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Rezvani R, Shadmand Foumani Moghadam MR, Cianflone K. Acylation stimulating protein/C3adesArg in the metabolic states: role of adipocyte dysfunction in obesity complications. J Physiol 2024; 602:773-790. [PMID: 38305477 DOI: 10.1113/jp285127] [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: 07/21/2023] [Accepted: 11/27/2023] [Indexed: 02/03/2024] Open
Abstract
Adipose tissue, as an endocrine organ, secretes several adipocyte-derived hormones named 'adipokines' that are implicated in regulating energy haemostasis. Substantial evidence shows that white adipose tissue-derived adipokines mediate the link between obesity-related exogenous factors (like diet and lifestyle) and various biological events (such as pre- and postmenopausal status) that have obesity consequences (cardiometabolic disorders). One of the critical aetiological factors for obesity-related diseases is the dysfunction of adipokine pathways. Acylation-stimulating protein (ASP) is an adipokine that stimulates triglyceride synthesis and storage in adipose tissue by enhancing glucose and fatty acid uptake. ASP acts via its receptor C5L2. The primary objective of this review is to address the existing gap in the literature regarding ASP by investigating its diverse responses and receptor interactions across multiple determinants of obesity. These determinants include diet composition, metabolic disorders, organ involvement, sex and sex hormone levels. Furthermore, this article explores the broader paradigm shift from solely focusing on adipose tissue mass, which contributes to obesity, to considering the broader implications of adipose tissue function. Additionally, we raise a critical question concerning the clinical relevance of the insights gained from this review, both in terms of potential therapeutic interventions targeting ASP and in the context of preventing obesity-related conditions, highlighting the potential of the ASP-C5L2 interaction as a pharmacological target. In conclusion, these findings validate that obesity is a low-grade inflammatory status with multiorgan involvement and sex differences, demonstrating dynamic interactions between immune and metabolic response determinants.
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Affiliation(s)
- Reza Rezvani
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Katherine Cianflone
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
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2
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Trambas IA, Coughlan MT, Tan SM. Therapeutic Potential of Targeting Complement C5a Receptors in Diabetic Kidney Disease. Int J Mol Sci 2023; 24:ijms24108758. [PMID: 37240105 DOI: 10.3390/ijms24108758] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/26/2023] [Accepted: 04/28/2023] [Indexed: 05/28/2023] Open
Abstract
Diabetic kidney disease (DKD) affects 30-40% of patients with diabetes and is currently the leading cause of end-stage renal disease (ESRD). The activation of the complement cascade, a highly conserved element of the innate immune system, has been implicated in the pathogenesis of diabetes and its complications. The potent anaphylatoxin C5a is a critical effector of complement-mediated inflammation. Excessive activation of the C5a-signalling axis promotes a potent inflammatory environment and is associated with mitochondrial dysfunction, inflammasome activation, and the production of reactive oxygen species. Conventional renoprotective agents used in the treatment of diabetes do not target the complement system. Mounting preclinical evidence indicates that inhibition of the complement system may prove protective in DKD by reducing inflammation and fibrosis. Targeting the C5a-receptor signaling axis is of particular interest, as inhibition at this level attenuates inflammation while preserving the critical immunological defense functions of the complement system. In this review, the important role of the C5a/C5a-receptor axis in the pathogenesis of diabetes and kidney injuries will be discussed, and an overview of the status and mechanisms of action of current complement therapeutics in development will be provided.
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Affiliation(s)
- Inez A Trambas
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
| | - Melinda T Coughlan
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
| | - Sih Min Tan
- Department of Diabetes, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
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3
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Ghosh M, Rana S. The anaphylatoxin C5a: Structure, function, signaling, physiology, disease, and therapeutics. Int Immunopharmacol 2023; 118:110081. [PMID: 36989901 DOI: 10.1016/j.intimp.2023.110081] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023]
Abstract
The complement system is one of the oldest known tightly regulated host defense systems evolved for efficiently functioning cell-based immune systems and antibodies. Essentially, the complement system acts as a pivot between the innate and adaptive arms of the immune system. The complement system collectively represents a cocktail of ∼50 cell-bound/soluble glycoproteins directly involved in controlling infection and inflammation. Activation of the complement cascade generates complement fragments like C3a, C4a, and C5a as anaphylatoxins. C5a is the most potent proinflammatory anaphylatoxin, which is involved in inflammatory signaling in a myriad of tissues. This review provides a comprehensive overview of human C5a in the context of its structure and signaling under several pathophysiological conditions, including the current and future therapeutic applications targeting C5a.
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Affiliation(s)
- Manaswini Ghosh
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 752050, India
| | - Soumendra Rana
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha 752050, India.
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4
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Zetoune FS, Ward PA. THE IMMUNOPATHOGENESIS OF POLYMICROBIAL SEPSIS. Shock 2023; 59:311-317. [PMID: 36377404 PMCID: PMC9957923 DOI: 10.1097/shk.0000000000002049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
ABSTRACT This report deals with the advances made in the areas of complement and its role in sepsis, both in mice and in humans. The study relates to work over the past 25 years (late 1990s to October 2022). During this period, there has been very rapid progress in understanding the activation pathways of complement and the activation products of complement, especially the anaphylatoxin C5a and its receptors, C5aR1 and C5aR2. Much has also been learned about these pathways of activation that trigger activation of the innate immune system and the array of strong proinflammatory cytokines that can cause cell and organ dysfunction, as well as complement products that cause immunosuppression. The work in septic humans and mice, along with patients who develop lung dysfunction caused by COVID-19, has taught us that there are many strategies for treatment of humans who are septic or develop COVID-19-related lung dysfunction. To date, treatments in humans with these disorders suggest that we are in the midst of a new and exciting area related to the complement system.
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Affiliation(s)
- Firas S. Zetoune
- University of Michigan Medical School, Department of Pathology, Ann Arbor, MI 48109
| | - Peter A. Ward
- University of Michigan Medical School, Department of Pathology, Ann Arbor, MI 48109
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Das A, Gupta PK, Rana S. C5aR2 receptor: The genomic twin of the flamboyant C5aR1. J Cell Biochem 2022; 123:1841-1856. [PMID: 35977039 DOI: 10.1002/jcb.30320] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/05/2022] [Indexed: 11/12/2022]
Abstract
The complement fragment C5a is one of the most potent proinflammatory glycoproteins liberated by the activation of the biochemical cascade of the complement system. C5a is established to interact with a set of genomically related transmembrane receptors, like C5aR1 (CD88, C5aR) and C5aR2 (GPR77, C5L2) with comparable affinity. The C5aR1 is a classical G-protein-coupled receptor (GPCR), whereas C5aR2 is a nonclassical GPCR that tailors immune cell activity potentially through β-arrestins rather than G-proteins. Currently, the exact function of the C5aR2 is actively debated in the context of C5aR1, even though both C5aR1 and C5aR2 are coexpressed on myriads of tissues. The functional relevance of C5aR2 appears to be context-dependent compared to the C5aR1, which has received enormous attention for its role in both acute and chronic inflammatory diseases. In addition, the structure of C5aR2 and its interaction specificity toward C5a is not structurally elucidated in the literature so far. The current study has attempted to close the gap by generating highly refined model structures of C5aR2, respectively in free (inactive), complexed to C-terminal peptide of C5a (meta-active) and the C5a (active), embedded to a model palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer. The computational modeling and the 1.5-μs molecular dynamics data presented in the current study are expected to further enrich the understanding of C5a-C5aR2 interaction compared to C5a-C5aR1, which will surely help in elaborating the currently debated biological function of C5aR2 better in the foreseeable future.
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Affiliation(s)
- Aurosikha Das
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, Bhubaneswar, India
| | - Pulkit K Gupta
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, Bhubaneswar, India
| | - Soumendra Rana
- Chemical Biology Laboratory, School of Basic Sciences, Indian Institute of Technology Bhubaneswar, Odisha, Bhubaneswar, India
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6
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Jiang Y, Chen Y, Sun H, Zhang X, He L, Li J, Zhao G, Sun S. MERS-CoV infection causes brain damage in human DPP4-transgenic mice through complement-mediated inflammation. J Gen Virol 2021; 102. [PMID: 34704923 PMCID: PMC8604193 DOI: 10.1099/jgv.0.001667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The highly pathogenic Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a severe respiratory virus. Recent reports indicate additional central nervous system (CNS) involvement. In this study, human DPP4 transgenic mice were infected with MERS-CoV, and viral antigens were first detected in the midbrain-hindbrain 4 days post-infection, suggesting the virus may enter the brainstem via peripheral nerves. Neurons and astrocytes throughout the brain were infected, followed by damage of the blood brain barrier (BBB), as well as microglial activation and inflammatory cell infiltration, which may be caused by complement activation based on the observation of deposition of complement activation product C3 and high expression of C3a receptor (C3aR) and C5a receptor (C5aR1) in neurons and glial cells. It may be concluded that these effects were mediated by complement activation in the brain, because of their reduction resulted from the treatment with mouse C5aR1-specific mAb. Such mAb significantly reduced nucleoprotein expression, suppressed microglial activation and decreased activation of caspase-3 in neurons and p38 phosphorylation in the brain. Collectively, these results suggest that MERS-CoV infection of CNS triggers complement activation, leading to inflammation-mediated damage of brain tissue, and regulating of complement activation could be a promising intervention and adjunctive treatment for CNS injury by MERS-CoV and other coronaviruses.
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Affiliation(s)
- Yuting Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Yuehong Chen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Hong Sun
- Department of Basic Medical Sciences, North China University of Science and Technology, Tangshan 063210, PR China
| | - Xiaolu Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Lei He
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Jiangfan Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Guangyu Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
| | - Shihui Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China
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7
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Mannes M, Schmidt CQ, Nilsson B, Ekdahl KN, Huber-Lang M. Complement as driver of systemic inflammation and organ failure in trauma, burn, and sepsis. Semin Immunopathol 2021; 43:773-788. [PMID: 34191093 PMCID: PMC8243057 DOI: 10.1007/s00281-021-00872-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/23/2021] [Indexed: 02/08/2023]
Abstract
Complement is one of the most ancient defense systems. It gets strongly activated immediately after acute injuries like trauma, burn, or sepsis and helps to initiate regeneration. However, uncontrolled complement activation contributes to disease progression instead of supporting healing. Such effects are perceptible not only at the site of injury but also systemically, leading to systemic activation of other intravascular cascade systems eventually causing dysfunction of several vital organs. Understanding the complement pathomechanism and its interplay with other systems is a strict requirement for exploring novel therapeutic intervention routes. Ex vivo models exploring the cross-talk with other systems are rather limited, which complicates the determination of the exact pathophysiological roles that complement has in trauma, burn, and sepsis. Literature reporting on these three conditions is often controversial regarding the importance, distribution, and temporal occurrence of complement activation products further hampering the deduction of defined pathophysiological pathways driven by complement. Nevertheless, many in vitro experiments and animal models have shown beneficial effects of complement inhibition at different levels of the cascade. In the future, not only inhibition but also a complement reconstitution therapy should be considered in prospective studies to expedite how meaningful complement-targeted interventions need to be tailored to prevent complement augmented multi-organ failure after trauma, burn, and sepsis. This review summarizes clinically relevant studies investigating the role of complement in the acute diseases trauma, burn, and sepsis with important implications for clinical translation.
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Affiliation(s)
- Marco Mannes
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Helmholtzstr. 8/2, 89081, Ulm, Germany
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Bo Nilsson
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden
| | - Kristina N Ekdahl
- Department of Immunology, Genetics and Pathology (IGP), Rudbeck Laboratory C5:3, Uppsala University, Uppsala, Sweden.,Linnaeus Center of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Markus Huber-Lang
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital of Ulm, Helmholtzstr. 8/2, 89081, Ulm, Germany.
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8
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Local complement factor H protects kidney endothelial cell structure and function. Kidney Int 2021; 100:824-836. [PMID: 34139209 DOI: 10.1016/j.kint.2021.05.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 05/09/2021] [Accepted: 05/20/2021] [Indexed: 12/25/2022]
Abstract
Factor H (FH) is a critical regulator of the alternative complement pathway and its deficiency or mutation underlie kidney diseases such as dense deposit disease. Since vascular dysfunction is an important facet of kidney disease, maintaining optimal function of the lining endothelial cells is important for vascular health. To investigate the molecular mechanisms that are regulated by FH in endothelial cells, FH deficient and sufficient mouse kidney endothelial cell cultures were established. Endothelial FH deficiency resulted in cytoskeletal remodeling, increased angiogenic potential, loss of cellular layer integrity and increased cell proliferation. FH reconstitution prevented these FH-dependent proliferative changes. Respiratory flux analysis showed reduced basal mitochondrial respiration, ATP production and maximal respiratory capacity in FH deficient endothelial cells, while proton leak remained unaltered. Similar changes were observed in FH deficient human glomerular endothelial cells indicating the translational potential of these studies. Gene expression analysis revealed that the FH-dependent gene changes in mouse kidney endothelial cells include significant upregulation of genes involved in inflammation and the complement system. The transcription factor nuclear factor-kB, that regulates many biological processes, was translocated from the cytoplasm to the nucleus in the absence of FH. Thus, our studies show the functional relevance of intrinsic FH in kidney endothelial cells in man and mouse.
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9
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Sommerfeld O, Medyukhina A, Neugebauer S, Ghait M, Ulferts S, Lupp A, König R, Wetzker R, Schulz S, Figge MT, Bauer M, Press AT. Targeting Complement C5a Receptor 1 for the Treatment of Immunosuppression in Sepsis. Mol Ther 2021; 29:338-346. [PMID: 32966769 PMCID: PMC7791006 DOI: 10.1016/j.ymthe.2020.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 03/25/2020] [Accepted: 09/01/2020] [Indexed: 12/18/2022] Open
Abstract
Complement factor C5a was originally identified as a powerful promoter of inflammation through activation of the C5a receptor 1 (C5ar1). Recent evidence suggests involvement of C5a not only in pro- but also in anti-inflammatory signaling. The present study aims to unveil the role of C5ar1 as potential therapeutic target in a murine sepsis model. Our study discloses a significantly increased survival in models of mild to moderate but not severe sepsis of C5ar1-deficient mice. The decreased mortality of C5ar1-deficient mice is accompanied by improved pathogen clearance and largely preserved liver function. C5ar1-deficient mice exhibited a significantly increased production of the pro-inflammatory mediator interferon-γ (IFN-γ) and a decreased production of the anti-inflammatory cytokine interleukin-10 (IL-10). Together, these data uncover C5a signaling as a mediator of immunosuppressive processes during sepsis and describe the C5ar1 and related changes of the IFN-γ to IL-10 ratio as markers for the immunological (dys)function accompanying sepsis.
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Affiliation(s)
- Oliver Sommerfeld
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
| | - Anna Medyukhina
- Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany
| | - Sophie Neugebauer
- Institute of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, Jena, Germany
| | - Mohamed Ghait
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
| | - Svenja Ulferts
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
| | - Amelie Lupp
- Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany
| | - Rainer König
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany; Network Modeling, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute Jena, Jena, Germany
| | - Reinhard Wetzker
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Stefan Schulz
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany; Institute of Pharmacology and Toxicology, Jena University Hospital, Jena, Germany
| | - Marc Thilo Figge
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany; Applied Systems Biology, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute (HKI), Jena, Germany; Institute of Microbiology, Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
| | - Michael Bauer
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
| | - Adrian T Press
- Department of Anesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany.
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10
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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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11
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Li XX, Lee JD, Kemper C, Woodruff TM. The Complement Receptor C5aR2: A Powerful Modulator of Innate and Adaptive Immunity. THE JOURNAL OF IMMUNOLOGY 2020; 202:3339-3348. [PMID: 31160390 DOI: 10.4049/jimmunol.1900371] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/07/2019] [Indexed: 01/01/2023]
Abstract
Complement activation generates the core effector protein C5a, a potent immune molecule that is linked to multiple inflammatory diseases. Two C5a receptors, C5aR1 (C5aR, CD88) and C5aR2 (C5L2, GPR77), mediate the biological activities of C5a. Although C5aR1 has broadly acknowledged proinflammatory roles, C5aR2 remains at the center of controversy, with existing findings supporting both immune-activating and immune-dampening functions. Recent progress has been made toward resolving these issues. Instead of being a pure recycler and sequester of C5a, C5aR2 is capable of mediating its own set of signaling events and through these events exerting significant immunomodulatory effects not only toward C5aR1 but also other pattern recognition receptors and innate immune systems, such as NLRP3 inflammasomes. This review highlights the existing knowns and unknowns concerning C5aR2 and provides a timely update on recent breakthroughs which are expected to have a substantial impact on future fundamental and translational C5aR2 research.
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Affiliation(s)
- Xaria X Li
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia; and
| | - John D Lee
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia; and
| | - Claudia Kemper
- National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Trent M Woodruff
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia; and
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12
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Nabizadeh JA, Manthey HD, Panagides N, Steyn FJ, Lee JD, Li XX, Akhir FNM, Chen W, Boyle GM, Taylor SM, Woodruff TM, Rolfe BE. C5a receptors C5aR1 and C5aR2 mediate opposing pathologies in a mouse model of melanoma. FASEB J 2019; 33:11060-11071. [PMID: 31298935 DOI: 10.1096/fj.201800980rr] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The canonical complement component 5a (C5a) receptor (C5aR) 1 has well-described roles in tumorigenesis but the contribution of the second receptor, C5aR2, is unclear. The present study demonstrates that B16.F0 melanoma cells express mRNA for both C5aR1 and C5aR2 and signal through ERK and p38 MAPKs in response to C5a. Despite this, C5a had no impact on melanoma cell proliferation or migration in vitro. In vivo studies demonstrated that the growth of B16.F0 melanoma tumors was increased in C5aR2-/- mice but reduced in C5aR1-/- mice and wild-type mice treated with a C5aR1 antagonist. Analysis of tumor-infiltrating leukocyte populations showed no significant differences between wild-type and C5aR2-/- mice. Conversely, percentages of myeloid-derived suppressor cells, macrophages, and regulatory T lymphocytes were lower in tumors from C5aR1-/- mice, whereas total (CD3+) T lymphocytes and CD4+ subsets were higher. Analysis of cytokine and chemokine levels also showed plasma IFN-γ was higher and tumor C-C motif chemokine ligand 2 was lower in the absence of C5aR1. The results suggest that C5aR1 signaling supports melanoma growth by promoting infiltration of immunosuppressive leukocyte populations into the tumor microenvironment, whereas C5aR2 has a more restricted but beneficial role in limiting tumor growth. Overall, these data support the potential of C5aR1-inhibitory therapies for melanoma.-Nabizadeh, J. A., Manthey, H. D., Panagides, N., Steyn, F. J., Lee, J. D., Li, X. X., Akhir, F. N. M., Chen, W., Boyle, G. M., Taylor, S. M., Woodruff, T. M., Rolfe, B. E. C5a receptors C5aR1 and C5aR2 mediate opposing pathologies in a mouse model of melanoma.
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Affiliation(s)
- Jamileh A Nabizadeh
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Helga D Manthey
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Nadya Panagides
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Frederik J Steyn
- Centre for Clinical Research, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - John D Lee
- School of Biomedical Science, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Xaria X Li
- School of Biomedical Science, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Fazrena N M Akhir
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Weiyu Chen
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Glen M Boyle
- Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Herston, Brisbane, Queensland, Australia
| | - Stephen M Taylor
- School of Biomedical Science, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Trent M Woodruff
- School of Biomedical Science, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
| | - Barbara E Rolfe
- Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, Brisbane, Queensland, Australia
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13
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Jiang Y, Li J, Teng Y, Sun H, Tian G, He L, Li P, Chen Y, Guo Y, Li J, Zhao G, Zhou Y, Sun S. Complement Receptor C5aR1 Inhibition Reduces Pyroptosis in hDPP4-Transgenic Mice Infected with MERS-CoV. Viruses 2019; 11:v11010039. [PMID: 30634407 PMCID: PMC6356766 DOI: 10.3390/v11010039] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/27/2018] [Accepted: 01/02/2019] [Indexed: 02/07/2023] Open
Abstract
Middle East respiratory syndrome coronavirus (MERS-CoV) is a highly pathogenic virus with a crude mortality rate of ~35%. Previously, we established a human DPP4 transgenic (hDPP4-Tg) mouse model in which we studied complement overactivation-induced immunopathogenesis. Here, to better understand the pathogenesis of MERS-CoV, we studied the role of pyroptosis in THP-1 cells and hDPP4 Tg mice with MERS-CoV infection. We found that MERS-CoV infection induced pyroptosis and over-activation of complement in human macrophages. The hDPP4-Tg mice infected with MERS-CoV overexpressed caspase-1 in the spleen and showed high IL-1β levels in serum, suggesting that pyroptosis occurred after infection. However, when the C5a-C5aR1 axis was blocked by an anti-C5aR1 antibody (Ab), expression of caspase-1 and IL-1β fell. These data indicate that MERS-CoV infection induces overactivation of complement, which may contribute to pyroptosis and inflammation. Pyroptosis and inflammation were suppressed by inhibiting C5aR1. These results will further our understanding of the pathogenesis of MERS-CoV infection.
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Affiliation(s)
- Yuting Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Junfeng Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Yue Teng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Hong Sun
- Department of Basic Medical Sciences, North China University of Science and Technology, Tangshan 063210, China.
| | - Guang Tian
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Lei He
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Pei Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Yuehong Chen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Yan Guo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Jiangfan Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Guangyu Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
| | - Yusen Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
- Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450052, China.
| | - Shihui Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
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14
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Jackson TC, Dixon CE, Janesko-Feldman K, Vagni V, Kotermanski SE, Jackson EK, Kochanek PM. Acute Physiology and Neurologic Outcomes after Brain Injury in SCOP/PHLPP1 KO Mice. Sci Rep 2018; 8:7158. [PMID: 29739983 PMCID: PMC5940799 DOI: 10.1038/s41598-018-25371-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/20/2018] [Indexed: 11/12/2022] Open
Abstract
Suprachiasmatic nucleus circadian oscillatory protein (SCOP) (a.k.a. PHLPP1) regulates long-term memory consolidation in the brain. Using a mouse model of controlled cortical impact (CCI) we tested if (1) brain tissue levels of SCOP/PHLPP1 increase after a traumatic brain injury (TBI), and (2) if SCOP/PHLPP1 gene knockout (KO) mice have improved (or worse) neurologic outcomes. Blood chemistry (pH, pCO2, pO2, pSO2, base excess, sodium bicarbonate, and osmolarity) and arterial pressure (MAP) differed in isoflurane anesthetized WT vs. KOs at baseline and up to 1 h post-injury. CCI injury increased cortical/hippocampal SCOP/PHLPP1 levels in WTs 7d and 14d post-injury. Injured KOs had higher brain tissue levels of phosphorylated AKT (pAKT) in cortex (14d post-injury), and higher levels of phosphorylated MEK (pMEK) in hippocampus (7d and 14d post-injury) and in cortex (7d post-injury). Consistent with an important role of SCOP/PHLPP1 on memory function, injured-KOs had near normal performance on the probe trial of the Morris water maze, whereas injured-WTs were impaired. CA1/CA3 hippocampal survival was lower in KOs vs. WTs 24 h post-injury but equivalent by 7d. No difference in 21d cortical lesion volume was detected. SCOP/PHLPP1 overexpression in cultured rat cortical neurons had no effect on 24 h cell death after a mechanical stretch-injury.
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Affiliation(s)
- Travis C Jackson
- University of Pittsburgh School of Medicine, Safar Center for Resuscitation Research, Children's Hospital of Pittsburgh of UPMC, John G. Rangos Research Center - 6th Floor 4401 Penn Avenue, Pittsburgh, PA, 15224, USA. .,University of Pittsburgh School of Medicine, Department of Critical Care Medicine, Scaife Hall, 3550 Terrace Street, Pittsburgh, USA.
| | - C Edward Dixon
- University of Pittsburgh School of Medicine, Safar Center for Resuscitation Research, Children's Hospital of Pittsburgh of UPMC, John G. Rangos Research Center - 6th Floor 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.,University of Pittsburgh School of Medicine, Department of Neurology, 811 Kaufmann Medical Building, 3471 Fifth Avenue, Pittsburgh, USA
| | - Keri Janesko-Feldman
- University of Pittsburgh School of Medicine, Safar Center for Resuscitation Research, Children's Hospital of Pittsburgh of UPMC, John G. Rangos Research Center - 6th Floor 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.,University of Pittsburgh School of Medicine, Department of Critical Care Medicine, Scaife Hall, 3550 Terrace Street, Pittsburgh, USA
| | - Vincent Vagni
- University of Pittsburgh School of Medicine, Safar Center for Resuscitation Research, Children's Hospital of Pittsburgh of UPMC, John G. Rangos Research Center - 6th Floor 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.,University of Pittsburgh School of Medicine, Department of Critical Care Medicine, Scaife Hall, 3550 Terrace Street, Pittsburgh, USA
| | - Shawn E Kotermanski
- University of Pittsburgh School of Medicine, Department of Pharmacology and Chemical Biology, Bridgeside Point Building 1, 100 Technology Drive, Pittsburgh, USA
| | - Edwin K Jackson
- University of Pittsburgh School of Medicine, Department of Pharmacology and Chemical Biology, Bridgeside Point Building 1, 100 Technology Drive, Pittsburgh, USA
| | - Patrick M Kochanek
- University of Pittsburgh School of Medicine, Safar Center for Resuscitation Research, Children's Hospital of Pittsburgh of UPMC, John G. Rangos Research Center - 6th Floor 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.,University of Pittsburgh School of Medicine, Department of Critical Care Medicine, Scaife Hall, 3550 Terrace Street, Pittsburgh, USA
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15
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Zhang XY, Liu Y, He T, Yang TT, Wu J, Cianflone K, Lu HL. Anaphylatoxin C5a induces inflammation and reduces insulin sensitivity by activating TLR4/NF-kB/PI3K signaling pathway in 3T3-L1 adipocytes. Biomed Pharmacother 2018; 103:955-964. [PMID: 29710512 DOI: 10.1016/j.biopha.2018.04.057] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 04/07/2018] [Accepted: 04/09/2018] [Indexed: 01/17/2023] Open
Abstract
Obesity closely correlates with metaflammation and characterizes with systemic-chronic-low inflammation. This study aims to evaluate effects of C5a on the inflammatory response and insulin resistance in 3T3-L1 adipocytes. 3T3-L1 pre-adipocytes were induced to the mature 3T3-L1 adipocytes. Then, 3T3-L1 were intervened with anaphylatoxin C5a, lipopolysaccharide (LPS) and C5a + LPS, respectively. Levels of Omentin, Chemerin, Vaspin and Apelin 12 in supernatants of medium were examined using ELISA. C5L2, C5a receptor (C5aR), I kappa B (IkB), IkB kinase (IKK), insulin receptor substrate 1 (IRS-1), IRS-2, PI3 K, p-PI3 K and β-actin were examined using RT-PCR and western blot assay, respectively. C5L2-C5aR colocalization was identified using immunofluorescence double label. NF-kB expression or activity was evaluated using electrophoretic mobility shift assay (EMSA), dual luciferase assay and immunofluorescence assay, respectively. The glucose uptake and insulin sensitivity were also evaluated. Results showed that C5a intervention significantly enhanced inflammatory molecule levels in supernatants of 3T3-L1 adipocytes. IKK inflammatory signaling pathway participated in C5a induced inflammation of 3T3-L1 adipocytes. C5a triggered the colocalization of C5L2 and C5aR and activated the NF-kB inflammatory signaling pathway. C5a intervention in 3T3-L1 adipocytes decreased the glucose uptake and resulted in reduction of insulin sensitivity. Insulin signaling pathway participated in C5a caused insulin sensitivity reduction. C5a intervention triggered the phosphorylation of PI3 K. In conclusion anaphylatoxin C5a induced inflammatory response by activating TLR4/NF-kB signaling pathway and generating C5L2-C5aR dimer, and caused insulin sensitivity reduction by activating PI3 K signaling pathway.
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Affiliation(s)
- Xin-Yan Zhang
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Yan Liu
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Ting He
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Ting-Ting Yang
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China
| | - Jing Wu
- Department of Pediatrics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Katherine Cianflone
- K. Cianflone. Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, QC, G1V4G5, Canada
| | - Hui-Ling Lu
- Department of Pediatrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, China.
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16
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Reichhardt MP, Meri S. Intracellular complement activation-An alarm raising mechanism? Semin Immunol 2018; 38:54-62. [PMID: 29631809 DOI: 10.1016/j.smim.2018.03.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 03/26/2018] [Indexed: 12/20/2022]
Abstract
It has become increasingly apparent that the complement system, being an ancient defense mechanism, is not operative only in the extracellular milieu but also intracellularly. In addition to the known synthetic machinery in the liver and by macrophages, many other cell types, including lymphocytes, adipocytes and epithelial cells produce selected complement components. Activation of e.g. C3 and C5 inside cells may have multiple effects ranging from direct antimicrobial defense to cell differentiation and possible influence on metabolism. Intracellular activation of C3 and C5 in T cells is involved in the maintenance of immunological tolerance and promotes differentiation of T helper cells into Th1-type cells that activate cell-mediated immune responses. Adipocytes are unique in producing many complement sensor proteins (like C1q) and Factor D (adipsin), the key enzyme in promoting alternative pathway amplification. The effects of complement activation products are mediated by intracellular and cell membrane receptors, like C3aR, C5aR1, C5aR2 and the complement regulator MCP/CD46, often jointly with other receptors like the T cell receptor, Toll-like receptors and those of the inflammasomes. These recent observations link complement activation to cellular metabolic processes, intracellular defense reactions and to diverse adaptive immune responses. The complement components may thus be viewed as intracellular alarm molecules involved in the cellular danger response.
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Affiliation(s)
- M P Reichhardt
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom.
| | - S Meri
- Department of Bacteriology and Immunology, Haartman Institute, Immunobiology Research Program, University of Helsinki, Helsinki, Finland; Helsinki University Central Hospital Laboratory (HUSLAB), Helsinki, Finland.
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17
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Association of C5L2 genetic polymorphisms with coronary artery disease in a Han population in Xinjiang, China. Oncotarget 2018; 8:8590-8596. [PMID: 28052000 PMCID: PMC5352424 DOI: 10.18632/oncotarget.14353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 11/30/2016] [Indexed: 01/16/2023] Open
Abstract
Background C5aR-like receptor 2 (C5L2) has been identified as a receptor for the inflammatory factor Complement 5a (C5a) and acylation-stimulating protein (ASP). ASP binding to C5L2 leading to a net accumulation of TG stores and glucose transporter. The aim of the present study is to evaluate the association of the SNPs of C5L2 gene with coronary artery disease (CAD) in a Chinese population. Methods We examined the role of the tagging single nucleotide polymorphisms (SNPs) of C5L2 gene for CAD using a case-control design. We determined the prevalence of C5L2 genotypes in 505 CAD patients and 469 age and sex-matched healthy control subjects of Han population. Results There was significant difference in genotype distributions of rs2972607 and rs8112962 between CAD patients and control subjects. The rs2972607 was found to be associated with CAD in a dominant model (AA vs. AG + GG, P<0.001). Similarly, the rs8112962 was found to be associated with CAD in a dominant model (TT vs CT + CC, P=0.016). The difference remained statistically significant after multivariate adjustment (OR =1.401, 95% confidence interval [CI]:1.026~1.914, P=0.034; OR = 1.541, 95%CI:1.093~ 2.172, P=0.014; respectively). Conclusion The results of this study indicate that both rs2972607 and rs8112962 of C5L2 gene are associated with CAD in a Han population of China.
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18
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Abstract
B-1 cells constitute a unique subpopulation of lymphocytes residing mainly in body cavities like the peritoneal cavity (PerC) but are also found in spleen and bone marrow (BM). As innate-like B cells, they mediate first line immune defense through low-affinity natural IgM (nIgM) antibodies. PerC B-1 cells can egress to the spleen and differentiate into nIgM antibody-secreting plasma cells that recognize conserved exogenous and endogenous cellular structures. Homing to and homeostasis within the PerC are regulated by the chemokine CXCL13 released by PerC macrophages and stroma cells. However, the exact mechanisms underlying the regulation of CXCL13 and B-1 homeostasis are not fully explored. B-1 cells play important roles in the inflammatory response to infection, autoimmunity, ischemia/reperfusion injury, obesity, and atherosclerosis. Remarkably, this list of inflammatory entities has a strong overlap with diseases that are regulated by complement suggesting a link between B-1 cells and the complement system. Interestingly, up to now, no data exist regarding the role of complement in B-1 cell biology. Here, we demonstrate for the first time that C5a regulates B-1 cell steady-state dynamics within the peritoneum, the spleen, and the BM. We found decreased B-1a cell numbers in the peritoneum and the spleen of C5aR1−/− mice associated with increased B1-a and B1-b numbers in the spleen and high serum titers of nIgM antibodies directed against phosphorylcholine and several pneumococcal polysaccharides. Similarly, peritoneal B-1a cells were decreased in the peritoneum and splenic B-1a and B-1b cells were increased in C5aR2−/− mice. The decrease in peritoneal B-1 cell numbers was associated with decreased peritoneal CXCL13 levels in C5aR1−/− and C5aR2−/− mice. In search for mechanisms, we found that combined TLR2 and IL-10 receptor activation in PerC macrophages induced strong CXCL13 production, which was significantly reduced in cells from C5aR1- and C5aR2-deficient mice and after combined C5aR-targeting. Such stimulation also induced marked local C5 production by PerC macrophages and C5a generation. Importantly, peritoneal in vivo administration of C5a increased CXCL13 production. Taken together, our findings suggest that local non-canonical C5 activation in PerC macrophages fuels CXCL13 production as a novel mechanism to control B-1 cell homeostasis.
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Affiliation(s)
- Katharina Bröker
- Brandenburg Medical School, University Hospital Brandenburg, Center of Internal Medicine II, Brandenburg a. d. Havel, Germany
| | - Julia Figge
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Albert F Magnusen
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Rudolf A Manz
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Christian M Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
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19
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A Verghese D, Demir M, Chun N, Fribourg M, Cravedi P, Llaudo I, Woodruff TM, Yadav P, Lira SA, Medof ME, Heeger PS. T Cell Expression of C5a Receptor 2 Augments Murine Regulatory T Cell (T REG) Generation and T REG-Dependent Cardiac Allograft Survival. THE JOURNAL OF IMMUNOLOGY 2018; 200:2186-2198. [PMID: 29436411 DOI: 10.4049/jimmunol.1701638] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/11/2018] [Indexed: 12/26/2022]
Abstract
C5aR2 (C5L2/gp77) is a seven-transmembrane spanning receptor that binds to C5a but lacks motifs essential for G protein coupling and associated signal transduction. C5aR2 is expressed on immune cells, modulates various inflammatory diseases in mice, and has been shown to facilitate murine and human regulatory T cell (TREG) generation in vitro. Whether and how C5aR2 impacts in vivo TREG generation and pathogenic T cell-dependent disease models have not been established. In this article, we show that murine T cells express and upregulate C5aR2 during induced TREG (iTREG) generation and that the absence of T cell-expressed C5aR2 limits in vivo iTREG generation following adoptive transfer of naive CD4+ T cells into Rag1-/- recipients. Using newly generated C5aR2-transgenic mice, we show that overexpression of C5aR2 in naive CD4+ T cells augments in vivo iTREG generation. In a model of TREG-dependent cardiac allograft survival, recipient C5aR2 deficiency accelerates graft rejection associated with lower TREG/effector T cell ratios, whereas overexpression of C5aR2 in immune cells prolongs graft survival associated with an increase in TREG/effector T cell ratios. T cell-expressed C5aR2 modulates TREG induction without altering effector T cell proliferation or cytokine production. Distinct from reported findings in neutrophils and macrophages, TREG-expressed C5aR2 does not interact with β-arrestin or inhibit ERK1/2 signaling. Rather, cumulative evidence supports the conclusion that C5aR2 limits C5aR1-initiated signals known to inhibit TREG induction. Together, the data expand the role of C5aR2 in adaptive immunity by providing in vivo evidence that T cell-expressed C5aR2 physiologically modulates iTREG generation and iTREG-dependent allograft survival.
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Affiliation(s)
- Divya A Verghese
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Markus Demir
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Nicholas Chun
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Miguel Fribourg
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Paolo Cravedi
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Ines Llaudo
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Trent M Woodruff
- School of Biomedical Sciences, The University of Queensland, Brisbane St. Lucia, Brisbane, Queensland 4072, Australia; and
| | - Pragya Yadav
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Sergio A Lira
- Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - M Edward Medof
- Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106
| | - Peter S Heeger
- Nephrology Division, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029; .,Translational Transplant Research Center, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
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20
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Complement receptors C5aR1 and C5aR2 act differentially during the early immune response after bone fracture but are similarly involved in bone repair. Sci Rep 2017; 7:14061. [PMID: 29070810 PMCID: PMC5656620 DOI: 10.1038/s41598-017-14444-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/10/2017] [Indexed: 12/31/2022] Open
Abstract
Severely injured patients frequently suffer compromised fracture healing because of systemic post-traumatic inflammation. An important trigger of the posttraumatic immune response is the complement anaphylatoxin C5a, which acts via two receptors, C5aR1 and C5aR2, expressed on immune and bone cells. The blockade of C5a-mediated inflammation during the early inflammatory phase was demonstrated to improve fracture healing after severe injury. However, the distinct roles of the two complement receptors C5aR1 and C5aR2 in bone has to date not been studied. Here, we investigated bone turnover and regeneration in mice lacking either C5aR1 or C5aR2 in a model of isolated fracture and after severe injury, combining the fracture with an additional thoracic trauma. Both C5aR1−/− and C5aR2−/− mice displayed an increased bone mass compared to wild-type controls due to reduced osteoclast formation and increased osteoblast numbers, respectively. Following fracture, the inflammatory response was differently affected in these strains: It was decreased in C5aR1−/− mice but enhanced in C5aR2−/− mice. Both strains exhibited impaired fracture healing, disturbed osteoclastogenesis and delayed cartilage-to-bone transformation. Thus, our data suggest that C5aR1 and C5aR2 differentially regulate the immune response after fracture and are required for effective cartilage-to-bone transformation in the fracture callus and for undisturbed bone healing.
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21
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Laumonnier Y, Wiese AV, Figge J, Karsten C. Regulation and function of anaphylatoxins and their receptors in allergic asthma. Mol Immunol 2017; 84:51-56. [PMID: 27916272 DOI: 10.1016/j.molimm.2016.11.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/18/2016] [Indexed: 02/08/2023]
Abstract
Allergic asthma is a disease of the airways driven by maladaptive T helper 2 (Th2) and Th17 immune response against harmless, airborne substances. The hallmarks of this disease are airway hyperresponsiveness (AHR), eosinophilic and neutrophilic airway inflammation and mucus overproduction. Distinct dendric cell (DC) subsets together with airway epithelial and pulmonary vascular endothelial cells play critical roles in allergen sensing and in driving T cell differentiation towards Th2 and Th17 effector or regulatory T cells (Treg). Previous studies suggested already a pivotal role for the anaphylatoxins (C5a, C3a) in the pathogenesis of allergic asthma. During sensitization for example it is described, that C3a promotes, whereas C5a protects from the development of maladaptive immunity during allergen sensitization. Here we will discuss the role of the anaphylatoxins (C3a, C5a) and their receptors during the pathogenesis of allergic asthma, and specifically in lung DC biology. We will also have a look on canonical and non-canonical complement activation and we will discuss novel concepts on how the adaptive immune system can regulate the function of ATRs also in the context of allergic asthma.
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Affiliation(s)
- Yves Laumonnier
- Institute for Systemic Inflammation Research, University of Lübeck, 23562 Lübeck, Germany.
| | - Anna V Wiese
- Institute for Systemic Inflammation Research, University of Lübeck, 23562 Lübeck, Germany
| | - Julia Figge
- Institute for Systemic Inflammation Research, University of Lübeck, 23562 Lübeck, Germany
| | - Christian Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, 23562 Lübeck, Germany.
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22
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Karsten CM, Wiese AV, Mey F, Figge J, Woodruff TM, Reuter T, Scurtu O, Kordowski A, Almeida LN, Briukhovetska D, Quell KM, Sun J, Ender F, Schmudde I, Vollbrandt T, Laumonnier Y, Köhl J. Monitoring C5aR2 Expression Using a Floxed tdTomato-C5aR2 Knock-In Mouse. THE JOURNAL OF IMMUNOLOGY 2017; 199:3234-3248. [PMID: 28864475 DOI: 10.4049/jimmunol.1700710] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/10/2017] [Indexed: 12/23/2022]
Abstract
The biological significance of C5a receptor [(C5aR)2/C5L2], a seven-transmembrane receptor binding C5a and C5adesArg, remains ill-defined. Specific ligation of C5aR2 inhibits C5a-induced ERK1/2 activation, strengthening the view that C5aR2 regulates C5aR1-mediated effector functions. Although C5aR2 and C5aR1 are often coexpressed, a detailed picture of C5aR2 expression in murine cells and tissues is still lacking. To close this gap, we generated a floxed tandem dye (td)Tomato-C5aR2 knock-in mouse that we used to track C5aR2 expression in tissue-residing and circulating immune cells. We found the strongest C5aR2 expression in the brain, bone marrow, and airways. All myeloid-derived cells expressed C5aR2, although with different intensities. C5aR2 expression in blood and tissue neutrophils was strong and homogeneous. Specific ligation of C5aR2 in neutrophils from tdTomato-C5aR2 mice blocked C5a-driven ERK1/2 phosphorylation, demonstrating functionality of C5aR2 in the reporter mice. In contrast to neutrophils, we found tissue-specific differences in C5aR2 expression in eosinophils, macrophages, and dendritic cell subsets. Naive and activated T cells stained negative for C5aR2, whereas B cells from different tissues homogeneously expressed C5aR2. Also, NK cell subsets in blood and spleen strongly expressed C5aR2. Activation of C5aR2 in NK cells suppressed IL-12/IL-18-induced IFN-γ production. Intratracheal IL-33 challenge resulted in decreased C5aR2 expression in pulmonary eosinophils and monocyte-derived dendritic cells. In summary, we provide a detailed map of murine C5aR2 immune cell expression in different tissues under steady-state conditions and upon pulmonary inflammation. The C5aR2 knock-in mouse will help to reliably track and conditionally delete C5aR2 expression in experimental models of inflammation.
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Affiliation(s)
- Christian M Karsten
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany;
| | - Anna V Wiese
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Fabian Mey
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Julia Figge
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Trent M Woodruff
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Tom Reuter
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Olga Scurtu
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Anna Kordowski
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Larissa N Almeida
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Daria Briukhovetska
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Katharina M Quell
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Jing Sun
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Fanny Ender
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Inken Schmudde
- Institute of Anatomy, University of Lübeck, Lübeck 23562, Germany
| | - Tillman Vollbrandt
- Cell Analysis Core Facility, University of Lübeck, Lübeck 23562, Germany; and
| | - Yves Laumonnier
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, Lübeck 23562, Germany; .,Division of Immunobiology, Cincinnati Children's Hospital and College of Medicine, University of Cincinnati, Cincinnati, OH 45229
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23
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Xu R, Lin F, Bao C, Wang FS. Mechanism of C5a-induced immunologic derangement in sepsis. Cell Mol Immunol 2017; 14:792-793. [PMID: 28782758 PMCID: PMC5596250 DOI: 10.1038/cmi.2017.68] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 11/09/2022] Open
Affiliation(s)
- Ruonan Xu
- Treatment and Research Centre for Infectious Disease, Beijing 100039, China
| | - Fang Lin
- The Institute of Intensive Care Unit, Beijing 100039, China
| | - Chunmei Bao
- The Institute of Clinical Examination Centre, Beijing 100039, China
| | - Fu-Sheng Wang
- Treatment and Research Centre for Infectious Disease, Beijing 100039, China
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24
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Hajishengallis G, Lambris JD. More than complementing Tolls: complement-Toll-like receptor synergy and crosstalk in innate immunity and inflammation. Immunol Rev 2017; 274:233-244. [PMID: 27782328 DOI: 10.1111/imr.12467] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Complement and Toll-like receptors (TLRs) play key roles in the host immune response and are swiftly activated by infection or other types of immunological stress. This review focuses on the capacity of complement and TLRs to engage in signaling crosstalk, ostensibly to coordinate immune and inflammatory responses through synergistic or antagonistic (regulatory) interactions. However, overactivation or dysregulation of either system may lead-often synergistically-to exaggerated inflammation and host tissue injury. Intriguingly, moreover, certain pathogens can manipulate complement-TLR crosstalk pathways in ways that undermine host immunity and favor their persistence. In the setting of polymicrobial inflammatory disease, subversion of complement-TLR crosstalk by keystone pathogens can promote dysbiosis. Knowledge of the molecular mechanisms underlying complement-TLR crosstalk pathways can, therefore, be used productively for tailored therapeutic approaches, such as, to enhance host immunity, mitigate destructive inflammation, or counteract microbial subversion of the host response.
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Affiliation(s)
- George Hajishengallis
- Department of Microbiology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA.
| | - John D Lambris
- Perelman School of Medicine, Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
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25
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Wang R, Lu B, Gerard C, Gerard NP. C5L2, the Second C5a Anaphylatoxin Receptor, Suppresses LPS-Induced Acute Lung Injury. Am J Respir Cell Mol Biol 2017; 55:657-666. [PMID: 27285858 DOI: 10.1165/rcmb.2016-0067oc] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
LPS-induced lung injury in the mouse is one of the most robust experimental models used for studies of acute lung injury (ALI) and acute respiratory distress syndrome in humans. Prior clinical and experimental studies support an important role for complement activation, particularly production of C5a, in the pathophysiology of human ALI/acute respiratory distress syndrome. In the mouse model, however, the precise role of C5a and its receptors is unclear. C5L2, an enigmatic second receptor for C5a, has been characterized, and results have generated substantial debate regarding its in vivo function. Our previous work with human neutrophils revealed a unique role for C5L2 in negatively modulating C5a-C5a receptor (C5aR)-mediated cellular activation, in which antibody-mediated blockade of C5L2 resulted in augmented C5a-C5aR responses. Here, we demonstrate that C5L2-/- mice (BALB/c background) administered intranasal LPS exhibit significantly more airway edema and hemorrhage than do wild-type animals. Bronchoalveolar lavage fluid and lung homogenates have significantly more neutrophils and myeloperoxidase activity, as well as proinflammatory cytokines and chemokines. When a blocking antibody against the C5aR was administered before LPS administration, the increased neutrophilic infiltration and cytokine levels were reversed. Thus, our data show not only that C5a contributes significantly to LPS-induced ALI in the mouse, but also that C5L2 plays an important antiinflammatory role in this model through actions resulting at least in part from negative modulation of C5a receptor activation.
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Affiliation(s)
- Ruobing Wang
- 1 Division of Respiratory Diseases, Boston Children's Hospital, Boston, Massachusetts.,2 Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
| | - Bao Lu
- 1 Division of Respiratory Diseases, Boston Children's Hospital, Boston, Massachusetts
| | - Craig Gerard
- 1 Division of Respiratory Diseases, Boston Children's Hospital, Boston, Massachusetts.,2 Department of Medicine, Harvard Medical School, Boston, Massachusetts; and
| | - Norma P Gerard
- 1 Division of Respiratory Diseases, Boston Children's Hospital, Boston, Massachusetts.,2 Department of Medicine, Harvard Medical School, Boston, Massachusetts; and.,3 Beth Israel Deaconess Medical Center, Boston, Massachusetts
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26
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The Controversial C5a Receptor C5aR2: Its Role in Health and Disease. J Immunol Res 2017; 2017:8193932. [PMID: 28706957 PMCID: PMC5494583 DOI: 10.1155/2017/8193932] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/11/2017] [Indexed: 01/24/2023] Open
Abstract
After the discovery of the C5a receptor C5aR1, C5aR2 is the second receptor found to bind C5a and its des-arginine form. As a heptahelical G protein-coupled receptor but devoid of the intracellular Gα signal, C5aR2 is special and confusing. Ramifications and controversies about C5aR2 are under debate since its identification, from putative ligands and cellular localization to intracellular signals and pathological roles in inflammation and immunity. The ruleless and even conflicting pro- or anti-inflammatory role of C5aR2 in animal models of diverse diseases makes one bewildered. This review summarizes reports on C5aR2, tries to clear up available evidence on these four controversial aspects, and delineates C5aR2 function(s). It also summarizes available toolboxes for C5aR2 study.
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27
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Novel insights into the expression pattern of anaphylatoxin receptors in mice and men. Mol Immunol 2017; 89:44-58. [PMID: 28600003 DOI: 10.1016/j.molimm.2017.05.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 05/22/2017] [Accepted: 05/23/2017] [Indexed: 02/06/2023]
Abstract
The anaphylatoxins (AT) C3a and C5a play important roles as mediators of inflammation. Further, they regulate and control multiple innate and adaptive immune responses through binding and activation of their cognate G protein-coupled receptors, i.e. C3a receptor (C3aR), C5a receptor 1 (C5aR1) and C5a receptor 2 (C5aR2), although the latter lacks important sequence motifs for G protein-coupling. Based on their pleiotropic functions, they contribute not only to tissue homeostasis but drive, perpetuate and resolve immune responses in many inflammatory diseases including infections, malignancies, autoimmune as well as allergic diseases. During the past few years, transcriptome expression data provided detailed insights into AT receptor tissue mRNA expression. In contrast, our understanding of cellular AT receptor expression in human and mouse tissues under steady and inflammatory conditions is still sketchy. Ligand binding studies, flow cytometric and immunohistochemical analyses convincingly demonstrated tissue-specific C5aR1 expression in various cells of myeloid origin. However, a detailed map for C3aR or C5aR2 expression in human or mouse tissue cells is still lacking. Also, reports about AT expression in lymphoid cells is still controversial. To understand the multiple roles of the ATs in the innate and adaptive immune networks, a detailed understanding of their receptor expression in health and disease is required. Recent findings obtained with novel GFP or tdTomato AT-receptor knock-in mice provide detailed insights into their expression pattern in tissue immune and stroma cells. Here, we will provide an update about our current knowledge of AT receptor expression pattern in humans and mice.
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28
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Complement in ANCA-associated vasculitis: mechanisms and implications for management. Nat Rev Nephrol 2017; 13:359-367. [PMID: 28316335 DOI: 10.1038/nrneph.2017.37] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of potentially life-threatening autoimmune diseases. The main histological feature in the kidneys of patients with AAV is pauci-immune necrotizing crescentic glomerulonephritis with little immunoglobulin and complement deposition in the glomerular capillary walls. The complement system was not, therefore, initially thought to be associated with the development of AAV. Accumulating evidence from animal models and clinical observations indicate, however, that activation of the complement system - and the alternative pathway in particular - is crucial for the development of AAV, and that the complement activation product C5a has a central role. Stimulation of neutrophils with C5a and ANCA not only results in the neutrophil respiratory burst and degranulation, but also activates the coagulation system and generates thrombin, thus bridging the inflammation and coagulation systems. In this Review, we provide an overview of the clinical, in vivo and in vitro evidence for a role of complement activation in the development of AAV and discuss how targeting the complement system could provide opportunities for therapy.
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29
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Discovery of functionally selective C5aR2 ligands: novel modulators of C5a signalling. Immunol Cell Biol 2016; 94:787-95. [PMID: 27108698 DOI: 10.1038/icb.2016.43] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 04/19/2016] [Accepted: 04/20/2016] [Indexed: 12/22/2022]
Abstract
The complement cascade is comprised of a highly sophisticated network of innate immune proteins that are activated in response to invading pathogens or tissue injury. The complement activation peptide, C5a, binds two seven transmembrane receptors, namely the C5a receptor 1 (C5aR1) and C5a receptor 2 (C5aR2, or C5L2). C5aR2 is a non-G-protein-signalling receptor whose biological role remains controversial. Some of this controversy arises owing to the lack of selective ligands for C5aR2. In this study, a library of 61 peptides based on the C-terminus of C5a was assayed for the ability to selectively modulate C5aR2 function. Two ligands (P32 and P59) were identified as functionally selective C5aR2 ligands, exhibiting selective recruitment of β-arrestin 2 via C5aR2, partial inhibition of C5a-induced ERK1/2 activation and lipopolysaccharide-stimulated interleukin-6 release from human monocyte-derived macrophages. Importantly, neither ligand could induce ERK1/2 activation or inhibit C5a-induced ERK1/2 activation via C5aR1 directly. Finally, P32 inhibited C5a-mediated neutrophil mobilisation in wild-type, but not C5aR2(-/-) mice. These functionally selective ligands for C5aR2 are novel tools that can selectively modulate C5a activity in vitro and in vivo, and thus will be valuable tools to interrogate C5aR2 function.
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30
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Gu H, Fisher AJ, Mickler EA, Duerson F, Cummings OW, Peters-Golden M, Twigg HL, Woodruff TM, Wilkes DS, Vittal R. Contribution of the anaphylatoxin receptors, C3aR and C5aR, to the pathogenesis of pulmonary fibrosis. FASEB J 2016; 30:2336-50. [PMID: 26956419 DOI: 10.1096/fj.201500044] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 02/22/2016] [Indexed: 12/24/2022]
Abstract
Complement activation, an integral arm of innate immunity, may be the critical link to the pathogenesis of idiopathic pulmonary fibrosis (IPF). Whereas we have previously reported elevated anaphylatoxins-complement component 3a (C3a) and complement component 5a (C5a)-in IPF, which interact with TGF-β and augment epithelial injury in vitro, their role in IPF pathogenesis remains unclear. The objective of the current study is to determine the mechanistic role of the binding of C3a/C5a to their respective receptors (C3aR and C5aR) in the progression of lung fibrosis. In normal primary human fetal lung fibroblasts, C3a and C5a induces mesenchymal activation, matrix synthesis, and the expression of their respective receptors. We investigated the role of C3aR and C5aR in lung fibrosis by using bleomycin-injured mice with fibrotic lungs, elevated local C3a and C5a, and overexpression of their receptors via pharmacologic and RNA interference interventions. Histopathologic examination revealed an arrest in disease progression and attenuated lung collagen deposition (Masson's trichrome, hydroxyproline, collagen type I α 1 chain, and collagen type I α 2 chain). Pharmacologic or RNA interference-specific interventions suppressed complement activation (C3a and C5a) and soluble terminal complement complex formation (C5b-9) locally and active TGF-β1 systemically. C3aR/C5aR antagonists suppressed local mRNA expressions of tgfb2, tgfbr1/2, ltbp1/2, serpine1, tsp1, bmp1/4, pdgfbb, igf1, but restored the proteoglycan, dcn Clinically, compared with pathologically normal human subjects, patients with IPF presented local induction of C5aR, local and systemic induction of soluble C5b-9, and amplified expression of C3aR/C5aR in lesions. The blockade of C3aR and C5aR arrested the progression of fibrosis by attenuating local complement activation and TGF-β/bone morphologic protein signaling as well as restoring decorin, which suggests a promising therapeutic strategy for patients with IPF.-Gu, H., Fisher, A. J., Mickler, E. A., Duerson, F., III, Cummings, O. W., Peters-Golden, M., Twigg, H. L., III, Woodruff, T. M., Wilkes, D. S., Vittal, R. Contribution of the anaphylatoxin receptors, C3aR and C5aR, to the pathogenesis of pulmonary fibrosis.
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Affiliation(s)
- Hongmei Gu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Amanda J Fisher
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Elizabeth A Mickler
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Frank Duerson
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Oscar W Cummings
- Department of Pathology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Marc Peters-Golden
- Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Homer L Twigg
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Trent M Woodruff
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - David S Wilkes
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ragini Vittal
- Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, Michigan, USA
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31
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Differential Contributions of the Complement Anaphylotoxin Receptors C5aR1 and C5aR2 to the Early Innate Immune Response against Staphylococcus aureus Infection. Pathogens 2015; 4:722-38. [PMID: 26512700 PMCID: PMC4693161 DOI: 10.3390/pathogens4040722] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 01/14/2023] Open
Abstract
The complement anaphylatoxin C5a contributes to host defense against Staphylococcus aureus. In this study, we investigated the functional role of the two known C5a receptors, C5aR1 and C5aR2, in the host response to S. aureus. We found that C5aR1−/− mice exhibited greater susceptibility to S. aureus bloodstream infection than wild type and C5aR2−/− mice, as demonstrated by the significantly higher bacterial loads in the kidneys and heart at 24 h of infection, and by the higher levels of inflammatory IL-6 in serum. Histological and immunohistochemistry investigation of infected kidneys at 24 h after bacterial inoculation revealed a discrete infiltration of neutrophils in wild type mice but already well-developed abscesses consisting of bacterial clusters surrounded by a large number of neutrophils in both C5aR1−/− and C5aR2−/− mice. Furthermore, blood neutrophils from C5aR1−/− mice were less efficient than those from wild type or C5aR2−/− mice at killing S. aureus. The requirement of C5aR1 for efficient killing of S. aureus was also demonstrated in human blood after disrupting C5a-C5aR1 signaling using specific inhibitors. These results demonstrated a role for C5aR1 in S. aureus clearance as well as a role for both C5aR1 and C5aR2 in the orchestration of the inflammatory response during infection.
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32
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Spaan AN, Schiepers A, de Haas CJC, van Hooijdonk DDJJ, Badiou C, Contamin H, Vandenesch F, Lina G, Gerard NP, Gerard C, van Kessel KPM, Henry T, van Strijp JAG. Differential Interaction of the Staphylococcal Toxins Panton-Valentine Leukocidin and γ-Hemolysin CB with Human C5a Receptors. THE JOURNAL OF IMMUNOLOGY 2015; 195:1034-43. [PMID: 26091719 DOI: 10.4049/jimmunol.1500604] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 05/22/2015] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus is well adapted to the human host. Evasion of the host phagocyte response is critical for successful infection. The staphylococcal bicomponent pore-forming toxins Panton-Valentine leukocidin LukSF-PV (PVL) and γ-hemolysin CB (HlgCB) target human phagocytes through interaction with the complement receptors C5aR1 and C5aR2. Currently, the apparent redundancy of both toxins cannot be adequately addressed in experimental models of infection because mice are resistant to PVL and HlgCB. The molecular basis for species specificity of the two toxins in animal models is not completely understood. We show that PVL and HlgCB feature distinct activity toward neutrophils of different mammalian species, where activity of PVL is found to be restricted to fewer species than that of HlgCB. Overexpression of various mammalian C5a receptors in HEK cells confirms that cytotoxicity toward neutrophils is driven by species-specific interactions of the toxins with C5aR1. By taking advantage of the species-specific engagement of the toxins with their receptors, we demonstrate that PVL and HlgCB differentially interact with human C5aR1 and C5aR2. In addition, binding studies illustrate that different parts of the receptor are involved in the initial binding of the toxin and the subsequent formation of lytic pores. These findings allow a better understanding of the molecular mechanism of pore formation. Finally, we show that the toxicity of PVL, but not of HlgCB, is neutralized by various C5aR1 antagonists. This study offers directions for the development of improved preclinical models for infection, as well as for the design of drugs antagonizing leukocidin toxicity.
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Affiliation(s)
- András N Spaan
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands; Centre International de Recherche en Infectiologie, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Inserm, Unité 1111, 69007 Lyon, France
| | - Ariën Schiepers
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Carla J C de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Davy D J J van Hooijdonk
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Cédric Badiou
- Centre International de Recherche en Infectiologie, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Inserm, Unité 1111, 69007 Lyon, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5308, 69007 Lyon, France
| | | | - François Vandenesch
- Centre International de Recherche en Infectiologie, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Inserm, Unité 1111, 69007 Lyon, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5308, 69007 Lyon, France; Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, 69007 Lyon, France
| | - Gérard Lina
- Centre International de Recherche en Infectiologie, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Inserm, Unité 1111, 69007 Lyon, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5308, 69007 Lyon, France; Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, 69007 Lyon, France
| | - Norma P Gerard
- Ina Sue Perlmutter Laboratory, Division of Pulmonary Medicine, Department of Pediatrics, Boston Children's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115; and Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Craig Gerard
- Ina Sue Perlmutter Laboratory, Division of Pulmonary Medicine, Department of Pediatrics, Boston Children's Hospital, Department of Medicine, Harvard Medical School, Boston, MA 02115; and
| | - Kok P M van Kessel
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands
| | - Thomas Henry
- Centre International de Recherche en Infectiologie, Université Lyon 1 and Ecole Normale Supérieure de Lyon, 69007 Lyon, France; Inserm, Unité 1111, 69007 Lyon, France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5308, 69007 Lyon, France
| | - Jos A G van Strijp
- Department of Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, the Netherlands;
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Selle J, Asare Y, Köhncke J, Alampour-Rajabi S, Shagdarsuren G, Klos A, Weber C, Jankowski J, Shagdarsuren E. Atheroprotective role of C5ar2 deficiency in apolipoprotein E-deficient mice. Thromb Haemost 2015; 114:848-58. [PMID: 26084965 DOI: 10.1160/th14-12-1075] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 05/20/2015] [Indexed: 12/22/2022]
Abstract
Atherogenic processes and vascular remodelling after arterial injury are controlled and driven by a plethora of factors amongst which the activation of the complement system is pivotal. Recently, we reported a clear correlation between high expressions of the second receptor for complement anaphylatoxin C5a, the C5a receptor-like 2 (C5L2, C5aR2), with high pro-inflammatory cytokine expression in advanced human atherosclerotic plaques. This prompted us to speculate that C5aR2 might have a functional role in atherosclerosis. We, therefore, investigated the role of C5aR2 in atherosclerosis and vascular remodelling. Here, we demonstrate that C5ar2 deletion, in atherosclerosis-prone mice, attenuates atherosclerotic as well as neointimal plaque formation, reduces macrophages and CD3+ T cells and induces features of plaque stability, as analysed by histomorphometry and quantitative immunohistochemistry. As a possible underlying mechanism, C5ar2-deficient plaques showed significantly reduced expression of C5a receptor (C5ar1), Tnf-α as well as Vcam-1, as determined by qPCR and quantitative immunohistochemistry. In addition, in vitro mechanistic studies revealed a reduction of these pro-inflammatory and pro-atherosclerotic mediators in C5ar2-deficient macrophages. Finally, blocking C5ar1 with antagonist JPE1375, in C5ar2(-/-)/Apoe(-/-) mice, led to a further reduction in neointimal plaque formation with reduced inflammation. In conclusion, C5ar2 deficiency attenuates atherosclerosis and neointimal plaque formation after arterial injury. This identifies C5aR2 as a promising target to reduce atherosclerosis and restenosis after vascular interventions.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Erdenechimeg Shagdarsuren
- Erdenechimeg Shagdarsuren, MD, Institute for Molecular Cardiovascular Research, Universitätsklinikum der RWTH Aachen, Pauwelsstraße 30, 52074 Aachen, Germany, Tel.: +49 241 8036584, Fax: +49 241 8082703, E-mail:
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34
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Darling VR, Hauke RJ, Tarantolo S, Agrawal DK. Immunological effects and therapeutic role of C5a in cancer. Expert Rev Clin Immunol 2014; 11:255-63. [PMID: 25387724 DOI: 10.1586/1744666x.2015.983081] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The specific role of C5a in cancer, especially in melanoma, has yet to be determined. Differential effects of C5a could be cancer specific. In the host defense system, C5a functions to protect the body from harmful entities via a plethora of mechanisms. Yet, C5a may also serve to potentiate cancerous process. C5a facilitates cellular proliferation and regeneration by attracting myeloid-derived suppressor cells and supporting tumor promotion. In this article, we critically reviewed the properties, mechanisms of action and functions of C5a, with particular emphasis on cancer inhibition and promotion, and clinical application of such knowledge in better management of patients with cancer. Outstanding questions and future directions in regard to the function of C5a in melanoma and other cancers are discussed.
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Affiliation(s)
- Victoria R Darling
- Center for Clinical and Translational Science, Creighton University School of Medicine, Omaha, NE, USA
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35
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Vijayan S, Asare Y, Grommes J, Soehnlein O, Lutgens E, Shagdarsuren G, Togtokh A, Jacobs MJ, Fischer JW, Bernhagen J, Weber C, Schober A, Shagdarsuren E. High expression of C5L2 correlates with high proinflammatory cytokine expression in advanced human atherosclerotic plaques. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2123-33. [PMID: 24819959 DOI: 10.1016/j.ajpath.2014.04.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 03/25/2014] [Accepted: 04/07/2014] [Indexed: 12/21/2022]
Abstract
The complement anaphylatoxin C5a functions through its two receptors, C5aR (CD88) and C5a receptor-like 2 (C5L2). Their role in atherosclerosis is incompletely understood. We, therefore, analyzed C5aR and probed the yet unknown expression and function of C5L2 in human atherogenesis. Human atherosclerotic plaques obtained by endarterectomy were staged and analyzed for C5L2 and C5aR by IHC and quantitative real-time PCR. C5L2-expressing cells in plaques were mostly macrophages, less neutrophils and endothelial cells, as determined by double immunostaining. Although early influx of C5aR(+) cells was detected, C5L2 levels increased with lesion complexity and colocalized with C5aR and oxidized low-density lipoprotein. Gene expression of C5L2 and C5aR showed similar trends, such as the receptor-expressing cells. The expression of C5L2 in advanced lesions correlated with increased levels of IL-1β and tumor necrosis factor-α in plaques. Furthermore, in vitro experiments in macrophages from wild-type and C5l2- and C5ar-deficient mice corroborated the contributing role of C5l2 in oxidized low-density lipoprotein-pretreated C5a-induced cytokine expression, as measured by enzyme-linked immunosorbent assay. Finally, C5l2- and C5ar-deficient peripheral blood mononuclear cells showed less arrest on tumor necrosis factor-α-stimulated mouse endothelial cells in vitro when compared with wild-type controls. Taken together, prominent C5L2 expression in advanced atherosclerotic stages directly correlates with high levels of proinflammatory cytokines. This might indicate a proinflammatory role of C5L2 in atherosclerosis that needs to be pursued in the future by applying in vivo mouse models.
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Affiliation(s)
- Santosh Vijayan
- Institute for Molecular Cardiovascular Research, University Hospital, Aachen, Germany; Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Yaw Asare
- Institute for Molecular Cardiovascular Research, University Hospital, Aachen, Germany; Institute of Biochemistry and Molecular Cell Biology, University Hospital, Aachen, Germany
| | - Jochen Grommes
- European Vascular Centre Aachen-Maastricht, University Hospital, Aachen, Germany
| | - Oliver Soehnlein
- Institute for Molecular Cardiovascular Research, University Hospital, Aachen, Germany; Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Esther Lutgens
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany; Department of Medical Biochemistry, Amsterdam Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Gansuvd Shagdarsuren
- Department of Nephrology, Health Sciences University of Mongolia, Ulaanbaatar, Mongolia
| | - Ariunaa Togtokh
- Department of Nephrology, Health Sciences University of Mongolia, Ulaanbaatar, Mongolia
| | - Michael J Jacobs
- European Vascular Centre Aachen-Maastricht, University Hospital, Aachen, Germany; European Vascular Center Aachen-Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Jens W Fischer
- Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Jürgen Bernhagen
- Institute of Biochemistry and Molecular Cell Biology, University Hospital, Aachen, Germany; August-Lenz-Stiftung at Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Christian Weber
- Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany; Department of Medical Biochemistry, Amsterdam Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Andreas Schober
- Institute for Molecular Cardiovascular Research, University Hospital, Aachen, Germany; Institute for Cardiovascular Prevention, Ludwig-Maximilians-University Munich, Munich, Germany
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Complement mediates a primed inflammatory response after traumatic lung injury. J Trauma Acute Care Surg 2014; 76:601-8; discussion 608-9. [PMID: 24553525 DOI: 10.1097/ta.0000000000000129] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Pulmonary contusion (PC) is a common, potentially lethal injury that results in the priming for exaggerated responses to subsequent immune challenge such as an infection (second hit). We hypothesize a PC-induced complement (C) activation participates in the priming effect for a second hit. METHODS Male, 8 weeks to 9 weeks, C57BL/6 mice (wild-type, C5) underwent blunt chest trauma resulting in PC. At 3 hours/24 hours after injury, the inflammatory response was measured in tissue, serum, and bronchoalveolar lavage (BAL). The thrombin inhibitor, hirudin, was used to determine if injury-induced thrombin participated in the activation of C. Injury-primed responses were tested by challenging injured mice with bacterial endotoxin (lipopolysaccharide, LPS) as a second hit. Inflammatory responses were assessed at 4 hours after LPS challenge. Data were analyzed using one-way analysis of variance with Bonferroni multiple comparison posttest (significance, p ≤ 0.05). Protocols were approved by the Institutional Animal Care and Use Committee. RESULTS We found significantly increased levels of C5a in the BAL of injured animals as early as 24 hours, persisting for up to 72 hours after injury. Hirudin-treated injured mice had significantly decreased levels of thrombin in the BAL that correlated with reduced C5a levels. Injured mice challenged with intratracheal (IT) LPS had increased C5a and inflammatory response. Conversely, inhibition of C5a or its receptor, C5aR, before LPS challenge correlated with decreased inflammatory responses; C5a-deficient mice showed a similar loss of primed response to LPS challenge. CONCLUSION Complement C5a levels in the BAL are increased over several days after PC. Premorbid inhibition of thrombin markedly decreases C5a levels after PC, suggesting that thrombin-induced C activation is the major pathway of activation after PC. Similarly, inhibition of C5a after PC will decrease injury-primed responses to LPS stimulation. Our findings suggest cross-talk between the coagulation and complement systems that induce immune priming after PC.
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C5a2 can modulate ERK1/2 signaling in macrophages via heteromer formation with C5a1 and β-arrestin recruitment. Immunol Cell Biol 2014; 92:631-9. [PMID: 24777312 DOI: 10.1038/icb.2014.32] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/02/2014] [Accepted: 04/02/2014] [Indexed: 01/08/2023]
Abstract
The complement system is a major component of our innate immune system, in which the complement proteins C5a and C5a-des Arg bind to two G-protein-coupled receptors: namely, the C5a receptor (C5a1) and C5a receptor like-2 receptor (C5a2, formerly called C5L2). Recently, it has been demonstrated that C5a, but not C5a-des Arg, upregulates heteromer formation between C5a1 and C5a2, leading to an increase in IL-10 release from human monocyte-derived macrophages (HMDMs). A bioluminescence resonance energy transfer (BRET) assay was used to assess the recruitment of β-arrestins by C5a and C5a-des Arg at the C5a1 and C5a2 receptors. C5a demonstrated elevated β-arrestin 2 recruitment levels in comparison with C5a-des Arg, whereas no significant difference was observed at C5a2. A constitutive complex that formed between β-arrestin 2 and C5a2 accounted for half of the BRET signal observed. Interestingly, both C5a and C5a-des Arg exhibited higher potency for β-arrestin 2 recruitment via C5a2, indicating preference for C5a2 over C5a1. When C5a was tested in a functional ERK1/2 assay in HMDMs, inhibition of ERK1/2 was observed only at concentrations at or above the EC50 for heteromer formation. This suggested that increased recruitment of the β-arrestin-C5a2 complex at these C5a concentrations might have an inhibitory role on C5a1 signaling through ERK1/2. An improved understanding of C5a2 modulation of signaling in acute inflammation could be of benefit in the development of ligands for conditions such as sepsis.
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Aman MJ, Adhikari RP. Staphylococcal bicomponent pore-forming toxins: targets for prophylaxis and immunotherapy. Toxins (Basel) 2014; 6:950-72. [PMID: 24599233 PMCID: PMC3968370 DOI: 10.3390/toxins6030950] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/22/2014] [Accepted: 02/26/2014] [Indexed: 01/09/2023] Open
Abstract
Staphylococccus aureus represents one of the most challenging human pathogens as well as a common colonizer of human skin and mucosal surfaces. S. aureus causes a wide range of diseases from skin and soft tissue infection (SSTI) to debilitating and life-threatening conditions such as osteomyelitis, endocarditis, and necrotizing pneumonia. The range of diseases reflects the remarkable diversity of the virulence factors produced by this pathogen, including surface antigens involved in the establishment of infection and a large number of toxins that mediate a vast array of cellular responses. The staphylococcal toxins are generally believed to have evolved to disarm the innate immune system, the first line of defense against this pathogen. This review focuses on recent advances on elucidating the biological functions of S. aureus bicomponent pore-forming toxins (BCPFTs) and their utility as targets for preventive and therapeutic intervention. These toxins are cytolytic to a variety of immune cells, primarily neutrophils, as well as cells with a critical barrier function. The lytic activity of BCPFTs towards immune cells implies a critical role in immune evasion, and a number of epidemiological studies and animal experiments relate these toxins to clinical disease, particularly SSTI and necrotizing pneumonia. Antibody-mediated neutralization of this lytic activity may provide a strategy for development of toxoid-based vaccines or immunotherapeutics for prevention or mitigation of clinical diseases. However, certain BCPFTs have been proposed to act as danger signals that may alert the immune system through an inflammatory response. The utility of a neutralizing vaccination strategy must be weighed against such immune-activating potential.
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Affiliation(s)
- M Javad Aman
- Integrated BioTherapeutics Inc., 21 Firstfield Rd., Gaithersburg, MD 20878, USA.
| | - Rajan P Adhikari
- Integrated BioTherapeutics Inc., 21 Firstfield Rd., Gaithersburg, MD 20878, USA.
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Poursharifi P, Lapointe M, Fisette A, Lu H, Roy C, Munkonda MN, Fairlie DP, Cianflone K. C5aR and C5L2 act in concert to balance immunometabolism in adipose tissue. Mol Cell Endocrinol 2014; 382:325-333. [PMID: 24397921 DOI: 10.1016/j.mce.2013.10.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 10/15/2013] [Indexed: 12/24/2022]
Abstract
Recent studies suggested that the immunometabolic receptors; C5aR and C5L2, constitutively self-associate into homo-/heterodimers and that acylation stimulating protein (ASP/C3adesArg) or C5a treatment of adipocytes increased their colocalization. The present study evaluates the C5aR contribution in adipocytes to the metabolic and immune responses elicited by ligand stimulation. The effects of C5a, ASP, and insulin on cytokine production, triglyceride synthesis (TGS), and key signaling pathways were evaluated in isolated primary adipocytes and cultured 3T3-L1 differentiated adipocytes. In addition, mRNA expression of IRS1 and PGC1α was compared in adipose tissue samples from WT vs. C5aRKO mice. Both C5a and ASP directly increased MCP-1 (238±4%; P<0.001, and 377±2% vs. basal 100%; P<0.001, respectively) and KC (413±11%; P<0.001, and 529±16%; P<0.001 vs. basal 100%, respectively) secretion, TGS (131±1%; P<0.001, and 152±6%; P<0.001, vs. basal 100% respectively), and Akt/NFκB phosphorylation pathways in adipocytes. However, in C5aRKO adipocytes, C5a effects were disrupted, while stimulatory effects of ASP were mostly maintained. Addition of C5a completely blocked ASP signaling and activity in both C5aRKO and WT adipocytes as well as 3T3-L1 adipocytes. Furthermore, C5aRKO adipocytes revealed impaired insulin stimulation of cytokine production, with partial impairment of signaling and TGS stimulation, consistent with decreased IRS1 and PGC1α mRNA expression in adipose tissue. These observations indicate the importance of C5aR in adipose tissue metabolism and immunity, which may be regulated through heterodimerization with C5L2.
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Affiliation(s)
- Pegah Poursharifi
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada; Department of Medicine, Laval University, Québec, QC, Canada
| | - Marc Lapointe
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada
| | - Alexandre Fisette
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada; Department of Medicine, Laval University, Québec, QC, Canada
| | - Huiling Lu
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada
| | - Christian Roy
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada; Department of Medicine, Laval University, Québec, QC, Canada
| | - Mercedes Nancy Munkonda
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada; Department of Medicine, Laval University, Québec, QC, Canada
| | - David P Fairlie
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Katherine Cianflone
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (CRIUCPQ), Québec, QC, Canada; Department of Medicine, Laval University, Québec, QC, Canada.
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Alexander SPH, Benson HE, Faccenda E, Pawson AJ, Sharman JL, Spedding M, Peters JA, Harmar AJ. The Concise Guide to PHARMACOLOGY 2013/14: G protein-coupled receptors. Br J Pharmacol 2013; 170:1459-581. [PMID: 24517644 PMCID: PMC3892287 DOI: 10.1111/bph.12445] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. G protein-coupled receptors are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.
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Affiliation(s)
- Stephen PH Alexander
- School of Life Sciences, University of Nottingham Medical SchoolNottingham, NG7 2UH, UK
| | - Helen E Benson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Elena Faccenda
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Adam J Pawson
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | - Joanna L Sharman
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
| | | | - John A Peters
- Neuroscience Division, Medical Education Institute, Ninewells Hospital and Medical School, University of DundeeDundee, DD1 9SY, UK
| | - Anthony J Harmar
- The University/BHF Centre for Cardiovascular Science, University of EdinburghEdinburgh, EH16 4TJ, UK
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Spaan AN, Henry T, van Rooijen WJM, Perret M, Badiou C, Aerts PC, Kemmink J, de Haas CJC, van Kessel KPM, Vandenesch F, Lina G, van Strijp JAG. The staphylococcal toxin Panton-Valentine Leukocidin targets human C5a receptors. Cell Host Microbe 2013; 13:584-594. [PMID: 23684309 DOI: 10.1016/j.chom.2013.04.006] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/15/2013] [Accepted: 04/09/2013] [Indexed: 12/14/2022]
Abstract
Panton-Valentine Leukocidin (PVL) is a staphylococcal bicomponent pore-forming toxin linked to severe invasive infections. Target-cell and species specificity of PVL are poorly understood, and the mechanism of action of this toxin in Staphylococcus aureus virulence is controversial. Here, we identify the human complement receptors C5aR and C5L2 as host targets of PVL, mediating both toxin binding and cytotoxicity. Expression and interspecies variations of the C5aR determine cell and species specificity of PVL. The C5aR binding PVL component, LukS-PV, is a potent inhibitor of C5a-induced immune cell activation. These findings provide insight into leukocidin function and staphylococcal virulence and offer directions for future investigations into individual susceptibility to severe staphylococcal disease.
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Affiliation(s)
- András N Spaan
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Thomas Henry
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France
| | | | - Magali Perret
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France
| | - Cédric Badiou
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France
| | - Piet C Aerts
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Johan Kemmink
- Medicinal Chemistry and Chemical Biology, Utrecht University, 3584CX Utrecht, The Netherlands
| | - Carla J C de Haas
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - Kok P M van Kessel
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands
| | - François Vandenesch
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France; Hospices Civils de Lyon, 69007 Lyon, France
| | - Gérard Lina
- CIRI, International Center for Infectiology Research, LabEx Ecofect, Université Lyon 1, 69007 Lyon, France; Inserm, U1111, 69007 Lyon, France; Ecole Normale Supérieure de Lyon, 69007 Lyon, France; CNRS, UMR5308, 69007 Lyon, France; Hospices Civils de Lyon, 69007 Lyon, France
| | - Jos A G van Strijp
- Medical Microbiology, University Medical Center Utrecht, 3584CX Utrecht, The Netherlands.
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Bachelerie F, Ben-Baruch A, Burkhardt AM, Combadiere C, Farber JM, Graham GJ, Horuk R, Sparre-Ulrich AH, Locati M, Luster AD, Mantovani A, Matsushima K, Murphy PM, Nibbs R, Nomiyama H, Power CA, Proudfoot AEI, Rosenkilde MM, Rot A, Sozzani S, Thelen M, Yoshie O, Zlotnik A. International Union of Basic and Clinical Pharmacology. [corrected]. LXXXIX. Update on the extended family of chemokine receptors and introducing a new nomenclature for atypical chemokine receptors. Pharmacol Rev 2013; 66:1-79. [PMID: 24218476 DOI: 10.1124/pr.113.007724] [Citation(s) in RCA: 636] [Impact Index Per Article: 57.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Sixteen years ago, the Nomenclature Committee of the International Union of Pharmacology approved a system for naming human seven-transmembrane (7TM) G protein-coupled chemokine receptors, the large family of leukocyte chemoattractant receptors that regulates immune system development and function, in large part by mediating leukocyte trafficking. This was announced in Pharmacological Reviews in a major overview of the first decade of research in this field [Murphy PM, Baggiolini M, Charo IF, Hébert CA, Horuk R, Matsushima K, Miller LH, Oppenheim JJ, and Power CA (2000) Pharmacol Rev 52:145-176]. Since then, several new receptors have been discovered, and major advances have been made for the others in many areas, including structural biology, signal transduction mechanisms, biology, and pharmacology. New and diverse roles have been identified in infection, immunity, inflammation, development, cancer, and other areas. The first two drugs acting at chemokine receptors have been approved by the U.S. Food and Drug Administration (FDA), maraviroc targeting CCR5 in human immunodeficiency virus (HIV)/AIDS, and plerixafor targeting CXCR4 for stem cell mobilization for transplantation in cancer, and other candidates are now undergoing pivotal clinical trials for diverse disease indications. In addition, a subfamily of atypical chemokine receptors has emerged that may signal through arrestins instead of G proteins to act as chemokine scavengers, and many microbial and invertebrate G protein-coupled chemokine receptors and soluble chemokine-binding proteins have been described. Here, we review this extended family of chemokine receptors and chemokine-binding proteins at the basic, translational, and clinical levels, including an update on drug development. We also introduce a new nomenclature for atypical chemokine receptors with the stem ACKR (atypical chemokine receptor) approved by the Nomenclature Committee of the International Union of Pharmacology and the Human Genome Nomenclature Committee.
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Affiliation(s)
- Francoise Bachelerie
- Chair, Subcommittee on Chemokine Receptors, Nomenclature Committee-International Union of Pharmacology, Bldg. 10, Room 11N113, NIH, Bethesda, MD 20892.
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Croker DE, Halai R, Fairlie DP, Cooper MA. C5a, but not C5a-des Arg, induces upregulation of heteromer formation between complement C5a receptors C5aR and C5L2. Immunol Cell Biol 2013; 91:625-33. [PMID: 24060963 DOI: 10.1038/icb.2013.48] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 11/09/2022]
Abstract
Receptors for C5a have an important role in innate immunity and inflammation where their expression and activation is tightly regulated. There are two known receptors for C5a: the C5a receptor (C5aR) and the C5a receptor like-2 (C5L2) receptor. Here we hypothesized that activation of C5aR might lead to heteromer formation with C5L2, as a downregulatory mechanism for C5aR signaling. To investigate this experimentally, bioluminescent resonance energy transfer (BRET) was implemented and supported by wide-field microscopy to analyze receptor localization in transfected HEK293 cells and human monocyte-derived macrophages (HMDM). BRET experiments indicated the presence of constitutive C5aR-C5L2 heteromers, where C5a, but not C5a-des Arg, was able to induce further heteromer formation, which was inhibited by a C5aR-specific antagonist. The data obtained suggest that C5aR-C5L2 can form heteromers in a process enhanced by C5a, but not by C5a-des Arg. There was also a significant difference in the levels of the anti-inflammatory cytokine IL-10 detected in HMDM following exposure to C5a compared with that seen for C5a-des Arg but no differences in the pro-inflammatory cytokines TNFα and IL-6. These subtle differences in C5a and C5a-des Arg induced receptor function may be of benefit in understanding the regulation of C5a in acute inflammation.
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Affiliation(s)
- Daniel E Croker
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
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Wang R, Lu B, Gerard C, Gerard NP. Disruption of the complement anaphylatoxin receptor C5L2 exacerbates inflammation in allergic contact dermatitis. THE JOURNAL OF IMMUNOLOGY 2013; 191:4001-9. [PMID: 24043888 DOI: 10.4049/jimmunol.1301626] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The complement anaphylatoxin C5a is a critical mediator of allergic contact dermatitis, bridging essential aspects of innate and adaptive immunity. This anaphylatoxin functions by interacting with two 7-transmembrane segment receptors, the C5aR and C5L2. The C5aR is a classical G protein coupled receptor, whereas C5L2 is deficient in coupling to G proteins because of variations in the sequence. Our previous work in human neutrophils revealed a unique role for C5L2 in negatively modulating anaphylatoxin receptor mediated cellular activation through interactions with β-arrestin. When C5L2 is deficient, C5aR-mediated β-arrestin signaling is greatly enhanced. The work described in this study was undertaken first to determine the effect of C5L2 deficiency in a murine model of contact sensitivity, and second to determine whether the resultant exacerbation of inflammatory parameters reflects a negative modulatory function of C5L2 on the C5aR. First, we find dramatic increases in inflammation in C5L2(-/-) animals compared with wild type mice. Second, these increases are completely reversed following administration of mAb against the C5aR. Thus, in allergic contact sensitivity, as in isolated human neutrophils, C5L2 functions to suppress C5a-C5aR-mediated responses, further underscoring its role as a negative regulator of anaphylatoxin activity.
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Affiliation(s)
- Ruobing Wang
- Ina Sue Perlmutter Laboratory, Division of Respiratory Diseases, Department of Pediatrics, Children's Hospital, Boston, MA 02115
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Obesity-inducing diet promotes acylation stimulating protein resistance. Biochem Biophys Res Commun 2013; 437:403-7. [PMID: 23831465 DOI: 10.1016/j.bbrc.2013.06.090] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 06/24/2013] [Indexed: 01/19/2023]
Abstract
Acylation stimulating protein (ASP) is an adipokine derived from the immune complement system that is involved in energy homeostasis and inflammation. ASP acts on and correlates positively with postprandial fat clearance in healthy subjects. However, in obesity, ASP levels are elevated and correlate inversely with fat clearance, indicative of a potential resistance to ASP. Using a mouse model, we hypothesized that, over time, diet-induced obesity (DIO) would result in development of ASP insensitivity, as compared to chow-fed animals as controls. Injection of recombinant ASP in DIO mice failed to accelerate fat clearance to the same extent as in chow-fed mice. DIO mice exhibited higher basal levels of plasma ASP and, after 30weeks of diet, showed lower ASP receptor (C5L2) expression in adipose tissue compared to chow-fed mice. Additionally, ex vivo ASP stimulation failed to induce normal Ser(473)AKT phosphorylation in adipose tissue from DIO mice VS chow-fed controls. These results demonstrate for the first time a state of diet-induced ASP resistance. Changes in the ASP-C5L2 pathway dynamics in obesity could alter the development of obesity and co-morbidities such as atherosclerosis and type 2 diabetes.
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Hao J, Wang C, Yuan J, Chen M, Zhao MH. A pro-inflammatory role of C5L2 in C5a-primed neutrophils for ANCA-induced activation. PLoS One 2013; 8:e66305. [PMID: 23785491 PMCID: PMC3681967 DOI: 10.1371/journal.pone.0066305] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/03/2013] [Indexed: 12/21/2022] Open
Abstract
Background The complement system is crucial for the development of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). In particular, C5a and its receptor on neutrophils, CD88, play a central role. The functional role of the second receptor of C5a, C5L2, remains unclear. In the current study, we investigated the role of C5L2 in C5a-primed neutrophils for ANCA-induced activation. Methods The effect of blocking C5L2 by anti-human C5L2 blocking antibody were tested on respiratory burst and degranulation of C5a-primed neutrophils activated with ANCA, as well as on membrane-bound proteinase 3 (mPR3) and concentration of myeloperoxidase (MPO) in supernatant of C5a-primed neutrophils. An antagonist for CD88 was also employed. Results Blocking C5L2 resulted in a significantly decreased MPO concentration in the supernatant of C5a-primed neutrophils. mPR3 expression increased from 209.0±43.0 in untreated cells to 444.3±60.8 after C5a treatment (P<0.001), and decreased to 375.8±65.44, 342.2±54.3 and 313.7±43.6 by pre-incubating blocking C5L2 antibody at 2.5 µg/ml, 5 µg/ml or 10 µg/ml (compared with C5a-priming group, P<0.001, P<0.001, and P<0.001), respectively. In C5a-primed neutrophils, subsequently activating with MPO-ANCA-positive IgG, the MFI value was 425.8±160.6, which decreased to 292.8±141.2, 289.7±130.0 and 280.3±136.4 upon pre-incubation with mouse anti-human C5L2 blocking antibody at 2.5 µg/ml, 5 µg/ml or 10 µg/ml (compared with C5a-primed neutrophils, for MPO-ANCA-positive IgG-induced activation, P<0.05, P<0.05, and P<0.05), respectively. Blocking C5L2 also resulted in significantly decreased C5a-primed neutrophils for PR3-ANCA-positive IgG-induced activation. Moreover, the lactoferrin concentration in the supernant significantly decreased in pre-incubation with anti-human C5L2 blocking antibody, compared with C5a-primed neutrophils induced by PR3- or MPO-ANCA-positive IgG. Conclusions C5L2 may be implicated in the pro-inflammatory role in C5a-primed neutrophils for ANCA-induced activation.
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MESH Headings
- Antibodies, Antineutrophil Cytoplasmic/immunology
- Antibodies, Antineutrophil Cytoplasmic/metabolism
- Antibodies, Blocking/pharmacology
- Antibodies, Monoclonal/pharmacology
- Cell Degranulation/drug effects
- Cell Degranulation/immunology
- Cell Membrane/metabolism
- Complement C5a/immunology
- Culture Media, Conditioned/metabolism
- Humans
- Neutrophil Activation/drug effects
- Neutrophil Activation/immunology
- Neutrophils/drug effects
- Neutrophils/immunology
- Neutrophils/metabolism
- Peptide Hydrolases/metabolism
- Peroxidase/metabolism
- Protein Transport
- Receptor, Anaphylatoxin C5a/antagonists & inhibitors
- Receptor, Anaphylatoxin C5a/metabolism
- Receptors, Chemokine/antagonists & inhibitors
- Receptors, Chemokine/immunology
- Receptors, Chemokine/metabolism
- Respiratory Burst/drug effects
- Respiratory Burst/immunology
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Affiliation(s)
- Jian Hao
- Renal Division, Department of Medicine, Peking University, First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Peking-Tsinghua Center for Life Sciences, Beijing, China
- Renal Division, Department of Medicine, The Affiliated Hospital of Inner Mongolia Medical College Huhehot, Inner Mongolia, China
| | - Chen Wang
- Renal Division, Department of Medicine, Peking University, First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Jun Yuan
- Renal Division, Department of Medicine, Peking University, First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Min Chen
- Renal Division, Department of Medicine, Peking University, First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Peking-Tsinghua Center for Life Sciences, Beijing, China
- * E-mail:
| | - Ming-Hui Zhao
- Renal Division, Department of Medicine, Peking University, First Hospital, Peking University Institute of Nephrology, Key Laboratory of Renal Disease, Ministry of Health of China, Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Peking-Tsinghua Center for Life Sciences, Beijing, China
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Klos A, Wende E, Wareham KJ, Monk PN. International Union of Basic and Clinical Pharmacology. [corrected]. LXXXVII. Complement peptide C5a, C4a, and C3a receptors. Pharmacol Rev 2013; 65:500-43. [PMID: 23383423 DOI: 10.1124/pr.111.005223] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The activation of the complement cascade, a cornerstone of the innate immune response, produces a number of small (74-77 amino acid) fragments, originally termed anaphylatoxins, that are potent chemoattractants and secretagogues that act on a wide variety of cell types. These fragments, C5a, C4a, and C3a, participate at all levels of the immune response and are also involved in other processes such as neural development and organ regeneration. Their primary function, however, is in inflammation, so they are important targets for the development of antiinflammatory therapies. Only three receptors for complement peptides have been found, but there are no satisfactory antagonists as yet, despite intensive investigation. In humans, there is a single receptor for C3a (C3a receptor), no known receptor for C4a, and two receptors for C5a (C5a₁ receptor and C5a₂ receptor). The most recently characterized receptor, the C5a₂ receptor (previously known as C5L2 or GPR77), has been regarded as a passive binding protein, but signaling activities are now ascribed to it, so we propose that it be formally identified as a receptor and be given a name to reflect this. Here, we describe the complex biology of the complement peptides, introduce a new suggested nomenclature, and review our current knowledge of receptor pharmacology.
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Affiliation(s)
- Andreas Klos
- Department for Medical Microbiology, Medical School Hannover, Hannover, Germany
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Abstract
C3a and C5a (also called anaphylatoxins) are inflammatory peptides generated during complement activation. They do not only play important roles in innate immunity through the initiation and regulation of inflammatory responses, but also significantly influence adaptive immune responses. Organ transplantation triggers an initial inflammatory response and subsequent to the specific immune response (also called the alloimmune response), both of which contribute to graft rejection. Emerging evidence suggests that anaphylatoxins, particularly C5a, are significantly involved in both inflammatory and alloimmune responses following organ transplantation, thus influencing graft outcome. This review will provide the information on our current understanding of the roles for anaphylatoxins in ischemia-reperfusion injury, graft rejection, and transplant tolerance, and the therapeutic potential of targeting anaphylatoxin receptors in organ transplantation.
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Tillmann S, Bernhagen J, Noels H. Arrest Functions of the MIF Ligand/Receptor Axes in Atherogenesis. Front Immunol 2013; 4:115. [PMID: 23720662 PMCID: PMC3655399 DOI: 10.3389/fimmu.2013.00115] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 04/29/2013] [Indexed: 12/17/2022] Open
Abstract
Macrophage migration inhibitory factor (MIF) has been defined as an important chemokine-like function (CLF) chemokine with an essential role in monocyte recruitment and arrest. Adhesion of monocytes to the vessel wall and their transendothelial migration are critical in atherogenesis and many other inflammatory diseases. Chemokines carefully control all steps of the monocyte recruitment process. Those chemokines specialized in controlling arrest are typically immobilized on the endothelial surface, mediating the arrest of rolling monocytes by chemokine receptor-triggered pathways. The chemokine receptor CXCR2 functions as an important arrest receptor on monocytes. An arrest function has been revealed for the bona fide CXCR2 ligands CXCL1 and CXCL8, but genetic studies also suggested that additional arrest chemokines are likely to be involved in atherogenic leukocyte recruitment. While CXCR2 is known to interact with numerous CXC chemokine ligands, the CLF chemokine MIF, which structurally does not belong to the CXC chemokine sub-family, was surprisingly identified as a non-cognate ligand of CXCR2, responsible for critical arrest functions during the atherogenic process. MIF was originally identified as macrophage migration inhibitory factor (this function being eponymous), but is now known as a potent inflammatory cytokine with CLFs including chemotaxis and leukocyte arrest. This review will cover the mechanisms underlying these functions, including MIF’s effects on LFA1 integrin activity and signal transduction, and will discuss the structural similarities between MIF and the bona fide CXCR2 ligand CXCL8 while emphasizing the structural differences. As MIF also interacts with CXCR4, a chemokine receptor implicated in CXCL12-elicited lymphocyte arrest, the arrest potential of the MIF/CXCR4 axis will also be scrutinized as well as the recently identified role of pericyte MIF in attracting leukocytes exiting through venules as part of the pericyte “motility instruction program.”
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Affiliation(s)
- Sabine Tillmann
- Institute of Biochemistry and Molecular Cell Biology, RWTH Aachen University Aachen, Germany
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Roy C, Gupta A, Fisette A, Lapointe M, Poursharifi P, Richard D, Lu H, Lu B, Gerard N, Gerard C, Cianflone K. C5a receptor deficiency alters energy utilization and fat storage. PLoS One 2013; 8:e62531. [PMID: 23667486 PMCID: PMC3646841 DOI: 10.1371/journal.pone.0062531] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 03/22/2013] [Indexed: 01/26/2023] Open
Abstract
OBJECTIVE To investigate the impact of whole body C5a receptor (C5aR) deficiency on energy metabolism and fat storage. DESIGN Male wildtype (WT) and C5aR knockout (C5aRKO) mice were fed a low fat (CHOW) or a high fat high sucrose diet-induced obesity (DIO) diet for 14 weeks. Body weight and food intake were measured weekly. Indirect calorimetry, dietary fatload clearance, insulin and glucose tolerance tests were also evaluated. Liver, muscle and adipose tissue mRNA gene expression were measured by RT-PCR. RESULTS At week one and 12, C5aRKO mice on DIO had increased oxygen consumption. After 12 weeks, although food intake was comparable, C5aRKO mice had lower body weight (-7% CHOW, -12% DIO) as well as smaller gonadal (-38% CHOW, -36% DIO) and inguinal (-29% CHOW, -30% DIO) fat pads than their WT counterparts. Conversely, in WT mice, C5aR was upregulated in DIO vs CHOW diets in gonadal adipose tissue, muscle and liver, while C5L2 mRNA expression was lower in C5aRKO on both diet. Furthermore, blood analysis showed lower plasma triglyceride and non-esterified fatty acid levels in both C5aRKO groups, with faster postprandial triglyceride clearance after a fatload. Additionally, C5aRKO mice showed lower CD36 expression in gonadal and muscle on both diets, while DGAT1 expression was higher in gonadal (CHOW) and liver (CHOW and DIO) and PPARγ was increased in muscle and liver. CONCLUSION These observations point towards a role (either direct or indirect) for C5aR in energy expenditure and fat storage, suggesting a dual role for C5aR in metabolism as well as in immunity.
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Affiliation(s)
- Christian Roy
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Abhishek Gupta
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Alexandre Fisette
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Marc Lapointe
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Pegah Poursharifi
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Denis Richard
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - HuiLing Lu
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
| | - Bao Lu
- Ina Sue Perlmutter Lab, Children’s Hospital, Harvard Medical School, Boston, Massachusetts United States of America
| | - Norma Gerard
- Ina Sue Perlmutter Lab, Children’s Hospital, Harvard Medical School, Boston, Massachusetts United States of America
| | - Craig Gerard
- Ina Sue Perlmutter Lab, Children’s Hospital, Harvard Medical School, Boston, Massachusetts United States of America
| | - Katherine Cianflone
- Centre de Recherche Institut Universitaire de Cardiologie & Pneumologie de Québec, Université Laval, Québec, Québec, Canada
- * E-mail:
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