1
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Jayaraman A, Walachowski S, Bosmann M. The complement system: A key player in the host response to infections. Eur J Immunol 2024; 54:e2350814. [PMID: 39188171 PMCID: PMC11623386 DOI: 10.1002/eji.202350814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 08/13/2024] [Accepted: 08/14/2024] [Indexed: 08/28/2024]
Abstract
Infections are one of the most significant healthcare and economic burdens across the world as underscored by the recent coronavirus pandemic. Moreover, with the increasing incidence of antimicrobial resistance, there is an urgent need to better understand host-pathogen interactions to design effective treatment strategies. The complement system is a key arsenal of the host defense response to pathogens and bridges both innate and adaptive immunity. However, in the contest between pathogens and host defense mechanisms, the host is not always victorious. Pathogens have evolved several approaches, including co-opting the host complement regulators to evade complement-mediated killing. Furthermore, deficiencies in the complement proteins, both genetic and therapeutic, can lead to an inefficient complement-mediated pathogen eradication, rendering the host more susceptible to certain infections. On the other hand, overwhelming infection can provoke fulminant complement activation with uncontrolled inflammation and potentially fatal tissue and organ damage. This review presents an overview of critical aspects of the complement-pathogen interactions during infection and discusses perspectives on designing therapies to mitigate complement dysfunction and limit tissue injury.
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Affiliation(s)
- Archana Jayaraman
- Department of Medicine, Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Sarah Walachowski
- Department of Medicine, Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Markus Bosmann
- Department of Medicine, Pulmonary Center, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
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2
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Pedersen DV, Lorentzen J, Andersen GR. Structural studies offer a framework for understanding the role of properdin in the alternative pathway and beyond. Immunol Rev 2023; 313:46-59. [PMID: 36097870 PMCID: PMC10087229 DOI: 10.1111/imr.13129] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Structures of alternative pathway proteins have offered a comprehensive structural basis for understanding the molecular mechanisms governing activation and regulation of the amplification pathway of the complement cascade. Although properdin (FP) is required in vivo to sustain a functional alternative pathway, structural studies have been lagging behind due to the extended structure and polydisperse nature of FP. We review recent progress with respect to structure determination of FP and its proconvertase/convertase complexes. These structures identify in detail regions in C3b, factor B and FP involved in their mutual interactions. Structures of FP oligomers obtained by integrative studies have shed light on how FP activity depends on its oligomerization state. The accumulated structural knowledge allows us to rationalize the effect of point mutations causing FP deficiency. The structural basis for FP inhibition by the tick CirpA proteins is reviewed and the potential of alphafold2 predictions for understanding the interaction of FP with other tick proteins and the NKp46 receptor on host immune cells is discussed. The accumulated structural knowledge forms a comprehensive basis for understanding molecular interactions involving FP, pathological conditions arising from low levels of FP, and the molecular strategies used by ticks to suppress the alternative pathway.
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Affiliation(s)
| | - Josefine Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
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3
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Beudeker CR, Vijlbrief DC, van Montfrans J, Rooijakkers SH, van der Flier M. Neonatal sepsis and transient immunodeficiency: Potential for novel immunoglobulin therapies? Front Immunol 2022; 13:1016877. [PMID: 36330515 PMCID: PMC9623314 DOI: 10.3389/fimmu.2022.1016877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/04/2022] [Indexed: 10/30/2023] Open
Abstract
Neonates, especially preterm neonates, have the highest risk of sepsis of all age groups. Transient immaturity of the neonatal immune system is an important risk factor. Neonates suffer from hypogammaglobulinemia as nor IgA nor IgM is transferred over the placenta and IgG is only transferred over the placenta late in gestation. In addition, neutrophil numbers and complement function are also decreased. This mini-review focuses on strategies to improve neonatal host-defense. Both clinical and preclinical studies have attempted to boost neonatal immunity to lower the incidence of sepsis and improve outcome. Recent advances in the development of (monoclonal) antibodies show promising results in preclinical studies but have yet to be tested in clinical trials. Strategies to increase complement activity seem efficient in vitro but potential disadvantages such as hyperinflammation have held back further clinical development. Increase of neutrophil numbers has been tested extensively in clinical trials but failed to show improvement in mortality. Future research should focus on clinical applicability of promising new prevention strategies for neonatal sepsis.
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Affiliation(s)
- Coco R. Beudeker
- Department of Pediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Daniel C. Vijlbrief
- Department of Neonatology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Joris M. van Montfrans
- Department of Pediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Suzan H.M. Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Michiel van der Flier
- Department of Pediatric Infectious Diseases and Immunology, University Medical Center Utrecht, Utrecht, Netherlands
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4
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Ali YM, Lynch NJ, Khatri P, Bamigbola IE, Chan ACY, Yabuki M, Demopulos GA, Heeney JL, Pai S, Baxendale H, Schwaeble WJ. Secondary Complement Deficiency Impairs Anti-Microbial Immunity to Klebsiella pneumoniae and Staphylococcus aureus During Severe Acute COVID-19. Front Immunol 2022; 13:841759. [PMID: 35572551 PMCID: PMC9094484 DOI: 10.3389/fimmu.2022.841759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/21/2022] [Indexed: 01/08/2023] Open
Abstract
A high incidence of secondary Klebsiella pneumoniae and Staphylococcus aureus infection were observed in patients with severe COVID-19. The cause of this predisposition to infection is unclear. Our data demonstrate consumption of complement in acute COVID-19 patients reflected by low levels of C3, C4, and loss of haemolytic activity. Given that the elimination of Gram-negative bacteria depends in part on complement-mediated lysis, we hypothesised that secondary hypocomplementaemia is rendering the antibody-dependent classical pathway activation inactive and compromises serum bactericidal activity (SBA). 217 patients with severe COVID-19 were studied. 142 patients suffered secondary bacterial infections. Klebsiella species were the most common Gram-negative organism, found in 58 patients, while S. aureus was the dominant Gram-positive organism found in 22 patients. Hypocomplementaemia was observed in patients with acute severe COVID-19 but not in convalescent survivors three months after discharge. Sera from patients with acute COVID-19 were unable to opsonise either K. pneumoniae or S. aureus and had impaired complement-mediated killing of Klebsiella. We conclude that hyperactivation of complement during acute COVID-19 leads to secondary hypocomplementaemia and predisposes to opportunistic infections.
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Affiliation(s)
- Youssif M. Ali
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Nicholas J. Lynch
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Priyanka Khatri
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Ifeoluwa E. Bamigbola
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Andrew C. Y. Chan
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | | | | | - Jonathan L. Heeney
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Sumita Pai
- Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
| | - Helen Baxendale
- Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom
| | - Wilhelm J. Schwaeble
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, Cambridge, United Kingdom
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5
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Cortes C, Desler C, Mazzoli A, Chen JY, Ferreira VP. The role of properdin and Factor H in disease. Adv Immunol 2022; 153:1-90. [PMID: 35469595 DOI: 10.1016/bs.ai.2021.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The complement system consists of three pathways (alternative, classical, and lectin) that play a fundamental role in immunity and homeostasis. The multifunctional role of the complement system includes direct lysis of pathogens, tagging pathogens for phagocytosis, promotion of inflammatory responses to control infection, regulation of adaptive cellular immune responses, and removal of apoptotic/dead cells and immune complexes from circulation. A tight regulation of the complement system is essential to avoid unwanted complement-mediated damage to the host. This regulation is ensured by a set of proteins called complement regulatory proteins. Deficiencies or malfunction of these regulatory proteins may lead to pro-thrombotic hematological diseases, renal and ocular diseases, and autoimmune diseases, among others. This review focuses on the importance of two complement regulatory proteins of the alternative pathway, Factor H and properdin, and their role in human diseases with an emphasis on: (a) characterizing the main mechanism of action of Factor H and properdin in regulating the complement system and protecting the host from complement-mediated attack, (b) describing the dysregulation of the alternative pathway as a result of deficiencies, or mutations, in Factor H and properdin, (c) outlining the clinical findings, management and treatment of diseases associated with mutations and deficiencies in Factor H, and (d) defining the unwanted and inadequate functioning of properdin in disease, through a discussion of various experimental research findings utilizing in vitro, mouse and human models.
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Affiliation(s)
- Claudio Cortes
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI, United States.
| | - Caroline Desler
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Amanda Mazzoli
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Jin Y Chen
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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6
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Sultan EY, Rizk DE, Kenawy HI, Hassan R. A small fragment of factor B as a potential inhibitor of complement alternative pathway activity. Immunobiology 2021; 226:152106. [PMID: 34147816 DOI: 10.1016/j.imbio.2021.152106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/06/2021] [Accepted: 06/08/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND The complement system is a key player in innate immunity and a modulator of the adaptive immune system. Among the three pathways of complement, the alternative pathway (AP) accounts for most of the complement activation. Factor B (FB) is a major protease of the AP, making it a promising target to inhibit the AP activity in conditions of uncontrolled complement activation. METHODS Based on the data obtained from sequence analysis and conformational changes associated with FB, we expressed and purified a recombinant FB fragment (FBfr). We tested the inhibitory activity of the protein against the AP by in vitro assays. RESULTS FBfr protein was proven to inhibit the complement AP activity when tested by C3b deposition assay and rabbit erythrocyte hemolytic assay. CONCLUSION Our recombinant FBfr was able to compete with the native human FB, which allowed it to inhibit the AP activity. This novel compound is a good candidate for further characterization and testing to be used in complement diagnostic tests and as a drug lead in the field of complement therapeutics.
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Affiliation(s)
- Enas Yasser Sultan
- Department of Microbiology & Immunology, Faculty of Pharmacy, Mansoura University, Egypt
| | - Dina Eid Rizk
- Department of Microbiology & Immunology, Faculty of Pharmacy, Mansoura University, Egypt
| | - Hany Ibrahim Kenawy
- Department of Microbiology & Immunology, Faculty of Pharmacy, Mansoura University, Egypt.
| | - Ramadan Hassan
- Department of Microbiology & Immunology, Faculty of Pharmacy, Mansoura University, Egypt
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7
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Zewde NT, Hsu RV, Morikis D, Palermo G. Systems Biology Modeling of the Complement System Under Immune Susceptible Pathogens. FRONTIERS IN PHYSICS 2021; 9:603704. [PMID: 35145963 PMCID: PMC8827490 DOI: 10.3389/fphy.2021.603704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The complement system is assembled from a network of proteins that function to bring about the first line of defense of the body against invading pathogens. However, complement deficiencies or invasive pathogens can hijack complement to subsequently increase susceptibility of the body to infections. Moreover, invasive pathogens are increasingly becoming resistant to the currently available therapies. Hence, it is important to gain insights into the highly dynamic interaction between complement and invading microbes in the frontlines of immunity. Here, we developed a mathematical model of the complement system composed of 670 ordinary differential equations with 328 kinetic parameters, which describes all three complement pathways (alternative, classical, and lectin) and includes description of mannose-binding lectin, collectins, ficolins, factor H-related proteins, immunoglobulin M, and pentraxins. Additionally, we incorporate two pathogens: (type 1) complement susceptible pathogen and (type 2) Neisseria meningitidis located in either nasopharynx or bloodstream. In both cases, we generate time profiles of the pathogen surface occupied by complement components and the membrane attack complex (MAC). Our model shows both pathogen types in bloodstream are saturated by complement proteins, whereas MACs occupy <<1.0% of the pathogen surface. Conversely, the MAC production in nasopharynx occupies about 1.5-10% of the total N. meningitidis surface, thus making nasal MAC levels at least about eight orders of magnitude higher. Altogether, we predict complement-imbalance, favoring overactivation, is associated with nasopharynx homeostasis. Conversely, orientating toward complement-balance may cause disruption to the nasopharynx homeostasis. Thus, for sporadic meningococcal disease, our model predicts rising nasal levels of complement regulators as early infection biomarkers.
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Affiliation(s)
- Nehemiah T. Zewde
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
| | - Rohaine V. Hsu
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
| | - Dimitrios Morikis
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
- Correspondence: Giulia Palermo, , Dimitrios Morikis,
| | - Giulia Palermo
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
- Department of Chemistry, University of California, Riverside, Riverside, CA, United States
- Correspondence: Giulia Palermo, , Dimitrios Morikis,
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8
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Cui G, Geng L, Zhu L, Lin Z, Liu X, Miao Z, Jiang J, Feng X, Wei F. CFP is a prognostic biomarker and correlated with immune infiltrates in Gastric Cancer and Lung Cancer. J Cancer 2021; 12:3378-3390. [PMID: 33976747 PMCID: PMC8100816 DOI: 10.7150/jca.50832] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 03/21/2021] [Indexed: 01/06/2023] Open
Abstract
Complement factor properdin (CFP), encodes plasma glycoprotein, is a critical gene that regulates the complement pathway of the innate immune system. However, correlations of CFP in cancers remain unclear. In this study, the expression pattern and prognostic value of CFP in pan-cancer were analyzed via the Oncomine, PrognoScan, GEPIA and Kaplan-Meier plotters. In addition, we used immunohistochemical staining to validate CFP expression in clinical tissue samples. Finally, we evaluated the correlations between CFP and cancer immune infiltrates particularly in stomach adenocarcinoma (STAD) and lung adenocarcinoma (LUAD) by using GEPIA and TIMER databases. The results of database analysis and immunohistochemistry showed that the expression level of CFP in STAD and LUAD was lower than that in normal tissues. Low expression level of CFP was associated with poorer overall survival (OS), first progression (FP), post progression survival (PPS) and was detrimental to the prognosis of STAD and LUAD, specifically in stage 3, stage T3, stage N2 and N3 of STAD (P<0.05). Moreover, expression of CFP had significant positive correlations with the infiltration levels of CD8+ T cells, CD4+ T cells, macrophages, neutrophils and dendritic cells (DCs) in STAD and LUAD. Furthermore, gene markers of infiltrating immune cells exhibited different CFP-related immune infiltration patterns such as tumor-associated-macrophages (TAMs). These results suggest that CFP can serve as a prognostic biomarker for determining prognosis and immune infiltration in STAD and LUAD.
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Affiliation(s)
- Guoliang Cui
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China.,The Second Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210017, Jiangsu, China
| | - Le Geng
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Li Zhu
- The Second Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing 210017, Jiangsu, China
| | - Zhenyan Lin
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Xuan Liu
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Zhengyue Miao
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Jintao Jiang
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Xiaoke Feng
- Department of Traditional Chinese Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu, China.,Institute of Integrated Chinese and Western Medicine, Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Fei Wei
- Department of Physiology, School of medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, Jiangsu, China
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9
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Pedersen DV, Pedersen MN, Mazarakis SM, Wang Y, Lindorff-Larsen K, Arleth L, Andersen GR. Properdin oligomers adopt rigid extended conformations supporting function. eLife 2021; 10:63356. [PMID: 33480354 PMCID: PMC7857727 DOI: 10.7554/elife.63356] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/21/2021] [Indexed: 12/19/2022] Open
Abstract
Properdin stabilizes convertases formed upon activation of the complement cascade within the immune system. The biological activity of properdin depends on the oligomerization state, but whether properdin oligomers are rigid and how their structure links to function remains unknown. We show by combining electron microscopy and solution scattering, that properdin oligomers adopt extended rigid and well-defined conformations which are well approximated by single models of apparent n-fold rotational symmetry with dimensions of 230–360 Å. Properdin monomers are pretzel-shaped molecules with limited flexibility. In solution, properdin dimers are curved molecules, whereas trimers and tetramers are close to being planar molecules. Structural analysis indicates that simultaneous binding through all binding sites to surface-linked convertases is unlikely for properdin trimer and tetramers. We show that multivalency alone is insufficient for full activity in a cell lysis assay. Hence, the observed rigid extended oligomer structure is an integral component of properdin function.
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Affiliation(s)
- Dennis V Pedersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Martin Nors Pedersen
- Structural Biophysics, X-ray and Neutron Science, the Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Sofia Mm Mazarakis
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Yong Wang
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lise Arleth
- Structural Biophysics, X-ray and Neutron Science, the Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
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10
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Cools F, Delputte P, Cos P. The search for novel treatment strategies for Streptococcus pneumoniae infections. FEMS Microbiol Rev 2021; 45:6064299. [PMID: 33399826 PMCID: PMC8371276 DOI: 10.1093/femsre/fuaa072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 01/01/2021] [Indexed: 12/13/2022] Open
Abstract
This review provides an overview of the most important novel treatment strategies against Streptococcus pneumoniae infections published over the past 10 years. The pneumococcus causes the majority of community-acquired bacterial pneumonia cases, and it is one of the prime pathogens in bacterial meningitis. Over the last 10 years, extensive research has been conducted to prevent severe pneumococcal infections, with a major focus on (i) boosting the host immune system and (ii) discovering novel antibacterials. Boosting the immune system can be done in two ways, either by actively modulating host immunity, mostly through administration of selective antibodies, or by interfering with pneumococcal virulence factors, thereby supporting the host immune system to effectively overcome an infection. While several of such experimental therapies are promising, few have evolved to clinical trials. The discovery of novel antibacterials is hampered by the high research and development costs versus the relatively low revenues for the pharmaceutical industry. Nevertheless, novel enzymatic assays and target-based drug design, allow the identification of targets and the development of novel molecules to effectively treat this life-threatening pathogen.
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Affiliation(s)
- F Cools
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - P Delputte
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - P Cos
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
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11
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Zhang J, Song L, Pedersen DV, Li A, Lambris JD, Andersen GR, Mollnes TE, Ma YJ, Garred P. Soluble collectin-12 mediates C3-independent docking of properdin that activates the alternative pathway of complement. eLife 2020; 9:60908. [PMID: 32909942 PMCID: PMC7511233 DOI: 10.7554/elife.60908] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/09/2020] [Indexed: 01/11/2023] Open
Abstract
Properdin stabilizes the alternative C3 convertase (C3bBb), whereas its role as pattern-recognition molecule mediating complement activation is disputed for decades. Previously, we have found that soluble collectin-12 (sCL-12) synergizes complement alternative pathway (AP) activation. However, whether this observation is C3 dependent is unknown. By application of the C3-inhibitor Cp40, we found that properdin in normal human serum bound to Aspergillus fumigatus solely in a C3b-dependent manner. Cp40 also prevented properdin binding when properdin-depleted serum reconstituted with purified properdin was applied, in analogy with the findings achieved by C3-depleted serum. However, when opsonized with sCL-12, properdin bound in a C3-independent manner exclusively via its tetrameric structure and directed in situ C3bBb assembly. In conclusion, a prerequisite for properdin binding and in situ C3bBb assembly was the initial docking of sCL-12. This implies a new important function of properdin in host defense bridging pattern recognition and specific AP activation.
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Affiliation(s)
- Jie Zhang
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacy, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Lihong Song
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Pharmaceutical Science, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China
| | - Dennis V Pedersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Anna Li
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Pharmacy, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Tom Eirik Mollnes
- Department of Immunology, Oslo University Hospital, and University of Oslo, Oslo, Norway.,Research Laboratory, Nordland Hospital, K. G. Jebsen TREC, University of Tromsø, Bodø, Norway.,Center of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ying Jie Ma
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Garred
- The Laboratory of Molecular Medicine, Department of Clinical Immunology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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12
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Bain W, Li H, van der Geest R, Moore SR, Olonisakin TF, Ahn B, Papke E, Moghbeli K, DeSensi R, Rapport S, Saul M, Hulver M, Xiong Z, Mallampalli RK, Ray P, Morris A, Ma L, Doi Y, Zhang Y, Kitsios GD, Kulkarni HS, McVerry BJ, Ferreira VP, Nouraie M, Lee JS. Increased Alternative Complement Pathway Function and Improved Survival during Critical Illness. Am J Respir Crit Care Med 2020; 202:230-240. [PMID: 32374177 PMCID: PMC7365364 DOI: 10.1164/rccm.201910-2083oc] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 05/01/2020] [Indexed: 01/16/2023] Open
Abstract
Rationale: Complement is crucial for host defense but may also drive dysregulated inflammation. There is limited understanding of alternative complement function, which can amplify all complement activity, during critical illness.Objectives: We examined the function and key components of the alternative complement pathway in a series of critically ill patients and in a mouse pneumonia model.Methods: Total classical (CH50) and alternative complement (AH50) function were quantified in serum from 321 prospectively enrolled critically ill patients and compared with clinical outcomes. Alternative pathway (AP) regulatory factors were quantified by ELISA (n = 181) and examined via transcriptomics data from external cohorts. Wild-type, Cfb-/-, and C3-/- mice were infected intratracheally with Klebsiella pneumoniae (KP) and assessed for extrapulmonary dissemination.Measurements and Main Results: AH50 greater than or equal to median, but not CH50 greater than or equal to median, was associated with decreased 30-day mortality (adjusted odds ratio [OR], 0.53 [95% confidence interval (CI), 0.31-0.91]), independent of chronic liver disease. One-year survival was improved in patients with AH50 greater than or equal to median (adjusted hazard ratio = 0.59 [95% CI, 0.41-0.87]). Patients with elevated AH50 had increased levels of AP factors B, H, and properdin, and fewer showed a "hyperinflammatory" subphenotype (OR, 0.30 [95% CI, 0.18-0.49]). Increased expression of proximal AP genes was associated with improved survival in two external cohorts. AH50 greater than or equal to median was associated with fewer bloodstream infections (OR, 0.67 [95% CI, 0.45-0.98). Conversely, depletion of AP factors, or AH50 less than median, impaired in vitro serum control of KP that was restored by adding healthy serum. Cfb-/- mice demonstrated increased extrapulmonary dissemination and serum inflammatory markers after intratracheal KP infection compared with wild type.Conclusions: Elevated AP function is associated with improved survival during critical illness, possibly because of enhanced immune capacity.
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Affiliation(s)
- William Bain
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
- Veterans Health Administration Pittsburgh Health System, Pittsburgh, Pennsylvania
| | - Huihua Li
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Rick van der Geest
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Sara R. Moore
- Department of Medical Microbiology and Immunology, University of Toledo College of Life Sciences, Toledo, Ohio
| | - Tolani F. Olonisakin
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Brian Ahn
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Erin Papke
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Kaveh Moghbeli
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Rebecca DeSensi
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Sarah Rapport
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Melissa Saul
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Mei Hulver
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Zeyu Xiong
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | | | - Prabir Ray
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Alison Morris
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
- Center for Medicine and the Microbiome
| | - Lina Ma
- Division of Pulmonary and Critical Care Medicine, Washington University, St. Louis, Missouri
| | - Yohei Doi
- Division of Infectious Diseases, Department of Medicine, and
| | - Yingze Zhang
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Georgios D. Kitsios
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
- Center for Medicine and the Microbiome
| | - Hrishikesh S. Kulkarni
- Division of Pulmonary and Critical Care Medicine, Washington University, St. Louis, Missouri
| | - Bryan J. McVerry
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
- Center for Medicine and the Microbiome
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Viviana P. Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Life Sciences, Toledo, Ohio
| | - Mehdi Nouraie
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Janet S. Lee
- Acute Lung Injury Center of Excellence, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
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13
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Pedersen DV, Rösner T, Hansen AG, Andersen KR, Thiel S, Andersen GR, Valerius T, Laursen NS. Recruitment of properdin by bi-specific nanobodies activates the alternative pathway of complement. Mol Immunol 2020; 124:200-210. [PMID: 32599335 DOI: 10.1016/j.molimm.2020.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 04/28/2020] [Accepted: 06/01/2020] [Indexed: 02/07/2023]
Abstract
The complement system represents a powerful part of the innate immune system capable of removing pathogens and damaged host cells. Nevertheless, only a subset of therapeutic antibodies are capable of inducing complement dependent cytotoxicity, which has fuelled the search for new strategies to potentiate complement activation. Properdin (FP) functions as a positive complement regulator by stabilizing the alternative pathway C3 convertase. Here, we explore a novel strategy for direct activation of the alternative pathway of complement using bi-specific single domain antibodies (nanobodies) that recruit endogenous FP to a cell surface. As a proof-of-principle, we generated bi-specific nanobodies with specificity toward FP and the validated cancer antigen epidermal growth factor receptor (EGFR) and tested their ability to activate complement onto cancer cell lines expressing EGFR. Treatment led to recruitment of FP, complement activation and significant deposition of C3 fragments on the cells in a manner sensitive to the geometry of FP recruitment. The bi-specific nanobodies induced complement dependent lysis of baby hamster kidney cells expressing human EGFR but were unable to lyse human tumour cells due to the presence of complement regulators. Our results confirm that FP can function as a surface bound focal point for initiation of complement activation independent of prior C3b deposition. However, recruitment of FP by bi-specific nanobodies appears insufficient for overcoming the inhibitory action of the negative complement regulators overexpressed by many human tumour cell lines. Our data provide general information on the efficacy of properdin as an initiator of complement but suggest that properdin recruitment on its own may have limited utility as a platform for potent complement activation on regulated cell surfaces.
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Affiliation(s)
- Dennis V Pedersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Gustav Wieds vej 10 C, 8000 Aarhus C, Denmark
| | - Thies Rösner
- Section for Stem Cell Transplantation and Immunotherapy, Department of Medicine II, Christian-Albrechts-University, Rosalind-Franklin-Straße 12, 24103 Kiel, Germany
| | - Annette G Hansen
- Department of Biomedicine, Aarhus University, Høgh-Guldbergs Gade 10, 8000 Aarhus C, Denmark
| | - Kasper R Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Gustav Wieds vej 10 C, 8000 Aarhus C, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Høgh-Guldbergs Gade 10, 8000 Aarhus C, Denmark
| | - Gregers R Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Gustav Wieds vej 10 C, 8000 Aarhus C, Denmark
| | - Thomas Valerius
- Section for Stem Cell Transplantation and Immunotherapy, Department of Medicine II, Christian-Albrechts-University, Rosalind-Franklin-Straße 12, 24103 Kiel, Germany
| | - Nick S Laursen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Gustav Wieds vej 10 C, 8000 Aarhus C, Denmark.
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14
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Koelman DLH, Brouwer MC, van de Beek D. Targeting the complement system in bacterial meningitis. Brain 2020; 142:3325-3337. [PMID: 31373605 PMCID: PMC6821383 DOI: 10.1093/brain/awz222] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 05/15/2019] [Accepted: 05/24/2019] [Indexed: 12/12/2022] Open
Abstract
Bacterial meningitis is most commonly caused by Streptococcus pneumoniae and Neisseria meningitidis and continues to pose a major public health threat. Morbidity and mortality of meningitis are driven by an uncontrolled host inflammatory response. This comprehensive update evaluates the role of the complement system in upregulating and maintaining the inflammatory response in bacterial meningitis. Genetic variation studies, complement level measurements in blood and CSF, and experimental work have together led to the identification of anaphylatoxin C5a as a promising treatment target in bacterial meningitis. In animals and patients with pneumococcal meningitis, the accumulation of neutrophils in the CSF was mainly driven by C5-derived chemotactic activity and correlated positively with disease severity and outcome. In murine pneumococcal meningitis, adjunctive treatment with C5 antibodies prevented brain damage and death. Several recently developed therapeutics target C5 conversion, C5a, or its receptor C5aR. Caution is warranted because treatment with C5 antibodies such as eculizumab also inhibits the formation of the membrane attack complex, which may result in decreased meningococcal killing and increased meningococcal disease susceptibility. The use of C5a or C5aR antagonists to specifically target the harmful anaphylatoxins-induced effects, therefore, are most promising and present opportunities for a phase 2 clinical trial.
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Affiliation(s)
- Diederik L H Koelman
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, AZ, Amsterdam, The Netherlands
| | - Matthijs C Brouwer
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, AZ, Amsterdam, The Netherlands
| | - Diederik van de Beek
- Amsterdam UMC, University of Amsterdam, Department of Neurology, Amsterdam Neuroscience, Meibergdreef 9, AZ, Amsterdam, The Netherlands
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15
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Abd El-Aziz AM, Elgaml A, Ali YM. Bacteriophage Therapy Increases Complement-Mediated Lysis of Bacteria and Enhances Bacterial Clearance After Acute Lung Infection With Multidrug-Resistant Pseudomonas aeruginosa. J Infect Dis 2020; 219:1439-1447. [PMID: 30476337 DOI: 10.1093/infdis/jiy678] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/20/2018] [Indexed: 01/21/2023] Open
Abstract
Emergence of multidrug-resistant (MDR) bacterial infections is a major problem in clinical medicine. Development of new strategies such as phage therapy may be a novel approach for treatment of life-threatening infections caused by MDR bacteria. A newly isolated phage, MMI-Ps1, with strong lytic activity was used for treatment of acute lung infection with Pseudomonas aeruginosa in a mouse model. Intranasal administration of a single dose of MMI-Ps1 immediately after infection provided a significant level of protection and increased the survival duration. Moreover, treatment of infected mice with phage as late as 12 hours after infection was still protective. Our in vitro results are the first to show the synergistic elimination of serum-resistant Pseudomonas strains by phage and complement. Phage therapy increases the efficacy of complement-mediated lysis of serum-resistant P. aeruginosa strains, indicating the importance of an intact complement system in clearing Pseudomonas infection during phage therapy.
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Affiliation(s)
- Abeer M Abd El-Aziz
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
| | - Abdelaziz Elgaml
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
| | - Youssif M Ali
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
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16
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Immunization with proline rich region of pneumococcal surface protein A has no role in protection against Streptococcus pneumoniae serotype 19F. Microb Pathog 2019; 138:103761. [PMID: 31560974 DOI: 10.1016/j.micpath.2019.103761] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/21/2019] [Accepted: 09/24/2019] [Indexed: 11/20/2022]
Abstract
Pneumococcal surface protein A (PspA) is one of the major virulence factors expressed by almost all pneumococcal serotypes and was suggested to be a promising universal vaccine candidate for all pneumococcal sero-groups. Here, we expressed and purified the proline-rich region (PR) of PspA and tested it as a recombinant vaccine against infection caused by a clinical isolate (SP19) of Streptococcus pneumoniae serotype 19F. Our results showed that BALB/c mice immunized with recombinant proline-rich (rPR) region showed a significant higher antibody titre against rPR region compared to control non-immunized group. However, immunized mice or mice recived polyclonal antibodies against rPR region challenged via the intra-peritoneal route with a lethal dose of SP19 isolate showed no significant difference in survival compared to control non-immunized group. These results suggested that, immunization of BALB/c mice with rPR region of PspA is not protective against infection caused by serotype 19F in a mouse model.
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17
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Ali YM, Sim RB, Schwaeble W, Shaaban MI. Enterococcus faecalis Escapes Complement-Mediated Killing via Recruitment of Complement Factor H. J Infect Dis 2019; 220:1061-1070. [PMID: 31058287 DOI: 10.1093/infdis/jiz226] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 05/01/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Enterococcus faecalis is considered to be the most important species of enterococci responsible for blood stream infections in critically ill patients. In blood, the complement system is activated via the classical pathway (CP), the lectin pathway (LP), or the alternative pathway (AP), and it plays a critical role in opsonophagocytosis of bacteria including E faecalis. METHODS In a mouse model of enterococcus peritonitis, BALB-C mice were challenged with a high dose of E faecalis 12 hours after intraperitoneal administration of anti-Factor H (FH) antibodies or isotype control. Four hours later, control mice developed higher bacterial burden in blood and organs compared with mice treated with anti-FH antibodies. RESULTS We demonstrate that complement recognition molecules C1q, CL-11, and murine ficolin-A bind the enterococcus and drive the CP and the LP in human and mouse. We further describe that E faecalis evades the AP by recruitment of FH on its surface. Our results show a strong C3b deposition on E faecalis via both the CP and the LP but not through the AP. CONCLUSIONS These findings indicate that E faecalis avoids the complement phagocytosis by the AP via sequestering complement FH from the host blood.
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Affiliation(s)
- Youssif M Ali
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, United Kingdom
| | - Robert B Sim
- Department of Pharmacology, Oxford University, United Kingdom
| | - Wilhelm Schwaeble
- Department of Veterinary Medicine, School of Biological Sciences, University of Cambridge, United Kingdom
| | - Mona I Shaaban
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
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18
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Abstract
PURPOSE OF REVIEW Pneumococcal meningitis is the most frequent form of bacterial meningitis in Europe and the United States. Although early antimicrobial and adjuvant therapy with dexamethasone have helped to improve disease outcome in adults, mortality and morbidity rates remain unsatisfactorily high, emphasizing the need for additional treatment options. Promising targets for adjuvant therapy have been identified recently and will be the focus of this review. RECENT FINDINGS Brain disease in pneumococcal meningitis is caused by direct bacterial toxicity and excessive meningeal inflammation. Accordingly, promising targets for adjuvant therapy comprise limiting the release of toxic bacterial products and suppressing inflammation in a way that maximally protects against tissue injury without hampering pathogen eradication by antibiotics. Among the agents tested so far in experimental models, complement inhibitors, matrix-metalloproteinase inhibitors, and nonbacteriolytic antibiotics or a combination of the above have the potential to more efficiently protect the brain either alone (e.g., in children and outside the high-income settings) or in addition to adjuvant dexamethasone. Additionally, new protein-based pneumococcal vaccines are being developed that promise to improve disease prevention, namely by addressing the increasing problem of serotype replacement seen with pneumococcal conjugate vaccines. SUMMARY Pneumococcal meningitis remains a life-threatening disease requiring early antibiotic and targeted anti-inflammatory therapy. New adjuvant therapies showed promising results in animal models but need systematic clinical testing.
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19
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The Pneumococcal Surface Proteins PspA and PspC Sequester Host C4-Binding Protein To Inactivate Complement C4b on the Bacterial Surface. Infect Immun 2018; 87:IAI.00742-18. [PMID: 30323030 DOI: 10.1128/iai.00742-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 12/15/2022] Open
Abstract
Complement is a critical component of antimicrobial immunity. Various complement regulatory proteins prevent host cells from being attacked. Many pathogens have acquired the ability to sequester complement regulators from host plasma to evade complement attack. We describe here how Streptococcus pneumoniae adopts a strategy to prevent the formation of the C3 convertase C4bC2a by the rapid conversion of surface bound C4b and iC4b into C4dg, which remains bound to the bacterial surface but no longer forms a convertase complex. Noncapsular virulence factors on the pneumococcus are thought to facilitate this process by sequestering C4b-binding protein (C4BP) from host plasma. When S. pneumoniae D39 was opsonized with human serum, the larger C4 activation products C4b and iC4b were undetectable, but the bacteria were liberally decorated with C4dg and C4BP. With targeted deletions of either PspA or PspC, C4BP deposition was markedly reduced, and there was a corresponding reduction in C4dg and an increase in the deposition of C4b and iC4b. The effect was greatest when PspA and PspC were both knocked out. Infection experiments in mice indicated that the deletion of PspA and/or PspC resulted in the loss of bacterial pathogenicity. Recombinant PspA and PspC both bound serum C4BP, and both led to increased C4b and reduced C4dg deposition on S. pneumoniae D39. We conclude that PspA and PspC help the pneumococcus to evade complement attack by binding C4BP and so inactivating C4b.
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20
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Leonard A, Lalk M. Infection and metabolism – Streptococcus pneumoniae metabolism facing the host environment. Cytokine 2018; 112:75-86. [DOI: 10.1016/j.cyto.2018.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/15/2018] [Accepted: 07/16/2018] [Indexed: 12/21/2022]
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21
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O'Flynn J, Kotimaa J, Faber-Krol R, Koekkoek K, Klar-Mohamad N, Koudijs A, Schwaeble WJ, Stover C, Daha MR, van Kooten C. Properdin binds independent of complement activation in an in vivo model of anti-glomerular basement membrane disease. Kidney Int 2018; 94:1141-1150. [PMID: 30322716 DOI: 10.1016/j.kint.2018.06.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 05/31/2018] [Accepted: 06/28/2018] [Indexed: 12/31/2022]
Abstract
Properdin is the only known positive regulator of complement activation by stabilizing the alternative pathway convertase through C3 binding, thus prolonging its half-life. Recent in vitro studies suggest that properdin may act as a specific pattern recognition molecule. To better understand the role of properdin in vivo, we used an experimental model of acute anti-glomerular basement membrane disease with wild-type, C3- and properdin knockout mice. The model exhibited severe proteinuria, acute neutrophil infiltration and activation, classical and alternative pathway activation, and progressive glomerular deposition of properdin, C3 and C9. Although the acute renal injury was likely due to acute neutrophil activation, we found properdin deposition in C3-knockout mice that was not associated with IgG. Thus, properdin may deposit in injured tissues in vivo independent of its main ligand C3.
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Affiliation(s)
- Joseph O'Flynn
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Juha Kotimaa
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands; University of Helsinki, Faculty of Medicine, Department of Bacteriology and Immunology, Helsinki, Finland
| | - Ria Faber-Krol
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Karin Koekkoek
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Ngaisah Klar-Mohamad
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Angela Koudijs
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Wilhelm J Schwaeble
- University of Leicester, Department of Infection, Immunity and Inflammation, Leicester, UK
| | - Cordula Stover
- University of Leicester, Department of Infection, Immunity and Inflammation, Leicester, UK
| | - Mohamed R Daha
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands
| | - Cees van Kooten
- Leiden University Medical Center, Department of Nephrology, Leiden, The Netherlands.
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22
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Ali YM, Abd El-Aziz AM, Mabrook M, Shabaan AA, Sim RB, Hassan R. Recombinant chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS) protects against LPS-induced lung injury in mice. Clin Immunol 2018; 197:27-33. [PMID: 30145330 DOI: 10.1016/j.clim.2018.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/10/2018] [Accepted: 08/21/2018] [Indexed: 01/13/2023]
Abstract
Acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) are clinical conditions caused by trauma, lung infection or sepsis. ALI/ARDS is associated with massive recruitment of neutrophils into the lung with release of reactive oxygen species and excessive inflammatory response that damage alveolar tissue. Here we report the successful use of a potent recombinant chemotaxis inhibitory protein (rCHIPS) derived from Staphylococcus aureus in reducing the severity of ALI/ARDS. Treatment with rCHIPS reduces pulmonary inflammation and permeability in mice after intranasal administration of lipopolysaccharide (LPS). rCHIPS treatment significantly reduces lung myeloperoxidase (MPO) activity, pro-inflammatory cytokines, broncho-alveolar lavage (BAL) fluid protein content as well as histopathological changes. In addition, treatment with rCHIPS significantly diminishes neutrophils and leukocytes recruitment into lung tissue after LPS administration and hence protects mice from reactive oxygen species mediated lung injury. Our finding reveals potential therapeutic benefits of using rCHIPS for the treatment of ALI/ARDS.
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Affiliation(s)
- Youssif M Ali
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt.
| | - Abeer M Abd El-Aziz
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
| | - Maha Mabrook
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
| | - Ahmed A Shabaan
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Egypt; Faculty of Pharmacy, Aqaba University of Technology, Jordon
| | - Robert B Sim
- Department of Pharmacology, Oxford University, Oxford, UK
| | - Ramadan Hassan
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Egypt
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23
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Dobó J, Kocsis A, Gál P. Be on Target: Strategies of Targeting Alternative and Lectin Pathway Components in Complement-Mediated Diseases. Front Immunol 2018; 9:1851. [PMID: 30135690 PMCID: PMC6092519 DOI: 10.3389/fimmu.2018.01851] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/26/2018] [Indexed: 12/20/2022] Open
Abstract
The complement system has moved into the focus of drug development efforts in the last decade, since its inappropriate or uncontrolled activation has been recognized in many diseases. Some of them are primarily complement-mediated rare diseases, such as paroxysmal nocturnal hemoglobinuria, C3 glomerulonephritis, and atypical hemolytic uremic syndrome. Complement also plays a role in various multifactorial diseases that affect millions of people worldwide, such as ischemia reperfusion injury (myocardial infarction, stroke), age-related macular degeneration, and several neurodegenerative disorders. In this review, we summarize the potential advantages of targeting various complement proteins with special emphasis on the components of the lectin (LP) and the alternative pathways (AP). The serine proteases (MASP-1/2/3, factor D, factor B), which are responsible for the activation of the cascade, are straightforward targets of inhibition, but the pattern recognition molecules (mannose-binding lectin, other collectins, and ficolins), the regulatory components (factor H, factor I, properdin), and C3 are also subjects of drug development. Recent discoveries about cross-talks between the LP and AP offer new approaches for clinical intervention. Mannan-binding lectin-associated serine proteases (MASPs) are not just responsible for LP activation, but they are also indispensable for efficient AP activation. Activated MASP-3 has recently been shown to be the enzyme that continuously supplies factor D (FD) for the AP by cleaving pro-factor D (pro-FD). In this aspect, MASP-3 emerges as a novel feasible target for the regulation of AP activity. MASP-1 was shown to be required for AP activity on various surfaces, first of all on LPS of Gram-negative bacteria.
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Affiliation(s)
- József Dobó
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Andrea Kocsis
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Péter Gál
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
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25
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Chen JY, Cortes C, Ferreira VP. Properdin: A multifaceted molecule involved in inflammation and diseases. Mol Immunol 2018; 102:58-72. [PMID: 29954621 DOI: 10.1016/j.molimm.2018.05.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/16/2018] [Accepted: 05/23/2018] [Indexed: 01/17/2023]
Abstract
Properdin, the widely known positive regulator of the alternative pathway (AP), has undergone significant investigation over the last decade to define its function in inflammation and disease, including its role in arthritis, asthma, and kidney and cardiovascular diseases. Properdin is a glycoprotein found in plasma that is mainly produced by leukocytes and can positively regulate AP activity by stabilizing C3 and C5 convertases and initiating the AP. Promotion of complement activity by properdin results in changes in the cellular microenvironment that contribute to innate and adaptive immune responses, including pro-inflammatory cytokine production, immune cell infiltration, antigen presenting cell maturation, and tissue damage. The use of properdin-deficient mouse models and neutralizing antibodies has contributed to the understanding of the mechanisms by which properdin contributes to promoting or preventing disease pathology. This review mainly focusses on the multifaceted roles of properdin in inflammation and diseases, and how understanding these roles is contributing to the development of new disease therapies.
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Affiliation(s)
- Jin Y Chen
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
| | - Claudio Cortes
- Department of Biomedical Sciences, University of Oakland University School of Medicine, Rochester, MI, United States.
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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Al-Mozaini MA, Tsolaki AG, Abdul-Aziz M, Abozaid SM, Al-Ahdal MN, Pathan AA, Murugaiah V, Makarov EM, Kaur A, Sim RB, Kishore U, Kouser L. Human Properdin Modulates Macrophage: Mycobacterium bovis BCG Interaction via Thrombospondin Repeats 4 and 5. Front Immunol 2018; 9:533. [PMID: 29867915 PMCID: PMC5951972 DOI: 10.3389/fimmu.2018.00533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 03/01/2018] [Indexed: 02/01/2023] Open
Abstract
Mycobacterium tuberculosis can proficiently enter macrophages and diminish complement activation on its cell surface. Within macrophages, the mycobacterium can suppress macrophage apoptosis and survive within the intracellular environment. Previously, we have shown that complement regulatory proteins such as factor H may interfere with pathogen–macrophage interactions during tuberculosis infection. In this study, we show that Mycobacterium bovis BCG binds properdin, an upregulator of the complement alternative pathway. TSR4+5, a recombinant form of thrombospondin repeats 4 and 5 of human properdin expressed in tandem, which is an inhibitor of the alternative pathway, was also able to bind to M. bovis BCG. Properdin and TSR4+5 were found to inhibit uptake of M. bovis BCG by THP-1 macrophage cells in a dose-dependent manner. Quantitative real-time PCR revealed elevated pro-inflammatory responses (TNF-α, IL-1β, and IL-6) in the presence of properdin or TSR4+5, which gradually decreased over 6 h. Correspondingly, anti-inflammatory responses (IL-10 and TGF-β) showed suppressed levels of expression in the presence of properdin, which gradually increased over 6 h. Multiplex cytokine array analysis also revealed that properdin and TSR4+5 significantly enhanced the pro-inflammatory response (TNF-α, IL-1β, and IL-1α) at 24 h, which declined at 48 h, whereas the anti-inflammatory response (IL-10) was suppressed. Our results suggest that properdin may interfere with mycobacterial entry into macrophages via TSR4 and TSR5, particularly during the initial stages of infection, thus affecting the extracellular survival of the pathogen. This study offers novel insights into the non-complement related functions of properdin during host–pathogen interactions in tuberculosis.
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Affiliation(s)
- Maha Ahmed Al-Mozaini
- College of Health and Life Sciences, Brunel University London, London, United Kingdom.,Department of Infection and Immunity, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Anthony G Tsolaki
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Munirah Abdul-Aziz
- College of Health and Life Sciences, Brunel University London, London, United Kingdom.,Department of Biochemistry, Oxford University, Oxford, United Kingdom
| | - Suhair M Abozaid
- College of Health and Life Sciences, Brunel University London, London, United Kingdom.,Department of Infection and Immunity, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Mohammed N Al-Ahdal
- Department of Infection and Immunity, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Ansar A Pathan
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Valarmathy Murugaiah
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Evgeny M Makarov
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Anuvinder Kaur
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Robert B Sim
- Department of Biochemistry, Oxford University, Oxford, United Kingdom
| | - Uday Kishore
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
| | - Lubna Kouser
- College of Health and Life Sciences, Brunel University London, London, United Kingdom
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Wong TCB, Rebbert M, Wang C, Chen X, Heffer A, Zarelli VE, Dawid IB, Zhao H. Genes regulated by potassium channel tetramerization domain containing 15 (Kctd15) in the developing neural crest. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2018; 60:159-66. [PMID: 27389986 DOI: 10.1387/ijdb.160058id] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Neural crest (NC) development is controlled precisely by a regulatory network with multiple signaling pathways and the involvement of many genes. The integration and coordination of these factors are still incompletely understood. Overexpression of Wnt3a and the BMP antagonist Chordin in animal cap cells from Xenopus blastulae induces a large number of NC specific genes. We previously suggested that Potassium Channel Tetramerization Domain containing 15 (Kctd15) regulates NC formation by affecting Wnt signaling and the activity of transcription factor AP-2. In order to advance understanding of the function of Kctd15 during NC development, we performed DNA microarray assays in explants injected with Wnt3a and Chordin, and identified genes that are affected by Kctd15 overexpression. Among the many genes identified, we chose Duf domain containing protein 1 (ddcp1), Platelet-Derived Growth Factor Receptor a (pdgfra), Complement factor properdin (cfp), Zinc Finger SWIM-Type Containing 5 (zswim5), and complement component 3 (C3) to examine their expression by whole mount in situ hybridization. Our work points to a possible role for Kctd15 in the regulation of NC formation and other steps in embryonic development.
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Affiliation(s)
- Thomas C B Wong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, P. R. China
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Blatt AZ, Pathan S, Ferreira VP. Properdin: a tightly regulated critical inflammatory modulator. Immunol Rev 2017; 274:172-190. [PMID: 27782331 PMCID: PMC5096056 DOI: 10.1111/imr.12466] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complement alternative pathway is a powerful arm of the innate immune system that enhances diverse inflammatory responses in the human host. Key to the effects of the alternative pathway is properdin, a serum glycoprotein that can both initiate and positively regulate alternative pathway activity. Properdin is produced by many different leukocyte subsets and circulates as cyclic oligomers of monomeric subunits. While the formation of non‐physiological aggregates in purified properdin preparations and the presence of potential properdin inhibitors in serum have complicated studies of its function, properdin has, regardless, emerged as a key player in various inflammatory disease models. Here, we review basic properdin biology, emphasizing the major hurdles that have complicated the interpretation of results from properdin‐centered studies. In addition, we elaborate on an emerging role for properdin in thromboinflammation and discuss the potential utility of properdin inhibitors as long‐term therapeutic options to treat diseases marked by increased formation of platelet/granulocyte aggregates. Finally, we describe the interplay between properdin and the alternative pathway negative regulator, Factor H, and how aiming to understand these interactions can provide scientists with the most effective ways to manipulate alternative pathway activation in complex systems.
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Affiliation(s)
- Adam Z Blatt
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Sabina Pathan
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.
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29
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Zhuang X, Long EO. Complement factor P: promoting the antibacterial activity of natural killer cells. Cell Mol Immunol 2017; 14:797-799. [PMID: 28737740 DOI: 10.1038/cmi.2017.60] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 06/06/2017] [Indexed: 12/23/2022] Open
Affiliation(s)
- Xiaoxuan Zhuang
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA
| | - Eric O Long
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA
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30
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Narni-Mancinelli E, Gauthier L, Baratin M, Guia S, Fenis A, Deghmane AE, Rossi B, Fourquet P, Escalière B, Kerdiles YM, Ugolini S, Taha MK, Vivier E. Complement factor P is a ligand for the natural killer cell-activating receptor NKp46. Sci Immunol 2017; 2. [PMID: 28480349 DOI: 10.1126/sciimmunol.aam9628] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Innate lymphoid cells (ILCs) are involved in immune responses to microbes and various stressed cells, such as tumor cells. They include group 1 [such as natural killer (NK) cells and ILC1], group 2, and group 3 ILCs. Besides their capacity to respond to cytokines, ILCs detect their targets through a series of cell surface-activating receptors recognizing microbial and nonmicrobial ligands. The nature of some of these ligands remains unclear, limiting our understanding of ILC biology. We focused on NKp46, which is highly conserved in mammals and expressed by all mature NK cells and subsets of ILC1 and ILC3. We show here that NKp46 binds to a soluble plasma glycoprotein, the complement factor P (CFP; properdin), the only known positive regulator of the alternative complement pathway. Consistent with the selective predisposition of patients lacking CFP to lethal Neisseria meningitidis (Nm) infections, NKp46 and group 1 ILCs bearing this receptor were found to be required for mice to survive Nm infection. Moreover, the beneficial effects of CFP treatment for Nm infection were dependent on NKp46 and group 1 NKp46+ ILCs. Thus, group 1 NKp46+ ILCs interact with the complement pathway, via NKp46, revealing a cross-talk between two partners of innate immunity in the response to an invasive bacterial infection.
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Affiliation(s)
- Emilie Narni-Mancinelli
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | | | - Myriam Baratin
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Sophie Guia
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Aurore Fenis
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Ala-Eddine Deghmane
- Institut Pasteur, Invasive Bacterial Infections Unit and National Reference Center for Meningococci, Paris, France
| | | | - Patrick Fourquet
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Bertrand Escalière
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Yann M Kerdiles
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Sophie Ugolini
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Muhamed-Kheir Taha
- Institut Pasteur, Invasive Bacterial Infections Unit and National Reference Center for Meningococci, Paris, France
| | - Eric Vivier
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France.,Service d'Immunologie, Hôpital de la Timone, Assistance Publique-Hôpitaux de Marseille, Marseille, France
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31
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Properdin binding to complement activating surfaces depends on initial C3b deposition. Proc Natl Acad Sci U S A 2017; 114:E534-E539. [PMID: 28069958 DOI: 10.1073/pnas.1612385114] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Two functions have been assigned to properdin; stabilization of the alternative convertase, C3bBb, is well accepted, whereas the role of properdin as pattern recognition molecule is controversial. The presence of nonphysiological aggregates in purified properdin preparations and experimental models that do not allow discrimination between the initial binding of properdin and binding secondary to C3b deposition is a critical factor contributing to this controversy. In previous work, by inhibiting C3, we showed that properdin binding to zymosan and Escherichia coli is not a primary event, but rather is solely dependent on initial C3 deposition. In the present study, we found that properdin in human serum bound dose-dependently to solid-phase myeloperoxidase. This binding was dependent on C3 activation, as demonstrated by the lack of binding in human serum with the C3-inhibitor compstatin Cp40, in C3-depleted human serum, or when purified properdin is applied in buffer. Similarly, binding of properdin to the surface of human umbilical vein endothelial cells or Neisseria meningitidis after incubation with human serum was completely C3-dependent, as detected by flow cytometry. Properdin, which lacks the structural homology shared by other complement pattern recognition molecules and has its major function in stabilizing the C3bBb convertase, was found to bind both exogenous and endogenous molecular patterns in a completely C3-dependent manner. We therefore challenge the view of properdin as a pattern recognition molecule, and argue that the experimental conditions used to test this hypothesis should be carefully considered, with emphasis on controlling initial C3 activation under physiological conditions.
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32
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Kouser L, Abdul-Aziz M, Tsolaki AG, Singhal D, Schwaeble WJ, Urban BC, Khan HA, Sim RB, Kishore U. A recombinant two-module form of human properdin is an inhibitor of the complement alternative pathway. Mol Immunol 2016; 73:76-87. [PMID: 27060503 DOI: 10.1016/j.molimm.2016.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/04/2016] [Accepted: 03/07/2016] [Indexed: 02/08/2023]
Abstract
Properdin upregulates the alternative complement pathway by binding and stabilising the C3 convertase complex (C3bBb). Properdin is a soluble glycoprotein and its flexible rod-like 53kDa monomers form cyclic polymers (dimers, trimers, tetramers and pentamers). The properdin monomer consists of seven thrombospondin type I repeats (TSR 0-6), which are similar and homologous to domains found in circumsporozoite and thrombospondin-related anonymous proteins of Plasmodium species, ETP100 of Eimeria tenella, various complement components C6-C9, and thrombospondin I and II. Using deletion constructs, TSR4 and TSR5 of human properdin were implicated in C3b binding and stabilising C3 convertase. However, individually expressed TSR4 or TSR5 failed to bind properdin ligands. Here, we have expressed and characterized biologically active TSR4 and TSR5 together (TSR4+5) in tandem in Escherichia coli, fused to maltose-binding protein. MBP-TSR4+5 bind solid-phase C3b, sulfatides and glycosaminoglycans. In addition, functionally active recombinant TSR4+5 modules inhibit the alternative pathway of complement.
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Affiliation(s)
- Lubna Kouser
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Munirah Abdul-Aziz
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK; Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Anthony G Tsolaki
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Dipti Singhal
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Wilhelm J Schwaeble
- Department of Infection, Immunity and Inflammation, Maurice Shock Medical Sciences Building, University Road, Leicester, LE1 9HN, UK
| | - Britta C Urban
- Liverpool School of Tropical Medicine, Pembroke Place Liverpool, L3 5QA, UK
| | - Haseeb A Khan
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Robert B Sim
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK; Department of Infection, Immunity and Inflammation, Maurice Shock Medical Sciences Building, University Road, Leicester, LE1 9HN, UK
| | - Uday Kishore
- Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK.
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33
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Jaillon S, Ponzetta A, Magrini E, Barajon I, Barbagallo M, Garlanda C, Mantovani A. Fluid phase recognition molecules in neutrophil-dependent immune responses. Semin Immunol 2016; 28:109-18. [PMID: 27021644 DOI: 10.1016/j.smim.2016.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 03/09/2016] [Accepted: 03/12/2016] [Indexed: 01/01/2023]
Abstract
The innate immune system comprises both a cellular and a humoral arm. Neutrophils are key effector cells of the immune and inflammatory responses and have emerged as a major source of humoral pattern recognition molecules (PRMs). These molecules, which include collectins, ficolins, and pentraxins, are specialised in the discrimination of self versus non-self and modified-self and share basic multifunctional properties including recognition and opsonisation of pathogens and apoptotic cells, activation and regulation of the complement cascade and tuning of inflammation. Neutrophils act as a reservoir of ready-made soluble PRMs, such as the long pentraxin PTX3, the peptidoglycan recognition protein PGRP-S, properdin and M-ficolin, which are stored in neutrophil granules and are involved in neutrophil effector functions. In addition, other soluble PRMs, such as members of the collectin family, are not expressed in neutrophils but can modulate neutrophil-dependent immune responses. Therefore, soluble PRMs are an essential part of the innate immune response and retain antibody-like effector functions. Here, we will review the expression and general function of soluble PRMs, focusing our attention on molecules involved in neutrophil effector functions.
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Affiliation(s)
- Sébastien Jaillon
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, via Manzoni 56, 20089 Rozzano, Milan, Italy; Department of Biomedical Sciences, Humanitas University, Via Manzoni 113, 20089 Rozzano, Milan, Italy.
| | - Andrea Ponzetta
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Elena Magrini
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Isabella Barajon
- Department of Biomedical Sciences, Humanitas University, Via Manzoni 113, 20089 Rozzano, Milan, Italy
| | - Marialuisa Barbagallo
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Cecilia Garlanda
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, via Manzoni 56, 20089 Rozzano, Milan, Italy; Department of Biomedical Sciences, Humanitas University, Via Manzoni 113, 20089 Rozzano, Milan, Italy
| | - Alberto Mantovani
- Department of Immunology and Inflammation, Humanitas Clinical and Research Center, via Manzoni 56, 20089 Rozzano, Milan, Italy; Department of Biomedical Sciences, Humanitas University, Via Manzoni 113, 20089 Rozzano, Milan, Italy.
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34
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van der Maten E, van Selm S, Langereis JD, Bootsma HJ, van Opzeeland FJH, de Groot R, de Jonge MI, van der Flier M. Alternative Pathway Inhibition by Exogenous Factor H Fails to Attenuate Inflammation and Vascular Leakage in Experimental Pneumococcal Sepsis in Mice. PLoS One 2016; 11:e0149307. [PMID: 26872035 PMCID: PMC4752313 DOI: 10.1371/journal.pone.0149307] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 01/30/2016] [Indexed: 11/18/2022] Open
Abstract
Streptococcus pneumoniae is a common cause of sepsis. Effective complement activation is an important component of host defence against invading pathogens, whilst excessive complement activation has been associated with endothelial dysfunction and organ damage. The alternative pathway amplification loop is important for the enhancement of complement activation. Factor H is a key negative regulator of the alternative pathway amplification loop and contributes to tight control of complement activation. We assessed the effect of inhibition of the alternative pathway on sepsis associated inflammation and disease severity using human factor H treatment in a clinically relevant mice model of pneumococcal sepsis. Mice were infected intravenously with live Streptococcus pneumoniae. At the first clinical signs of infection, 17 hours post-infection, mice were treated with ceftriaxone antibiotic. At the same time purified human factor H or in controls PBS was administered. Treatment with human factor H did not attenuate disease scores, serum pro-inflammatory cytokines, or vascular permeability and did not significantly affect C3 and C3a production at 26 h post-infection. Therefore, we conclude that inhibition of the alternative complement pathway by exogenous human factor H fails to attenuate inflammation and vascular leakage at a clinically relevant intervention time point in pneumococcal sepsis in mice.
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Affiliation(s)
- Erika van der Maten
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
| | - Saskia van Selm
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
| | - Jeroen D. Langereis
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
| | - Hester J. Bootsma
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
| | - Fred J. H. van Opzeeland
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
| | - Ronald de Groot
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
| | - Marien I. de Jonge
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
| | - Michiel van der Flier
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboudumc, Nijmegen, The Netherlands
- Pediatric Infectious Diseases and Immunology, Department of Pediatrics, Radboudumc, Nijmegen, The Netherlands
- * E-mail:
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35
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van der Maten E, Westra D, van Selm S, Langereis JD, Bootsma HJ, van Opzeeland FJH, de Groot R, Ruseva MM, Pickering MC, van den Heuvel LPWJ, van de Kar NCAJ, de Jonge MI, van der Flier M. Complement Factor H Serum Levels Determine Resistance to Pneumococcal Invasive Disease. J Infect Dis 2016; 213:1820-7. [PMID: 26802141 DOI: 10.1093/infdis/jiw029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 01/12/2016] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pneumoniae is a major cause of life-threatening infections. Complement activation plays a vital role in opsonophagocytic killing of pneumococci in blood. Initial complement activation via the classical and lectin pathways is amplified through the alternative pathway amplification loop. Alternative pathway activity is inhibited by complement factor H (FH). Our study demonstrates the functional consequences of the variability in human serum FH levels on host defense. Using an in vivo mouse model combined with human in vitro assays, we show that the level of serum FH correlates with the efficacy of opsonophagocytic killing of pneumococci. In summary, we found that FH levels determine a delicate balance of alternative pathway activity, thus affecting the resistance to invasive pneumococcal disease. Our results suggest that variation in FH expression levels, naturally occurring in the human population, plays a thus far unrecognized role in the resistance to invasive pneumococcal disease.
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Affiliation(s)
| | | | | | | | | | | | | | - Marieta M Ruseva
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
| | - Matthew C Pickering
- Centre for Complement and Inflammation Research, Imperial College, London, United Kingdom
| | | | | | | | - Michiel van der Flier
- Laboratory of Pediatric Infectious Diseases Division of Pediatric Infectious Diseases and Immunology, Department of Pediatrics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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36
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Harder MJ, Anliker M, Höchsmann B, Simmet T, Huber-Lang M, Schrezenmeier H, Ricklin D, Lambris JD, Barlow PN, Schmidt CQ. Comparative Analysis of Novel Complement-Targeted Inhibitors, MiniFH, and the Natural Regulators Factor H and Factor H-like Protein 1 Reveal Functional Determinants of Complement Regulation. THE JOURNAL OF IMMUNOLOGY 2015; 196:866-76. [PMID: 26643478 DOI: 10.4049/jimmunol.1501919] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/04/2015] [Indexed: 01/08/2023]
Abstract
The serum proteins factor H (FH), consisting of 20 complement control protein modules (CCPs), and its splice product FH-like protein 1 (FHL-1; consisting of CCPs 1-7) are major regulators of the alternative pathway (AP) of complement activation. The engineered version of FH, miniFH, contains only the N- and C-terminal portions of FH linked by an optimized peptide and shows ∼ 10-fold higher ex vivo potency. We explored the hypothesis that regulatory potency is enhanced by unmasking of a ligand-binding site in the C-terminal CCPs 19-20 that is cryptic in full-length native FH. Therefore, we produced an FH variant lacking the central domains 10-15 (FHΔ10-15). To explore how avidity affects regulatory strength, we generated a duplicated version of miniFH, termed midiFH. We compared activities of FHΔ10-15 and midiFH to miniFH, FH, and FHL-1. Relative to FH, FHΔ10-15 exhibited an altered binding profile toward C3 activation products and a 5-fold-enhanced complement regulation on a paroxysmal nocturnal hemoglobinuria patient's erythrocytes. Contrary to dogma, FHL-1 and FH exhibited equal regulatory activity, suggesting that the role of FHL-1 in AP regulation has been underestimated. Unexpectedly, a substantially increased avidity for complement opsonins, as seen in midiFH, did not potentiate the inhibitory potential on host cells. In conclusion, comparisons of engineered and native FH-based regulators have identified features that determine high AP regulatory activity on host cells. Unrestricted availability of FH CCPs 19-20 and an optimal spatial orientation between the N- and C-terminal FH regions are key.
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Affiliation(s)
- Markus J Harder
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, 89081 Ulm, Germany
| | - Markus Anliker
- Institute of Transfusion Medicine, University of Ulm, 89081 Ulm, Germany; Institute of Clinical Transfusion Medicine and Immunogenetics, German Red Cross Blood Service Baden-Württemberg - Hessen and University Hospital Ulm, 89081 Ulm, Germany
| | - Britta Höchsmann
- Institute of Transfusion Medicine, University of Ulm, 89081 Ulm, Germany; Institute of Clinical Transfusion Medicine and Immunogenetics, German Red Cross Blood Service Baden-Württemberg - Hessen and University Hospital Ulm, 89081 Ulm, Germany
| | - Thomas Simmet
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, 89081 Ulm, Germany
| | - Markus Huber-Lang
- Department of Traumatology, Center of Surgery, University of Ulm, 89081 Ulm, Germany
| | - Hubert Schrezenmeier
- Institute of Transfusion Medicine, University of Ulm, 89081 Ulm, Germany; Institute of Clinical Transfusion Medicine and Immunogenetics, German Red Cross Blood Service Baden-Württemberg - Hessen and University Hospital Ulm, 89081 Ulm, Germany
| | - Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19102
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19102
| | - Paul N Barlow
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3JJ, United Kingdom; and School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JJ, United Kingdom
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, 89081 Ulm, Germany;
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Abstract
Complement is a key component of immunity with crucial inflammatory and opsonic properties; inappropriate activation of complement triggers or exacerbates inflammatory disease. Complement dysregulation is a core feature of some diseases and contributes to pathology in many others. Approved agents have been developed for and are highly effective in some orphan applications, but their progress to use in more common diseases has been slow. Numerous challenges, such as target concentration or high turnover, limit the efficacy of these agents in humans. Numerous novel agents targeting different parts of the complement system in different ways are now emerging from pre-clinical studies and are entering Phase I/II trials; these agents bring the potential for more-effective and more-specific anti-complement therapies in disease. Other agents, both biologic and small molecule, are in Phase II or III trials for both rare and common diseases — administration routes include localized (for example, intravitreal) and systemic routes. There is an urgent need to develop biomarkers and imaging methods that enable monitoring of the effects and efficacy of anti-complement agents.
The complement cascade, a key regulator of innate immunity, is a rich source of potential therapeutic targets for diseases including autoimmune, inflammatory and degenerative disorders. Morgan and Harris discuss the progress made in modulating the complement system and the existing challenges, including dosing, localization of the drug to the target and how to interfere with protein–protein interactions. The complement system is a key innate immune defence against infection and an important driver of inflammation; however, these very properties can also cause harm. Inappropriate or uncontrolled activation of complement can cause local and/or systemic inflammation, tissue damage and disease. Complement provides numerous options for drug development as it is a proteolytic cascade that involves nine specific proteases, unique multimolecular activation and lytic complexes, an arsenal of natural inhibitors, and numerous receptors that bind to activation fragments. Drug design is facilitated by the increasingly detailed structural understanding of the molecules involved in the complement system. Only two anti-complement drugs are currently on the market, but many more are being developed for diseases that include infectious, inflammatory, degenerative, traumatic and neoplastic disorders. In this Review, we describe the history, current landscape and future directions for anti-complement therapies.
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Activated Complement Factors as Disease Markers for Sepsis. DISEASE MARKERS 2015; 2015:382463. [PMID: 26420913 PMCID: PMC4572436 DOI: 10.1155/2015/382463] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 08/16/2015] [Indexed: 02/06/2023]
Abstract
Sepsis is a leading cause of death in the United States and worldwide. Early recognition and effective management are essential for improved outcome. However, early recognition is impeded by lack of clinically utilized biomarkers. Complement factors play important roles in the mechanisms leading to sepsis and can potentially serve as early markers of sepsis and of sepsis severity and outcome. This review provides a synopsis of recent animal and clinical studies of the role of complement factors in sepsis development, together with their potential as disease markers. In addition, new results from our laboratory are presented regarding the involvement of the complement factor, mannose-binding lectin, in septic shock patients. Future clinical studies are needed to obtain the complete profiles of complement factors/their activated products during the course of sepsis development. We anticipate that the results of these studies will lead to a multipanel set of sepsis biomarkers which, along with currently used laboratory tests, will facilitate earlier diagnosis, timely treatment, and improved outcome.
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Jain U, Cao Q, Thomas NA, Woodruff TM, Schwaeble WJ, Stover CM, Stadnyk AW. Properdin provides protection from Citrobacter rodentium-induced intestinal inflammation in a C5a/IL-6-dependent manner. THE JOURNAL OF IMMUNOLOGY 2015; 194:3414-21. [PMID: 25725105 DOI: 10.4049/jimmunol.1401814] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Citrobacter rodentium is an attaching and effacing mouse pathogen that models enteropathogenic and enterohemorrhagic Escherichia coli in humans. The complement system is an important innate defense mechanism; however, only scant information is available about the role of complement proteins during enteric infections. In this study, we examined the impact of the lack of properdin, a positive regulator of complement, in C. rodentium-induced colitis. Following infection, properdin knockout (P(KO)) mice had increased diarrhea and exacerbated inflammation combined with defective epithelial cell-derived IL-6 and greater numbers of colonizing bacteria. The defect in the mucosal response was reversed by administering exogenous properdin to P(KO) mice. Then, using in vitro and in vivo approaches, we show that the mechanism behind the exacerbated inflammation of P(KO) mice is due to a failure to increase local C5a levels. We show that C5a directly stimulates IL-6 production from colonic epithelial cells and that inhibiting C5a in infected wild-type mice resulted in defective epithelial IL-6 production and exacerbated inflammation. These outcomes position properdin early in the response to an infectious challenge in the colon, leading to complement activation and C5a, which in turn provides protection through IL-6 expression by the epithelium. Our results unveil a previously unappreciated mechanism of intestinal homeostasis involving complement, C5a, and IL-6 during bacteria-triggered epithelial injury.
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Affiliation(s)
- Umang Jain
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
| | - Qi Cao
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
| | - Nikhil A Thomas
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada; Department of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
| | - Trent M Woodruff
- School of Biomedical Sciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Wilhelm J Schwaeble
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, United Kingdom; and
| | - Cordula M Stover
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, United Kingdom; and
| | - Andrew W Stadnyk
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada; Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada
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Zimmer J, Hobkirk J, Mohamed F, Browning MJ, Stover CM. On the Functional Overlap between Complement and Anti-Microbial Peptides. Front Immunol 2015; 5:689. [PMID: 25646095 PMCID: PMC4298222 DOI: 10.3389/fimmu.2014.00689] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 12/22/2014] [Indexed: 12/19/2022] Open
Abstract
Intriguingly, activated complement and anti-microbial peptides share certain functionalities; lytic, phagocytic, and chemo-attractant activities and each may, in addition, exert cell instructive roles. Each has been shown to have distinct LPS detoxifying activity and may play a role in the development of endotoxin tolerance. In search of the origin of complement, a functional homolog of complement C3 involved in opsonization has been identified in horseshoe crabs. Horseshoe crabs possess anti-microbial peptides able to bind to acyl chains or phosphate groups/saccharides of endotoxin, LPS. Complement activity as a whole is detectable in marine invertebrates. These are also a source of anti-microbial peptides with potential pharmaceutical applicability. Investigating the locality for the production of complement pathway proteins and their role in modulating cellular immune responses are emerging fields. The significance of local synthesis of complement components is becoming clearer from in vivo studies of parenchymatous disease involving specifically generated, complement-deficient mouse lines. Complement C3 is a central component of complement activation. Its provision by cells of the myeloid lineage varies. Their effector functions in turn are increased in the presence of anti-microbial peptides. This may point to a potentiating range of activities, which should serve the maintenance of health but may also cause disease. Because of the therapeutic implications, this review will consider closely studies dealing with complement activation and anti-microbial peptide activity in acute inflammation (e.g., dialysis-related peritonitis, appendicitis, and ischemia).
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Affiliation(s)
- Jana Zimmer
- Department of Infectious Diseases - Medical Microbiology and Hygiene, Ruprecht-Karls-University of Heidelberg , Heidelberg , Germany
| | - James Hobkirk
- Department of Academic Endocrinology, Diabetes and Metabolism, Hull York Medical School, University of Hull , Hull , UK
| | - Fatima Mohamed
- Department of Infection, Immunity and Inflammation, University of Leicester , Leicester , UK
| | - Michael J Browning
- Department of Infection, Immunity and Inflammation, University of Leicester , Leicester , UK ; Department of Immunology, Leicester Royal Infirmary , Leicester , UK
| | - Cordula M Stover
- Department of Infection, Immunity and Inflammation, University of Leicester , Leicester , UK
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Baquero F, Lanza VF, Cantón R, Coque TM. Public health evolutionary biology of antimicrobial resistance: priorities for intervention. Evol Appl 2014; 8:223-39. [PMID: 25861381 PMCID: PMC4380917 DOI: 10.1111/eva.12235] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 10/12/2014] [Indexed: 12/19/2022] Open
Abstract
The three main processes shaping the evolutionary ecology of antibiotic resistance (AbR) involve the emergence, invasion and occupation by antibiotic-resistant genes of significant environments for human health. The process of emergence in complex bacterial populations is a high-frequency, continuous swarming of ephemeral combinatory genetic and epigenetic explorations inside cells and among cells, populations and communities, expanding in different environments (migration), creating the stochastic variation required for evolutionary progress. Invasion refers to the process by which AbR significantly increases in frequency in a given (invaded) environment, led by external invaders local multiplication and spread, or by endogenous conversion. Conversion occurs because of the spread of AbR genes from an exogenous resistant clone into an established (endogenous) bacterial clone(s) colonizing the environment; and/or because of dissemination of particular resistant genetic variants that emerged within an endogenous clonal population. Occupation of a given environment by a resistant variant means a permanent establishment of this organism in this environment, even in the absence of antibiotic selection. Specific interventions on emergence influence invasion, those acting on invasion also influence occupation and interventions on occupation determine emergence. Such interventions should be simultaneously applied, as they are not simple solutions to the complex problem of AbR.
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Affiliation(s)
- Fernando Baquero
- Departamento de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) Madrid, Spain ; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain ; CIBER Epidemiología y Salud Pública (CIBERESP) Madrid, Spain
| | - Val F Lanza
- Departamento de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) Madrid, Spain ; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain ; CIBER Epidemiología y Salud Pública (CIBERESP) Madrid, Spain
| | - Rafael Cantón
- Departamento de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) Madrid, Spain ; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain ; Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III Madrid, Spain
| | - Teresa M Coque
- Departamento de Microbiología, Hospital Universitario Ramón y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) Madrid, Spain ; Unidad de Resistencia a Antibióticos y Virulencia Bacteriana asociada al Consejo Superior de Investigaciones Científicas (CSIC) Madrid, Spain ; CIBER Epidemiología y Salud Pública (CIBERESP) Madrid, Spain
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42
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Complementing antibacterial strategies. Nat Rev Drug Discov 2014. [DOI: 10.1038/nrd4349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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