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Yamaguchi T, Katano I, Otsuka I, Ito R, Mochizuki M, Goto M, Takahashi T. Generation of Novel Human Red Blood Cell-Bearing Humanized Mouse Models Based on C3-Deficient NOG Mice. Front Immunol 2021; 12:671648. [PMID: 34386001 PMCID: PMC8353390 DOI: 10.3389/fimmu.2021.671648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022] Open
Abstract
Despite recent advances in immunodeficient mouse models bearing human red blood cells (hRBCs), the elimination of circulating hRBCs by residual innate immune systems remains a significant challenge. In this study, we evaluated the role of mouse complement C3 in the elimination of circulating hRBCs by developing a novel NOG substrain harboring a truncated version of the murine C3 gene (NOG-C3ΔMG2-3). Genetic C3 deletion prolonged the survival of transfused hRBCs in the circulation. Chemical depletion and functional impairment of mouse macrophages, using clodronate liposomes (Clo-lip) or gadolinium chloride (GdCl3), respectively, further extended the survival of hRBCs in NOG-C3ΔMG2-3 mice. Low GdCl3 toxicity allowed the establishment of hRBC-bearing mice, in which hRBCs survived for more than 4 weeks with transfusion once a week. In addition, erythropoiesis of human hematopoietic stem cells (hHSCs) was possible in NOG-C3ΔMG2-3/human GM-CSF-IL-3 transgenic mice with Clo-lip treatment. These findings indicate that mouse models harboring hRBCs can be achieved using NOG-C3ΔMG2-3 mice, which could facilitate studies of human diseases associated with RBCs.
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Affiliation(s)
- Takuya Yamaguchi
- Laboratory Animal Research Department, Central Institute for Experimental Animals (CIEA), Kawasaki, Japan
| | - Ikumi Katano
- Laboratory Animal Research Department, Central Institute for Experimental Animals (CIEA), Kawasaki, Japan
| | - Iyo Otsuka
- Laboratory Animal Research Department, Central Institute for Experimental Animals (CIEA), Kawasaki, Japan
| | - Ryoji Ito
- Laboratory Animal Research Department, Central Institute for Experimental Animals (CIEA), Kawasaki, Japan
| | | | - Motohito Goto
- Animal Resource & Technical Research Center, CIEA, Kawasaki, Japan
| | - Takeshi Takahashi
- Laboratory Animal Research Department, Central Institute for Experimental Animals (CIEA), Kawasaki, Japan
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2
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Garred P, Tenner AJ, Mollnes TE. Therapeutic Targeting of the Complement System: From Rare Diseases to Pandemics. Pharmacol Rev 2021; 73:792-827. [PMID: 33687995 PMCID: PMC7956994 DOI: 10.1124/pharmrev.120.000072] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The complement system was discovered at the end of the 19th century as a heat-labile plasma component that "complemented" the antibodies in killing microbes, hence the name "complement." Complement is also part of the innate immune system, protecting the host by recognition of pathogen-associated molecular patterns. However, complement is multifunctional far beyond infectious defense. It contributes to organ development, such as sculpting neuron synapses, promoting tissue regeneration and repair, and rapidly engaging and synergizing with a number of processes, including hemostasis leading to thromboinflammation. Complement is a double-edged sword. Although it usually protects the host, it may cause tissue damage when dysregulated or overactivated, such as in the systemic inflammatory reaction seen in trauma and sepsis and severe coronavirus disease 2019 (COVID-19). Damage-associated molecular patterns generated during ischemia-reperfusion injuries (myocardial infarction, stroke, and transplant dysfunction) and in chronic neurologic and rheumatic disease activate complement, thereby increasing damaging inflammation. Despite the long list of diseases with potential for ameliorating complement modulation, only a few rare diseases are approved for clinical treatment targeting complement. Those currently being efficiently treated include paroxysmal nocturnal hemoglobinuria, atypical hemolytic-uremic syndrome, myasthenia gravis, and neuromyelitis optica spectrum disorders. Rare diseases, unfortunately, preclude robust clinical trials. The increasing evidence for complement as a pathogenetic driver in many more common diseases suggests an opportunity for future complement therapy, which, however, requires robust clinical trials; one ongoing example is COVID-19 disease. The current review aims to discuss complement in disease pathogenesis and discuss future pharmacological strategies to treat these diseases with complement-targeted therapies. SIGNIFICANCE STATEMENT: The complement system is the host's defense friend by protecting it from invading pathogens, promoting tissue repair, and maintaining homeostasis. Complement is a double-edged sword, since when dysregulated or overactivated it becomes the host's enemy, leading to tissue damage, organ failure, and, in worst case, death. A number of acute and chronic diseases are candidates for pharmacological treatment to avoid complement-dependent damage, ranging from the well established treatment for rare diseases to possible future treatment of large patient groups like the pandemic coronavirus disease 2019.
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Affiliation(s)
- Peter Garred
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Copenhagen, Denmark, and Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (P.G.); Departments of Molecular Biology and Biochemistry, Neurobiology and Behavior, and Pathology and Laboratory Medicine, University of California, Irvine, California (A.J.T.); and Research Laboratory, Nordland Hospital, Bodø, Norway, Faculty of Health Sciences, K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway (T.E.M.); Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway (T.E.M.); and Department of Immunology, Oslo University Hospital and University of Oslo, Oslo, Norway (T.E.M.)
| | - Andrea J Tenner
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Copenhagen, Denmark, and Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (P.G.); Departments of Molecular Biology and Biochemistry, Neurobiology and Behavior, and Pathology and Laboratory Medicine, University of California, Irvine, California (A.J.T.); and Research Laboratory, Nordland Hospital, Bodø, Norway, Faculty of Health Sciences, K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway (T.E.M.); Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway (T.E.M.); and Department of Immunology, Oslo University Hospital and University of Oslo, Oslo, Norway (T.E.M.)
| | - Tom E Mollnes
- Laboratory of Molecular Medicine, Department of Clinical Immunology, Rigshospitalet, Copenhagen, Denmark, and Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (P.G.); Departments of Molecular Biology and Biochemistry, Neurobiology and Behavior, and Pathology and Laboratory Medicine, University of California, Irvine, California (A.J.T.); and Research Laboratory, Nordland Hospital, Bodø, Norway, Faculty of Health Sciences, K.G. Jebsen TREC, University of Tromsø, Tromsø, Norway (T.E.M.); Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway (T.E.M.); and Department of Immunology, Oslo University Hospital and University of Oslo, Oslo, Norway (T.E.M.)
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3
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Elvington M, Liszewski MK, Liszewski AR, Kulkarni HS, Hachem RR, Mohanakumar T, Kim AHJ, Atkinson JP. Development and Optimization of an ELISA to Quantitate C3(H 2 O) as a Marker of Human Disease. Front Immunol 2019; 10:703. [PMID: 31019515 PMCID: PMC6458276 DOI: 10.3389/fimmu.2019.00703] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 03/14/2019] [Indexed: 12/31/2022] Open
Abstract
Discovery of a C3(H2O) uptake pathway has led to renewed interest in this alternative pathway triggering form of C3 in human biospecimens. Previously, a quantifiable method to measure C3(H2O), not confounded by other complement activation products, was unavailable. Herein, we describe a sensitive and specific ELISA for C3(H2O). We initially utilized this assay to determine baseline C3(H2O) levels in healthy human fluids and to define optimal sample storage and handling conditions. We detected ~500 ng/ml of C3(H2O) in fresh serum and plasma, a value substantially lower than what was predicted based on previous studies with purified C3 preparations. After a single freeze-thaw cycle, the C3(H2O) concentration increased 3- to 4-fold (~2,000 ng/ml). Subsequent freeze-thaw cycles had a lesser impact on C3(H2O) generation. Further, we found that storage of human sera or plasma samples at 4°C for up to 22 h did not generate additional C3(H2O). To determine the potential use of C3(H2O) as a biomarker, we evaluated specimens from patients with inflammatory-driven diseases. C3(H2O) concentrations were moderately increased (1.5- to 2-fold) at baseline in sera from active systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients compared to healthy controls. In addition, upon challenge with multiple freeze-thaw cycles or incubation at 22 or 37°C, C3(H2O) generation was significantly enhanced in SLE and RA patients' sera. In bronchoalveolar lavage fluid from lung-transplant recipients, we noted a substantial increase in C3(H2O) within 3 months of acute antibody-mediated rejection. In conclusion, we have established an ELISA for assessing C3(H2O) as a diagnostic and prognostic biomarker in human diseases.
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Affiliation(s)
- Michelle Elvington
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - M Kathryn Liszewski
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Alexis R Liszewski
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Hrishikesh S Kulkarni
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - Ramsey R Hachem
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | | | - Alfred H J Kim
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
| | - John P Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, United States
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4
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Devaurs D, Antunes DA, Kavraki LE. Revealing Unknown Protein Structures Using Computational Conformational Sampling Guided by Experimental Hydrogen-Exchange Data. Int J Mol Sci 2018; 19:E3406. [PMID: 30384411 PMCID: PMC6280153 DOI: 10.3390/ijms19113406] [Citation(s) in RCA: 2] [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: 09/24/2018] [Revised: 10/19/2018] [Accepted: 10/25/2018] [Indexed: 11/17/2022] Open
Abstract
Both experimental and computational methods are available to gather information about a protein's conformational space and interpret changes in protein structure. However, experimentally observing and computationally modeling large proteins remain critical challenges for structural biology. Our work aims at addressing these challenges by combining computational and experimental techniques relying on each other to overcome their respective limitations. Indeed, despite its advantages, an experimental technique such as hydrogen-exchange monitoring cannot produce structural models because of its low resolution. Additionally, the computational methods that can generate such models suffer from the curse of dimensionality when applied to large proteins. Adopting a common solution to this issue, we have recently proposed a framework in which our computational method for protein conformational sampling is biased by experimental hydrogen-exchange data. In this paper, we present our latest application of this computational framework: generating an atomic-resolution structural model for an unknown protein state. For that, starting from an available protein structure, we explore the conformational space of this protein, using hydrogen-exchange data on this unknown state as a guide. We have successfully used our computational framework to generate models for three proteins of increasing size, the biggest one undergoing large-scale conformational changes.
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Affiliation(s)
- Didier Devaurs
- Department of Computer Science, Rice University, 6100 Main St, Houston, TX 77005, USA.
| | - Dinler A Antunes
- Department of Computer Science, Rice University, 6100 Main St, Houston, TX 77005, USA.
| | - Lydia E Kavraki
- Department of Computer Science, Rice University, 6100 Main St, Houston, TX 77005, USA.
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5
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Reply to Kang and Brooks: Comment on the interpretation of binding of Pra1, the fungal immune evasion protein from Candida albicans to the human C3 and on the conformational changes of C3 upon activation: Kang and Brooks Optimization of biolayer-interferometry-based binding assay of he interaction between the Candida albicans protein Pra1 and complement protein C3. Mol Immunol 2018; 101:638-639. [PMID: 30177355 DOI: 10.1016/j.molimm.2018.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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Devaurs D, Papanastasiou M, Antunes DA, Abella JR, Moll M, Ricklin D, Lambris JD, Kavraki LE. Native State of Complement Protein C3d Analysed via Hydrogen Exchange and Conformational Sampling. INTERNATIONAL JOURNAL OF COMPUTATIONAL BIOLOGY AND DRUG DESIGN 2018; 11:90-113. [PMID: 30700993 PMCID: PMC6349257 DOI: 10.1504/ijcbdd.2018.090834] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen/deuterium exchange detected by mass spectrometry (HDXMS) provides valuable information on protein structure and dynamics. Although HDX-MS data is often interpreted using crystal structures, it was suggested that conformational ensembles produced by molecular dynamics simulations yield more accurate interpretations. In this paper, we analyse the complement protein C3d by performing an HDX-MS experiment, and evaluate several interpretation methodologies using an existing prediction model to derive HDX-MS data from protein structure. To interpret and refine C3d's HDX-MS data, we look for a conformation (or conformational ensemble) of C3d that allows computationally replicating this data. We confirm that crystal structures are not a good choice and suggest that conformational ensembles produced by molecular dynamics simulations might not always be satisfactory either. Finally, we show that coarse-grained conformational sampling of C3d produces a conformation from which its HDX-MS data can be replicated and refined.
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Affiliation(s)
- Didier Devaurs
- Department of Computer Science, Rice University, Houston, TX, USA
| | - Malvina Papanastasiou
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Broad Institute of MIT & Harvard, Cambridge, MA, USA
| | - Dinler A Antunes
- Department of Computer Science, Rice University, Houston, TX, USA
| | - Jayvee R Abella
- Department of Computer Science, Rice University, Houston, TX, USA
| | - Mark Moll
- Department of Computer Science, Rice University, Houston, TX, USA
| | - Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lydia E Kavraki
- Department of Computer Science, Rice University, Houston, TX, USA
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7
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Papanastasiou M, Koutsogiannaki S, Sarigiannis Y, Geisbrecht BV, Ricklin D, Lambris JD. Structural Implications for the Formation and Function of the Complement Effector Protein iC3b. THE JOURNAL OF IMMUNOLOGY 2017; 198:3326-3335. [PMID: 28258193 DOI: 10.4049/jimmunol.1601864] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/10/2017] [Indexed: 01/17/2023]
Abstract
Complement-mediated opsonization, phagocytosis, and immune stimulation are critical processes in host defense and homeostasis, with the complement activation fragment iC3b playing a key effector role. To date, however, there is no high-resolution structure of iC3b, and some aspects of its structure-activity profile remain controversial. Here, we employed hydrogen-deuterium exchange mass spectrometry to describe the structure and dynamics of iC3b at a peptide resolution level in direct comparison with its parent protein C3b. In our hydrogen-deuterium exchange mass spectrometry study, 264 peptides were analyzed for their deuterium content, providing almost complete sequence coverage for this 173-kDa protein. Several peptides in iC3b showed significantly higher deuterium uptake when compared with C3b, revealing more dynamic, solvent-exposed regions. Most of them resided in the CUB domain, which contains the heptadecapeptide C3f that is liberated during the conversion of C3b to iC3b. Our data suggest a highly disordered CUB, which has acquired a state similar to that of intrinsically disordered proteins, resulting in a predominant form of iC3b that features high structural flexibility. The structure was further validated using an anti-iC3b mAb that was shown to target an epitope in the CUB region. The information obtained in this work allows us to elucidate determinants of iC3b specificity and activity and provide functional insights into the protein's recognition pattern with respect to regulators and receptors of the complement system.
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Affiliation(s)
- Malvina Papanastasiou
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Sophia Koutsogiannaki
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Yiannis Sarigiannis
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - Brian V Geisbrecht
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506
| | - Daniel Ricklin
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; and
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8
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Sfyroera G, Ricklin D, Reis ES, Chen H, Wu EL, Kaznessis YN, Ekdahl KN, Nilsson B, Lambris JD. Rare loss-of-function mutation in complement component C3 provides insight into molecular and pathophysiological determinants of complement activity. THE JOURNAL OF IMMUNOLOGY 2015; 194:3305-16. [PMID: 25712219 DOI: 10.4049/jimmunol.1402781] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The plasma protein C3 is a central element in the activation and effector functions of the complement system. A hereditary dysfunction of C3 that prevents complement activation via the alternative pathway (AP) was described previously in a Swedish family, but its genetic cause and molecular consequences have remained elusive. In this study, we provide these missing links by pinpointing the dysfunction to a point mutation in the β-chain of C3 (c.1180T > C; p.Met(373)Thr). In the patient's plasma, AP activity was completely abolished and could only be reconstituted with the addition of normal C3. The M373T mutation was localized to the macroglobulin domain 4 of C3, which contains a binding site for the complement inhibitor compstatin and is considered critical for the interaction of C3 with the AP C3 convertase. Structural analyses suggested that the mutation disturbs the integrity of macroglobulin domain 4 and induces conformational changes that propagate into adjacent regions. Indeed, C3 M373T showed an altered binding pattern for compstatin and surface-bound C3b, and the presence of Thr(373) in either the C3 substrate or convertase-affiliated C3b impaired C3 activation and opsonization. In contrast to known gain-of-function mutations in C3, patients affected by this loss-of-function mutation did not develop familial disease, but rather showed diverse and mostly episodic symptoms. Our study therefore reveals the molecular mechanism of a relevant loss-of-function mutation in C3 and provides insight into the function of the C3 convertase, the differential involvement of C3 activity in clinical conditions, and some potential implications of therapeutic complement inhibition.
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Affiliation(s)
- Georgia Sfyroera
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Edimara S Reis
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Hui Chen
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Emilia L Wu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
| | - Yiannis N Kaznessis
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
| | - Kristina N Ekdahl
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, SE-751 85 Uppsala, Sweden; and Linnæus Center of Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden
| | - Bo Nilsson
- Linnæus Center of Biomaterials Chemistry, Linnæus University, SE-391 82 Kalmar, Sweden
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104;
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9
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Panda S, Zhang J, Yang L, Anand GS, Ding JL. Molecular interaction between natural IgG and ficolin--mechanistic insights on adaptive-innate immune crosstalk. Sci Rep 2014; 4:3675. [PMID: 24419227 PMCID: PMC3891018 DOI: 10.1038/srep03675] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 12/13/2013] [Indexed: 11/09/2022] Open
Abstract
Recently, we found that natural IgG (nIgG; a non-specific immunoglobulin of adaptive immunity) is not quiescent, but plays a crucial role in immediate immune defense by collaborating with ficolin (an innate immune protein). However, how the nIgG and ficolin interplay and what factors control the complex formation during infection is unknown. Here, we found that mild acidosis and hypocalcaemia induced by infection- inflammation condition increased the nIgG:ficolin complex formation. Hydrogen-deuterium exchange mass spectrometry delineated the binding interfaces to the CH2-CH3 region of nIgG Fc and P-subdomain of ficolin FBG domain. Infection condition exposes novel binding sites. Site-directed mutagenesis and surface plasmon resonance analyses of peptides, derived from nIgG and ficolin, defined the interacting residues between the proteins. These results provide mechanistic insights on the interaction between two molecules representing the adaptive and innate immune pathways, prompting potential development of immunomodulatory/prophylactic peptides tunable to prevailing infection conditions.
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Affiliation(s)
- Saswati Panda
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543
| | - Jing Zhang
- NUS graduate School for Integrative Science and Engineering, National University of Singapore, Singapore, 117543
- Current address: FIMS & BJRC, The 1 Affiliated Hospital and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China, 710061
| | - Lifeng Yang
- Computational and Systems Biology, Singapore-MIT Alliance, 4 Engineering Drive 3, Singapore, 117576
- Current address: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637511
| | - Ganesh S. Anand
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543
| | - Jeak L. Ding
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543
- Computational and Systems Biology, Singapore-MIT Alliance, 4 Engineering Drive 3, Singapore, 117576
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10
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Ricklin D. Manipulating the mediator: modulation of the alternative complement pathway C3 convertase in health, disease and therapy. Immunobiology 2013; 217:1057-66. [PMID: 22964231 DOI: 10.1016/j.imbio.2012.07.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 07/17/2012] [Accepted: 07/17/2012] [Indexed: 10/27/2022]
Abstract
The complement network is increasingly recognized as an important triage system that is able to differentiate between healthy host cells, microbial intruders, cellular debris and immune complexes, and tailor its actions accordingly. At the center of this triage mechanism is the alternative pathway C3 convertase (C3bBb), a potent enzymatic protein complex capable of rapidly converting the inert yet abundant component C3 into powerful effector fragments (C3a and C3b), thereby amplifying the initial response on unprotected surfaces and inducing a variety of effector functions. A fascinating molecular mechanism of convertase assembly and intrinsic regulation, as well as the interplay with a panel of cell surface-bound and soluble inhibitors are essential for directing complement attack to intruders and protecting healthy host cells. While efficiently keeping immune surveillance and homeostasis on track, the reliance on an intricate cascade of interaction and conversion steps also renders the C3 convertase vulnerable to derail. On the one hand, tissue damage, accumulation of debris, or polymorphisms in complement genes may unfavorably shift the balance between activation and regulation, thereby contributing to a variety of clinical conditions. On the other hand, pathogens developed powerful evasion strategies to avoid complement attack by targeting the convertase. Finally, we increasingly challenge our bodies with foreign materials such as biomaterial implants or drug delivery vehicles that may induce adverse effects that are at least partially caused by complement activation and amplification via the alternative pathway. The involvement of the C3 convertase in a range of pathological conditions put this complex into the spotlight of complement-targeted drug discovery efforts. Fortunately, the physiological regulation and microbial evasion approaches provide a rich source of inspiration for the development of powerful treatment options. This review provides insight into the current knowledge about the molecular mechanisms that drive C3 convertase activity, reveals common and divergent strategies of convertase inhibition employed by host and pathogens, and how this inhibitory arsenal can be tapped for developing therapeutic options to treat complement-related diseases.
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Affiliation(s)
- Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia 19104, USA.
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11
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Progress and Trends in Complement Therapeutics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 735:1-22. [PMID: 22990692 DOI: 10.1007/978-1-4614-4118-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The past few years have proven to be a highly successful and exciting period for the field of complement-directed drug discovery and development. Driven by promising experiences with the first marketed complement drugs, increased knowledge about the involvement of complement in health and disease, and improvements in structural and analytical techniques as well as animal models of disease, the field has seen a surge in creative approaches to therapeutically intervene at various stages of the cascade. An impressive panel of compounds that show promise in clinical trials is meanwhile being lined up in the pipelines of both small biotechnology and big pharmaceutical companies. Yet with this new focus on complement-targeted therapeutics, important questions concerning target selection, point and length of intervention, safety, and drug delivery emerge. In view of the diversity of the clinical disorders involving abnormal complement activity or regulation, which include both acute and chronic diseases and affect a wide range of organs, diverse yet specifically tailored therapeutic approaches may be needed to shift complement back into balance. This chapter highlights the key changes in the field that shape our current perception of complement-targeted drugs and provides a brief overview of recent strategies and emerging trends. Selected examples of complement-related diseases and inhibitor classes are highlighted to illustrate the diversity and creativity in field.
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12
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Garcia BL, Ramyar KX, Ricklin D, Lambris JD, Geisbrecht BV. Advances in understanding the structure, function, and mechanism of the SCIN and Efb families of Staphylococcal immune evasion proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 946:113-33. [PMID: 21948365 DOI: 10.1007/978-1-4614-0106-3_7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Our understanding of both the nature and diversity of Staphylococcal immune evasion proteins has increased tremendously throughout the last several years. Among this group of molecules, members of the SCIN and Efb families of complement inhibitors have been the subject of particularly intense study. This work has demonstrated that both types of proteins exert their primary function by inhibiting C3 convertases, which lie at the heart of the complement-mediated immune response. Despite this similarity, however, significant differences in structure/function relationships and mechanisms of action exist between these bacterial proteins. Furthermore, divergent secondary effects on host immune responses have also been described for these two protein families. This chapter summarizes recent advances toward understanding the structure, function, and mechanism of the SCIN and Efb families, and suggests potential directions for the field over the coming years.
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Affiliation(s)
- Brandon L Garcia
- School of Biological Sciences, University of Missouri, Kansas City, MO 64110, USA.
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13
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Coales SJ, E SY, Lee JE, Ma A, Morrow JA, Hamuro Y. Expansion of time window for mass spectrometric measurement of amide hydrogen/deuterium exchange reactions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:3585-3592. [PMID: 21108306 DOI: 10.1002/rcm.4814] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Backbone amide hydrogen exchange rates can be used to describe the dynamic properties of a protein. Amide hydrogen exchange rates in a native protein may vary from milliseconds (ms) to several years. Ideally, the rates of all amide hydrogens of the analyte protein can be determined individually. To achieve this goal, monitoring of a wider time window is critical, in addition to high sequence coverage and high sequence resolution. Significant improvements have been made to hydrogen/deuterium exchange mass spectrometry methods in the past decade for better sequence coverage and higher sequence resolution. On the other hand, little effort has been made to expand the experimental time window to accurately determine exchange rates of amide hydrogens. Many fast exchanging amide hydrogens are completely exchanged before completion of a typical short exchange time point (10-30 s) and many slow exchanging amide hydrogens do not start exchanging before a typical long exchanging time point (1-3 h). Here various experimental conditions, as well as a quenched-flow apparatus, are utilized to monitor cytochrome c amide hydrogen exchange behaviors over more than eight orders of magnitude (0.0044-1 000 000 s), when converted into the standard exchange condition (pH 7 and 23°C).
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Affiliation(s)
- Stephen J Coales
- ExSAR Corporation, 11 Deer Park Drive, Suite 103, Monmouth Junction, NJ 08852, USA
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Zhang J, Yang L, Ang Z, Yoong SL, Tran TTT, Anand GS, Tan NS, Ho B, Ding JL. Secreted M-ficolin anchors onto monocyte transmembrane G protein-coupled receptor 43 and cross talks with plasma C-reactive protein to mediate immune signaling and regulate host defense. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2010; 185:6899-910. [PMID: 21037097 DOI: 10.4049/jimmunol.1001225] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Although transmembrane C-type lectins (CLs) are known to initiate immune signaling, the participation and mechanism of action of soluble CLs have remained enigmatic. In this study, we found that M-ficolin, a conserved soluble CL of monocyte origin, overcomes its lack of membrane-anchor domain by docking constitutively onto a monocyte transmembrane receptor, G protein-coupled receptor 43 (GPCR43), to form a pathogen sensor-cum-signal transducer. On encountering microbial invaders, the M-ficolin-GPCR43 complex activates the NF-κB cascade to upregulate IL-8 production. We showed that mild acidosis at the local site of infection induces conformational changes in the M-ficolin molecule, which provokes a strong interaction between the C-reactive protein (CRP) and the M-ficolin-GPCR43 complex. The collaboration among CRP-M-ficolin-GPCR43 under acidosis curtails IL-8 production thus preventing immune overactivation. Therefore, we propose that a soluble CL may become membrane-associated through interaction with a transmembrane protein, whereupon infection collaborates with other plasma protein to transduce the infection signal and regulate host defense. Our finding implies a possible mechanism whereby the host might expand its repertoire of immune recognition-cum-regulation tactics by promiscuous protein networking. Furthermore, our identification of the pH-sensitive interfaces of M-ficolin-CRP provides a powerful template for future design of potential immunomodulators.
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Affiliation(s)
- Jing Zhang
- Department of Biological Sciences, National University of Singapore, Singapore
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Self-association and domain rearrangements between complement C3 and C3u provide insight into the activation mechanism of C3. Biochem J 2010; 431:63-72. [PMID: 20666732 DOI: 10.1042/bj20100759] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Component C3 is the central protein of the complement system. During complement activation, the thioester group in C3 is slowly hydrolysed to form C3u, then the presence of C3u enables the rapid conversion of C3 into functionally active C3b. C3u shows functional similarities to C3b. To clarify this mechanism, the self-association properties and solution structures of C3 and C3u were determined using analytical ultracentrifugation and X-ray scattering. Sedimentation coefficients identified two different dimerization events in both proteins. A fast dimerization was observed in 50 mM NaCl but not in 137 mM NaCl. Low amounts of a slow dimerization was observed for C3u and C3 in both buffers. The X-ray radius of gyration RG values were unchanged for both C3 and C3u in 137 mM NaCl, but depend on concentration in 50 mM NaCl. The C3 crystal structure gave good X-ray fits for C3 in 137 mM NaCl. By randomization of the TED (thioester-containing domain)/CUB (for complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domains in the C3b crystal structure, X-ray fits showed that the TED/CUB domains in C3u are extended and differ from the more compact arrangement of C3b. This TED/CUB conformation is intermediate between those of C3 and C3b. The greater exposure of the TED domain in C3u (which possesses the hydrolysed reactive thioester) accounts for the greater self-association of C3u in low-salt conditions. This conformational variability of the TED/CUB domains would facilitate their interactions with a broad range of antigenic surfaces. The second dimerization of C3 and C3u may correspond to a dimer observed in one of the crystal structures of C3b.
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Allosteric inhibition of complement function by a staphylococcal immune evasion protein. Proc Natl Acad Sci U S A 2010; 107:17621-6. [PMID: 20876141 DOI: 10.1073/pnas.1003750107] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The complement system is a major target of immune evasion by Staphylococcus aureus. Although many evasion proteins have been described, little is known about their molecular mechanisms of action. Here we demonstrate that the extracellular fibrinogen-binding protein (Efb) from S. aureus acts as an allosteric inhibitor by inducing conformational changes in complement fragment C3b that propagate across several domains and influence functional regions far distant from the Efb binding site. Most notably, the inhibitor impaired the interaction of C3b with complement factor B and, consequently, formation of the active C3 convertase. As this enzyme complex is critical for both activation and amplification of the complement response, its allosteric inhibition likely represents a fundamental contribution to the overall immune evasion strategy of S. aureus.
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Liao WL, Dodder NG, Mast N, Pikuleva IA, Turko IV. Steroid and protein ligand binding to cytochrome P450 46A1 as assessed by hydrogen-deuterium exchange and mass spectrometry. Biochemistry 2009; 48:4150-8. [PMID: 19317426 DOI: 10.1021/bi900168m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome P450 46A1 (CYP46A1) is a key enzyme responsible for cholesterol elimination from the brain. This P450 can interact with different steroid substrates and protein redox partners. We utilized hydrogen-deuterium (H-D) exchange mass spectrometry for investigating CYP46A1-ligand interactions. First, we tested the applicability of the H-D exchange methodology and assessed the amide proton exchange in substrate-free and cholesterol-sulfate-bound P450. The results showed good correspondence to the available crystal structures and prompted investigation of the CYP46A1 interactions with the two steroid substrates cholesterol and 24S-hydroxycholesterol and the protein redox partner adrenodoxin (Adx). Compared to substrate-free P450, four peptides in cholesterol-bound CYP46A1 (65-80, 109-116, 151-164, and 351-361) and eight peptides in 24S-hydroxycholesterol-bound enzyme (50-64, 65-80, 109-116, 117-125, 129-143, 151-164, 260-270, and 364-373) showed altered deuterium incorporation. Most of these peptides constitute the enzyme active site, whereas the 351-361 peptide is from the region putatively interacting with the redox partner Adx. This also defines the proximal (presumably water) channel that opens in CYP46A1 upon substrate binding. Reciprocal studies of Adx binding to substrate-free and cholesterol-sulfate-bound CYP46A1 revealed changes in the deuteration of the Adx-binding site 144-150 and 351-361 peptides, active site 225-239 and 301-313 peptides, and in the 265-276 peptide, whose functional role is not yet known. The data obtained provide structural insights into how substrate and redox partner binding are coordinated and linked to the hydration of the enzyme active site.
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Affiliation(s)
- Wei-Li Liao
- Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA
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