. Despite years of study, the etiology of SLE is still unclear. Both genetic and environmental factors have been implicated in the disease mechanisms. In the past decade, a growing body of evidence has indicated an important role of gut microbes in the development of autoimmune diseases, including type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. However, such knowledge on SLE is little, though we have already known that environmental factors can trigger the development of lupus. Several recent studies have suggested that alterations of the gut microbial composition may be correlated with SLE disease manifestations, while the exact roles of either symbiotic or pathogenic microbes in this disease remain to be explored. Elucidation of the roles of gut microbes - as well as the roles of diet that can modulate the composition of gut microbes - in SLE will shed light on how this autoimmune disorder develops, and provide opportunities for improved biomarkers of the disease and the potential to probe new therapies. In this review, we aim to compile the available evidence on the contributions of diet and gut microbes to SLE occurrence and pathogenesis.
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Affiliation(s)
- Qinghui Mu
- Department of Biomedical Sciences and Pathobiology, Virginia Tech , Blacksburg, VA , USA
| | - Husen Zhang
- Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, VA , USA
| | - Xin M Luo
- Department of Biomedical Sciences and Pathobiology, Virginia Tech , Blacksburg, VA , USA
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10
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Heterogeneity of autoimmune diseases: pathophysiologic insights from genetics and implications for new therapies. Nat Med 2015; 21:730-8. [PMID: 26121193 DOI: 10.1038/nm.3897] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 06/08/2015] [Indexed: 02/08/2023]
Abstract
Recent advances in genome-wide association studies (GWAS) across autoimmune and immune-mediated diseases have augmented our understanding of pathogenic mechanisms underlying these diseases. This has further highlighted their heterogeneous nature, both within and between diseases. Furthermore, varying responses to therapy have also served to underline the importance of this heterogeneity in the manner in which these diseases are diagnosed and treated. Here we discuss our current understanding of the shared pathways of autoimmunity, including the tumor necrosis factor (TNF), major histocompatibility complex (MHC), interleukin 23 receptor (IL23R) and protein tyrosine phosphatase non-receptor type 22 (PTPN22) pathways. In addition, we summarize effective specific therapies tested across major autoimmune diseases, highlighting the insight they have provided into disease mechanisms and their implications for potential future improvements.
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Janssen E, Ozcan E, Liadaki K, Jabara HH, Manis J, Ullas S, Akira S, Fitzgerald KA, Golenbock DT, Geha RS. TRIF signaling is essential for TLR4-driven IgE class switching. THE JOURNAL OF IMMUNOLOGY 2014; 192:2651-8. [PMID: 24532577 DOI: 10.4049/jimmunol.1300909] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The TLR4 ligand LPS causes mouse B cells to undergo IgE and IgG1 isotype switching in the presence of IL-4. TLR4 activates two signaling pathways mediated by the adaptor molecules MyD88 and Toll/IL-IR domain-containing adapter-inducing IFN-β (TRIF)-related adaptor molecule (TRAM), which recruits TRIF. Following stimulation with LPS plus IL-4, Tram(-/-) and Trif(-/-) B cells completely failed to express Cε germline transcripts (GLT) and secrete IgE. In contrast, Myd88(-/-) B cells had normal expression of Cε GLT but reduced IgE secretion in response to LPS plus IL-4. Following LPS plus IL-4 stimulation, Cγ1 GLT expression was modestly reduced in Tram(-/-) and Trif(-/-) B cells, whereas Aicda expression and IgG1 secretion were reduced in Tram(-/-), Trif(-/-), and Myd88(-/-) B cells. B cells from all strains secreted normal amounts of IgE and IgG1 in response to anti-CD40 plus IL-4. Following stimulation with LPS plus IL-4, Trif(-/-) B cells failed to sustain NF-κB p65 nuclear translocation beyond 3 h and had reduced binding of p65 to the Iε promoter. Addition of the NF-κB inhibitor, JSH-23, to wild-type B cells 15 h after LPS plus IL-4 stimulation selectively blocked Cε GLT expression and IgE secretion but had little effect on Cγ1 GLT expression and IgG secretion. These results indicate that sustained activation of NF-κB driven by TRIF is essential for LPS plus IL-4-driven activation of the Cε locus and class switching to IgE.
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Affiliation(s)
- Erin Janssen
- Division of Immunology, Boston Children's Hospital, Boston, MA 02115
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12
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Jiang W, Gilkeson G. Sex Differences in monocytes and TLR4 associated immune responses; implications for systemic lupus erythematosus (SLE). ACTA ACUST UNITED AC 2014; 1:1. [PMID: 25309746 DOI: 10.7243/2055-2394-1-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It has been shown that TLR7 and TLR9 signaling play a role in SLE pathogenesis. Our recent study revealed that estrogen receptor α knockout mice have impaired inflammatory responses to TLR3, TLR4, TLR7 and TLR9 ligand stimulation in DCs, B cells and whole spleen cells. These findings indicate that estrogen receptor mediated signaling may impact universal TLR responsiveness. Whether estrogen has a direct or indirect effect on TLR responsiveness by immune cells is not clear. There is evidence of a role of TLR4 in SLE disease pathogenesis, such as the kidney damage, the induction of CD40 and autoantibodies, the suppression of regulatory T cells, and the role of pro-inflammatory cytokines (e.g., IL-6, IL-1β, TNF-α) in SLE pathogenesis that can be induced by TLR4-mediated monocyte activation, suggesting that TLR4 and TLR4 responsiveness are also important for SLE disease. This review will focus on TLR4 responses and monocytes, which are understudied in systemic autoimmune diseases such as SLE.
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Affiliation(s)
- Wei Jiang
- Department of Microbiology and Immunology, Division of Infectious Diseases, Department of Medicine, Medical University of South Carolina
| | - Gary Gilkeson
- Division of Rheumatology, Department of Medicine, Medical University of South Carolina
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Abstract
Although alopecia areata (AA) is not life threatening, it may lead to severe psychological disturbances, reducing the quality of life in all ages. Thus, a new animal model is needed for shedding more light onto the pathogenesis of this cell-mediated, organ-specific autoimmune disease to identify more effective therapeutic strategies. Recently, we succeeded in developing a new humanized mouse model of AA, which includes transplantation of healthy human scalp skin obtained from normal volunteers on to severe-combined immunodeficient mice. This is followed by intradermal injection of either autologous or allogeneic peripheral blood mononuclear cells, which had been cultured with high dose of IL-2 and enriched for natural killer group 2D-positive (NKG2D+) and CD56+ cells. This protocol leads to rapid and predictable development of focal hair loss, with all the characteristic clinical, histological, and immunohistochemical features of AA. This humanized mouse AA model underscores the functional importance of NKG2D+ and CD56+ cells in AA pathogenesis and promises to be instrumental for identifying novel AA treatment strategies.
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Affiliation(s)
- Amos Gilhar
- Skin Research Laboratory, Faculty of Medicine, Technion-Israel Institute of Technology and Flieman Medical Center, Haifa, Israel
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14
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Fernandez I, Harlow L, Zang Y, Liu-Bryan R, Ridgway WM, Clemens PR, Ascherman DP. Functional redundancy of MyD88-dependent signaling pathways in a murine model of histidyl-transfer RNA synthetase-induced myositis. THE JOURNAL OF IMMUNOLOGY 2013; 191:1865-72. [PMID: 23842751 DOI: 10.4049/jimmunol.1203070] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We have previously shown that i.m. administration of bacterially expressed murine histidyl-tRNA synthetase (HRS) triggers florid muscle inflammation (relative to appropriate control proteins) in various congenic strains of mice. Because severe disease develops even in the absence of adaptive immune responses to HRS, we sought to identify innate immune signaling components contributing to our model of HRS-induced myositis. In vitro stimulation assays demonstrated HRS-mediated activation of HEK293 cells transfected with either TLR2 or TLR4, revealing an excitatory capacity exceeding that of other bacterially expressed fusion proteins. Corresponding to this apparent functional redundancy of TLR signaling pathways, HRS immunization of B6.TLR2(-/-) and B6.TLR4(-/-) single-knockout mice yielded significant lymphocytic infiltration of muscle tissue comparable to that produced in C57BL/6 wild-type mice. In contrast, concomitant elimination of TLR2 and TLR4 signaling in B6.TLR2(-/-).TLR4(-/-) double-knockout mice markedly reduced the severity of HRS-induced muscle inflammation. Complementary subfragment analysis demonstrated that aa 60-90 of HRS were absolutely required for in vitro as well as in vivo signaling via these MyD88-dependent TLR pathways--effects mediated, in part, through preferential binding of exogenous ligands capable of activating specific TLRs. Collectively, these experiments indicate that multiple MyD88-dependent signaling cascades contribute to this model of HRS-induced myositis, underscoring the antigenic versatility of HRS and confirming the importance of innate immunity in this system.
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Affiliation(s)
- Irina Fernandez
- Division of Rheumatology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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15
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Rayavarapu S, Coley W, Kinder TB, Nagaraju K. Idiopathic inflammatory myopathies: pathogenic mechanisms of muscle weakness. Skelet Muscle 2013; 3:13. [PMID: 23758833 PMCID: PMC3681571 DOI: 10.1186/2044-5040-3-13] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 04/22/2013] [Indexed: 11/25/2022] Open
Abstract
Idiopathic inflammatory myopathies (IIMs) are a heterogenous group of complex muscle diseases of unknown etiology. These diseases are characterized by progressive muscle weakness and damage, together with involvement of other organ systems. It is generally believed that the autoimmune response (autoreactive lymphocytes and autoantibodies) to skeletal muscle-derived antigens is responsible for the muscle fiber damage and muscle weakness in this group of disorders. Therefore, most of the current therapeutic strategies are directed at either suppressing or modifying immune cell activity. Recent studies have indicated that the underlying mechanisms that mediate muscle damage and dysfunction are multiple and complex. Emerging evidence indicates that not only autoimmune responses but also innate immune and non-immune metabolic pathways contribute to disease pathogenesis. However, the relative contributions of each of these mechanisms to disease pathogenesis are currently unknown. Here we discuss some of these complex pathways, their inter-relationships and their relation to muscle damage in myositis. Understanding the relative contributions of each of these pathways to disease pathogenesis would help us to identify suitable drug targets to alleviate muscle damage and also improve muscle weakness and quality of life for patients suffering from these debilitating muscle diseases.
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Affiliation(s)
- Sree Rayavarapu
- Research Center for Genetic Medicine, Children's National Medical Center, 111 Michigan Ave NW, Washington DC, USA.
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