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Zhang T, Ma N, Wang J, Min X, Wei L, Li K. C5aR2 Deficiency Lessens C5aR1 Distribution and Expression in Neutrophils and Macrophages. J Immunol Res 2024; 2024:2899154. [PMID: 39021433 PMCID: PMC11254461 DOI: 10.1155/2024/2899154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 06/05/2024] [Accepted: 06/20/2024] [Indexed: 07/20/2024] Open
Abstract
As another receptor for complement activation product C5a, C5aR2 has been paid much attention these years. Although controversial and complex, its specific signals or roles in modulating the classic receptor C5aR1 have been investigated and gradually revealed. The hypothesis of the heterodimer of C5aR1 and C5aR2 has also been suggested and observed under extremely high C5a concentrations. In this article, we tried to investigate whether C5aR2 would affect C5aR1 expression under normal or inflammatory conditions in WT and C5ar2 -/- mice of C57BL/6 background. We focused on the innate immune cells-neutrophils and macrophages. The mRNA levels of C5ar1 in normal kidney, liver, and the mRNA or protein levels of naïve-bone marrow and peripheral blood leukocytes and peritoneal Mφs were comparable between WT and C5ar2 -/- mice, indicating the technique of C5aR2 knockout did not affect the transcription of its neighboring gene C5aR1. However, the mean fluorescence intensity of surface C5aR1 on naïve circulating C5ar2 -/- neutrophils detected by FACS was reduced, which might be due to the reduced internalization of C5aR1 on C5ar2 -/- neutrophils. In the peritonitis model induced by i.p. injection of thioglycollate, more neutrophils were raised after 10 hr in C5ar2 -/- peritoneal cavity, indicating the antagonism of C5aR2 on C5aR1 signal in neutrophil chemotaxis. After 3 days of thioglycollate injection, the mainly infiltrating macrophages were comparable between WT and C5ar2 -/- mice, but the C5ar1 mRNA and surface or total C5aR1 protein expression were both reduced in C5ar2 -/- macrophages, combined with our previous study of reduced chemokines and cytokines expression in C5ar2 -/- peritoneal macrophages, indicating that C5aR2 in macrophages may cooperate with C5aR1 inflammatory signals. Our article found C5aR2 deficiency lessened C5aR1 distribution and expression in neutrophils and macrophages with different functions, indicating C5aR2 might function differently in different cells.
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Affiliation(s)
- Ting Zhang
- Department of PathologyThe Second Affiliated HospitalSchool of MedicineXi'an Jiaotong University, Xi'an 710004, China
- Core Research LaboratoryThe Second Affiliated HospitalSchool of MedicineXi'an Jiaotong University, Xi'an 710004, China
| | - Ning Ma
- Core Research LaboratoryThe Second Affiliated HospitalSchool of MedicineXi'an Jiaotong University, Xi'an 710004, China
| | - Jiaxing Wang
- Institute of HematologySchool of MedicineNorthwest University, Xi'an 710069, China
| | - Xiaoyun Min
- Core Research LaboratoryThe Second Affiliated HospitalSchool of MedicineXi'an Jiaotong University, Xi'an 710004, China
| | - Linlin Wei
- Core Research LaboratoryThe Second Affiliated HospitalSchool of MedicineXi'an Jiaotong University, Xi'an 710004, China
| | - Ke Li
- Core Research LaboratoryThe Second Affiliated HospitalSchool of MedicineXi'an Jiaotong University, Xi'an 710004, China
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Fujita Y, Matsumoto H, Inada K, Onizawa M, Saito K, Sumichika Y, Yoshida S, Temmoku J, Matsuoka N, Asano T, Sato S, Machida T, Migita K. C5a stimulation induces caspase-1 activation and mature IL-1β production in human peripheral blood mononuclear cells. Immunol Med 2024; 47:68-75. [PMID: 38099557 DOI: 10.1080/25785826.2023.2292665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 12/03/2023] [Indexed: 05/25/2024] Open
Abstract
The complement component C5a contributes to the recruitment of immune cells to inflamed tissues and local inflammation. The proinflammatory cytokine interleukin (IL)-1β is also related to inflammatory disorders through inflammasome activation. However, the association between inflammasome activation and C5a is unclear. Human peripheral blood mononuclear cells (PBMCs) were stimulated with C5a and measured for IL-1β secretion by enzyme-linked immunosorbent assay (ELISA). The pro-IL-1β expression in cell lysates was also examined by Western blot analysis. Similarly, magnetic bead-isolated CD14+ monocyte-depleted and lymphocyte-depleted PBMCs were stimulated with C5a, and immunoblot analysis was performed using an anti-cleaved-IL-1β (p17) antibody. FACS was performed to detect caspase-1-activated cells. C5a-stimulated PBMCs produced IL-1β in C5a concentration-dependent manner. The protein levels of pro-IL-1β in the cell lysates were significantly increased. Furthermore, the cleaved-IL-1β (p17) was faintly detected in the same lysates. Active caspase-1 was demonstrated in C5a-simulated CD14+ monocytes by FACS. Cleaved-IL-1β (p17) was demonstrated in the supernatant of C5a-stimulated PBMCs. Lymphocyte-depleted PBMCs stimulated with C5a but monocyte-depleted PBMCs produced cleaved-IL-1β (p17). C5a induced the production of mature IL-1β in PBMCs. The IL-1β production is mediated mainly by caspase-1 activation in CD14+ monocytes. These results suggest that C5a alone potentiates mature IL-1β production mainly in monocytes.
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Affiliation(s)
- Yuya Fujita
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Haruki Matsumoto
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Kenji Inada
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Michio Onizawa
- Department of Gastroenterology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Kenji Saito
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Yuya Sumichika
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Shuhei Yoshida
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Jumpei Temmoku
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Naoki Matsuoka
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Tomoyuki Asano
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Shuzo Sato
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Takeshi Machida
- Department of Immunology, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Kiyoshi Migita
- Department of Rheumatology, Fukushima Medical University School of Medicine, Fukushima, Japan
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Wright O, Harris A, Nguyen VD, Zhou Y, Durand M, Jayyaratnam A, Gormley D, O'Neill LAJ, Triantafilou K, Nichols EM, Booty LM. C5aR2 Regulates STING-Mediated Interferon Beta Production in Human Macrophages. Cells 2023; 12:2707. [PMID: 38067135 PMCID: PMC10706378 DOI: 10.3390/cells12232707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/12/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
The complement system mediates diverse regulatory immunological functions. C5aR2, an enigmatic receptor for anaphylatoxin C5a, has been shown to modulate PRR-dependent pro-inflammatory cytokine secretion in human macrophages. However, the specific downstream targets and underlying molecular mechanisms are less clear. In this study, CRISPR-Cas9 was used to generate macrophage models lacking C5aR2, which were used to probe the role of C5aR2 in the context of PRR stimulation. cGAS and STING-induced IFN-β secretion was significantly increased in C5aR2 KO THP-1 cells and C5aR2-edited primary human monocyte-derived macrophages, and STING and IRF3 expression were increased, albeit not significantly, in C5aR2 KO cell lines implicating C5aR2 as a regulator of the IFN-β response to cGAS-STING pathway activation. Transcriptomic analysis by RNAseq revealed that nucleic acid sensing and antiviral signalling pathways were significantly up-regulated in C5aR2 KO THP-1 cells. Altogether, these data suggest a link between C5aR2 and nucleic acid sensing in human macrophages. With further characterisation, this relationship may yield therapeutic options in interferon-related pathologies.
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Affiliation(s)
- Oliver Wright
- Immunology Network, GSK, Stevenage SG1 2NY, UK
- School of Biochemistry and Immunology, Trinity College Dublin, D02 VR66 Dublin, Ireland
| | - Anna Harris
- Immunology Network, GSK, Stevenage SG1 2NY, UK
| | - Van Dien Nguyen
- Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XW, UK
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XW, UK
| | - You Zhou
- Systems Immunity Research Institute, Cardiff University, Cardiff CF14 4XW, UK
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XW, UK
| | - Maxim Durand
- Immunology Research Unit, GSK, Stevenage SG1 2NY, UK
| | | | | | - Luke A J O'Neill
- School of Biochemistry and Immunology, Trinity College Dublin, D02 VR66 Dublin, Ireland
| | - Kathy Triantafilou
- Immunology Network, GSK, Stevenage SG1 2NY, UK
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XW, UK
| | | | - Lee M Booty
- Immunology Network, GSK, Stevenage SG1 2NY, UK
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Santos-López J, de la Paz K, Fernández FJ, Vega MC. Structural biology of complement receptors. Front Immunol 2023; 14:1239146. [PMID: 37753090 PMCID: PMC10518620 DOI: 10.3389/fimmu.2023.1239146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/16/2023] [Indexed: 09/28/2023] Open
Abstract
The complement system plays crucial roles in a wide breadth of immune and inflammatory processes and is frequently cited as an etiological or aggravating factor in many human diseases, from asthma to cancer. Complement receptors encompass at least eight proteins from four structural classes, orchestrating complement-mediated humoral and cellular effector responses and coordinating the complex cross-talk between innate and adaptive immunity. The progressive increase in understanding of the structural features of the main complement factors, activated proteolytic fragments, and their assemblies have spurred a renewed interest in deciphering their receptor complexes. In this review, we describe what is currently known about the structural biology of the complement receptors and their complexes with natural agonists and pharmacological antagonists. We highlight the fundamental concepts and the gray areas where issues and problems have been identified, including current research gaps. We seek to offer guidance into the structural biology of the complement system as structural information underlies fundamental and therapeutic research endeavors. Finally, we also indicate what we believe are potential developments in the field.
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Affiliation(s)
- Jorge Santos-López
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Karla de la Paz
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Research & Development, Abvance Biotech SL, Madrid, Spain
| | | | - M. Cristina Vega
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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Seiler DL, Kähler KH, Kleingarn M, Sadik CD, Bieber K, Köhl J, Ludwig RJ, Karsten CM. The complement receptor C5aR2 regulates neutrophil activation and function contributing to neutrophil-driven epidermolysis bullosa acquisita. Front Immunol 2023; 14:1197709. [PMID: 37275893 PMCID: PMC10235453 DOI: 10.3389/fimmu.2023.1197709] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/02/2023] [Indexed: 06/07/2023] Open
Abstract
Introduction The function of the second receptor for the complement cleavage product C5a, C5aR2, is poorly understood and often neglected in the immunological context. Using mice with a global deficiency of C5aR2, we have previously reported an important role of this receptor in the pathogenesis of the neutrophil-driven autoimmune disease epidermolysis bullosa acquisita (EBA). Based on in vitro analyses, we hypothesized that the absence of C5aR2 specifically on neutrophils is the cause of the observed differences. Here, we report the generation of a new mouse line with a LysM-specific deficiency of C5aR2. Methods LysM-specific deletion of C5aR2 was achieved by crossing LysMcre mice with tdTomato-C5ar2fl/fl mice in which the tdTomato-C5ar2 gene is flanked by loxP sites. Passive EBA was induced by subcutaneous injection of rabbit anti-mouse collagen type VII IgG. The effects of targeted deletion of C5ar2 on C5a-induced effector functions of neutrophils were examined in in vitro assays. Results We confirm the successful deletion of C5aR2 at both the genetic and protein levels in neutrophils. The mice appeared healthy and the expression of C5aR1 in bone marrow and blood neutrophils was not negatively affected by LysM-specific deletion of C5aR2. Using the antibody transfer mouse model of EBA, we found that the absence of C5aR2 in LysM-positive cells resulted in an overall amelioration of disease progression, similar to what we had previously found in mice with global deficiency of C5aR2. Neutrophils lacking C5aR2 showed decreased activation after C5a stimulation and increased expression of the inhibitory Fcγ receptor FcγRIIb. Discussion Overall, with the data presented here, we confirm and extend our previous findings and show that C5aR2 in neutrophils regulates their activation and function in response to C5a by potentially affecting the expression of Fcγ receptors and CD11b. Thus, C5aR2 regulates the finely tuned interaction network between immune complexes, Fcγ receptors, CD11b, and C5aR1 that is important for neutrophil recruitment and sustained activation. This underscores the importance of C5aR2 in the pathogenesis of neutrophil-mediated autoimmune diseases.
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Affiliation(s)
- Daniel L. Seiler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Katja H. Kähler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Marie Kleingarn
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Christian D. Sadik
- Center for Research on Inflammation of the Skin (CRIS), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University Hospital Schleswig-Holstein, Lübeck, Germany
| | - Katja Bieber
- Center for Research on Inflammation of the Skin (CRIS), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University Hospital Schleswig-Holstein, Lübeck, Germany
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Centre, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Ralf J. Ludwig
- Center for Research on Inflammation of the Skin (CRIS), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergology and Venerology, University Hospital Schleswig-Holstein, Lübeck, Germany
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Christian M. Karsten
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
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Yu H, Liu Z. GNA12 regulates C5a-induced migration by downregulating C5aR1-PLCβ2-PI3K-AKT-ERK1/2 signaling. BIOPHYSICS REPORTS 2023; 9:33-44. [PMID: 37426201 PMCID: PMC10323775 DOI: 10.52601/bpr.2023.230001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/21/2023] [Indexed: 07/11/2023] Open
Abstract
Gna12 has been identified as one of the reported inflammatory bowel disease (IBD) susceptibility genes in genome-wide association studies (GWAS). However, the function of GNA12 in intestinal homeostasis remains unknown. Here we report that GNA12, a G-protein α subunit, regulates C5a-induced migration in macrophages. Deficiency of GNA12 results in enhanced migration induced by C5a in macrophages. Mechanistically, GNA12 suppresses C5a-induced migration by downregulating the C5aR1-PLCβ2-PI3K-AKT-ERK1/2 signaling. Therefore, our study reveals that GNA12 is an anti-inflammatory factor, which might alleviate the development of inflammation by inhibiting the excessive chemotactic migration of macrophages.
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Affiliation(s)
- Haonan Yu
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhihua Liu
- Key Laboratory of Infection and Immunity, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- Institute for Immunology, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
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7
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Emtenani S, Holtsche MM, Stahlkopf R, Seiler DL, Burn T, Liu H, Parker M, Yilmaz K, Dikmen HO, Lang MH, Sadik CD, Karsten CM, van Beek N, Ludwig RJ, Köhl J, Schmidt E. Differential expression of C5aR1 and C5aR2 in innate and adaptive immune cells located in early skin lesions of bullous pemphigoid patients. Front Immunol 2022; 13:942493. [PMID: 36466856 PMCID: PMC9716273 DOI: 10.3389/fimmu.2022.942493] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 09/05/2022] [Indexed: 10/20/2023] Open
Abstract
Bullous pemphigoid (BP), the by far most frequent autoimmune subepidermal blistering disorder (AIBD), is characterized by the deposition of autoantibodies against BP180 (type XVII collagen; Col17) and BP230 as well as complement components at the dermal-epidermal junction (DEJ). The mechanisms of complement activation in BP patients, including the generation of C5a and regulation of its two cognate C5aRs, i.e., C5aR1 and C5aR2, are incompletely understood. In this study, transcriptome analysis of perilesional and non-lesional skin biopsies of BP patients compared to site-, age-, and sex-matched controls showed an upregulated expression of C5AR1, C5AR2, CR1, and C3AR1 and other complement-associated genes in perilesional BP skin. Of note, increased expressions of C5AR2 and C3AR1 were also observed in non-lesional BP skin. Subsequently, double immunofluorescence (IF) staining revealed T cells and macrophages as the dominant cellular sources of C5aR1 in early lesions of BP patients, while C5aR2 mainly expressed on mast cells and eosinophils. In addition, systemic levels of various complement factors and associated molecules were measured in BP patients and controls. Significantly higher plasma levels of C3a, CD55, and mannose-binding lectin-pathway activity were found in BP patients compared to controls. Finally, the functional relevance of C5aR1 and C5aR2 in BP was explored by two in vitro assays. Specific inhibition of C5aR1, resulted in significantly reduced migration of human neutrophils toward the chemoattractant C5a, whereas stimulation of C5aR2 showed no effect. In contrast, the selective targeting of C5aR1 and/or C5aR2 had no effect on the release of reactive oxygen species (ROS) from Col17-anti-Col17 IgG immune complex-stimulated human leukocytes. Collectively, this study delineates a complex landscape of activated complement receptors, complement factors, and related molecules in early BP skin lesions. Our results corroborate findings in mouse models of pemphigoid diseases that the C5a/C5aR1 axis is pivotal for attracting inflammatory cells to the skin and substantiate our understanding of the C5a/C5aR1 axis in human BP. The broad expression of C5aRs on multiple cell types critical for BP pathogenesis call for clinical studies targeting this axis in BP and other complement-mediated AIBDs.
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Affiliation(s)
- Shirin Emtenani
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Maike M. Holtsche
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany
| | - Richard Stahlkopf
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
| | - Daniel L. Seiler
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Timothy Burn
- Incyte Research Institute, Wilmington, DE, United States
| | - Huiqing Liu
- Incyte Research Institute, Wilmington, DE, United States
| | - Melissa Parker
- Incyte Research Institute, Wilmington, DE, United States
| | - Kaan Yilmaz
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany
| | - Hasan O. Dikmen
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany
| | - Markus Huber Lang
- Institute of Experimental Trauma-Immunology, University Hospital of Ulm, Ulm, Germany
| | - Christian D. Sadik
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany
| | - Christian M. Karsten
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
| | - Nina van Beek
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany
| | - Ralf J. Ludwig
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research (ISEF), University of Lübeck, Lübeck, Germany
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Centre, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Enno Schmidt
- Lübeck Institute of Experimental Dermatology (LIED), University of Lübeck, Lübeck, Germany
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany
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8
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Muldur S, Vadysirisack DD, Ragunathan S, Tang Y, Ricardo A, Sayegh CE, Irimia D. Human Neutrophils Respond to Complement Activation and Inhibition in Microfluidic Devices. Front Immunol 2021; 12:777932. [PMID: 34899737 PMCID: PMC8653703 DOI: 10.3389/fimmu.2021.777932] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 10/29/2021] [Indexed: 12/30/2022] Open
Abstract
Complement activation is key to anti-microbial defenses by directly acting on microbes and indirectly by triggering cellular immune responses. Complement activation may also contribute to the pathogenesis of numerous inflammatory and immunological diseases. Consequently, intense research focuses on developing therapeutics that block pathology-causing complement activation while preserving anti-microbial complement activities. However, the pace of research is slowed down significantly by the limitations of current tools for evaluating complement-targeting therapeutics. Moreover, the effects of potential therapeutic agents on innate immune cells, like neutrophils, are not fully understood. Here, we employ microfluidic assays and measure chemotaxis, phagocytosis, and swarming changes in human neutrophils ex vivo in response to various complement-targeting agents. We show that whereas complement factor 5 (C5) cleavage inhibitor eculizumab blocks all neutrophil anti-microbial functions, newer compounds like the C5 cleavage inhibitor RA101295 and C5a receptor antagonist avacopan inhibit chemotaxis and swarming while preserving neutrophil phagocytosis. These results highlight the utility of microfluidic neutrophil assays in evaluating potential complement-targeting therapeutics.
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Affiliation(s)
- Sinan Muldur
- BioMEMS Resource Center, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.,Shriners Burns Hospital, Boston, MA, United States
| | | | | | - Yalan Tang
- Ra Pharmaceuticals, Inc., Cambridge, MA, United States
| | | | | | - Daniel Irimia
- BioMEMS Resource Center, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.,Shriners Burns Hospital, Boston, MA, United States
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9
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Emerging Role of C5 Complement Pathway in Peripheral Neuropathies: Current Treatments and Future Perspectives. Biomedicines 2021; 9:biomedicines9040399. [PMID: 33917266 PMCID: PMC8067968 DOI: 10.3390/biomedicines9040399] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/12/2022] Open
Abstract
The complement system is a key component of innate immunity since it plays a critical role in inflammation and defense against common pathogens. However, an inappropriate activation of the complement system is involved in numerous disorders, including peripheral neuropathies. Current strategies for neuropathy-related pain fail to achieve adequate pain relief, and although several therapies are used to alleviate symptoms, approved disease-modifying treatments are unavailable. This urgent medical need is driving the development of therapeutic agents for this condition, and special emphasis is given to complement-targeting approaches. Recent evidence has underscored the importance of complement component C5a and its receptor C5aR1 in inflammatory and neuropathic pain, indicating that C5a/C5aR1 axis activation triggers a cascade of events involved in pathophysiology of peripheral neuropathy and painful neuro-inflammatory states. However, the underlying pathophysiological mechanisms of this signaling in peripheral neuropathy are not fully known. Here, we provide an overview of complement pathways and major components associated with dysregulated complement activation in peripheral neuropathy, and of drugs under development targeting the C5 system. C5/C5aR1 axis modulators could represent a new strategy to treat complement-related peripheral neuropathies. Specifically, we describe novel C5aR allosteric modulators, which may potentially become new tools in the therapeutic armory against neuropathic pain.
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10
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Role of C5aR1 and C5L2 Receptors in Ischemia-Reperfusion Injury. J Clin Med 2021; 10:jcm10050974. [PMID: 33801177 PMCID: PMC7957510 DOI: 10.3390/jcm10050974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/12/2021] [Accepted: 02/17/2021] [Indexed: 01/08/2023] Open
Abstract
The role of C5a receptors (C5aR1 and C5L2) in renal ischemia-reperfusion injury (IRI) is uncertain. We generated an in vitro model of hypoxia/reoxygenation with human proximal tubule epithelial cells to mimic some IRI events. C5aR1, membrane attack complex (MAC) and factor H (FH) deposits were evaluated with immunofluorescence. Quantitative polymerase chain reaction evaluated the expression of C5aR1, C5L2 genes as well as genes related to tubular injury, inflammation, and profibrotic pathways. Additionally, C5aR1 and C5L2 deposits were evaluated in kidney graft biopsies (KB) from transplant patients with delayed graft function (DGF, n = 12) and compared with a control group (n = 8). We observed higher immunofluorescence expression of C5aR1, MAC and FH as higher expression of genes related to tubular injury, inflammatory and profibrotic pathways and of C5aR1 in the hypoxic cells; whereas, C5L2 gene expression was unaffected by the hypoxic stimulus. Regarding KB, C5aR1 was detected in the apical and basal membrane of tubular epithelial cells, whereas C5L2 deposits were observed in endothelial cells of peritubular capillaries (PTC). DGF-KB showed more frequently diffuse C5aR1 staining and C5L2 compared to controls. In conclusion, C5aR1 expression is increased by hypoxia and IRI, both in vitro and in human biopsies with an acute injury. C5L2 expression in PTC could be related to endothelial cell damage during IRI.
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11
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Han X, de la Fuente M, Nieman MT. Complement factor C4a does not activate protease-activated receptor 1 (PAR1) or PAR4 on human platelets. Res Pract Thromb Haemost 2021; 5:104-110. [PMID: 33537534 PMCID: PMC7845074 DOI: 10.1002/rth2.12459] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 10/22/2020] [Accepted: 11/04/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Protease-activated receptor (PAR) 1 and PAR4 are key thrombin signal mediators for human platelet activation and aggregation in response to vascular injury. They are primarily activated by thrombin cleavage of the N-terminus to expose a tethered ligand. In addition to the canonical activation by thrombin, a growing panel of proteases can also elicit PAR1- or PAR4-mediated signal transduction. Recently, complement factor C4a was reported as the first endogenous agonist for both PAR1 and PAR4. Further, it is the first endogenous nontethered ligand that activates PAR1 and PAR4. These studies were conducted with human microvascular cells; the impact of C4a on platelet PARs is unknown. OBJECTIVES The goal of this study was to interrogate PAR1 and PAR4 activation by C4a on human platelets. METHODS Platelet-rich plasma (PRP) was isolated from healthy donors. PRP was stimulated with C4a, and the platelet aggregation was measured. Human embryonic kidney (HEK) 293 Flp-In T-rex cells were used to further test if C4a stimulation can initiate PAR1- or PAR4-mediated Gαq signaling, which was measured by intracellular calcium mobilization. RESULTS C4a failed to elicit platelet aggregation via PAR1- or PAR4-mediated manner. In addition, no PAR1- or PAR4-mediated calcium mobilization was observed upon C4a stimulation on HEK293 cells. CONCLUSIONS Complement factor C4a does not activate PAR1 or PAR4 on human platelets. These data show that PAR1 and PAR4 activation by C4a on microvascular cells likely requires a cofactor, which reinforces the concept of cell type-specific regulation of protease signaling.
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Affiliation(s)
- Xu Han
- Department of PharmacologyCase Western Reserve UniversityClevelandOHUSA
| | | | - Marvin T. Nieman
- Department of PharmacologyCase Western Reserve UniversityClevelandOHUSA
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12
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Thomas RC, Kheder R, Alaridhee H, Martin N, Stover CM. Complement Properdin Regulates the Metabolo-Inflammatory Response to a High Fat Diet. ACTA ACUST UNITED AC 2020; 56:medicina56090484. [PMID: 32971872 PMCID: PMC7558790 DOI: 10.3390/medicina56090484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 02/03/2023]
Abstract
Background and objectives: Overnutrition leads to a metabolic and inflammatory response that includes the activation of Complement. Properdin is the only amplifier of complement activation and increases the provision of complement activation products. Its absence has previously been shown to lead to increased obesity in mice on a high fat diet. The aim of this study was to determine ways in which properdin contributes to a less pronounced obese phenotype. Materials and Methods: Wild type (WT) and properdin deficient mice (KO) were fed a high-fat diet (HFD) for up to 12 weeks. Results: There was a significant increase in liver triglyceride content in the KO HFD group compared to WT on HFD. WT developed steatosis. KO had an additional inflammatory component (steatohepatitis). Analysis of AKT signalling by phosphorylation array supported a decrease in insulin sensitivity which was greater for KO than WT in liver and kidney. There was a significant decrease of C5L2 in the fat membranes of the KO HFD group compared to the WT HFD group. Circulating microparticles in KO HFD group showed lower presence of C5L2. Expression of the fatty acid transporter CD36 in adipose tissue was increased in KO on HFD and was also significantly increased in plasma of KO HFD mice compared to WT on HFD. CD36 was elevated on microparticles from KO on HFD. Ultrastructural changes consistent with obesity-associated glomerulopathy were observed for both HFD fed genotypes, but tubular strain was greater in KO. Conclusion: Our work demonstrates that complement properdin is a dominant factor in limiting the severity of obesity-associated conditions that impact on liver and kidney. The two receptors, C5L2 and CD36, are downstream of the activity exerted by properdin.
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Affiliation(s)
- Rόisín C. Thomas
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
| | - Ramiar Kheder
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
| | - Hasanain Alaridhee
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
| | - Naomi Martin
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
- Faculty of Health and Life Sciences, De Montfort University, Leicester LE1 9BH, UK
| | - Cordula M. Stover
- Department of Respiratory Sciences, University of Leicester, Leicester LE1 9HN, UK; (R.C.T.); (R.K.); (H.A.); (N.M.)
- Correspondence: ; Tel.: +44-116-2525032
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13
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Deciphering the Intricate Roles of Radiation Therapy and Complement Activation in Cancer. Int J Radiat Oncol Biol Phys 2020; 108:46-55. [PMID: 32629082 DOI: 10.1016/j.ijrobp.2020.06.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 12/22/2022]
Abstract
The complement system consists of a collection of serum proteins that act as the main frontline effector arm of the innate immune system. Activation of complement can occur through 3 individual induction pathways: the classical, mannose-binding lectin, and alternative pathways. Activation results in opsonization, recruitment of effector cells through potent immune mediators known as anaphylatoxins, and cell lysis via the formation of the membrane attack complex. Stringent regulation of complement is required to protect against inappropriate activation of the complement cascade. Complement activation within the tumor microenvironment does not increase antitumoral action; instead, it enhances tumor growth and disease progression. Radiation therapy (RT) is a staple in the treatment of malignancies and controls tumor growth through direct DNA damage and the influx of immune cells, reshaping the makeup of the tumor microenvironment. The relationship between RT and complement activity in the tumor microenvironment is uncertain at best. The following review will focus on the complex interaction of complement activation and the immune-modulating effects of RT and the overall effect on tumor progression. The clinical implications of complement activation in cancer and the use of therapeutics and potential biomarkers will also be covered.
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14
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Li XX, Clark RJ, Woodruff TM. C5aR2 Activation Broadly Modulates the Signaling and Function of Primary Human Macrophages. THE JOURNAL OF IMMUNOLOGY 2020; 205:1102-1112. [PMID: 32611725 DOI: 10.4049/jimmunol.2000407] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023]
Abstract
The complement activation fragment C5a is a potent proinflammatory mediator that is increasingly recognized as an immune modulator. C5a acts through two C5a receptors, C5aR1 (C5aR, CD88) and C5aR2 (C5L2, GPR77), to powerfully modify multiple aspects of immune cell function. Although C5aR1 is generally acknowledged to be proinflammatory and immune-activating, the potential roles played by C5aR2 remain poorly defined. Despite studies demonstrating C5aR2 can modulate C5aR1 in human cells, it is not yet known whether C5aR2 functionality is limited to, or requires, C5aR1 activation or influences immune cells more broadly. The present study, therefore, aimed to characterize the roles of C5aR2 on the signaling and function of primary human monocyte-derived macrophages, using a C5aR2 agonist (Ac-RHYPYWR-OH; P32) to selectively activate the receptor. We found that although C5aR2 activation with P32 by itself was devoid of any detectable MAPK signaling activities, C5aR2 agonism significantly dampened C5aR1-, C3aR-, and chemokine-like receptor 1 (CMKLR1)-mediated ERK signaling and altered intracellular calcium mobilization mediated by these receptors. Functionally, selective C5aR2 activation also downregulated cytokine production triggered by various TLRs (TLR2, TLR3, TLR4, and TLR7), C-type lectin receptors (Dectin-1, Dectin-2, and Mincle), and the cytosolic DNA sensor stimulator of IFN genes (STING). Surprisingly, activity at the C-type lectin receptors was particularly powerful, with C5aR2 activation reducing Mincle-mediated IL-6 and TNF-α generation by 80-90%. In sum, this study demonstrates that C5aR2 possesses pleiotropic functions in primary human macrophages, highlighting the role of C5aR2 as a powerful regulator of innate immune function.
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Affiliation(s)
- Xaria X Li
- School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Richard J Clark
- School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Trent M Woodruff
- School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
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15
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Zhang T, Wu KY, Ma N, Wei LL, Garstka M, Zhou W, Li K. The C5a/C5aR2 axis promotes renal inflammation and tissue damage. JCI Insight 2020; 5:134081. [PMID: 32191644 DOI: 10.1172/jci.insight.134081] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/11/2020] [Indexed: 12/11/2022] Open
Abstract
C5a is a potent inflammatory mediator that binds C5aR1 and C5aR2. Although pathogenic roles of the C5a/C5aR1 axis in inflammatory disorders are well documented, the roles for the C5a/C5aR2 axis in inflammatory disorders and underlying mechanisms remain unclear. Here, we show that the C5a/C5aR2 axis contributes to renal inflammation and tissue damage in a mouse model of acute pyelonephritis. Compared with WT littermates, C5ar2-/- mice had significantly reduced renal inflammation, tubular damage, and renal bacterial load following bladder inoculation with uropathogenic E. coli. The decrease in inflammatory responses in the kidney of C5ar2-/- mice was correlated with reduced intrarenal levels of high mobility group box-1 protein (HMGB1), NLRP3 inflammasome components, cleaved caspase-1, and IL-1β. In vitro, C5a stimulation of macrophages from C5ar1-/- mice (lacking C5aR1 but expressing C5aR2) led to significant upregulation of HMGB1 release, NLRP3/cleaved caspase-1 inflammasome activation, and IL-1β secretion. Furthermore, blockade of HMGB1 significantly reduced C5a-mediated upregulation of NLRP3/cleaved caspase-1 inflammasome activation and IL-1β secretion in the macrophages, implying a HMGB1-dependent upregulation of NLRP3/cleaved caspase-1 inflammasome activation in macrophages. Our findings demonstrate a pathogenic role for the C5a/C5aR2 axis in renal injury following renal infection and suggest that the C5a/C5aR2 axis contributes to renal inflammation and tissue damage through upregulation of HMGB1 and NLRP3/cleaved caspase-1 inflammasome.
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Affiliation(s)
- Ting Zhang
- Core Research Laboratory, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Kun-Yi Wu
- Core Research Laboratory, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ning Ma
- Core Research Laboratory, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ling-Lin Wei
- Core Research Laboratory, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Malgorzata Garstka
- Core Research Laboratory, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Wuding Zhou
- Peter Gorer Department of Immunobiology, School of Immunology & Microbial Sciences, King's College London, London, United Kingdom
| | - Ke Li
- Core Research Laboratory, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China.,National Local Joint Engineering Research Centre of Biodiagnostics and Biotherapy, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi, China
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16
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Meloni BP, Mastaglia FL, Knuckey NW. Cationic Arginine-Rich Peptides (CARPs): A Novel Class of Neuroprotective Agents With a Multimodal Mechanism of Action. Front Neurol 2020; 11:108. [PMID: 32158425 PMCID: PMC7052017 DOI: 10.3389/fneur.2020.00108] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/30/2020] [Indexed: 12/17/2022] Open
Abstract
There are virtually no clinically available neuroprotective drugs for the treatment of acute and chronic neurological disorders, hence there is an urgent need for the development of new neuroprotective molecules. Cationic arginine-rich peptides (CARPs) are an expanding and relatively novel class of compounds, which possess intrinsic neuroprotective properties. Intriguingly, CARPs possess a combination of biological properties unprecedented for a neuroprotective agent including the ability to traverse cell membranes and enter the CNS, antagonize calcium influx, target mitochondria, stabilize proteins, inhibit proteolytic enzymes, induce pro-survival signaling, scavenge toxic molecules, and reduce oxidative stress as well as, having a range of anti-inflammatory, analgesic, anti-microbial, and anti-cancer actions. CARPs have also been used as carrier molecules for the delivery of other putative neuroprotective agents across the blood-brain barrier and blood-spinal cord barrier. However, there is increasing evidence that the neuroprotective efficacy of many, if not all these other agents delivered using a cationic arginine-rich cell-penetrating peptide (CCPPs) carrier (e.g., TAT) may actually be mediated largely by the properties of the carrier molecule, with overall efficacy further enhanced according to the amino acid composition of the cargo peptide, in particular its arginine content. Therefore, in reviewing the neuroprotective mechanisms of action of CARPs we also consider studies using CCPPs fused to a putative neuroprotective peptide. We review the history of CARPs in neuroprotection and discuss in detail the intrinsic biological properties that may contribute to their cytoprotective effects and their usefulness as a broad-acting class of neuroprotective drugs.
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Affiliation(s)
- Bruno P Meloni
- Department of Neurosurgery, QEII Medical Centre, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Frank L Mastaglia
- Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
| | - Neville W Knuckey
- Department of Neurosurgery, QEII Medical Centre, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.,Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.,Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, WA, Australia
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17
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Muenstermann M, Strobel L, Klos A, Wetsel RA, Woodruff TM, Köhl J, Johswich KO. Distinct roles of the anaphylatoxin receptors C3aR, C5aR1 and C5aR2 in experimental meningococcal infections. Virulence 2019; 10:677-694. [PMID: 31274379 PMCID: PMC6650196 DOI: 10.1080/21505594.2019.1640035] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 04/08/2019] [Accepted: 06/28/2019] [Indexed: 02/08/2023] Open
Abstract
The complement system is pivotal in the defense against invasive disease caused by Neisseria meningitidis (Nme, meningococcus), particularly via the membrane attack complex. Complement activation liberates the anaphylatoxins C3a and C5a, which activate three distinct G-protein coupled receptors, C3aR, C5aR1 and C5aR2 (anaphylatoxin receptors, ATRs). We recently discovered that C5aR1 exacerbates the course of the disease, revealing a downside of complement in Nme sepsis. Here, we compared the roles of all three ATRs during mouse nasal colonization, intraperitoneal infection and human whole blood infection with Nme. Deficiency of complement or ATRs did not alter nasal colonization, but significantly affected invasive disease: Compared to WT mice, the disease was aggravated in C3ar-/- mice, whereas C5ar1-/- and C5ar2-/- mice showed increased resistance to meningococcal sepsis. Surprisingly, deletion of either of the ATRs resulted in lower cytokine/chemokine responses, irrespective of the different susceptibilities of the mice. This was similar in ex vivo human whole blood infection using ATR inhibitors. Neutrophil responses to Nme were reduced in C5ar1-/- mouse blood. Upon stimulation with C5a plus Nme, mouse macrophages displayed reduced phosphorylation of ERK1/2, when C5aR1 or C5aR2 were ablated or inhibited, suggesting that both C5a-receptors prime an initial macrophage response to Nme. Finally, in vivo blockade of C5aR1 alone (PMX205) or along with C5aR2 (A8Δ71-73) resulted in ameliorated disease, whereas neither antagonizing C3aR (SB290157) nor its activation with a "super-agonist" peptide (WWGKKYRASKLGLAR) demonstrated a benefit. Thus, C5aR1 and C5aR2 augment disease pathology and are interesting targets for treatment, whereas C3aR is protective in experimental meningococcal sepsis.
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Affiliation(s)
- Marcel Muenstermann
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany
| | - Lea Strobel
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany
| | - Andreas Klos
- Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Hannover, Germany
| | - Rick A. Wetsel
- Institute of Molecular Medicine Center for Immunology and Autoimmune Diseases, The University of Texas Health Science Center, Houston, TX, USA
| | - Trent M. Woodruff
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
- Division of Immunobiology, Cincinnati Children’s Hospital and University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Kay O. Johswich
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany
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18
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Mueller-Ortiz SL, Shivshankar P, Wetsel RA. The Second Receptor for C5a, C5aR2, Is Detrimental to Mice during Systemic Infection with Listeria monocytogenes. THE JOURNAL OF IMMUNOLOGY 2019; 203:2701-2711. [PMID: 31597707 DOI: 10.4049/jimmunol.1900314] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 09/15/2019] [Indexed: 01/17/2023]
Abstract
Infection with Listeria monocytogenes is acquired through ingestion of contaminated foods and may lead to systemic infection and possible death, with an overall 20% mortality rate. Our previous work using C5aR1-/- mice and C3aR-/- mice demonstrated that C5aR1 and C3aR both play powerful anti-inflammatory and prosurvival roles during systemic infection with L. monocytogenes In our current study, we have examined the role of the third anaphylatoxin receptor, C5aR2, in the host immune response to systemic L. monocytogenes infection. C5aR2-/- mice had significantly lower bacterial burdens in the spleens and livers on both day 1 and 3 postinfection compared with C5aR2+/+ mice. The decreased bacterial burdens in the C5aR2-/- mice correlated with less liver damage and with improved survival of CD4+ and CD8+ T cells in the spleen on day 3 postinfection compared with C5aR2+/+ mice. C5aR2-/- mice also produced significantly less G-CSF, IL-6, and MCP-1 in the serum, spleen, and liver on day 1 postinfection compared with C5aR2+/+ mice. C5aR2-/- and C5aR2+/+ mice produced similar amounts of IFN-γ in their spleens on day 1 postinfection. Purified naive splenocytes from C5aR2-/- mice produced significantly more IFN-γ and IL-12p70 during in vitro infection with L. monocytogenes compared with splenocytes from C5aR2+/+ mice in an NF-κB-dependent manner. Induction of IL-12 and IFN-γ early during infection with L. monocytogenes is protective to the host, and we believe this innate increased ability to produce more IL-12 and IFN-γ provided early protection to the C5aR2-/- mice.
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Affiliation(s)
- Stacey L Mueller-Ortiz
- Brown Foundation Institute of Molecular Medicine, Research Center for Immunology and Autoimmune Diseases, University of Texas Health Science Center at Houston, Houston, TX 77030; and
| | - Pooja Shivshankar
- Brown Foundation Institute of Molecular Medicine, Research Center for Immunology and Autoimmune Diseases, University of Texas Health Science Center at Houston, Houston, TX 77030; and
| | - Rick A Wetsel
- Brown Foundation Institute of Molecular Medicine, Research Center for Immunology and Autoimmune Diseases, University of Texas Health Science Center at Houston, Houston, TX 77030; and .,Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030
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19
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Zhong F, Hu Z, Jiang K, Lei B, Wu Z, Yuan G, Luo H, Dong C, Tang B, Zheng C, Yang S, Zeng Y, Guo Z, Yu S, Su H, Zhang G, Qiu X, Tomlinson S, He S. Complement C3 activation regulates the production of tRNA-derived fragments Gly-tRFs and promotes alcohol-induced liver injury and steatosis. Cell Res 2019; 29:548-561. [PMID: 31076642 PMCID: PMC6796853 DOI: 10.1038/s41422-019-0175-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 04/12/2019] [Indexed: 12/23/2022] Open
Abstract
Complement is known to play a role in alcoholic fatty liver disease (AFLD), but the underlying mechanisms are poorly understood, thereby constraining the development of a rational approach for therapeutic intervention in the complement system. C3 deficiency has been shown to impart protective effects against ethanol-induced hepatic steatosis and inflammation. Here we demonstrate a protection effect in wild-type mice by treatment with CR2-Crry, a specific inhibitor of C3 activation. The expression of glycine transfer (t) RNA-derived fragments (Gly-tRFs) is upregulated in ethanol-fed mice and inhibition of Gly-tRFs in vivo decreases chronic ethanol feeding-induced hepatosteatosis without affecting inflammation. The expression of Gly-tRF was downregulated in C3-deficient or CR2-Crry-treated mice, but not in C5-deficient mice; Gly-tRF expression was restored by the C3 activation products C3a or Asp (C3a-des-Arg) via the regulation of CYP2E1. Transcriptome profiling of hepatic tissues showed that Gly-tRF inhibitors upregulate the expression of sirtuin1 (Sirt1) and subsequently affect downstream lipogenesis and β-oxidation pathways. Mechanistically, Gly-tRF interacts with AGO3 to downregulate Sirt1 expression via sequence complementarity in the 3' UTR. Notably, the expression levels of C3d, CYP2E1 and Gly-tRF are upregulated, whereas Sirt1 is decreased in AFLD patients compared to healthy controls. Collectively, our findings suggest that C3 activation products contribute to hepatosteatosis by regulating the expression of Gly-tRF. Complement inhibition at the C3 activation step and treatment with Gly-tRF inhibitors may be potential and precise therapeutic approaches for AFLD.
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Affiliation(s)
- Fudi Zhong
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zhigao Hu
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
- Laboratory of Liver Injury and Repair, Nanning, Guangxi, China
| | - Keqing Jiang
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Biao Lei
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zhan Wu
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Guandou Yuan
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Hongliang Luo
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Chunqiang Dong
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Bo Tang
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Chaowen Zheng
- Laboratory of Liver Injury and Repair, Nanning, Guangxi, China
| | - Shuai Yang
- Laboratory of Liver Injury and Repair, Nanning, Guangxi, China
| | - Yonglian Zeng
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zhenya Guo
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Shuiping Yu
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Huizhao Su
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Guo Zhang
- Department of Gastroenterology, the People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Xiaoqiang Qiu
- Laboratory of Liver Injury and Repair, Nanning, Guangxi, China
| | - Stephen Tomlinson
- Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC, USA
| | - Songqing He
- Division of Hepatobiliary Surgery, the First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
- Laboratory of Liver Injury and Repair, Nanning, Guangxi, China.
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20
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Ohlsson S, Holm L, Hansson C, Ohlsson SM, Gunnarsson L, Pettersson Å, Skattum L. Neutrophils from ANCA-associated vasculitis patients show an increased capacity to activate the complement system via the alternative pathway after ANCA stimulation. PLoS One 2019; 14:e0218272. [PMID: 31216309 PMCID: PMC6583988 DOI: 10.1371/journal.pone.0218272] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 05/29/2019] [Indexed: 11/18/2022] Open
Abstract
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), including granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), are autoimmune conditions associated with small vessel inflammation. Earlier studies indicate that complement activation via the alternative pathway plays a major role in the pathogenesis. In this study we have investigated if ANCA-activation of neutrophils from AAV patients leads to activation of the alternative complement pathway. C5a-primed neutrophils (PMN) from 10 AAV patients and 10 healthy controls (HC) were stimulated with PMA or IgG purified from PR3-ANCA positive patients (ANCA IgG). The supernatants were analyzed for release of complement proteins and markers of different granules by ELISA, and release of microparticles (MP) by flow cytometry. The ability of the supernatants to activate the alternative complement pathway was determined by incubation with normal serum and C3bBbP and C5a were measured by ELISA. MP were analyzed by flow cytometry and removed by centrifugation. The supernatants from the AAV patients’ neutrophils produced significantly more C3bBbP compared with HCs (p = 0.0001). C3bBbP levels correlated with the number of MP. After removal of MP from the supernatants, alternative pathway activation was significantly lower. This study shows that primed and ANCA-stimulated neutrophils from AAV patients have a greater ability to activate the alternative complement pathway compared to primed neutrophils from healthy controls. This finding emphasizes the role of complement in the pathogenesis of AAV - underlining the therapeutic potential of C5a and other complement blockade.
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Affiliation(s)
- Sophie Ohlsson
- Department of Nephrology, Institution of Clinical Sciences in Lund, Lund University, Lund, Sweden
- * E-mail:
| | - Lisa Holm
- Department of Nephrology, Institution of Clinical Sciences in Lund, Lund University, Lund, Sweden
| | - Christina Hansson
- Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden
- Clinical Immunology and Transfusion Medicine, Region Skåne, Lund, Sweden
| | - Susanne M. Ohlsson
- Department of Nephrology, Institution of Clinical Sciences in Lund, Lund University, Lund, Sweden
| | - Lena Gunnarsson
- Department of Nephrology, Institution of Clinical Sciences in Lund, Lund University, Lund, Sweden
| | - Åsa Pettersson
- Department of Nephrology, Institution of Clinical Sciences in Lund, Lund University, Lund, Sweden
| | - Lillemor Skattum
- Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden
- Clinical Immunology and Transfusion Medicine, Region Skåne, Lund, Sweden
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21
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Yu S, Wang D, Huang L, Zhang Y, Luo R, Adah D, Tang Y, Zhao K, Lu B. The complement receptor C5aR2 promotes protein kinase R expression and contributes to NLRP3 inflammasome activation and HMGB1 release from macrophages. J Biol Chem 2019; 294:8384-8394. [PMID: 30971430 DOI: 10.1074/jbc.ra118.006508] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 03/31/2019] [Indexed: 01/21/2023] Open
Abstract
The NLR family pyrin domain-containing 3 (NLRP3) inflammasome is a multimeric protein complex that mediates maturation of the cytokines IL-1β and IL-18 as well as release of the proinflammatory protein high-mobility group box 1 (HMGB1) and contributes to several inflammatory diseases, including sepsis, gout, and type 2 diabetes. In this context, the well-studied active complement fragment C5a and its receptor C5aR1 or C5aR2 orchestrate the inflammatory responses in many diseases. Although a C5a-C5aR interaction in NLRP3-associated diseases has been suggested, little is known about the details of C5a-C5aR cross-talk with the NLRP3 inflammasome in macrophages. In this study, using mice and murine macrophages and cytokines, immunoblotting, siRNA, and quantitative real-time PCR assays, we demonstrate that C5aR2 deficiency restricts activation of the NLRP3 inflammasome and release of HMGB1 both in vitro and in vivo Mechanistically, we found that C5aR2 promotes NLRP3 activation by amplifying dsRNA-dependent PKR expression, which is an important NLRP3-activating factor. We also observed that elevation of PKR expression because of the C5a-C5aR2 interaction depends on the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase pathway and type I IFN signaling. In conclusion, these findings reveal that C5aR2 contributes to NLRP3 inflammasome activation and HMGB1 release from macrophages.
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Affiliation(s)
- Songlin Yu
- Department of Hematology and Key Laboratory of Non-resolving Inflammation and Cancer of Hunan Province, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China; Postdoctoral Research Station of Clinical Medicine, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Dan Wang
- Department of Hematology and Key Laboratory of Non-resolving Inflammation and Cancer of Hunan Province, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Lingmin Huang
- Department of Hematology and Key Laboratory of Non-resolving Inflammation and Cancer of Hunan Province, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Yening Zhang
- Department of Hematology and Key Laboratory of Non-resolving Inflammation and Cancer of Hunan Province, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Ruiheng Luo
- Department of Hematology and Key Laboratory of Non-resolving Inflammation and Cancer of Hunan Province, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China
| | - Dickson Adah
- Laboratory of Pathogen Biology, State Key Laboratory of Respiratory Disease, Center for Infection and Immunity, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, Guangdong 510632, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiting Tang
- Department of Physiology, School of Basic Medical Science, Central South University, Changsha, Hunan 410000, China
| | - Kai Zhao
- Department of Hematology and Key Laboratory of Non-resolving Inflammation and Cancer of Hunan Province, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
| | - Ben Lu
- Department of Hematology and Key Laboratory of Non-resolving Inflammation and Cancer of Hunan Province, Third Xiangya Hospital, Central South University, Changsha, Hunan 410000, China; Key Laboratory of Medical Genetics, School of Biological Science and Technology, Central South University, Changsha, Hunan 410000, China; Key Laboratory of Sepsis and Translational Medicine, School of Basic Medical Science, Central South University, Changsha, Hunan 410000, China; Department of Pathophysiology, School of Basic Medical Science, Jinan University, Guangzhou, Guangdong 510632, China.
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22
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Ma Y, Liu Y, Zhang Z, Yang GY. Significance of Complement System in Ischemic Stroke: A Comprehensive Review. Aging Dis 2019; 10:429-462. [PMID: 31011487 PMCID: PMC6457046 DOI: 10.14336/ad.2019.0119] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/19/2019] [Indexed: 12/14/2022] Open
Abstract
The complement system is an essential part of innate immunity, typically conferring protection via eliminating pathogens and accumulating debris. However, the defensive function of the complement system can exacerbate immune, inflammatory, and degenerative responses in various pathological conditions. Cumulative evidence indicates that the complement system plays a critical role in the pathogenesis of ischemic brain injury, as the depletion of certain complement components or the inhibition of complement activation could reduce ischemic brain injury. Although multiple candidates modulating or inhibiting complement activation show massive potential for the treatment of ischemic stroke, the clinical availability of complement inhibitors remains limited. The complement system is also involved in neural plasticity and neurogenesis during cerebral ischemia. Thus, unexpected side effects could be induced if the systemic complement system is inhibited. In this review, we highlighted the recent concepts and discoveries of the roles of different kinds of complement components, such as C3a, C5a, and their receptors, in both normal brain physiology and the pathophysiology of brain ischemia. In addition, we comprehensively reviewed the current development of complement-targeted therapy for ischemic stroke and discussed the challenges of bringing these therapies into the clinic. The design of future experiments was also discussed to better characterize the role of complement in both tissue injury and recovery after cerebral ischemia. More studies are needed to elucidate the molecular and cellular mechanisms of how complement components exert their functions in different stages of ischemic stroke to optimize the intervention of targeting the complement system.
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Affiliation(s)
- Yuanyuan Ma
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yanqun Liu
- 3Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zhijun Zhang
- 2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Yuan Yang
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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23
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Bröker K, Terzenbach R, Bentzien F, Lüth S, Dammermann W. Complement factors C3a and C5a mimick a proinflammatory microenvironment and increase HBV IGRA sensitivity. J Transl Med 2019; 17:6. [PMID: 30602374 PMCID: PMC6317231 DOI: 10.1186/s12967-018-1752-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 12/21/2018] [Indexed: 12/13/2022] Open
Abstract
Background Hepatitis B virus (HBV) infections represent a global health problem and chronic hepatitis B (CHB) leads to liver cirrhosis and hepatocellular carcinoma. Thus, timely diagnosis of hepatitis B is crucial to ensure adequate treatment. We developed a powerful and rapid whole blood-based cytokine release assay assessing cellular immune responses to HBV antigens. IL-2 and IFNγ release in this assay depicts hepatitis B vaccination status. Of note, CHB goes along with elevated C5a concentrations in plasma. We aim at mimicking the proinflammatory microenvironment associated with HBV infection to enhance the diagnostic quality of our HBV specific cytokine release assay. We specifically investigated the potential of the complement factors C3a and C5a as costimulators and analyzed their potential effects on activation marker expression on T cells and antigen presenting cells. Results Whole blood from 87 healthy individuals (n = 59 hepatitis B vaccinated, n = 28 unvaccinated) was stimulated with HBV surface antigen (HBsAg) in presence or absence of C3a or C5a, respectively. Further, C3a and C5a were used in combination to investigate potential synergistic effects. IL-2 and IFNγ levels in plasma were quantified using ELISA. Complement factor C5a specifically enhances HBsAg-mediated IL-2 (690.3 ± 195.4 pg/ml vs. 789.4 ± 216.5 pg/ml) and IFNγ (146.0 ± 43.1 pg/ml vs. 336.7 ± 67.9 pg/ml) responses in whole blood. Similar cytokine levels were measured when both C3a and C5a were used. With a diagnostic specificity of 90% the IFNγ release assay reached a diagnostic sensitivity of 49.2% upon whole blood stimulation with HBsAg alone, but of 78.9% when HBsAg was combined with C3a and C5a. Conclusions Innate signals mediated via complement pathways contribute to HBV-specific cellular immune responses. The massively improved diagnostic sensitivity of the IFNγ release assay after addition of C3a and C5a demonstrates that these effects render whole blood-based cytokine release assays even more potent as screening tools in HBV immunology and HBV vaccination studies. Electronic supplementary material The online version of this article (10.1186/s12967-018-1752-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Katharina Bröker
- Center of Internal Medicine II, Brandenburg Medical School, University Hospital Brandenburg, Hochstrasse 29, 14770, Brandenburg, Germany.,Department of Anatomy and Experimental Morphology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Robin Terzenbach
- Center of Internal Medicine II, Brandenburg Medical School, University Hospital Brandenburg, Hochstrasse 29, 14770, Brandenburg, Germany.,Department of Anatomy and Experimental Morphology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Frank Bentzien
- Department of Transfusion Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Stefan Lüth
- Center of Internal Medicine II, Brandenburg Medical School, University Hospital Brandenburg, Hochstrasse 29, 14770, Brandenburg, Germany
| | - Werner Dammermann
- Center of Internal Medicine II, Brandenburg Medical School, University Hospital Brandenburg, Hochstrasse 29, 14770, Brandenburg, Germany. .,Department of Anatomy and Experimental Morphology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
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24
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Nissilä E, Hakala P, Leskinen K, Roig A, Syed S, Van Kessel KPM, Metso J, De Haas CJC, Saavalainen P, Meri S, Chroni A, Van Strijp JAG, Öörni K, Jauhiainen M, Jokiranta TS, Haapasalo K. Complement Factor H and Apolipoprotein E Participate in Regulation of Inflammation in THP-1 Macrophages. Front Immunol 2018; 9:2701. [PMID: 30519244 PMCID: PMC6260146 DOI: 10.3389/fimmu.2018.02701] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/01/2018] [Indexed: 12/28/2022] Open
Abstract
The alternative pathway (AP) of complement is constantly active in plasma and can easily be activated on self surfaces and trigger local inflammation. Host cells are protected from AP attack by Factor H (FH), the main AP regulator in plasma. Although complement is known to play a role in atherosclerosis, the mechanisms of its contribution are not fully understood. Since FH via its domains 5-7 binds apoliporotein E (apoE) and macrophages produce apoE we examined how FH could be involved in the antiatherogenic effects of apoE. We used blood peripheral monocytes and THP-1 monocyte/macrophage cells which were also loaded with acetylated low-density lipoprotein (LDL) to form foam cells. Binding of FH and apoE on these cells was analyzed by flow cytometry. High-density lipoprotein (HDL)-mediated cholesterol efflux of activated THP-1 cells was measured and transcriptomes of THP-1 cells using mRNA sequencing were determined. We found that binding of FH to human blood monocytes and cholesterol-loaded THP-1 macrophages increased apoE binding to these cells. Preincubation of fluorescent cholesterol labeled THP-1 macrophages in the presence of FH increased cholesterol efflux and cholesterol-loaded macrophages displayed reduced transcription of proinflammatory/proatherogenic factors and increased transcription of anti-inflammatory/anti-atherogenic factors. Further incubation of THP-1 cells with serum reduced C3b/iC3b deposition. Overall, our data indicate that apoE and FH interact with monocytic cells in a concerted action and this interaction reduces complement activation and inflammation in the atherosclerotic lesions. By this way FH may participate in mediating the beneficial effects of apoE in suppressing atherosclerotic lesion progression.
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Affiliation(s)
- Eija Nissilä
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Pipsa Hakala
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Katarzyna Leskinen
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Angela Roig
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Shahan Syed
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | | | - Jari Metso
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Carla J. C. De Haas
- Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Päivi Saavalainen
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Athens, Greece
| | | | | | - Matti Jauhiainen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - T. Sakari Jokiranta
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
| | - Karita Haapasalo
- Department of Bacteriology and Immunology, and Research Programs Unit, Immunobiology, University of Helsinki, Helsinki, Finland
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25
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Michailidou I, Jongejan A, Vreijling JP, Georgakopoulou T, de Wissel MB, Wolterman RA, Ruizendaal P, Klar-Mohamad N, Grootemaat AE, Picavet DI, Kumar V, van Kooten C, Woodruff TM, Morgan BP, van der Wel NN, Ramaglia V, Fluiter K, Baas F. Systemic inhibition of the membrane attack complex impedes neuroinflammation in chronic relapsing experimental autoimmune encephalomyelitis. Acta Neuropathol Commun 2018; 6:36. [PMID: 29724241 PMCID: PMC5932802 DOI: 10.1186/s40478-018-0536-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 04/16/2018] [Indexed: 12/31/2022] Open
Abstract
The complement system is a key driver of neuroinflammation. Activation of complement by all pathways, results in the formation of the anaphylatoxin C5a and the membrane attack complex (MAC). Both initiate pro-inflammatory responses which can contribute to neurological disease. In this study, we delineate the specific roles of C5a receptor signaling and MAC formation during the progression of experimental autoimmune encephalomyelitis (EAE)-mediated neuroinflammation. MAC inhibition was achieved by subcutaneous administration of an antisense oligonucleotide specifically targeting murine C6 mRNA (5 mg/kg). The C5a receptor 1 (C5aR1) was inhibited with the C5a receptor antagonist PMX205 (1.5 mg/kg). Both treatments were administered systemically and started after disease onset, at the symptomatic phase when lymphocytes are activated. We found that antisense-mediated knockdown of C6 expression outside the central nervous system prevented relapse of disease by impeding the activation of parenchymal neuroinflammatory responses, including the Nod-like receptor protein 3 (NLRP3) inflammasome. Furthermore, C6 antisense-mediated MAC inhibition protected from relapse-induced axonal and synaptic damage. In contrast, inhibition of C5aR1-mediated inflammation diminished expression of major pro-inflammatory mediators, but unlike C6 inhibition, it did not stop progression of neurological disability completely. Our study suggests that MAC is a key driver of neuroinflammation in this model, thereby MAC inhibition might be a relevant treatment for chronic neuroinflammatory diseases.
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26
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Complement 5a Receptor deficiency does not influence adverse cardiac remodeling after pressure-overload in mice. Sci Rep 2017; 7:17045. [PMID: 29213128 PMCID: PMC5719022 DOI: 10.1038/s41598-017-16957-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/20/2017] [Indexed: 02/07/2023] Open
Abstract
Hypertension is one of the most common risk factors for the development heart failure in the general population. Inflammation plays a central role in this adverse remodeling and eventually to the development of heart failure. Circulating levels of Complement factor 5a (C5a) are increased in hypertensive patients and the C5a receptor is associated with the presence of cardiac fibrosis and inflammation in an experimental hypertension model. To test if C5aR is involved in adverse cardiac remodeling following pressure-overload, we induced transverse aortic constriction (TAC) in wildtype and C5a receptor deficient mice (C5aR-/-). Six weeks after TAC, C5aR-/- animals showed a similar degree of cardiac hypertrophy and decrease in cardiac function as wild type mice (End Systolic Volume; 50.30±5.32 µl vs. 55.81±8.16 µl). In addition, other features of adverse cardiac remodeling like cardiomyocyte cell size (WGA staining), fibrosis (picrosirius red staining) or collagen degradation (matrix metalloproteinase activity assay) did not differ either. In conclusion, full body C5aR deficiency does not affect adverse cardiac remodeling after pressure-overload. However, our finding are in contrast with C5a inhibition studies. Our observations do present the role of C5a-C5aR in adverse cardiac remodeling and heart failure as controversial at the least.
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27
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Corrigendum to "The Controversial C5a Receptor C5aR2: Its Role in Health and Disease". J Immunol Res 2017; 2017:6073961. [PMID: 29226158 PMCID: PMC5687145 DOI: 10.1155/2017/6073961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 10/16/2017] [Indexed: 12/03/2022] Open
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