51
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Tretiakova DS, Khaidukov SV, Babayants AA, Frolova IS, Shcheglovitova ON, Onishchenko NR, Vodovozova EL. Lipophilic Prodrug of Methotrexate in the Membrane of Liposomes Promotes Their Uptake by Human Blood Phagocytes. Acta Naturae 2020; 12:99-109. [PMID: 32477604 PMCID: PMC7245962 DOI: 10.32607/actanaturae.10946] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Previously, we showed that incorporation of methotrexate (MTX) in the form of a lipophilic prodrug (MTXDG) in 100-nm lipid bilayer liposomes of egg phosphatidylcholine can allow one to reduce toxicity and improve the antitumor efficiency of MTX in a mouse model of T-cell leukemic lymphoma. However, in our hemocompatibility tests in vitro, MTX liposomes caused complement (C) activation, obviously due to binding on the liposome surface and fragmentation of the C3 complement factor. In this work, we studied the interactions of MTX liposomes carrying stabilizing molecules phosphatidylinositol (PI), ganglioside GM1, or a lipid conjugate of N-carboxymethylated oligoglycine (CMG) in the bilayer with subpopulations of human blood leukocytes. Liposomes labeled with BODIPY-phosphatidylcholine were incubated with whole blood (30 min and 1 h, 37°C), blood cells were lysed with a hypotonic buffer, and the fluorescence of the liposomes bound but not internalized by the leukocytes was quenched by crystal violet. Cell suspensions were analyzed by flow cytometry. Incorporation of MTXDG dramatically enhanced the phagocytosis of liposomes of any composition by monocytes. Neutrophils consumed much less of the liposomes. Lymphocytes did not accumulate liposomes. The introduction of PI into MTX liposomes practically did not affect the specific consumption of liposomes by monocytes, while CMG was likely to increase the consumption rate regardless of the presence of MTXDG. The GM1 ganglioside presumably shielded MTX liposomes from phagocytosis by one of the monocyte populations and increased the efficiency of monocyte uptake by another population, probably one expressing C3b-binding receptors (C3b was detected on liposomes after incubation with blood plasma). MTX liposomes were shown to have different effects on TNF-α production by activated leukocytes, depending on the structure of the stabilizing molecule.
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Affiliation(s)
- D S Tretiakova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997 Russia
| | - S V Khaidukov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997 Russia
| | - A A Babayants
- Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Healthcare of the Russian Federation, Moscow, 123098 Russia
| | - I S Frolova
- Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Healthcare of the Russian Federation, Moscow, 123098 Russia
| | - O N Shcheglovitova
- Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Healthcare of the Russian Federation, Moscow, 123098 Russia
| | - N R Onishchenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997 Russia
| | - E L Vodovozova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997 Russia
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52
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Makou E, Bailey RG, Johnston H, Parkin JD, Hulme AN, Hähner G, Barlow PN. Combining SPR with atomic-force microscopy enables single-molecule insights into activation and suppression of the complement cascade. J Biol Chem 2019; 294:20148-20163. [PMID: 31719147 PMCID: PMC6937562 DOI: 10.1074/jbc.ra119.010913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/07/2019] [Indexed: 12/05/2022] Open
Abstract
Activation and suppression of the complement system compete on every serum-exposed surface, host or foreign. Potentially harmful outcomes of this competition depend on surface molecules through mechanisms that remain incompletely understood. Combining surface plasmon resonance (SPR) with atomic force microscopy (AFM), here we studied two complement system proteins at the single-molecule level: C3b, the proteolytically activated form of C3, and factor H (FH), the surface-sensing C3b-binding complement regulator. We used SPR to monitor complement initiation occurring through a positive-feedback loop wherein surface-deposited C3b participates in convertases that cleave C3, thereby depositing more C3b. Over multiple cycles of flowing factor B, factor D, and C3 over the SPR chip, we amplified C3b from ∼20 to ∼220 molecules·μm−2. AFM revealed C3b clusters of up to 20 molecules and solitary C3b molecules deposited up to 200 nm away from the clusters. A force of 0.17 ± 0.02 nanonewtons was needed to pull a single FH molecule, anchored to the AFM probe, from its complex with surface-attached C3b. The extent to which FH molecules stretched before detachment varied widely among complexes. Performing force-distance measurements with FH(D1119G), a variant lacking one of the C3b-binding sites and causing atypical hemolytic uremic syndrome, we found that it detached more uniformly and easily. In further SPR experiments, KD values between FH and C3b on a custom-made chip surface were 5-fold tighter than on commercial chips and similar to those on erythrocytes. These results suggest that the chemistry at the surface on which FH acts drives conformational adjustments that are functionally critical.
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Affiliation(s)
- Elisavet Makou
- EaStChem School of Chemistry, University of Edinburgh, Joseph Black Chemistry Building, Edinburgh, Scotland EH9 3FJ, United Kingdom
| | - Richard G Bailey
- EaStChem School of Chemistry, University of St. Andrews, St Andrews, Scotland KY16 9ST, United Kingdom
| | - Heather Johnston
- EaStChem School of Chemistry, University of Edinburgh, Joseph Black Chemistry Building, Edinburgh, Scotland EH9 3FJ, United Kingdom
| | - John D Parkin
- EaStChem School of Chemistry, University of St. Andrews, St Andrews, Scotland KY16 9ST, United Kingdom
| | - Alison N Hulme
- EaStChem School of Chemistry, University of Edinburgh, Joseph Black Chemistry Building, Edinburgh, Scotland EH9 3FJ, United Kingdom
| | - Georg Hähner
- EaStChem School of Chemistry, University of St. Andrews, St Andrews, Scotland KY16 9ST, United Kingdom
| | - Paul N Barlow
- EaStChem School of Chemistry, University of Edinburgh, Joseph Black Chemistry Building, Edinburgh, Scotland EH9 3FJ, United Kingdom .,School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland EH9 3JY, United Kingdom
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53
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Li S, Chi Z, Li W. In vitro toxicity of dimethyl phthalate to human erythrocytes: From the aspects of antioxidant and immune functions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 253:239-245. [PMID: 31319240 DOI: 10.1016/j.envpol.2019.07.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/14/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
In the study, the effects of dimethyl phthalate (DMP) on the antioxidant defense capacity and immune functions of human erythrocytes were experimentally explored. DMP affected the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) and the contents of glutathione (GSH) and malondialdehyde (MDA) in erythrocytes, thus impairing the function of antioxidant defense system of erythrocytes. When DMP concentration increased from 0 to 28 μmol L-1, the SOD and GPX activities were increased firstly and then gradually decreased. When DMP concentration was below 20 μmol L-1, the relative activity of SOD was enhanced by DMP and the effect was known as hormesis. The relative activity of GPX was also increased when the concentration of DMP was below 12 μmol L-1. The CAT activity was more significantly inhibited by DMP than the activities of SOD and GPX, whereas the relative GSH content was increased by DMP. MDA levels were significantly changed after the exposure to DMP (0-24 μmol L-1). The experimental results of the activity of SOD and CAT, and the content of MDA also suggested that DMP could inhibit the immune functions of red blood cells (RBCs), which were further proved by the decrease of two indicators (RBC-C3b and RBC-IC) due to the destruction of C3b receptor with immune adherence function on erythrocyte membrane. The study provides a deep understanding of the toxicity of DMP on erythrocytes.
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Affiliation(s)
- Shixuan Li
- School of Marine Science and Technology, Harbin Institute of Technology, Weihai, 2(#) Wenhua West Road, Weihai 264209, PR China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Zhenxing Chi
- School of Marine Science and Technology, Harbin Institute of Technology, Weihai, 2(#) Wenhua West Road, Weihai 264209, PR China; Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China.
| | - Weiguo Li
- School of Marine Science and Technology, Harbin Institute of Technology, Weihai, 2(#) Wenhua West Road, Weihai 264209, PR China
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54
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Enterina JR, Jung J, Macauley MS. Coordinated roles for glycans in regulating the inhibitory function of CD22 on B cells. Biomed J 2019; 42:218-232. [PMID: 31627864 PMCID: PMC6818156 DOI: 10.1016/j.bj.2019.07.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/19/2019] [Accepted: 07/26/2019] [Indexed: 01/17/2023] Open
Abstract
CD22 is an inhibitory B cell co-receptor that recognizes sialic acid-containing glycoconjugates as ligands. Interactions with its glycan ligands are key to regulating the ability of CD22 to modulate B cell function, the most widely explored of which is antagonizing B cell receptor (BCR) signaling. Most importantly, interactions of CD22 with ligands on the same cell (cis) control the organization of CD22 on the cell surface, which minimizes co-localization with the BCR. In contrast with the modest ability of CD22 to intrinsically dampen BCR signaling, glycan ligands presented on another cell (trans) along with an antigen drawn CD22 and the BCR together within an immunological synapse, strongly inhibiting BCR signaling. New concepts are emerging for how CD22 controls B cell function, such as changes in glycosylation at different stages of B cell differentiation, specifically on GC B cells. Related to these changes, new players, such galectin-9, have been discovered that regulate cell surface nanoclusters of CD22. Roles of glycan ligands in controlling CD22 are the primary focus of this review as we highlight the ability of CD22 to modulate B cell function.
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Affiliation(s)
- Jhon R Enterina
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
| | - Jaesoo Jung
- Department of Chemistry, University of Alberta, Edmonton, Canada
| | - Matthew S Macauley
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada; Department of Chemistry, University of Alberta, Edmonton, Canada.
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55
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Battin C, De Sousa Linhares A, Paster W, Isenman DE, Wahrmann M, Leitner J, Zlabinger GJ, Steinberger P, Hofer J. Neuropilin-1 Acts as a Receptor for Complement Split Products. Front Immunol 2019; 10:2209. [PMID: 31572401 PMCID: PMC6753332 DOI: 10.3389/fimmu.2019.02209] [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: 07/02/2019] [Accepted: 09/02/2019] [Indexed: 01/07/2023] Open
Abstract
Complement split products (CSPs), such as the fragments C4d and C3d, which are generated as a consequence of complement regulatory processes, are established markers for disease activity in autoimmunity or antibody-mediated graft rejection. Since immunoglobulin-like transcript 4 (ILT4) was previously shown to interact with soluble CSPs, but not with CSPs covalently-bound to target surfaces following classical complement activation, the present study aimed to identify novel cellular receptors interacting with covalently-deposited CSPs. By applying an unbiased screening approach using a cDNA mammalian expression library generated from human monocyte-derived dendritic cells and probed with recombinant human C4d, we identified neuropilin-1 (NRP1) as a novel receptor for C4d, C3d, and iC3b. NRP1, a highly conserved type 1 transmembrane protein, plays important roles in the development of the nervous and cardiovascular system as well as in tumorigenesis through interaction with its established binding partners, such as vascular endothelial growth factor (VEGF) and semaphorin 3A (Sema3A). NRP1 is also expressed on immune cells and serves as a marker for murine Tregs. Although NRP1 contains domains homologous to ones found in some complement proteins, it has not been linked to the complement system. We demonstrate that binding of C4d to NRP1 expressing cells was dose-dependent and saturable, and had a KD value of 0.71 μM. Importantly, and in contrast to ILT4, NRP1 interacted with CSPs that were covalently bound to target surfaces in the course of complement activation, therefore representing a classical complement receptor. The binding site of CSPs was mapped to the b1 domain of the coagulation factor V/VIII homology domain of NRP1. Taken together, our results demonstrate a novel role for NRP1 as a receptor for CSPs deposited on surfaces during complement activation. Further work is required to elucidate the functional consequences of the NRP1-CSP interactions in immunity.
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Affiliation(s)
- Claire Battin
- Division of Immune Receptors and T Cell Activation, Center for Pathophysiology, Infectiology, and Immunology, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Annika De Sousa Linhares
- Division of Immune Receptors and T Cell Activation, Center for Pathophysiology, Infectiology, and Immunology, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Wolfgang Paster
- Division of Immune Receptors and T Cell Activation, Center for Pathophysiology, Infectiology, and Immunology, Institute of Immunology, Medical University of Vienna, Vienna, Austria.,Department of Clinical Cell Biology and FACS Core Unit, Children's Cancer Research Institute (CCRI), Vienna, Austria
| | - David E Isenman
- Departments of Biochemistry and Immunology, University of Toronto, Toronto, ON, Canada
| | - Markus Wahrmann
- Division of Nephrology and Dialysis, Department of Internal Medicine III, Medical University Vienna, Vienna, Austria
| | - Judith Leitner
- Division of Immune Receptors and T Cell Activation, Center for Pathophysiology, Infectiology, and Immunology, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Gerhard J Zlabinger
- Division of Clinical and Experimental Immunology, Center for Pathophysiology, Infectiology, and Immunology, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Peter Steinberger
- Division of Immune Receptors and T Cell Activation, Center for Pathophysiology, Infectiology, and Immunology, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - Johannes Hofer
- Division of Nephrology and Dialysis, Department of Internal Medicine III, Medical University Vienna, Vienna, Austria
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56
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Hew BE, Fritzinger DC, Pangburn MK, Vogel CW. Identification of functionally important amino acid sequences in cobra venom factor using human C3/Cobra venom factor hybrid proteins. Toxicon 2019; 167:106-116. [DOI: 10.1016/j.toxicon.2019.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/18/2019] [Accepted: 06/13/2019] [Indexed: 11/28/2022]
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57
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Pedersen DV, Gadeberg TAF, Thomas C, Wang Y, Joram N, Jensen RK, Mazarakis SMM, Revel M, El Sissy C, Petersen SV, Lindorff-Larsen K, Thiel S, Laursen NS, Fremeaux-Bacchi V, Andersen GR. Structural Basis for Properdin Oligomerization and Convertase Stimulation in the Human Complement System. Front Immunol 2019; 10:2007. [PMID: 31507604 PMCID: PMC6713926 DOI: 10.3389/fimmu.2019.02007] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/07/2019] [Indexed: 12/05/2022] Open
Abstract
Properdin (FP) is a positive regulator of the immune system stimulating the activity of the proteolytically active C3 convertase C3bBb in the alternative pathway of the complement system. Here we present two crystal structures of FP and two structures of convertase bound FP. A structural core formed by three thrombospondin repeats (TSRs) and a TB domain harbors the convertase binding site in FP that mainly interacts with C3b. Stabilization of the interaction between the C3b C-terminus and the MIDAS bound Mg2+ in the Bb protease by FP TSR5 is proposed to underlie FP convertase stabilization. Intermolecular contacts between FP and the convertase subunits suggested by the structure were confirmed by binding experiments. FP is shown to inhibit C3b degradation by FI due to a direct competition for a common binding site on C3b. FP oligomers are held together by two sets of intermolecular contacts, where the first is formed by the TB domain from one FP molecule and TSR4 from another. The second and largest interface is formed by TSR1 and TSR6 from the same two FP molecules. Flexibility at four hinges between thrombospondin repeats is suggested to enable the oligomeric, polydisperse, and extended architecture of FP. Our structures rationalize the effects of mutations associated with FP deficiencies and provide a structural basis for the analysis of FP function in convertases and its possible role in pattern recognition.
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Affiliation(s)
- Dennis V. Pedersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Trine A. F. Gadeberg
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Caroline Thomas
- Service d'Oncologie Pédiatrique, CHU Nantes, Hôpital Mère Enfant, Nantes, France
| | - Yong Wang
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Nicolas Joram
- Service de Réanimation Pédiatrique, CHU Nantes, Nantes, France
| | - Rasmus K. Jensen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Sofia M. M. Mazarakis
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Margot Revel
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, USPC, Université Paris Descartes, Université Paris Diderot, Paris, France
| | - Carine El Sissy
- Service d'Immunologie Biologique, Assistance Publique – Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
| | | | - Kresten Lindorff-Larsen
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Nick S. Laursen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
| | - Véronique Fremeaux-Bacchi
- Service d'Immunologie Biologique, Assistance Publique – Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
| | - Gregers R. Andersen
- Department of Molecular Biology and Genetics, Center for Structural Biology, Aarhus University, Aarhus, Denmark
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58
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Ramyar KX, Xu X, White NM, Keightley A, Geisbrecht BV. Expression, purification, and characterization of a human complement component C3 analog that lacks the C-terminal C345c domain. J Immunol Methods 2019; 473:112633. [PMID: 31319063 DOI: 10.1016/j.jim.2019.07.005] [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: 05/15/2019] [Revised: 06/27/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
Abstract
The complement system consists of a series of soluble and cell-surface proteins that serve numerous roles in innate immunity, development, and homeostasis. Despite its many functions, the central event in the complement system is the proteolytic activation of the 185 kDa complement component 3 (C3) into its opsonin and anaphylatoxin fragments known as C3b (175 kDa) and C3a (10 kDa), respectively. The C3 protein is comprised of thirteen separate structural domains, several of which undergo extensive structural rearrangement upon activation to C3b. In addition to this, the C-terminal C345c domain found in C3, C3b, and the terminal degradation product, C3c (135 kDa), appears to adopt multiple conformations relative to the remainder of the molecule. To facilitate various structure/function studies, we designed two C3 analogs that could be activated to a C345c-less, C3c-like state following treatment with Tobacco Etch Virus (TEV) protease. We generated stably transfected Chinese Hamster Ovary (CHO) cell lines that secrete approximately 1.5 mg of the highest-expressing C3 analog per liter of conditioned culture medium. We purified this C3 analog by sequential immobilized metal ion affinity and size exclusion chromatographies, activated the protein by digestion with TEV protease, and purified the resulting C3c analog by a final size exclusion chromatography. The conformations and activities of our C3 and C3c analogs were assessed by measuring their binding profiles to known C3/b/c ligands by surface plasmon resonance. Together, this work demonstrates the feasibility of producing a C3 analog that can be site-specifically activated by an exogenous proteolytic enzyme.
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Affiliation(s)
- Kasra X Ramyar
- Department of Biochemistry & Molecular Biophysics, Kansas State University, 141 Chalmers Hall, 1711 Claflin Road, Manhattan, KS 66506, United States of America
| | - Xin Xu
- Department of Biochemistry & Molecular Biophysics, Kansas State University, 141 Chalmers Hall, 1711 Claflin Road, Manhattan, KS 66506, United States of America
| | - Natalie M White
- Department of Biochemistry & Molecular Biophysics, Kansas State University, 141 Chalmers Hall, 1711 Claflin Road, Manhattan, KS 66506, United States of America
| | - Andrew Keightley
- School of Biological Sciences, University of Missouri-Kansas City, 5100 Rockhill Road, Kansas City, MO 64110, United States of America
| | - Brian V Geisbrecht
- Department of Biochemistry & Molecular Biophysics, Kansas State University, 141 Chalmers Hall, 1711 Claflin Road, Manhattan, KS 66506, United States of America.
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59
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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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60
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Ma Y, Liu Y, Zhang Z, Yang GY. Significance of Complement System in Ischemic Stroke: A Comprehensive Review. Aging Dis 2019; 10:429-462. [PMID: 31011487 PMCID: PMC6457046 DOI: 10.14336/ad.2019.0119] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/19/2019] [Indexed: 12/14/2022] Open
Abstract
The complement system is an essential part of innate immunity, typically conferring protection via eliminating pathogens and accumulating debris. However, the defensive function of the complement system can exacerbate immune, inflammatory, and degenerative responses in various pathological conditions. Cumulative evidence indicates that the complement system plays a critical role in the pathogenesis of ischemic brain injury, as the depletion of certain complement components or the inhibition of complement activation could reduce ischemic brain injury. Although multiple candidates modulating or inhibiting complement activation show massive potential for the treatment of ischemic stroke, the clinical availability of complement inhibitors remains limited. The complement system is also involved in neural plasticity and neurogenesis during cerebral ischemia. Thus, unexpected side effects could be induced if the systemic complement system is inhibited. In this review, we highlighted the recent concepts and discoveries of the roles of different kinds of complement components, such as C3a, C5a, and their receptors, in both normal brain physiology and the pathophysiology of brain ischemia. In addition, we comprehensively reviewed the current development of complement-targeted therapy for ischemic stroke and discussed the challenges of bringing these therapies into the clinic. The design of future experiments was also discussed to better characterize the role of complement in both tissue injury and recovery after cerebral ischemia. More studies are needed to elucidate the molecular and cellular mechanisms of how complement components exert their functions in different stages of ischemic stroke to optimize the intervention of targeting the complement system.
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Affiliation(s)
- Yuanyuan Ma
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yanqun Liu
- 3Department of Neurology, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Zhijun Zhang
- 2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Yuan Yang
- 1Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,2Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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61
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Vasilev VV, Radanova M, Lazarov VJ, Dragon-Durey MA, Fremeaux-Bacchi V, Roumenina LT. Autoantibodies Against C3b-Functional Consequences and Disease Relevance. Front Immunol 2019; 10:64. [PMID: 30761135 PMCID: PMC6361862 DOI: 10.3389/fimmu.2019.00064] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/11/2019] [Indexed: 11/16/2022] Open
Abstract
The complement component C3 is at the heart of the complement cascade. It is a complex protein, which generates different functional activated fragments (C3a, C3b, iC3b, C3c, C3d). C3b is a constituent of the alternative pathway C3 convertase (C3bBb), binds multiple regulators, and receptors, affecting thus the functioning of the immune system. The activated forms of C3 are a target for autoantibodies. This review focuses on the discovery, disease relevance, and functional consequences of the anti-C3b autoantibodies. They were discovered about 70 years ago and named immunoconglutinins. They were found after infections and considered convalescent factors. At the end of the twentieth century IgG against C3b were found in systemic lupus erythematosus and recently in lupus nephritis, correlating with the disease severity and flare. Cases of C3 glomerulopathy and immune complex glomerulonephritis were also reported. These antibodies recognize epitopes, shared between C3(H2O)/C3b/iC3b/C3c and have overt functional activity. They correlate with low plasmatic C3 levels in patients. In vitro, they increase the activity of the alternative pathway C3 convertase, without being C3 nephritic factors. They perturb the binding of the negative regulators Complement Receptor 1 and Factor H. The clear functional consequences and association with disease severity warrant further studies to establish the link between the anti-C3b autoantibodies and tissue injury. Comparative studies with such antibodies, found in patients with infections, may help to uncover their origin and epitopes specificity. Patients with complement overactivation due to presence of anti-C3b antibodies may benefit from therapeutic targeting of C3.
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Affiliation(s)
- Vasil V Vasilev
- Nephrology Clinic, University Hospital "Tsaritsa Yoanna-ISUL," Medical University-Sofia, Sofia, Bulgaria
| | - Maria Radanova
- Department of Biochemistry, Molecular Medicine and Nutrigenomics, Medical University Varna, Varna, Bulgaria
| | - Valentin J Lazarov
- Nephrology Clinic, University Hospital "Tsaritsa Yoanna-ISUL," Medical University-Sofia, Sofia, Bulgaria
| | - Marie-Agnes Dragon-Durey
- Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France.,INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Veronique Fremeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France.,INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Lubka T Roumenina
- INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, Paris, France.,Sorbonne Universités, UPMC Univ Paris 06, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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62
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Heesterbeek DA, Bardoel BW, Parsons ES, Bennett I, Ruyken M, Doorduijn DJ, Gorham RD, Berends ET, Pyne AL, Hoogenboom BW, Rooijakkers SH. Bacterial killing by complement requires membrane attack complex formation via surface-bound C5 convertases. EMBO J 2019; 38:embj.201899852. [PMID: 30643019 PMCID: PMC6376327 DOI: 10.15252/embj.201899852] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 12/05/2018] [Accepted: 12/14/2018] [Indexed: 12/16/2022] Open
Abstract
The immune system kills bacteria by the formation of lytic membrane attack complexes (MACs), triggered when complement enzymes cleave C5. At present, it is not understood how the MAC perturbs the composite cell envelope of Gram-negative bacteria. Here, we show that the role of C5 convertase enzymes in MAC assembly extends beyond the cleavage of C5 into the MAC precursor C5b. Although purified MAC complexes generated from preassembled C5b6 perforate artificial lipid membranes and mammalian cells, these components lack bactericidal activity. In order to permeabilize both the bacterial outer and inner membrane and thus kill a bacterium, MACs need to be assembled locally by the C5 convertase enzymes. Our data indicate that C5b6 rapidly loses the capacity to form bactericidal pores; therefore, bacterial killing requires both in situ conversion of C5 and immediate insertion of C5b67 into the membrane. Using flow cytometry and atomic force microscopy, we show that local assembly of C5b6 at the bacterial surface is required for the efficient insertion of MAC pores into bacterial membranes. These studies provide basic molecular insights into MAC assembly and bacterial killing by the immune system.
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Affiliation(s)
- Dani Ac Heesterbeek
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Bart W Bardoel
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Edward S Parsons
- London Centre for Nanotechnology, University College London, London, UK
| | - Isabel Bennett
- London Centre for Nanotechnology, University College London, London, UK
| | - Maartje Ruyken
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Dennis J Doorduijn
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Ronald D Gorham
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Evelien Tm Berends
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Alice Lb Pyne
- London Centre for Nanotechnology, University College London, London, UK
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London, UK.,Department of Physics and Astronomy, University College London, London, UK
| | - Suzan Hm Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
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63
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Yang Y, Back CR, Gräwert MA, Wahid AA, Denton H, Kildani R, Paulin J, Wörner K, Kaiser W, Svergun DI, Sartbaeva A, Watts AG, Marchbank KJ, van den Elsen JMH. Utilization of Staphylococcal Immune Evasion Protein Sbi as a Novel Vaccine Adjuvant. Front Immunol 2019; 9:3139. [PMID: 30687332 PMCID: PMC6336717 DOI: 10.3389/fimmu.2018.03139] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 12/19/2018] [Indexed: 02/04/2023] Open
Abstract
Co-ligation of the B cell antigen receptor with complement receptor 2 on B-cells via a C3d-opsonised antigen complex significantly lowers the threshold required for B cell activation. Consequently, fusions of antigens with C3d polymers have shown great potential in vaccine design. However, these linear arrays of C3d multimers do not mimic the natural opsonisation of antigens with C3d. Here we investigate the potential of using the unique complement activating characteristics of Staphylococcal immune-evasion protein Sbi to develop a pro-vaccine approach that spontaneously coats antigens with C3 degradation products in a natural way. We show that Sbi rapidly triggers the alternative complement pathway through recruitment of complement regulators, forming tripartite complexes that act as competitive antagonists of factor H, resulting in enhanced complement consumption. These functional results are corroborated by the structure of the complement activating Sbi-III-IV:C3d:FHR-1 complex. Finally, we demonstrate that Sbi, fused with Mycobacterium tuberculosis antigen Ag85b, causes efficient opsonisation with C3 fragments, thereby enhancing the immune response significantly beyond that of Ag85b alone, providing proof of concept for our pro-vaccine approach.
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Affiliation(s)
- Yi Yang
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Catherine R Back
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Melissa A Gräwert
- Hamburg Unit, European Molecular Biology Laboratory, Deutsches Elektronen-Synchrotron, Hamburg, Germany
| | - Ayla A Wahid
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Harriet Denton
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Rebecca Kildani
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | - Joshua Paulin
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
| | | | | | - Dmitri I Svergun
- Hamburg Unit, European Molecular Biology Laboratory, Deutsches Elektronen-Synchrotron, Hamburg, Germany
| | - Asel Sartbaeva
- Department of Chemistry, University of Bath, Bath, United Kingdom
| | - Andrew G Watts
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
| | - Kevin J Marchbank
- Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
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64
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King BC, Kulak K, Krus U, Rosberg R, Golec E, Wozniak K, Gomez MF, Zhang E, O'Connell DJ, Renström E, Blom AM. Complement Component C3 Is Highly Expressed in Human Pancreatic Islets and Prevents β Cell Death via ATG16L1 Interaction and Autophagy Regulation. Cell Metab 2019; 29:202-210.e6. [PMID: 30293775 DOI: 10.1016/j.cmet.2018.09.009] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 07/23/2018] [Accepted: 09/07/2018] [Indexed: 01/25/2023]
Abstract
We show here that human pancreatic islets highly express C3, which is both secreted and present in the cytosol. Within isolated human islets, C3 expression correlates with type 2 diabetes (T2D) donor status, HbA1c, and inflammation. Islet C3 expression is also upregulated in several rodent diabetes models. C3 interacts with ATG16L1, which is essential for autophagy. Autophagy relieves cellular stresses faced by β cells during T2D and maintains cellular homeostasis. C3 knockout in clonal β cells impaired autophagy and led to increased apoptosis after exposure of cells to palmitic acid and IAPP. In the absence of C3, autophagosomes do not undergo fusion with lysosomes. Thus, C3 may be upregulated in islets during T2D as a cytoprotective factor against β cell dysfunction caused by impaired autophagy. Therefore, we revealed a previously undescribed intracellular function for C3, connecting the complement system directly to autophagy, with a broad potential importance in other diseases and cell types.
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Affiliation(s)
- Ben C King
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214-28 Malmö, Sweden
| | - Klaudia Kulak
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214-28 Malmö, Sweden
| | - Ulrika Krus
- Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, 214-28 Malmö, Sweden
| | - Rebecca Rosberg
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214-28 Malmö, Sweden
| | - Ewelina Golec
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214-28 Malmö, Sweden
| | - Katarzyna Wozniak
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214-28 Malmö, Sweden
| | - Maria F Gomez
- Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, 214-28 Malmö, Sweden
| | - Enming Zhang
- Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, 214-28 Malmö, Sweden
| | - David J O'Connell
- School of Biomolecular & Biomedical Science, Conway Institute, University College Dublin, Dublin, Ireland
| | - Erik Renström
- Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, 214-28 Malmö, Sweden
| | - Anna M Blom
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, 214-28 Malmö, Sweden.
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65
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Omoyinmi E, Mohamoud I, Gilmour K, Brogan PA, Eleftheriou D. Cutaneous Vasculitis and Digital Ischaemia Caused by Heterozygous Gain-of-Function Mutation in C3. Front Immunol 2018; 9:2524. [PMID: 30443255 PMCID: PMC6221951 DOI: 10.3389/fimmu.2018.02524] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/12/2018] [Indexed: 12/22/2022] Open
Abstract
It is now increasingly recognized that some monogenic autoinflammatory diseases and immunodeficiencies cause vasculitis, although genetic causes of vasculitis are extremely rare. We describe a child of non-consanguineous parents who presented with cutaneous vasculitis, digital ischaemia and hypocomplementaemia. A heterozygous p.R1042G gain-of-function mutation (GOF) in the complement component C3 gene was identified as the cause, resulting in secondary C3 consumption and complete absence of alternative complement pathway activity, decreased classical complement activity, and low levels of serum C3 with normal C4 levels. The same heterozygous mutation and immunological defects were also identified in another symptomatic sibling and his father. C3 deficiency due GOF C3 mutations is thus now added to the growing list of monogenic causes of vasculitis and should always be considered in vasculitis patients found to have persistently low levels of C3 with normal C4.
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Affiliation(s)
- Ebun Omoyinmi
- Infection, Inflammation and Rheumatology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Iman Mohamoud
- Infection, Inflammation and Rheumatology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
| | - Kimberly Gilmour
- Clinical Immunology Laboratory, Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Paul A Brogan
- Infection, Inflammation and Rheumatology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Despina Eleftheriou
- Infection, Inflammation and Rheumatology Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.,Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom.,Centre for Adolescent Rheumatology, Arthritis Research UK, University College London (UCL), University College London Hospital (UCLH) and Great Ormond Street Hospital (GOSH), London, United Kingdom
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66
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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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67
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Zhang J, Li S, Hu S, Yu J, Xiang Y. Association between genetic variation of complement C3 and the susceptibility to advanced age-related macular degeneration: a meta-analysis. BMC Ophthalmol 2018; 18:274. [PMID: 30352574 PMCID: PMC6199710 DOI: 10.1186/s12886-018-0945-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 10/16/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The purpose of this study is to discuss whether genetic variants (rs2230199, rs1047286, rs2230205, and rs2250656) in the C3 gene account for a significant risk of advanced AMD. METHODS We performed a meta-analysis using electronic databases to search relevant articles. A total of 40 case-control studies from 38 available articles (20,673 cases and 20,025 controls) were included in our study. RESULTS In our meta-analysis, the pooled results showed that the carriage of G allele for rs2230199 and the T allele for rs1047286 had a tendency to the risk of advanced AMD (OR = 1.49, 95% CI = 1.39-1.59, P < 0.001; OR = 1.45, 95% CI = 1.37-1.54, P < 0.001). Moreover, in the subgroup analysis based on ethnicity, rs2230199 and rs1047286 polymorphisms were more likely to be a predictor of response for Caucasian region (OR = 1.48, 95% CI = 1.38-1.59, P < 0.001; OR = 1.45, 95% CI = 1.37-1.54, P < 0.001). Besides, pooled results suggested that the G allele of rs2230199 could confer susceptibility to advanced AMD in Middle East (OR = 1.62, 95% CI = 1.33-1.97, P < 0.001). CONCLUSION In our meta-analysis, C3 genetic polymorphisms unveiled a positive effect on the risk of advanced AMD, especially in Caucasians. Furthermore, numerous well-designed studies with large sample-size are required to validate this conclusion.
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Affiliation(s)
- Jun Zhang
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, NO, 26 Shengli Street, Wuhan, 430014, Hubei Province, China
| | - Shuang Li
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, NO, 26 Shengli Street, Wuhan, 430014, Hubei Province, China
| | - Shuqiong Hu
- Department of Ophthalmology, the Jingzhou aier eye hospital, Jingzhou, Hubei Province, China
| | - Jiguo Yu
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, NO, 26 Shengli Street, Wuhan, 430014, Hubei Province, China
| | - Yi Xiang
- Department of Ophthalmology, the Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, NO, 26 Shengli Street, Wuhan, 430014, Hubei Province, China.
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68
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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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69
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Heesterbeek DAC, Angelier ML, Harrison RA, Rooijakkers SHM. Complement and Bacterial Infections: From Molecular Mechanisms to Therapeutic Applications. J Innate Immun 2018; 10:455-464. [PMID: 30149378 PMCID: PMC6784045 DOI: 10.1159/000491439] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 06/21/2018] [Accepted: 06/21/2018] [Indexed: 12/22/2022] Open
Abstract
Complement is a complex protein network of plasma, and an integral part of the innate immune system. Complement activation results in the rapid clearance of bacteria by immune cells, and direct bacterial killing via large pore-forming complexes. Here we review important recent discoveries in the complement field, focusing on interactions relevant for the defense against bacteria. Understanding the molecular interplay between complement and bacteria is of great importance for future therapies for infectious and inflammatory diseases. Antibodies that support complement-dependent bacterial killing are of interest for the development of alternative therapies to treat infections with antibiotic-resistant bacteria. Furthermore, a variety of novel therapeutic complement inhibitors have been developed to prevent unwanted complement activation in autoimmune inflammatory diseases. A better understanding of how such inhibitors may increase the risk of bacterial infections is essential if such therapies are to be successful.
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Affiliation(s)
- Dani A C Heesterbeek
- Department of Medical Microbiology, Utrecht University Medical Center, Utrecht, The Netherlands
| | - Mathieu L Angelier
- Department of Medical Microbiology, Utrecht University Medical Center, Utrecht, The Netherlands
| | - Richard A Harrison
- Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
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70
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Zwarthoff SA, Berends ETM, Mol S, Ruyken M, Aerts PC, Józsi M, de Haas CJC, Rooijakkers SHM, Gorham RD. Functional Characterization of Alternative and Classical Pathway C3/C5 Convertase Activity and Inhibition Using Purified Models. Front Immunol 2018; 9:1691. [PMID: 30083158 PMCID: PMC6064732 DOI: 10.3389/fimmu.2018.01691] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/10/2018] [Indexed: 12/24/2022] Open
Abstract
Complement is essential for the protection against infections; however, dysregulation of complement activation can cause onset and progression of numerous inflammatory diseases. Convertase enzymes play a central role in complement activation and produce the key mediators of complement: C3 convertases cleave C3 to generate chemoattractant C3a and label target cells with C3b, which promotes phagocytosis; C5 convertases cleave C5 into chemoattractant C5a, and C5b, which drives formation of the membrane attack complex. Since convertases mediate nearly all complement effector functions, they are ideal targets for therapeutic complement inhibition. A unique feature of convertases is their covalent attachment to target cells, which effectively confines complement activation to the cell surface. However, surface localization precludes detailed analysis of convertase activation and inhibition. In our previous work, we developed a model system to form purified alternative pathway (AP) C5 convertases on C3b-coated beads and quantify C5 conversion via functional analysis of released C5a. Here, we developed a C3aR cell reporter system that enables functional discrimination between C3 and C5 convertases. By regulating the C3b density on the bead surface, we observe that high C3b densities are important for conversion of C5, but not C3, by AP convertases. Screening of well-characterized complement-binding molecules revealed that differential inhibition of AP C3 convertases (C3bBb) and C5 convertases [C3bBb(C3b)n] is possible. Although both convertases contain C3b, the C3b-binding molecules Efb-C/Ecb and FHR5 specifically inhibit C5 conversion. Furthermore, using a new classical pathway convertase model, we show that these C3b-binding proteins not only block AP C3/C5 convertases but also inhibit formation of a functional classical pathway C5 convertase under well-defined conditions. Our models enable functional characterization of purified convertase enzymes and provide a platform for the identification and development of specific convertase inhibitors for treatment of complement-mediated disorders.
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Affiliation(s)
- Seline A Zwarthoff
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Evelien T M Berends
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Sanne Mol
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Maartje Ruyken
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Piet C Aerts
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Mihály Józsi
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Carla J C de Haas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
| | - Ronald D Gorham
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands
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71
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Jensen RK, Pihl R, Gadeberg TAF, Jensen JK, Andersen KR, Thiel S, Laursen NS, Andersen GR. A potent complement factor C3-specific nanobody inhibiting multiple functions in the alternative pathway of human and murine complement. J Biol Chem 2018; 293:6269-6281. [PMID: 29497000 PMCID: PMC5925797 DOI: 10.1074/jbc.ra117.001179] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/07/2018] [Indexed: 12/30/2022] Open
Abstract
The complement system is a complex, carefully regulated proteolytic cascade for which suppression of aberrant activation is of increasing clinical relevance, and inhibition of the complement alternative pathway is a subject of intense research. Here, we describe the nanobody hC3Nb1 that binds to multiple functional states of C3 with subnanomolar affinity. The nanobody causes a complete shutdown of alternative pathway activity in human and murine serum when present in concentrations comparable with that of C3, and hC3Nb1 is shown to prevent proconvertase assembly, as well as binding of the C3 substrate to C3 convertases. Our crystal structure of the C3b-hC3Nb1 complex and functional experiments demonstrate that proconvertase formation is blocked by steric hindrance between the nanobody and an Asn-linked glycan on complement factor B. In addition, hC3Nb1 is shown to prevent factor H binding to C3b, rationalizing its inhibition of factor I activity. Our results identify hC3Nb1 as a versatile, inexpensive, and powerful inhibitor of the alternative pathway in both human and murine in vitro model systems of complement activation.
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Affiliation(s)
| | - Rasmus Pihl
- Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | | | - Jan K. Jensen
- From the Departments of Molecular Biology and Genetics and
| | | | - Steffen Thiel
- Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | | | - Gregers R. Andersen
- From the Departments of Molecular Biology and Genetics and , To whom correspondence should be addressed:
Dept. of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark. Tel.:
45-5144-6530; Fax:
45-8619-6500; E-mail:
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72
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Martínez D, Díaz-Ibarrola D, Vargas-Lagos C, Oyarzún R, Pontigo JP, Muñoz JLP, Yáñez AJ, Vargas-Chacoff L. Immunological response of the Sub-Antarctic Notothenioid fish Eleginops maclovinus injected with two strains of Piscirickettsia salmonis. FISH & SHELLFISH IMMUNOLOGY 2018; 75:139-148. [PMID: 29421586 DOI: 10.1016/j.fsi.2018.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/03/2018] [Accepted: 01/11/2018] [Indexed: 06/08/2023]
Abstract
Eleginops maclovinus is an endemic fish to Chile that lives in proximity to salmonid culture centers, feeding off of uneaten pellet and salmonid feces. Occurring in the natural environment, this interaction between native and farmed fish could result in the horizontal transmission of pathogens affecting the aquaculture industry. The aim of this study was to evaluate the innate and adaptive immune responses of E. maclovinus challenged with P. salmonis. Treatment injections (in duplicate) were as follows: control (100 μL of culture medium), wild type LF-89 strain (100 μL, 1 × 108 live bacteria), and antibiotic resistant strain Austral-005 (100 μL, 1 × 108 live bacteria). The fish were sampled at various time-points during the 35-day experimental period. The gene expression of TLRs (1, 5, and 8), NLRCs (3 and 5), C3, IL-1β, MHCII, and IgMs were significantly modulated during the experimental period in both the spleen and gut (excepting TLR1 and TLR8 spleen expressions), with tissue-specific expression profiles and punctual differences between the injected strains. Anti-P. salmonis antibodies increased in E. maclovinus serum from day 14-28 for the LF-89 strain and from day 14-35 for the Austral-005 strain. These results suggest temporal activation of the innate and adaptive immune responses in E. maclovinus tissues when injected by distinct P. salmonis strains. The Austral-005 strain did not always cause the greatest increases/decreases in the number of transcripts, so the magnitude of the observed immune response (mRNA) may not be related to antibiotic resistance. This is the first immunological study to relate a pathogen widely studied in salmonids with a native fish.
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Affiliation(s)
- D Martínez
- Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Fisiología de Peces, Universidad Austral de Chile, Valdivia, Chile; Escuela de Graduados, Programa de Doctorado en Ciencias de l6a Acuicultura, Universidad Austral de Chile, Av. Los Pinos s/n Balneario Pelluco, Puerto Montt, Chile; Centro Fondap de Investigación de Altas Latitudes (IDEAL), Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
| | - D Díaz-Ibarrola
- Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Fisiología de Peces, Universidad Austral de Chile, Valdivia, Chile
| | - C Vargas-Lagos
- Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Fisiología de Peces, Universidad Austral de Chile, Valdivia, Chile; Escuela de Graduados, Programa de Magister en Microbiología, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap Interdisciplinary Center for Aquaculture Research (INCAR), Universidad Austral de Chile, Valdivia, Chile
| | - R Oyarzún
- Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Fisiología de Peces, Universidad Austral de Chile, Valdivia, Chile; Escuela de Graduados, Programa de Doctorado en Ciencias de l6a Acuicultura, Universidad Austral de Chile, Av. Los Pinos s/n Balneario Pelluco, Puerto Montt, Chile; Centro Fondap de Investigación de Altas Latitudes (IDEAL), Universidad Austral de Chile, Casilla 567, Valdivia, Chile
| | - J P Pontigo
- Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Fisiología de Peces, Universidad Austral de Chile, Valdivia, Chile
| | - J L P Muñoz
- Centro de Investigación y Desarrollo i ∼ mar, Universidad de los Lagos, Casilla 557, Puerto Montt, Chile
| | - A J Yáñez
- Centro Fondap Interdisciplinary Center for Aquaculture Research (INCAR), Universidad Austral de Chile, Valdivia, Chile; Instituto de Bioquímica y Microbiología, Universidad Austral de Chile, Valdivia, Chile
| | - L Vargas-Chacoff
- Instituto de Ciencias Marinas y Limnológicas, Laboratorio de Fisiología de Peces, Universidad Austral de Chile, Valdivia, Chile; Centro Fondap de Investigación de Altas Latitudes (IDEAL), Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
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Abstract
Cobra venom factor (CVF) is the complement-activating protein in cobra venom. Humanized CVF (hCVF) is a human C3 derivative where the C-terminal 168 amino acid residues were replaced with the homologous sequence from CVF. hCVF has been shown in multiple models of disease with complement pathology to be a promising therapeutic agent, with no observed adverse effects. Here we describe the antibody response to hCVF in two different strains of mice. hCVF was able to repeatedly decomplement the mice after four injections in weekly intervals, demonstrating the absence of a neutralizing antibody response. In contrast, natural CVF caused decomplementation in all mice only after the first administration. After two additional administrations of natural CVF, decomplementation was inconsistent and varied tremendously from mouse to mouse. After the fourth administration, natural CVF was essentially unable to deplete complement, consistent with the known generation of a neutralizing antibody response. We also analyzed the IgG antibody response to hCVF. There was great variation, with approximately one quarter of the mice exhibiting non-detectable levels of anti-hCVF IgG, and another quarter very low levels. The levels of anti-hCVF IgG did not correlate with the levels of remaining C3. The anti-hCVF antibodies cross-reacted with natural CVF, recombinant CVF, and human C3. Whereas overall the level of anti-hCVF IgG cross-reacting with human C3 was lower compared to rCVF or nCVF, mice with higher levels of anti-hCVF IgG exhibited higher binding to CVF and human C3, excluding the possibility that higher antibody levels reflect preferential immunogenicity of CVF-specific or human C3-specific epitopes.
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74
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Łukawska E, Polcyn-Adamczak M, Niemir ZI. The role of the alternative pathway of complement activation in glomerular diseases. Clin Exp Med 2018; 18:297-318. [DOI: 10.1007/s10238-018-0491-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 02/12/2018] [Indexed: 01/20/2023]
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75
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Abstract
INTRODUCTION Therapeutic modulation of complement activation is considered as a promising approach for the treatment of host tissue damage in several inflammatory and autoimmune diseases. Complement component protein C3 is a particularly attractive drug target for complement inhibitors, due to its central role in three pathways of complement activation cascade. Areas covered: The author provides a comprehensive review on compstatin family peptides which have been discovered and optimized as potent and selective C3 inhibitors via a combination of chemical, biophysical and computational approaches. New generations of the compstatin family with improved potency and therapeutic properties have been developed in recent years. Over two decades, compstatin demonstrated therapeutic potential as a first-of-its-kind complement inhibitor in a series of disease models, with encouraging efforts in clinical trials. Expert opinion: Compstatin holds promise for new therapeutic implications in blocking the effect of the complement cascade in a variety of disease conditions. The development of cost-effective treatment options with suitable dosing route and schedule will be critical for patients with complement mediated chronic diseases.
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Affiliation(s)
- Yijun Huang
- a WuXi AppTec Inc ., Philadelphia , PA , USA
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76
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Tretiakova DS, Onishchenko NR, Vostrova AG, Vodovozova EL. Interactions of liposomes carrying lipophilic prodrugs in the bilayer with blood plasma proteins. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2018. [DOI: 10.1134/s1068162017060139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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77
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Zouhir S, Robert-Genthon M, Trindade DM, Job V, Nedeljković M, Breyton C, Ebel C, Attrée I, Dessen A. Assembly of an atypical α-macroglobulin complex from Pseudomonas aeruginosa. Sci Rep 2018; 8:527. [PMID: 29323132 PMCID: PMC5764988 DOI: 10.1038/s41598-017-18083-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 12/01/2017] [Indexed: 11/09/2022] Open
Abstract
Alpha-2-macroglobulins (A2Ms) are large spectrum protease inhibitors that are major components of the eukaryotic immune system. Pathogenic and colonizing bacteria, such as the opportunistic pathogen Pseudomonas aeruginosa, also carry structural homologs of eukaryotic A2Ms. Two types of bacterial A2Ms have been identified: Type I, much like the eukaryotic form, displays a conserved thioester that is essential for protease targeting, and Type II, which lacks the thioester and to date has been poorly studied despite its ubiquitous presence in Gram-negatives. Here we show that MagD, the Type II A2M from P. aeruginosa that is expressed within the six-gene mag operon, specifically traps a target protease despite the absence of the thioester motif, comforting its role in protease inhibition. In addition, analytical ultracentrifugation and small angle scattering show that MagD forms higher order complexes with proteins expressed in the same operon (MagA, MagB, and MagF), with MagB playing the key stabilization role. A P. aeruginosa strain lacking magB cannot stably maintain MagD in the bacterial periplasm, engendering complex disruption. This suggests a regulated mechanism of Mag complex formation and stabilization that is potentially common to numerous Gram-negative organisms, and that plays a role in periplasm protection from proteases during infection or colonization.
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Affiliation(s)
- Samira Zouhir
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, São Paulo, Brazil
| | - Mylène Robert-Genthon
- University Grenoble Alpes, Bacterial Pathogenesis and Cellular Responses Group, Institut de Biosciences et Biotechnologies de Grenoble (BIG), Grenoble, France
| | | | - Viviana Job
- University Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38000, Grenoble, France
| | - Marko Nedeljković
- University Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38000, Grenoble, France
| | - Cécile Breyton
- University Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38000, Grenoble, France
| | - Christine Ebel
- University Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38000, Grenoble, France
| | - Ina Attrée
- University Grenoble Alpes, Bacterial Pathogenesis and Cellular Responses Group, Institut de Biosciences et Biotechnologies de Grenoble (BIG), Grenoble, France
| | - Andréa Dessen
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, São Paulo, Brazil. .,University Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), F-38000, Grenoble, France.
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78
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Complement and Immunoglobulin Biology Leading to Clinical Translation. Hematology 2018. [DOI: 10.1016/b978-0-323-35762-3.00024-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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79
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Irmscher S, Döring N, Halder LD, Jo EAH, Kopka I, Dunker C, Jacobsen ID, Luo S, Slevogt H, Lorkowski S, Beyersdorf N, Zipfel PF, Skerka C. Kallikrein Cleaves C3 and Activates Complement. J Innate Immun 2017; 10:94-105. [PMID: 29237166 DOI: 10.1159/000484257] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/14/2017] [Indexed: 12/11/2022] Open
Abstract
The human plasma contact system is an immune surveillance system activated by the negatively charged surfaces of bacteria and fungi and includes the kallikrein-kinin, the coagulation, and the fibrinolytic systems. Previous work shows that the contact system also activates complement, and that plasma enzymes like kallikrein, plasmin, thrombin, and FXII are involved in the activation process. Here, we show for the first time that kallikrein cleaves the central complement component C3 directly to yield active components C3b and C3a. The cleavage site within C3 is identical to that recognized by the C3 convertase. Also, kallikrein-generated C3b forms C3 convertases, which trigger the C3 amplification loop. Since kallikrein also cleaves factor B to yield Bb and Ba, kallikrein alone can trigger complement activation. Kallikrein-generated C3 convertases are inhibited by factor H; thus, the kallikrein activation pathway merges with the amplification loop of the alternative pathway. Taken together, these data suggest that activation of the contact system locally enhances complement activation on cell surfaces. The human pathogenic microbe Candida albicans activates the contact system in normal human serum. However, C. albicans immediately recruits factor H to the surface, thereby evading the alternative and likely kallikrein-mediated complement pathways.
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Affiliation(s)
- Sarah Irmscher
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
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Iyer A, Xu W, Reid RC, Fairlie DP. Chemical Approaches to Modulating Complement-Mediated Diseases. J Med Chem 2017; 61:3253-3276. [DOI: 10.1021/acs.jmedchem.7b00882] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Abishek Iyer
- Centre for Inflammation and Disease Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Weijun Xu
- ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert C. Reid
- ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David P. Fairlie
- Centre for Inflammation and Disease Research, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
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81
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de Jorge EG, Yebenes H, Serna M, Tortajada A, Llorca O, de Córdoba SR. How novel structures inform understanding of complement function. Semin Immunopathol 2017; 40:3-14. [PMID: 28808775 DOI: 10.1007/s00281-017-0643-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/03/2017] [Indexed: 11/30/2022]
Abstract
During the last decade, the complement field has experienced outstanding advancements in the mechanistic understanding of how complement activators are recognized, what C3 activation means, how protein complexes like the C3 convertases and the membrane attack complex are assembled, and how positive and negative complement regulators perform their function. All of this has been made possible mostly because of the contributions of structural biology to the study of the complement components. The wealth of novel structural data has frequently provided support to previously held knowledge, but often has added alternative and unexpected insights into complement function. Here, we will review some of these findings focusing in the alternative and terminal complement pathways.
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Affiliation(s)
- Elena Goicoechea de Jorge
- Department of Microbiology I (Immunology), Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Hugo Yebenes
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Marina Serna
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Agustín Tortajada
- Department of Microbiology I (Immunology), Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Oscar Llorca
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.,Structural Biology Programme, CNIO, C/ Melchor Fernández Almagro 3, 28029, Madrid, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain. .,Ciber de Enfermedades Raras, Madrid, Spain.
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82
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Bayly-Jones C, Bubeck D, Dunstone MA. The mystery behind membrane insertion: a review of the complement membrane attack complex. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160221. [PMID: 28630159 PMCID: PMC5483522 DOI: 10.1098/rstb.2016.0221] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2016] [Indexed: 12/14/2022] Open
Abstract
The membrane attack complex (MAC) is an important innate immune effector of the complement terminal pathway that forms cytotoxic pores on the surface of microbes. Despite many years of research, MAC structure and mechanism of action have remained elusive, relying heavily on modelling and inference from biochemical experiments. Recent advances in structural biology, specifically cryo-electron microscopy, have provided new insights into the molecular mechanism of MAC assembly. Its unique 'split-washer' shape, coupled with an irregular giant β-barrel architecture, enable an atypical mechanism of hole punching and represent a novel system for which to study pore formation. This review will introduce the complement terminal pathway that leads to formation of the MAC. Moreover, it will discuss how structures of the pore and component proteins underpin a mechanism for MAC function, modulation and inhibition.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Charles Bayly-Jones
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
| | - Doryen Bubeck
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW2 7AZ, UK
| | - Michelle A Dunstone
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
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83
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Yorulmaz Avsar S, Jackman JA, Kim MC, Yoon BK, Hunziker W, Cho NJ. Immobilization Strategies for Functional Complement Convertase Assembly at Lipid Membrane Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:7332-7342. [PMID: 28683197 DOI: 10.1021/acs.langmuir.7b01465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The self-assembly formation of complement convertases-essential biomacromolecular complexes that amplify innate immune responses-is triggered by protein adsorption. Herein, a supported lipid bilayer platform was utilized to investigate the effects of covalent and noncovalent tethering strategies on the self-assembly of alternative pathway C3 convertase components, starting with C3b protein adsorption followed bythe addition of factors B and D. Quartz crystal microbalance-dissipation (QCM-D) experiments measured the real-time kinetics of convertase assembly onto supported lipid bilayers. The results demonstrate that the nature of C3b immobilization onto supported lipid bilayers is a key factor governing convertase assembly. The covalent attachment of C3b to maleimide-functionalized supported lipid bilayers promoted the self-assembly of functional C3 convertase in the membrane-associated state and further enabled successful evaluation of a clinically relevant complement inhibitor, compstatin. By contrast, noncovalent attachment of C3b to negatively charged supported lipid bilayers also permitted C3b protein uptake, albeit membrane-associated C3b did not support convertase assembly in this case. Taken together, the findings in this work demonstrate that the attachment scheme for immobilizing C3b protein at lipid membrane interfaces is critical for downstream C3 convertase assembly, thereby offering guidance for the design and evaluation of membrane-associated biomacromolecular complexes.
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Affiliation(s)
- Saziye Yorulmaz Avsar
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798 Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, Singapore 637553, Singapore
- Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore 138673, Singapore
| | - Joshua A Jackman
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798 Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, Singapore 637553, Singapore
| | - Min Chul Kim
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798 Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, Singapore 637553, Singapore
| | - Bo Kyeong Yoon
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798 Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, Singapore 637553, Singapore
| | - Walter Hunziker
- Institute of Molecular and Cell Biology, Agency for Science Technology and Research , Singapore 138673, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore , Singapore 117599, Singapore
- Singapore Eye Research Institute , Singapore 169856, Singapore
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue, Singapore 639798 Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University , 50 Nanyang Drive, Singapore 637553, Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University , 62 Nanyang Drive, Singapore 637459, Singapore
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84
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Hovingh ES, van den Broek B, Kuipers B, Pinelli E, Rooijakkers SHM, Jongerius I. Acquisition of C1 inhibitor by Bordetella pertussis virulence associated gene 8 results in C2 and C4 consumption away from the bacterial surface. PLoS Pathog 2017; 13:e1006531. [PMID: 28742139 PMCID: PMC5542704 DOI: 10.1371/journal.ppat.1006531] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/03/2017] [Accepted: 07/13/2017] [Indexed: 12/12/2022] Open
Abstract
Whooping cough, or pertussis, is a contagious disease of the respiratory tract that is re-emerging worldwide despite high vaccination coverage. The causative agent of this disease is the Gram-negative Bordetella pertussis. Knowledge on complement evasion strategies of this pathogen is limited. However, this is of great importance for future vaccine development as it has become apparent that a novel pertussis vaccine is needed. Here, we unravel the effect of Virulence associated gene 8 (Vag8) of B. pertussis on the human complement system at the molecular level. We show that both recombinant and endogenously secreted Vag8 inhibit complement deposition on the bacterial surface at the level of C4b. We reveal that Vag8 binding to human C1-inhibitor (C1-inh) interferes with the binding of C1-inh to C1s, C1r and MASP-2, resulting in the release of active proteases that subsequently cleave C2 and C4 away from the bacterial surface. We demonstrate that the depletion of these complement components in the bacterial surrounding and subsequent decreased deposition on B. pertussis leads to less complement-mediated bacterial killing. Vag8 is the first protein described that specifically prevents C1s, C1r and MASP-2 binding to C1-inh and thereby mediates complement consumption away from the bacterial surface. Unravelling the mechanism of this unique complement evasion strategy of B. pertussis is one of the first steps towards understanding the interactions between the first line of defense complement and B. pertussis. Despite wide-spread vaccination, whooping cough caused by the Gram-negative bacterium Bordetella pertussis remains a public health problem and has been re-emerging in the past decades. To this end, new vaccination strategies are being explored including the use of complement evasion molecules as vaccine candidates. Autotransporter Virulence associated gene 8 (Vag8) was previously shown to be involved in complement evasion. However, the molecular mechanism of this immune evasion was not understood. Considering knowledge on molecular mechanisms is crucial for further studies regarding vaccine development, we investigated the underlying mechanism of Vag8 induced complement evasion of B. pertussis. We show that both recombinant Vag8 as well as endogenously secreted Vag8 inhibits complement activation via the classical and lectin complement pathway at the level of C4 and C2. We identified a novel bacterial complement evasion strategy initiated by the binding of Vag8 to C1-inhibitor. This binding interferes with the interactions between C1-inhibitor and the proteases C1s, C1r and MASP-2 resulting in the release of active proteases that cleave C4 and C2 away from the bacterial surface. This environmental consumption of C4 and C2 leads to decreased complement deposition on the bacterial surface and hence inhibits complement-mediated killing of B. pertussis.
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Affiliation(s)
- Elise S. Hovingh
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- Centre for Infectious Disease Control, National institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Bryan van den Broek
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Betsy Kuipers
- Centre for Infectious Disease Control, National institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Elena Pinelli
- Centre for Infectious Disease Control, National institute for Public Health and the Environment, Bilthoven, The Netherlands
| | - Suzan H. M. Rooijakkers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ilse Jongerius
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- Centre for Infectious Disease Control, National institute for Public Health and the Environment, Bilthoven, The Netherlands
- * E-mail:
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85
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Xue X, Wu J, Ricklin D, Forneris F, Di Crescenzio P, Schmidt CQ, Granneman J, Sharp TH, Lambris JD, Gros P. Regulator-dependent mechanisms of C3b processing by factor I allow differentiation of immune responses. Nat Struct Mol Biol 2017; 24:643-651. [PMID: 28671664 DOI: 10.1038/nsmb.3427] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/02/2017] [Indexed: 12/26/2022]
Abstract
The complement system labels microbes and host debris for clearance. Degradation of surface-bound C3b is pivotal to direct immune responses and protect host cells. How the serine protease factor I (FI), assisted by regulators, cleaves either two or three distant peptide bonds in the CUB domain of C3b remains unclear. We present a crystal structure of C3b in complex with FI and regulator factor H (FH; domains 1-4 with 19-20). FI binds C3b-FH between FH domains 2 and 3 and a reoriented C3b C-terminal domain and docks onto the first scissile bond, while stabilizing its catalytic domain for proteolytic activity. One cleavage in C3b does not affect its overall structure, whereas two cleavages unfold CUB and dislodge the thioester-containing domain (TED), affecting binding of regulators and thereby determining the number of cleavages. These data explain how FI generates late-stage opsonins iC3b or C3dg in a context-dependent manner, to react to foreign, danger or healthy self signals.
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Affiliation(s)
- Xiaoguang Xue
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Jin Wu
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Daniel Ricklin
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Federico Forneris
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Patrizia Di Crescenzio
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christoph Q Schmidt
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Joke Granneman
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Thomas H Sharp
- Section Electron Microscopy, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, the Netherlands
| | - John D Lambris
- Department of Pathology &Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Piet Gros
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, the Netherlands
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86
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Lokki AI, Kaartokallio T, Holmberg V, Onkamo P, Koskinen LLE, Saavalainen P, Heinonen S, Kajantie E, Kere J, Kivinen K, Pouta A, Villa PM, Hiltunen L, Laivuori H, Meri S. Analysis of Complement C3 Gene Reveals Susceptibility to Severe Preeclampsia. Front Immunol 2017; 8:589. [PMID: 28611769 PMCID: PMC5446983 DOI: 10.3389/fimmu.2017.00589] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/03/2017] [Indexed: 11/29/2022] Open
Abstract
Preeclampsia (PE) is a common vascular disease of pregnancy with genetic predisposition. Dysregulation of the complement system has been implicated, but molecular mechanisms are incompletely understood. In this study, we determined the potential linkage of severe PE to the most central complement gene, C3. Three cohorts of Finnish patients and controls were recruited for a genetic case-control study. Participants were genotyped using Sequenom genotyping and Sanger sequencing. Initially, we studied 259 Finnish patients with severe PE and 426 controls from the Southern Finland PE and the Finnish population-based PE cohorts. We used a custom-made single nucleotide polymorphism (SNP) genotyping assay consisting of 98 SNPs in 18 genes that encode components of the complement system. Following the primary screening, C3 was selected as the candidate gene and consequently Sanger sequenced. Fourteen SNPs from C3 were also genotyped by a Sequenom panel in 960 patients with severe PE and 705 controls, including already sequenced individuals. Three of the 43 SNPs observed within C3 were associated with severe PE: rs2287845 (p = 0.038, OR = 1.158), rs366510 (p = 0.039, OR = 1.158), and rs2287848 (p = 0.041, OR = 1.155). We also discovered 16 SNP haplotypes with extreme linkage disequilibrium in the middle of the gene with a protective (p = 0.044, OR = 0.628) or a predisposing (p = 0.011, OR = 2.110) effect to severe PE depending on the allele combination. Genetic variants associated with PE are located in key domains of C3 and could thereby influence the function of C3. This is, as far as we are aware, the first candidate gene in the complement system with an association to a clinically relevant PE subphenotype, severe PE. The result highlights a potential role for the complement system in the pathogenesis of PE and may help in defining prognostic and therapeutic subgroups of preeclamptic women.
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Affiliation(s)
- A Inkeri Lokki
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
| | - Tea Kaartokallio
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ville Holmberg
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Clinic of Infectious Diseases, HYKS Inflammation Center, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Päivi Onkamo
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Lotta L E Koskinen
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Päivi Saavalainen
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Seppo Heinonen
- Department of Obstetrics and Gynecology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Eero Kajantie
- Chronic Disease Prevention Unit, Department of Health, National Institute for Health and Welfare, Helsinki, Finland.,Children's Hospital, Helsinki University Hospital, University of Helsinki, Helsinki, Finland.,PEDEGO Research Unit, MRC Oulu, Oulu University Hospital, University of Oulu, Oulu, Finland
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.,Folkhälsan Institute of Genetics, Helsinki, Finland.,Molecular Neurology, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Katja Kivinen
- Division of Cardiovascular Medicine, University of Cambridge, Cambridge, UK
| | - Anneli Pouta
- PEDEGO Research Unit, MRC Oulu, Oulu University Hospital, University of Oulu, Oulu, Finland.,Department of Government Services, National Institute for Health and Welfare, Helsinki, Finland
| | - Pia M Villa
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Department of Obstetrics and Gynecology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | | | - Hannele Laivuori
- Medical and Clinical Genetics, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Department of Obstetrics and Gynecology, Helsinki University Hospital, University of Helsinki, Helsinki, Finland.,Institute for Molecular Medicine Finland, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Immunobiology, Research Programs Unit, University of Helsinki, Helsinki, Finland.,Bacteriology and Immunology, University of Helsinki, Helsinki, Finland
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87
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Garcia BL, Skaff DA, Chatterjee A, Hanning A, Walker JK, Wyckoff GJ, Geisbrecht BV. Identification of C3b-Binding Small-Molecule Complement Inhibitors Using Cheminformatics. THE JOURNAL OF IMMUNOLOGY 2017; 198:3705-3718. [PMID: 28298523 DOI: 10.4049/jimmunol.1601932] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/21/2017] [Indexed: 01/08/2023]
Abstract
The complement system is an elegantly regulated biochemical cascade formed by the collective molecular recognition properties and proteolytic activities of more than two dozen membrane-bound or serum proteins. Complement plays diverse roles in human physiology, such as acting as a sentry against invading microorganisms, priming of the adaptive immune response, and removal of immune complexes. However, dysregulation of complement can serve as a trigger for a wide range of human diseases, which include autoimmune, inflammatory, and degenerative conditions. Despite several potential advantages of modulating complement with small-molecule inhibitors, small-molecule drugs are highly underrepresented in the current complement-directed therapeutics pipeline. In this study, we have employed a cheminformatics drug discovery approach based on the extensive structural and functional knowledge available for the central proteolytic fragment of the cascade, C3b. Using parallel in silico screening methodologies, we identified 45 small molecules that putatively bind C3b near ligand-guided functional hot spots. Surface plasmon resonance experiments resulted in the validation of seven dose-dependent C3b-binding compounds. Competition-based biochemical assays demonstrated the ability of several C3b-binding compounds to interfere with binding of the original C3b ligand that guided their discovery. In vitro assays of complement function identified a single complement inhibitory compound, termed cmp-5, and mechanistic studies of the cmp-5 inhibitory mode revealed it acts at the level of C5 activation. This study has led to the identification of a promising new class of C3b-binding small-molecule complement inhibitors and, to our knowledge, provides the first demonstration of cheminformatics-based, complement-directed drug discovery.
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Affiliation(s)
- Brandon L Garcia
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506
| | - D Andrew Skaff
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110
| | - Arindam Chatterjee
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104; and
| | | | - John K Walker
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104; and
| | - Gerald J Wyckoff
- Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110
| | - Brian V Geisbrecht
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506;
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88
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López-Perrote A, Harrison RES, Subías M, Alcorlo M, Rodríguez de Córdoba S, Morikis D, Llorca O. Ionic tethering contributes to the conformational stability and function of complement C3b. Mol Immunol 2017; 85:137-147. [PMID: 28254726 DOI: 10.1016/j.molimm.2016.12.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 11/28/2022]
Abstract
C3b, the central component of the alternative pathway (AP) of the complement system, coexists as a mixture of conformations in solution. These conformational changes can affect interactions with other proteins and complement regulators. Here we combine a computational model for electrostatic interactions within C3b with molecular imaging to study the conformation of C3b. The computational analysis shows that the TED domain in C3b is tethered ionically to the macroglobulin (MG) ring. Monovalent counterion concentration affects the magnitude of electrostatic forces anchoring the TED domain to the rest of the C3b molecule in a thermodynamic model. This is confirmed by observing NaCl concentration dependent conformational changes using single molecule electron microscopy (EM). We show that the displacement of the TED domain is compatible with C3b binding to Factor B (FB), suggesting that the regulation of the C3bBb convertase could be affected by conditions that promote movement in the TED domain. Our molecular model also predicts mutations that could alter the positioning of the TED domain, including the common R102G polymorphism, a risk variant for developing age-related macular degeneration. The common C3b isoform, C3bS, and the risk isoform, C3bF, show distinct energetic barriers to displacement in the TED that are related to a network of electrostatic interactions at the interface of the TED and MG-ring domains of C3b. These computational predictions agree with experimental evidence that shows differences in conformation observed in C3b isoforms purified from homozygous donors. Altogether, we reveal an ionic, reversible attachment of the TED domain to the MG ring that may influence complement regulation in some mutations and polymorphisms of C3b.
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Affiliation(s)
- Andrés López-Perrote
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain
| | - Reed E S Harrison
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | - Marta Subías
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Martín Alcorlo
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain; Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain.
| | - Dimitrios Morikis
- Department of Bioengineering, University of California, Riverside, CA 92521, USA.
| | - Oscar Llorca
- Centro de Investigaciones Biológicas, Spanish National Research Council (CSIC), Madrid, Spain.
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89
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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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90
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Subías Hidalgo M, Yébenes H, Rodríguez-Gallego C, Martín-Ambrosio A, Domínguez M, Tortajada A, Rodríguez de Córdoba S, Llorca O. Functional and structural characterization of four mouse monoclonal antibodies to complement C3 with potential therapeutic and diagnostic applications. Eur J Immunol 2017; 47:504-515. [PMID: 28083930 DOI: 10.1002/eji.201646758] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/15/2016] [Accepted: 01/11/2017] [Indexed: 01/15/2023]
Abstract
C3 is the central component of the complement system. Upon activation, C3 sequentially generates various proteolytic fragments, C3a, C3b, iC3b, C3dg, each of them exposing novel surfaces, which are sites of interaction with other proteins. C3 and its fragments are therapeutic targets and markers of complement activation. We report the structural and functional characterization of four monoclonal antibodies (mAbs) generated by immunizing C3-deficient mice with a mixture of human C3b, iC3b and C3dg fragments, and discuss their potential applications. This collection includes three mAbs interacting with native C3 and inhibiting AP complement activation; two of them by blocking the cleavage of C3 by the AP C3-converase and one by impeding formation of the AP C3-convertase. The interaction sites of these mAbs in the target molecules were determined by resolving the structures of Fab fragments bound to C3b and/or iC3b using electron microscopy. A fourth mAb specifically recognizes the iC3b, C3dg, and C3d fragments. It binds to an evolutionary-conserved neoepitope generated after C3b cleavage by FI, detecting iC3b/C3dg deposition over opsonized surfaces by flow cytometry and immunohistochemistry in human and other species. Because well-characterized anti-complement mAbs are uncommon, the mAbs reported here may offer interesting therapeutic and diagnostic opportunities.
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Affiliation(s)
- Marta Subías Hidalgo
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Hugo Yébenes
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - César Rodríguez-Gallego
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Adrián Martín-Ambrosio
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Mercedes Domínguez
- Servicio de Inmunología Microbiana, Centro Nacional de Microbiología, Instituto de Investigación Carlos III Madrid, Spain
| | - Agustin Tortajada
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Centro de Investigación Biomédica en Enfermedades Raras, Madrid, Spain
| | - Oscar Llorca
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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91
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Bonyadi M, Jabbarpoor Bonyadi MH, Yaseri M, Mohammadian T, Fotouhi N, Javadzadeh A, Soheilian M. Joint association of complement component 3 and CC-cytokine ligand2 (CCL2) or complement component 3 and CFH polymorphisms in age-related macular degeneration. Ophthalmic Genet 2017; 38:365-370. [DOI: 10.1080/13816810.2016.1242019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Mortaza Bonyadi
- Center of Excellence for Biodiversity, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
- Liver and Gastrointestinal Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Mehdi Yaseri
- Department of Biostatistics and Epidemiology, Tehran University of Medical Sciences, Tehran, Iran
| | - Tahereh Mohammadian
- Center of Excellence for Biodiversity, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
| | - Nikou Fotouhi
- Center of Excellence for Biodiversity, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
| | - Alireza Javadzadeh
- Department of Ophthalmology, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Masoud Soheilian
- Ocular Tissue Engineering Research Center, Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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92
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Yorulmaz S, Jackman JA, Hunziker W, Cho NJ. Influence of membrane surface charge on adsorption of complement proteins onto supported lipid bilayers. Colloids Surf B Biointerfaces 2016; 148:270-277. [DOI: 10.1016/j.colsurfb.2016.08.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/29/2016] [Accepted: 08/21/2016] [Indexed: 10/21/2022]
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93
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Chen Z, Fischer L, Tahir S, Bukowski-Wills JC, Barlow P, Rappsilber J. Quantitative cross-linking/mass spectrometry reveals subtle protein conformational changes. Wellcome Open Res 2016; 1:5. [PMID: 27976756 PMCID: PMC5140025 DOI: 10.12688/wellcomeopenres.9896.1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Quantitative cross-linking/mass spectrometry (QCLMS) probes protein structural dynamics in solution by quantitatively comparing the yields of cross-links between different conformational statuses. We have used QCLMS to understand the final maturation step of the proteasome lid and also to elucidate the structure of complement C3(H2O). Here we benchmark our workflow using a structurally well-described reference system, the human complement protein C3 and its activated cleavage product C3b. We found that small local conformational changes affect the yields of cross-linking residues that are near in space while larger conformational changes affect the detectability of cross-links. Distinguishing between minor and major changes required robust analysis based on replica analysis and a label-swapping procedure. By providing workflow, code of practice and a framework for semi-automated data processing, we lay the foundation for QCLMS as a tool to monitor the domain choreography that drives binary switching in many protein-protein interaction networks.
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Affiliation(s)
- Zhuo Chen
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Lutz Fischer
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Salman Tahir
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Jimi-Carlo Bukowski-Wills
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Paul Barlow
- Schools of Chemistry and Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JJ, UK
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.,Institute of Biotechnology, Technische Universität Berlin, Berlin, 13355, Germany
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94
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Mapping the Complement Factor H-Related Protein 1 (CFHR1):C3b/C3d Interactions. PLoS One 2016; 11:e0166200. [PMID: 27814381 PMCID: PMC5096715 DOI: 10.1371/journal.pone.0166200] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 10/24/2016] [Indexed: 11/19/2022] Open
Abstract
Complement factor H-related protein 1 (CFHR1) is a complement regulator which has been reported to regulate complement by blocking C5 convertase activity and interfering with C5b surface association. CFHR1 also competes with complement factor H (CFH) for binding to C3b, and may act as an antagonist of CFH-directed regulation on cell surfaces. We have employed site-directed mutagenesis in conjunction with ELISA-based and functional assays to isolate the binding interaction that CFHR1 undertakes with complement components C3b and C3d to a single shared interface. The C3b/C3d:CFHR1 interface is identical to that which occurs between the two C-terminal domains (SCR19-20) of CFH and C3b. Moreover, we have been able to corroborate that dimerization of CFHR1 is necessary for this molecule to bind effectively to C3b and C3d, or compete with CFH. Finally, we have established that CFHR1 competes with complement factor H-like protein 1 (CFHL-1) for binding to C3b. CFHL-1 is a CFH gene splice variant, which is almost identical to the N-terminal 7 domains of CFH (SCR1-7). CFHR1, therefore, not only competes with the C-terminus of CFH for binding to C3b, but also sterically blocks the interaction that the N-terminus of CFH undertakes with C3b, and which is required for CFH-regulation.
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95
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Ricklin D, Reis ES, Mastellos DC, Gros P, Lambris JD. Complement component C3 - The "Swiss Army Knife" of innate immunity and host defense. Immunol Rev 2016; 274:33-58. [PMID: 27782325 PMCID: PMC5427221 DOI: 10.1111/imr.12500] [Citation(s) in RCA: 273] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
As a preformed defense system, complement faces a delicate challenge in providing an immediate, forceful response to pathogens even at first encounter, while sparing host cells in the process. For this purpose, it engages a tightly regulated network of plasma proteins, cell surface receptors, and regulators. Complement component C3 plays a particularly versatile role in this process by keeping the cascade alert, acting as a point of convergence of activation pathways, fueling the amplification of the complement response, exerting direct effector functions, and helping to coordinate downstream immune responses. In recent years, it has become evident that nature engages the power of C3 not only to clear pathogens but also for a variety of homeostatic processes ranging from tissue regeneration and synapse pruning to clearing debris and controlling tumor cell progression. At the same time, its central position in immune surveillance makes C3 a target for microbial immune evasion and, if improperly engaged, a trigger point for various clinical conditions. In our review, we look at the versatile roles and evolutionary journey of C3, discuss new insights into the molecular basis for C3 function, provide examples of disease involvement, and summarize the emerging potential of C3 as a therapeutic target.
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Affiliation(s)
- Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Edimara S Reis
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Dimitrios C Mastellos
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
- National Center for Scientific Research 'Demokritos', Athens, Greece
| | - Piet Gros
- Utrecht University, Utrecht, The Netherlands
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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96
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Domain structure of human complement C4b extends with increasing NaCl concentration: implications for its regulatory mechanism. Biochem J 2016; 473:4473-4491. [PMID: 27738201 DOI: 10.1042/bcj20160744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/11/2016] [Accepted: 10/13/2016] [Indexed: 01/06/2023]
Abstract
During the activation of complement C4 to C4b, the exposure of its thioester domain (TED) is crucial for the attachment of C4b to activator surfaces. In the C4b crystal structure, TED forms an Arg104-Glu1032 salt bridge to tether its neighbouring macroglobulin (MG1) domain. Here, we examined the C4b domain structure to test whether this salt bridge affects its conformation. Dual polarisation interferometry of C4b immobilised at a sensor surface showed that the maximum thickness of C4b increased by 0.46 nm with an increase in NaCl concentration from 50 to 175 mM NaCl. Analytical ultracentrifugation showed that the sedimentation coefficient s20,w of monomeric C4b of 8.41 S in 50 mM NaCl buffer decreased to 7.98 S in 137 mM NaCl buffer, indicating that C4b became more extended. Small angle X-ray scattering reported similar RG values of 4.89-4.90 nm for C4b in 137-250 mM NaCl. Atomistic scattering modelling of the C4b conformation showed that TED and the MG1 domain were separated by 4.7 nm in 137-250 mM NaCl and this is greater than that of 4.0 nm in the C4b crystal structure. Our data reveal that in low NaCl concentrations, both at surfaces and in solution, C4b forms compact TED-MG1 structures. In solution, physiologically relevant NaCl concentrations lead to the separation of the TED and MG1 domain, making C4b less capable of binding to its complement regulators. These conformational changes are similar to those seen previously for complement C3b, confirming the importance of this salt bridge for regulating both C4b and C3b.
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97
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Creating functional sophistication from simple protein building blocks, exemplified by factor H and the regulators of complement activation. Biochem Soc Trans 2016; 43:812-8. [PMID: 26517887 DOI: 10.1042/bst20150074] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Complement control protein modules (CCPs) occur in numerous functionally diverse extracellular proteins. Also known as short consensus repeats (SCRs) or sushi domains each CCP contains approximately 60 amino acid residues, including four consensus cysteines participating in two disulfide bonds. Varying in length and sequence, CCPs adopt a β-sandwich type fold and have an overall prolate spheroidal shape with N- and C-termini lying close to opposite poles of the long axis. CCP-containing proteins are important as cytokine receptors and in neurotransmission, cell adhesion, blood clotting, extracellular matrix formation, haemoglobin metabolism and development, but CCPs are particularly well represented in the vertebrate complement system. For example, factor H (FH), a key soluble regulator of the alternative pathway of complement activation, is made up entirely from a chain of 20 CCPs joined by short linkers. Collectively, therefore, the 20 CCPs of FH must mediate all its functional capabilities. This is achieved via collaboration and division of labour among these modules. Structural studies have illuminated the dynamic architectures that allow FH and other CCP-rich proteins to perform their biological functions. These are largely the products of a highly varied set of intramolecular interactions between CCPs. The CCP can act as building block, spacer, highly versatile recognition site or dimerization mediator. Tandem CCPs may form composite binding sites or contribute to flexible, rigid or conformationally 'switchable' segments of the parent proteins.
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98
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Meri S. Self-nonself discrimination by the complement system. FEBS Lett 2016; 590:2418-34. [PMID: 27393384 DOI: 10.1002/1873-3468.12284] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 06/29/2016] [Accepted: 07/06/2016] [Indexed: 01/09/2023]
Abstract
The alternative pathway (AP) of complement can recognize nonself structures by only two molecules, C3b and factor H. The AP deposits C3b covalently on nonself structures via an amplification system. The actual discrimination is performed by factor H, which has binding sites for polyanions (sialic acids, glycosaminoglycans, phospholipids). This robust recognition of 'self' protects our own intact viable cells and tissues, while activating structures are recognized by default. Foreign targets are opsonized for phagocytosis or killed. Mutations in factor H predispose to severe diseases. In hemolytic uremic syndrome, they promote complement attack against blood cells and vascular endothelial cells and lead, for example, to kidney and brain damage. Even pathogens can exploit factor H. In fact, the ability to bind factor H discriminates most pathogenic microbes from nonpathogenic ones.
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Affiliation(s)
- Seppo Meri
- Immunobiology, Research Programs Unit, Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Finland.,HUSLAB, Helsinki University Hospital, Finland.,Humanitas University, Milan, Italy
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99
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Ricklin D, Lambris JD. Therapeutic control of complement activation at the level of the central component C3. Immunobiology 2016; 221:740-6. [PMID: 26101137 PMCID: PMC4675703 DOI: 10.1016/j.imbio.2015.06.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/02/2015] [Accepted: 06/05/2015] [Indexed: 02/06/2023]
Abstract
The increasing recognition of the complement system's association with diseases of the inflammatory spectrum and with biomaterial and transplant-related complications has generated growing interest in the therapeutic modulation of this innate immune cascade. As a central functional hub that largely drives the activation, amplification, and effector generation of the complement response, the plasma protein C3 has long been recognized as an attractive target. While pharmacological modulation of C3 activation may offer a powerful opportunity to interfere with or even prevent complement-driven pathologies, the development of C3 inhibitors has often been accompanied by concerns regarding the safety and feasibility of this approach. Although no C3-targeted inhibitors have thus far been approved for clinical use, several promising concepts and candidates have emerged in recent years. At the same time, experiences from preclinical development and clinical trials are slowly providing a more detailed picture of therapeutic complement inhibition at the level of C3. This review highlights the current therapeutic strategies to control C3 activation and discusses the possibilities and challenges on the road to bringing C3-targeted therapeutics to the clinic.
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Affiliation(s)
- Daniel Ricklin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, USA.
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, USA
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100
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Chen ZA, Pellarin R, Fischer L, Sali A, Nilges M, Barlow PN, Rappsilber J. Structure of Complement C3(H2O) Revealed By Quantitative Cross-Linking/Mass Spectrometry And Modeling. Mol Cell Proteomics 2016; 15:2730-43. [PMID: 27250206 PMCID: PMC4974347 DOI: 10.1074/mcp.m115.056473] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Indexed: 11/30/2022] Open
Abstract
The slow but spontaneous and ubiquitous formation of C3(H2O), the hydrolytic and conformationally rearranged product of C3, initiates antibody-independent activation of the complement system that is a key first line of antimicrobial defense. The structure of C3(H2O) has not been determined. Here we subjected C3(H2O) to quantitative cross-linking/mass spectrometry (QCLMS). This revealed details of the structural differences and similarities between C3(H2O) and C3, as well as between C3(H2O) and its pivotal proteolytic cleavage product, C3b, which shares functionally similarity with C3(H2O). Considered in combination with the crystal structures of C3 and C3b, the QCMLS data suggest that C3(H2O) generation is accompanied by the migration of the thioester-containing domain of C3 from one end of the molecule to the other. This creates a stable C3b-like platform able to bind the zymogen, factor B, or the regulator, factor H. Integration of available crystallographic and QCLMS data allowed the determination of a 3D model of the C3(H2O) domain architecture. The unique arrangement of domains thus observed in C3(H2O), which retains the anaphylatoxin domain (that is excised when C3 is enzymatically activated to C3b), can be used to rationalize observed differences between C3(H2O) and C3b in terms of complement activation and regulation.
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Affiliation(s)
- Zhuo A Chen
- From the ‡Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Riccardo Pellarin
- §Unité de Bioinformatique Structurale, CNRS UMR 3528, Institut Pasteur, 75015 Paris, France; ¶Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Sciences, and California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, California 94158, United States
| | - Lutz Fischer
- From the ‡Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Andrej Sali
- ¶Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Sciences, and California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, California 94158, United States
| | - Michael Nilges
- §Unité de Bioinformatique Structurale, CNRS UMR 3528, Institut Pasteur, 75015 Paris, France
| | - Paul N Barlow
- ‖Schools of Chemistry and Biological Sciences, University of Edinburgh, Edinburgh EH9 3JJ, UK;
| | - Juri Rappsilber
- From the ‡Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK; **Chair of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355 Berlin, Germany
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