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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Samuels JM, Coleman JR, Moore EE, Bartley M, Vigneshwar N, Cohen M, Silliman CC, Sauaia A, Banerjee A. Alternative Complement Pathway Activation Provokes a Hypercoagulable State with Diminished Fibrinolysis. Shock 2020; 53:560-5. [PMID: 31441792 DOI: 10.1097/SHK.0000000000001437] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Several disease processes trigger prolonged activation of the alternative complement pathway. Crosslinks between complement activation and physiologic changes in platelets and neutrophils have been identified, but how this interplay alters the hemostatic potential in humans remains undefined. We hypothesize that activation of the alternative pathway triggers a hypercoagulable state. METHODS C3/C5 convertase Cobra Venom Factor (CVF, 10 Units/mL) was employed to activate the alternative complement pathway in whole blood. Complement inhibition was completed with inhibitors for C3/C3b (Compstatin, 25 and 50 μM), C3a receptor (SB290157, 300 nM, C3aR), and C5a receptor (W54011, 6 nM, C5aR). Coagulation was assessed using native thrombelastography which produces the following: reaction time (R time); angle; maximum amplitude (MA); percent fibrinolysis at 30-min post-MA (LY30). RESULTS Inhibition with C3aR and C5aR inhibitors did not alter clot formation (R time, 11.2 vs 11.6 min, P = 0.36), clot strength (MA, 52.0 vs 52.3 mm, P = 0.43), or fibrinolysis (LY30, 1.6 vs 4.0%, P = 0.19). Compstatin did not influence clot formation or clot strength but did induce a dose-dependent increase in fibrinolysis (control LY30 3.0 vs 7.8% and 12.4% for 25 and 50 μM respectively, P = 0.0002). CVF increased MA (58.0 vs 62.8 mm, P < 0.0001), decreased LY30 (2.3 vs 1.4%, P = 0.004), and increased R time (8.4 vs 9.9 min, P = 0.008). Compstatin reversed the effects of CVF, while C5a reversed only the change in LY30. CONCLUSIONS C3 contributes to fibrinolysis, as inhibition with Compstatin enhanced fibrinolysis, and CVF cleavage of C3 decreased fibrinolysis. CVF also induced a hypercoagulable state with increased clot strength.
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Li X, Hao Z, Liu X, Li W. Deficiency of Mouse FHR-1 Homolog, FHR-E, Accelerates Sepsis, and Acute Kidney Injury Through Enhancing the LPS-Induced Alternative Complement Pathway. Front Immunol 2020; 11:1123. [PMID: 32636836 PMCID: PMC7316958 DOI: 10.3389/fimmu.2020.01123] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/07/2020] [Indexed: 11/26/2022] Open
Abstract
Alternative complement pathway (AP) plays an important role in the development of sepsis, which is life threatening. Deficiency of factor H-related protein 1 (FHR-1), which is a regulator of AP, has been considered as a susceptible factor for atypical hemolytic uremic syndrome (aHUS) and other types of nephropathy when an inducer such as infection exists. However, the underlying mechanism of the disease development is largely unknown. There is no report on CFHR1 gene knockout in any animal infection model and its function in vivo is still unclear. Here, a Cfhr1 knockout mouse was generated for investigating AP in sepsis and sepsis-induced acute kidney injury (AKI). We found that murine FHR-1 homolog (FHR-E) deficiency enhanced lipopolysaccharide (LPS)-induced AP activation both in vitro and in vivo and that Cfhr1 knockout mice exhibited more severe sepsis and AKI in response to LPS challenge. These results indicated that FHR-E deficiency promoted LPS-induced sepsis and AKI through AP over-activation, providing a mouse model for studying AP regulation and sepsis. This study revealed the function of FHR-E in vivo, which may further provide hints to the pathogenesis of FHR-1 deficiency-related diseases by enhancing LPS-induced AP activation.
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Affiliation(s)
- Xiangru Li
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Beijing, China.,Genetics and Birth Defects Control Center, National Center for Children's Health, Beijing, China
| | - Zhenhua Hao
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Beijing, China.,Genetics and Birth Defects Control Center, National Center for Children's Health, Beijing, China
| | - Xiaorong Liu
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Wei Li
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Beijing, China.,Genetics and Birth Defects Control Center, National Center for Children's Health, Beijing, China
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Brash JL, Horbett TA, Latour RA, Tengvall P. The blood compatibility challenge. Part 2: Protein adsorption phenomena governing blood reactivity. Acta Biomater 2019; 94:11-24. [PMID: 31226477 PMCID: PMC6642842 DOI: 10.1016/j.actbio.2019.06.022] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 06/13/2019] [Indexed: 12/13/2022]
Abstract
The adsorption of proteins is the initiating event in the processes occurring when blood contacts a "foreign" surface in a medical device, leading inevitably to thrombus formation. Knowledge of protein adsorption in this context has accumulated over many years but remains fragmentary and incomplete. Moreover, the significance and relevance of the information for blood compatibility are not entirely agreed upon in the biomaterials research community. In this review, protein adsorption from blood is discussed under the headings "agreed upon" and "not agreed upon or not known" with respect to: protein layer composition, effects on coagulation and complement activation, effects on platelet adhesion and activation, protein conformational change and denaturation, prevention of nonspecific protein adsorption, and controlling/tailoring the protein layer composition. STATEMENT OF SIGNIFICANCE: This paper is part 2 of a series of 4 reviews discussing the problem of biomaterial associated thrombogenicity. The objective was to highlight features of broad agreement and provide commentary on those aspects of the problem that were subject to dispute. We hope that future investigators will update these reviews as new scholarship resolves the uncertainties of today.
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Gonzalo-Gil E, García-Herrero C, Toldos O, Usategui A, Criado G, Pérez-Yagüe S, Barber DF, Pablos JL, Galindo M. Microthrombotic Renal Vascular Lesions Are Associated to Increased Renal Inflammatory Infiltration in Murine Lupus Nephritis. Front Immunol 2018; 9:1948. [PMID: 30210500 PMCID: PMC6120987 DOI: 10.3389/fimmu.2018.01948] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/07/2018] [Indexed: 12/30/2022] Open
Abstract
Background: Vascular microthrombotic lesions in lupus nephritis with or without antiphospholipid antibodies may relate to worse renal outcomes. Whether microthrombotic lesions are a consequence of renal inflammation or independently contribute to renal damage is unclear. Our aim was to investigate the relationship between microthrombotic renal vascular lesions and nephritis progression in MRL/lpr mice. Methods: MRL/lpr mice were analyzed for the presence of renal microvascular, glomerular and tubulointerstitial lesions and the effect of anti-aggregation (aspirin or clopidogrel) and dexamethasone on renal clinical and pathological manifestations was evaluated. Intravascular platelet aggregates (CD41), peri- (F4/80), and intraglomerular (Mac-2) macrophage infiltration, and C3 deposition were quantified by immunohistochemistry. Renal function was assessed by measuring proteinuria, and serum levels of creatinine and albumin. Anti-dsDNA and anti-cardiolipin antibodies, and thromboxane B2 levels were quantified by ELISA. Results: Frequency of microthrombotic renal lesions in MRL/lpr mice was high and was associated with immune-mediated renal damage. Proteinuria positively correlated with glomerular macrophage infiltration and was higher in mice with proliferative glomerular lesions. All mice had detectable anti-dsDNA and anti-cardiolipin IgG, regardless the presence of microthrombosis. Proteinuria and glomerular macrophage infiltration were significantly reduced in all treatment groups. Dexamethasone and platelet anti-aggregation similarly reduced glomerular damage and inflammation, but only platelet anti-aggregation significantly reduced anti-cardiolipin antibodies, renal complement deposition and thromboxane B2 levels. Conclusions: Platelet anti-aggregation reduced renal inflammatory damage, renal complement deposition, anti-cardiolipin antibodies, and thromboxane B2 levels and in MRL/lpr mice, suggesting that platelet activation has a pathogenic effect on immune-mediated nephritis. Our results point to MRL/lpr mice with lupus nephritis as an appropriate model to analyze the potential impact of anti-thrombotic intervention on renal inflammation.
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Affiliation(s)
| | | | - Oscar Toldos
- Servicio de Anatomía Patológica, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Alicia Usategui
- Instituto de Investigación, Hospital 12 de Octubre, Madrid, Spain
| | - Gabriel Criado
- Instituto de Investigación, Hospital 12 de Octubre, Madrid, Spain
| | | | | | - Jose L Pablos
- Servicio de Reumatología, Hospital Universitario 12 de Octubre, Madrid, Spain.,Universidad Complutense de Madrid, Madrid, Spain
| | - Maria Galindo
- Servicio de Reumatología, Hospital Universitario 12 de Octubre, Madrid, Spain.,Universidad Complutense de Madrid, Madrid, Spain
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Corban MT, Duarte-Garcia A, McBane RD, Matteson EL, Lerman LO, Lerman A. Antiphospholipid Syndrome: Role of Vascular Endothelial Cells and Implications for Risk Stratification and Targeted Therapeutics. J Am Coll Cardiol. 2017;69:2317-2330. [PMID: 28473138 DOI: 10.1016/j.jacc.2017.02.058] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 02/21/2017] [Accepted: 02/28/2017] [Indexed: 12/28/2022]
Abstract
Antiphospholipid syndrome (APS) is an autoimmune disease characterized by venous thromboembolism, arterial thrombosis, and obstetric morbidities in the setting of persistently positive levels of antiphospholipid antibodies measured on 2 different occasions 12 weeks apart. Patients with APS are at increased risk for accelerated atherosclerosis, myocardial infarction, stroke, and valvular heart disease. Vascular endothelial cell dysfunction mediated by antiphospholipid antibodies and subsequent complement system activation play a cardinal role in APS pathogenesis. Improved understanding of their pathogenic function could help in the risk stratification of patients with APS and provide new molecular therapeutic targets.
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Mizuno M, Suzuki Y, Ito Y. Complement regulation and kidney diseases: recent knowledge of the double-edged roles of complement activation in nephrology. Clin Exp Nephrol 2017; 22:3-14. [DOI: 10.1007/s10157-017-1405-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 03/14/2017] [Indexed: 12/28/2022]
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Mizuno T, Mizuno M, Imai M, Suzuki Y, Kushida M, Noda Y, Maruyama S, Okada H, Okada N, Matsuo S, Ito Y. Anti-C5a complementary peptide ameliorates acute peritoneal injury induced by neutralization of Crry and CD59. Am J Physiol Renal Physiol 2013; 305:F1603-16. [DOI: 10.1152/ajprenal.00681.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In peritoneal dialysis (PD) therapy, physical stresses such as exposure to peritoneal dialysate, catheter trauma, and peritonitis may induce peritoneal injury that can prevent continued long-term PD therapy. Therefore, protection of the peritoneum is an important target to enable long-term PD therapy in patients with end-stage renal disease. We previously showed that neutralization of the membrane complement regulators (CRegs) Crry and CD59 in rat peritoneum provokes development of acute peritoneal injury due to uncontrolled complement activation. C5a is a key effecter molecule of the complement system released during acute inflammation. Control of C5a has been proposed as a strategy to suppress inflammatory reactions and, because peritoneal injury is accompanied by inflammation, we hypothesized that C5a targeted therapy might be an effective way to suppress peritoneal injury. In the present study we used an established acute peritonitis model induced by neutralization of CRegs to investigate the effects on acute peritoneal injury of inhibiting C5a. Intravenous administration of an anti-C5a complementary peptide (AcPepA) up to 4 h after induction of injury significantly and dose-dependently prevented accumulation of inflammatory cells and reduced tissue damage in the model, accompanied by decreased C3b deposition. We show that C5a contributed to the development of peritoneal injury. Our results suggest that C5a is a target for preventing or treating peritoneal injury in patients undergoing prolonged PD therapy or with infectious complications.
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Affiliation(s)
- Tomohiro Mizuno
- Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Clinical Sciences and Neuropsychopharmacology, Meijo University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Masashi Mizuno
- Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Renal Replacement Therapy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masaki Imai
- Immunology, Nagoya City University Graduate School of Medicine, Nagoya, Japan; and
| | - Yasuhiro Suzuki
- Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Renal Replacement Therapy, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Mayu Kushida
- Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Clinical Sciences and Neuropsychopharmacology, Meijo University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Yukihiro Noda
- Clinical Sciences and Neuropsychopharmacology, Meijo University Graduate School of Pharmaceutical Sciences, Nagoya, Japan
| | - Shoichi Maruyama
- Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hidechika Okada
- Immunology, Nagoya City University Graduate School of Medicine, Nagoya, Japan; and
- Choju Medical Institute, Fukushimura Hospital, Toyohashi, Japan
| | - Noriko Okada
- Immunology, Nagoya City University Graduate School of Medicine, Nagoya, Japan; and
| | - Seiichi Matsuo
- Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuhiko Ito
- Nephrology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Renal Replacement Therapy, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Alexander JJ, Chaves L, Chang A, Quigg RJ. The C5a receptor has a key role in immune complex glomerulonephritis in complement factor H-deficient mice. Kidney Int 2012; 82:961-8. [PMID: 22832515 DOI: 10.1038/ki.2012.249] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Chronic serum sickness leads to the formation of glomerular immune complexes; however, C57BL/6 mice do not develop glomerulonephritis unless complement factor H (CFH) is absent from the plasma. Here we studied the role for C5a receptor (R) in this setting. The exaggerated humoral immune response in CFH−/− mice was normalized in CFH−/−C5aR−/− double knockout mice, highlighting the C5aR dependence. The CFH knockout mice developed proliferative glomerulonephritis with endocapillary F4/80+ macrophage infiltration, a process reduced in the double knockout mice. There was no interstitial inflammation by histologic criteria or flow cytometry for F4/80+Ly6ChiCCR2hi inflammatory macrophages. There were, however, more interstitial CD3+CD4+ T lymphocytes in CFH knockout mice with chronic serum sickness, while double knockout mice had greater than 5-fold more Ly6CloCCR2lo anti-inflammatory macrophages compared to the CFH knockout mice. Mice lacking C5aR were significantly protected from functional renal disease as assessed by blood urea nitrogen levels. Thus, IgG- and iC3b-containing immune complexes are not inflammatory in C57BL/6 mice. Yet when these mice lack CFH, sufficient C3b persists in glomeruli to generate C5a and activate C5aR.
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Cook WJ, Galakatos N, Boyar WC, Walter RL, Ealick SE. Structure of human desArg-C5a. Acta Crystallogr D Biol Crystallogr 2010; 66:190-7. [PMID: 20124699 DOI: 10.1107/s0907444909049051] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 11/17/2009] [Indexed: 11/10/2022]
Abstract
The anaphylatoxin C5a is derived from the complement component C5 during activation of the complement cascade. It is an important component in the pathogenesis of a number of inflammatory diseases. NMR structures of human and porcine C5a have been reported; these revealed a four-helix bundle stabilized by three disulfide bonds. The crystal structure of human desArg-C5a has now been determined in two crystal forms. Surprisingly, the protein crystallizes as a dimer and each monomer in the dimer has a three-helix core instead of the four-helix bundle noted in the NMR structure determinations. Furthermore, the N-terminal helices of the two monomers occupy different positions relative to the three-helix core and are completely different from the NMR structures. The physiological significance of these structural differences is unknown.
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Affiliation(s)
- William J Cook
- University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Abstract
As a key part of the innate immune system, complement plays an important role not only in defending against invading pathogens but also in many other biological processes. Inappropriate or excessive activation of complement has been linked to many autoimmune, inflammatory, and neurodegenerative diseases, as well as ischemia-reperfusion injury and cancer. A wide array of low molecular weight complement inhibitors has been developed to target various components of the complement cascade. Their efficacy has been demonstrated in numerous in vitro and in vivo experiments. Though none of these inhibitors has reached the market so far, some of them have entered clinical trials and displayed promising results. This review provides a brief overview of the currently developed low molecular weight complement inhibitors, including short peptides and synthetic small molecules, with an emphasis on those targeting components C1 and C3, and the anaphylatoxin receptors.
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Affiliation(s)
- Hongchang Qu
- Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, 401 Stellar Chance, 422 Curie Blvd., Philadelphia, PA 19104, USA
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Hirahashi J, Hishikawa K, Kaname S, Tsuboi N, Wang Y, Simon DI, Stavrakis G, Shimosawa T, Xiao L, Nagahama Y, Suzuki K, Fujita T, Mayadas TN. Mac-1 (CD11b/CD18) links inflammation and thrombosis after glomerular injury. Circulation 2009; 120:1255-65. [PMID: 19752320 PMCID: PMC2780001 DOI: 10.1161/circulationaha.109.873695] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Inflammation and thrombosis coexist in several disorders. Although it is recognized that leukocytes may induce a procoagulant state at sites of inflammation, the critical molecular determinants of this process remain largely unknown. METHODS AND RESULTS To examine mechanisms of inflammation-induced thrombosis, we developed a murine model of thrombotic glomerulonephritis (TGN), a known cause of acute renal failure in patients. This model, induced by lipopolysaccharide and antibody to the glomerular basement membrane, led to rapid glomerular neutrophil recruitment, thrombotic glomerular lesions with endothelial cell injury, and renal dysfunction. In mice immunodepleted of neutrophils or lacking the leukocyte-specific integrin Mac-1, neutrophil recruitment, endothelial injury, glomerular thrombosis, and acute renal failure were markedly attenuated despite the robust generation of renal cytokines. Neutrophil elastase is a likely effector of Mac-1 because its activity was reduced in Mac-1-deficient mice and the phenotype in mice deficient in Mac-1 or neutrophil elastase was similar. Platelets accumulated in glomerular capillaries within 4 hours of TGN before evidence of thrombosis. Platelet immunodepletion before TGN markedly exacerbated hematuria (hemorrhage), inflammation, and injury, whereas thrombocytopenic Mac-1-deficient mice remained resistant to disease, indicating that initial glomerular platelet deposition protects the vessel wall from neutrophil-mediated sequelae. The subsequent thrombosis relied on the interaction of Mac-1 on recruited neutrophils with glycoprotein Ibalpha on platelets as antibody-mediated disruption of this interaction attenuated TGN without affecting renal neutrophil accumulation. CONCLUSIONS These observations establish Mac-1 on neutrophils as a critical molecular link between inflammation and thrombosis and suggest it as an attractive target for antithrombotic therapy.
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Affiliation(s)
- Junichi Hirahashi
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
- Dept. of Pathology, Brigham and Women's Hospital & Harvard Medical School, Boston, Massachusetts
| | - Keiichi Hishikawa
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
| | - Shinya Kaname
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
| | - Naotake Tsuboi
- Dept. of Pathology, Brigham and Women's Hospital & Harvard Medical School, Boston, Massachusetts
| | - Yunmei Wang
- Department of Medicine, Case Cardiovascular Center, Case Western Reserve University School of Medicine, Cleveland, OH
| | - Daniel I. Simon
- Department of Medicine, Case Cardiovascular Center, Case Western Reserve University School of Medicine, Cleveland, OH
| | - George Stavrakis
- Dept. of Pathology, Brigham and Women's Hospital & Harvard Medical School, Boston, Massachusetts
| | - Tatsuo Shimosawa
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
| | - Ling Xiao
- Dept. of Pathology, Brigham and Women's Hospital & Harvard Medical School, Boston, Massachusetts
| | - Yutaka Nagahama
- IVD Department, R&D and Business Development Segment, Mitsubishi Chemical Medience Corporation, Tokyo, Japan
| | - Kazuo Suzuki
- Inflammation Program, Dept. of Immunology, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Toshiro Fujita
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Tokyo, Japan
| | - Tanya N. Mayadas
- Dept. of Pathology, Brigham and Women's Hospital & Harvard Medical School, Boston, Massachusetts
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Seshan SV, Franzke CW, Redecha P, Monestier M, Mackman N, Girardi G. Role of tissue factor in a mouse model of thrombotic microangiopathy induced by antiphospholipid antibodies. Blood 2009; 114:1675-83. [PMID: 19535796 DOI: 10.1182/blood-2009-01-199117] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using different mouse monoclonal and human antiphospholipid (aPL) antibodies, we developed a new animal model of renal injury that shares many features with thrombotic microangiopathy (TMA). We found that more than 1 mechanism/signaling pathway is involved in glomerular injury induced by aPL antibodies in this model. Both complement-dependent and complement-independent pathways were identified that lead to glomerular endothelial cell damage and renal function impairment. We also found that C5a-C5aR interaction is a crucial step for the activation of the coagulation cascade and glomerular injury induced by complement-activating antibodies. In addition, our studies demonstrated complement-independent mechanisms in which reactivity with beta(2) glycoprotein I (beta2GPI) plays an important role in aPL-induced glomerular damage and renal failure. Independently of the mechanism responsible for aPL-induced TMA, mice that express low levels of tissue factor (TF) were protected from glomerular injury. That genetic reduction of TF prevents renal injury induced by different aPL antibodies indicates that TF is a common mediator of glomerular damage and a possible target for selective pharmacologic intervention. Treatment with pravastatin, which down-regulates glomerular TF synthesis, prevents aPL-induced TMA in this mouse model, thus emphasizing that targeting TF might be a good therapeutic intervention in patients with TMA.
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Abstract
Complement fragment (C)5a is a 74 residue pro-inflammatory polypeptide produced during activation of the complement cascade of serum proteins in response to foreign surfaces such as microorganisms and tissue damaged by physical or chemical injury. C5a binds to at least two seven-transmembrane domain receptors, C5aR (C5R1, CD88) and C5L2 (gpr77), expressed ubiquitously on a wide variety of cells but particularly on the surface of immune cells like macrophages, neutrophils and T cells. C5aR is a classical G protein-coupled receptor that signals through G alpha i and G alpha 16, whereas C5L2 does not appear to couple to G proteins and has no known signalling activity. Although C5a was first described as an anaphylatoxin and later as a leukocyte chemoattractant, the widespread expression of C5aR suggested more general functionality. Our understanding of the physiology of C5a has improved significantly in recent years through exploitation of receptor knockout and knocking mice, C5 and C5a antibodies, soluble recombinant C5a and C5a analogues and newly developed receptor antagonists. C5a is now also implicated in non-immunological functions associated with developmental biology, CNS development and neurodegeneration, tissue regeneration, and haematopoiesis. Combined receptor mutagenesis, molecular modelling, structure-activity relationship studies and species dependence for ligand potency on C5aR have been helpful for identifying ligand binding sites on the receptor and for defining mechanisms of receptor activation and inactivation. This review will highlight major developments in C5a receptor research that support C5aR as an important therapeutic target. The intriguing possibilities raised by the existence of a non-signalling C5a receptor are also discussed.
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Affiliation(s)
- P N Monk
- Academic Neurology Unit, School of Medicine and Biomedical Science, University of Sheffield, Sheffield, UK.
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Mizuno M, Nozaki M, Morine N, Suzuki N, Nishikawa K, Morgan BP, Matsuo S. A protein toxin from the sea anemone Phyllodiscus semoni targets the kidney and causes a severe renal injury with predominant glomerular endothelial damage. Am J Pathol 2007; 171:402-14. [PMID: 17600120 PMCID: PMC1934535 DOI: 10.2353/ajpath.2007.060984] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Envenomation by the sea anemone Phyllodiscus semoni causes fulminant dermatitis and, rarely, acute renal failure in humans. Here, we investigated whether the venom extracted from the nematocysts (PsTX-T) was nephrotoxic when administered intravenously in rats and whether PsTX-T induced activation of the complement system. Although small dose of PsTX-T induced acute tubular necrosis in rats resembling pathology seen in patients, kidneys displayed glomerular injury with glomerular endothelial damage, thrombus formation, mesangiolysis, and partial rupture of glomerular basement membrane, accompanied by severe tubular necrosis at 24 hours after administration of 0.03 mg of PsTX-T per animal, similar to the glomerular findings typical of severe hemolytic uremic syndrome. The early stage injury was accompanied by specific PsTX-T binding, massive complement C3b, and membrane attack complex deposition in glomeruli in the regions of injury and decreased glomerular expression of complement regulators. A pathogenic role for complement was confirmed by demonstrating that systemic complement inhibition reduced renal injury. The isolated nephrotoxic component, a 115-kd protein toxin (PsTX-115), was shown to cause identical renal pathology. The demonstration that PsTX-T and PsTX-115 were highly nephrotoxic acting via induction of complement activation suggests that inhibition of complement might be used to prevent acute renal damage following envenomation by P. semoni.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Western
- CD55 Antigens/analysis
- CD59 Antigens/analysis
- Cnidarian Venoms/chemistry
- Cnidarian Venoms/metabolism
- Cnidarian Venoms/toxicity
- Complement Activation/drug effects
- Complement C3b/metabolism
- Complement Membrane Attack Complex/metabolism
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Endothelium/drug effects
- Endothelium/pathology
- Endothelium/ultrastructure
- Female
- Immunohistochemistry
- Kidney/drug effects
- Kidney/metabolism
- Kidney/pathology
- Kidney Glomerulus/drug effects
- Kidney Glomerulus/metabolism
- Kidney Glomerulus/pathology
- Mice
- Mice, Inbred BALB C
- Microscopy, Electron
- Protein Binding
- Rats
- Rats, Wistar
- Sea Anemones/chemistry
- Sequence Analysis, Protein
- Toxins, Biological/chemistry
- Toxins, Biological/metabolism
- Toxins, Biological/toxicity
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Affiliation(s)
- Masashi Mizuno
- Department of Nephrology, Nagoya University Graduate School of Medicine, Japan.
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16
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Romay-Penabad Z, Liu XX, Montiel-Manzano G, Papalardo De Martínez E, Pierangeli SS. C5a Receptor-Deficient Mice Are Protected from Thrombophilia and Endothelial Cell Activation Induced by Some Antiphospholipid Antibodies. Ann N Y Acad Sci 2007; 1108:554-66. [PMID: 17894020 DOI: 10.1196/annals.1422.058] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Recent findings indicate that complement activation--involving specifically C3 and C5--contributes to antiphospholipid (aPL)-mediated thrombosis. Two complement effector pathways are initiated by the cleavage of C5, C5a and C5b, which leads to the formation of the C5b-9 membrane attack complex. To delineate and distinguish the role of C5a from the C5b-9 membrane attack complex seeded by C5b, we examined the in vivo effects (thrombosis) of aPL on C5a receptor-deficient (C5aR-/-) mice. C5aR-/- and C5aR+/+ mice were injected with IgM or with IgG from two different patients with APS (IgM-APS or IgG-APS) or with control IgM or IgG (IgM-NHS or IgG-NHS) twice. Complement fixing activity of the Ig fractions and anticardiolipin activity in the sera of the mice were determined by enzyme-linked immunosorbent assay. Surgical procedures to study thrombus dynamics were performed. IgM-APS but not IgG-APS fixed C1q to cardiolipin-coated plates. IgM-APS significantly enhanced thrombus size in C5aR+/+ mice compared to C5aR+/+ mice treated with IgM-NHS (3198 +/- 2361 microm2 versus 585 +/- 460 microm2). C5aR-/- mice treated with IgM-APS showed a significant reduction in thrombi size as compared with C5aR+/+ mice (676 +/- 690 microm2 versus 3198 +/- 2361 microm2; P = 0.001). IgG-APS enhanced thrombus formation significantly in C5aR+/+ when compared to IgG-NHS-treated mice (3507 +/- 965 microm2 versus 1321 +/- 798 microm2), and these effects were not altered in C5aR-/- mice (3400 +/- 1681 microm2). The data indicate that C5aR-/- mice are protected from the thrombogenic effects of some aPL antibodies.
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Affiliation(s)
- Zurina Romay-Penabad
- Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas 77555-1165, USA
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17
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Abstract
The complement system is an important component of the innate immune system and a modulator of adaptive immunity. The entire complement system is focused on C3 and C5. Thus, there are proteins that activate C3 and C5, those that regulate this activation, and those that transduce the effects of C3 and C5 activation products; each can affect the kidney in renal injury. The normal kidney has the inherent capacity to protect itself from complement activation through cellular expression of decay-accelerating factor, membrane cofactor protein (in human beings), and Crry (in rodents). In addition, plasma factor H protects vascular spaces in the kidney. Although the main function of these proteins is to limit complement activation, there is now considerable evidence that they can transduce signals on engagement in immune cells. The G-protein-coupled 7-span transmembrane receptors for C3a and C5a, and the integral membrane complement receptors (CR) for C3b, iC3b, and C3dg, are expressed outside the kidney, particularly in cells of hematopoietic and immune lineage. These are important in renal injury through their infiltration of the kidney and/or by affecting kidney-directed immune responses. There is mounting evidence that intrinsic glomerular and tubular cell C3aR and C5aR expression and activation also can affect renal injury. CR1 on podocytes and the beta2 integrins CR3 and CR4 in kidney dendritic cells have functions that remain poorly defined. Cells of the kidney also have the capacity to produce and activate their own complement proteins. Thus, intrinsic renal cells express decay-accelerating factor, membrane cofactor protein, Crry, C3aR, C5aR, CR1, CR3, and CR4. These can be engaged by C3 and C5 activation products derived from systemic and local pools in renal injury. Given their capacity to provide signals that influence kidney cellular behavior, their activation can have substantial effects in renal injury. Defining these in a cell- and disease-specific fashion is an exciting challenge for future research.
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Affiliation(s)
- Tipu S Puri
- Section of Nephrology, University of Chicago, Chicago, IL 60637, USA
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18
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Finer G, Shalev H, Landau D. Genetic kidney diseases in the pediatric population of southern Israel. Pediatr Nephrol 2006; 21:910-6. [PMID: 16773401 DOI: 10.1007/s00467-006-0142-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 02/28/2006] [Accepted: 02/28/2006] [Indexed: 12/20/2022]
Abstract
Genetic kidney diseases (GKDs) are an important and well-known entity in pediatric nephrology. In the past decade advances in genetic and molecular approaches have enabled elucidation of the underlying molecular defects in many of these disorders. Herein we summarize the progress that has been made over the past decade in disclosing the molecular basis of several novel GKDs, which were characterized in our area and include Bartter syndrome type IV, type II Bartter syndrome and transient neonatal hyperkalemia, cystinuria and mental retardation, familial hypomagnesemia with secondary hypocalcemia, infantile nephronophthisis, familial hemolytic uremic syndrome with factor H deficiency, and non-cystic autosomal dominant nephropathy. Retrospective analysis of our data reveals that GKDs are over-represented among the pediatric population in southern Israel. GKDs are seen four-times more often than end-stage renal disease (ESRD) and comprise 38% of all cases of ESRD in our area. This high rate of GKDs is mainly due to the high frequency of consanguineous marriages that prevails in this area. Understanding of the genetic and molecular background of these diseases is a result of a fruitful collaboration between the pediatric nephrologists and scientists, and has a direct implication on the diagnosis and treatment of the affected families.
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Affiliation(s)
- Gal Finer
- Department of Pediatrics, Soroka University Medical Center, Ben-Gurion University of the Negev, P.O. Box 151, Beer-Sheva, 84101, Israel
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19
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Besbas N, Karpman D, Landau D, Loirat C, Proesmans W, Remuzzi G, Rizzoni G, Taylor CM, Van de Kar N, Zimmerhackl LB. A classification of hemolytic uremic syndrome and thrombotic thrombocytopenic purpura and related disorders. Kidney Int 2006; 70:423-31. [PMID: 16775594 DOI: 10.1038/sj.ki.5001581] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The diagnostic terms hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are based on historical and overlapping clinical descriptions. Advances in understanding some of the causes of the syndrome now permit many patients to be classified according to etiology. The increased precision of a diagnosis based on causation is important for considering logical approaches to treatment and prognosis. It is also essential for research. We propose a classification that accommodates both a current understanding of causation (level 1) and clinical association in cases for whom cause of disease is unclear (level 2). We tested the classification in a pediatric disease registry of HUS. The revised classification is a stimulus to comprehensive investigation of all cases of HUS and TTP and is expected to increase the proportion of cases in whom a level 1 etiological diagnosis is confirmed.
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Affiliation(s)
- N Besbas
- Hacettep University, Ankara, Turkey
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20
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21
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Pierangeli SS, Girardi G, Vega-Ostertag M, Liu X, Espinola RG, Salmon J. Requirement of activation of complement C3 and C5 for antiphospholipid antibody-mediated thrombophilia. ACTA ACUST UNITED AC 2005; 52:2120-4. [PMID: 15986360 DOI: 10.1002/art.21157] [Citation(s) in RCA: 274] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Antiphospholipid antibodies (aPL) have been shown to induce thrombosis, activate endothelial cells, and induce fetal loss. The pathogenesis of aPL-induced thrombosis, although not completely understood, may involve platelet and endothelial cell activation as well as procoagulant effects of aPL directly on clotting pathway components. Recent studies have shown that uncontrolled complement activation leads to fetal death in aPL-treated mice. In this study, we tested the hypothesis that aPL are responsible for activation of complement, thus generating split products that induce thrombosis. METHODS To study thrombus dynamics and adhesion of leukocytes we used in vivo murine models of thrombosis and microcirculation, in which injections of aPL were used. RESULTS Mice deficient in complement components C3 and C5 were resistant to the enhanced thrombosis and endothelial cell activation that was induced by aPL. Furthermore, inhibition of C5 activation using anti-C5 monoclonal antibodies prevented thrombophilia induced by aPL. CONCLUSION These data show that complement activation mediates 2 important effectors of aPL, induction of thrombosis and activation of endothelial cells.
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Affiliation(s)
- Silvia S Pierangeli
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA.
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22
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Abstract
Complement is part of the innate immune system, acting to protect the host from microorganisms such as bacteria, and other foreign and abnormal cells. Although primarily protective, complement activation can also cause damage to the host. In a number of inflammatory diseases, including rheumatoid arthritis and dermatitis, there is excessive and inappropriate complement activation. Many of the toxic effects seen in these conditions are attributable to the excessive production of the anaphylatoxin C5a, which may contribute to both the initiation and progression of the disease. Therefore, the regulation of C5a production and modulation of its function are good pharmacological targets in these disorders. As yet, there are no effective agents for the therapeutic regulation of C5a in routine clinical practice. This review describes the role of C5a in inflammatory disease, animal models used to study C5a-related effects, and current strategies aimed at regulating C5a. There is also a discussion of the strengths and weaknesses of these approaches, and an outline of the likely progress of this class of drugs in the future.
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Affiliation(s)
- Masashi Mizuno
- Department of Medical Biochemistry and Immunology, Cardiff University, School of Medicine, Henry Wellcome Building, Heath Park, Cardiff CF14 4XN, UK.
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23
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Abstract
Antiphospholipid antibodies (aPLs) have been shown to induce thrombosis, activate endothelial cells, and induce fetal loss. The pathogenesis of aPL-induced thrombosis is incompletely understood, but it is thought to involve platelet and endothelial cell activation as well as pro-coagulant effects of aPL antibody directly on clotting pathway components. Recent studies have shown that uncontrolled complement activation leads to fetal death in aPL-antibody treated mice. We hypothesized that aPL antibodies activate complement, generating split products that induce thrombosis. To test this hypothesis, we used an in vivo model of thrombosis in which aPL antibodies induce a significant increase in thrombus size and a mouse model of endothelial cell activation in which aPLs induce significant adhesion of leukocytes (WBCs) to endothelial cells. We found that mice deficient in complement components C3 and C5 were resistant to enhanced thrombosis and endothelial cell activation induced by aPL antibodies. Furthermore, inhibition of C5 activation using anti-C5 mAb prevented thrombophilia induced by aPL antibodies. Our data show that complement activation mediates two important effectors of aPL antibodies: induction of thrombosis and endothelial activation.
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Affiliation(s)
- Silvia S Pierangeli
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, 720 Westview Drive SW, Atlanta, GA 30310-1495, USA.
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24
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Fujita E, Farkas I, Campbell W, Baranyi L, Okada H, Okada N. Inactivation of C5a anaphylatoxin by a peptide that is complementary to a region of C5a. J Immunol 2004; 172:6382-7. [PMID: 15128829 DOI: 10.4049/jimmunol.172.10.6382] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PL37 (RAARISLGPRCIKAFTE) is an antisense homology box peptide composed of aa 37-53 of C5a-anaphylatoxin and is considered to be the region essential for C5a function. Using a computer program, we designed the complementary peptides ASGAPAPGPAGPLRPMF (Pep-A) and ASTAPARAGLPRLPKFF (Pep-B). Pep-A bound to PL37 and to C5a with very slow dissociation as determined by analysis using surface plasmon resonance, whereas Pep-B failed to bind at all. C5a was inactivated by concentrations of 7 nM or more of Pep-A, and this concentration of Pep-A inhibited induction of intracellular Ca(2+) influx in neutrophils. Patch clamp electrophysiology experiments also showed the effectiveness of Pep-A in C5aR-expressing neuroblastoma cells. Furthermore, Pep-A administration prevented rats from C5a-mediated rapid lethal shock induced by an Ab to a membrane inhibitor of complement after LPS sensitization.
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Affiliation(s)
- Emiko Fujita
- Department of Biodefense, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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25
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Girardi G, Berman J, Redecha P, Spruce L, Thurman JM, Kraus D, Hollmann TJ, Casali P, Caroll MC, Wetsel RA, Lambris JD, Holers VM, Salmon JE. Complement C5a receptors and neutrophils mediate fetal injury in the antiphospholipid syndrome. J Clin Invest 2003. [DOI: 10.1172/jci200318817] [Citation(s) in RCA: 488] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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26
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Girardi G, Berman J, Redecha P, Spruce L, Thurman JM, Kraus D, Hollmann TJ, Casali P, Caroll MC, Wetsel RA, Lambris JD, Holers VM, Salmon JE. Complement C5a receptors and neutrophils mediate fetal injury in the antiphospholipid syndrome. J Clin Invest 2003; 112:1644-54. [PMID: 14660741 PMCID: PMC281643 DOI: 10.1172/jci18817] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2003] [Accepted: 09/23/2003] [Indexed: 02/01/2023] Open
Abstract
Antiphospholipid syndrome (APS) is defined by recurrent pregnancy loss and thrombosis in the presence of antiphospholipid (aPL) Ab's. Currently, therapy for pregnant women with APS is focused on preventing thrombosis, but anticoagulation is only partially successful in averting miscarriage. We hypothesized that complement activation is a central mechanism of pregnancy loss in APS and tested this in a model in which pregnant mice receive human IgG containing aPL Ab's. Here we identify complement component C5 (and particularly its cleavage product C5a) and neutrophils as key mediators of fetal injury, and we show that Ab's or peptides that block C5a-C5a receptor interactions prevent pregnancy complications. The fact that F(ab)'2 fragments of aPL Ab's do not mediate fetal injury and that C4-deficient mice are protected from fetal injury suggests that activation of the complement cascade is initiated via the classical pathway. Studies in factor B-deficient mice, however, indicate that alternative pathway activation is required and amplifies complement activation. In contrast, activating Fc gamma Rs do not play an important role in mediating aPL Ab-induced fetal injury. Our findings identify the key innate immune effectors engaged by pathogenic autoantibodies that mediate poor pregnancy outcomes in APS and provide novel and important targets for prevention of pregnancy loss in APS.
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Affiliation(s)
- Guillermina Girardi
- Department of Medicine, Hospital for Special Surgery-Weill Medical College, Cornell University, 535 East 70th Street, New York, New York 10021, USA
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27
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Affiliation(s)
- V Michael Holers
- Department of Medicine and Immunology, Health Science Center, University of Colorado, Denver, CO 80262, USA.
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28
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Arumugam TV, Shiels IA, Strachan AJ, Abbenante G, Fairlie DP, Taylor SM. A small molecule C5a receptor antagonist protects kidneys from ischemia/reperfusion injury in rats. Kidney Int 2003; 63:134-42. [PMID: 12472776 DOI: 10.1046/j.1523-1755.2003.00737.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND C5a has been implicated in numerous pathophysiological conditions, including ischemia/reperfusion (I/R) injury of the kidney. We examined whether a novel and specific C5a receptor antagonist, the cyclic compound AcF-[OPdChaWR] could moderate I/R-induced renal injury in rats. METHODS Female Wistar rats were subjected to renal ischemia (60 min) and reperfusion (5 h). Rats were treated with either 1 mg/kg IV in 5% ethanol/saline or 10 mg/kg PO in 25% ethanol/saline prior to ischemia. I/R injury was characterized by significant tissue hemorrhage with increased microvascular permeability, elevated renal tissue levels of tumor necrosis factor-alpha (TNF-alpha) and myeloperoxidase (MPO), increased serum levels of creatinine and aspartate aminotransferase (AST) and hematuria. RESULTS Pre-ischemic treatment with the C5a receptor (C5aR) antagonist (1 mg/kg IV or 10 mg/kg PO) substantially inhibited or prevented I/R-induced hematuria, vascular leakage, tissue levels of TNF-alpha and MPO, and serum levels of AST and creatinine. Histological examination of kidneys from antagonist pretreated I/R animals showed a marked reduction in tissue damage compared to drug-free I/R rats. This antagonist, however, did not inhibit complement-mediated lysis of red blood cells, suggesting unimpaired formation of the membrane attack complex (MAC). CONCLUSIONS The results demonstrate for the first time that a selective antagonist of both human and rat C5a receptors, given either intravenously or orally, significantly protects the kidney from I/R injury in the rat. We conclude that C5a is an important pathogenic agent in renal I/R injury, and that C5a receptor antagonists may be useful therapeutic agents for the pretreatment of anticipated renal reperfusion injury in humans.
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Affiliation(s)
- Thiruma V Arumugam
- Department of Physiology and Pharmacology, School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
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29
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Sumichika H, Sakata K, Sato N, Takeshita S, Ishibuchi S, Nakamura M, Kamahori T, Ehara S, Itoh K, Ohtsuka T, Ohbora T, Mishina T, Komatsu H, Naka Y. Identification of a potent and orally active non-peptide C5a receptor antagonist. J Biol Chem 2002; 277:49403-7. [PMID: 12384495 DOI: 10.1074/jbc.m209672200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The anaphylatoxin C5a is a potent chemotactic factor for neutrophils and other leukocytes, and functions as an important inflammatory mediator. Through a high capacity screening followed by chemical optimization, we identified a novel non-peptide C5a receptor antagonist, N-[(4-dimethylaminophenyl)methyl]-N-(4-isopropylphenyl)-7-methoxy-1,2,3,4-tetrahydronaphthalen-1- carboxamide hydrochloride (W-54011). W-54011 inhibited the binding of (125)I-labeled C5a to human neutrophils with a K(i) value of 2.2 nm. W-54011 also inhibited C5a-induced intracellular Ca(2+) mobilization, chemotaxis, and generation of reactive super oxide species in human neutrophils with IC(50) values of 3.1, 2.7, and 1.6 nm, respectively. In C5a-induced intracellular Ca(2+) mobilization assay with human neutrophils, W-54011 did not show agonistic activity at up to 10 microm and shifted rightward the concentration-response curves to C5a without depressing the maximal responses. Examination on the species specificity of W-54011 revealed that it was able to inhibit C5a-induced intracellular Ca(2+) mobilization in neutrophils of cynomolgus monkeys and gerbils but not mice, rats, guinea pigs, rabbits, and dogs. In gerbils, oral administration of W-54011 (3-30 mg/kg) inhibited C5a-induced neutropenia in a dose-dependent manner. The present report is the first description of an orally active non-peptide C5a receptor antagonist that could contribute to the treatment of inflammatory diseases mediated by C5a.
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Affiliation(s)
- Hiroshi Sumichika
- Pharmaceuticals Research Division, Mitsubishi Pharma Co., 1000 Kamoshida-cho, Aoba-ku, Yokohama 227-0033, Japan.
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30
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Ikeguchi H, Maruyama S, Morita Y, Fujita Y, Kato T, Natori Y, Akatsu H, Campbell W, Okada N, Okada H, Yuzawa Y, Matsuo S. Effects of human soluble thrombomodulin on experimental glomerulonephritis. Kidney Int 2002; 61:490-501. [PMID: 11849389 DOI: 10.1046/j.1523-1755.2002.00160.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Coagulation and inflammation are both important processes that contribute to glomerular injury. The present study was performed to evaluate the effects of recombinant human soluble thrombomodulin (RHS-TM) in a lethal model of thrombotic glomerulonephritis and to investigate the possible mechanisms. METHODS Thrombotic glomerulonephritis was induced in rats by administration of lipopolysaccharide and rabbit anti-rat glomerular basement membrane antibody. One hour later, RHS-TM or heparin was administered, and the histological findings, renal functions, and coagulation parameters were evaluated. To evaluate the contribution of carboxypeptidase R (CPR) to the results obtained in rats treated with RHS-TM, plasma CPR levels were measured. Then, carboxypeptidase inhibitor (CPI), which prevents the function of CPR, was administered. RESULTS Massive glomerular thrombosis and lung hemorrhage developed within five hours of disease induction, and all rats died within 24 hours. RHS-TM (3 mg/kg) prevented the progression of the disease and all rats survived. Heparin (250 U/kg/h) showed similar anti-thrombotic effect, but induced massive hemorrhage in the lungs or stomach. RHS-TM attenuated leukocyte/neutrophil infiltration in the glomerulus but heparin did not, suggesting that RHS-TM has anti-inflammatory properties. CPR levels in plasma were about threefold higher in rats treated with RHS-TM compared to those in rats treated with heparin. Furthermore, the inhibitory effect of RHS-TM on leukocyte/neutrophil infiltration was significantly diminished by injection of CPI. CONCLUSION RHS-TM effectively attenuates the injuries of thrombotic glomerulonephritis in rats. The results indicate that RHS-TM, in addition to its anti-thrombotic action, may exert its anti-inflammatory properties by converting proCPR to CPR, which then inactivates anaphylatoxins. RHS-TM is a potential novel therapeutic tool for thrombotic glomerular injury and related disorders.
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Affiliation(s)
- Hiroshi Ikeguchi
- Internal Medicine III, Nagoya University School of Medicine, Nagoya, Japan
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