201
|
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.
Collapse
Affiliation(s)
- Andreas Klos
- Department for Medical Microbiology, Medical School Hannover, Hannover, Germany
| | | | | | | |
Collapse
|
202
|
Guo Q, Cheng J, Zhang H, Zhang J, Su B, Bian C, Lin S. Expressions of C5a and its receptor CD88 after spinal cord injury in C3-deficient mice. Scand J Immunol 2013; 77:224-9. [PMID: 23033813 DOI: 10.1111/sji.12001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 09/20/2012] [Indexed: 12/13/2022]
Abstract
The activation of complement system can aggravate the secondary injury after spinal cord injury (SCI). Our previous study indicates that the interception of complement activation by C3 deficiency can reduce the secondary injury and improve the regeneration and functional recovery after SCI. However, recently, it was reported that C5a which was generated during the complement activation pathways also had a protective effect on neurons, but whether it has the similar effect after SCI is unknown. To investigate the possibility and mechanism of the protective effect of C5a on neurons, it is necessary to study the expression profiles of C5a and its receptor CD88 after SCI and the influence on their expression when C3 was knocked out. By immunohistochemistry and Western blot, we found that in wild-type (WT) mice, both the expression of C5a and its receptor CD88 increased significantly, and there were two peaks during their expression after SCI. However, in C3-deficient mice, the expression of C5a still increased after SCI, although it was lower than that in WT group at every time points after SCI, and the expression of CD88 remained stable. Our study suggests that the expressions of C5a and CD88 can be inhibited in different degrees after SCI when the activation of complement system is blocked through C3 deficiency, which can reduce the secondary injury caused by C5a after SCI on one hand but deprive neurons of the possible protective effect from C5a on the other hand.
Collapse
Affiliation(s)
- Q Guo
- Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing, China.
| | | | | | | | | | | | | |
Collapse
|
203
|
Paradoxical glucose-sensitizing yet proinflammatory effects of acute ASP administration in mice. Mediators Inflamm 2013; 2013:713284. [PMID: 23737652 PMCID: PMC3666230 DOI: 10.1155/2013/713284] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/16/2013] [Accepted: 04/19/2013] [Indexed: 12/17/2022] Open
Abstract
Acylation stimulating protein (ASP) is an adipokine derived from the immune complement system, which stimulates fat storage and is typically increased in obesity, type 2 diabetes, and cardiovascular disease. Using a diet-induced obesity (DIO) mouse model, the acute effects of ASP on energy metabolism and inflammatory processes in vivo were evaluated. We hypothesized that ASP would specifically exert proinflammatory effects. C57Bl/6 wild-type mice were put on a high-fat-high-sucrose diet for 12 weeks. Mice were then subjected to both glucose and insulin tolerance tests, each manipulation being preceded by recombinant ASP or vehicle (control) bolus injection. ASP supplementation increased whole-body glucose excursion, and this was accomplished with reduced concomitant insulin levels. However, ASP did not directly alter insulin sensitivity. ASP supplementation induced a proinflammatory phenotype, with higher levels of cytokines including IL-6 and TNF-α in plasma and in adipose tissue, liver, and skeletal muscle mRNA. Additionally, ASP increased M1 macrophage content of these tissues. ASP exerted a direct concentration-dependent role in the migration and M1 activation of cultured macrophages. Altogether, the in vivo and in vitro experiments demonstrate that ASP plays a role in both energy metabolism and inflammation, with paradoxical whole-body glucose-sensitizing yet proinflammatory effects.
Collapse
|
204
|
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.
Collapse
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:
| |
Collapse
|
205
|
Abstract
Models of sepsis have been instructive in understanding the sequence of events in animals and, to an extent, in humans with sepsis. Events developing early in sepsis suggest that a hyperinflammatory state exists, accompanied by a buildup of oxidants in tissues reflective of a redox imbalance. Development of immunosuppression and degraded innate and adaptive immune responses are well-established complications of sepsis. In addition, there is robust activation of the complement system, which contributes to the harmful effects of sepsis. These events appear to be associated with development of multiorgan failure. The relevance of animal models of sepsis to human sepsis and the failure of human clinical trials are discussed, together with suggestions as to how clinical trial design might be improved.
Collapse
Affiliation(s)
- Peter A Ward
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA.
| |
Collapse
|
206
|
Deficiency of C5L2 increases macrophage infiltration and alters adipose tissue function in mice. PLoS One 2013; 8:e60795. [PMID: 23630572 PMCID: PMC3632610 DOI: 10.1371/journal.pone.0060795] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 03/03/2013] [Indexed: 12/22/2022] Open
Abstract
Background Obesity is considered as a systemic chronic low grade inflammation characterized by increased serum pro-inflammatory proteins and accumulation of macrophages within white adipose tissue (WAT) of obese patients. C5L2, a 7-transmembrane receptor, serves a dual function, binding the lipogenic hormone acylation stimulating protein (ASP), and C5a, involved in innate immunity. Aim We evaluated the impact of C5L2 on macrophage infiltration in WAT of wildtype (Ctl) and C5L2 knock-out (C5L2−/−) mice over 6, 12 and 24 weeks on a chow diet and moderate diet-induced obesity (DIO) conditions. Results In Ctl mice, WAT C5L2 and C5a receptor mRNA increased (up to 10-fold) both over time and with DIO. By contrast, in C5L2−/−, there was no change in C5aR in WAT. C5L2−/− mice displayed higher macrophage content in WAT, varying by time, fat depot and diet, associated with altered systemic and WAT cytokine patterns compared to Ctl mice. However, in all cases, the M1 (pro-) vs M2 (anti-inflammatory) macrophage proportion was unchanged but C5L2−/− adipose tissue secretome appeared to be more chemoattractant. Moreover, C5L2−/− mice have increased food intake, increased WAT, and altered WAT lipid gene expression, which is reflected systemically. Furthermore, C5L2−/− mice have altered glucose/insulin metabolism, adiponectin and insulin signalling gene expression in WAT, which could contribute to development of insulin resistance. Conclusion Disruption of C5L2 increases macrophage presence in WAT, contributing to obesity-associated pathologies, and further supports a dual role of complement in WAT. Understanding this effect of the complement system pathway could contribute to targeting treatment of obesity and its comorbidities.
Collapse
|
207
|
Chmilewsky F, Jeanneau C, Laurent P, Kirschfink M, About I. Pulp progenitor cell recruitment is selectively guided by a C5a gradient. J Dent Res 2013; 92:532-9. [PMID: 23603337 DOI: 10.1177/0022034513487377] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It recently became evident that activation of the complement system also contributes to tissue regeneration after infection/injury. The complement-derived fragment C5a induces vascular modifications and attracts cells expressing its receptor (C5aR/CD88) to the site of infection and tissue injury. Besides inflammatory cells, various tissue cells express this receptor. We hypothesized that pulp progenitor cells, being exposed to local complement activation in caries lesions, may respond to C5a via the C5aR. Our work aimed at evaluating the ability of C5a to induce pulp progenitor cell migration that may link complement activation to dentin regeneration. Immunofluorescence analysis of third molar pulp sections showed perivascular localization of the mesenchymal stem cell markers STRO-1 and C5aR. RT-PCR on STRO-1-sorted pulp progenitor cells, co-expressing both STRO-1 and C5aR, revealed high C5aR mRNA levels. Experiments with the C5aR antagonist W54011 revealed that C5a specifically bound to progenitor cells via C5aR, inducing their selective migration toward the C5a gradient. Since we could also demonstrate C5b-9 formation by immunohistochemistry in carious teeth, our findings suggest that, upon local complement activation, C5a induces pulp progenitor cell migration, which may be critical in initiating the regenerative process after dentin/pulp injury.
Collapse
Affiliation(s)
- F Chmilewsky
- Aix-Marseille Université, CNRS, ISM UMR 7287, 13288, Marseille cedex 09, France
| | | | | | | | | |
Collapse
|
208
|
Niwa T, Mizukoshi K, Azuma Y, Kashimata M, Shibutani T. Fundamental study of osteoclast chemotaxis toward chemoattractants expressed in periodontitis. J Periodontal Res 2013; 48:773-80. [PMID: 23586648 DOI: 10.1111/jre.12068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2013] [Indexed: 01/25/2023]
Abstract
BACKGROUND AND OBJECTIVE Periodontitis is a chronic inflammatory disease that leads to bone resorption by osteoclasts (OCs). Several factors contribute to the differentiation of OCs from hematopoietic precursors. Cellular chemotactic factors are expressed in periodontitis tissue, but the effects of these chemoattractants on OCs are not well understood. Here we examined the effects of chemoattractants produced in inflamed periodontal tissue on OC chemotaxis. MATERIAL AND METHODS Rat bone-marrow OCs were cultured in OC culture medium for 3 or 6 d. Using EZ-TAXIScan™, the chemotactic response of these OCs to several chemoattractants [monocyte chemotactic protein-1; macrophage inflammatory protein 1α; regulated on activation, normal T-cell expressed and secreted; stromal cell-derived factor-1α; and complement activation product 5a (C5a)] was measured. In addition, we measured the effect of C5a-specific inhibitors on chemotactic responses toward C5a. The recorded chemotactic responses were quantitatively analysed using ImageJ software. RESULTS Chemoattractants associated with periodontal disease significantly increased the chemotactic activity of differentiated rat OCs in a concentration-dependent manner, with C5a inducing the highest chemotactic activity of OCs cultured for 3 or 6 d. The C5a-specific inhibitor significantly inhibited chemotaxis toward C5a in a concentration-dependent manner. CONCLUSION We suggest that C5a plays an important role in pathologic bone resorption in periodontal disease by stimulating the chemotaxis of OCs. Therefore, C5a is a potential target for the treatment of periodontal disease.
Collapse
Affiliation(s)
- T Niwa
- Department of Periodontology, Division of Oral Infections and Health Sciences, Asahi University School of Dentistry, Mizuho, Japan
| | | | | | | | | |
Collapse
|
209
|
van Werkhoven MB, Damman J, van Dijk MCRF, Daha MR, de Jong IJ, Leliveld A, Krikke C, Leuvenink HG, van Goor H, van Son WJ, Olinga P, Hillebrands JL, Seelen MAJ. Complement mediated renal inflammation induced by donor brain death: role of renal C5a-C5aR interaction. Am J Transplant 2013; 13:875-882. [PMID: 23398742 DOI: 10.1111/ajt.12130] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 11/26/2012] [Accepted: 12/10/2012] [Indexed: 01/25/2023]
Abstract
Kidneys retrieved from brain-dead donors have impaired allograft function after transplantation compared to kidneys from living donors. Donor brain death (BD) triggers inflammatory responses, including both systemic and local complement activation. The mechanism by which systemic activated complement contributes to allograft injury remains to be elucidated. The aim of this study was to investigate systemic C5a release after BD in human donors and direct effects of C5a on human renal tissue. C5a levels were measured in plasma from living and brain-dead donors. Renal C5aR gene and protein expression in living and brain-dead donors was investigated in renal pretransplantation biopsies. The direct effect of C5a on human renal tissue was investigated by stimulating human kidney slices with C5a using a newly developed precision-cut method. Elevated C5a levels were found in plasma from brain-dead donors in concert with induced C5aR expression in donor kidney biopsies. Exposure of precision-cut human kidney slices to C5a induced gene expression of pro-inflammatory cytokines IL-1 beta, IL-6 and IL-8. In conclusion, these findings suggest that systemic generation of C5a mediates renal inflammation in brain-dead donor grafts via tubular C5a-C5aR interaction. This study also introduces a novel in vitro technique to analyze renal cells in their biological environment.
Collapse
Affiliation(s)
- M B van Werkhoven
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - J Damman
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - M C R F van Dijk
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - M R Daha
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.,Department of Nephrology, Leiden University Medical Center, Leiden, the Netherlands
| | - I J de Jong
- Department of Urology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - A Leliveld
- Department of Urology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - C Krikke
- Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - H G Leuvenink
- Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - H van Goor
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - W J van Son
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - P Olinga
- Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, Groningen Research Institute of Pharmacy, Groningen, the Netherlands
| | - J-L Hillebrands
- Department of Pathology and Medical Biology, Division of Pathology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - M A J Seelen
- Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| |
Collapse
|
210
|
Mueller M, Herzog C, Larmann J, Schmitz M, Hilfiker-Kleiner D, Gessner JE, Theilmeier G. The receptor for activated complement factor 5 (C5aR) conveys myocardial ischemic damage by mediating neutrophil transmigration. Immunobiology 2013; 218:1131-8. [PMID: 23642836 DOI: 10.1016/j.imbio.2013.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 03/14/2013] [Accepted: 03/21/2013] [Indexed: 01/23/2023]
Abstract
Tissue loss after myocardial ischemia with reperfusion (MI/R) is in part conveyed by neutrophil recruitment to post-ischemic myocardium. Strategies to prevent reperfusion injury would help to limit myocardial damage. The receptor for activated complement factor 5 (C5aR) plays a prominent role in inflammation. We examine the effects of C5aR-deficiency on reperfusion injury after MI/R. C5aR(-/-)-mice and their C57BL/6- (WT) littermates underwent transient myocardial ischemia followed by different time points of reperfusion. Infarct size and leukocyte infiltration were determined. Expression of C5aR, inflammatory cytokines and adhesion molecules were analyzed by real-time RT-PCR. Leukocyte-endothelial interactions were assessed by low-shear adhesion- and transmigration-assays in vitro. Myocardial C5aR mRNA expression was 2.8-fold increased by ischemia. Infarct size per area-at-risk and leukocyte recruitment into infarctions were reduced in C5aR(-/-)-compared to WT-mice as well as in WT mice treated with the C5aR-antagonist JPE1375. IL-6, IL-1β, ICAM-1 and VCAM-1 expression were not different, while TNFα expression was reduced in C5aR(-/-)-mice after MI/R. In vitro, C5aR on leukocytes is required for effective transendothelial migration but not adhesion. Expression of MMP9 and JAM-A, molecules that are involved in leukocyte transmigration, were reduced in C5aR(-/-) mice in vivo. Genetic C5aR deficiency blunts the inflammatory response in murine MI/R resulting in reduced inflammatory cell recruitment, which is due to a C5aR-dependent effect on leukocyte transmigration across inflamed endothelium into the ischemic myocardium. This effect could be related to MMP9- and JAM-A expression in response to ischemia and reperfusion.
Collapse
Affiliation(s)
- Martin Mueller
- Department of Anesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany
| | | | | | | | | | | | | |
Collapse
|
211
|
van Werkhoven MB, Damman J, Daha MR, Krikke C, van Goor H, van Son WJ, Hillebrands JL, van Dijk MC, Seelen MA. Novel insights in localization and expression levels of C5aR and C5L2 under native and post-transplant conditions in the kidney. Mol Immunol 2013; 53:237-45. [DOI: 10.1016/j.molimm.2012.08.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/08/2012] [Accepted: 08/13/2012] [Indexed: 10/27/2022]
|
212
|
Fonseca MI, McGuire SO, Counts SE, Tenner AJ. Complement activation fragment C5a receptors, CD88 and C5L2, are associated with neurofibrillary pathology. J Neuroinflammation 2013; 10:25. [PMID: 23394121 PMCID: PMC3605123 DOI: 10.1186/1742-2094-10-25] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 01/28/2013] [Indexed: 12/30/2022] Open
Abstract
Background Alzheimer’s disease (AD) is a neurodegenerative dementia characterized by the decline of cognition and the presence of neuropathological changes including neuronal loss, neurofibrillary pathology and extracellular senile plaques. A neuroinflammatory process is also triggered and complement activation has been hypothesized to have a relevant role in this local inflammatory response. C5a, a proinflammatory anaphylatoxin generated after complement activation, exerts its chemotactic and inflammatory functions through the CD88 receptor while the more recently discovered C5L2 receptor has been postulated to have an anti-inflammatory role. Previously, we reported that a CD88 specific antagonist (PMX205) decreased the pathology and improved cognition in transgenic models of AD suggesting that C5a/C5aR interaction has an important role in the progression of the disease. Methods The present study characterizes the expression of the two receptors for C5a in human brain with confirmed post mortem diagnosis of vascular dementia (VD) or AD as well as age matched controls by immunohistochemistry and Western blot analysis using several antibodies against different epitopes of the human receptors. Results The CD88 and C5L2 antibodies revealed increased expression of both receptors in AD samples as compared to age-matched controls or VD brain tissue by Western blot and immunohistochemistry, using multiple antibodies and distinct cohorts of brain tissue. Immunostaining showed that both the C5L2 and CD88 antibodies similarly labeled abundant neurofibrillary tangles, neuropil threads and dystrophic neurites associated with plaques in the hippocampus and frontal cortex of AD cases. In contrast, little or no neuronal staining, tangles or dystrophic neurites associated with plaques were observed in control or VD brains. CD88 and C5L2 receptors are associated with both early (AT8) and mature (PHF1) neurofibrillary tangles and can be found either independently or colocalized with each other. Conclusions The observed association of CD88 and C5L2 with neurofibrillary pathology suggests a common altered pathway of degradation.
Collapse
Affiliation(s)
- Maria I Fonseca
- Dept of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | | | | | | |
Collapse
|
213
|
Kidd LJ, Cowling NR, Wu AC, Kelly WL, Forwood MR. Selective and non-selective cyclooxygenase inhibitors delay stress fracture healing in the rat ulna. J Orthop Res 2013; 31:235-42. [PMID: 22847634 DOI: 10.1002/jor.22203] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 07/09/2012] [Indexed: 02/04/2023]
Abstract
Anti-inflammatory drugs are widely used to manage pain associated with stress fractures (SFxs), but little is known about their effects on healing of those injuries. We hypothesized that selective and non-selective anti-inflammatory treatments would retard the healing of SFx in the rat ulna. SFxs were created by cyclic loading of the ulna in Wistar rats. Ulnae were harvested 2, 4 or 6 weeks following loading. Rats were treated with non-selective NSAID, ibuprofen (30 mg/kg/day); selective COX-2 inhibition, [5,5-dimethyl-3-3 (3 fluorophenyl)-4-(4 methylsulfonal) phenyl-2 (5H)-furanone] (DFU) (2.0 mg/kg/day); or the novel c5a anatagonist PMX53 (10 mg/kg/day, 4 and 6 weeks only); with appropriate vehicle as control. Quantitative histomorphometric measurements of SFx healing were undertaken. Treatment with the selective COX-2 inhibitor, DFU, reduced the area of resorption along the fracture line at 2 weeks, without affecting bone formation at later stages. Treatment with the non-selective, NSAID, ibuprofen decreased both bone resorption and bone formation so that there was significantly reduced length and area of remodeling and lamellar bone formation within the remodeling unit at 6 weeks after fracture. The C5a receptor antagonist PMX53 had no effect on SFx healing at 4 or 6 weeks after loading, suggesting that PMX53 would not delay SFx healing. Both selective COX-2 inhibitors and non-selective NSAIDs have the potential to compromise SFx healing, and should be used with caution when SFx is diagnosed or suspected.
Collapse
Affiliation(s)
- Lisa J Kidd
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia
| | | | | | | | | |
Collapse
|
214
|
Qing XY, Zhang CH, Li LL, Ji P, Ma S, Wan HL, Wang ZR, Zou J, Yang SY. Retrieving novel C5aR antagonists using a hybrid ligand-based virtual screening protocol based on SVM classification and pharmacophore models. J Biomol Struct Dyn 2013; 31:215-23. [DOI: 10.1080/07391102.2012.698245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
215
|
Nishiura H. The alternative C5a receptor function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 735:111-21. [PMID: 23402022 DOI: 10.1007/978-1-4614-4118-2_7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
When acute inflammatory states are induced by treatment with chemical mediators in C5-deficient mice, neutrophil influxes are commonly decreased. Therefore, the neutrophil C5a receptor (C5aR) is believed to be a member of the pro-inflammatory receptors. However, C5aR deficiency endows mouse neutrophils with increased sensitivity to Pseudomonas aeruginosa. We have demonstrated that C5aR accepts not only C5a but also ribosomal protein S19 (RP S19) oligomers. RP S19 oligomers released from apoptotic cells promote apoptosis or induce dual agonistic and antagonistic effects on the chemotaxis of macrophages and neutrophils in an autocrine or paracrine manner, respectively. We assumed that the function of C5aR in apoptotic cells is almost the same as that in neutrophils infiltrating acute inflammatory lesions. Therefore, we believe that RP S19 oligomers can explain the opposite response of neutrophils in C5aR-deficient mice. In the present study, we found that antihuman RP S19 rabbit IgG cross-reacted with mouse RP S19 monomers and oligomers in plasma and serum, respectively, whereas anti-human C5a rabbit IgG only cross-reacted with mouse RP S19 oligomers in serum. To examine a role of RP S19 oligomers in vivo, we injected carrageenan (50 microg/100 microL) into the thoracic cavities of mice in the simultaneous presence of rabbit IgG and antihuman C5a rabbit IgG (100 microg/100 microL). Before 4 h and after 24 h, we did not observe any inflammatory cues in pleural exudates and lung substances from control mice. However, infiltrating neutrophils were detected in pleural exudates and lung tissues at 4 h after the addition of anti-human RP S19 rabbit IgG. Moreover, anti-human C5a rabbit IgG retards the initiation phase of carrageenan-induced mouse plurality. Many of the neutrophils infiltrating the thoracic cavities of the mice remained annexin V-negative. Neutrophil infiltration into pneumonic lesions became more severe, as alveolar septal destruction and haemorrhage concomitant with increased numbers of neutrophils in the pleural exudates were observed. These in vivo data demonstrate that the neutrophil C5aR acts as a dual pro-inflammatory and pro-apoptosis receptor during the initiation and the resolution phases of acute inflammation, respectively.
Collapse
Affiliation(s)
- Hiroshi Nishiura
- Department of Molecular Pathology, Kumamoto University Graduate School, Honjyo 1-1-1, Kumamoto 860-8556, Japan.
| |
Collapse
|
216
|
|
217
|
Progress and Trends in Complement Therapeutics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 735:1-22. [PMID: 22990692 DOI: 10.1007/978-1-4614-4118-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The past few years have proven to be a highly successful and exciting period for the field of complement-directed drug discovery and development. Driven by promising experiences with the first marketed complement drugs, increased knowledge about the involvement of complement in health and disease, and improvements in structural and analytical techniques as well as animal models of disease, the field has seen a surge in creative approaches to therapeutically intervene at various stages of the cascade. An impressive panel of compounds that show promise in clinical trials is meanwhile being lined up in the pipelines of both small biotechnology and big pharmaceutical companies. Yet with this new focus on complement-targeted therapeutics, important questions concerning target selection, point and length of intervention, safety, and drug delivery emerge. In view of the diversity of the clinical disorders involving abnormal complement activity or regulation, which include both acute and chronic diseases and affect a wide range of organs, diverse yet specifically tailored therapeutic approaches may be needed to shift complement back into balance. This chapter highlights the key changes in the field that shape our current perception of complement-targeted drugs and provides a brief overview of recent strategies and emerging trends. Selected examples of complement-related diseases and inhibitor classes are highlighted to illustrate the diversity and creativity in field.
Collapse
|
218
|
Dual functions of the C5a receptor as a connector for the K562 erythroblast-like cell-THP-1 macrophage-like cell island and as a sensor for the differentiation of the K562 erythroblast-like cell during haemin-induced erythropoiesis. Clin Dev Immunol 2012; 2012:187080. [PMID: 23346183 PMCID: PMC3546471 DOI: 10.1155/2012/187080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/18/2012] [Accepted: 11/11/2012] [Indexed: 12/22/2022]
Abstract
The transcriptional nuclear factor binding to the Y box of human leukocyte antigen genes (NF-Y) for the C5a receptor (C5aR) gene is active in erythroblasts. However, the roles of the C5aR in erythropoiesis are unclear. We have previously demonstrated that apoptotic cell-derived ribosomal protein S19 (RP S19) oligomers exhibit extraribosomal functions in promoting monocyte chemotaxis and proapoptosis via the C5aR without receptor internalisation. In contrast to the extraribosomal functions of the RP S19, a proapoptotic signal in pro-EBs, which is caused by mutations in the RP S19 gene, is associated with the inherited erythroblastopenia, Diamond-Blackfan anaemia. In this study, we detected C5aR expression and RP S19 oligomer generation in human erythroleukemia K562 cells during haemin-induced erythropoiesis. Under monocell culture conditions, the differentiation into K562 erythrocyte-like cells was enhanced following the overexpression of Wild-type RP S19. Conversely, the differentiation was repressed following the overexpression of mutant RP S19. An RP S19 oligomer inhibitor and a C5aR inhibitor blocked the association of the K562 basophilic EB-like cells and the THP-1 macrophage-like cells under coculture conditions. When bound to RP S19 oligomers, the C5aR may exhibit dual functions as a connector for the EB-macrophage island and as a sensor for EB differentiation in the bone marrow.
Collapse
|
219
|
Li R, Coulthard LG, Wu MCL, Taylor SM, Woodruff TM. C5L2: a controversial receptor of complement anaphylatoxin, C5a. FASEB J 2012; 27:855-64. [PMID: 23239822 DOI: 10.1096/fj.12-220509] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
C5a is the paramount proinflammatory mediator of the complement cascade, and has been previously thought to act only through a single, G-protein-coupled, C5a receptor (C5aR; also termed CD88). In 2000, a second C5a receptor, C5L2 (previously known as GPR77), was discovered; yet, despite 12 yr of intensive research, its biological, or pathophysiological, function is both enigmatic and controversial. Unlike C5aR, this receptor does not couple to G proteins, and early studies promoted the hypothesis that C5L2 functions as a decoy receptor. However, recent data have provided other evidence for more complicated and conflicting interactions between C5L2 and other inflammatory mediators. C5L2 has been recently demonstrated to physically interact with both C5aR and β-arrestin to negatively regulate C5aR signaling toward an anti-inflammatory manner, and to reduce pathology, in several disease models in vivo. In direct contrast, other groups have demonstrated that C5L2 stimulation caused release of HMGB1 both in vitro and in vivo, and enhanced pathology in sepsis models, suggesting a clear proinflammatory signaling role. These astoundingly contradictory data challenge our precepts and complicate the foundational bases for the possible targeting of C5L2 as a therapeutic option in inflammatory disease. C5L2 may be the great masquerader in complement biology; its function dependent on the cell type, species, and disease context. Because of these unusual and unforeseen complexities, we present the current state of knowledge on C5L2 structure, expression and, most controversially, its putative functions.-Li, R., Coulthard, L.G., Wu, M. C. L., Taylor, S. M., Woodruff, T. M. C5L2: a controversial receptor of complement anaphylatoxin, C5a.
Collapse
Affiliation(s)
- Rui Li
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD, 4072, Australia
| | | | | | | | | |
Collapse
|
220
|
Nuutila J, Jalava-Karvinen P, Hohenthal U, Kotilainen P, Pelliniemi TT, Nikoskelainen J, Lilius EM. A rapid flow cytometric method for distinguishing between febrile bacterial and viral infections. J Microbiol Methods 2012; 92:64-72. [PMID: 23154042 DOI: 10.1016/j.mimet.2012.11.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 11/02/2012] [Accepted: 11/05/2012] [Indexed: 11/26/2022]
Abstract
Antibiotic resistance due to the inappropriate use of antimicrobials is one of the most critical public health problems worldwide. A major factor underlying the unnecessary use of antibiotics is the lack of rapid and accurate diagnostic tests. Therefore, we aimed to develop a novel rapid flow cytometric method for distinguishing between febrile bacterial and viral infections. In this prospective comparative study, quantitative flow cytometric analysis of FcγRII/CD32, CR1/CD35, MHC Class I receptor (MHCI), and C5aR/CD88 on human phagocytes was performed in 286 hospitalized febrile patients with suspected infection. After using microbiological and serological detection methods, or clinical diagnosis, 205 patients were identified with either bacterial (n=136) or viral (n=69) infection. Receptor data from patients were compared to those of 50 healthy controls. We developed a flow cytometric marker of local and systemic bacterial infections designated "bacterial infection score (BIS)" incorporating the quantitative analysis of FcγRII/CD32, CR1/CD35, C5aR/CD88 and MHCI on neutrophils and/or monocytes, which displays 91% sensitivity and 92% specificity in distinguishing between microbiologically confirmed bacterial (n=77) and serologically confirmed viral infections (n=61) within 1h. The BIS method was effectively applied to distinguish between bacterial and viral (pandemic H1N1 influenza) pneumonia cases with 96% sensitivity and 92% specificity. We propose that the rapid BIS test can assist physicians in deciding whether antibiotic treatment is necessary, thus reducing unnecessary antimicrobial use.
Collapse
Affiliation(s)
- Jari Nuutila
- Department of Biochemistry, University of Turku, Turku, Finland.
| | | | | | | | | | | | | |
Collapse
|
221
|
Lim J, Iyer A, Suen JY, Seow V, Reid RC, Brown L, Fairlie DP. C5aR and C3aR antagonists each inhibit diet-induced obesity, metabolic dysfunction, and adipocyte and macrophage signaling. FASEB J 2012; 27:822-31. [PMID: 23118029 DOI: 10.1096/fj.12-220582] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mammalian survival depends on metabolizing nutrients, storing energy, and combating infection. Complement activation in blood triggers energy-depleting immune responses to fight infections. Here we identify surprising energy-conserving roles for complement proteins C5a and C3a and their receptors, C5aR and C3aR, roles that are contraindicated in complement biology. Rats fed a high-carbohydrate high-fat diet developed obesity, visceral adiposity, adipose inflammation, glucose/insulin intolerance, and cardiovascular dysfunction that correlated with increased plasma C3a, adipose C5aR, and C3aR. These in vivo changes were dramatically attenuated by receptor-selective antagonists of either C5aR (5 mg/kg/d p.o.) or C3aR (30 mg/kg/d p.o.), which both reduced proinflammatory adipokines and altered expression of inflammatory genes in adipose tissue. In vitro C5a and C3a (100 nM) exhibited novel insulin-like effects on 3T3-L1 adipocytes, promoting energy conservation by increasing glucose and fatty acid uptake while inhibiting cAMP signaling and lipolysis, and induced PGE(2) release from macrophages, effects all blocked by each respective antagonist (10 μM). These studies reveal important new links between complement signaling and metabolism, highlight new complement functions on adipocytes and in adipose tissue, demonstrate how aberrant immune responses may exacerbate obesity and metabolic dysfunction, and show that targeting C3aR or C5aR with antagonists is a new strategy for treating metabolic dysfunction.
Collapse
Affiliation(s)
- Junxian Lim
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | | | | | | | | | | | | |
Collapse
|
222
|
Reis ES, Chen H, Sfyroera G, Monk PN, Köhl J, Ricklin D, Lambris JD. C5a receptor-dependent cell activation by physiological concentrations of desarginated C5a: insights from a novel label-free cellular assay. THE JOURNAL OF IMMUNOLOGY 2012; 189:4797-805. [PMID: 23041570 DOI: 10.4049/jimmunol.1200834] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The complement anaphylatoxins C3a, C5a, and desarginated C5a (C5a(desArg)) play critical roles in the induction of inflammation and the modulation of innate and acquired immune responses after binding to their G protein-coupled receptors, C3a receptor and C5a receptor (C5aR). The role of C5a(desArg) in inducing cell activation has been often neglected, because the affinity of C5a(desArg) for C5aR has been reported to be much lower than that of C5a. We have used a novel label-free cellular assay to reassess the potential of C5a(desArg) to induce activation of transfected and primary immune cells. Our results indicate that physiological levels of C5a(desArg) induce significant levels of cell activation that are even higher than those achieved by stimulating cells with analogous concentrations of C5a. Such activation was strictly dependent on C5aR, because it was completely abrogated by PMX-53, a C5aR antagonist. Pharmacological inhibition of specific G proteins located downstream of C5aR indicated differential involvement of G(α) proteins upon C5aR engagement by C5a or C5a(desArg). Further, mass spectrometric characterization of plasma-derived C5a and C5a(desArg) provided important insight into the posttranslational modification pattern of these anaphylatoxins, which includes glycosylation at Asn(64) and partial cysteinylation at Cys(27). Although the context-specific physiological contribution of C5a(desArg) has to be further explored, our data suggest that C5a(desArg) acts as a key molecule in the triggering of local inflammation as well as the maintenance of blood surveillance and homeostatic status.
Collapse
Affiliation(s)
- Edimara S Reis
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | |
Collapse
|
223
|
Schulze-Tanzil G, Kohl B, El Sayed K, Arens S, Ertel W, Stölzel K, John T. Anaphylatoxin receptors and complement regulatory proteins in human articular and non-articular chondrocytes: interrelation with cytokines. Cell Tissue Res 2012; 350:465-75. [PMID: 23053049 DOI: 10.1007/s00441-012-1497-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 08/27/2012] [Indexed: 12/13/2022]
Abstract
Tissue trauma induces an inflammatory response associated with a cytokine release that may engage complement pathways. Cytokine-mediated complement expression may contribute to cartilage degradation. Hence, we analysed the complement expression profile in primary articular and non-articular chondrocytes and its interrelation with cytokines. The expression of the anaphylatoxin receptors (C3aR and C5aR) and the complement regulatory proteins (CPRs) CD35, CD46, CD55 and CD59 was studied in cultured articular, auricular and nasoseptal chondrocytes using RTD-PCR and immunofluorescence labelling. The complement profile of peripheral blood mononuclear cells (PBMCs) was opposed to the expression in articular chondrocytes. The time-dependent regulation (6 and 24 h) of these complement factors was assessed in articular chondrocytes in response to the cytokines TNFα, IL-10 or TNFα combined with IL-10 (each 10 ng/mL). C3aR, C5aR, CD46, CD55 and CD59 but almost no CD35 mRNA was expressed in any of chondrocyte types studied. The anaphylatoxin receptor expression was lower and that of the CRPs was higher in chondrocytes when compared with PBMCs. The majority of the studied complement factors were expressed at a significantly lower level in non-articular chondrocytes compared with the articular chondrocytes. TNFα significantly increased the C3aR expression in chondrocytes after 6 and 24 h. TNFα + IL-10 significantly downregulated C5aR and IL-10 significantly inhibited the CD46 and CD55 gene expression after 24 h. C5aR and CD55 could be localised in cartilage in situ. Anaphylatoxin receptors and CRPs are regulated differentially by TNFα and IL-10. Whether cytokine-induced complement activation occurs in response to cartilage trauma has to be further identified.
Collapse
Affiliation(s)
- Gundula Schulze-Tanzil
- Department of Orthopedic, Trauma and Reconstructive Surgery, Charité-Universitätsmedizin, Campus Benjamin Franklin, Berlin, Germany.
| | | | | | | | | | | | | |
Collapse
|
224
|
Moghimi SM, Wibroe PP, Helvig SY, Farhangrazi ZS, Hunter AC. Genomic perspectives in inter-individual adverse responses following nanomedicine administration: The way forward. Adv Drug Deliv Rev 2012; 64:1385-93. [PMID: 22634158 DOI: 10.1016/j.addr.2012.05.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 05/17/2012] [Indexed: 01/18/2023]
Abstract
The underlying mechanism of intravenous infusion-related adverse reactions inherent to regulatory-approved nanomedicines still remains elusive. There are substantial inter-individual differences in observed adverse reactions, which may include cardiovascular, broncho-pulmonary, muco-cutaneous, neuro-psychosomatic and autonomic manifestations. Although nanomedicine-mediated triggering of complement activation has been suggested to be a significant contributing factor to these adverse events, complement activation may still proceed in non-responders. Whether these reactions share similar immunological mechanisms and underpinning genetic factors with drug hypersensitivity syndrome remains to be investigated. Genetic association studies could be a powerful tool to dissect causative factors and reveal the multiple molecular pathways that induce infusion related adverse reactions. It is envisaged that such research may lead to the design of reliable in vitro profiling tests for risk assessment and treatment decisions, thereby revolutionizing the practice of medicine with nanopharmaceuticals. Such procedures may further improve regulatory approval processes for nanomedicines currently in the pipeline and decrease the overall cost of health care. Here we discuss some key innate immunity genes and their polymorphisms in relation to nanomedicine infusion-mediated symptomatic responses.
Collapse
Affiliation(s)
- S Moein Moghimi
- Centre for Pharmaceutical Nanotechnology and Nanotoxicology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark.
| | | | | | | | | |
Collapse
|
225
|
van den Berg CW, Gonçalves-de-Andrade RM, Okamoto CK, Tambourgi DV. C5a receptor is cleaved by metalloproteases induced by sphingomyelinase D from Loxosceles spider venom. Immunobiology 2012; 217:935-41. [DOI: 10.1016/j.imbio.2012.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 01/04/2012] [Accepted: 01/04/2012] [Indexed: 11/28/2022]
|
226
|
Abstract
Complement activation usually results in the formation of complement fragment 5a (C5a) that interacts with its two receptors, C5aR and C5L2. These receptors belong to the rhodopsin family of G protein-coupled seven transmembrane-containing receptors. C5aR and C5L2 are expressed on/in a wide variety of cells and tissues. Interaction of C5a with C5aR leads to many pleiotropic effects, including the release of cytokines and chemokines and recruitment of inflammatory cells. In certain circumstances, C5a-C5aR interactions can also result in pathophysiological changes as seen in sepsis, rheumatoid arthritis, asthma, acute lung injury and ischemia-reperfusion injury. This overview of the C5a-C5aR interactions describes how such interactions facilitate the pivotal role the complement system plays in the host's innate and adaptive responses.
Collapse
Affiliation(s)
- J Vidya Sarma
- University of Michigan Medical School, Department of Pathology, Ann Arbor, MI, USA
| | | |
Collapse
|
227
|
Halai R, Croker DE, Suen JY, Fairlie DP, Cooper MA. A Comparative Study of Impedance versus Optical Label-Free Systems Relative to Labelled Assays in a Predominantly Gi Coupled GPCR (C5aR) Signalling. BIOSENSORS 2012; 2:273-90. [PMID: 25585930 PMCID: PMC4263554 DOI: 10.3390/bios2030273] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/11/2012] [Accepted: 07/24/2012] [Indexed: 12/18/2022]
Abstract
Profiling ligand function on G-protein coupled receptors (GPCRs) typically involves using transfected cells over-expressing a target of interest, a labelled ligand, and intracellular secondary messenger reporters. In contrast, label-free assays are sensitive enough to allow detection in native cells, which may provide a more physiologically relevant readout. Here, we compare four agonists (native agonists, a peptide full agonist and a peptide partial agonist) that stimulate the human inflammatory GPCR C5aR. The receptor was challenged when present in human monocyte-derived macrophages (HMDM) versus stably transfected human C5aR-CHO cells. Receptor activation was compared on label-free optical and impedance biosensors and contrasted with results from two traditional reporter assays. The rank order of potencies observed across label-free and pathway specific assays was similar. However, label-free read outs gave consistently lower potency values in both native and transfected cells. Relative to pathway-specific assays, these technologies measure whole-cell responses that may encompass multiple signalling events, including down-regulatory events, which may explain the potency discrepancies observed. These observations have important implications for screening compound libraries against GPCR targets and for selecting drug candidates for in vivo assays.
Collapse
Affiliation(s)
- Reena Halai
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Daniel E Croker
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Jacky Y Suen
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - David P Fairlie
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| | - Matthew A Cooper
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
| |
Collapse
|
228
|
Smith SG, Watson B, Clark G, Gauvreau GM. Eculizumab for treatment of asthma. Expert Opin Biol Ther 2012; 12:529-37. [PMID: 22413827 DOI: 10.1517/14712598.2012.668517] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Asthma is an inflammatory disease, which can be exacerbated by stimuli such as viral infections and exposure to allergens. Asthma continues to be a profound public health problem due to asthma exacerbation in a low proportion of patients in need of more effective medications. AREAS COVERED The C5 complement pathway has been proposed as a new target for the treatment of asthma, supported by clinical observations of increased C5a levels in asthmatic airways, constitutive expression of C5 receptors on bronchial epithelium and smooth muscle cells, and preclinical studies in mice demonstrating inhibition of C5 cleavage reduced established airway inflammation and improves lung function. Eculizumab is a monoclonal antibody, which binds to the complement protein C5, thereby preventing the formation of C5a and C5b-9. The research discussed in this review describes development of eculizumab for the treatment of paroxysmal nocturnal hemoglobinuria and the efficacy of eculizumab on allergen-induced asthmatic responses in a placebo-controlled study. EXPERT OPINION In an allergen-challenge model of asthma, there was a significant period effect with eculizumab, with inhibition of the late asthmatic response in subjects who received placebo treatment first. Although this study provides some evidence that eculizumab may be effective to attenuate allergen-induced responses, the role of C5 in asthma remains to be clarified.
Collapse
Affiliation(s)
- Steven G Smith
- McMaster University, Department of Medicine, Ontario, Canada
| | | | | | | |
Collapse
|
229
|
Complement C5a: Impact on the field of veterinary medicine. Vet J 2012; 192:264-71. [DOI: 10.1016/j.tvjl.2011.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 11/30/2011] [Accepted: 12/14/2011] [Indexed: 01/03/2023]
|
230
|
Palmer E, Gray LC, Stott M, Bowen DJ, van den Berg CW. Roles of promoter and 3' untranslated motifs in expression of the human C5a receptor. Mol Immunol 2012; 52:88-95. [PMID: 22608366 DOI: 10.1016/j.molimm.2012.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 04/27/2012] [Accepted: 04/29/2012] [Indexed: 12/26/2022]
Abstract
The C5a receptor (C5aR) is a 7 transmembrane G-protein coupled receptor (GPCR) that mediates the powerful pro-inflammatory effect of the complement activation product C5a. Excess C5a generated under pathological conditions has been implicated in a variety of conditions including sepsis, asthma and rheumatoid arthritis, but very little is known about the regulation of expression of the C5aR. The 5' promoter region and 3' untranslated region (UTR) of the C5aR mRNA were cloned, generating enhanced green fluorescent protein (EGFP)-reporter plasmids, which were transfected into the monocytic cell line U937. Most of the cloned 2kb 5' region was dispensable for the expression of the reporter constructs and the majority of regulatory sequences are in the first 200 bp. Three motifs, a NFκB, a CCAAT and a NFAT site, were identified to be of importance by site directed mutagenesis for basal expression. Analysis of the 3'UTR of the C5aR mRNA showed that it contained two AU-rich elements (AREs), however site directed mutagenesis showed that these had no effect on basal expression. While the phorbol ester PMA and dibutyryl cAMP increased C5aR protein expression, these agents had no effect on the regulation of expression via the promoter or the 3'UTR. This is the first study to investigate the role of both the promoter and 3'UTR in regulating C5aR expression and our results show that regulation of the human C5aR is similar but not identical to that of the mouse C5aR.
Collapse
Affiliation(s)
- Elizabeth Palmer
- Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | | | | | | | | |
Collapse
|
231
|
Dunkelberger J, Zhou L, Miwa T, Song WC. C5aR expression in a novel GFP reporter gene knockin mouse: implications for the mechanism of action of C5aR signaling in T cell immunity. THE JOURNAL OF IMMUNOLOGY 2012; 188:4032-42. [PMID: 22430734 DOI: 10.4049/jimmunol.1103141] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
C5aR is a G protein-coupled receptor for the anaphylatoxin C5a and mediates many proinflammatory reactions. C5aR signaling also has been shown to regulate T cell immunity, but its sites and mechanism of action in this process remain uncertain. In this study, we created a GFP knockin mouse and used GFP as a surrogate marker to examine C5aR expression. GFP was knocked into the 3'-untranslated region of C5ar1 by gene targeting. We show that GFP is expressed highly on Gr-1(+)CD11b(+) cells in the blood, spleen, and bone marrow and moderately on CD11b(+)F4/80(+) circulating leukocytes and elicited peritoneal macrophages. No GFP is detected on resting or activated T lymphocytes or on splenic myeloid or plasmacytoid dendritic cells. In contrast, 5-25% cultured bone marrow-derived dendritic cells expressed GFP. Interestingly, GFP knockin prevented cell surface but not intracellular C5aR expression. We conclude that C5aR is unlikely to play an intrinsic role on murine T cells and primary dendritic cells. Instead, its effect on T cell immunity in vivo may involve CD11b(+)F4/80(+) or other C5aR-expressing leukocytes. Further, our data reveal a surprising role for the 3'-untranslated region of C5aR mRNA in regulating C5aR protein targeting to the plasma membrane.
Collapse
Affiliation(s)
- Jason Dunkelberger
- Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | |
Collapse
|
232
|
Inhibition of inflammation and fibrosis by a complement C5a receptor antagonist in DOCA-salt hypertensive rats. J Cardiovasc Pharmacol 2012; 58:479-86. [PMID: 21753735 DOI: 10.1097/fjc.0b013e31822a7a09] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The anaphylatoxin C5a generated by activation of the innate immunity complement system is a potent inflammatory peptide mediator through the G-protein-coupled receptor C5aR (CD88) present in immune-inflammatory cells, including monocytes, macrophages, neutrophils, T cells, and mast cells. Inflammatory cells infiltrate and initiate the development of fibrosis in the chronically hypertensive heart. In this study, we have investigated whether treatment with a selective C5aR antagonist prevents cardiovascular remodeling in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Control and DOCA-salt rats were treated with PMX53 (AcF-[OPdChaWR], 1 mg·kg·d oral gavage) for 32 days; structural and functional changes in cardiovascular system were determined. DOCA-salt hypertension increased leukocyte extravasation into ventricular tissue, increasing collagen deposition and ventricular stiffness; PMX53 treatment attenuated these changes, thereby improving cardiac function. Further, treatment with PMX53 suppressed an increased expression of C5aR in the left ventricle from DOCA-salt rats, consistent with the reduced infiltration of inflammatory cells. Vascular endothelial dysfunction in thoracic aortic rings was attenuated by PMX53 treatment, but systolic blood pressure was unchanged in DOCA-salt rats. In the heart, PMX53 treatment attenuated inflammatory cell infiltration, fibrosis, and ventricular stiffness, indicating that C5aR is critically involved in ventricular remodeling by regulating inflammatory responses in the hypertensive heart.
Collapse
|
233
|
Heinrich V, Lee CY. Blurred line between chemotactic chase and phagocytic consumption: an immunophysical single-cell perspective. J Cell Sci 2012; 124:3041-51. [PMID: 21914817 DOI: 10.1242/jcs.086413] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
An innate immune cell can sense a pathogen, either from a distance by recognizing chemoattractant stimuli or by direct physical contact. The pathogen is subsequently neutralized, which usually occurs through its phagocytic internalization. By investigating chemotaxis and phagocytosis from an immunophysical single-cell perspective, it now appears that the demarcation between these two processes is less distinct than originally thought. Several lines of evidence support this notion. First, chemotactic stimulation does not cease at the moment of initial contact between the cell and the pathogenic target. Second, even when classical chemotaxis of neutrophils is suppressed, the early cell response to contact with typical chemoattractant targets, such as zymosan, fungal spores or chemokine-coated particles, can still involve morphological attributes of chemotaxis. Recognizing that the changing morphology of motile cells is inextricably linked to physical cell behavior, this Commentary focuses on the mechanical aspects of the early response of innate immune cells to chemotactic and phagocytic stimuli. On the basis of this perspective, we propose that the combined study of chemotaxis and phagocytosis will, potentially, not only advance our grasp of the mechanisms underlying immune-cell motility but also open new lines of research that will promote a deeper understanding of the innate recognition of pathogens.
Collapse
Affiliation(s)
- Volkmar Heinrich
- Department of Biomedical Engineering, University of California, Davis, CA 95616, USA.
| | | |
Collapse
|
234
|
Thundyil J, Pavlovski D, Hsieh YH, Gelderblom M, Magnus T, Fairlie DP, Arumugam TV. C5a receptor (CD88) inhibition improves hypothermia-induced neuroprotection in an in vitro ischemic model. Neuromolecular Med 2012; 14:30-9. [PMID: 22249919 DOI: 10.1007/s12017-012-8167-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 01/06/2012] [Indexed: 12/26/2022]
Abstract
The concept of 'salvageble penumbra' has prompted both scientists and physicians to explore various neuroprotective approaches that could be beneficial during stroke therapy. Unfortunately, most of them have proved ineffective in targeting multiple cellular death cascades incited within the ischemic penumbra. Hypothermia has been shown to be capable of addressing this problem to some extent. Although many studies have shown that hypothermia targets several cellular processes, its effects on innate immune receptor-mediated apoptotic death still remain unclear. Moreover, whether inhibiting the signaling of innate immune receptors like complement anaphylatoxin C5a receptor (CD88) plays a role in this hypothermic neuroprotection still need to be deciphered. Using various types of ischemic insults in different neuronal cells, we confirm that hypothermia does indeed attenuate apoptotic neuronal cell death in vitro and this effect can be further enhanced by pharmacologically blocking or knocking out CD88. Thus, our study raises a promising therapeutic possibility of adding CD88 antagonists along with hypothermia to improve stroke outcomes.
Collapse
Affiliation(s)
- John Thundyil
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | | | | | | | | | | | | |
Collapse
|
235
|
Schuette-Nuetgen K, Strecker JK, Minnerup J, Ringelstein EB, Schilling M. MCP-1/CCR-2-double-deficiency severely impairs the migration of hematogenous inflammatory cells following transient cerebral ischemia in mice. Exp Neurol 2011; 233:849-58. [PMID: 22197827 DOI: 10.1016/j.expneurol.2011.12.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 12/01/2011] [Accepted: 12/07/2011] [Indexed: 01/17/2023]
Abstract
Monocyte chemoattractant protein-1 (MCP-1) and its receptor CCR-2 are known to play a major role in inflammatory responses after cerebral ischemia. Mice deficient in either MCP-1 or CCR-2 have been reported to develop smaller infarct sizes and show decreased numbers of infiltrating inflammatory cells. In the present study we used green fluorescent protein (GFP) transgenic mice to investigate the effect of MCP-1/CCR-2-double deficiency on the recruitment of inflammatory cells in a model of both, mild and severe cerebral ischemia. We show that MCP-1/CCR-2-double deficiency virtually entirely abrogates the recruitment of hematogenous macrophages and significantly reduces neutrophil migration to the ischemic brain 4 and 7 days following focal cerebral ischemia. This argues for a predominant role of the MCP-1/CCR-2 axis in chemotaxis of monocytes despite a wide redundancy in the chemokine-receptor-system. Chemokine analysis revealed that even candidates known to be involved in monocyte and neutrophil recruitment like MIP-1α, CXCL-1, C5a, G-CSF and GM-CSF showed a reduced and delayed or even a lack of relevant compensatory response in MCP-1(-/-)/CCR-2(-/-)-mice. Solely, chemokine receptor 5 (CCR-5) increased early in both, but rose above wildtype levels at day 7 in MCP-1(-/-)/CCR-2(-/-)-animals, which might explain the higher number of activated microglial cells compared to control mice. Our study was, however, not powered to investigate infarct volumes. Further studies are needed to clarify whether these mechanisms of inflammatory cell recruitment might be essential for early infarct development and final infarct size and to evaluate potential therapeutic implications.
Collapse
|
236
|
Inhibitory effects of C4a on chemoattractant and secretagogue functions of the other anaphylatoxins via Gi protein-adenylyl cyclase inhibition pathway in mast cells. Int Immunopharmacol 2011; 12:158-68. [PMID: 22155625 DOI: 10.1016/j.intimp.2011.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 11/10/2011] [Accepted: 11/15/2011] [Indexed: 02/07/2023]
Abstract
A recombinant complement anaphylatoxin, C4a, inhibited chemotaxis, respiratory burst and histamine release in mast cell-like HMC-1 cells that were treated with recombinant C5a anaphylatoxin. C4a also inhibited histamine release from HMC-1 cells that were induced by recombinant C3a. The inhibition of C5a- and C3a-induced leukocyte reactions by C4a was recapitulated in peripheral blood CD133(+) cell-derived differentiated mast cells. In HMC-1 cells, C4a inhibited cytoplasmic Ca(2+) influx, an event that precedes anaphylatoxin-induced chemotactic and secretary responses. A conditioned medium of HMC-1 cells after shortly treated with C4a also inhibited the anaphylatoxin-induced Ca(2+) influx even after removal of C4a, indicating that the effect of C4a is to liberate an autocrine inhibitor from the mast cells. The inhibitor secretion by C4a was prevented with pertussis toxin or with a phosphodiesterase inhibitor. Conversely, an adenylyl cyclase inhibitor reproduced the effect of C4a. C4a decreased the intracellular cyclic AMP concentration of HMC-1 cells, indicating that C4a elicited the Gi protein-adenylyl cyclase inhibition pathway. Neither C4a nor the conditioned medium, however, inhibited Ca(2+) influx and respiratory burst in C5a- or C3a-stimulated peripheral neutrophils, suggesting that these cells lack this inhibitory system. Additionally, in HMC-1 cells, C4a did not inhibit Ca(2+)-independent, Leu72Gln-C5a-stimulated chemotactic response. In agreement with this finding, C4a treatment inhibited ERK1/2 phosphorylation in HMC-1 cells stimulated with other anaphylatoxins but did not inhibit p38MAPK phosphorylation in cells stimulated with Leu72Gln-C5a. Taken together, these findings suggest that the autocrine inhibitory effect elicited by C4a is attributed to interruption of Ca(2+)-dependent intracellular signaling pathway.
Collapse
|
237
|
Neher MD, Weckbach S, Flierl MA, Huber-Lang MS, Stahel PF. Molecular mechanisms of inflammation and tissue injury after major trauma--is complement the "bad guy"? J Biomed Sci 2011; 18:90. [PMID: 22129197 PMCID: PMC3247859 DOI: 10.1186/1423-0127-18-90] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 11/30/2011] [Indexed: 02/07/2023] Open
Abstract
Trauma represents the leading cause of death among young people in industrialized countries. Recent clinical and experimental studies have brought increasing evidence for activation of the innate immune system in contributing to the pathogenesis of trauma-induced sequelae and adverse outcome. As the "first line of defense", the complement system represents a potent effector arm of innate immunity, and has been implicated in mediating the early posttraumatic inflammatory response. Despite its generic beneficial functions, including pathogen elimination and immediate response to danger signals, complement activation may exert detrimental effects after trauma, in terms of mounting an "innocent bystander" attack on host tissue. Posttraumatic ischemia/reperfusion injuries represent the classic entity of complement-mediated tissue damage, adding to the "antigenic load" by exacerbation of local and systemic inflammation and release of toxic mediators. These pathophysiological sequelae have been shown to sustain the systemic inflammatory response syndrome after major trauma, and can ultimately contribute to remote organ injury and death. Numerous experimental models have been designed in recent years with the aim of mimicking the inflammatory reaction after trauma and to allow the testing of new pharmacological approaches, including the emergent concept of site-targeted complement inhibition. The present review provides an overview on the current understanding of the cellular and molecular mechanisms of complement activation after major trauma, with an emphasis of emerging therapeutic concepts which may provide the rationale for a "bench-to-bedside" approach in the design of future pharmacological strategies.
Collapse
Affiliation(s)
- Miriam D Neher
- Department of Orthopaedic Surgery, University of Colorado Denver, School of Medicine, Denver Health Medical Center, 777 Bannock Street, Denver, CO 80204, USA
| | | | | | | | | |
Collapse
|
238
|
Iyer A, Chan V, Brown L. The DOCA-Salt Hypertensive Rat as a Model of Cardiovascular Oxidative and Inflammatory Stress. Curr Cardiol Rev 2011; 6:291-7. [PMID: 22043205 PMCID: PMC3083810 DOI: 10.2174/157340310793566109] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 09/03/2010] [Accepted: 09/15/2010] [Indexed: 02/07/2023] Open
Abstract
Oxidative stress and inflammation are two sides of the same coin that are intricately combined to elicit a chronic pathophysiological stress state, especially as seen in cardiovascular remodelling. In this review, we argue that administration of deoxycorticosterone acetate (DOCA) and sodium chloride to uninephrectomised rats, defined as DOCA-salt hypertensive rats, provides a reliable animal model of oxidative and inflammatory stress in the cardiovascular system. The supporting evidence includes pathophysiological and biochemical changes together with pharmacological responses to synthetic and natural compounds that lower the concentrations of reactive free radical species and that curtail inflammatory responses in the cardiovascular system.
Collapse
Affiliation(s)
- Abishek Iyer
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | | | | |
Collapse
|
239
|
Trujillo G, Zhang J, Habiel DM, Ge L, Ramadass M, Ghebrehiwet B, Kew RR. Cofactor regulation of C5a chemotactic activity in physiological fluids. Requirement for the vitamin D binding protein, thrombospondin-1 and its receptors. Mol Immunol 2011; 49:495-503. [PMID: 22014686 DOI: 10.1016/j.molimm.2011.09.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 09/15/2011] [Accepted: 09/28/2011] [Indexed: 12/15/2022]
Abstract
Factors in physiological fluids that regulate the chemotactic activity of complement activation peptides C5a and C5a des Arg are not well understood. The vitamin D binding protein (DBP) has been shown to significantly enhance chemotaxis to C5a/C5a des Arg. More recently, platelet-derived thrombospondin-1 (TSP-1) has been shown to facilitate the augmentation of C5a-induced chemotaxis by DBP. The objective of this study was to better characterize these chemotactic cofactors and investigate the role that cell surface TSP-1 receptors CD36 and CD47 may play in this process. The chemotactic activity in C-activated normal serum, citrated plasma, DBP-depleted serum or C5 depleted serum was determined for both normal human neutrophils and U937 cell line transfected with the C5a receptor (U937-C5aR). In addition, levels of C5a des Arg, DBP and TSP-1 in these fluids were measured by RIA or ELISA. Results show that there is a clear hierarchy with C5a being the essential primary signal (DBP or TSP-1 will not function in the absence of C5a), DBP the necessary cofactor and TSP-1 a dependent tertiary factor, since it cannot function to enhance chemotaxis to C5a without DBP. Measurement of the C5a-induced intracellular calcium flux confirmed the same hierarchy observed with chemotaxis. Moreover, analysis of bronchoalveolar lavage fluid (BALF) from patients with the adult respiratory distress syndrome (ARDS) demonstrated that C5a-dependent chemotactic activity is significantly decreased after anti-DBP treatment. Finally, results show that TSP-1 utilizes cell surface receptors CD36 and CD47 to augment chemotaxis, but DBP does not bind to TSP-1, CD36 or CD47. The results clearly demonstrate that C5a/C5a des Arg needs both DBP and TSP-1 for maximal chemotactic activity and suggest that the regulation of C5a chemotactic activity in physiological fluids is more complex than previously thought.
Collapse
Affiliation(s)
- Glenda Trujillo
- Department of Pathology, Stony Brook University School of Medicine, Stony Brook, NY 11794-8691, USA
| | | | | | | | | | | | | |
Collapse
|
240
|
Kim SH, Jung DI, Yang IY, Kim J, Lee KY, Nochi T, Kiyono H, Jang YS. M cells expressing the complement C5a receptor are efficient targets for mucosal vaccine delivery. Eur J Immunol 2011; 41:3219-29. [PMID: 21887786 DOI: 10.1002/eji.201141592] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 07/21/2011] [Accepted: 08/26/2011] [Indexed: 11/10/2022]
Abstract
In the mucosal immune system, M cells are known as specialized epithelial cells that take up luminal antigens, although the receptors on M cells and the mechanism of antigen uptake into M cells are not well-understood. Here, we report the expression of the complement C5a receptor (C5aR) on the apical surface of M cells. C5ar mRNA expression in co-cultured Caco-2 human M-like cells was six-fold higher than in mono-cultured cells. C5aR expression was detected together with glycoprotein 2, an M-cell-specific protein, on the apical surface of M-like cells and mouse Peyer's patch M cells. Interestingly, after oral administration of Yersinia enterocolitica which expresses outer membrane protein H (OmpH) that is homologous to the Skp α1 domain of Escherichia coli, a ligand of C5aR, dense clustering and phosphorylation of C5aR were detected in M cells. Finally, targeted antigen delivery to M cells using C5aR as a receptor was achieved using the OmpH α1 of Y. enterocolitica such that the induction of ligand-conjugated antigen-specific immune responses was confirmed in mice after oral immunization of the OmpH β1α1-conjugated antigen. Collectively, we identified C5aR expression on M cells and suggest that C5aR could be used as a target receptor for mucosal antigen delivery.
Collapse
Affiliation(s)
- Sae-Hae Kim
- Department of Molecular Biology and Institute for Molecular Biology and Genetics, Chonbuk National University, Jeonju, Korea
| | | | | | | | | | | | | | | |
Collapse
|
241
|
Balenga NAB, Aflaki E, Kargl J, Platzer W, Schröder R, Blättermann S, Kostenis E, Brown AJ, Heinemann A, Waldhoer M. GPR55 regulates cannabinoid 2 receptor-mediated responses in human neutrophils. Cell Res 2011; 21:1452-69. [PMID: 21467997 PMCID: PMC3132458 DOI: 10.1038/cr.2011.60] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 12/20/2010] [Accepted: 01/12/2011] [Indexed: 12/16/2022] Open
Abstract
The directional migration of neutrophils towards inflammatory mediators, such as chemokines and cannabinoids, occurs via the activation of seven transmembrane G protein coupled receptors (7TM/GPCRs) and is a highly organized process. A crucial role for controlling neutrophil migration has been ascribed to the cannabinoid CB(2) receptor (CB(2)R), but additional modulatory sites distinct from CB(2)R have recently been suggested to impact CB(2)R-mediated effector functions in neutrophils. Here, we provide evidence that the recently de-orphanized 7TM/GPCR GPR55 potently modulates CB(2)R-mediated responses. We show that GPR55 is expressed in human blood neutrophils and its activation augments the migratory response towards the CB(2)R agonist 2-arachidonoylglycerol (2-AG), while inhibiting neutrophil degranulation and reactive oxygen species (ROS) production. Using HEK293 and HL60 cell lines, along with primary neutrophils, we show that GPR55 and CB(2)R interfere with each other's signaling pathways at the level of small GTPases, such as Rac2 and Cdc42. This ultimately leads to cellular polarization and efficient migration as well as abrogation of degranulation and ROS formation in neutrophils. Therefore, GPR55 limits the tissue-injuring inflammatory responses mediated by CB(2)R, while it synergizes with CB(2)R in recruiting neutrophils to sites of inflammation.
Collapse
MESH Headings
- Arachidonic Acids/pharmacology
- Cannabinoid Receptor Modulators/pharmacology
- Cell Degranulation/drug effects
- Cell Degranulation/physiology
- Cell Movement/drug effects
- Cell Movement/physiology
- Endocannabinoids
- Glycerides/pharmacology
- HEK293 Cells
- HL-60 Cells
- Humans
- Inflammation/genetics
- Inflammation/metabolism
- Neutrophil Activation/drug effects
- Neutrophil Activation/physiology
- Neutrophils/metabolism
- Reactive Oxygen Species/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Receptors, Cannabinoid
- Receptors, G-Protein-Coupled/agonists
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- cdc42 GTP-Binding Protein/genetics
- cdc42 GTP-Binding Protein/metabolism
- rac GTP-Binding Proteins/genetics
- rac GTP-Binding Proteins/metabolism
- RAC2 GTP-Binding Protein
Collapse
Affiliation(s)
- Nariman A B Balenga
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, Graz A-8010, Austria
| | - Elma Aflaki
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Julia Kargl
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, Graz A-8010, Austria
| | - Wolfgang Platzer
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, Graz A-8010, Austria
| | - Ralf Schröder
- Section Molecular, Cellular and Pharmacobiology, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Stefanie Blättermann
- Section Molecular, Cellular and Pharmacobiology, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Evi Kostenis
- Section Molecular, Cellular and Pharmacobiology, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Andrew J Brown
- Department of Screening and Compound Profiling, GlaxoSmithKline, Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, UK
| | - Akos Heinemann
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, Graz A-8010, Austria
| | - Maria Waldhoer
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, Graz A-8010, Austria
| |
Collapse
|
242
|
Nishiura H, Zhao R, Yamamoto T. The role of the ribosomal protein S19 C-terminus in altering the chemotaxis of leucocytes by causing functional differences in the C5a receptor response. J Biochem 2011; 150:271-7. [DOI: 10.1093/jb/mvr067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
243
|
Inhibiting the C5-C5a receptor axis. Mol Immunol 2011; 48:1631-42. [PMID: 21549429 DOI: 10.1016/j.molimm.2011.04.014] [Citation(s) in RCA: 227] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 04/12/2011] [Accepted: 04/14/2011] [Indexed: 12/19/2022]
Abstract
Activation of the complement system is a major pathogenic event that drives various inflammatory responses in numerous diseases. All pathways of complement activation lead to cleavage of the C5 molecule generating the anaphylatoxin C5a and, C5b that subsequently forms the terminal complement complex (C5b-9). C5a exerts a predominant pro-inflammatory activity through interactions with the classical G-protein coupled receptor C5aR (CD88) as well as with the non-G protein coupled receptor C5L2 (GPR77), expressed on various immune and non-immune cells. C5b-9 causes cytolysis through the formation of the membrane attack complex (MAC), and sub-lytic MAC and soluble C5b-9 also possess a multitude of non-cytolytic immune functions. These two complement effectors, C5a and C5b-9, generated from C5 cleavage, are key components of the complement system responsible for propagating and/or initiating pathology in different diseases, including paroxysmal nocturnal hemoglobinuria, rheumatoid arthritis, ischemia-reperfusion injuries and neurodegenerative diseases. Thus, the C5-C5a receptor axis represents an attractive target for drug development. This review provides a comprehensive analysis of different methods of inhibiting the generation of C5a and C5b-9 as well as the signalling cascade of C5a via its receptors. These include the inhibition of C5 cleavage through targeting of C5 convertases or via the C5 molecule itself, as well as blocking the activity of C5a by neutralizing antibodies and pharmacological inhibitors, or by targeting C5a receptors per se. Examples of drugs and naturally occurring compounds used are discussed in relation to disease models and clinical trials. To date, only one such compound has thus far made it to clinical medicine: the anti-C5 antibody eculizumab, for treating paroxysmal nocturnal hemoglobinuria. However, a number of drug candidates are rapidly emerging that are currently in early-phase clinical trials. The C5-C5a axis as a target for drug development is highly promising for the treatment of currently intractable major human diseases.
Collapse
|
244
|
Jeong JC, Hwang YH, Kim H, Ro H, Park HC, Kim YJ, Kim MG, Ha J, Park MH, Chae DW, Ahn C, Yang J. Association of complement 5 genetic polymorphism with renal allograft outcomes in Korea. Nephrol Dial Transplant 2011; 26:3378-85. [PMID: 21393613 DOI: 10.1093/ndt/gfr025] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Complements play important roles in both rejection and ischemia-reperfusion injury after transplantation. Complement 5 (C5) is a pivotal complement, which initiates the assembly of the membrane attack complex, and mediates chemotaxis of various immune cells. We investigated the impacts of genetic variations in C5 and its receptor (C5aR) of both recipients and donors on renal allograft outcomes. METHODS Seven single-nucleotide polymorphisms (SNPs) in C5 (rs12237774, rs2159776, rs17611, rs25681, rs2241004, rs10985126 and rs10818500) and one SNP (rs10404456) in the C5aR gene were genotyped in 191 recipient-donor pairs. The association of the polymorphisms with allograft outcomes was determined. RESULTS Three C5 SNPs (rs2159776, rs17611 and rs25681) in recipients had a tendency toward a reduced glomerular filtration rate at 1 year after transplantation. There were four haplotypes in the H2 linkage disequilibrium block, which was formed by four SNPs (rs2159776, rs17611, rs25681 and rs2241004). The GGCG haplotype in both recipients and donors was associated with lower glomerular filtration rate at 1 year (60.9 ± 15.9 versus 66.4 ± 15.5 mL/min/1.73 m(2), P = 0.020; 60.6 ± 15.3 versus 66.2 ± 15.8 mL/min/1.73 m(2), P = 0.017). The association was sustained over 7 years after transplantation (P = 0.015 in recipients; P = 0.039 in donors). The presence of the GGCG haplotype in recipients was associated with poorer graft survival (logrank test, P = 0.024). However, C5 polymorphisms were not correlated with serum C5 level. C5aR polymorphism had no significant impact on the allograft outcomes. CONCLUSIONS The GGCG haplotype of C5 in both recipients and donors was associated with lower renal allograft function.
Collapse
Affiliation(s)
- Jong Cheol Jeong
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
245
|
Heimbach L, Li Z, Berkowitz P, Zhao M, Li N, Rubenstein DS, Diaz LA, Liu Z. The C5a receptor on mast cells is critical for the autoimmune skin-blistering disease bullous pemphigoid. J Biol Chem 2011; 286:15003-9. [PMID: 21393236 DOI: 10.1074/jbc.m111.221036] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bullous pemphigoid (BP) is an autoimmune skin-blistering disease characterized by the presence of autoantibodies against the hemidesmosomal proteins BP230 and BP180. In the IgG passive transfer mouse model of BP, subepidermal blistering is triggered by anti-BP180 antibodies and depends on the complement system, mast cell (MC) degranulation, and neutrophil infiltration. In this study, we have identified the signaling events that connect the activation of the complement system and MC degranulation. We found that mice deficient in MCs or the C5a receptor (C5aR) injected with pathogenic anti-BP180 IgG failed to develop subepidermal blisters and exhibited a drastic reduction in p38 MAPK phosphorylation compared with WT mice. Local reconstitution with MCs from WT but not C5aR-deficient mice restored high levels of p38 MAPK phosphorylation and subepidermal blistering in MC-deficient mice. Local injection of recombinant C5a induced phosphorylation of p38 MAPK in WT but not MC-deficient mice. Cultured mouse MCs treated with recombinant C5a exhibited a significant increase in p38 MAPK phosphorylation and MC degranulation. Taken together, these data demonstrate that C5a interacts with C5aR on MCs and that this C5a-C5aR interaction triggers activation of the p38 MAPK pathway, subsequent MC degranulation, and ultimately BP blistering.
Collapse
Affiliation(s)
- Lisa Heimbach
- Department of Dermatology, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | | | | | | | | | | | | | | |
Collapse
|
246
|
Törő K, Borka K, Kardos M, Kristóf I, Sótonyi P. Expression and Function of C5a Receptor in a Fatal Anaphylaxis After Honey Bee Sting*. J Forensic Sci 2011; 56:526-8. [DOI: 10.1111/j.1556-4029.2010.01681.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
247
|
Jennette JC, Xiao H, Falk R, Gasim AMH. Experimental models of vasculitis and glomerulonephritis induced by antineutrophil cytoplasmic autoantibodies. CONTRIBUTIONS TO NEPHROLOGY 2011; 169:211-220. [PMID: 21252521 DOI: 10.1159/000314776] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Antineutrophil cytoplasmic autoantibodies (ANCA) are closely associated with systemic small vessel vasculitis characterized by segmental vessel wall necrotizing inflammation and a paucity of immunoglobulin deposition. Clinically, in vitro and experimental animal model observations indicate a direct pathogenic role for ANCA. This review focuses on the results of experiments utilizing a mouse model of ANCA disease induced by transfer of mouse anti-MPO IgG or anti-MPO lymphocytes into recipient mice, which causes small vessel vasculitis and glomerulonephritis that closely mimics human disease. Evidence for the following conclusion about this model, and by implication about human ANCA disease, will be summarized as follows: (1) anti-MPO IgG is sufficient even in the absence of functional T cells to cause disease and anti-MPO T lymphocytes are not sufficient to cause acute injury; (2) neutrophils are required; (3) ANCA antigens in bone marrow-derived cells are sufficient targets; (4) increased circulating pro-inflammatory cytokines and microbial products exacerbate disease, and concurrent viral infection exacerbates and modulates the phenotype of disease; (5) Fcγ receptor engagement is required for disease induction, and Fcγ receptor repertoire modulates the phenotype of disease, especially pulmonary disease; (6) activation of the alternative pathway of complement is required, complement is activated by factors released by neutrophils stimulated by ANCA IgG and engagement of C5a receptors is a primary event in complement-mediated amplification; and (7) genetic background has a marked influence on the severity and outcome of disease, and modified gene expression in bone marrow-derived cells is the primary basis for genetically determined differences in disease susceptibility. Investigations using this animal model of ANCA disease have provided important insights into the cellular, molecular and genetic factors involved in the pathogenesis of ANCA disease which are likely to lead to the identification of improved markers of disease activity and response to therapy, as well as more effective and less toxic therapies.
Collapse
|
248
|
Liang S, Krauss JL, Domon H, McIntosh ML, Hosur KB, Qu H, Li F, Tzekou A, Lambris JD, Hajishengallis G. The C5a receptor impairs IL-12-dependent clearance of Porphyromonas gingivalis and is required for induction of periodontal bone loss. THE JOURNAL OF IMMUNOLOGY 2010; 186:869-77. [PMID: 21149611 DOI: 10.4049/jimmunol.1003252] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The C5a anaphylatoxin receptor (C5aR; CD88) is activated as part of the complement cascade and exerts important inflammatory, antimicrobial, and regulatory functions, at least in part, via crosstalk with TLRs. However, the periodontal pathogen Porphyromonas gingivalis can control C5aR activation by generating C5a through its own C5 convertase-like enzymatic activity. In this paper, we show that P. gingivalis uses this mechanism to proactively and selectively inhibit TLR2-induced IL-12p70, whereas the same pathogen-instigated C5aR-TLR2 crosstalk upregulates other inflammatory and bone-resorptive cytokines (IL-1β, IL-6, and TNF-α). In vivo, the ability of P. gingivalis to manipulate TLR2 activation via the C5a-C5aR axis allowed it to escape IL-12p70-dependent immune clearance and to cause inflammatory bone loss in a murine model of experimental periodontitis. In the latter regard, C5aR-deficient or TLR2-deficient mice were both resistant to periodontal bone loss, in stark contrast with wild-type control mice, which is consistent with the interdependent interactions of C5aR and TLR2 in P. gingivalis immune evasion and induction of bone-resorptive cytokines. In conclusion, P. gingivalis targets C5aR to promote its adaptive fitness and cause periodontal disease. Given the current availability of safe and effective C5aR antagonists, pharmacological blockade of C5aR could act therapeutically in human periodontitis and reduce associated systemic risks.
Collapse
Affiliation(s)
- Shuang Liang
- Center for Oral Health and Systemic Disease, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
249
|
Nishiura H, Chen J, Ota Y, Semba U, Higuchi H, Nakashima T, Yamamoto T. Base of molecular mimicry between human ribosomal protein S19 dimer and human C5a anaphylatoxin. Int Immunopharmacol 2010; 10:1541-7. [DOI: 10.1016/j.intimp.2010.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/03/2010] [Accepted: 09/03/2010] [Indexed: 01/26/2023]
|
250
|
Nandakumar KS, Jansson A, Xu B, Rydell N, Ahooghalandari P, Hellman L, Blom AM, Holmdahl R. A recombinant vaccine effectively induces c5a-specific neutralizing antibodies and prevents arthritis. PLoS One 2010; 5:e13511. [PMID: 20975959 PMCID: PMC2958150 DOI: 10.1371/journal.pone.0013511] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 09/17/2010] [Indexed: 11/19/2022] Open
Abstract
Objectives To develop and validate a recombinant vaccine to attenuate inflammation in arthritis by sustained neutralization of the anaphylatoxin C5a. Methods We constructed and expressed fusion protein of C5a and maltose binding protein. Efficacy of specific C5a neutralization was tested using the fusion protein as vaccine in three different arthritis mouse models: collagen induced arthritis (CIA), chronic relapsing CIA and collagen antibody induced arthritis (CAIA). Levels of anti-C5a antibodies and anti-collagen type II were measured by ELISA. C5a neutralization assay was done using a rat basophilic leukemia cell-line transfected with the human C5aR. Complement activity was determined using a hemolytic assay and joint morphology was assessed by histology. Results Vaccination of mice with MBP-C5a led to significant reduction of arthritis incidence and severity but not anti-collagen antibody synthesis. Histology of the MBP-C5a and control (MBP or PBS) vaccinated mice paws confirmed the vaccination effect. Sera from the vaccinated mice developed C5a-specific neutralizing antibodies, however C5 activation and formation of the membrane attack complex by C5b were not significantly altered. Conclusions Exploitation of host immune response to generate sustained C5a neutralizing antibodies without significantly compromising C5/C5b activity is a useful strategy for developing an effective vaccine for antibody mediated and C5a dependent inflammatory diseases. Further developing of such a therapeutic vaccine would be more optimal and cost effective to attenuate inflammation without affecting host immunity.
Collapse
Affiliation(s)
- Kutty Selva Nandakumar
- Medical Inflammation Research, Department of Experimental Medicine, Lund University, Lund, Sweden.
| | | | | | | | | | | | | | | |
Collapse
|